Multitarget transcranial direct current stimulation for freezing of gait in Parkinson's disease.

Science.gov (United States)

Dagan, Moria; Herman, Talia; Harrison, Rachel; Zhou, Junhong; Giladi, Nir; Ruffini, Giulio; Manor, Brad; Hausdorff, Jeffrey M

2018-04-01

Recent findings suggest that transcranial direct current stimulation of the primary motor cortex may ameliorate freezing of gait. However, the effects of multitarget simultaneous stimulation of motor and cognitive networks are mostly unknown. The objective of this study was to evaluate the effects of multitarget transcranial direct current stimulation of the primary motor cortex and left dorsolateral prefrontal cortex on freezing of gait and related outcomes. Twenty patients with Parkinson's disease and freezing of gait received 20 minutes of transcranial direct current stimulation on 3 separate visits. Transcranial direct current stimulation targeted the primary motor cortex and left dorsolateral prefrontal cortex simultaneously, primary motor cortex only, or sham stimulation (order randomized and double-blinded assessments). Participants completed a freezing of gait-provoking test, the Timed Up and Go, and the Stroop test before and after each transcranial direct current stimulation session. Performance on the freezing of gait-provoking test (P = 0.010), Timed Up and Go (P = 0.006), and the Stroop test (P = 0.016) improved after simultaneous stimulation of the primary motor cortex and left dorsolateral prefrontal cortex, but not after primary motor cortex only or sham stimulation. Transcranial direct current stimulation designed to simultaneously target motor and cognitive regions apparently induces immediate aftereffects in the brain that translate into reduced freezing of gait and improvements in executive function and mobility. © 2018 International Parkinson and Movement Disorder Society. © 2018 International Parkinson and Movement Disorder Society.

Effect of high-frequency repetitive transcranial magnetic stimulation on chronic central pain after mild traumatic brain injury: A pilot study.

Science.gov (United States)

Choi, Gyu-Sik; Kwak, Sang Gyu; Lee, Han Do; Chang, Min Cheol

2018-02-28

Central pain can occur following traumatic brain injury, leading to poor functional recovery, limitation of activities of daily living, and decreased quality of life. The aim of this study was to determine whether high-frequency (10 Hz) repetitive transcranial magnetic stimulation, applied over the primary motor cortex of the affected hemisphere, can be used to manage chronic central pain after mild traumatic brain injury. Prospective randomized feasibility study. Twelve patients with mild traumatic brain injury and chronic central pain were randomly assigned to transcranial magnetic stimulation (high-frequency stimulation, 10 sessions) or sham groups. Diffuse tensor tractography revealed partially injured spinothalamocortical tracts in all recruited patients. A numerical rating scale (NRS) was used to evaluate pain intensity during pre-treatment and immediately after the 5th transcranial magnetic stimulation session (post1), 10th transcranial magnetic stimulation session (post2), and 1 (post3), 2 (post4), and 4 weeks (post 5) after finishing treatment. Physical and mental health status were evaluated using the Short Form 36 Health Survey (SF-36), including physical and mental component scores (PCS, MCS). The NRS score of the repetitive transcranial magnetic stimulation group was significantly lower than the sham group score at all clinical evaluation time-points during and after transcranial magnetic stimulation sessions. The transcranial magnetic stimulation group's SF-36 PCS score was significantly higher at post2, post3, post4, and post5 compared with the sham group. High-frequency transcranial magnetic stimulation may be used to manage chronic central pain and improve quality of life in patients with mild traumatic brain injury. However, this is a pilot study and further research is needed.

Is sham cTBS real cTBS? The effect on EEG dynamics

Directory of Open Access Journals (Sweden)

Alexander eOpitz

2015-01-01

Full Text Available Increasing sensitivity of modern evaluation tools allows for the study of weaker electric stimulation effects on neural populations. In the current study we examined the effects of sham continuous theta burst (cTBS transcranial magnetic stimulation to the left dorsolateral prefrontal cortex (DLPFC upon somatosensory evoked potentials (SEP and frontal-parietal phase coupling of alpha and beta bands. Sham TMS results in an induced electric field amplitude roughly 5% that of real TMS with a similar spatial extent in cortex. Both real and sham cTBS reduced the amplitude of the frontal P14-N30 SEP and increased local phase coupling in the alpha-beta frequency bands of left frontal cortex. In addition, both sham and real cTBS increased frontal-parietal phase coupling in the alpha-beta bands concomitant with an increase in amplitude of parietal P50-N70 complex. These data suggest that weak electric fields from sham cTBS can affect both local and downstream neuronal circuits, though in a different manner than high strength TMS.

Is sham cTBS real cTBS? The effect on EEG dynamics.

Science.gov (United States)

Opitz, Alexander; Legon, Wynn; Mueller, Jerel; Barbour, Aaron; Paulus, Walter; Tyler, William J

2014-01-01

Increasing sensitivity of modern evaluation tools allows for the study of weaker electric stimulation effects on neural populations. In the current study we examined the effects of sham continuous theta burst (cTBS) transcranial magnetic stimulation to the left dorsolateral prefrontal cortex (DLPFC) upon somatosensory evoked potentials (SEP) and frontal-parietal phase coupling of alpha and beta bands. Sham TMS results in an induced electric field amplitude roughly 5% that of real TMS with a similar spatial extent in cortex. Both real and sham cTBS reduced the amplitude of the frontal P14-N30 SEP and increased local phase coupling in the alpha-beta frequency bands of left frontal cortex. In addition, both sham and real cTBS increased frontal-parietal phase coupling in the alpha-beta bands concomitant with an increase in amplitude of parietal P50-N70 complex. These data suggest that weak electric fields from sham cTBS can affect both local and downstream neuronal circuits, though in a different manner than high strength TMS.

Comparing the Efficacy of Excitatory Transcranial Stimulation Methods Measuring Motor Evoked Potentials

Directory of Open Access Journals (Sweden)

Vera Moliadze

2014-01-01

Full Text Available The common aim of transcranial stimulation methods is the induction or alterations of cortical excitability in a controlled way. Significant effects of each individual stimulation method have been published; however, conclusive direct comparisons of many of these methods are rare. The aim of the present study was to compare the efficacy of three widely applied stimulation methods inducing excitability enhancement in the motor cortex: 1 mA anodal transcranial direct current stimulation (atDCS, intermittent theta burst stimulation (iTBS, and 1 mA transcranial random noise stimulation (tRNS within one subject group. The effect of each stimulation condition was quantified by evaluating motor-evoked-potential amplitudes (MEPs in a fixed time sequence after stimulation. The analyses confirmed a significant enhancement of the M1 excitability caused by all three types of active stimulations compared to sham stimulation. There was no significant difference between the types of active stimulations, although the time course of the excitatory effects slightly differed. Among the stimulation methods, tRNS resulted in the strongest and atDCS significantly longest MEP increase compared to sham. Different time courses of the applied stimulation methods suggest different underlying mechanisms of action. Better understanding may be useful for better targeting of different transcranial stimulation techniques.

Online effects of transcranial direct current stimulation on prefrontal metabolites in gambling disorder.

Science.gov (United States)

Dickler, Maya; Lenglos, Christophe; Renauld, Emmanuelle; Ferland, Francine; Edden, Richard A; Leblond, Jean; Fecteau, Shirley

2018-03-15

Gambling disorder is characterized by persistent maladaptive gambling behaviors and is now considered among substance-related and addictive disorders. There is still unmet therapeutic need for these clinical populations, however recent advances indicate that interventions targeting the Glutamatergic/GABAergic system hold promise in reducing symptoms in substance-related and addictive disorders, including gambling disorder. There is some data indicating that transcranial direct current stimulation may hold clinical benefits in substance use disorders and modulate levels of brain metabolites including glutamate and GABA. The goal of the present work was to test whether this non-invasive neurostimulation method modulates key metabolites in gambling disorder. We conducted a sham-controlled, crossover, randomized study, blinded at two levels in order to characterize the effects of transcranial direct current stimulation over the dorsolateral prefrontal cortex on neural metabolites levels in sixteen patients with gambling disorder. Metabolite levels were measured with magnetic resonance spectroscopy from the right dorsolateral prefrontal cortex and the right striatum during active and sham stimulation. Active as compared to sham stimulation elevated prefrontal GABA levels. There were no significant changes between stimulation conditions in prefrontal glutamate + glutamine and N-acetyl Aspartate, or in striatal metabolite levels. Results also indicated positive correlations between metabolite levels during active, but not sham, stimulation and levels of risk taking, impulsivity and craving. Our findings suggest that transcranial direct current stimulation can modulate GABA levels in patients with gambling disorder which may represent an interesting future therapeutic avenue. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of high-frequency repetitive transcranial magnetic stimulation on chronic central pain after mild traumatic brain injury: A pilot study

Directory of Open Access Journals (Sweden)

Gyu-sik Choi

2018-01-01

Full Text Available Objective: Central pain can occur following traumatic brain injury, leading to poor functional recovery, limitation of activities of daily living, and decreased quality of life. The aim of this study was to determine whether high-frequency (10 Hz repetitive transcranial magnetic stimulation, applied over the primary motor cortex of the affected hemisphere, can be used to manage chronic central pain after mild traumatic brain injury. Design: Prospective randomized feasibility study. Methods: Twelve patients with mild traumatic brain injury and chronic central pain were randomly assigned to transcranial magnetic stimulation (high-frequency stimulation, 10 sessions or sham groups. Diffuse tensor tractography revealed partially injured spinothalamocortical tracts in all recruited patients. A numerical rating scale (NRS was used to evaluate pain intensity during pre-treatment and immediately after the 5th transcranial magnetic stimulation session (post1, 10th transcranial magnetic stimulation session (post2, and 1 (post3, 2 (post4, and 4 weeks (post 5 after finishing treatment. Physical and mental health status were evaluated using the Short Form 36 Health Survey (SF-36, including physical and mental component scores (PCS, MCS. Results: The NRS score of the repetitive transcranial magnetic stimulation group was significantly lower than the sham group score at all clinical evaluation time-points during and after transcranial magnetic stimulation sessions. The transcranial magnetic stimulation group’s SF-36 PCS score was significantly higher at post2, post3, post4, and post5 compared with the sham group. Conclusion: High-frequency transcranial magnetic stimulation may be used to manage chronic central pain and improve quality of life in patients with mild traumatic brain injury. However, this is a pilot study and further research is needed.

Transcranial low voltage pulsed electromagnetic fields in patients with treatment-resistant depression

DEFF Research Database (Denmark)

Martiny, Klaus Per Juul; Lunde, Marianne; Bech, Per

2010-01-01

BACKGROUND: Approximately 30% of patients with depression are resistant to antidepressant drugs. Repetitive transcranial magnetic stimulation (rTMS) has been found effective in combination with antidepressants in this patient group. The aim of this study was to evaluate the antidepressant effect...... of a new principle using low-intensity transcranially applied pulsed electromagnetic fields (T-PEMF) in combination with antidepressants in patients with treatment-resistant depression. METHODS: This was a sham-controlled double-blind study comparing 5 weeks of active or sham T-PEMF in patients...... with treatment-resistant major depression. The antidepressant treatment, to which patients had been resistant, was unchanged 4 weeks before and during the study period. Weekly assessments were performed using both clinician-rated and patient-rated scales. The T-PEMF equipment was designed as a helmet containing...

Randomized, sham-controlled trial based on transcranial direct current stimulation and wrist robot-assisted integrated treatment on subacute stroke patients: Intermediate results.

Science.gov (United States)

Mazzoleni, Stefano; Tran, Vi Do; Iardella, Laura; Dario, Paolo; Posteraro, Federico

2017-07-01

The main goal of this study is to analyse the effects of combined transcranial direct current stimulation (tDCS) and wrist robot-assisted therapy in subacute stroke patients. Twenty-four patients were included in this study and randomly assigned to the experimental (EG) or control group (CG). All participants performed wrist robot-assisted training a) in conjunction with tDCS (real stimulation for patients in EG) or b) without tDCS (sham stimulation for patients in CG). Clinical scales and kinematic parameters recorded by the robot were used for the assessment. Clinical outcome measures show a significant decrease in motor impairment after the treatment in both groups. Kinematic data show several significant improvements after the integrated therapy in both groups. However, no significant differences in both clinical outcome measures and kinematic parameters was found between two groups. The potential advantages of combined tDCS and wrist robot-assisted therapy in subacute stroke patients are still unclear.

Effects of Navigated Repetitive Transcranial Magnetic Stimulation After Stroke.

Science.gov (United States)

Chervyakov, Alexander V; Poydasheva, Alexandra G; Lyukmanov, Roman H; Suponeva, Natalia A; Chernikova, Ludmila A; Piradov, Michael A; Ustinova, Ksenia I

2018-03-01

The purpose of this study was to test the effects of navigated repetitive transcranial magnetic stimulation, delivered in different modes, on motor impairments and functional limitations after stroke. The study sample included 42 patients (58.5 ± 10.7 years; 26 males) who experienced a single unilateral stroke (1-12 months previously) in the area of the middle cerebral artery. Patients completed a course of conventional rehabilitation, together with 10 sessions of navigated repetitive transcranial magnetic stimulation or sham stimulation. Stimulation was scheduled five times a week over two consecutive weeks in an inpatient clinical setting. Patients were randomly assigned to one of four groups and received sham stimulation (n = 10), low-frequency (1-Hz) stimulation of the nonaffected hemisphere (n = 11), high-frequency (10-Hz) stimulation of the affected hemisphere (n = 13), or sequential combination of low- and high-frequency stimulations (n = 8). Participants were evaluated before and after stimulation with clinical tests, including the arm and hand section of the Fugl-Meyer Assessment Scale, modified Ashworth Scale of Muscle Spasticity, and Barthel Index of Activities of Daily Living. Participants in the three groups receiving navigated repetitive transcranial magnetic stimulation showed improvements in arm and hand functions on the Fugl-Meyer Stroke Assessment Scale. Ashworth Scale of Muscle Spasticity and Barthel Index scores were significantly reduced in groups receiving low- or high-frequency stimulation alone. Including navigated repetitive transcranial magnetic stimulation in a conventional rehabilitation program positively influenced motor and functional recovery in study participants, demonstrating the clinical potential of the method. The results of this study will be used for designing a large-scale clinical trial.

The Emperors sham - wrong assumption that sham needling is sham.

Science.gov (United States)

Lundeberg, Thomas; Lund, Iréne; Näslund, Jan; Thomas, Moolamanil

2008-12-01

During the last five years a large number of randomised controlled clinical trials (RCTs) have been published on the efficacy of acupuncture in different conditions. In most of these studies verum is compared with sham acupuncture. In general both verum and sham have been found to be effective, and often with little reported difference in outcome. This has repeatedly led to the conclusion that acupuncture is no more effective than placebo treatment. However, this conclusion is based on the assumption that sham acupuncture is inert. Since sham acupuncture evidently is merely another form of acupuncture from the physiological perspective, the assumption that sham is sham is incorrect and conclusions based on this assumption are therefore invalid. Clinical guidelines based on such conclusions may therefore exclude suffering patients from valuable treatments.

Effect of high-frequency repetitive transcranial magnetic stimulation on motor cortical excitability and sensory nerve conduction velocity in subacute-stage incomplete spinal cord injury patients.

Science.gov (United States)

Cha, Hyun Gyu; Ji, Sang-Goo; Kim, Myoung-Kwon

2016-07-01

[Purpose] The aim of the present study was to determine whether repetitive transcranial magnetic stimulation can improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients. [Subjects and Methods] This study was conducted on 20 subjects with diagnosed paraplegia due to spinal cord injury. These 20 subjects were allocated to an experimental group of 10 subjects that underwent active repetitive transcranial magnetic stimulation or to a control group of 10 subjects that underwent sham repetitive transcranial magnetic stimulation. The SCI patients in the experimental group underwent active repetitive transcranial magnetic stimulation and conventional rehabilitation therapy, whereas the spinal cord injury patients in the control group underwent sham repetitive transcranial magnetic stimulation and conventional rehabilitation therapy. Participants in both groups received therapy five days per week for six-weeks. Latency, amplitude, and sensory nerve conduction velocity were assessed before and after the six week therapy period. [Results] A significant intergroup difference was observed for posttreatment velocity gains, but no significant intergroup difference was observed for amplitude or latency. [Conclusion] repetitive transcranial magnetic stimulation may be improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients.

Effect of transcranial direct current stimulation on neuroplasticity in corticomotor pathways of the tongue muscles

DEFF Research Database (Denmark)

Kothari, Mohit; Stubbs, Peter William; Figlewski, Krystian

2017-01-01

To investigate effects of transcranial direct current stimulation (tDCS) on neuroplasticity in corticomotor pathways related to tongue muscles evoked by a training task using the Tongue Drive System (TDS). Using a cross-over design, 13 healthy participants completed two sessions of tDCS while...... performing 30 min of TDS training. Sessions were spaced at least 2 weeks apart and participants randomly received anodal and sham tDCS stimulation in the first session and the other condition in the second session. Single and paired pulse transcranial magnetic stimulation was used to elicit motor evoked...... potentials (MEPs) of the tongue at three time-points; before, immediately after and 30 min after training. Participant-based reports of fun, pain, fatigue and motivation, level of difficulty and effort were evaluated on numerical rating scales. There was no consistent significant effect of anodal and sham...

Multiday Transcranial Direct Current Stimulation Causes Clinically Insignificant Changes in Childhood Dystonia: A Pilot Study.

Science.gov (United States)

Bhanpuri, Nasir H; Bertucco, Matteo; Young, Scott J; Lee, Annie A; Sanger, Terence D

2015-10-01

Abnormal motor cortex activity is common in dystonia. Cathodal transcranial direct current stimulation may alter cortical activity by decreasing excitability while anodal stimulation may increase motor learning. Previous results showed that a single session of cathodal transcranial direct current stimulation can improve symptoms in childhood dystonia. Here we performed a 5-day, sham-controlled, double-blind, crossover study, where we measured tracking and muscle overflow in a myocontrol-based task. We applied cathodal and anodal transcranial direct current stimulation (2 mA, 9 minutes per day). For cathodal transcranial direct current stimulation (7 participants), 3 subjects showed improvements whereas 2 showed worsening in overflow or tracking error. The effect size was small (about 1% of maximum voluntary contraction) and not clinically meaningful. For anodal transcranial direct current stimulation (6 participants), none showed improvement, whereas 5 showed worsening. Thus, multiday cathodal transcranial direct current stimulation reduced symptoms in some children but not to a clinically meaningful extent, whereas anodal transcranial direct current stimulation worsened symptoms. Our results do not support transcranial direct current stimulation as clinically viable for treating childhood dystonia. © The Author(s) 2015.

Mitigating cutaneous sensation differences during tDCS: comparing sham versus low intensity control conditions.

Science.gov (United States)

Brunyé, Tad T; Cantelon, Julie; Holmes, Amanda; Taylor, Holly A; Mahoney, Caroline R

2014-01-01

Cutaneous sensations at electrode sites during the administration of direct current brain stimulation may inadvertently influence participants' subjective experience and task performance. The present study evaluated the utility of a methodological variation that substitutes sham administration with very low intensity (0.5 mA) current delivery. We used a 4 × 1 high-definition ring electrode transcranial direct current (HD-tDCS) system to target the left dorsolateral prefrontal cortex (Brodmann's Area 9). Four stimulation conditions were compared in a repeated-measures design: sham 2.0 mA and 0.5 mA intensity, versus active 2.0 mA and 0.5 mA intensity. During stimulation participants performed a cognitive interference task that activates the cingulo-frontal-parietal network, and periodically provided perceived sensation ratings. We demonstrate that a relatively low intensity control condition attenuates otherwise large differences in perceived sensation between active and sham conditions. Critically, behavioral task differences maintained between the two active conditions. A low intensity control stimulation condition may prove a viable methodological alternative to conventional sham techniques used in repeated-measures designs, though important limitations are discussed. Published by Elsevier Inc.

Effect of Cathodal Transcranial Direct Current Stimulation on a Child with Involuntary Movement after Hypoxic Encephalopathy

Directory of Open Access Journals (Sweden)

Mayumi Nagai

2018-01-01

Full Text Available The aim of the study was to investigate the effect of cathodal transcranial direct current stimulation to the supplementary motor area to inhibit involuntary movements of a child. An 8-year-old boy who developed hypoxic encephalopathy after asphyxia at the age of 2 had difficulty in remaining standing without support because of involuntary movements. He was instructed to remain standing with his plastic ankle-foot orthosis for 10 s at three time points by leaning forward with his forearms on a desk. He received cathodal or sham transcranial direct current stimulation to the supplementary motor area at 1 mA for 10 min. Involuntary movements during standing were measured using an accelerometer attached to his forehead. The low-frequency power of involuntary movements during cathodal transcranial direct current stimulation significantly decreased compared with that during sham stimulation. No adverse effects were observed. Involuntary movement reduction by cathodal stimulation to supplementary motor areas suggests that stimulations modulated the corticobasal ganglia motor circuit. Cathodal stimulation to supplementary motor areas may be effective for reducing involuntary movements and may be safely applied to children with movement disorders.

Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation on Naming Abilities in Early-Stroke Aphasic Patients: A Prospective, Randomized, Double-Blind Sham-Controlled Study

Directory of Open Access Journals (Sweden)

Konrad Waldowski

2012-01-01

Full Text Available Background and Purpose. Functional brain imaging studies with aphasia patients have shown increased cortical activation in the right hemisphere language homologues, which hypothetically may represent a maladaptive strategy that interferes with aphasia recovery. The aim of this study was to investigate whether low-frequency repetitive transcranial magnetic stimulation (rTMS over the Broca’s homologues in combination with speech/language therapy improves naming in early-stroke aphasia patients. Methods. 26 right-handed aphasic patients in the early stage (up to 12 weeks of a first-ever left hemisphere ischemic stroke were randomized to receive speech and language therapy combined with real or sham rTMS. Prior to each 45-minute therapeutic session (15 sessions, 5 days a week, 30 minutes of 1-Hz rTMS was applied. Outcome measures were obtained at baseline, immediately after 3 weeks of experimental treatment and 15 weeks; posttreatment using the Computerized Picture Naming Test. Results. Although both groups significantly improved their naming abilities after treatment, no significant differences were noted between the rTMS and sham stimulation groups. The additional analyses have revealed that the rTMS subgroup with a lesion including the anterior part of language area showed greater improvement primarily in naming reaction time 15 weeks after completion of the therapeutic treatment. Improvement was also demonstrated in functional communication abilities. Conclusions. Inhibitory rTMS of the unaffected right inferior frontal gyrus area in combination with speech and language therapy cannot be assumed as an effective method for all poststroke aphasia patients. The treatment seems to be beneficial for patients with frontal language area damage, mostly in the distant time after finishing rTMS procedure.

Enhanced accuracy in novel mirror drawing after repetitive transcranial magnetic stimulation-induced proprioceptive deafferentation

DEFF Research Database (Denmark)

Balslev, Daniela; Christensen, Lars O.D.; Lee, Ji-hang

2004-01-01

a performance benefit. In this study, we tested whether deafferentation induced by repetitive transcranial magnetic stimulation (rTMS) can improve mirror tracing skills in normal subjects. Hand trajectory error during novel mirror drawing was compared across two groups of subjects that received either 1 Hz r......TMS over the somatosensory cortex contralateral to the hand or sham stimulation. Mirror tracing was more accurate after rTMS than after sham stimulation. Using a position-matching task, we confirmed that rTMS reduced proprioceptive acuity and that this reduction was largest when the coil was placed...

Non-invasive brain stimulation and computational models in post-stroke aphasic patients: single session of transcranial magnetic stimulation and transcranial direct current stimulation. A randomized clinical trial

Directory of Open Access Journals (Sweden)

Michele Devido dos Santos

2017-11-01

Full Text Available ABSTRACT CONTEXT AND OBJECTIVE: Patients undergoing the same neuromodulation protocol may present different responses. Computational models may help in understanding such differences. The aims of this study were, firstly, to compare the performance of aphasic patients in naming tasks before and after one session of transcranial direct current stimulation (tDCS, transcranial magnetic stimulation (TMS and sham, and analyze the results between these neuromodulation techniques; and secondly, through computational model on the cortex and surrounding tissues, to assess current flow distribution and responses among patients who received tDCS and presented different levels of results from naming tasks. DESIGN AND SETTING: Prospective, descriptive, qualitative and quantitative, double blind, randomized and placebo-controlled study conducted at Faculdade de Ciências Médicas da Santa Casa de São Paulo. METHODS: Patients with aphasia received one session of tDCS, TMS or sham stimulation. The time taken to name pictures and the response time were evaluated before and after neuromodulation. Selected patients from the first intervention underwent a computational model stimulation procedure that simulated tDCS. RESULTS: The results did not indicate any statistically significant differences from before to after the stimulation.The computational models showed different current flow distributions. CONCLUSIONS: The present study did not show any statistically significant difference between tDCS, TMS and sham stimulation regarding naming tasks. The patients’responses to the computational model showed different patterns of current distribution.

Slow oscillating transcranial direct current stimulation during sleep has a sleep-stabilizing effect in chronic insomnia: a pilot study.

Science.gov (United States)

Saebipour, Mohammad R; Joghataei, Mohammad T; Yoonessi, Ali; Sadeghniiat-Haghighi, Khosro; Khalighinejad, Nima; Khademi, Soroush

2015-10-01

Recent evidence suggests that lack of slow-wave activity may play a fundamental role in the pathogenesis of insomnia. Pharmacological approaches and brain stimulation techniques have recently offered solutions for increasing slow-wave activity during sleep. We used slow (0.75 Hz) oscillatory transcranial direct current stimulation during stage 2 of non-rapid eye movement sleeping insomnia patients for resonating their brain waves to the frequency of sleep slow-wave. Six patients diagnosed with either sleep maintenance or non-restorative sleep insomnia entered the study. After 1 night of adaptation and 1 night of baseline polysomnography, patients randomly received sham or real stimulation on the third and fourth night of the experiment. Our preliminary results show that after termination of stimulations (sham or real), slow oscillatory transcranial direct current stimulation increased the duration of stage 3 of non-rapid eye movement sleep by 33 ± 26 min (P = 0.026), and decreased stage 1 of non-rapid eye movement sleep duration by 22 ± 17.7 min (P = 0.028), compared with sham. Slow oscillatory transcranial direct current stimulation decreased stage 1 of non-rapid eye movement sleep and wake time after sleep-onset durations, together, by 55.4 ± 51 min (P = 0.045). Slow oscillatory transcranial direct current stimulation also increased sleep efficiency by 9 ± 7% (P = 0.026), and probability of transition from stage 2 to stage 3 of non-rapid eye movement sleep by 20 ± 17.8% (P = 0.04). Meanwhile, slow oscillatory transcranial direct current stimulation decreased transitions from stage 2 of non-rapid eye movement sleep to wake by 12 ± 6.7% (P = 0.007). Our preliminary results suggest a sleep-stabilizing role for the intervention, which may mimic the effect of sleep slow-wave-enhancing drugs. © 2015 European Sleep Research Society.

Valuation of switchable tariff for wind energy

International Nuclear Information System (INIS)

Yu, Wang; Sheble, Gerald B.; Lopes, Joao A. Pecas; Matos, Manuel Antonio

2006-01-01

The current fixed tariff remuneration for wind energy is not compatible with the deregulation of the electric power industry. The time-varying and location-dependent value of renewable energy is not acknowledged. The newly announced switchable tariff for wind energy in the Spanish electricity market provides a promising solution to compensating renewable energy within the deregulated electric power industry. The new switchable tariff provides wind generators more flexibility in operating wind generation assets. Such flexibilities provide option value in coordinating the seasonality of wind energy, demand on electric power and electricity prices movement. This paper models and valuates the flexibility on switching tariff as real compound options for wind generators. Numerical examples valuate wind generation assets under fixed tariff, spot market price taking, and yearly and monthly switchable tariffs. The optimal switching strategies are identified. The impacts of the switchable tariff on sitting criteria and values of wind generation assets are investigated. An improvement on the yearly switchable tariff is suggested to further reduce the operation risk of wind generators and fully explore the efficiency provided by competitive electricity markets. (author)

Transcranial Direct Current Stimulation Does Not Improve Language Outcome in Subacute Poststroke Aphasia.

Science.gov (United States)

Spielmann, Kerstin; van de Sandt-Koenderman, W Mieke E; Heijenbrok-Kal, Majanka H; Ribbers, Gerard M

2018-04-01

The aim of the present study is to investigate the effect of transcranial direct current stimulation on word-finding treatment outcome in subacute poststroke aphasia. In this multi-center, double-blind, randomized controlled trial with 6-month follow-up, we included 58 patients with subacute aphasia (transcranial direct current stimulation (1 mA, 20 minutes; experimental group) or sham transcranial direct current stimulation (control group) over the left inferior frontal gyrus. The primary outcome measure was the Boston Naming Test. Secondary outcome measures included naming performance for trained/untrained picture items and verbal communication. Both the experimental (n=26) and the control group (n=32) improved on the Boston Naming Test over the intervention period and 6-month follow-up; however, there were no significant differences between groups. Also for the secondary outcome measures, no significant differences were found. The results of the present study do not support an effect of transcranial direct current stimulation as an adjuvant treatment in subacute poststroke aphasia. URL: http://www.trialregister.nl/trialreg/admin/rctview.asp. Unique identifier: NTR4364. © 2018 American Heart Association, Inc.

Effects of Transcranial Direct Current Stimulation (tDCS) on Behaviour and Electrophysiology of Language Production

Science.gov (United States)

Wirth, Miranka; Rahman, Rasha Abdel; Kuenecke, Janina; Koenig, Thomas; Horn, Helge; Sommer, Werner; Dierks, Thomas

2011-01-01

Excitatory anodal transcranial direct current stimulation (A-tDCS) over the left dorsal prefrontal cortex (DPFC) has been shown to improve language production. The present study examined neurophysiological underpinnings of this effect. In a single-blinded within-subject design, we traced effects of A-tDCS compared to sham stimulation over the left…

Switchable capacitor

NARCIS (Netherlands)

Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, H.A.C.; Tilmans, Hendrikus; De Raedt, Walter

2011-01-01

A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom elecrode, a dielaectric layer deposited on at least part of sai bottum electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to the

Switchable capacitor

NARCIS (Netherlands)

Rottenberg, X.; Jansen, Henricus V.; Tilmans, H.A.C.; De Raedt, W.

2003-01-01

A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom elecrode, a dielaectric layer deposited on at least part of sai bottum electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to the

Treating Clinical Depression with Repetitive Deep Transcranial Magnetic Stimulation Using the Brainsway H1-coil.

Science.gov (United States)

Feifel, David; Pappas, Katherine

2016-10-04

Repetitive transcranial magnetic stimulation (rTMS) is an emerging non-pharmacological approach to treating many brain-based disorders. rTMS uses electromagnetic coils to stimulate areas of the brain non-invasively. Deep transcranial magnetic stimulation (dTMS) with the Brainsway H1-coil system specifically is a type of rTMS indicated for treating patients with major depressive disorder (MDD) who are resistant to medication. The unique H1-coil design of this device is able to stimulate neuronal pathways that lie deeper in the targeted brain areas than those reached by conventional rTMS coils. dTMS is considered to be low-risk and well tolerated, making it a viable treatment option for people who have not responded to medication or psychotherapy trials for their depression. Randomized, sham-control studies have demonstrated that dTMS produces significantly greater improvement in depressive symptoms than sham dTMS treatment in patients with major depression that has not responded to antidepressant medication. In this paper, we will review the methodology for treating major depression with dTMS using an H1-coil.

2000 survey of window manufacturers on the subject of switchable glass

Science.gov (United States)

LaPointe, Michael R.; Sottile, Gregory M.

2001-11-01

The results of a 2000 survey of United States window manufacturers on the subject of switchable glass are discussed. The areas covered in this paper include awareness of the overall product category of switchable glass and various types of switchable glass, attitudes toward specific features of switchable glass, expectations for manufacturer production of such products, expectations for market penetration rates among end-product consumers, levels of price sensitivity among window manufacturers regarding switchable glass, and expectations for the pace of new product development within the window industry over the next five years.

Efficacy of transcranial direct-current stimulation (tDCS) in women with provoked vestibulodynia: study protocol for a randomized controlled trial.

Science.gov (United States)

Morin, Annie; Léonard, Guillaume; Gougeon, Véronique; Waddell, Guy; Bureau, Yves-André; Girard, Isabelle; Morin, Mélanie

2016-05-14

Provoked vestibulodynia is the most common form of vulvodynia. Despite its high prevalence and deleterious sexual, conjugal, and psychological repercussions, effective evidence-based interventions for provoked vestibulodynia remain limited. For a high proportion of women, significant pain persists despite the currently available treatments. Growing evidence suggests that the central nervous system (CNS) could play a key role in provoked vestibulodynia; thus, treatment targeting the CNS, rather than localized dysfunctions, may be beneficial for women suffering from provoked vestibulodynia. In this study, we aim to build on the promising results of a previous case report and evaluate whether transcranial direct-current stimulation, a non-invasive brain stimulation technique targeting the CNS, could be an effective treatment option for women with provoked vestibulodynia. This single-center, triple-blind, parallel group, randomized, controlled trial aims to compare the efficacy of transcranial direct-current stimulation with sham transcranial direct-current stimulation in women with provoked vestibulodynia. Forty women diagnosed with provoked vestibulodynia by a gynecologist, following a standardized treatment protocol, are randomized to either active transcranial direct-current stimulation treatment for ten sessions of 20 minutes at an intensity of 2 mA or sham transcranial direct-current stimulation over a 2-week period. Outcome measures are collected at baseline, 2 weeks after treatment and at 3-month follow-up. The primary outcome is pain during intercourse, assessed with a numerical rating scale. Secondary measurements focus on the sexual function, vestibular pain sensitivity, psychological distress, treatment satisfaction, and the patient's global impression of change. To our knowledge, this study is the first randomized controlled trial to examine the efficacy of transcranial direct-current stimulation in women with provoked vestibulodynia. Findings from this

Effectiveness of anodal transcranial direct current stimulation in patients with chronic low back pain: Design, method and protocol for a randomised controlled trial

Directory of Open Access Journals (Sweden)

Luedtke Kerstin

2011-12-01

Full Text Available Abstract Background Electrical stimulation of central nervous system areas with surgically implanted stimulators has been shown to result in pain relief. To avoid the risks and side effects of surgery, transcranial direct current stimulation is an option to electrically stimulate the motor cortex through the skull. Previous research has shown that transcranial direct current stimulation relieves pain in patients with fibromyalgia, chronic neuropathic pain and chronic pelvic pain. Evidence indicates that the method is pain free, safe and inexpensive. Methods/Design A randomised controlled trial has been designed to evaluate the effect of transcranial direct current stimulation over the motor cortex for pain reduction in patients with chronic low back pain. It will also investigate whether transcranial direct current stimulation as a prior treatment enhances the symptom reduction achieved by a cognitive-behavioural group intervention. Participants will be randomised to receive a series of 5 days of transcranial direct current stimulation (2 mA, 20 mins or 20 mins of sham stimulation; followed by a cognitive-behavioural group programme. The primary outcome parameters will measure pain (Visual Analog Scale and disability (Oswestry Disability Index. Secondary outcome parameters will include the Fear Avoidance Beliefs Questionnaire, the Funktionsfragebogen Hannover (perceived function, Hospital Anxiety Depression Scale, bothersomeness and Health Related Quality of Life (SF 36, as well as Patient-Perceived Satisfactory Improvement. Assessments will take place immediately prior to the first application of transcranial direct current stimulation or sham, after 5 consecutive days of stimulation, immediately after the cognitive-behavioural group programme and at 4 weeks, 12 weeks and 24 weeks follow-up. Discussion This trial will help to determine, whether transcranial direct current stimulation is an effective treatment for patients with chronic low back

ANODAL TRANSCRANIAL DIRECT CURRENT STIMULATION (TDCS) INCREASES ISOMETRIC STRENGTH OF SHOULDER ROTATORS MUSCLES IN HANDBALL PLAYERS.

Science.gov (United States)

Hazime, Fuad Ahmad; da Cunha, Ronaldo Alves; Soliaman, Renato Rozenblit; Romancini, Ana Clara Bezerra; Pochini, Alberto de Castro; Ejnisman, Benno; Baptista, Abrahão Fontes

2017-06-01

Weakness of the rotator cuff muscles can lead to imbalances in the strength of shoulder external and internal rotators, change the biomechanics of the glenohumeral joint and predispose an athlete to injury. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has demonstrated promising results in a variety of health conditions. However few studies addressed its potential approach in the realm of athletics. The purpose of this study was to investigate if transcranial direct current stimulation (tDCS) technique increases the isometric muscle strength of shoulder external and internal rotators in handball athletes. Randomized, double-blind, placebo-controlled, crossover study. Eight female handball players aged between 17 and 21 years (Mean=19.65; SD=2.55) with 7.1 ± 4.8 years of experience in training, participating in regional and national competitions were recruited. Maximal voluntary isometric contraction (MVIC) of shoulder external and internal rotator muscles was evaluated during and after 30 and 60 minutes post one session of anodal and sham current (2mA; 0.057mA/cm 2 ) with a one-week interval between stimulations. Compared to baseline, MVIC of shoulder external and internal rotators significantly increased after real but not sham tDCS. Between-group differences were observed for external and internal rotator muscles. Maximal voluntary isometric contraction of external rotation increased significantly during tDCS, and 30 and 60 minutes post-tDCS for real tDCS compared to that for sham tDCS. For internal rotation MVIC increased significantly during and 60 minutes post-tDCS. The results indicate that transcranial direct current stimulation temporarily increases maximal isometric contractions of the internal and external rotators of the shoulder in handball players. 2.

Enhancing decision-making and cognitive impulse control with transcranial direct current stimulation (tDCS) applied over the orbitofrontal cortex (OFC): A randomized and sham-controlled exploratory study.

Science.gov (United States)

Ouellet, Julien; McGirr, Alexander; Van den Eynde, Frederique; Jollant, Fabrice; Lepage, Martin; Berlim, Marcelo T

2015-10-01

Decision-making and impulse control (both cognitive and motor) are complex interrelated processes which rely on a distributed neural network that includes multiple cortical and subcortical regions. Among them, the orbitofrontal cortex (OFC) seems to be particularly relevant as demonstrated by several neuropsychological and neuroimaging investigations. In the present study we assessed whether transcranial direct current stimulation (tDCS) applied bilaterally over the OFC is able to modulate decision-making and cognitive impulse control. More specifically, 45 healthy subjects were randomized to receive a single 30-min session of active or sham anodal tDCS (1.5 mA) applied over either the left or the right OFC (coupled with contralateral cathodal tDCS). They were also assessed pre- and post-tDCS with a battery of computerized tasks. Our results show that participants who received active anodal tDCS (irrespective of laterality), vs. those who received sham tDCS, displayed more advantageous decision-making (i.e., increased Iowa Gambling Task "net scores" [p = 0.04]), as well as improved cognitive impulse control (i.e., decreased "interference" in the Stroop Word-Colour Task [p = 0.007]). However, we did not observe tDCS-related effects on mood (assessed by visual analogue scales), attentional levels (assessed by the Continuous Performance Task) or motor impulse control (assessed by the Stop-Signal Task). Our study potentially serves as a key translational step towards the development of novel non-invasive neuromodulation-based therapeutic interventions directly targeting vulnerability factors for psychiatric conditions such as suicidal behaviour and addiction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transcranial direct current stimulation over left inferior frontal cortex improves speech fluency in adults who stutter.

Science.gov (United States)

Chesters, Jennifer; Möttönen, Riikka; Watkins, Kate E

2018-04-01

See Crinion (doi:10.1093/brain/awy075) for a scientific commentary on this article.Stuttering is a neurodevelopmental condition affecting 5% of children, and persisting in 1% of adults. Promoting lasting fluency improvement in adults who stutter is a particular challenge. Novel interventions to improve outcomes are of value, therefore. Previous work in patients with acquired motor and language disorders reported enhanced benefits of behavioural therapies when paired with transcranial direct current stimulation. Here, we report the results of the first trial investigating whether transcranial direct current stimulation can improve speech fluency in adults who stutter. We predicted that applying anodal stimulation to the left inferior frontal cortex during speech production with temporary fluency inducers would result in longer-lasting fluency improvements. Thirty male adults who stutter completed a randomized, double-blind, controlled trial of anodal transcranial direct current stimulation over left inferior frontal cortex. Fifteen participants received 20 min of 1-mA stimulation on five consecutive days while speech fluency was temporarily induced using choral and metronome-timed speech. The other 15 participants received the same speech fluency intervention with sham stimulation. Speech fluency during reading and conversation was assessed at baseline, before and after the stimulation on each day of the 5-day intervention, and at 1 and 6 weeks after the end of the intervention. Anodal stimulation combined with speech fluency training significantly reduced the percentage of disfluent speech measured 1 week after the intervention compared with fluency intervention alone. At 6 weeks after the intervention, this improvement was maintained during reading but not during conversation. Outcome scores at both post-intervention time points on a clinical assessment tool (the Stuttering Severity Instrument, version 4) also showed significant improvement in the group receiving

Effect of transcranial direct current stimulation (tDCS over the prefrontal cortex combined with cognitive training for treating schizophrenia: a sham-controlled randomized clinical trial

Directory of Open Access Journals (Sweden)

Pedro Shiozawa

Full Text Available Abstract Introduction: We report a transcranial direct current stimulation (tDCS protocol over the dorsolateral prefrontal cortex (DLPFC combined with cognitive training in schizophrenia. Method: We assessed psychotic symptoms in nine patients using the Positive and Negative Syndrome Scale (PANSS. All evaluations were scored at baseline, at the end of the intervention protocol, and during a 4-week follow-up. The tDCS protocol consisted of 10 consecutive sessions over 5-day periods. We placed the cathode over the right and the anode over the left DLPFC. For sham stimulation, we turned the device off after 60 seconds. Cognitive training consisted of the administration of N-back and sequence learning tasks. Results: We performed an analysis of covariance (ANCOVA to adjust for the dependent variable PANSS, considering the interaction with baseline severity scores (p = 0.619. Mixed analysis of variance (ANOVA showed no statistical significance between the groups regarding final PANSS scores. Conclusion: The results failed to demonstrate that the concomitant use of tDCS and cognitive training is effective to improve clinical outcomes in patients with schizophrenia. The present findings should be analyzed with care, considering the small sample size. Larger controlled trials on electric/cognitive stimulation should be produced in order to enhance therapeutic strategies in schizophrenia.

Enhancement of Cortical Excitability and Lower Limb Motor Function in Patients With Stroke by Transcranial Direct Current Stimulation.

Science.gov (United States)

Chang, Min Cheol; Kim, Dae Yul; Park, Dae Hwan

2015-01-01

Motor dysfunction in the lower limbs is a common sequela in stroke patients. We used transcranial magnetic stimulation (TMS) to determine if applying transcranial direct current stimulation (tDCS) to the primary motor cortex helps enhance cortical excitability. Furthermore, we evaluate if combination anodal tDCS and conventional physical therapy improves motor function in the lower limbs. Twenty-four patients with early-stage stroke were randomly assigned to 2 groups: 1) the tDCS group, in which patients received 10 sessions of anodal tDCS and conventional physical therapy; and 2) the sham group, in which patients received 10 sessions of sham stimulation and conventional physical therapy. One day before and after intervention, the motor-evoked potential (MEP) of the affected tibialis anterior muscle was evaluated and motor function was assessed using the lower limb subscale of the Fugl-Meyer Assessment (FMA-LE), lower limb Motricity Index (MI-LE), Functional Ambulatory Category (FAC), Berg Balance Scale (BBS), and gait analysis. The MEPs in the tDCS group became shorter in latency and higher in amplitude after intervention in comparison with the sham group. Improvements in FMA-LE and MI-LE were greater in the tDCS group, but no significant differences in FAC or BBS scores were found. Also, the changes observed on the gait analyses did not significantly differ between the tDCS and sham groups. Combination anodal tDCS and conservative physical therapy appears to be a beneficial therapeutic modality for improving motor function in the lower limbs in patients with subacute stroke. Copyright © 2015 Elsevier Inc. All rights reserved.

Polarity-Dependent Misperception of Subjective Visual Vertical during and after Transcranial Direct Current Stimulation (tDCS).

Science.gov (United States)

Santos-Pontelli, Taiza E G; Rimoli, Brunna P; Favoretto, Diandra B; Mazin, Suleimy C; Truong, Dennis Q; Leite, Joao P; Pontes-Neto, Octavio M; Babyar, Suzanne R; Reding, Michael; Bikson, Marom; Edwards, Dylan J

2016-01-01

Pathologic tilt of subjective visual vertical (SVV) frequently has adverse functional consequences for patients with stroke and vestibular disorders. Repetitive transcranial magnetic stimulation (rTMS) of the supramarginal gyrus can produce a transitory tilt on SVV in healthy subjects. However, the effect of transcranial direct current stimulation (tDCS) on SVV has never been systematically studied. We investigated whether bilateral tDCS over the temporal-parietal region could result in both online and offline SVV misperception in healthy subjects. In a randomized, sham-controlled, single-blind crossover pilot study, thirteen healthy subjects performed tests of SVV before, during and after the tDCS applied over the temporal-parietal region in three conditions used on different days: right anode/left cathode; right cathode/left anode; and sham. Subjects were blind to the tDCS conditions. Montage-specific current flow patterns were investigated using computational models. SVV was significantly displaced towards the anode during both active stimulation conditions when compared to sham condition. Immediately after both active conditions, there were rebound effects. Longer lasting after-effects towards the anode occurred only in the right cathode/left anode condition. Current flow models predicted the stimulation of temporal-parietal regions under the electrodes and deep clusters in the posterior limb of the internal capsule. The present findings indicate that tDCS over the temporal-parietal region can significantly alter human SVV perception. This tDCS approach may be a potential clinical tool for the treatment of SVV misperception in neurological patients.

Delayed enhancement of multitasking performance: Effects of anodal transcranial direct current stimulation on the prefrontal cortex.

Science.gov (United States)

Hsu, Wan-Yu; Zanto, Theodore P; Anguera, Joaquin A; Lin, Yung-Yang; Gazzaley, Adam

2015-08-01

The dorsolateral prefrontal cortex (DLPFC) has been proposed to play an important role in neural processes that underlie multitasking performance. However, this claim is underexplored in terms of direct causal evidence. The current study aimed to delineate the causal involvement of the DLPFC during multitasking by modulating neural activity with transcranial direct current stimulation (tDCS) prior to engagement in a demanding multitasking paradigm. The study is a single-blind, crossover, sham-controlled experiment. Anodal tDCS or sham tDCS was applied over left DLPFC in forty-one healthy young adults (aged 18-35 years) immediately before they engaged in a 3-D video game designed to assess multitasking performance. Participants were separated into three subgroups: real-sham (i.e., real tDCS in the first session, followed by sham tDCS in the second session 1 h later), sham-real (sham tDCS first session, real tDCS second session), and sham-sham (sham tDCS in both sessions). The real-sham group showed enhanced multitasking performance and decreased multitasking cost during the second session, compared to first session, suggesting delayed cognitive benefits of tDCS. Interestingly, performance benefits were observed only for multitasking and not on a single-task version of the game. No significant changes were found between the first and second sessions for either the sham-real or the sham-sham groups. These results suggest a causal role of left prefrontal cortex in facilitating the simultaneous performance of more than one task, or multitasking. Moreover, these findings reveal that anodal tDCS may have delayed benefits that reflect an enhanced rate of learning. Copyright © 2015 Elsevier Ltd. All rights reserved.

Partial clinical response to 2 weeks of 2 Hz repetitive transcranial magnetic stimulation to the right parietal cortex in depression

NARCIS (Netherlands)

Schutter, D.J.L.G.; Laman, D.M.; Honk, E.J. van; Vergouwen, A.C.M.; Koerselman, F.

2009-01-01

The aim of this treatment study was to evaluate the therapeutic effects of repetitive transcranial magnetic stimulation (rTMS) over the right parietal cortex in depression. In a double-blind, sham-controlled design ten consecutive sessions of 2 Hz rTMS (inter-pulse interval 0.5 s) at 90% motor

The effect of dual-hemisphere transcranial direct current stimulation over the parietal operculum on tactile orientation discrimination

DEFF Research Database (Denmark)

Fujimoto, Shuhei; Tanaka, Satoshi; Laakso, Ilkka

2017-01-01

The parietal operculum (PO) often shows ipsilateral activation during tactile object perception in neuroimaging experiments. However, the relative contribution of the PO to tactile judgment remains unclear. Here, we examined the effect of transcranial direct current stimulation (tDCS) over...... bilateral PO to test the relative contributions of the ipsilateral PO to tactile object processing. Ten healthy adults participated in this study, which had a double-blind, sham-controlled, cross-over design. Participants discriminated grating orientation during three tDCS and sham conditions. In the dual......-hemisphere tDCS conditions, anodal and cathodal electrodes were placed over the left and right PO. In the uni-hemisphere tDCS condition, anodal and cathodal electrodes were applied over the left PO and contralateral orbit, respectively. In the tDCS and sham conditions, we applied 2 mA for 15 min and for 15 s...

Long term clinical and neurophysiological effects of cerebellar transcranial direct current stimulation in patients with neurodegenerative ataxia.

Science.gov (United States)

Benussi, Alberto; Dell'Era, Valentina; Cotelli, Maria Sofia; Turla, Marinella; Casali, Carlo; Padovani, Alessandro; Borroni, Barbara

Neurodegenerative cerebellar ataxias represent a group of disabling disorders for which we currently lack effective therapies. Cerebellar transcranial direct current stimulation (tDCS) is a non-invasive technique, which has been demonstrated to modulate cerebellar excitability and improve symptoms in patients with cerebellar ataxias. The present study investigated whether a two-weeks' treatment with cerebellar anodal tDCS could improve symptoms in patients with neurodegenerative cerebellar ataxia and could modulate cerebello-motor connectivity, at short and long term. We performed a double-blind, randomized, sham controlled trial with cerebellar tDCS (5 days/week for 2 weeks) in twenty patients with ataxia. Each patient underwent a clinical evaluation pre- and post-anodal tDCS or sham stimulation. A follow-up evaluation was performed at one and three months. Cerebello-motor connectivity was evaluated using transcranial magnetic stimulation (TMS) at baseline and at follow-up. Patients who underwent anodal tDCS showed a significant improvement in all performance scores (scale for the assessment and rating of ataxia, international cooperative ataxia rating scale, 9-hole peg test, 8-m walking time) and in cerebellar brain inhibition compared to patients who underwent sham stimulation. A two-weeks' treatment with anodal cerebellar tDCS improves symptoms in patients with ataxia and restores physiological cerebellar brain inhibition pathways. Cerebellar tDCS might represent a promising future therapeutic and rehabilitative approach in patients with neurodegenerative ataxia. Copyright © 2016 Elsevier Inc. All rights reserved.

Switchable Hydrophobic-Hydrophilic Surfaces

CERN Document Server

Bunker, B C; Huber, D L; Kent, M S; Kushmerick, J G; Lopez, G P; Manginell, R P; Méndez, S E; Yim, H

2002-01-01

Tethered films of poly n-isopropylacrylamide (PNIPAM) films have been developed as materials that can be used to switch the chemistry of a surface in response to thermal activation. In water, PNIPAM exhibits a thermally-activated phase transition that is accompanied by significant changes in polymer volume, water contact angle, and protein adsorption characteristics. New synthesis routes have been developed to prepare PNIPAM films via in-situ polymerization on self-assembled monolayers. Swelling transitions in tethered films have been characterized using a wide range of techniques including surface plasmon resonance, attenuated total reflectance infrared spectroscopy, interfacial force microscopy, neutron reflectivity, and theoretical modeling. PNIPAM films have been deployed in integrated microfluidic systems. Switchable PNIPAM films have been investigated for a range of fluidic applications including fluid pumping via surface energy switching and switchable protein traps for pre-concentrating and separating...

Preoperative transcranial direct current stimulation: Exploration of a novel strategy to enhance neuroplasticity before surgery to control postoperative pain. A randomized sham-controlled study.

Directory of Open Access Journals (Sweden)

Hugo Ribeiro

Full Text Available An imbalance in the excitatory/inhibitory systems in the pain networks may explain the persistent chronic pain after hallux valgus surgery. Thus, to contra-regulate this dysfunction, the use of transcranial direct current stimulation (tDCS becomes attractive.We tested the hypothesis that two preoperative active(a-tDCS sessions compared with sham(s-tDCS could improve the postoperative pain [as indexed by Visual Analogue Scale (VAS at rest and during walking (primary outcomes]. To assess their effect on the change in the Numerical Pain Scale (NPS0-10 during Conditioned Pain Modulation (CPM-task, disability related to pain (DRP and analgesic consumption (secondary outcomes. Also, we assessed if the brain derived neurotrophic factor (BDNF in the cerebral spinal fluid (CSF after tDCS could predict the intervention's effect on the DRP.It is a prospective, double blind, sham-controlled, randomized single center, 40 women (18-70 years-old who had undergone hallux valgus surgery were randomized to receive two sessions (20 minutes each of anodal a-tDCS or s-tDCS on the primary motor cortex at night and in the morning before the surgery. To assess the DRP was used the Brazilian Profile of Chronic Pain: Screen (B-PCP:S.A-tDCS group showed lower scores on VAS at rest and during walking (P<0.001. At rest, the difference between groups was 2.13cm (95%CI = 1.59 to 2.68 while during walking was 1.67cm (95%CI = 1.05 to 2.28. A-tDCS, when compared to s-tDCS reduced analgesic doses in 73.25% (P<0.001, produced a greater reduction in B-PCP:S (mean difference of 9.41 points, 95%CI = 0.63 to 18.21 and higher function of descending pain modulatory system (DPMS during CPM-task.A-tDCS improves postoperative pain, the DRP and the function of DPMS. Also, the CSF BDNF after a-tDCS predicted the improvement in the DRP. In overall, these findings suggest that a-tDCS effects may be mediated by top-down regulatory mechanisms associated with the inhibitory cortical control

Transcranial direct current stimulation does not affect lower extremity muscle strength training in healthy individuals

DEFF Research Database (Denmark)

Maeda, Kazuhei; Yamaguchi, Tomofumi; Tatemoto, Tsuyoshi

2017-01-01

The present study investigated the effects of anodal transcranial direct current stimulation (tDCS) on lower extremity muscle strength training in 24 healthy participants. In this triple-blind, sham-controlled study, participants were randomly allocated to the anodal tDCS plus muscle strength...... training (anodal tDCS) group or sham tDCS plus muscle strength training (sham tDCS) group. Anodal tDCS (2 mA) was applied to the primary motor cortex of the lower extremity during muscle strength training of the knee extensors and flexors. Training was conducted once every 3 days for 3 weeks (7 sessions......). Knee extensor and flexor peak torques were evaluated before and after the 3 weeks of training. After the 3-week intervention, peak torques of knee extension and flexion changed from 155.9 to 191.1 Nm and from 81.5 to 93.1 Nm in the anodal tDCS group. Peak torques changed from 164.1 to 194.8 Nm...

Effect of Transcranial Direct Current Stimulation on Severely Affected Arm-Hand Motor Function in Patients After an Acute Ischemic Stroke: A Pilot Randomized Control Trial.

Science.gov (United States)

Rabadi, Meheroz H; Aston, Christopher E

2017-10-01

The aim of this article was to determine whether cathodal transcranial direct current stimulation (c-tDCS) to unaffected primary motor cortex (PMC) plus conventional occupational therapy (OT) improves functional motor recovery of the affected arm hand in patients after an acute ischemic stroke compared with sham transcranial direct current stimulation plus conventional OT. In this prospective, randomized, double-blinded, sham-controlled trial of 16 severe, acute ischemic stroke patients with severe arm-hand weakness were randomly assigned to either experimental (c-tDCS plus OT; n = 8) or control (sham transcranial direct current stimulation plus OT; n = 8) groups. All patients received a standard 3-hr in-patient rehabilitation therapy, plus an additional ten 30-min sessions of tDCS. During each session, 1 mA of cathodal stimulation to the unaffected PMC is performed followed by the patient's scheduled OT. The primary outcome measure was change in Action Research Arm Test (ARAT) total and subscores on discharge. Application of c-tDCS to unaffected PMC resulted in a clinically relevant 10-point improvement in the affected arm-hand function based on ARAT total score compared with a 2-point improvement in the control group. Application of 30-min of c-tDCS to the unaffected PMC showed a 10-point improvement in the ARAT score. This corresponds to a large effect size in improvement of affected arm-hand function in patients with severe, acute ischemic stroke. Although not statistically significant, this suggests that larger studies, enrolling at least 25 patients in each group, and with a longer follow-up are warranted.

Transcranial direct current stimulation reduces food-craving and measures of hyperphagia behavior in participants with Prader-Willi syndrome.

Science.gov (United States)

Bravo, Gabriela L; Poje, Albert B; Perissinotti, Iago; Marcondes, Bianca F; Villamar, Mauricio F; Manzardo, Ann M; Luque, Laura; LePage, Jean F; Stafford, Diane; Fregni, Felipe; Butler, Merlin G

2016-03-01

Prader-Willi syndrome (PWS) is a neurodevelopmental genetic disorder characterized by intellectual disabilities and insatiable appetite with compulsive eating leading to severe obesity with detrimental health consequences. Transcranial direct current stimulation (tDCS) has been shown to modulate decision-making and cue-induced food craving in healthy adults. We conducted a pilot double blind, sham-controlled, multicenter study of tDCS modulation of food drive and craving in 10 adult PWS participants, 11 adult obese (OB) and 11 adult healthy-weight control (HWC) subjects. PWS and OB subjects received five consecutive daily sessions of active or sham tDCS over the right dorsolateral prefrontal cortex (DLPFC), while HWC received a single sham and active tDCS in a crossover design. Standardized psychometric instruments assessed food craving, drive and hyperphagia by self-report and caregiver assessment over 30 days. Robust baseline differences were observed in severity scores for the Three-Factor Eating Questionnaire (TFEQ) and Dykens Hyperphagia Questionnaire (DHQ) for PWS compared to HWC while obese participants were more similar to HWC. Active tDCS stimulation in PWS was associated with a significant change from baseline in TFEQ Disinhibition (Factor II) (Ƶ = 1.9, P food drive and behaviors impacting hyperphagia in PWS. Transcranial direct current stimulation may represent a straight-forward, low risk and low cost method to improve care, management and quality of life in PWS. © 2015 Wiley Periodicals, Inc.

The efficacy of transcranial magnetic stimulation on migraine: a meta-analysis of randomized controlled trails.

Science.gov (United States)

Lan, Lihuan; Zhang, Xiaoni; Li, Xiangpen; Rong, Xiaoming; Peng, Ying

2017-08-22

As a non-invasive therapy, whether transcranial magnetic stimulation (TMS) is effective on migraine. This article was aimed to assess the efficacy of TMS on migraine based on randomized controlled trails (RCTs). We searched PubMed, Embase and Cochrane Library electronic databases for published studies which compared TMS group with sham group, conducted a meta-analysis of all RCTs. Five studies, consisting of 313 migraine patients, were identified. Single-pulse transcranial magnetic stimulation is effective for the acute treatment of migraine with aura after the first attack (p = 0.02). And, the efficacy of TMS on chronic migraine was not significant (OR 2.93; 95% CI 0.71-12.15; p = 0.14). TMS is effective for migraine based on the studies included in the article.

The Effects of Transcranial Direct Current Stimulation (tDCS on Multitasking Throughput Capacity

Directory of Open Access Journals (Sweden)

Justin Nelson

2016-11-01

Full Text Available Background: Multitasking has become an integral attribute associated with military operations within the past several decades. As the amount of information that needs to be processed during these high level multitasking environments exceeds the human operators’ capabilities, the information throughput capacity reaches an asymptotic limit. At this point, the human operator can no longer effectively process and respond to the incoming information resulting in a plateau or decline in performance. The objective of the study was to evaluate the efficacy of a non-invasive brain stimulation technique known as transcranial direct current stimulation (tDCS applied to a scalp location over the left dorsolateral prefrontal cortex (lDLPFC to improve information processing capabilities during a multitasking environment. Methods: The study consisted of 20 participants from Wright-Patterson Air Force Base (16 male and 4 female with an average age of 31.1 (SD = 4.5. Participants were randomly assigned into two groups, each consisting of eight males and two females. Group one received 2mA of anodal tDCS and group two received sham tDCS over the lDLPFC on their testing day. Results: The findings indicate that anodal tDCS significantly improves the participants’ information processing capability resulting in improved performance compared to sham tDCS. For example, the multitasking throughput capacity for the sham tDCS group plateaued near 1.0 bits/s at the higher baud input (2.0 bits/s whereas the anodal tDCS group plateaued near 1.3 bits/s. Conclusion: The findings provided new evidence that tDCS has the ability to augment and enhance multitasking capability in a human operator. Future research should be conducted to determine the longevity of the enhancement of transcranial direct current stimulation on multitasking performance, which has yet to be accomplished.

The Effects of Transcranial Direct Current Stimulation (tDCS) on Multitasking Throughput Capacity.

Science.gov (United States)

Nelson, Justin; McKinley, Richard A; Phillips, Chandler; McIntire, Lindsey; Goodyear, Chuck; Kreiner, Aerial; Monforton, Lanie

2016-01-01

Background: Multitasking has become an integral attribute associated with military operations within the past several decades. As the amount of information that needs to be processed during these high level multitasking environments exceeds the human operators' capabilities, the information throughput capacity reaches an asymptotic limit. At this point, the human operator can no longer effectively process and respond to the incoming information resulting in a plateau or decline in performance. The objective of the study was to evaluate the efficacy of a non-invasive brain stimulation technique known as transcranial direct current stimulation (tDCS) applied to a scalp location over the left dorsolateral prefrontal cortex (lDLPFC) to improve information processing capabilities during a multitasking environment. Methods: The study consisted of 20 participants from Wright-Patterson Air Force Base (16 male and 4 female) with an average age of 31.1 (SD = 4.5). Participants were randomly assigned into two groups, each consisting of eight males and two females. Group one received 2 mA of anodal tDCS and group two received sham tDCS over the lDLPFC on their testing day. Results: The findings indicate that anodal tDCS significantly improves the participants' information processing capability resulting in improved performance compared to sham tDCS. For example, the multitasking throughput capacity for the sham tDCS group plateaued near 1.0 bits/s at the higher baud input (2.0 bits/s) whereas the anodal tDCS group plateaued near 1.3 bits/s. Conclusion: The findings provided new evidence that tDCS has the ability to augment and enhance multitasking capability in a human operator. Future research should be conducted to determine the longevity of the enhancement of transcranial direct current stimulation on multitasking performance, which has yet to be accomplished.

1-Hz rTMS in the treatment of tinnitus: A sham-controlled, randomized multicenter trial.

Science.gov (United States)

Landgrebe, Michael; Hajak, Göran; Wolf, Stefan; Padberg, Frank; Klupp, Philipp; Fallgatter, Andreas J; Polak, Thomas; Höppner, Jacqueline; Haker, Rene; Cordes, Joachim; Klenzner, Thomas; Schönfeldt-Lecuona, Carlos; Kammer, Thomas; Graf, Erika; Koller, Michael; Kleinjung, Tobias; Lehner, Astrid; Schecklmann, Martin; Pöppl, Timm B; Kreuzer, Peter; Frank, Elmar; Langguth, Berthold

Chronic tinnitus is a frequent, difficult to treat disease with high morbidity. This multicenter randomized, sham-controlled trial investigated the efficacy and safety of 1-Hz repetitive transcranial magnetic stimulation (rTMS) applied to the left temporal cortex in patients with chronic tinnitus. Tinnitus patients were randomized to receive 10 sessions of either real or sham 1-Hz-rTMS (2000 stimuli, 110% motor threshold) to the left temporal cortex. The primary outcome was the change in the sum score of the tinnitus questionnaire (TQ) of Goebel and Hiller from baseline to end of treatment. A total of 163 patients were enrolled in the study (real rTMS: 75; sham rTMS: 78). At day 12, the baseline mean of 43.1 TQ points in 71 patients assigned to real rTMS changed by -0.5 points; it changed by 0.5 points from a baseline of 42.1 in 75 patients randomized to sham rTMS (adjusted mean difference between groups: -1.0; 95.19% confidence interval: -3.2 to 1.2; p = 0.36). All secondary outcome measures including measures of depression and quality of life showed no significant differences either (p > 0.11). The number of participants with side-effects or adverse events did not differ between groups. Real 1-Hz-rTMS over the left temporal cortex was well tolerated but not superior compared with sham rTMS in improving tinnitus severity. These findings are in contrast to results from studies with smaller sample sizes and put the efficacy of this rTMS protocol for treatment of chronic tinnitus into question. Controlled Trials: http://www.isrctn.com/ISRCTN89848288. Copyright © 2017 Elsevier Inc. All rights reserved.

Repetitive transcranial magnetic stimulation over the right dorsolateral prefrontal cortex affects strategic decision-making.

Science.gov (United States)

van 't Wout, Mascha; Kahn, René S; Sanfey, Alan G; Aleman, André

2005-11-07

Although decision-making is typically seen as a rational process, emotions play a role in tasks that include unfairness. Recently, activation in the right dorsolateral prefrontal cortex during offers experienced as unfair in the Ultimatum Game was suggested to subserve goal maintenance in this task. This is restricted to correlational evidence, however, and it remains unclear whether the dorsolateral prefrontal cortex is crucial for strategic decision-making. The present study used repetitive transcranial magnetic stimulation in order to investigate the causal role of the dorsolateral prefrontal cortex in strategic decision-making in the Ultimatum Game. The results showed that repetitive transcranial magnetic stimulation over the right dorsolateral prefrontal cortex resulted in an altered decision-making strategy compared with sham stimulation. We conclude that the dorsolateral prefrontal cortex is causally implicated in strategic decision-making in healthy human study participants.

Modulation of Illusory Auditory Perception by Transcranial Electrical Stimulation

Directory of Open Access Journals (Sweden)

Giulia Prete

2017-06-01

Full Text Available The aim of the present study was to test whether transcranial electrical stimulation can modulate illusory perception in the auditory domain. In two separate experiments we applied transcranial Direct Current Stimulation (anodal/cathodal tDCS, 2 mA; N = 60 and high-frequency transcranial Random Noise Stimulation (hf-tRNS, 1.5 mA, offset 0; N = 45 on the temporal cortex during the presentation of the stimuli eliciting the Deutsch's illusion. The illusion arises when two sine tones spaced one octave apart (400 and 800 Hz are presented dichotically in alternation, one in the left and the other in the right ear, so that when the right ear receives the high tone, the left ear receives the low tone, and vice versa. The majority of the population perceives one high-pitched tone in one ear alternating with one low-pitched tone in the other ear. The results revealed that neither anodal nor cathodal tDCS applied over the left/right temporal cortex modulated the perception of the illusion, whereas hf-tRNS applied bilaterally on the temporal cortex reduced the number of times the sequence of sounds is perceived as the Deutsch's illusion with respect to the sham control condition. The stimulation time before the beginning of the task (5 or 15 min did not influence the perceptual outcome. In accordance with previous findings, we conclude that hf-tRNS can modulate auditory perception more efficiently than tDCS.

Cerebellar transcranial static magnetic field stimulation transiently reduces cerebellar brain inhibition.

Science.gov (United States)

Matsugi, Akiyoshi; Okada, Y

The aim of this study was to investigate whether transcranial static magnetic field stimulation (tSMS) delivered using a compact cylindrical NdFeB magnet over the cerebellum modulates the excitability of the cerebellum and contralateral primary motor cortex, as measured using cerebellar brain inhibition (CBI), motor evoked potentials (MEPs), and resting motor threshold (rMT). These parameters were measured before tSMS or sham stimulation and immediately, 5 minutes and 10 minutes after stimulation. There were no significant changes in CBI, MEPs or rMT over time in the sham stimulation condition, and no changes in MEPs or rMT in the tSMS condition. However, CBI was significantly decreased immediately after tSMS as compared to that before and 5 minutes after tSMS. Our results suggest that tSMS delivered to the cerebellar hemisphere transiently reduces cerebellar inhibitory output but does not affect the excitability of the contralateral motor cortex.

Transcranial direct current stimulation over the parietal cortex alters bias in item and source memory tasks.

Science.gov (United States)

Pergolizzi, Denise; Chua, Elizabeth F

2016-10-01

Neuroimaging data have shown that activity in the lateral posterior parietal cortex (PPC) correlates with item recognition and source recollection, but there is considerable debate about its specific contributions. Performance on both item and source memory tasks were compared between participants who were given bilateral transcranial direct current stimulation (tDCS) over the parietal cortex to those given prefrontal or sham tDCS. The parietal tDCS group, but not the prefrontal group, showed decreased false recognition, and less bias in item and source discrimination tasks compared to sham stimulation. These results are consistent with a causal role of the PPC in item and source memory retrieval, likely based on attentional and decision-making biases. Copyright © 2016 Elsevier Inc. All rights reserved.

Transcranial direct current stimulation in refractory continuous spikes and waves during slow sleep: a controlled study

DEFF Research Database (Denmark)

Varga, Edina T; Terney, Daniella; Atkins, Mary D

2011-01-01

Cathodal transcranial direct current stimulation (tDCS) decreases cortical excitability. The purpose of the study was to investigate whether cathodal tDCS could interrupt the continuous epileptiform activity. Five patients with focal, refractory continuous spikes and waves during slow sleep were...... recruited. Cathodal tDCS and sham stimulation were applied to the epileptic focus, before sleep (1 mA; 20 min). Cathodal tDCS did not reduce the spike-index in any of the patients....

Transcranial infrared laser stimulation improves rule-based, but not information-integration, category learning in humans.

Science.gov (United States)

Blanco, Nathaniel J; Saucedo, Celeste L; Gonzalez-Lima, F

2017-03-01

This is the first randomized, controlled study comparing the cognitive effects of transcranial laser stimulation on category learning tasks. Transcranial infrared laser stimulation is a new non-invasive form of brain stimulation that shows promise for wide-ranging experimental and neuropsychological applications. It involves using infrared laser to enhance cerebral oxygenation and energy metabolism through upregulation of the respiratory enzyme cytochrome oxidase, the primary infrared photon acceptor in cells. Previous research found that transcranial infrared laser stimulation aimed at the prefrontal cortex can improve sustained attention, short-term memory, and executive function. In this study, we directly investigated the influence of transcranial infrared laser stimulation on two neurobiologically dissociable systems of category learning: a prefrontal cortex mediated reflective system that learns categories using explicit rules, and a striatally mediated reflexive learning system that forms gradual stimulus-response associations. Participants (n=118) received either active infrared laser to the lateral prefrontal cortex or sham (placebo) stimulation, and then learned one of two category structures-a rule-based structure optimally learned by the reflective system, or an information-integration structure optimally learned by the reflexive system. We found that prefrontal rule-based learning was substantially improved following transcranial infrared laser stimulation as compared to placebo (treatment X block interaction: F(1, 298)=5.117, p=0.024), while information-integration learning did not show significant group differences (treatment X block interaction: F(1, 288)=1.633, p=0.202). These results highlight the exciting potential of transcranial infrared laser stimulation for cognitive enhancement and provide insight into the neurobiological underpinnings of category learning. Copyright © 2017 Elsevier Inc. All rights reserved.

Electrically Reversible Redox-Switchable Polydopamine Films for Regulating Cell Behavior

International Nuclear Information System (INIS)

Tan, Guoxin; Liu, Yan; Wu, Yuxuan; Ouyang, Kongyou; Zhou, Lei; Yu, Peng; Liao, Jinwen; Ning, Chengyun

2017-01-01

Highlights: • The phenolic/quinone groups on polydopamine can redox-switchable reversible under electrical stimulation. • The quinone groups on PDA (oxidized PDA) enhanced cell spreading and proliferation. • The phenolic groups on PDA (reduced PDA) induced cell differentiation. - Abstract: Switchable surfaces that respond to external stimuli are important for regulating cell behavior. The results herein suggest that the redox process of polydopamine (PDA) is a switching reaction between oxidized polydopamine and reduced polydopamine, involving an interconversion of coupled two-proton (2H + ) and two-electron (2e − ) processes. The redox-switchable reversible surface potential arising from the potential-tunable redox reaction of the phenolic and quinone groups on PDA on titanium induced both cell adhesion and spreading. In vitro experiments demonstrated that the quinone groups on PDA greatly enhanced pre-osteoblasts MC3T3-E1 cell spreading and proliferation. Phenolic groups enhanced the induction of differentiation. The proposed methodology may allow further investigation of switchable surfaces for biological and medical applications.

Is the human mirror neuron system plastic? Evidence from a transcranial magnetic stimulation study.

Science.gov (United States)

Mehta, Urvakhsh Meherwan; Waghmare, Avinash V; Thirthalli, Jagadisha; Venkatasubramanian, Ganesan; Gangadhar, Bangalore N

2015-10-01

Virtual lesions in the mirror neuron network using inhibitory low-frequency (1Hz) transcranial magnetic stimulation (TMS) have been employed to understand its spatio-functional properties. However, no studies have examined the influence of neuro-enhancement by using excitatory high-frequency (20Hz) repetitive transcranial magnetic stimulation (HF-rTMS) on these networks. We used three forms of TMS stimulation (HF-rTMS, single and paired pulse) to investigate whether the mirror neuron system facilitates the motor system during goal-directed action observation relative to inanimate motion (motor resonance), a marker of putative mirror neuron activity. 31 healthy individuals were randomized to receive single-sessions of true or sham HF-rTMS delivered to the left inferior frontal gyrus - a component of the human mirror system. Motor resonance was assessed before and after HF-rTMS using three TMS cortical reactivity paradigms: (a) 120% of resting motor threshold (RMT), (b) stimulus intensity set to evoke motor evoked potential of 1-millivolt amplitude (SI1mV) and (c) a short latency paired pulse paradigm. Two-way RMANOVA showed a significant group (true versus sham) X occasion (pre- and post-HF-rTMS motor resonance) interaction effect for SI1mV [F(df)=6.26 (1, 29), p=0.018] and 120% RMT stimuli [F(df)=7.01 (1, 29), p=0.013] indicating greater enhancement of motor resonance in the true HF-rTMS group than the sham-group. This suggests that HF-rTMS could adaptively modulate properties of the mirror neuron system. This neuro-enhancement effect is a preliminary step that can open translational avenues for novel brain stimulation therapeutics targeting social-cognition deficits in schizophrenia and autism. Copyright © 2015 Elsevier B.V. All rights reserved.

Transcranial direct current stimulation for depression in Alzheimer's disease: study protocol for a randomized controlled trial.

Science.gov (United States)

Narita, Zui; Yokoi, Yuma

2017-06-19

Patients with Alzheimer's disease frequently elicit neuropsychiatric symptoms as well as cognitive deficits. Above all, depression is one of the most common neuropsychiatric symptoms in Alzheimer's disease but antidepressant drugs have not shown significant beneficial effects on it. Moreover, electroconvulsive therapy has not ensured its safety for potential severe adverse events although it does show beneficial clinical effect. Transcranial direct current stimulation can be the safe alternative of neuromodulation, which applies weak direct electrical current to the brain. Although transcranial direct current stimulation has plausible evidence for its effect on depression in young adult patients, no study has explored it in older subjects with depression in Alzheimer's disease. Therefore, we present a study protocol designed to evaluate the safety and clinical effect of transcranial direct current stimulation on depression in Alzheimer's disease in subjects aged over 65 years. This is a two-arm, parallel-design, randomized controlled trial, in which patients and assessors will be blinded. Subjects will be randomized to either an active or a sham transcranial direct current stimulation group. Participants in both groups will be evaluated at baseline, immediately, and 2 weeks after the intervention. This study investigates the safety and effect of transcranial direct current stimulation that may bring a significant impact on both depression and cognition in patients with Alzheimer's disease, and may be useful to enhance their quality of life. ClinicalTrials.gov, NCT02351388 . Registered on 27 January 2015. Last updated on 30 May 2016.

Transcranial Magnetic Stimulation in the Treatment of Chronic Widespread Pain: A Randomized, Controlled Study

Science.gov (United States)

Avery, David H.; Zarkowski, Paul; Krashin, Daniel; Rho, Wang-ku; Wajdik, Chandra; Joesch, Jutta M.; Haynor, David R.; Buchwald, Dedra; Roy-Byrne, Peter

2014-01-01

Objective Our objective was to assess transcranial magnetic stimulation (TMS) in the treatment of chronic widespread pain (CWP). Methods Nineteen participants were randomized to two groups: one receiving active TMS (N=7) and another receiving sham stimulation (N=11) applied to the left dorsolateral prefrontal cortex. During sham stimulation, subjects heard a sound similar to the sound heard by those receiving the active treatment and received an active electrical stimulus to the scalp. The stimulation protocol consisted of 15 sessions completed within a 4-week period. Blind assessments were done at baseline and after each 5 sessions followed by blind assessments at 1 week, 1 month and 3 months after the last TMS sessions. The primary outcome variable was a pain measure, the Gracely Box Intensity Scale (BIRS). Results The percentage of subjects who guessed that they were receiving TMS was similar in the two groups. Both the TMS group and the sham group showed a statistically significant reduction in the BIRS scores from baseline during the acute phase of treatment and the follow-up phase. However, the TMS and sham groups did not differ in the change in the BIRS scores. Discussion Although some previous clinical studies and basic science studies of TMS in treating pain are promising, this study found no difference in the analgesic effect of TMS and sham stimulation. Future studies should utilize a sham condition that attempts to simulate the sound and sensation of the TMS stimulation. Stimulus location and other stimulus parameters should be explored in future studies. PMID:24755729

Transcranial magnetic stimulation in the treatment of chronic widespread pain: a randomized controlled study.

Science.gov (United States)

Avery, David H; Zarkowski, Paul; Krashin, Daniel; Rho, Wang-Ku; Wajdik, Chandra; Joesch, Jutta M; Haynor, David R; Buchwald, Dedra; Roy-Byrne, Peter

2015-03-01

Our objective was to assess transcranial magnetic stimulation (TMS) in the treatment of chronic widespread pain. Nineteen participants were randomized into 2 groups: one group receiving active TMS (n = 7) and another group receiving sham stimulation (n = 11) applied to the left dorsolateral prefrontal cortex. During sham stimulation, subjects heard a sound similar to the sound heard by those receiving the active treatment and received an active electrical stimulus to the scalp. The stimulation protocol consisted of 15 sessions completed within a 4-week period. Blind assessments were done at baseline and after each 5 sessions followed by blind assessments at 1 week, 1 month, and 3 months after the last TMS sessions. The primary outcome variable was a pain measure, the Gracely Box Intensity Scale (BIRS). The percentage of subjects who guessed that they were receiving TMS was similar in the 2 groups. Both the TMS group and the sham group showed a statistically significant reduction in the BIRS scores from baseline during the acute phase of treatment and the follow-up phase. However, the TMS and sham groups did not differ in the change in the BIRS scores. Although some previous clinical studies and basic science studies of TMS in treating pain are promising, this study found no difference in the analgesic effect of TMS and sham stimulation. Future studies should use a sham condition that attempts to simulate the sound and sensation of the TMS stimulation. Stimulus location and other stimulus parameters should be explored in future studies.

Modulation of Somatosensory Alpha Rhythm by Transcranial Alternating Current Stimulation at Mu-Frequency

Directory of Open Access Journals (Sweden)

Christopher Gundlach

2017-08-01

Full Text Available Introduction: Transcranial alternating current stimulation (tACS is emerging as an interventional tool to modulate different functions of the brain, potentially by interacting with intrinsic ongoing neuronal oscillations. Functionally different intrinsic alpha oscillations are found throughout the cortex. Yet it remains unclear whether tACS is capable of specifically modulating the somatosensory mu-rhythm in amplitude.Objectives: We used tACS to modulate mu-alpha oscillations in amplitude. When compared to sham stimulation we expected a modulation of mu-alpha oscillations but not visual alpha oscillations by tACS.Methods: Individual mu-alpha frequencies were determined in 25 participants. Subsequently, blocks of tACS with individual mu-alpha frequency and sham stimulation were applied over primary somatosensory cortex (SI. Electroencephalogram (EEG was recorded before and after either stimulation or sham. Modulations of mu-alpha and, for control, visual alpha amplitudes were then compared between tACS and sham.Results: Somatosensory mu-alpha oscillations decreased in amplitude after tACS was applied at participants’ individual mu-alpha frequency. No changes in amplitude were observed for sham stimulation. Furthermore, visual alpha oscillations were not affected by tACS or sham, respectively.Conclusion: Our results demonstrate the capability of tACS to specifically modulate the targeted somatosensory mu-rhythm when the tACS frequency is tuned to the individual endogenous rhythm and applied over somatosensory areas. Our results are in contrast to previously reported amplitude increases of visual alpha oscillations induced by tACS applied over visual cortex. Our results may point to a specific interaction between our stimulation protocol and the functional architecture of the somatosensory system.

Block copolymer micelles as switchable templates for nanofabrication

OpenAIRE

Krishnamoorthy, S; Pugin, R; Brugger, J; Heinzelmann, H; Hoogerwerf, A C; Hinderling, C

2006-01-01

Block copolymer inverse micelles from polystyrene-block-poly-2-vinylpyridine (PS-b-P2VP) deposited as monolayer films onto surfaces show responsive behavior and are reversibly switchable between two states of different topography and surface chemistry. The as-coated films are in the form of arrays of nanoscale bumps, which can be transformed into arrays of nanoscale holes by switching through exposure to methanol. The use of these micellar films to act as switchable etch masks for the structu...

Intra-Subject Consistency and Reliability of Response Following 2 mA Transcranial Direct Current Stimulation.

Science.gov (United States)

Dyke, Katherine; Kim, Soyoung; Jackson, Georgina M; Jackson, Stephen R

Transcranial direct current stimulation (tDCS) is a popular non-invasive brain stimulation technique that has been shown to influence cortical excitability. While polarity specific effects have often been reported, this is not always the case, and variability in both the magnitude and direction of the effects have been observed. We aimed to explore the consistency and reliability of the effects of tDCS by investigating changes in cortical excitability across multiple testing sessions in the same individuals. A within subjects design was used to investigate the effects of anodal and cathodal tDCS applied to the motor cortex. Four experimental sessions were tested for each polarity in addition to two sham sessions. Transcranial magnetic stimulation (TMS) was used to measure cortical excitability (TMS recruitment curves). Changes in excitability were measured by comparing baseline measures and those taken immediately following 20 minutes of 2 mA stimulation or sham stimulation. Anodal tDCS significantly increased cortical excitability at a group level, whereas cathodal tDCS failed to have any significant effects. The sham condition also failed to show any significant changes. Analysis of intra-subject responses to anodal stimulation across four sessions suggest that the amount of change in excitability across sessions was only weakly associated, and was found to have poor reliability across sessions (ICC = 0.276). The effects of cathodal stimulation show even poorer reliability across sessions (ICC = 0.137). In contrast ICC analysis for the two sessions of sham stimulation reflect a moderate level of reliability (ICC = .424). Our findings indicate that although 2 mA anodal tDCS is effective at increasing cortical excitability at group level, the effects are unreliable across repeated testing sessions within individual participants. Our results suggest that 2 mA cathodal tDCS does not significantly alter cortical excitability immediately following

Intensity dependent effects of transcranial direct current stimulation on corticospinal excitability in chronic spinal cord injury.

Science.gov (United States)

Murray, Lynda M; Edwards, Dylan J; Ruffini, Giulio; Labar, Douglas; Stampas, Argyrios; Pascual-Leone, Alvaro; Cortes, Mar

2015-04-01

To investigate the effects of anodal transcranial direct current stimulation (a-tDCS) intensity on corticospinal excitability and affected muscle activation in individuals with chronic spinal cord injury (SCI). Single-blind, randomized, sham-controlled, crossover study. Medical research institute and rehabilitation hospital. Volunteers (N = 9) with chronic SCI and motor dysfunction in wrist extensor muscles. Three single session exposures to 20 minutes of a-tDCS (anode over the extensor carpi radialis [ECR] muscle representation on the left primary motor cortex, cathode over the right supraorbital area) using 1 mA, 2 mA, or sham stimulation, delivered at rest, with at least 1 week between sessions. Corticospinal excitability was assessed with motor-evoked potentials (MEPs) from the ECR muscle using surface electromyography after transcranial magnetic stimulation. Changes in spinal excitability, sensory threshold, and muscle strength were also investigated. Mean MEP amplitude significantly increased by approximately 40% immediately after 2mA a-tDCS (pre: 0.36 ± 0.1 mV; post: 0.47 ± 0.11 mV; P = .001), but not with 1 mA or sham. Maximal voluntary contraction measures remained unaltered across all conditions. Sensory threshold significantly decreased over time after 1mA (P = .002) and 2mA (P = .039) a-tDCS and did not change with sham. F-wave persistence showed a nonsignificant trend for increase (pre: 32% ± 12%; post: 41% ± 10%; follow-up: 46% ± 12%) after 2 mA stimulation. No adverse effects were reported with any of the experimental conditions. The a-tDCS can transiently raise corticospinal excitability to affected muscles in patients with chronic SCI after 2 mA stimulation. Sensory perception can improve with both 1 and 2 mA stimulation. This study gives support to the safe and effective use of a-tDCS using small electrodes in patients with SCI and highlights the importance of stimulation intensity. Copyright © 2015 American Congress of Rehabilitation

Is effect of transcranial direct current stimulation on visuomotor coordination dependent on task difficulty?

Directory of Open Access Journals (Sweden)

Yong Hyun Kwon

2015-01-01

Full Text Available Transcranial direct current stimulation (tDCS, an emerging technique for non-invasive brain stimulation, is increasingly used to induce changes in cortical excitability and modulate motor behavior, especially for upper limbs. The purpose of this study was to investigate the effects of tDCS of the primary motor cortex on visuomotor coordination based on three levels of task difficulty in healthy subjects. Thirty-eight healthy participants underwent real tDCS or sham tDCS. Using a single-blind, sham-controlled crossover design, tDCS was applied to the primary motor cortex. For real tDCS conditions, tDCS intensity was 1 mA while stimulation was applied for 15 minutes. For the sham tDCS, electrodes were placed in the same position, but the stimulator was turned off after 5 seconds. Visuomotor tracking task, consisting of three levels (levels 1, 2, 3 of difficulty with higher level indicating greater difficulty, was performed before and after tDCS application. At level 2, real tDCS of the primary motor cortex improved the accurate index compared to the sham tDCS. However, at levels 1 and 3, the accurate index was not significantly increased after real tDCS compared to the sham tDCS. These findings suggest that tasks of moderate difficulty may improve visuomotor coordination in healthy subjects when tDCS is applied compared with easier or more difficult tasks.

Switchable bio-inspired adhesives

Science.gov (United States)

Kroner, Elmar

2015-03-01

Geckos have astonishing climbing abilities. They can adhere to almost any surface and can run on walls and even stick to ceilings. The extraordinary adhesion performance is caused by a combination of a complex surface pattern on their toes and the biomechanics of its movement. These biological dry adhesives have been intensely investigated during recent years because of the unique combination of adhesive properties. They provide high adhesion, allow for easy detachment, can be removed residue-free, and have self-cleaning properties. Many aspects have been successfully mimicked, leading to artificial, bio-inspired, patterned dry adhesives, and were addressed and in some aspects they even outperform the adhesion capabilities of geckos. However, designing artificial patterned adhesion systems with switchable adhesion remains a big challenge; the gecko's adhesion system is based on a complex hierarchical surface structure and on advanced biomechanics, which are both difficult to mimic. In this paper, two approaches are presented to achieve switchable adhesion. The first approach is based on a patterned polydimethylsiloxane (PDMS) polymer, where adhesion can be switched on and off by applying a low and a high compressive preload. The switch in adhesion is caused by a reversible mechanical instability of the adhesive silicone structures. The second approach is based on a composite material consisting of a Nickel- Titanium (NiTi) shape memory alloy and a patterned adhesive PDMS layer. The NiTi alloy is trained to change its surface topography as a function of temperature, which results in a change of the contact area and of alignment of the adhesive pattern towards a substrate, leading to switchable adhesion. These examples show that the unique properties of bio-inspired adhesives can be greatly improved by new concepts such as mechanical instability or by the use of active materials which react to external stimuli.

High-definition transcranial direct current stimulation (HD-tDCS) of left dorsolateral prefrontal cortex affects performance in Balloon Analogue Risk Task (BART).

Science.gov (United States)

Guo, Heng; Zhang, Zhuoran; Da, Shu; Sheng, Xiaotian; Zhang, Xichao

2018-02-01

Studies on risk preferences have long been of great concern and have examined the neural basis underlying risk-based decision making. However, studies using conventional transcranial direct current stimulation (tDCS) revealed that bilateral stimulation could change risk propensity with limited evidence of precisely focalized unilateral high-definition transcranial direct current stimulation (HD-tDCS). The aim of this experiment was to investigate the effect of HD-tDCS focalizing the left dorsal lateral prefrontal cortex (DLPFC) on risk-taking behavior during the Balloon Analogue Risk Task (BART). This study was designed as a between-subject, single-blind, sham-controlled experiment. University students were randomly assigned to three groups: the anodal group (F3 anode, AF3, F1, F5, FC3 returned), the cathodal group (F3 cathodal, AF3, F1, F5, FC3 returned) and the sham group. Subsequently, 1.5-mA 20-min HD-tDCS was applied during the BART, and the Positive Affect and Negative Affect Scale (PANAS), the Sensation Seeking Scale-5 (SSS-5), and the Behavioral Inhibition System and Behavioral Approach System scale (BIS/BAS) were measured as control variables. The cathodal group earned less total money than the sham group, and no significant difference was observed between the anodal group and the sham group. These results showed that, to some extent, focalized unilateral cathodal HD-tDCS on left DLPFC could change performance during risky tasks and diminish risky decision making. Further studies are needed to investigate the dose effect and electrode distribution of HD-tDCS during risky tasks and examine synchronous brain activity to show the neural basis.

Transcranial vibro-acoustography can detect traumatic brain injury, in-vivo: Preliminary studies.

Science.gov (United States)

Suarez, Martin W; Dever, David D; Gu, Xiaohan; Ray Illian, P; McClintic, Abbi M; Mehic, Edin; Mourad, Pierre D

2015-08-01

Vibro-acoustography (VA) uses two or more beams of confocal ultrasound to generate local vibrations within their target tissue through induction of a time-dependent radiation force whose frequency equals that of the difference of the applied frequencies. While VA has proven effective for assaying the mechanical properties of clinically relevant tissue such as breast lesions and tissue calcifications, its application to brain remains unexplored. Here we investigate the ability of VA to detect acute and focal traumatic brain injury (TBI) in-vivo through the use of transcranially delivered high-frequency (2 MHz) diagnostic focused ultrasound to rat brain capable of generating measurable low-frequency (200-270 kHz) acoustic emissions from outside of the brain. We applied VA to acute sham-control and TBI model rats (sham N=6; TBI N=6) and observed that acoustic emissions, captured away from the site of TBI, had lower amplitudes for TBI as compared to sham-TBI animals. The sensitivity of VA to acute brain damage at frequencies currently transmittable across human skulls, as demonstrated in this preliminary study, supports the possibility that the VA methodology may one day serve as a technique for detecting TBI. Copyright © 2015. Published by Elsevier B.V.

Transcranial magnetic stimulation primes the effects of exercise therapy in multiple sclerosis.

Science.gov (United States)

Mori, Francesco; Ljoka, Concetta; Magni, Elisabetta; Codecà, Claudia; Kusayanagi, Hajime; Monteleone, Fabrizia; Sancesario, Andrea; Bernardi, Giorgio; Koch, Giacomo; Foti, Calogero; Centonze, Diego

2011-07-01

Exercise therapy (ET) can be beneficial in disabled multiple sclerosis (MS) patients. Intermittent transcranial magnetic theta burst stimulation (iTBS) induces long-term excitability changes of the cerebral cortex and may ameliorate spasticity in MS. We investigated whether the combination of iTBS and a program of ET can improve motor disability in MS patients. In a double-blind, sham-controlled trial, 30 participants were randomized to three different interventions: iTBS plus ET, sham stimulation plus ET, and iTBS alone. Before and after 2 weeks of treatment, measures of spasticity through the modified Ashworth scale (MAS) and the 88 items Multiple Sclerosis Spasticity Score questionnaire (MSSS-88), fatigue through the Fatigue Severity Scale (FSS), daily living activities (ADL) through the Barthel index and health-related quality of life (HRQoL) through the 54 items Multiple Sclerosis Quality of life inventory (MSQoL-54) were collected. iTBS plus ET reduced MAS, MSSS-88, FSS scores, while in the Barthel index and MSQoL-54, physical composite scores were increased. iTBS alone caused a reduction of the MAS score, while none of the measured scales showed significant changes after sham iTBS plus ET. iTBS associated with ET is a promising tool for motor rehabilitation of MS patients.

Oscillating Square Wave Transcranial Direct Current Stimulation (tDCS) Delivered During Slow Wave Sleep Does Not Improve Declarative Memory More Than Sham: A Randomized Sham Controlled Crossover Study.

Science.gov (United States)

Sahlem, Gregory L; Badran, Bashar W; Halford, Jonathan J; Williams, Nolan R; Korte, Jeffrey E; Leslie, Kimberly; Strachan, Martha; Breedlove, Jesse L; Runion, Jennifer; Bachman, David L; Uhde, Thomas W; Borckardt, Jeffery J; George, Mark S

2015-01-01

A 2006 trial in healthy medical students found that anodal slow oscillating tDCS delivered bi-frontally during slow wave sleep had an enhancing effect in declarative, but not procedural memory. Although there have been supporting animal studies, and similar findings in pathological groups, this study has not been replicated, or refuted, in the intervening years. We therefore tested these earlier results for replication using similar methods with the exception of current waveform (square in our study, nearly sinusoidal in the original). Our objective was to test the findings of a 2006 trial suggesting bi-frontal anodal tDCS during slow wave sleep enhances declarative memory. Twelve students (mean age 25, 9 women) free of medical problems underwent two testing conditions (active, sham) in a randomized counterbalanced fashion. Active stimulation consisted of oscillating square wave tDCS delivered during early Non-Rapid Eye Movement (NREM) sleep. The sham condition consisted of setting-up the tDCS device and electrodes, but not turning it on during sleep. tDCS was delivered bi-frontally with anodes placed at F3/F4, and cathodes placed at mastoids. Current density was 0.517 mA/cm(2), and oscillated between zero and maximal current at a frequency of 0.75 Hz. Stimulation occurred during five-five minute blocks with 1-min inter-block intervals (25 min total stimulation). The primary outcomes were both declarative memory consolidation measured by a paired word association test (PWA), and non-declarative memory, measured by a non-dominant finger-tapping test (FTT). We also recorded and analyzed sleep EEG. There was no difference in the number of paired word associations remembered before compared to after sleep [(active = 3.1 ± 3.0 SD more associations) (sham = 3.8 ± 3.1 SD more associations)]. Finger tapping improved, (non-significantly) following active stimulation [(3.6 ± 2.7 SD correctly typed sequences) compared to sham stimulation (2.3 ± 2.2 SD correctly typed

Pressure pain thresholds increase after preconditioning 1 Hz repetitive transcranial magnetic stimulation with transcranial direct current stimulation.

Science.gov (United States)

Moloney, Tonya M; Witney, Alice G

2014-01-01

The primary motor cortex (M1) is an effective target of non-invasive cortical stimulation (NICS) for pain threshold modulation. It has been suggested that the initial level of cortical excitability of M1 plays a key role in the plastic effects of NICS. Here we investigate whether transcranial direct current stimulation (tDCS) primed 1 Hz repetitive transcranial magnetic stimulation (rTMS) modulates experimental pressure pain thresholds and if this is related to observed alterations in cortical excitability. 15 healthy, male participants received 10 min 1 mA anodal, cathodal and sham tDCS to the left M1 before 15 min 1 Hz rTMS in separate sessions over a period of 3 weeks. Motor cortical excitability was recorded at baseline, post-tDCS priming and post-rTMS through recording motor evoked potentials (MEPs) from right FDI muscle. Pressure pain thresholds were determined by quantitative sensory testing (QST) through a computerized algometer, on the palmar thenar of the right hand pre- and post-stimulation. Cathodal tDCS-primed 1 Hz-rTMS was found to reverse the expected suppressive effect of 1 Hz rTMS on cortical excitability; leading to an overall increase in activity (ppain thresholds (ppain. This study demonstrates that priming the M1 before stimulation of 1 Hz-rTMS modulates experimental pressure pain thresholds in a safe and controlled manner, producing a form of analgesia.

Outcomes in spasticity after repetitive transcranial magnetic and transcranial direct current stimulations

OpenAIRE

Gunduz, Aysegul; Kumru, Hatice; Pascual-Leone, Alvaro

2014-01-01

Non-invasive brain stimulations mainly consist of repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Repetitive transcranial magnetic stimulation exhibits satisfactory outcomes in improving multiple sclerosis, stroke, spinal cord injury and cerebral palsy-induced spasticity. By contrast, transcranial direct current stimulation has only been studied in post-stroke spasticity. To better validate the efficacy of non-invasive brain stimulations in improving ...

Bi-frontal transcranial alternating current stimulation in the ripple range reduced overnight forgetting.

Science.gov (United States)

Ambrus, Géza Gergely; Pisoni, Alberto; Primaßin, Annika; Turi, Zsolt; Paulus, Walter; Antal, Andrea

2015-01-01

High frequency oscillations in the hippocampal structures recorded during sleep have been proved to be essential for long-term episodic memory consolidation in both animals and in humans. The aim of this study was to test if transcranial Alternating Current Stimulation (tACS) of the dorsolateral prefrontal cortex (DLPFC) in the hippocampal ripple range, applied bi-frontally during encoding, could modulate declarative memory performance, measured immediately after encoding, and after a night's sleep. An associative word-pair learning test was used. During an evening encoding phase, participants received 1 mA 140 Hz tACS or sham stimulation over both DLPFCs for 10 min while being presented twice with a list of word-pairs. Cued recall performance was investigated 10 min after training and the morning following the training session. Forgetting from evening to morning was observed in the sham condition, but not in the 140 Hz stimulation condition. 140 Hz tACS during encoding may have an effect on the consolidation of declarative material.

Effects of Prefrontal Transcranial Direct Current Stimulation and Motivation to Quit in Tobacco Smokers: A Randomized, Sham Controlled, Double-Blind Trial

Directory of Open Access Journals (Sweden)

Maria C. Vitor de Souza Brangioni

2018-01-01

Full Text Available Transcranial direct current stimulation (tDCS applied over the dorsolateral prefrontal cortex (DLPFC has been shown to reduce cravings in tobacco addiction; however, results have been somewhat mixed. In this study, we hypothesized that motivation to quit smoking is a critical factor of tDCS effects in smokers. Therefore, we conducted a double-blind, randomized clinical trial to evaluate the effects of both tDCS and motivation to quit on cigarette consumption and the relationship between these two factors. DLPFC tDCS was applied once a day for 5 days. Our primary outcome was the amount of cigarettes smoked per day. We collected this information at baseline (d1, at the end of the treatment period (d5, 2 days later (d7 and at the 4-week follow-up (d35. Visual Analog Scale (VAS for motivation to quit was collected at the same time-points. 36 subjects (45 ± 11 years old; 24.2 ± 11.5 cigarettes daily smoked, 21 women were randomized to receive either active or sham tDCS. In our multivariate analysis, as to take into account the mediation and moderation effects of motivation to quit, we found a significant main effect of tDCS, showing that tDCS was associated with a significant reduction of cigarettes smoked per day. We also showed a significant interaction effect of motivation to quit and treatment, supporting our hypothesis that tDCS effects were moderated by motivation to quit, indicating that higher levels of motivation were associated with a larger tDCS response. We found that the participants' motivation to quit alone, both at baseline and at follow-up, does not explain the decrease in the average cigarette consumption. Repetitive prefrontal tDCS coupled with high motivation significantly reduced cigarette consumption up to 4-weeks post-intervention.Clinical Trial Registration: http://ClinicalTrials.gov, NCT02146014.

Mechanics of responsive polymers via conformationally switchable molecules

Science.gov (United States)

Brighenti, Roberto; Artoni, Federico; Vernerey, Franck; Torelli, Martina; Pedrini, Alessandro; Domenichelli, Ilaria; Dalcanale, Enrico

2018-04-01

Active materials are those capable of giving some physical reaction under external stimuli coming from the environment such as temperature, pH, light, mechanical stress, etc. Reactive polymeric materials can be obtained through the introduction of switchable molecules in their network, i.e. molecules having two distinct stable conformations: if properly linked to the hosting polymer chains, the switching from one state to the other can promote a mechanical reaction of the material, detectable at the macroscale, and thus enables us to tune the response according to a desired functionality. In the present paper, the main aspects of the mechanical behavior of polymeric materials with embedded switchable molecules-properly linked to the polymer's chains-are presented and discussed. Starting from the micro mechanisms occurring in such active material, a continuum model is developed, providing a straightforward implementation in computational approaches. Finally, some experimental outcomes related to a switchable molecules (known as quinoxaline cavitands) added to an elastomeric PDMS under chemical stimuli, are presented and quantitatively discussed through the use of the developed mechanical framework.

Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Science.gov (United States)

Sehatzadeh, Shayan; Tu, Hong Anh; Palimaka, Stefan; Yap, Belinda; O'Reilly, Daria; Bowen, Jim; Higgins, Caroline; Holubowich, Corinne

2016-01-01

Background To date, several randomized controlled trials (RCTs) have shown the efficacy of repetitive transcranial magnetic stimulation (rTMS) in the treatment of major depression. Objective This analysis examined the antidepressant efficacy of rTMS in patients with treatment-resistant unipolar depression. Methods A literature search was performed for RCTs published from January 1, 1994, to November 20, 2014. The search was updated on March 1, 2015. Two independent reviewers evaluated the abstracts for inclusion, reviewed full texts of eligible studies, and abstracted data. Meta-analyses were conducted to obtain summary estimates. The primary outcome was changes in depression scores measured by the Hamilton Rating Scale for Depression (HRSD), and we considered, a priori, the mean difference of 3.5 points to be a clinically important treatment effect. Remission and response to the treatment were secondary outcomes, and we calculated number needed to treat on the basis of these outcomes. We examined the possibility of publication bias by constructing funnel plots and by Begg's and Egger's tests. A meta-regression was undertaken to examine the effect of specific rTMS technical parameters on the treatment effects. Results Twenty-three RCTs compared rTMS with sham, and six RCTs compared rTMS with electroconvulsive therapy (ECT). Trials of rTMS versus sham showed a statistically significant improvement in depression scores with rTMS (weighted mean difference [WMD] 2.31, 95% CI 1.19–3.43; P transcranial magnetic stimulation had a small short-term effect for improving depression in comparison with sham, but follow-up studies did not show that the small effect will continue for longer periods. PMID:27099642

Modulating Memory Performance in Healthy Subjects with Transcranial Direct Current Stimulation Over the Right Dorsolateral Prefrontal Cortex.

Science.gov (United States)

Smirni, Daniela; Turriziani, Patrizia; Mangano, Giuseppa Renata; Cipolotti, Lisa; Oliveri, Massimiliano

2015-01-01

The role of the Dorsolateral Prefrontal Cortex (DLPFC) in recognition memory has been well documented in lesion, neuroimaging and repetitive Transcranial Magnetic Stimulation (rTMS) studies. The aim of the present study was to investigate the effects of transcranial Direct Current Stimulation (tDCS) over the left and the right DLPFC during the delay interval of a non-verbal recognition memory task. 36 right-handed young healthy subjects participated in the study. The experimental task was an Italian version of Recognition Memory Test for unknown faces. Study included two experiments: in a first experiment, each subject underwent one session of sham tDCS and one session of left or right cathodal tDCS; in a second experiment each subject underwent one session of sham tDCS and one session of left or right anodal tDCS. Cathodal tDCS over the right DLPFC significantly improved non verbal recognition memory performance, while cathodal tDCS over the left DLPFC had no effect. Anodal tDCS of both the left and right DLPFC did not modify non verbal recognition memory performance. Complementing the majority of previous studies, reporting long term memory facilitations following left prefrontal anodal tDCS, the present findings show that cathodal tDCS of the right DLPFC can also improve recognition memory in healthy subjects.

Transcranial static magnetic field stimulation of the human motor cortex

Science.gov (United States)

Oliviero, Antonio; Mordillo-Mateos, Laura; Arias, Pablo; Panyavin, Ivan; Foffani, Guglielmo; Aguilar, Juan

2011-01-01

Abstract The aim of the present study was to investigate in healthy humans the possibility of a non-invasive modulation of motor cortex excitability by the application of static magnetic fields through the scalp. Static magnetic fields were obtained by using cylindrical NdFeB magnets. We performed four sets of experiments. In Experiment 1, we recorded motor potentials evoked by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex before and after 10 min of transcranial static magnetic field stimulation (tSMS) in conscious subjects. We observed an average reduction of motor cortex excitability of up to 25%, as revealed by TMS, which lasted for several minutes after the end of tSMS, and was dose dependent (intensity of the magnetic field) but not polarity dependent. In Experiment 2, we confirmed the reduction of motor cortex excitability induced by tSMS using a double-blind sham-controlled design. In Experiment 3, we investigated the duration of tSMS that was necessary to modulate motor cortex excitability. We found that 10 min of tSMS (compared to 1 min and 5 min) were necessary to induce significant effects. In Experiment 4, we used transcranial electric stimulation (TES) to establish that the tSMS-induced reduction of motor cortex excitability was not due to corticospinal axon and/or spinal excitability, but specifically involved intracortical networks. These results suggest that tSMS using small static magnets may be a promising tool to modulate cerebral excitability in a non-invasive, painless, and reversible way. PMID:21807616

Block copolymer micelles as switchable templates for nanofabrication.

Science.gov (United States)

Krishnamoorthy, Sivashankar; Pugin, Raphaël; Brugger, Juergen; Heinzelmann, Harry; Hoogerwerf, Arno C; Hinderling, Christian

2006-04-11

Block copolymer inverse micelles from polystyrene-block-poly-2-vinylpyridine (PS-b-P2VP) deposited as monolayer films onto surfaces show responsive behavior and are reversibly switchable between two states of different topography and surface chemistry. The as-coated films are in the form of arrays of nanoscale bumps, which can be transformed into arrays of nanoscale holes by switching through exposure to methanol. The use of these micellar films to act as switchable etch masks for the structuring of the underlying material to form either pillars or holes depending on the switching state is demonstrated.

Transcranial magnetic stimulation of right inferior parietal cortex causally influences prefrontal activation for visual detection

DEFF Research Database (Denmark)

Leitao, Joana; Thielscher, Axel; Lee, Hweeling

2017-01-01

-parietal areas integrating the evidence into a decision variable that is compared to a decisional threshold. This concurrent transcranial magnetic stimulation (TMS)-fMRI study applied 10 Hz bursts of four TMS (or Sham) pulses to the intraparietal sulcus (IPS) to investigate the causal influence of IPS...... affect participants' performance accuracy, it affected how observers adjusted their response times after making an error. We therefore suggest that activation increases in superior frontal gyri for misses relative to correct responses may not be critical for signal detection performance, but rather...

Transcranial Stimulation of the Dorsolateral Prefrontal Cortex Prevents Stress-Induced Working Memory Deficits.

Science.gov (United States)

Bogdanov, Mario; Schwabe, Lars

2016-01-27

Stress is known to impair working memory performance. This disruptive effect of stress on working memory has been linked to a decrease in the activity of the dorsolateral prefrontal cortex (dlPFC). In the present experiment, we tested whether transcranial direct current stimulation (tDCS) of the dlPFC can prevent stress-induced working memory impairments. We tested 120 healthy participants in a 2 d, sham-controlled, double-blind between-subjects design. Participants completed a test of their individual baseline working memory capacity on day 1. On day 2, participants were exposed to either a stressor or a control manipulation before they performed a visuospatial and a verbal working memory task. While participants completed the tasks, anodal, cathodal, or sham tDCS was applied over the right dlPFC. Stress impaired working memory performance in both tasks, albeit to a lesser extent in the verbal compared with the visuospatial working memory task. This stress-induced working memory impairment was prevented by anodal, but not sham or cathodal, stimulation of the dlPFC. Compared with sham or cathodal stimulation, anodal tDCS led to significantly better working memory performance in both tasks after stress. Our findings indicate a causal role of the dlPFC in working memory impairments after acute stress and point to anodal tDCS as a promising tool to reduce cognitive deficits related to working memory in stress-related mental disorders, such as depression, schizophrenia, or post-traumatic stress disorder. Working memory deficits are prominent in stress-related mental disorders, such as depression, schizophrenia, or post-traumatic stress disorder. Similar working memory impairments have been observed in healthy individuals exposed to acute stress. So far, attempts to prevent such stress-induced working memory deficits focused mainly on pharmacological interventions. Here, we tested the idea that transcranial direct current stimulation of the dorsolateral prefrontal

Enhanced motor learning following task-concurrent dual transcranial direct current stimulation.

Directory of Open Access Journals (Sweden)

Sophia Karok

Full Text Available OBJECTIVE: Transcranial direct current stimulation (tDCS of the primary motor cortex (M1 has beneficial effects on motor performance and motor learning in healthy subjects and is emerging as a promising tool for motor neurorehabilitation. Applying tDCS concurrently with a motor task has recently been found to be more effective than applying stimulation before the motor task. This study extends this finding to examine whether such task-concurrent stimulation further enhances motor learning on a dual M1 montage. METHOD: Twenty healthy, right-handed subjects received anodal tDCS to the right M1, dual tDCS (anodal current over right M1 and cathodal over left M1 and sham tDCS in a repeated-measures design. Stimulation was applied for 10 mins at 1.5 mA during an explicit motor learning task. Response times (RT and accuracy were measured at baseline, during, directly after and 15 mins after stimulation. Motor cortical excitability was recorded from both hemispheres before and after stimulation using single-pulse transcranial magnetic stimulation. RESULTS: Task-concurrent stimulation with a dual M1 montage significantly reduced RTs by 23% as early as with the onset of stimulation (p<0.01 with this effect increasing to 30% at the final measurement. Polarity-specific changes in cortical excitability were observed with MEPs significantly reduced by 12% in the left M1 and increased by 69% in the right M1. CONCLUSION: Performance improvement occurred earliest in the dual M1 condition with a stable and lasting effect. Unilateral anodal stimulation resulted only in trendwise improvement when compared to sham. Therefore, task-concurrent dual M1 stimulation is most suited for obtaining the desired neuromodulatory effects of tDCS in explicit motor learning.

Low intensity transcranial electric stimulation

DEFF Research Database (Denmark)

Antal, Andrea; Alekseichuk, I; Bikson, M

2017-01-01

Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears...

Effects of Bilateral Repetitive Transcranial Magnetic Stimulation on Post-Stroke Dysphagia.

Science.gov (United States)

Park, Eunhee; Kim, Min Su; Chang, Won Hyuk; Oh, Su Mi; Kim, Yun Kwan; Lee, Ahee; Kim, Yun-Hee

Optimal protocol of repetitive transcranial magnetic stimulation (rTMS) on post-stroke dysphagia remains uncertain with regard to its clinical efficacy. The aim of the present study is to investigate the effects of high-frequency rTMS at the bilateral motor cortices over the cortical representation of the mylohyoid muscles in the patients with post-stroke dysphagia. This study was a single-blind, randomized controlled study with a blinded observer. Thirty-five stroke patients were randomly divided into three intervention groups: the bilateral stimulation group, the unilateral stimulation group, and the sham stimulation group. For the bilateral stimulation group, 500 pulses of 10 Hz rTMS over the ipsilesional and 500 pulses of 10 Hz rTMS over the contralesional motor cortices over the cortical areas that project to the mylohyoid muscles were administered daily for 2 consecutive weeks. For the unilateral stimulation group, 500 pulses of 10 Hz rTMS over the ipsilesional motor cortex over the cortical representation of the mylohyoid muscle and the same amount of sham rTMS over the contralesional hemisphere were applied. For the sham stimulation group, sham rTMS was applied at the bilateral motor cortices. Clinical swallowing function and videofluoroscopic swallowing studies were assessed before the intervention (T0), immediately after the intervention (T1) and 3 weeks after the intervention (T2) using Clinical Dysphagia Scale (CDS), Dysphagia Outcome and Severity Scale (DOSS), Penetration Aspiration Scale (PAS), and Videofluoroscopic Dysphagia Scale (VDS). There were significant time and intervention interaction effects in the CDS, DOSS, PAS, and VDS scores (p dysphagia therapies. Copyright © 2016. Published by Elsevier Inc.

Monitoring transcranial direct current stimulation induced changes in cortical excitability during the serial reaction time task.

Science.gov (United States)

Ambrus, Géza Gergely; Chaieb, Leila; Stilling, Roman; Rothkegel, Holger; Antal, Andrea; Paulus, Walter

2016-03-11

The measurement of the motor evoked potential (MEP) amplitudes using single pulse transcranial magnetic stimulation (TMS) is a common method to observe changes in motor cortical excitability. The level of cortical excitability has been shown to change during motor learning. Conversely, motor learning can be improved by using anodal transcranial direct current stimulation (tDCS). In the present study, we aimed to monitor cortical excitability changes during an implicit motor learning paradigm, a version of the serial reaction time task (SRTT). Responses from the first dorsal interosseous (FDI) and forearm flexor (FLEX) muscles were recorded before, during and after the performance of the SRTT. Online measurements were combined with anodal, cathodal or sham tDCS for the duration of the SRTT. Negative correlations between the amplitude of online FDI MEPs and SRTT reaction times (RTs) were observed across the learning blocks in the cathodal condition (higher average MEP amplitudes associated with lower RTs) but no significant differences in the anodal and sham conditions. tDCS did not have an impact on SRTT performance, as would be predicted based on previous studies. The offline before-after SRTT MEP amplitudes showed an increase after anodal and a tendency to decrease after cathodal stimulation, but these changes were not significant. The combination of different interventions during tDCS might result in reduced efficacy of the stimulation that in future studies need further attention. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Small Square Reconfigurable Antenna with Switchable Single/Tri-Band Functions

Directory of Open Access Journals (Sweden)

M. Borhani Kakhki

2016-04-01

Full Text Available A novel frequency reconfigurable slot antenna for suitable switchable radiations at WLAN and a tri-band at Bluetooth, WiMAX and upper WLAN applications is designed and fabricated. Switchable frequency responses are achieved by implementation of a PIN diode within the antenna ground plane. The antenna structure is consist of a square radiation patch with an E-shaped slot, a modified ground plane with an inverted T-shaped strip that act as a parasitic stub and two parallel slots and a protruded strip which is connected to the parasitic stub with a PIN diode. The presented antenna has a compact size of 20×20 mm2 while providing switchable radiations at 2.36-2.5 GHz Bluetooth, 3.51-3.79 GHz WiMAX, and 5.47-5.98 GHz WLAN when diode is ON and 5.04-6.13 GHz WLAN when diode is OFF.

No Change in Social Decision-Making Following Transcranial Direct Current Stimulation of the Right Temporoparietal Junction

Directory of Open Access Journals (Sweden)

Laura F. Blair-West

2018-04-01

Full Text Available The right temporoparietal junction (rTPJ is thought to play an important role in social cognition and pro-social decision-making. One way to explore this link is through the use of transcranial direct current stimulation (tDCS, a non-invasive brain stimulation method that is able to modulate cortical activity. The aim of this research was therefore to determine whether anodal tDCS to the rTPJ altered response to a social decision-making task. In this study, 34 healthy volunteers participated in a single-center, double-blinded, sham-controlled crossover design. Subjects received 20 min of active/sham anodal tDCS to the rTPJ before undertaking the Ultimatum Game (UG, a neuroeconomics paradigm in which participants are forced to choose between monetary reward and punishing an opponent's unfairness. Contrary to expectations, we found no significant difference between anodal and sham stimulation with regard to either the total number or reaction time of unfair offer rejections in the UG. This study draws attention to methodological issues in tDCS studies of the rTPJ, and highlights the complexity of social decision-making in the UG.

No Change in Social Decision-Making Following Transcranial Direct Current Stimulation of the Right Temporoparietal Junction.

Science.gov (United States)

Blair-West, Laura F; Hoy, Kate E; Hall, Phillip J; Fitzgerald, Paul B; Fitzgibbon, Bernadette M

2018-01-01

The right temporoparietal junction (rTPJ) is thought to play an important role in social cognition and pro-social decision-making. One way to explore this link is through the use of transcranial direct current stimulation (tDCS), a non-invasive brain stimulation method that is able to modulate cortical activity. The aim of this research was therefore to determine whether anodal tDCS to the rTPJ altered response to a social decision-making task. In this study, 34 healthy volunteers participated in a single-center, double-blinded, sham-controlled crossover design. Subjects received 20 min of active/sham anodal tDCS to the rTPJ before undertaking the Ultimatum Game (UG), a neuroeconomics paradigm in which participants are forced to choose between monetary reward and punishing an opponent's unfairness. Contrary to expectations, we found no significant difference between anodal and sham stimulation with regard to either the total number or reaction time of unfair offer rejections in the UG. This study draws attention to methodological issues in tDCS studies of the rTPJ, and highlights the complexity of social decision-making in the UG.

Neuroplastic effects of transcranial direct current stimulation on painful symptoms reduction in chronic Hepatitis C: a phase II randomized, double blind, sham controlled trial

Directory of Open Access Journals (Sweden)

Aline Patricia Brietzke

2016-01-01

Full Text Available Introduction: Pegylated Interferon Alpha (Peg-IFN in combination with other drugs is the standard treatment for chronic hepatitis C infection (HCV and is related to severe painful symptoms. The aim of this study was access the efficacy of transcranial direct current stimulation (tDCS in controlling the painful symptoms related to Peg-IFN side effects. Material and Methods: In this phase II double-blind trial, twenty eight (n=28 HCV subjects were randomized to receive either five consecutive days of active tDCS (n=14 or sham (n=14 during five consecutive days with anodal stimulation over the primary motor cortex region using 2 mA for 20 minutes. The primary outcomes were visual analogue scale (VAS pain and brain-derived neurotrophic factor (BDNF serum levels. Secondary outcomes were the pressure-pain threshold (PPT, the Brazilian Profile of Chronic Pain: Screen (B-PCP:S and drug analgesics use. Results: tDCS reduced the VAS scores (P<0.003, with a mean pain drop of 56% (p<0.001. Furthermore, tDCS was able to enhance BDNF levels (p<0.01. The mean increase was 37.48% in the active group. Finally, tDCS raised PPT (p<0.001 and reduced the B-PCP:S scores and analgesic use (p<0.05. Conclusions: Five sessions of tDCS were effective in reducing the painful symptoms in HCV patients undergoing Peg-IFN treatment. These findings support the efficacy of tDCS as a promising therapeutic tool to improve the tolerance of the side effects related to the use of Peg-IFN. Future larger studies (phase III and IV trials are needed to confirm the clinical use of the therapeutic effects of tDCS in such condition. Trial registration: Brazilian Human Health Regulator for Research with the approval number CAAE 07802012.0.0000.5327

Are Participants Aware of the Type and Intensity of Transcranial Direct Current Stimulation?

Directory of Open Access Journals (Sweden)

Matthew F Tang

Full Text Available Transcranial direct current stimulation (tDCS is commonly used to alter cortical excitability but no experimental study has yet determined whether human participants are able to distinguish between the different types (anodal, cathodal, and sham of stimulation. If they can then they are not blind to experimental conditions. We determined whether participants could identify different types of stimulation (anodal, cathodal, and sham and current strengths after experiencing the sensations of stimulation during current onset and offset (which are associated with the most intense sensations in Experiment 1 and also with a prolonged period of stimulation in Experiment 2. We first familiarized participants with anodal, cathodal, and sham stimulation at both 1 and 2 mA over either primary motor or visual cortex while their sensitivity to small changes in visual stimuli was assessed. The different stimulation types were then applied for a short (Experiment 1 or extended (Experiment 2 period with participants indicating the type and strength of the stimulation on the basis of the evoked sensations. Participants were able to identify the intensity of stimulation with shorter, but not longer periods, of stimulation at better than chance levels but identification of the different stimulation types was at chance levels. This result suggests that even after exposing participants to stimulation, and ensuring they are fully aware of the existence of a sham condition, they are unable to identify the type of stimulation from transient changes in stimulation intensity or from more prolonged stimulation. Thus participants are able to identify intensity of stimulation but not the type of stimulation.

Anodal transcranial direct current stimulation of right temporoparietal area inhibits self-recognition.

Science.gov (United States)

Payne, Sophie; Tsakiris, Manos

2017-02-01

Self-other discrimination is a crucial mechanism for social cognition. Neuroimaging and neurostimulation research has pointed to the involvement of the right temporoparietal region in a variety of self-other discrimination tasks. Although repetitive transcranial magnetic stimulation over the right temporoparietal area has been shown to disrupt self-other discrimination in face-recognition tasks, no research has investigated the effect of increasing the cortical excitability in this region on self-other face discrimination. Here we used transcranial direct current stimulation (tDCS) to investigate changes in self-other discrimination with a video-morphing task in which the participant's face morphed into, or out of, a familiar other's face. The task was performed before and after 20 min of tDCS targeting the right temporoparietal area (anodal, cathodal, or sham stimulation). Differences in task performance following stimulation were taken to indicate a change in self-other discrimination. Following anodal stimulation only, we observed a significant increase in the amount of self-face needed to distinguish between self and other. The findings are discussed in relation to the control of self and other representations and to domain-general theories of social cognition.

Boosting the LTP-like plasticity effect of intermittent theta-burst stimulation using gamma transcranial alternating current stimulation.

Science.gov (United States)

Guerra, Andrea; Suppa, Antonio; Bologna, Matteo; D'Onofrio, Valentina; Bianchini, Edoardo; Brown, Peter; Di Lazzaro, Vincenzo; Berardelli, Alfredo

2018-03-24

Transcranial Alternating Current Stimulation (tACS) consists in delivering electric current to the brain using an oscillatory pattern that may entrain the rhythmic activity of cortical neurons. When delivered at gamma frequency, tACS modulates motor performance and GABA-A-ergic interneuron activity. Since interneuronal discharges play a crucial role in brain plasticity phenomena, here we co-stimulated the primary motor cortex (M1) in healthy subjects by means of tACS during intermittent theta-burst stimulation (iTBS), a transcranial magnetic stimulation paradigm known to induce long-term potentiation (LTP)-like plasticity. We measured and compared motor evoked potentials before and after gamma, beta and sham tACS-iTBS. While we delivered gamma-tACS, we also measured short-interval intracortical inhibition (SICI) to detect any changes in GABA-A-ergic neurotransmission. Gamma, but not beta and sham tACS, significantly boosted and prolonged the iTBS-induced after-effects. Interestingly, the extent of the gamma tACS-iTBS after-effects correlated directly with SICI changes. Overall, our findings point to a link between gamma oscillations, interneuronal GABA-A-ergic activity and LTP-like plasticity in the human M1. Gamma tACS-iTBS co-stimulation might represent a new strategy to enhance and prolong responses to plasticity-inducing protocols, thereby lending itself to future applications in the neurorehabilitation setting. Copyright © 2018 Elsevier Inc. All rights reserved.

Combined transcranial direct current stimulation and home-based occupational therapy for upper limb motor impairment following intracerebral hemorrhage

DEFF Research Database (Denmark)

Mortensen, Jesper; Figlewski, Krystian; Andersen, Henning

2016-01-01

PURPOSE: To investigate the combined effect of transcranial direct current stimulation (tDCS) and home-based occupational therapy on activities of daily living (ADL) and grip strength, in patients with upper limb motor impairment following intracerebral hemorrhage (ICH). METHODS: A double......-blind randomized controlled trial with one-week follow-up. Patients received five consecutive days of occupational therapy at home, combined with either anodal (n = 8) or sham (n = 7) tDCS. The primary outcome was ADL performance, which was assessed with the Jebsen-Taylor test (JTT). RESULTS: Both groups improved...... with the sham group, from baseline to post-assessment (p = 0.158). CONCLUSIONS: Five consecutive days of tDCS combined with occupational therapy provided greater improvements in grip strength compared with occupational therapy alone. tDCS is a promising add-on intervention regarding training of upper limb motor...

Improved reading measures in adults with dyslexia following transcranial direct current stimulation treatment.

Science.gov (United States)

Heth, Inbahl; Lavidor, Michal

2015-04-01

To better understand the contribution of the dorsal system to word reading, we explored transcranial direct current stimulation (tDCS) effects when adults with developmental dyslexia received active stimulation over the visual extrastriate area MT/V5, which is dominated by magnocellular input. Stimulation was administered in 5 sessions spread over two weeks, and reading speed and accuracy as well as reading fluency were assessed before, immediately after, and a week after the end of the treatment. A control group of adults with developmental dyslexia matched for age, gender, reading level, vocabulary and block-design WAIS-III sub-tests and reading level was exposed to the same protocol but with sham stimulation. The results revealed that active, but not sham stimulation, significantly improved reading speed and fluency. This finding suggests that the dorsal stream may play a role in efficient retrieval from the orthographic input lexicon in the lexical route. It also underscores the potential of tDCS as an intervention tool for improving reading speed, at least in adults with developmental dyslexia. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bi-frontal transcranial alternating current stimulation in the ripple range reduced overnight forgetting

Directory of Open Access Journals (Sweden)

Géza Gergely eAmbrus

2015-09-01

Full Text Available High frequency oscillations in the hippocampal structures recorded during sleep have been proved to be essential for long-term episodic memory consolidation in both animals and in humans. The aim of this study was to test if transcranial Alternating Current Stimulation (tACS of the dorsolateral prefrontal cortex (DLPFC in the hippocampal ripple range, applied bi-frontally during encoding, could modulate declarative memory performance, measured immediately after encoding, and after a night’s sleep. An associative word-pair learning test, taken from Marshall and colleagues, was used. During an evening encoding phase, participants received 1 mA 140 Hz tACS or sham stimulation over both DLPFCs for 10 minutes while being presented twice with a list of word-pairs. Cued recall performance was investigated 10 minutes after training and the morning following the training session. Forgetting from evening to morning was observed in the sham condition, but not in the 140 Hz stimulation condition. 140 Hz tACS during encoding may have an effect on the consolidation of declarative material.

Transcranial direct current stimulation versus caffeine as a fatigue countermeasure.

Science.gov (United States)

McIntire, Lindsey K; McKinley, R Andy; Nelson, Justin M; Goodyear, Chuck

To assess the efficacy of using transcranial direct current stimulation (tDCS) to remediate the deleterious effects of fatigue induced by sleep deprivation and compare these results to caffeine, a commonly used fatigue countermeasure. Based on previous research, tDCS of the dorsolateral prefrontal cortex (DLPFC) can modulate attention and arousal. The authors hypothesize that tDCS can be an effective fatigue countermeasure. Five groups of ten participants each received either active tDCS and placebo gum at 1800, caffeine gum with sham tDCS at 1800, active tDCS and placebo gum at 0400, caffeine gum with sham tDCS at 0400, or sham tDCS with placebo gum at 1800 and 0400 during 36-h of sustained wakefulness. Participants completed a vigilance task, working memory task, psychomotor vigilance task (PVT), and a procedural game beginning at 1800 h and continued every two hours throughout the night until 1900 the next day. tDCS dosed at 1800 provided 6 h of improved attentional accuracy and reaction times compared to the control group. Caffeine did not produce an effect. Both tDCS groups also had an improved effect on mood. Participants receiving tDCS reported feeling more vigor, less fatigue, and less bored throughout the night compared to the control and caffeine groups. We believe tDCS could be a powerful fatigue countermeasure. The effects appear to be comparable or possibly more beneficial than caffeine because they are longer lasting and mood remains more positive. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of repetitive transcranial magnetic stimulation on rectal function and emotion in humans

International Nuclear Information System (INIS)

Aizawa, Yuuichi; Morishita, Joe; Kano, Michiko; Mori, Takayuki; Izumi, Shin-ichi; Kanazawa, Motoyori; Fukudo, Shin; Tsutsui, Kenichiro; Iijima, Toshio

2011-01-01

A previous brain imaging study demonstrated activation of the right dorsolateral prefrontal cortex (DLPFC) during visceral nociception, and this activation was associated with anxiety. We hypothesized that functional modulation of the right DLPFC by repetitive transcranial magnetic stimulation (rTMS) can reveal the actual role of right DLPFC in brain-gut interactions in humans. Subjects were 11 healthy males aged 23.5±1.4 (mean±spin echo (SE)) years. Viscerosensory evoked potential (VEP) with sham (0 mA) or actual (30 mA) electrical stimulation (ES) of the rectum was taken after sham, low frequency rTMS at 0.1 Hz, and high frequency rTMS at 10 Hz to the right DLPFC. Rectal tone was measured with a rectal barostat. Visceral perception and emotion were analyzed using an ordinate scale, rectal barostat, and VEP. Low frequency rTMS significantly reduced anxiety evoked by ES at 30 mA (p<0.05). High frequency rTMS-30 mA ES significantly produced more phasic volume events than sham rTMS-30 mA ES (p<0.05). We successfully modulated the gastrointestinal function of healthy individuals through rTMS to the right DLPFC. Thus, rTMS to the DLPFC appears to modulate the affective, but not direct, component of visceral perception and motility of the rectum. (author)

Transcranial direct current stimulation over the primary motor vs prefrontal cortex in refractory chronic migraine: A pilot randomized controlled trial.

Science.gov (United States)

Andrade, Suellen Marinho; de Brito Aranha, Renata Emanuela Lyra; de Oliveira, Eliane Araújo; de Mendonça, Camila Teresa Ponce Leon; Martins, Wanessa Kallyne Nascimento; Alves, Nelson Torro; Fernández-Calvo, Bernardino

2017-07-15

Although transcranial direct current stimulation (tDCS) represents a therapeutic option for the prophylaxis of chronic migraine, the target area for application of the electrical current to the cortex has not yet been well established. Here we sought to determine whether a treatment protocol involving 12 sessions of 2mA, 20min anodal stimulation of the left primary motor (M1) or dorsolateral prefrontal cortex (DLPFC) could offer clinical benefits in the management of pain from migraine. Thirteen participants were assessed before and after treatment, using the Headache Impact Test-6, Visual Analogue Scale and Medical Outcomes Study 36 - Item Short - Form Health Survey. After treatment, group DLPFC exhibited a better performance compared with groups M1 and sham. On intragroup comparison, groups DLPFC and M1 exhibited a greater reduction in headache impact and pain intensity and a higher quality of life after treatment. No significant change was found in group sham. The participants in group M1 exhibited more adverse effects, especially headache, heartburn, and sleepiness, than did those in the other two groups. Transcranial direct current stimulation is a safe and efficacious technique for treating chronic migraine. However, it should be kept in mind that the site of cortical stimulation might modulate the patient's response to treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Using non-invasive transcranial stimulation to improve motor and cognitive function in Parkinson's disease: a systematic review and meta-analysis.

Science.gov (United States)

Goodwill, Alicia M; Lum, Jarrad A G; Hendy, Ashlee M; Muthalib, Makii; Johnson, Liam; Albein-Urios, Natalia; Teo, Wei-Peng

2017-11-01

Parkinson's disease (PD) is a neurodegenerative disorder affecting motor and cognitive abilities. There is no cure for PD, therefore identifying safe therapies to alleviate symptoms remains a priority. This meta-analysis quantified the effectiveness of repetitive transcranial magnetic stimulation (rTMS) and transcranial electrical stimulation (TES) to improve motor and cognitive dysfunction in PD. PubMed, EMBASE, Web of Science, Google Scholar, Scopus, Library of Congress and Cochrane library were searched. 24 rTMS and 9 TES studies (n = 33) with a sham control group were included for analyses. The Physiotherapy Evidence Database and Cochrane Risk of Bias showed high quality (7.5/10) and low bias with included studies respectively. Our results showed an overall positive effect in favour of rTMS (SMD = 0.394, CI [0.106-0.683], p = 0.007) and TES (SMD = 0.611, CI [0.188-1.035], p = 0.005) compared with sham stimulation on motor function, with no significant differences detected between rTMS and TES (Q [1] = 0.69, p = 0.406). Neither rTMS nor TES improved cognition. No effects for stimulation parameters on motor or cognitive function were observed. To enhance the clinical utility of non-invasive brain stimulation (NBS), individual prescription of stimulation parameters based upon symptomology and resting excitability state should be a priority of future research.

Pressure pain thresholds increase after preconditioning 1 Hz repetitive transcranial magnetic stimulation with transcranial direct current stimulation.

Directory of Open Access Journals (Sweden)

Tonya M Moloney

Full Text Available BACKGROUND: The primary motor cortex (M1 is an effective target of non-invasive cortical stimulation (NICS for pain threshold modulation. It has been suggested that the initial level of cortical excitability of M1 plays a key role in the plastic effects of NICS. OBJECTIVE: Here we investigate whether transcranial direct current stimulation (tDCS primed 1 Hz repetitive transcranial magnetic stimulation (rTMS modulates experimental pressure pain thresholds and if this is related to observed alterations in cortical excitability. METHOD: 15 healthy, male participants received 10 min 1 mA anodal, cathodal and sham tDCS to the left M1 before 15 min 1 Hz rTMS in separate sessions over a period of 3 weeks. Motor cortical excitability was recorded at baseline, post-tDCS priming and post-rTMS through recording motor evoked potentials (MEPs from right FDI muscle. Pressure pain thresholds were determined by quantitative sensory testing (QST through a computerized algometer, on the palmar thenar of the right hand pre- and post-stimulation. RESULTS: Cathodal tDCS-primed 1 Hz-rTMS was found to reverse the expected suppressive effect of 1 Hz rTMS on cortical excitability; leading to an overall increase in activity (p<0.001 with a parallel increase in pressure pain thresholds (p<0.01. In contrast, anodal tDCS-primed 1 Hz-rTMS resulted in a corresponding decrease in cortical excitability (p<0.05, with no significant effect on pressure pain. CONCLUSION: This study demonstrates that priming the M1 before stimulation of 1 Hz-rTMS modulates experimental pressure pain thresholds in a safe and controlled manner, producing a form of analgesia.

Extended Remediation of Sleep Deprived-Induced Working Memory Deficits Using fMRI-guided Transcranial Magnetic Stimulation

Science.gov (United States)

Luber, Bruce; Steffener, Jason; Tucker, Adrienne; Habeck, Christian; Peterchev, Angel V.; Deng, Zhi-De; Basner, Robert C.; Stern, Yaakov; Lisanby, Sarah H.

2013-01-01

Study Objectives: We attempted to prevent the development of working memory (WM) impairments caused by sleep deprivation using fMRI-guided repetitive transcranial magnetic stimulation (rTMS). Novel aspects of our fMRI-guided rTMS paradigm included the use of sophisticated covariance methods to identify functional networks in imaging data, and the use of fMRI-targeted rTMS concurrent with task performance to modulate plasticity effects over a longer term. Design: Between-groups mixed model. Setting: TMS, MRI, and sleep laboratory study. Participants: 27 subjects (13 receiving Active rTMS, and 14 Sham) completed the sleep deprivation protocol, with another 21 (10 Active, 11 Sham) non-sleep deprived subjects run in a second experiment. Interventions: Our previous covariance analysis had identified a network, including occipital cortex, which demonstrated individual differences in resilience to the deleterious effects of sleep deprivation on WM performance. Five Hz rTMS was applied to left lateral occipital cortex while subjects performed a WM task during 4 sessions over the course of 2 days of total sleep deprivation. Measurements and Results: At the end of the sleep deprivation period, Sham sleep deprived subjects exhibited degraded performance in the WM task. In contrast, those receiving Active rTMS did not show the slowing and lapsing typical in sleep deprivation, and instead performed similarly to non- sleep deprived subjects. Importantly, the Active sleep deprivation group showed rTMS-induced facilitation of WM performance a full 18 hours after the last rTMS session. Conclusions: Over the course of sleep deprivation, these results indicate that rTMS applied concurrently with WM task performance affected neural circuitry involved in WM to prevent its full impact. Citation: Luber B; Steffener J; Tucker A; Habeck C; Peterchev AV; Deng ZD; Basner RC; Stern Y; Lisanby SH. Extended remediation of sleep deprived-induced working memory deficits using f

Safer Battery with Switchable Polymer Coating, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to utilize a switchable polymer (SWP) to prevent catastrophic failure due to internal shorting or overdischarge in lithium-ion...

The facilitative effect of transcranial direct current stimulation on visuospatial working memory in patients with diabetic polyneuropathy: a pre-post sham-controlled study

Directory of Open Access Journals (Sweden)

YI-JEN WU

2016-09-01

Full Text Available Diabetes mellitus (DM can lead to diabetic polyneuropathy (DPN and cognitive deficits that manifest as peripheral and central neuropathy, respectively. In this study we investigated the relationship between visuospatial working memory (VSWM capacity and DPN severity, and attempted to improve VSWM in DPN patients via the use of transcranial direct current stimulation (tDCS. Sixteen DPN patients and sixteen age- and education-matched healthy control subjects received Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV and Montreal Cognitive Assessment (MOCA for baseline cognitive assessment. A forward- and backward-recall computerized Corsi block tapping task (CBT, both with and without a concurrent motor interference task was used to measure VSWM capacity. Each DPN patient underwent a pre-treatment CBT, followed by tDCS or sham treatment, then a post-treatment CBT on two separate days. We found that although patients with severe DPN (Dyck’s grade 2a or 2b showed comparable general intelligence scores on WAIS-IV as their age- and education-matched healthy counterparts, they nonetheless showed mild cognitive impairment on MOCA and working memory deficit on digit-span test of WAIS-IV. Furthermore, patients’ peripheral nerve conduction velocity (NCV was positively correlated with their VSWM span in the most difficult CBT condition that involved backward-recall with motor interference such that patients with worse NCV also had lower VSWM span. Most importantly, anodal tDCS over the right DLPFC was able to improve low-performing patients’ VSWM span to be on par with the high-performers, thereby eliminating the correlation between NCV and VSWM. In summary, these findings suggest that 1 mild cognitive impairment and severe peripheral neuropathy can coexist with unequal severity in diabetic patients, 2 the positive correlation of VSWM and NCV suggests a link between peripheral and central neuropathies and 3 anodal tDCS over the right DLPFC can

Thermally switchable dielectrics

Science.gov (United States)

Dirk, Shawn M.; Johnson, Ross S.

2013-04-30

Precursor polymers to conjugated polymers, such as poly(phenylene vinylene), poly(poly(thiophene vinylene), poly(aniline vinylene), and poly(pyrrole vinylene), can be used as thermally switchable capacitor dielectrics that fail at a specific temperature due to the non-conjugated precursor polymer irreversibly switching from an insulator to the conjugated polymer, which serves as a bleed resistor. The precursor polymer is a good dielectric until it reaches a specific temperature determined by the stability of the leaving groups. Conjugation of the polymer backbone at high temperature effectively disables the capacitor, providing a `built-in` safety mechanism for electronic devices.

Transcranial magnetic stimulation of the brain: guidelines for pain treatment research.

Science.gov (United States)

Klein, Max M; Treister, Roi; Raij, Tommi; Pascual-Leone, Alvaro; Park, Lawrence; Nurmikko, Turo; Lenz, Fred; Lefaucheur, Jean-Pascal; Lang, Magdalena; Hallett, Mark; Fox, Michael; Cudkowicz, Merit; Costello, Ann; Carr, Daniel B; Ayache, Samar S; Oaklander, Anne Louise

2015-09-01

Recognizing that electrically stimulating the motor cortex could relieve chronic pain sparked development of noninvasive technologies. In transcranial magnetic stimulation (TMS), electromagnetic coils held against the scalp influence underlying cortical firing. Multiday repetitive transcranial magnetic stimulation (rTMS) can induce long-lasting, potentially therapeutic brain plasticity. Nearby ferromagnetic or electronic implants are contraindications. Adverse effects are minimal, primarily headaches. Single provoked seizures are very rare. Transcranial magnetic stimulation devices are marketed for depression and migraine in the United States and for various indications elsewhere. Although multiple studies report that high-frequency rTMS of the motor cortex reduces neuropathic pain, their quality has been insufficient to support Food and Drug Administration application. Harvard's Radcliffe Institute therefore sponsored a workshop to solicit advice from experts in TMS, pain research, and clinical trials. They recommended that researchers standardize and document all TMS parameters and improve strategies for sham and double blinding. Subjects should have common well-characterized pain conditions amenable to motor cortex rTMS and studies should be adequately powered. They recommended standardized assessment tools (eg, NIH's PROMIS) plus validated condition-specific instruments and consensus-recommended metrics (eg, IMMPACT). Outcomes should include pain intensity and qualities, patient and clinician impression of change, and proportions achieving 30% and 50% pain relief. Secondary outcomes could include function, mood, sleep, and/or quality of life. Minimum required elements include sample sources, sizes, and demographics, recruitment methods, inclusion and exclusion criteria, baseline and posttreatment means and SD, adverse effects, safety concerns, discontinuations, and medication-usage records. Outcomes should be monitored for at least 3 months after initiation

Effects of transcranial direct current stimulation (tDCS) on binge eating disorder.

Science.gov (United States)

Burgess, Emilee E; Sylvester, Maria D; Morse, Kathryn E; Amthor, Frank R; Mrug, Sylvie; Lokken, Kristine L; Osborn, Mary K; Soleymani, Taraneh; Boggiano, Mary M

2016-10-01

To investigate the effect of transcranial direct current stimulation (tDCS) on food craving, intake, binge eating desire, and binge eating frequency in individuals with binge eating disorder (BED). N = 30 adults with BED or subthreshold BED received a 20-min 2 milliampere (mA) session of tDCS targeting the dorsolateral prefrontal cortex (DLPFC; anode right/cathode left) and a sham session. Food image ratings assessed food craving, a laboratory eating test assessed food intake, and an electronic diary recorded binge variables. tDCS versus sham decreased craving for sweets, savory proteins, and an all-foods category, with strongest reductions in men (p tDCS also decreased total and preferred food intake by 11 and 17.5%, regardless of sex (p tDCS administration (p tDCS in BED. Stimulation of the right DLPFC suggests that enhanced cognitive control and/or decreased need for reward may be possible functional mechanisms. The results support investigation of repeated tDCS as a safe and noninvasive treatment adjunct for BED. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2016; 49:930-936). © 2016 Wiley Periodicals, Inc.

Reduction of chronic abdominal pain in patients with inflammatory bowel disease through transcranial direct current stimulation: a randomized controlled trial.

Science.gov (United States)

Volz, Magdalena S; Farmer, Annabelle; Siegmund, Britta

2016-02-01

Inflammatory bowel disease (IBD) is frequently associated with chronic abdominal pain (CAP). Transcranial direct current stimulation (tDCS) has been proven to reduce chronic pain. This study aimed to investigate the effects of tDCS in patients with CAP due to IBD. This randomized, sham-controlled, double blind, parallel-designed study included 20 patients with either Crohn disease or ulcerative colitis with CAP (≥3/10 on the visual analog scale (VAS) in 3/6 months). Anodal or sham tDCS was applied over the primary motor cortex for 5 consecutive days (2 mA, 20 minutes). Assessments included VAS, pressure pain threshold, inflammatory markers, and questionnaires on quality of life, functional and disease specific symptoms (Irritable Bowel Syndrome-Severity Scoring System [IBS-SSS]), disease activity, and pain catastrophizing. Follow-up data were collected 1 week after the end of the stimulation. Statistical analyses were performed using analysis of variance and t tests. There was a significant reduction of abdominal pain in the anodal tDCS group compared with sham tDCS. This effect was evident in changes in VAS and pressure pain threshold on the left and right sides of the abdomen. In addition, 1 week after stimulation, pain reduction remained significantly decreased in the right side of the abdomen. There was also a significant reduction in scores on pain catastrophizing and on IBS-SSS when comparing both groups. Inflammatory markers and disease activity did not differ significantly between groups throughout the experiment. Transcranial direct current stimulation proved to be an effective and clinically relevant therapeutic strategy for CAP in IBD. The analgesic effects observed are unrelated to inflammation and disease activity, which emphasizes central pain mechanisms in CAP.

Optically switchable photonic metasurfaces

Energy Technology Data Exchange (ETDEWEB)

Waters, R. F.; MacDonald, K. F. [Centre for Photonic Metamaterials and Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom); Hobson, P. A. [QinetiQ Ltd., Cody Technology Park, Farnborough, Hampshire GU14 0LX (United Kingdom); Zheludev, N. I. [Centre for Photonic Metamaterials and Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom); Centre for Disruptive Photonic Technologies and The Photonics Institute, Nanyang Technological University, Singapore 637371 (Singapore)

2015-08-24

We experimentally demonstrate an optically switchable gallium-based metasurface, in which a reversible light-induced transition between solid and liquid phases occurring in a confined nanoscale surface layer of the metal drives significant changes in reflectivity and absorption. The metasurface architecture resonantly enhances the metal's “active plasmonic” phase-change nonlinearity by an order of magnitude, offering high contrast all-optical switching in the near-infrared range at low, μW μm{sup −2}, excitation intensities.

HMSIW-based switchable units using super compact loaded shunt stubs and its applications on SIW/HMSIW switches

Science.gov (United States)

Chen, Haidong; Che, Wenquan; Zhang, Tianyu; Cao, Yue; Feng, Wenjie

2018-06-01

Half-mode substrate integrated waveguide (HMSIW) switchable unit, built by HMSIW section with loaded single or multi-microstrip shunt stub(s), was proposed in this work. Both shorted and opened stubs were studied, investigated and compared, bandwidth enhancement method for proposed switchable units was proposed and demonstrated. Based on these switchable units, narrowband and broadband HMSIW single-pole-single-through (SPST) switches, SIW SPST switch and SIW/HMSIW-based single-pole-double-through (SPDT) switch were designed, fabricated and measured. Good performances were observed experimentally for these proposed circuits, showing the advantages of proposed concept and an excellent candidate for switchable or reconfigurable SIW/HMSIW circuits or systems.

Passband switchable microwave photonic multiband filter

Science.gov (United States)

Ge, Jia; Fok, Mable P.

2015-01-01

A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity. PMID:26521693

Optimal control and performance of photovoltachromic switchable glazing for building integration in temperate climates

International Nuclear Information System (INIS)

Favoino, Fabio; Fiorito, Francesco; Cannavale, Alessandro; Ranzi, Gianluca; Overend, Mauro

2016-01-01

Highlights: • The features and properties of photovoltachromic switchable glazing are presented. • The different possible control strategies for the switchable glazing are presented. • Thermal and daylight performance are co-simulated for rule-based and optimal control. • A novel building performance simulation framework is developed for this aim. • Switchable glazing performance is compared for different controls and climates. - Abstract: The development of adaptive building envelope technologies, and particularly of switchable glazing, can make significant contributions to decarbonisation targets. It is therefore essential to quantify their effect on building energy use and indoor environmental quality when integrated into buildings. The evaluation of their performance presents new challenges when compared to conventional “static” building envelope systems, as they require design and control aspects to be evaluated together, which are also mutually interrelated across thermal and visual physical domains. This paper addresses these challenges by presenting a novel simulation framework for the performance evaluation of responsive building envelope technologies and, particularly, of switchable glazing. This is achieved by integrating a building energy simulation tool and a lighting simulation one, in a control optimisation framework to simulate advanced control of adaptive building envelopes. The performance of a photovoltachromic glazing is evaluated according to building energy use, Useful Daylight Illuminance, glare risk and load profile matching indicators for a sun oriented office building in different temperate climates. The original architecture of photovoltachromic cell provides an automatic control of its transparency as a function of incoming solar irradiance. However, to fully explore the building integration potential of photovoltachromic technology, different control strategies are evaluated, from passive and simple rule based controls, to

Frontal transcranial direct current stimulation (tDCS) abolishes list-method directed forgetting.

Science.gov (United States)

Silas, Jonathan; Brandt, Karen R

2016-03-11

It is a point of controversy as to whether directed forgetting effects are a result of active inhibition or a change of context initiated by the instruction to forget. In this study we test the causal role of active inhibition in directed forgetting. By applying cathodal transcranial direct current stimulation (tDCS) over the right prefrontal cortex we suppressed cortical activity commonly associated with inhibitory control. Participants who underwent real brain stimulation before completing the directed forgetting paradigm showed no directed forgetting effects. Conversely, those who underwent sham brain stimulation demonstrated classical directed forgetting effects. We argue that these findings suggest that inhibition is the primary mechanism that results in directed forgetting costs and benefits. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Transcranial Alternating Current Stimulation (tACS Mechanisms and Protocols

Directory of Open Access Journals (Sweden)

Amir V. Tavakoli

2017-09-01

Full Text Available Perception, cognition and consciousness can be modulated as a function of oscillating neural activity, while ongoing neuronal dynamics are influenced by synaptic activity and membrane potential. Consequently, transcranial alternating current stimulation (tACS may be used for neurological intervention. The advantageous features of tACS include the biphasic and sinusoidal tACS currents, the ability to entrain large neuronal populations, and subtle control over somatic effects. Through neuromodulation of phasic, neural activity, tACS is a powerful tool to investigate the neural correlates of cognition. The rapid development in this area requires clarity about best practices. Here we briefly introduce tACS and review the most compelling findings in the literature to provide a starting point for using tACS. We suggest that tACS protocols be based on functional brain mechanisms and appropriate control experiments, including active sham and condition blinding.

No Effect of Cathodal Transcranial Direct Current Stimulation on Fear Memory in Healthy Human Subjects

Directory of Open Access Journals (Sweden)

Aditya Mungee

2016-11-01

Full Text Available Background: Studies have demonstrated that fear memories can be modified using non-invasive methods. Recently, we demonstrated that anodal transcranial direct current stimulation (tDCS of the right dorsolateral prefrontal cortex is capable of enhancing fear memories. Here, we examined the effects of cathodal tDCS of the right dorsolateral prefrontal cortex during fear reconsolidation in humans. Methods: Seventeen young, healthy subjects were randomly assigned to two groups, which underwent fear conditioning with mild electric stimuli paired with a visual stimulus. Twenty-four hours later, both groups were shown a reminder of the conditioned fearful stimulus. Shortly thereafter, they received either tDCS (right prefrontal—cathodal, left supraorbital—anodal for 20 min at 1 mA, or sham stimulation. A day later, fear responses of both groups were compared. Results: On Day 3, during fear response assessment, there were no significant differences between the tDCS and sham group (p > 0.05. Conclusion: We conclude that cathodal tDCS of the right dorsolateral prefrontal cortex (right prefrontal—cathodal, left supraorbital—anodal did not influence fear memories.

Anodal Transcranial Direct Current Stimulation Promotes Frontal Compensatory Mechanisms in Healthy Elderly Subjects.

Science.gov (United States)

Cespón, Jesús; Rodella, Claudia; Rossini, Paolo M; Miniussi, Carlo; Pellicciari, Maria C

2017-01-01

Recent studies have demonstrated that transcranial direct current stimulation (tDCS) is potentially useful to improve working memory. In the present study, young and elderly subjects performed a working memory task ( n -back task) during an electroencephalogram recording before and after receiving anodal, cathodal, and sham tDCS over the left dorsolateral prefrontal cortex (DLPFC). We investigated modulations of behavioral performance and electrophysiological correlates of working memory processes (frontal and parietal P300 event-related potentials). A strong tendency to modulated working memory performance was observed after the application of tDCS. In detail, young, but not elderly, subjects benefited from additional practice in the absence of real tDCS, as indicated by their more accurate responses after sham tDCS. The cathodal tDCS had no effect in any group of participants. Importantly, anodal tDCS improved accuracy in elderly. Moreover, increased accuracy after anodal tDCS was correlated with a larger frontal P300 amplitude. These findings suggest that, in elderly subjects, improved working memory after anodal tDCS applied over the left DLPFC may be related to the promotion of frontal compensatory mechanisms, which are related to attentional processes.

Anodal Transcranial Direct Current Stimulation Promotes Frontal Compensatory Mechanisms in Healthy Elderly Subjects

Directory of Open Access Journals (Sweden)

Jesús Cespón

2017-12-01

Full Text Available Recent studies have demonstrated that transcranial direct current stimulation (tDCS is potentially useful to improve working memory. In the present study, young and elderly subjects performed a working memory task (n-back task during an electroencephalogram recording before and after receiving anodal, cathodal, and sham tDCS over the left dorsolateral prefrontal cortex (DLPFC. We investigated modulations of behavioral performance and electrophysiological correlates of working memory processes (frontal and parietal P300 event-related potentials. A strong tendency to modulated working memory performance was observed after the application of tDCS. In detail, young, but not elderly, subjects benefited from additional practice in the absence of real tDCS, as indicated by their more accurate responses after sham tDCS. The cathodal tDCS had no effect in any group of participants. Importantly, anodal tDCS improved accuracy in elderly. Moreover, increased accuracy after anodal tDCS was correlated with a larger frontal P300 amplitude. These findings suggest that, in elderly subjects, improved working memory after anodal tDCS applied over the left DLPFC may be related to the promotion of frontal compensatory mechanisms, which are related to attentional processes.

Chronic treatment with repetitive transcranial magnetic stimulation inhibits seizure induction by electroconvulsive shock in rats.

Science.gov (United States)

Fleischmann, A; Hirschmann, S; Dolberg, O T; Dannon, P N; Grunhaus, L

1999-03-15

Studies in laboratory animals suggest that repetitive transcranial magnetic stimulation (rTMS) and electroconvulsive shock (ECS) increase seizure inhibition acutely. This study was designed to explore whether chronic rTMS would also have seizure inhibition properties. To this purpose we administered rTMS (Magstim Rapid) and sham rTMS twice daily (2.5 T, 4-sec train duration, 20 Hz) to two groups of 10 rats for 16 days. The rTMS coil was a 50-mm figure-8 coil held directly over the rat's head. Raters were blind to experimental groups. On days 11, 17, and 21 (5 days after the last rTMS) ECS was administered with a Siemens convulsator using three electrical charge levels. Variables examined were the presence or absence of seizures and seizure length (measured from the initiation of the tonic contraction until the end of the limb movement). At day 11 rTMS had no effect on seizures, and both rTMS and sham rTMS animals convulsed equally. At day 17, however, rTMS-treated animals convulsed significantly less (both at presence/absence of seizures, and at seizure length) than sham rTMS animals. At day 21 the effects of rTMS had disappeared. These findings suggest that rTMS administered chronically leads to changes in seizure threshold similar to those reported for ECS and ECT; however, these effects were short-lived.

The impact of cerebellar transcranial direct current stimulation (tDCS) on learning fine-motor sequences.

Science.gov (United States)

Shimizu, Renee E; Wu, Allan D; Samra, Jasmine K; Knowlton, Barbara J

2017-01-05

The cerebellum has been shown to be important for skill learning, including the learning of motor sequences. We investigated whether cerebellar transcranial direct current stimulation (tDCS) would enhance learning of fine motor sequences. Because the ability to generalize or transfer to novel task variations or circumstances is a crucial goal of real world training, we also examined the effect of tDCS on performance of novel sequences after training. In Study 1, participants received either anodal, cathodal or sham stimulation while simultaneously practising three eight-element key press sequences in a non-repeating, interleaved order. Immediately after sequence practice with concurrent tDCS, a transfer session was given in which participants practised three interleaved novel sequences. No stimulation was given during transfer. An inhibitory effect of cathodal tDCS was found during practice, such that the rate of learning was slowed in comparison to the anodal and sham groups. In Study 2, participants received anodal or sham stimulation and a 24 h delay was added between the practice and transfer sessions to reduce mental fatigue. Although this consolidation period benefitted subsequent transfer for both tDCS groups, anodal tDCS enhanced transfer performance. Together, these studies demonstrate polarity-specific effects on fine motor sequence learning and generalization.This article is part of the themed issue 'New frontiers for statistical learning in the cognitive sciences'. © 2016 The Author(s).

Long-term effects of repetitive transcranial magnetic stimulation (rTMS) in patients with chronic tinnitus.

Science.gov (United States)

Kleinjung, Tobias; Eichhammer, Peter; Langguth, Berthold; Jacob, Peter; Marienhagen, Joerg; Hajak, Goeran; Wolf, Stephan R; Strutz, Juergen

2005-04-01

The pathophysiologic mechanisms of idiopathic tinnitus remain unclear. Recent studies demonstrated focal brain activation in the auditory cortex of patients with chronic tinnitus. Low-frequency repetitive transcranial magnetic stimulation (rTMS) is able to reduce cortical hyperexcitability. Fusing of the individual PET-scan with the structural MRI-scan (T1, MPRAGE) allowed us to identify exactly the area of increased metabolic activity in the auditory cortex of patients with chronic tinnitus. With the use of a neuronavigational system, this target area was exactly stimulated by the figure 8-shaped magnetic coil. In a prospective study, rTMS (110% motor threshold; 1 Hz; 2000 stimuli/day over 5 days) was performed using a placebo controlled cross-over design. Patients were blinded regarding the stimulus condition. For the sham stimulation a specific sham-coil system was used. Fourteen patients were followed for 6 months. Treatment outcome was assessed with a specific tinnitus questionnaire (Goebel and Hiller). Tertiary referral medical center. Increased metabolic activation in the auditory cortex was verified in all patients. After 5 days of verum rTMS, a highly significant improvement of the tinnitus score was found whereas the sham treatment did not show any significant changes. The treatment outcome after 6 months still demonstrated significant reduction of tinnitus score. These preliminary results demonstrate that neuronavigated rTMS offers new possibilities in the understanding and treatment of chronic tinnitus.

Transcranial Random Noise Stimulation-induced plasticity is NMDA-receptor independent but sodium-channel blocker and benzodiazepines sensitive

Directory of Open Access Journals (Sweden)

Leila eChaieb

2015-04-01

Full Text Available Background: Application of transcranial random noise stimulation (tRNS between 0.1 and 640 Hz of the primary motor cortex (M1 for 10 minutes induces a persistent excitability increase lasting for at least 60 minutes. However, the mechanism of tRNS-induced cortical excitability alterations is not yet fully understood. Objective: The main aim of this study was to get first efficacy data with regard to the possible neuronal effect of tRNS. Methods: Single-pulse transcranial magnetic stimulation (TMS was used to measure levels of cortical excitability before and after combined application of tRNS at an intensity of 1mA for 10mins stimulation duration and a pharmacological agent (or sham on 8 healthy male participants. Results: The sodium channel blocker carbamazepine showed a tendency towards inhibiting MEPs 5-60 mins poststimulation. The GABAA agonist lorazepam suppressed tRNS-induced cortical excitability increases at 0-20 and 60 min time points. The partial NMDA receptor agonist D-cycloserine, the NMDA receptor antagonist dextromethorphan and the D2/D3 receptor agonist ropinirole had no significant effects on the excitability increases seen with tRNS.Conclusions: In contrast to transcranial direct current stimulation (tDCS, aftereffects of tRNS are seem to be not NMDA receptor dependent and can be suppressed by benzodiazepines suggesting that tDCS and tRNS depend upon different mechanisms.

Developing and validating a sham cupping device.

Science.gov (United States)

Lee, Myeong Soo; Kim, Jong-In; Kong, Jae Cheol; Lee, Dong-Hyo; Shin, Byung-Cheul

2010-12-01

The aims of this study were to develop a sham cupping device and to validate its use as a placebo control for healthy volunteers. A sham cupping device was developed by establishing a small hole to reduce the negative pressure after suction such that inner pressure could not be maintained in the cup. We enrolled 34 healthy participants to evaluate the validity of the sham cupping device as a placebo control. The participants were informed that they would receive either real or sham cupping and were asked which treatment they thought they had received. Other sensations and adverse events related to cupping therapy were investigated. 17 patients received real cupping therapy and 17 received sham cupping. The two groups felt similar sensations. There was a tendency for subjects to feel that real cupping created a stronger sensation than sham cupping (48.9±21.4 vs 33.3±20.3 on a 100mm visual analogue scale). There were only mild to moderate adverse events observed in both groups. We developed a new sham cupping device that seems to provide a credible control for real cupping therapy by producing little or no negative pressure. This conclusion was supported by a pilot study, but more rigorous research is warranted regarding the use of this device.

Transcranial magnetic stimulation of the brain: guidelines for pain treatment research

Science.gov (United States)

Klein, Max M.; Treister, Roi; Raij, Tommi; Pascual-Leone, Alvaro; Park, Lawrence; Nurmikko, Turo; Lenz, Fred; Lefaucheur, Jean-Pascal; Lang, Magdalena; Hallett, Mark; Fox, Michael; Cudkowicz, Merit; Costello, Ann; Carr, Daniel B.; Ayache, Samar S.; Oaklander, Anne Louise

2015-01-01

Abstract Recognizing that electrically stimulating the motor cortex could relieve chronic pain sparked development of noninvasive technologies. In transcranial magnetic stimulation (TMS), electromagnetic coils held against the scalp influence underlying cortical firing. Multiday repetitive transcranial magnetic stimulation (rTMS) can induce long-lasting, potentially therapeutic brain plasticity. Nearby ferromagnetic or electronic implants are contraindications. Adverse effects are minimal, primarily headaches. Single provoked seizures are very rare. Transcranial magnetic stimulation devices are marketed for depression and migraine in the United States and for various indications elsewhere. Although multiple studies report that high-frequency rTMS of the motor cortex reduces neuropathic pain, their quality has been insufficient to support Food and Drug Administration application. Harvard's Radcliffe Institute therefore sponsored a workshop to solicit advice from experts in TMS, pain research, and clinical trials. They recommended that researchers standardize and document all TMS parameters and improve strategies for sham and double blinding. Subjects should have common well-characterized pain conditions amenable to motor cortex rTMS and studies should be adequately powered. They recommended standardized assessment tools (eg, NIH's PROMIS) plus validated condition-specific instruments and consensus-recommended metrics (eg, IMMPACT). Outcomes should include pain intensity and qualities, patient and clinician impression of change, and proportions achieving 30% and 50% pain relief. Secondary outcomes could include function, mood, sleep, and/or quality of life. Minimum required elements include sample sources, sizes, and demographics, recruitment methods, inclusion and exclusion criteria, baseline and posttreatment means and SD, adverse effects, safety concerns, discontinuations, and medication-usage records. Outcomes should be monitored for at least 3 months after

Transcranial direct current stimulation improves word retrieval in healthy and nonfluent aphasic subjects.

Science.gov (United States)

Fiori, Valentina; Coccia, Michela; Marinelli, Chiara V; Vecchi, Veronica; Bonifazi, Silvia; Ceravolo, M Gabriella; Provinciali, Leandro; Tomaiuolo, Francesco; Marangolo, Paola

2011-09-01

A number of studies have shown that modulating cortical activity by means of transcranial direct current stimulation (tDCS) affects performances of both healthy and brain-damaged subjects. In this study, we investigated the potential of tDCS to enhance associative verbal learning in 10 healthy individuals and to improve word retrieval deficits in three patients with stroke-induced aphasia. In healthy individuals, tDCS (20 min, 1 mA) was applied over Wernicke's area (position CP5 of the International 10-20 EEG System) while they learned 20 new "words" (legal nonwords arbitrarily assigned to 20 different pictures). The healthy subjects participated in a randomized counterbalanced double-blind procedure in which they were subjected to one session of anodic tDCS over left Wernicke's area, one sham session over this location and one session of anodic tDCS stimulating the right occipito-parietal area. Each experimental session was performed during a different week (over three consecutive weeks) with 6 days of intersession interval. Over 2 weeks, three aphasic subjects participated in a randomized double-blind experiment involving intensive language training for their anomic difficulties in two tDCS conditions. Each subject participated in five consecutive daily sessions of anodic tDCS (20 min, 1 mA) and sham stimulation over Wernicke's area while they performed a picture-naming task. By the end of each week, anodic tDCS had significantly improved their accuracy on the picture-naming task. Both normal subjects and aphasic patients also had shorter naming latencies during anodic tDCS than during sham condition. At two follow-ups (1 and 3 weeks after the end of treatment), performed only in two aphasic subjects, response accuracy and reaction times were still significantly better in the anodic than in the sham condition, suggesting a long-term effect on recovery of their anomic disturbances.

Response variability of different anodal transcranial direct current stimulation intensities across multiple sessions.

Science.gov (United States)

Ammann, Claudia; Lindquist, Martin A; Celnik, Pablo A

It is well known that transcranial direct current stimulation (tDCS) is capable of modulating corticomotor excitability. However, a source of growing concern has been the observed inter- and intra-individual variability of tDCS-responses. Recent studies have assessed whether individuals respond in a predictable manner across repeated sessions of anodal tDCS (atDCS). The findings of these investigations have been inconsistent, and their methods have some limitations (i.e. lack of sham condition or testing only one tDCS intensity). To study inter- and intra-individual variability of atDCS effects at two different intensities on primary motor cortex (M1) excitability. Twelve subjects participated in a crossover study testing 7-min atDCS over M1 in three separate conditions (2 mA, 1 mA, sham) each repeated three times separated by 48 h. Motor evoked potentials were recorded before and after stimulation (up to 30min). Time of testing was maintained consistent within participants. To estimate the reliability of tDCS effects across sessions, we calculated the Intra-class Correlation Coefficient (ICC). AtDCS at 2 mA, but not 1 mA, significantly increased cortical excitability at the group level in all sessions. The overall ICC revealed fair to high reliability of tDCS effects for multiple sessions. Given that the distribution of responses showed important variability in the sham condition, we established a Sham Variability-Based Threshold to classify responses and to track individual changes across sessions. Using this threshold an intra-individual consistent response pattern was then observed only for the 2 mA condition. 2 mA anodal tDCS results in consistent intra- and inter-individual increases of M1 excitability. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of an NMDA antagonist on the auditory mismatch negativity response to transcranial direct current stimulation.

Science.gov (United States)

Impey, Danielle; de la Salle, Sara; Baddeley, Ashley; Knott, Verner

2017-05-01

Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation which uses a weak constant current to alter cortical excitability and activity temporarily. tDCS-induced increases in neuronal excitability and performance improvements have been observed following anodal stimulation of brain regions associated with visual and motor functions, but relatively little research has been conducted with respect to auditory processing. Recently, pilot study results indicate that anodal tDCS can increase auditory deviance detection, whereas cathodal tDCS decreases auditory processing, as measured by a brain-based event-related potential (ERP), mismatch negativity (MMN). As evidence has shown that tDCS lasting effects may be dependent on N-methyl-D-aspartate (NMDA) receptor activity, the current study investigated the use of dextromethorphan (DMO), an NMDA antagonist, to assess possible modulation of tDCS's effects on both MMN and working memory performance. The study, conducted in 12 healthy volunteers, involved four laboratory test sessions within a randomised, placebo and sham-controlled crossover design that compared pre- and post-anodal tDCS over the auditory cortex (2 mA for 20 minutes to excite cortical activity temporarily and locally) and sham stimulation (i.e. device is turned off) during both DMO (50 mL) and placebo administration. Anodal tDCS increased MMN amplitudes with placebo administration. Significant increases were not seen with sham stimulation or with anodal stimulation during DMO administration. With sham stimulation (i.e. no stimulation), DMO decreased MMN amplitudes. Findings from this study contribute to the understanding of underlying neurobiological mechanisms mediating tDCS sensory and memory improvements.

On/off-switchable anti-neoplastic nanoarchitecture

Science.gov (United States)

Patra, Hirak K.; Imani, Roghayeh; Jangamreddy, Jaganmohan R.; Pazoki, Meysam; Iglič, Aleš; Turner, Anthony P. F.; Tiwari, Ashutosh

2015-09-01

Throughout the world, there are increasing demands for alternate approaches to advanced cancer therapeutics. Numerous potentially chemotherapeutic compounds are developed every year for clinical trial and some of them are considered as potential drug candidates. Nanotechnology-based approaches have accelerated the discovery process, but the key challenge still remains to develop therapeutically viable and physiologically safe materials suitable for cancer therapy. Here, we report a high turnover, on/off-switchable functionally popping reactive oxygen species (ROS) generator using a smart mesoporous titanium dioxide popcorn (TiO2 Pops) nanoarchitecture. The resulting TiO2 Pops, unlike TiO2 nanoparticles (TiO2 NPs), are exceptionally biocompatible with normal cells. Under identical conditions, TiO2 Pops show very high photocatalytic activity compared to TiO2 NPs. Upon on/off-switchable photo activation, the TiO2 Pops can trigger the generation of high-turnover flash ROS and can deliver their potential anticancer effect by enhancing the intracellular ROS level until it crosses the threshold to open the ‘death gate’, thus reducing the survival of cancer cells by at least six times in comparison with TiO2 NPs without affecting the normal cells.

Motor cortex tRNS improves pain, affective and cognitive impairment in patients with fibromyalgia: preliminary results of a randomised sham-controlled trial.

Science.gov (United States)

Curatolo, Massimiliano; La Bianca, Giuseppe; Cosentino, Giuseppe; Baschi, Roberta; Salemi, Giuseppe; Talotta, Rossella; Romano, Marcello; Triolo, Giovanni; De Tommaso, Marina; Fierro, Brigida; Brighina, Filippo

2017-01-01

Fibromyalgia (FM) is a clinical syndrome characterised by widespread musculoskeletal pain, chronic fatigue, cognitive deficits, and sleep and mood disorders. The effectiveness of most pharmacological treatments is limited, and there is a need for new, effective and well-tolerated therapies. It has recently been shown that transcranial direct-current stimulation (tDCS) of the motor cortex reduces pain, and that tDCS of the dorso-lateral prefrontal cortex (DLPFC) improves anxiety, depression and cognitive impairment in FM patients. The new technique of transcranial random noise stimulation (tRNS) using randomly changing alternating currents has very recently been shown to improve working memory and pain in limited series of patients with FM or neuropathic pain. The aim of this study was to investigate the clinical effects of primary motor cortex (M1) tRNS in FM patients. Twenty female FM patients aged 26-67 years were randomised to undergo active (real) or placebo (sham) tRNS sessions on five days a week (Monday-Friday) for two weeks. Each patient was evaluated before and after treatment using a visual analogue scale (VAS), the Fibromyalgia Impact Questionnaire (FIQ), the Hospital Anxiety and Depression Scale (HADS), the Trail Making Test (TMT), the Rey Auditory Verbal Learning Test (RAVLT), the Forward and Backward Digit Span test, and the FAS verbal fluency test. In comparison with sham treatment, active tRNS of M1 induced a general improvement in the clinical picture of FM, with a significant reduction in pain, depression, anxiety and FIQ scores and a significant improvement in TMT (A), RAVLT and FAS scores. These findings suggest that tRNS of M1 can be very effective in relieving FM symptoms. Unlike motor cortex tDCS, it seems to counteract both pain and cognitive disturbances, possibly because the invoked mechanism of stochastic resonance synchronises neural firing and thus leads to more widespread and lasting effects.

Cerebellar transcranial direct current stimulation improves adaptive postural control.

Science.gov (United States)

Poortvliet, Peter; Hsieh, Billie; Cresswell, Andrew; Au, Jacky; Meinzer, Marcus

2018-01-01

Rehabilitation interventions contribute to recovery of impaired postural control, but it remains a priority to optimize their effectiveness. A promising strategy may involve transcranial direct current stimulation (tDCS) of brain areas involved in fine-tuning of motor adaptation. This study explored the effects of cerebellar tDCS (ctDCS) on postural recovery from disturbance by Achilles tendon vibration. Twenty-eight healthy volunteers participated in this sham-ctDCS controlled study. Standing blindfolded on a force platform, four trials were completed: 60 s quiet standing followed by 20 min active (anodal-tDCS, 1 mA, 20 min, N = 14) or sham-ctDCS (40 s, N = 14) tDCS; three quiet standing trials with 15 s of Achilles tendon vibration and 25 s of postural recovery. Postural steadiness was quantified as displacement, standard deviation and path derived from the center of pressure (COP). Baseline demographics and quiet standing postural steadiness, and backwards displacement during vibration were comparable between groups. However, active-tDCS significantly improved postural steadiness during vibration and reduced forward displacement and variability in COP derivatives during recovery. We demonstrate that ctDCS results in short-term improvement of postural adaptation in healthy individuals. Future studies need to investigate if multisession ctDCS combined with training or rehabilitation interventions can induce prolonged improvement of postural balance. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Transcranial direct current stimulation on primary sensorimotor area has no effect in patients with drug-naïve restless legs syndrome: a proof-of-concept clinical trial.

Science.gov (United States)

Koo, Yong Seo; Kim, Sung Min; Lee, Chany; Lee, Byeong Uk; Moon, Ye Ji; Cho, Yong Won; Im, Chang-Hwan; Choi, Jeong Woo; Kim, Kyung Hwan; Jung, Ki-Young

2015-02-01

To evaluate the efficacy of transcranial direct current stimulation (tDCS) in people with drug-naïve restless legs syndrome (RLS). A two-week, double-blind, randomized, sham-controlled trial was performed. Thirty-three females with RLS were recruited. Participants received five sessions of tDCS using cathodal, anodal or sham stimulation. They were assessed at baseline (T0), three days (T1) and 13 days (T2) after the end of tDCS. Primary outcomes included the International RLS Group Rating Scale (IRLS) and the Clinical Global Impressions-Improvement (CGI-I). Secondary outcomes included the Patient Global Impression scale, the Pittsburgh Sleep Quality Index, the Medical Outcome Study sleep subscales, and the Beck Depression Inventory. Objective neurophysiological changes were assessed using event-related desynchronization/synchronization (ERD/ERS) of electroencephalography. The changes in the IRLS scores, as well as the responder rate in the CGI-I scale, did not differ significantly among the groups. There was also no significant difference in any of the secondary outcome measures and ERD/ERS among the groups. Transcranial direct current stimulation with electrodes on the sensorimotor areas showed no significant effect in people with drug-naïve RLS. Copyright © 2014 Elsevier B.V. All rights reserved.

Modulation of mu rhythm desynchronization during motor imagery by transcranial direct current stimulation

Directory of Open Access Journals (Sweden)

Kimura Akio

2010-06-01

Full Text Available Abstract Background The mu event-related desynchronization (ERD is supposed to reflect motor preparation and appear during motor imagery. The aim of this study is to examine the modulation of ERD with transcranial direct current stimulation (tDCS. Methods Six healthy subjects were asked to imagine their right hand grasping something after receiving a visual cue. Electroencephalograms (EEGs were recorded near the left M1. ERD of the mu rhythm (mu ERD by right hand motor imagery was measured. tDCS (10 min, 1 mA was used to modulate the cortical excitability of M1. Anodal, cathodal, and sham tDCS were tested in each subject with a randomized sequence on different days. Each condition was separated from the preceding one by more than 1 week in the same subject. Before and after tDCS, mu ERD was assessed. The motor thresholds (MT of the left M1 were also measured with transcranial magnetic stimulation. Results Mu ERD significantly increased after anodal stimulation, whereas it significantly decreased after cathodal stimulation. There was a significant correlation between mu ERD and MT. Conclusions Opposing effects on mu ERD based on the orientation of the stimulation suggest that mu ERD is affected by cortical excitability.

All-Silicon Switchable Magnetoelectric Effect through Interlayer Exchange Coupling.

Science.gov (United States)

Liu, Hang; Sun, Jia-Tao; Fu, Hui-Xia; Sun, Pei-Jie; Feng, Y P; Meng, Sheng

2017-07-19

The magnetoelectric (ME) effect originating from the effective coupling between electric field and magnetism is an exciting frontier in nanoscale science such as magnetic tunneling junction (MTJ), ferroelectric/piezoelectric heterojunctions etc. The realization of switchable ME effect under external electric field in d0 semiconducting materials of single composition is needed especially for all-silicon spintronics applications because of its natural compatibility with current industry. We employ density functional theory (DFT) to reveal that the pristine Si(111)-3×3 R30° (Si3 hereafter) reconstructed surfaces of thin films with a thickness smaller than eleven bilayers support a sizeable linear ME effect with switchable direction of magnetic moment under external electric field. This is achieved through the interlayer exchange coupling effect in the antiferromagnetic regime, where the spin-up and spin-down magnetized density is located on opposite surfaces of Si3 thin films. The obtained coefficient for the linear ME effect can be four times larger than that of ferromagnetic Fe films, which fail to have the reversal switching capabilities. The larger ME effect originates from the spin-dependent screening of the spin-polarized Dirac fermion. The prediction will promote the realization of well-controlled and switchable data storage in all-silicon electronics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improved performance of Mg–Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

International Nuclear Information System (INIS)

La, Mao; Zhou, Huaijuan; Li, Ning; Xin, Yunchuan; Sha, Ren; Bao, Shanhu; Jin, Ping

2017-01-01

Highlights: • The PTFE films was prepared for use as the top layer of Mg–Y/Pd switchable mirrors. • The PTFE as an antireflection layer to improve the luminous transmission, and also to enhance the switching durability of the switchable mirrors. • The PTFE film has a superhydrophobic surface, which endows the Mg–Y/Pd switchable mirrors with self-cleaning properties. - Abstract: The magnesium based switchable mirrors can reversibly change their optical properties between the transparent and the reflective state as a result of hydrogenation and dehydrogenation. These films can potentially be applied as new energy-saving windows, by controlling the transmittance of solar radiation through the regulation of their reflective state. In this study, magnesium–yttrium (Mg–Y) alloy thin films were prepared using a DC magnetron sputtering method. However, the luminous transmittance in the transparent state and the switching durability of switchable mirrors are too poor to satisfy practical demands. In order to improve the films switching durability, luminous transmittance and the surface functionalization, polytetrafluoroethylene (PTFE) was coated with thermal vacuum deposition for use as the top layer of Mg–Y/Pd switchable mirrors. The PTFE layer had a porous network structure and exhibited a superhydrophobic surface with a water contact angle of approximately 152°. By characterization, PTFE thin films shows the excellent protection role against the oxidization of Mg, the switching durability of the films were improved 3 times, and also shows the antireflection role the luminous transmission of films was enhanced by 7% through the top covered with PTFE.

Improved performance of Mg–Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

Energy Technology Data Exchange (ETDEWEB)

La, Mao [Department of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot, Inner Mongolia, 010020 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Zhou, Huaijuan; Li, Ning; Xin, Yunchuan [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Sha, Ren, E-mail: sr@imnu.edu.cn [Department of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot, Inner Mongolia, 010020 (China); Bao, Shanhu, E-mail: shanhu.bao@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Jin, Ping [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China)

2017-05-01

Highlights: • The PTFE films was prepared for use as the top layer of Mg–Y/Pd switchable mirrors. • The PTFE as an antireflection layer to improve the luminous transmission, and also to enhance the switching durability of the switchable mirrors. • The PTFE film has a superhydrophobic surface, which endows the Mg–Y/Pd switchable mirrors with self-cleaning properties. - Abstract: The magnesium based switchable mirrors can reversibly change their optical properties between the transparent and the reflective state as a result of hydrogenation and dehydrogenation. These films can potentially be applied as new energy-saving windows, by controlling the transmittance of solar radiation through the regulation of their reflective state. In this study, magnesium–yttrium (Mg–Y) alloy thin films were prepared using a DC magnetron sputtering method. However, the luminous transmittance in the transparent state and the switching durability of switchable mirrors are too poor to satisfy practical demands. In order to improve the films switching durability, luminous transmittance and the surface functionalization, polytetrafluoroethylene (PTFE) was coated with thermal vacuum deposition for use as the top layer of Mg–Y/Pd switchable mirrors. The PTFE layer had a porous network structure and exhibited a superhydrophobic surface with a water contact angle of approximately 152°. By characterization, PTFE thin films shows the excellent protection role against the oxidization of Mg, the switching durability of the films were improved 3 times, and also shows the antireflection role the luminous transmission of films was enhanced by 7% through the top covered with PTFE.

Randomized trial of transcranial direct current stimulation for poststroke dysphagia.

Science.gov (United States)

Suntrup-Krueger, Sonja; Ringmaier, Corinna; Muhle, Paul; Wollbrink, Andreas; Kemmling, Andre; Hanning, Uta; Claus, Inga; Warnecke, Tobias; Teismann, Inga; Pantev, Christo; Dziewas, Rainer

2018-02-01

We evaluated whether transcranial direct current stimulation (tDCS) is able to enhance dysphagia rehabilitation following stroke. Besides relating clinical effects with neuroplastic changes in cortical swallowing processing, we aimed to identify factors influencing treatment success. In this double-blind, randomized study, 60 acute dysphagic stroke patients received contralesional anodal (1mA, 20 minutes) or sham tDCS on 4 consecutive days. Swallowing function was thoroughly assessed before and after the intervention using the validated Fiberoptic Endoscopic Dysphagia Severity Scale (FEDSS) and clinical assessment. In 10 patients, swallowing-related brain activation was recorded applying magnetoencephalography before and after the intervention. Voxel-based statistical lesion pattern analysis was also performed. Study groups did not differ according to demographic data, stroke characteristics, or baseline dysphagia severity. Patients treated with tDCS showed greater improvement in FEDSS than the sham group (1.3 vs 0.4 points, mean difference = 0.9, 95% confidence interval [CI] = 0.4-1.4, p < 0.0005). Functional recovery was accompanied by a significant increase of activation (p < 0.05) in the contralesional swallowing network after real but not sham tDCS. Regarding predictors of treatment success, for every hour earlier that treatment was initiated, there was greater improvement on the FEDSS (adjusted odds ratio = 0.99, 95% CI = 0.98-1.00, p < 0.05) in multivariate analysis. Stroke location in the right insula and operculum was indicative of worse response to tDCS (p < 0.05). Application of tDCS over the contralesional swallowing motor cortex supports swallowing network reorganization, thereby leading to faster rehabilitation of acute poststroke dysphagia. Early treatment initiation seems beneficial. tDCS may be less effective in right-hemispheric insulo-opercular stroke. Ann Neurol 2018;83:328-340. © 2018 American Neurological

Switchable capacitor and method of making the same

NARCIS (Netherlands)

Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, Hendrikus; De Raedt, Walter

2006-01-01

A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom electrode, a dielectric layer deposited on at least part of said bottom electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to

Switchable capacitor and method of making the same

NARCIS (Netherlands)

Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, Hendrikus; De Raedt, Walter

2003-01-01

A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom electrode, a dielectric layer deposited on at least part of said bottom electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to

Effects of vestibular rehabilitation combined with transcranial cerebellar direct current stimulation in patients with chronic dizziness: An exploratory study.

Science.gov (United States)

Koganemaru, Satoko; Goto, Fumiyuki; Arai, Miki; Toshikuni, Keitaro; Hosoya, Makoto; Wakabayashi, Takeshi; Yamamoto, Nobuko; Minami, Shujiro; Ikeda, Satoshi; Ikoma, Katsunori; Mima, Tatsuya

Vestibular rehabilitation is useful to alleviate chronic dizziness in patients with vestibular dysfunction. It aims to induce neuronal plasticity in the central nervous system (especially in the cerebellum) to promote vestibular compensation. Transcranial cerebellar direct current stimulation (tcDCS) reportedly enhances cerebellar function. We investigated whether vestibular rehabilitation partially combined with tcDCS is superior to the use of rehabilitation alone for the alleviation of dizziness. Patients with chronic dizziness due to vestibular dysfunction received rehabilitation concurrently with either 20-min tcDCS or sham stimulation for 5 days. Pre- and post-intervention (at 1 month) dizziness handicap inventory (DHI) scores and psychometric and motor parameters were compared. Sixteen patients completed the study. DHI scores in the tcDCS group showed significant improvement over those in the sham group (Mann-Whitney U test, p = 0.033). Vestibular rehabilitation partially combined with tcDCS appears to be a promising approach. Copyright © 2017 Elsevier Inc. All rights reserved.

Deep transcranial magnetic stimulation add-on for the treatment of auditory hallucinations: a double-blind study.

Science.gov (United States)

Rosenberg, Oded; Gersner, Roman; Klein, Limor Dinur; Kotler, Moshe; Zangen, Abraham; Dannon, Pinhas

2012-05-06

About 25% of schizophrenia patients with auditory hallucinations are refractory to pharmacotherapy and electroconvulsive therapy. We conducted a deep transcranial magnetic stimulation (TMS) pilot study in order to evaluate the potential clinical benefit of repeated left temporoparietal cortex stimulation in these patients. The results were encouraging, but a sham-controlled study was needed to rule out a placebo effect. A total of 18 schizophrenic patients with refractory auditory hallucinations were recruited, from Beer Yaakov MHC and other hospitals outpatient populations. Patients received 10 daily treatment sessions with low-frequency (1 Hz for 10 min) deep TMS applied over the left temporoparietal cortex, using the H1 coil at the intensity of 110% of the motor threshold. Procedure was either real or sham according to patient randomization. Patients were evaluated via the Auditory Hallucinations Rating Scale, Scale for the Assessment of Positive Symptoms-Negative Symptoms, Clinical Global Impressions, and Quality of Life Questionnaire. In all, 10 patients completed the treatment (10 TMS sessions). Auditory hallucination scores of both groups improved; however, there was no statistical difference in any of the scales between the active and the sham treated groups. Low-frequency deep TMS to the left temporoparietal cortex using the protocol mentioned above has no statistically significant effect on auditory hallucinations or the other clinical scales measured in schizophrenic patients. Clinicaltrials.gov identifier: NCT00564096.

Bilateral 5 Hz transcranial alternating current stimulation on fronto-temporal areas modulates resting-state EEG.

Science.gov (United States)

D'Atri, Aurora; Romano, Claudia; Gorgoni, Maurizio; Scarpelli, Serena; Alfonsi, Valentina; Ferrara, Michele; Ferlazzo, Fabio; Rossini, Paolo Maria; De Gennaro, Luigi

2017-11-15

Rhythmic non-invasive brain stimulations are promising tools to modulate brain activity by entraining neural oscillations in specific cortical networks. The aim of the study was to assess the possibility to influence the neural circuits of the wake-sleep transition in awake subjects via a bilateral transcranial alternating current stimulation at 5 Hz (θ-tACS) on fronto-temporal areas. 25 healthy volunteers participated in two within-subject sessions (θ-tACS and sham), one week apart and in counterbalanced order. We assessed the stimulation effects on cortical EEG activity (28 derivations) and self-reported sleepiness (Karolinska Sleepiness Scale). θ-tACS induced significant increases of the theta activity in temporo-parieto-occipital areas and centro-frontal increases in the alpha activity compared to sham but failed to induce any online effect on sleepiness. Since the total energy delivered in the sham condition was much less than in the active θ-tACS, the current data are unable to isolate the specific effect of entrained theta oscillatory activity per se on sleepiness scores. On this basis, we concluded that θ-tACS modulated theta and alpha EEG activity with a topography consistent with high sleep pressure conditions. However, no causal relation can be traced on the basis of the current results between these rhythms and changes on sleepiness.

Modulating phonemic fluency performance in healthy subjects with transcranial magnetic stimulation over the left or right lateral frontal cortex.

Science.gov (United States)

Smirni, Daniela; Turriziani, Patrizia; Mangano, Giuseppa Renata; Bracco, Martina; Oliveri, Massimiliano; Cipolotti, Lisa

2017-07-28

A growing body of evidence have suggested that non-invasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), can improve the performance of aphasic patients in language tasks. For example, application of inhibitory rTMS or tDCs over the right frontal lobe of dysphasic patients resulted in improved naming abilities. Several studies have also reported that in healthy controls (HC) tDCS application over the left prefrontal cortex (PFC) improve performance in naming and semantic fluency tasks. The aim of this study was to investigate in HC, for the first time, the effects of inhibitory repetitive TMS (rTMS) over left and right lateral frontal cortex (BA 47) on two phonemic fluency tasks (FAS or FPL). 44 right-handed HCs were administered rTMS or sham over the left or right lateral frontal cortex in two separate testing sessions, with a 24h interval, followed by the two phonemic fluency tasks. To account for possible practice effects, an additional 22 HCs were tested on only the phonemic fluency task across two sessions with no stimulation. We found that rTMS-inhibition over the left lateral frontal cortex significantly worsened phonemic fluency performance when compared to sham. In contrast, rTMS-inhibition over the right lateral frontal cortex significantly improved phonemic fluency performance when compared to sham. These results were not accounted for practice effects. We speculated that rTMS over the right lateral frontal cortex may induce plastic neural changes to the left lateral frontal cortex by suppressing interhemispheric inhibitory interactions. This resulted in an increased excitability (disinhibition) of the contralateral unstimulated left lateral frontal cortex, consequently enhancing phonemic fluency performance. Conversely, application of rTMS over the left lateral frontal cortex may induce a temporary, virtual lesion, with effects similar to those reported in left frontal

Do changes in spinal reflex excitability elicited by transcranial magnetic stimulation differ based on the site of cerebellar stimulation?

Science.gov (United States)

Matsugi, Akiyoshi

2018-05-06

The present study aimed to investigate whether spinal reflex excitability is influenced by the site of cerebellar transcranial magnetic stimulation (C-TMS). Fourteen healthy volunteers (mean age: 24.6 ± 6.6 years [11 men]) participated. Participants lay on a bed in the prone position, with both ankle joints fixed to prevent unwanted movement. Right tibial nerve stimulation was provided to elicit the H-reflex in the right soleus muscle. Conditioning transcranial magnetic stimulation (TMS) was delivered at one of the following sites 110 ms prior to tibial stimulation: right, central, or left cerebellum; midline parietal (Pz) region; or sham stimulation. A total of 10 test trials were included for each condition, in random order. The unconditioned and conditioned H-reflexes were measured during random inter-test trials, and the cerebellar spinal facilitation (CSpF) ratios for each site were calculated (the ratio of conditioned to unconditioned H-reflexes). CSpF ratios were compared among TMS sites. CSpF ratios were significantly higher at cerebellar sites than at the Pz site or during sham stimulation. However, there was no significant difference in CSpF ratio among cerebellar sites. TMS conditioning over any part of the cerebellum facilitated the excitability of the spinal motoneuron pool. Facilitation of the H-reflex due to C-TMS may involve the effects of the bilateral descending tract of the spinal cord on the spinal motoneuron pool. Alternatively, direct brainstem stimulation may have activated portions of the bilateral descending tract of the spinal cord.

Self-Administered Domiciliary tDCS Treatment for Tinnitus: A Double-Blind Sham-Controlled Study.

Directory of Open Access Journals (Sweden)

Petteri Hyvärinen

Full Text Available Transcranial direct current stimulation (tDCS has shown potential for providing tinnitus relief, although positive effects have usually been observed only during a short time period after treatment. In recent studies the focus has turned from one-session experiments towards multi-session treatment studies investigating long-term outcomes with double-blinded and sham-controlled study designs. Traditionally, tDCS has been administered in a clinical setting by a healthcare professional but in studies involving multiple treatment sessions, often a trade-off has to be made between sample size and the amount of labor needed to run the trial. Also, as the number of required visits to the clinic increases, the dropout rate is likely to rise proportionally.The aim of the current study was to find out if tDCS treatment for tinnitus could be patient-administered in a domiciliary setting and whether the results would be comparable to those from in-hospital treatment studies. Forty-three patients with chronic (> 6 months tinnitus were involved in the study, and data on 35 out of these patients were included in final analysis. Patients received 20 minutes of left temporal area anodal (LTA or bifrontal tDCS stimulation (2 mA or sham stimulation (0.3 mA for ten consecutive days. An overall reduction in the main outcome measure, Tinnitus Handicap Inventory (THI, was found (mean change -5.0 points, p < 0.05, but there was no significant difference between active and sham treatment outcomes. Patients found the tDCS treatment easy to administer and they all tolerated it well. In conclusion, self-administered domiciliary tDCS treatment for tinnitus was found safe and feasible and gave outcome results similar to recent randomized controlled long-term treatment trials. The results suggest better overall treatment response-as measured by THI-with domiciliary treatment than with in-hospital treatment, but this advantage is not related to the tDCS variant. The study

Constraint-Induced Movement Therapy Combined with Transcranial Direct Current Stimulation over Premotor Cortex Improves Motor Function in Severe Stroke: A Pilot Randomized Controlled Trial

Directory of Open Access Journals (Sweden)

Suellen M. Andrade

2017-01-01

Full Text Available Objective. We compared the effects of transcranial direct current stimulation at different cortical sites (premotor and motor primary cortex combined with constraint-induced movement therapy for treatment of stroke patients. Design. Sixty patients were randomly distributed into 3 groups: Group A, anodal stimulation on premotor cortex and constraint-induced movement therapy; Group B, anodal stimulation on primary motor cortex and constraint-induced movement therapy; Group C, sham stimulation and constraint-induced movement therapy. Evaluations involved analysis of functional independence, motor recovery, spasticity, gross motor function, and muscle strength. Results. A significant improvement in primary outcome (functional independence after treatment in the premotor group followed by primary motor group and sham group was observed. The same pattern of improvement was highlighted among all secondary outcome measures regarding the superior performance of the premotor group over primary motor and sham groups. Conclusions. Premotor cortex can contribute to motor function in patients with severe functional disabilities in early stages of stroke. This study was registered in ClinicalTrials.gov database (NCT 02628561.

Safety and acceptability of transcranial direct current stimulation for the acute treatment of major depressive episodes: Analysis of individual patient data.

Science.gov (United States)

Moffa, Adriano H; Brunoni, André R; Fregni, Felipe; Palm, Ulrich; Padberg, Frank; Blumberger, Daniel M; Daskalakis, Zafiris J; Bennabi, Djamila; Haffen, Emmanuel; Alonzo, Angelo; Loo, Colleen K

2017-10-15

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation modality that has been increasingly used for major depressive disorder (MDD) treatment. Although studies in healthy volunteers showed that the technique is well-tolerated, tDCS safety and acceptability have not been sufficiently explored in patients with MDD. We collected individual patient data from 6 randomized clinical trials that had been previously identified in a systematic review and meta-analysis. Primary outcomes were safety (rate of adverse events) and acceptability (rate of dropouts). Secondary outcomes were clinical, demographic and treatment predictors of the primary outcomes. Dropout rates between active (8.8%) and sham (12%) groups were not significantly different (OR= 0.7, p=0.38). Adverse event rates between active (73.5%) and sham (68.3%) groups were not significantly different (OR= 1.4, p= 0.23). Higher current densities were associated with lower adverse event rates. Dropout reasons were not systematically reported and adverse events were not collected using questionnaires standardized across studies. Active tDCS is as acceptable and safe as sham tDCS, as found in randomized clinical trials of MDD. Copyright © 2017. Published by Elsevier B.V.

Surface EEG-Transcranial Direct Current Stimulation (tDCS) Closed-Loop System.

Science.gov (United States)

Leite, Jorge; Morales-Quezada, Leon; Carvalho, Sandra; Thibaut, Aurore; Doruk, Deniz; Chen, Chiun-Fan; Schachter, Steven C; Rotenberg, Alexander; Fregni, Felipe

2017-09-01

Conventional transcranial direct current stimulation (tDCS) protocols rely on applying electrical current at a fixed intensity and duration without using surrogate markers to direct the interventions. This has led to some mixed results; especially because tDCS induced effects may vary depending on the ongoing level of brain activity. Therefore, the objective of this preliminary study was to assess the feasibility of an EEG-triggered tDCS system based on EEG online analysis of its frequency bands. Six healthy volunteers were randomized to participate in a double-blind sham-controlled crossover design to receive a single session of 10[Formula: see text]min 2[Formula: see text]mA cathodal and sham tDCS. tDCS trigger controller was based upon an algorithm designed to detect an increase in the relative beta power of more than 200%, accompanied by a decrease of 50% or more in the relative alpha power, based on baseline EEG recordings. EEG-tDCS closed-loop-system was able to detect the predefined EEG magnitude deviation and successfully triggered the stimulation in all participants. This preliminary study represents a proof-of-concept for the development of an EEG-tDCS closed-loop system in humans. We discuss and review here different methods of closed loop system that can be considered and potential clinical applications of such system.

Adaptive threshold hunting for the effects of transcranial direct current stimulation on primary motor cortex inhibition.

Science.gov (United States)

Mooney, Ronan A; Cirillo, John; Byblow, Winston D

2018-06-01

Primary motor cortex excitability can be modulated by anodal and cathodal transcranial direct current stimulation (tDCS). These neuromodulatory effects may, in part, be dependent on modulation within gamma-aminobutyric acid (GABA)-mediated inhibitory networks. GABAergic function can be quantified non-invasively using adaptive threshold hunting paired-pulse transcranial magnetic stimulation (TMS). The previous studies have used TMS with posterior-anterior (PA) induced current to assess tDCS effects on inhibition. However, TMS with anterior-posterior (AP) induced current in the brain provides a more robust measure of GABA-mediated inhibition. The aim of the present study was to assess the modulation of corticomotor excitability and inhibition after anodal and cathodal tDCS using TMS with PA- and AP-induced current. In 16 young adults (26 ± 1 years), we investigated the response to anodal, cathodal, and sham tDCS in a repeated-measures double-blinded crossover design. Adaptive threshold hunting paired-pulse TMS with PA- and AP-induced current was used to examine separate interneuronal populations within M1 and their influence on corticomotor excitability and short- and long-interval inhibition (SICI and LICI) for up to 60 min after tDCS. Unexpectedly, cathodal tDCS increased corticomotor excitability assessed with AP (P = 0.047) but not PA stimulation (P = 0.74). SICI AP was reduced after anodal tDCS compared with sham (P = 0.040). Pearson's correlations indicated that SICI AP and LICI AP modulation was associated with corticomotor excitability after anodal (P = 0.027) and cathodal tDCS (P = 0.042). The after-effects of tDCS on corticomotor excitability may depend on the direction of the TMS-induced current used to make assessments, and on modulation within GABA-mediated inhibitory circuits.

Modulation of Isometric Quadriceps Strength in Soccer Players With Transcranial Direct Current Stimulation: A Crossover Study.

Science.gov (United States)

Vargas, Valentine Z; Baptista, Abrahão F; Pereira, Guilherme O C; Pochini, Alberto C; Ejnisman, Benno; Santos, Marcelo B; João, Silvia M A; Hazime, Fuad A

2018-05-01

Vargas, VZ, Baptista, AF, Pereira, GOC, Pochini, AC, Ejnisman, B, Santos, MB, João, SMA, and Hazime, FA. Modulation of isometric quadriceps strength in soccer players with transcranial direct current stimulation: a crossover study. J Strength Cond Res 32(5): 1336-1341, 2018-The aim of this study was to evaluate the effect of transcranial direct current stimulation (tDCS) on the maximum isometric muscle contraction (MVIC) of the knee extensors in soccer players at the preprofessional level. Twenty female soccer players aged 15-17 years (mean = 16.1; SD = 0.9) with 5.2 ± 2.6 years of training were randomly divided into 2 groups to receive either active or sham tDCS in a single session (2 mA; 0.057 mA·cm). The MVIC of the knee extensors was evaluated in both lower limbs by manual dynamometry in 5 sets of contractions divided into 4 blocks: (a) prestimulation, (b) during tDCS, (c) 30 minutes after tDCS, and (d) 60 minutes after tDCS. After an interval of 7 days, the groups were evaluated again, and the type of initial stimulation was inverted between participants. The MVIC of the knee extensors increased significantly during active tDCS (dominant limb (DL) = 0.4; IC = 0.1-0.8 N·Kg), 30 minutes after active tDCS (DL = 0.9; IC 0.4-1.4 N·Kg), and 60 minutes after active tDCS (DL = 1.0; IC 0.3-1.6 N·Kg) but not for sham tDCS. Our conclusion was that tDCS temporarily increases isometric quadriceps strength in adolescent female soccer players, which may be useful for both strength training and rehabilitation.

Effect of Transcranial Direct Current Stimulation in Patients With Tinnitus: A Meta-Analysis and Systematic Review.

Science.gov (United States)

Wang, Tang-Chuan; Tyler, Richard S; Chang, Ta-Yuan; Chen, Jui-Cheng; Lin, Chia-Der; Chung, Hsiung-Kwang; Tsou, Yung-An

2018-02-01

Subjective tinnitus is a phantom sensation experienced without any external source of sound that profoundly impacts the quality of life. Some investigations have claimed that transcranial direct current stimulation (tDCS) reduces tinnitus, but studies on tDCS have demonstrated variable results. This meta-analysis aimed to examine the effect of tDCS on patients with tinnitus. We searched for articles published through January 5, 2016, in Medline, Cochrane, EMBASE, and Google Scholar using the following keywords: tinnitus, transcranial direct current stimulation, and tDCS. The study outcomes were change in magnitude estimates of loudness (loudness), tinnitus-related distress (distress), and Tinnitus Handicap Inventory (THI). Pooled results demonstrated that tDCS did not have a beneficial effect on loudness (pooled standardized difference in means = 0.674, 95% CI, -0.089 to 1.437, P = .083). Further, the pooled results demonstrated a greater reduction in distress for the tDCS group (pooled standardized difference in means = 0.634, 95% CI, 0.021-1.247, P = .043). We conclude that the pooled results demonstrated a greater reduction in distress for groups treated with tDCS as compared with those administered a sham treatment.

Anodal transcranial direct current stimulation over right dorsolateral prefrontal cortex alters decision making during approach-avoidance conflict.

Science.gov (United States)

Chrysikou, Evangelia G; Gorey, Claire; Aupperle, Robin L

2017-03-01

Approach-avoidance conflict (AAC) refers to situations associated with both rewarding and threatening outcomes. The AAC task was developed to measure AAC decision-making. Approach behavior during this task has been linked to self-reported anxiety sensitivity and has elicited anterior cingulate, insula, caudate and right dorsolateral prefrontal cortex (dlPFC) activity, with right lateral PFC tracking the extent of approach behavior. Guided by these results, we used excitatory transcranial direct current stimulation (tDCS) to demonstrate the causal involvement of right dlPFC in AAC decision-making. Participants received anodal tDCS at 1.5mA over either left or right dlPFC or sham stimulation, while performing the AAC task and a control short-term memory task. Analyses of variance (ANOVA) revealed that for individuals with high anxiety sensitivity excitatory right (but not left or sham) dlPFC stimulation elicited measurable decreases in approach behavior during conflict. Excitatory left (but not right or sham) dlPFC simulation improved performance on the control task. These results support a possible asymmetry between the contributions of right and left dlPFC to AAC resolution during emotional decision-making. Increased activity in right dlPFC may contribute to anxiety-related symptoms and, as such, serve as a neurobehavioral target of anxiolytic treatments aiming to decrease avoidance behavior. © The Author (2016). Published by Oxford University Press.

Time- and task-dependent non-neural effects of real and sham TMS.

Directory of Open Access Journals (Sweden)

Felix Duecker

Full Text Available Transcranial magnetic stimulation (TMS is widely used in experimental brain research to manipulate brain activity in humans. Next to the intended neural effects, every TMS pulse produces a distinct clicking sound and sensation on the head which can also influence task performance. This necessitates careful consideration of control conditions in order to ensure that behavioral effects of interest can be attributed to the neural consequences of TMS and not to non-neural effects of a TMS pulse. Surprisingly, even though these non-neural effects of TMS are largely unknown, they are often assumed to be unspecific, i.e. not dependent on TMS parameters. This assumption is inherent to many control strategies in TMS research but has recently been challenged on empirical grounds. Here, we further develop the empirical basis of control strategies in TMS research. We investigated the time-dependence and task-dependence of the non-neural effects of TMS and compared real and sham TMS over vertex. Critically, we show that non-neural TMS effects depend on a complex interplay of these factors. Although TMS had no direct neural effects, both pre- and post-stimulus TMS time windows modulated task performance on both a sensory detection task and a cognitive angle judgment task. For the most part, these effects were quantitatively similar across tasks but effect sizes were clearly different. Moreover, the effects of real and sham TMS were almost identical with interesting exceptions that shed light on the relative contribution of auditory and somato-sensory aspects of a TMS pulse. Knowledge of such effects is of critical importance for the interpretation of TMS experiments and helps deciding what constitutes an appropriate control condition. Our results broaden the empirical basis of control strategies in TMS research and point at potential pitfalls that should be avoided.

2004 Survey of United States architects on the subject of switchable glazings

International Nuclear Information System (INIS)

Sottile, G.M.

2005-01-01

The 21st century has ushered in an era marked by the growing integration of technology and other scientific advances into commercial buildings and residential homes. Of particular interest to many architects, developers and builders are 'switchable' glazing, a new category of technologically advanced glass and plastic building materials that can be used to control light, glare and heat entering an office or a home. Interest in switchable glazing technology is influenced by a variety of factors, including a growing movement to offer sustainable, energy-efficient building solutions, and the emerging desire by users to maintain greater control over their working and living environments. This paper examines the movement toward sustainable development and the end-user needs that are driving it. Further, it presents the results of a proprietary survey research study of United States architects on the subject of switchable glazing. This study includes an examination of the attributes most desired by architects regarding smart window technology, and provides additional insight into the potential application of this smart material to the building community

Transcranial direct current stimulation of the left dorsolateral prefrontal cortex shifts preference of moral judgments.

Directory of Open Access Journals (Sweden)

Maria Kuehne

Full Text Available Attitude to morality, reflecting cultural norms and values, is considered unique to human social behavior. Resulting moral behavior in a social environment is controlled by a widespread neural network including the dorsolateral prefrontal cortex (DLPFC, which plays an important role in decision making. In the present study we investigate the influence of neurophysiological modulation of DLPFC reactivity by means of transcranial direct current stimulation (tDCS on moral reasoning. For that purpose we administered anodal, cathodal, and sham stimulation of the left DLPFC while subjects judged the appropriateness of hard moral personal dilemmas. In contrast to sham and cathodal stimulation, anodal stimulation induced a shift in judgment of personal moral dilemmas towards more non-utilitarian actions. Our results demonstrate that alterations of left DLPFC activity can change moral judgments and, in consequence, provide a causal link between left DLPFC activity and moral reasoning. Most important, the observed shift towards non-utilitarian actions suggests that moral decision making is not a permanent individual trait but can be manipulated; consequently individuals with boundless, uncontrollable, and maladaptive moral behavior, such as found in psychopathy, might benefit from neuromodulation-based approaches.

Switchable antifouling coatings and uses thereof

Science.gov (United States)

Denton, Michele L. Baca; Dirk, Shawn M.; Johnson, Ross Stefan

2017-02-28

The present invention relates to antifouling coatings capable of being switched by using heat or ultraviolet light. Prior to switching, the coating includes an onium cation component having antimicrobial and antibacterial properties. Upon switching, the coating is converted to a conjugated polymer state, and the cationic component is released with any adsorbed biofilm layer. Thus, the coatings herein have switchable and releasable properties. Methods of making and using such coatings are also described.

Single-particle properties from Kohn-Sham Green's functions

International Nuclear Information System (INIS)

Bhattacharyya, Anirban; Furnstahl, R.J.

2005-01-01

An effective action approach to Kohn-Sham density functional theory is used to illustrate how the exact Green's function can be calculated in terms of the Kohn-Sham Green's function. An example based on Skyrme energy functionals shows that single-particle Kohn-Sham spectra can be improved by adding sources used to construct the energy functional

Transcranial Direct Current Stimulation of Frontal Cortex Decreases Performance on the WAIS-IV Intelligence Test

Science.gov (United States)

Sellers, Kristin K.; Mellin, Juliann M.; Lustenberger, Caroline M.; Boyle, Michael R.; Lee, Won Hee; Peterchev, Angel V.; Frohlich, Flavio

2015-01-01

Transcranial direct current stimulation (tDCS) modulates excitability of motor cortex. However, there is conflicting evidence about the efficacy of this non-invasive brain stimulation modality to modulate performance on cognitive tasks. Previous work has tested the effect of tDCS on specific facets of cognition and executive processing. However, no randomized, double-blind, sham-controlled study has looked at the effects of tDCS on a comprehensive battery of cognitive processes. The objective of this study was to test if tDCS had an effect on performance on a comprehensive assay of cognitive processes, a standardized intelligence quotient (IQ) test. The study consisted of two substudies and followed a double-blind, between-subjects, sham-controlled design. In total, 41 healthy adult participants completed the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV) as a baseline measure. At least one week later, participants in substudy 1 received either bilateral tDCS (anodes over both F4 and F3, cathode over Cz, 2mA at each anode for 20 minutes) or active sham tDCS (2mA for 40 seconds), and participants in substudy 2 received either right or left tDCS (anode over either F4 or F3, cathode over Cz, 2mA for 20 minutes). In both studies, the WAIS-IV was immediately administered following stimulation to assess for performance differences induced by bilateral and unilateral tDCS. Compared to sham stimulation, right, left, and bilateral tDCS reduced improvement between sessions on Full Scale IQ and the Perceptual Reasoning Index. This demonstration that frontal tDCS selectively degraded improvement on specific metrics of the WAIS-IV raises important questions about the often proposed role of tDCS in cognitive enhancement. PMID:25934490

Switchable Bragg gratings

DEFF Research Database (Denmark)

Marckmann, Carl Johan

2003-01-01

Research Center (MIC) at the Technical University of Denmark. The Bragg gratings were fabricated at COM using UV irradiation of the planar waveguides using the phase mask method. The induction of a frozen-in DC electric field into the samples was performed by thermal poling of the Bragg gratings...... layers, it becam possible to investigate the symmetry properties of the third-order nonlinearities. Contrary to the expectations for an amorphous material, the measurements indicated an almost polarization independent third-order nonlinearity - the most probable explanation being electrostriction......The subject of this ph.d. thesis was the development of an electrically switchable Bragg grating made in an optical waveguide using thermal poling to be applied within optical telecommunication systems. The planar waveguides used in this thesis were fabricated at the Micro- and Nanotechnology...

Switchable polarity solvent for liquid phase microextraction of Cd(II) as pyrrolidinedithiocarbamate chelates from environmental samples

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, Erkan, E-mail: kimyager_erkan@hotmail.com; Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr

2015-07-30

A switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO{sub 2} (Dry ice) via proton transfer reaction has been used for the microextraction of cadmium(II) as pyrrolidinedithiocarbamate (APDC) chelate. Cd(II)-APDC chelate was extracted into the switchable polarity solvent drops by adding 2 mL 10 M sodium hydroxide solution. Analytical parameters affecting the complex formation and microextraction efficiency such as pH, amount of ligand, volume of switchable polarity solvent and NaOH, sample volume were optimized. The effects of foreign ions were found tolerably. Under optimum conditions, the detection limit was 0.16 μg L{sup −1} (3Sb/m, n = 7) and the relative standard deviation was 5.4% (n = 7). The method was validated by the analysis of certified reference materials (TMDA-51.3 fortified water, TMDA-53.3 fortified water and SPS-WW2 waste water, 1573a Tomato Leaves and Oriental Basma Tobacco Leaves (INCT-OBTL-5)) and addition/recovery tests. The method was successfully applied to determination of cadmium contents of water, vegetable, fruit and cigarette samples. - Highlights: • Switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO{sub 2}. • The switchable polarity solvent has been used for the microextraction of cadmium(II). • The important factors were optimized. • The method was applied to determination of cadmium in real samples.

Real-Time Prediction of Observed Action Requires Integrity of the Dorsal Premotor Cortex: Evidence From Repetitive Transcranial Magnetic Stimulation.

Science.gov (United States)

Brich, Louisa F M; Bächle, Christine; Hermsdörfer, Joachim; Stadler, Waltraud

2018-01-01

Studying brain mechanisms underlying the prediction of observed action, the dorsal premotor cortex (PMd) has been suggested a key area. The present study probed this notion using repetitive transcranial magnetic stimulation (rTMS) to test whether interference in this area would affect the accuracy in predicting the time course of object directed actions performed with the right hand. Young and healthy participants observed actions in short videos. These were briefly occluded from view for 600 ms and resumed immediately afterwards. The task was to continue the action mentally and to indicate after each occlusion, whether the action was resumed at the right moment (condition in-time) or shifted. In a first run, single-pulse transcranial magnetic stimulation (sTMS) was delivered over the left primary hand-area during occlusion. In the second run, rTMS over the left PMd was applied during occlusion in half of the participants [experimental group (EG)]. The control group (CG) received sham-rTMS over the same area. Under rTMS, the EG predicted less trials correctly than in the sTMS run. Sham-rTMS in the CG had no effects on prediction. The interference in PMd interacted with the type of manipulation applied to the action's time course occasionally during occlusion. The performance decrease of the EG was most pronounced in conditions in which the continuations after occlusions were too late in the action's course. The present results extend earlier findings suggesting that real-time action prediction requires the integrity of the PMd. Different functional roles of this area are discussed. Alternative interpretations consider either simulation of specific motor programming functions or the involvement of a feature-unspecific predictor.

Enhanced motor learning with bilateral transcranial direct current stimulation: Impact of polarity or current flow direction?

Science.gov (United States)

Naros, Georgios; Geyer, Marc; Koch, Susanne; Mayr, Lena; Ellinger, Tabea; Grimm, Florian; Gharabaghi, Alireza

2016-04-01

Bilateral transcranial direct current stimulation (TDCS) is superior to unilateral TDCS when targeting motor learning. This effect could be related to either the current flow direction or additive polarity-specific effects on each hemisphere. This sham-controlled randomized study included fifty right-handed healthy subjects in a parallel-group design who performed an exoskeleton-based motor task of the proximal left arm on three consecutive days. Prior to training, we applied either sham, right anodal (a-TDCS), left cathodal (c-TDCS), concurrent a-TDCS and c-TDCS with two independent current sources and return electrodes (double source (ds)-TDCS) or classical bilateral stimulation (bi-TDCS). Motor performance improved over time for both unilateral (a-TDCS, c-TDCS) and bilateral (bi-TDCS, ds-TDCS) TDCS montages. However, only the two bilateral paradigms led to an improvement of the final motor performance at the end of the training period as compared to the sham condition. There was no difference between the two bilateral stimulation conditions (bi-TDCS, ds-TDCS). Bilateral TDCS is more effective than unilateral stimulation due to its polarity-specific effects on each hemisphere rather than due to its current flow direction. This study is the first systematic evaluation of stimulation polarity and current flow direction of bi-hemispheric motor cortex TDCS on motor learning of proximal upper limb muscles. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Effect of Intermediate-Frequency Repetitive Transcranial Magnetic Stimulation on Recovery following Traumatic Brain Injury in Rats

Directory of Open Access Journals (Sweden)

Leticia Verdugo-Diaz

2017-01-01

Full Text Available Traumatic brain injury (TBI represents a significant public health concern and has been associated with high rates of morbidity and mortality. Although several research groups have proposed the use of repetitive transcranial magnetic stimulation (rTMS to enhance neuroprotection and recovery in patients with TBI, few studies have obtained sufficient evidence regarding its effects in this population. Therefore, we aimed to analyze the effect of intermediate-frequency rTMS (2 Hz on behavioral and histological recovery following TBI in rats. Male Wistar rats were divided into six groups: three groups without TBI (no manipulation, movement restriction plus sham rTMS, and movement restriction plus rTMS and three groups subjected to TBI (TBI only, TBI plus movement restriction and sham rTMS, and TBI plus movement restriction and rTMS. The movement restriction groups were included so that rTMS could be applied without anesthesia. Our results indicate that the restriction of movement and sham rTMS per se promotes recovery, as measured using a neurobehavioral scale, although rTMS was associated with faster and superior recovery. We also observed that TBI caused alterations in the CA1 and CA3 subregions of the hippocampus, which are partly restored by movement restriction and rTMS. Our findings indicated that movement restriction prevents damage caused by TBI and that intermediate-frequency rTMS promotes behavioral and histologic recovery after TBI.

Deep transcranial magnetic stimulation add-on for the treatment of auditory hallucinations: a double-blind study

Directory of Open Access Journals (Sweden)

Rosenberg Oded

2012-05-01

Full Text Available Abstract Background About 25% of schizophrenia patients with auditory hallucinations are refractory to pharmacotherapy and electroconvulsive therapy. We conducted a deep transcranial magnetic stimulation (TMS pilot study in order to evaluate the potential clinical benefit of repeated left temporoparietal cortex stimulation in these patients. The results were encouraging, but a sham-controlled study was needed to rule out a placebo effect. Methods A total of 18 schizophrenic patients with refractory auditory hallucinations were recruited, from Beer Yaakov MHC and other hospitals outpatient populations. Patients received 10 daily treatment sessions with low-frequency (1 Hz for 10 min deep TMS applied over the left temporoparietal cortex, using the H1 coil at the intensity of 110% of the motor threshold. Procedure was either real or sham according to patient randomization. Patients were evaluated via the Auditory Hallucinations Rating Scale, Scale for the Assessment of Positive Symptoms-Negative Symptoms, Clinical Global Impressions, and Quality of Life Questionnaire. Results In all, 10 patients completed the treatment (10 TMS sessions. Auditory hallucination scores of both groups improved; however, there was no statistical difference in any of the scales between the active and the sham treated groups. Conclusions Low-frequency deep TMS to the left temporoparietal cortex using the protocol mentioned above has no statistically significant effect on auditory hallucinations or the other clinical scales measured in schizophrenic patients. Trial Registration Clinicaltrials.gov identifier: NCT00564096.

Transcranial direct current stimulation over prefrontal cortex diminishes degree of risk aversion.

Science.gov (United States)

Ye, Hang; Chen, Shu; Huang, Daqiang; Wang, Siqi; Jia, Yongmin; Luo, Jun

2015-06-26

Previous studies have established that transcranial direct current stimulation (tDCS) is a powerful technique for manipulating the activity of the human cerebral cortex. Many studies have found that weighing the risks and benefits in decision-making involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC). We studied whether participants change the balance of risky and safe responses after receiving tDCS applied over the right and left prefrontal cortex. A total of 60 healthy volunteers performed a risk task while they received either anodal tDCS over the right prefrontal cortex, with cathodal over the left; anodal tDCS over the left prefrontal cortex, with cathodal over the right; or sham stimulation. The participants tended to choose less risky options after receiving sham stimulation, demonstrating that the task might be highly influenced by the "wealth effect". There was no statistically significant change after either right anodal/left cathodal or left anodal/right cathodal tDCS, indicating that both types of tDCS impact the participants' degrees of risk aversion, and therefore, counteract the wealth effect. We also found gender differences in the participants' choices. These findings extend the notion that DLPFC activity is critical for risk decision-making. Application of tDCS to the right/left DLPFC may impact a person's attitude to taking risks. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Modulation of Total Sleep Time by Transcranial Direct Current Stimulation (tDCS).

Science.gov (United States)

Frase, Lukas; Piosczyk, Hannah; Zittel, Sulamith; Jahn, Friederike; Selhausen, Peter; Krone, Lukas; Feige, Bernd; Mainberger, Florian; Maier, Jonathan G; Kuhn, Marion; Klöppel, Stefan; Normann, Claus; Sterr, Annette; Spiegelhalder, Kai; Riemann, Dieter; Nitsche, Michael A; Nissen, Christoph

2016-09-01

Arousal and sleep are fundamental physiological processes, and their modulation is of high clinical significance. This study tested the hypothesis that total sleep time (TST) in humans can be modulated by the non-invasive brain stimulation technique transcranial direct current stimulation (tDCS) targeting a 'top-down' cortico-thalamic pathway of sleep-wake regulation. Nineteen healthy participants underwent a within-subject, repeated-measures protocol across five nights in the sleep laboratory with polysomnographic monitoring (adaptation, baseline, three experimental nights). tDCS was delivered via bi-frontal target electrodes and bi-parietal return electrodes before sleep (anodal 'activation', cathodal 'deactivation', and sham stimulation). Bi-frontal anodal stimulation significantly decreased TST, compared with cathodal and sham stimulation. This effect was location specific. Bi-frontal cathodal stimulation did not significantly increase TST, potentially due to ceiling effects in good sleepers. Exploratory resting-state EEG analyses before and after the tDCS protocols were consistent with the notion of increased cortical arousal after anodal stimulation and decreased cortical arousal after cathodal stimulation. The study provides proof-of-concept that TST can be decreased by non-invasive bi-frontal anodal tDCS in healthy humans. Further elucidating the 'top-down' pathway of sleep-wake regulation is expected to increase knowledge on the fundamentals of sleep-wake regulation and to contribute to the development of novel treatments for clinical conditions of disturbed arousal and sleep.

The Joint Effects of Spatial Cueing and Transcranial Direct Current Stimulation on Visual Acuity

Directory of Open Access Journals (Sweden)

Taly Bonder

2018-02-01

Full Text Available The present study examined the mutual influence of cortical neuroenhancement and allocation of spatial attention on perception. Specifically, it explored the effects of transcranial Direct Current Stimulation (tDCS on visual acuity measured with a Landolt gap task and attentional precues. The exogenous cues were used to draw attention either to the location of the target or away from it, generating significant performance benefits and costs. Anodal tDCS applied to posterior occipital area for 15 min improved performance during stimulation, reflecting heightened visual acuity. Reaction times were lower, and accuracy was higher in the tDCS group, compared to a sham control group. Additionally, in post-stimulation trials tDCS significantly interacted with the effect of precuing. Reaction times were lower in valid cued trials (benefit and higher in invalid trials (cost compared to neutrally cued trials, the effect which was pronounced stronger in tDCS group than in sham control group. The increase of cost and benefit effects in the tDCS group was of a similar magnitude, suggesting that anodal tDCS influenced the overall process of attention orienting. The observed interaction between the stimulation of the visual cortex and precueing indicates a magnification of attention modulation.

Tunable and switchable all-fiber comb filter using a PBS-based two-stage cascaded Mach-Zehnder interferometer

Science.gov (United States)

Luo, Zhi-Chao; Luo, Ai-Ping; Xu, Wen-Cheng

2011-08-01

We propose and demonstrate a novel tunable and switchable all-fiber comb filter by employing a polarization beam splitter (PBS)-based two-stage cascaded Mach-Zehnder (M-Z) interferometer. The proposed comb filter consists of a rotatable polarizer, a fiber PBS, a non-3-dB coupler and a 3-dB coupler. By simply adjusting the polarization state of the input light, the dual-function of channel spacing tunable and wavelength switchable (interleaving) operations can be efficiently obtained. The theoretical analysis is verified by the experimental results. A comb filter with both the channel spacing tunable from 0.18 nm to 0.36 nm and the wavelength switchable functions is experimentally demonstrated.

Task-specific effect of transcranial direct current stimulation on motor learning

Directory of Open Access Journals (Sweden)

Cinthia Maria Saucedo Marquez

2013-07-01

Full Text Available Transcranial direct current stimulation (tDCS is a relatively new non-invasive brain stimulation technique that modulates neural processes. When applied to the human primary motor cortex (M1, tDCS has beneficial effects on motor skill learning and consolidation in healthy controls and in patients. However, it remains unclear whether tDCS improves motor learning in a general manner or whether these effects depend on which motor task is acquired. Here we compare whether the effect of tDCS differs when the same individual acquires (1 a Sequential Finger Tapping Task (SEQTAP and (2 a Visual Isometric Pinch Force Task (FORCE. Both tasks have been shown to be sensitive to tDCS applied over M1, however, the underlying processes mediating learning and memory formation might benefit differently from anodal-tDCS. Thirty healthy subjects were randomly assigned to an anodal-tDCS group or sham-group. Using a double-blind, sham-controlled cross-over design, tDCS was applied over M1 while subjects acquired each of the motor tasks over 3 consecutive days, with the order being randomized across subjects. We found that anodal-tDCS affected each task differently: The SEQTAP task benefited from anodal-tDCS during learning, whereas the FORCE task showed improvements only at retention. These findings suggest that anodal tDCS applied over M1 appears to have a task-dependent effect on learning and memory formation.

Switchable photosystem-II designer algae for photobiological hydrogen production

Science.gov (United States)

Lee, James Weifu

2010-01-05

A switchable photosystem-II designer algae for photobiological hydrogen production. The designer transgenic algae includes at least two transgenes for enhanced photobiological H.sub.2 production wherein a first transgene serves as a genetic switch that can controls photosystem II (PSII) oxygen evolution and a second transgene encodes for creation of free proton channels in the algal photosynthetic membrane. In one embodiment, the algae includes a DNA construct having polymerase chain reaction forward primer (302), a inducible promoter (304), a PSII-iRNA sequence (306), a terminator (308), and a PCR reverse primer (310). In other embodiments, the PSII-iRNA sequence (306) is replaced with a CF.sub.1-iRNA sequence (312), a streptomycin-production gene (314), a targeting sequence (316) followed by a proton-channel producing gene (318), or a PSII-producing gene (320). In one embodiment, a photo-bioreactor and gas-product separation and utilization system produce photobiological H.sub.2 from the switchable PSII designer alga.

Transcranial laser stimulation as neuroenhancement for attention bias modification in adults with elevated depression symptoms

Science.gov (United States)

Disner, Seth G.; Beevers, Christopher G.; Gonzalez-Lima, Francisco

2016-01-01

Background Low-level light therapy (LLLT) with transcranial laser is a non-invasive form of neuroenhancement shown to regulate neuronal metabolism and cognition. Attention bias modification (ABM) is a cognitive intervention designed to improve depression by decreasing negative attentional bias, but to date its efficacy has been inconclusive. Adjunctive neuroenhancement to augment clinical effectiveness has shown promise, particularly for individuals who respond positively to the primary intervention. Objective/Hypothesis This randomized, sham-controlled proof-of-principle study is the first to test the hypothesis that augmentative LLLT will improve the effects of ABM among adults with elevated symptoms of depression. Methods Fifty-one adult participants with elevated symptoms of depression received ABM before and after laser stimulation and were randomized to one of three conditions: right forehead, left forehead, or sham. Participants repeated LLLT two days later and were assessed for depression symptoms one and two weeks later. Results A significant three-way interaction between LLLT condition, ABM response, and time indicated that right LLLT led to greater symptom improvement among participants whose attention was responsive to ABM (i.e., attention was directed away from negative stimuli). Minimal change in depression was observed in the left and sham LLLT. Conclusions The beneficial effects of ABM on depression symptoms may be enhanced when paired with adjunctive interventions such as right prefrontal LLLT; however, cognitive response to ABM likely moderates the impact of neuroenhancement. The results suggest that larger clinical trials examining the efficacy of using photoneuromodulation to augment cognitive training are warranted. PMID:27267860

Enhancing performance in numerical magnitude processing and mental arithmetic using transcranial Direct Current Stimulation (tDCS

Directory of Open Access Journals (Sweden)

Tobias U. Hauser

2013-06-01

Full Text Available The ability to accurately process numerical magnitudes and solve mental arithmetic is of highest importance for schooling and professional career. Although impairments in these domains in disorders such as developmental dyscalculia (DD are highly detrimental, remediation is still sparse. In recent years, transcranial brain stimulation methods such as transcranial Direct Current Stimulation (tDCS have been suggested as a treatment for various neurologic and neuropsychiatric disorders. The posterior parietal cortex (PPC is known to be crucially involved in numerical magnitude processing and mental arithmetic. In this study, we evaluated whether tDCS has a beneficial effect on numerical magnitude processing and mental arithmetic. Due to the unclear lateralization, we stimulated the left, right as well as both hemispheres simultaneously in two experiments. We found that left anodal tDCS significantly enhanced performance in a number comparison and a subtraction task, while bilateral and right anodal tDCS did not induce any improvements compared to sham. Our findings demonstrate that the left PPC is causally involved in numerical magnitude processing and mental arithmetic. Furthermore, we show that these cognitive functions can be enhanced by means of tDCS. These findings encourage to further investigate the beneficial effect of tDCS in the domain of mathematics in healthy and impaired humans.

Transcranial Direct Current Stimulation in Neurodegenerative Disease

Directory of Open Access Journals (Sweden)

Argye E. Hillis

2014-04-01

Full Text Available We review rationale, challenges, study designs, reported results, and future directions in the use of transcranial direct cranial stimulation (tDCS in neurodegenerative disease, focusing on treatment of spelling in primary progressive aphasia (PPA. Rationale Evidence from both animal studies and human studies indicates that anodal and cathodal tDCS over the brain result in a temporary change in membrane potentials, reducing the threshold for long-term potentiation of neurons in the affected area. This may allow unaffected brain regions to assume functions of diseased regions. Challenges Special challenges in treating individuals with progressive conditions include altered goals of treatment and the possibility that participants may accumulate new deficits over the course of the treatment program that interfere with their ability to understand, retain, or cooperate with aspects of the program. The most serious challenge – particularly for single case designs - is that there may be no stable baseline against which to measure change with treatment. Thus, it is essential to demonstrate that treatment results in a statistically significant change in the slope of decline or improvement. Therefore, demonstration of a significant difference between tDCS and control (sham requires either a large number of participants or a large effect size. Designs The choice of a treatment design reflects these limitations. Group studies with a randomized, double-blind, sham control trial design (without cross-over provide the greatest power to detect a difference between intervention and control conditions, with the fewest participants. A cross-over design, in which all participants (from 1 to many receive both active and sham conditions, in randomized order, requires a larger effect size for the active condition relative to the control condition (or little to no maintenance of treatment gains or carry-over effect to show significant differences between treatment

Electrified emotions: Modulatory effects of transcranial direct stimulation on negative emotional reactions to social exclusion.

Science.gov (United States)

Riva, Paolo; Romero Lauro, Leonor J; Vergallito, Alessandra; DeWall, C Nathan; Bushman, Brad J

2015-01-01

Social exclusion, ostracism, and rejection can be emotionally painful because they thwart the need to belong. Building on studies suggesting that the right ventrolateral prefrontal cortex (rVLPFC) is associated with regulation of negative emotions, the present experiment tests the hypothesis that decreasing the cortical excitability of the rVLPFC may increase negative emotional reactions to social exclusion. Specifically, we applied cathodal transcranial direct current stimulation (tDCS) over the rVLPFC and predicted an increment of negative emotional reactions to social exclusion. In Study 1, participants were either socially excluded or included, while cathodal tDCS or sham stimulation was applied over the rVLPFC. Cathodal stimulation of rVLPFC boosted the typical negative emotional reaction caused by social exclusion. No effects emerged from participants in the inclusion condition. To test the specificity of tDCS effects over rVLPFC, in Study 2, participants were socially excluded and received cathodal tDCS or sham stimulation over a control region (i.e., the right posterior parietal cortex). No effects of tDCS stimulation were found. Our results showed that the rVLPFC is specifically involved in emotion regulation and suggest that cathodal stimulation can increase negative emotional responses to social exclusion.

Transcranial Magnetic Stimulation to Address Mild Cognitive Impairment in the Elderly: A Randomized Controlled Study

Science.gov (United States)

Drumond Marra, Hellen Livia; Myczkowski, Martin Luiz; Maia Memória, Cláudia; Arnaut, Débora; Leite Ribeiro, Philip; Sardinha Mansur, Carlos Gustavo; Lancelote Alberto, Rodrigo; Boura Bellini, Bianca; Alves Fernandes da Silva, Adriano; Ciampi de Andrade, Daniel; Teixeira, Manoel Jacobsen; Forlenza, Orestes Vicente; Marcolin, Marco Antonio

2015-01-01

Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique with potential to improve memory. Mild cognitive impairment (MCI), which still lacks a specific therapy, is a clinical syndrome associated with increased risk of dementia. This study aims to assess the effects of high-frequency repetitive TMS (HF rTMS) on everyday memory of the elderly with MCI. We conducted a double-blinded randomized sham-controlled trial using rTMS over the left dorsolateral prefrontal cortex (DLPFC). Thirty-four elderly outpatients meeting Petersen's MCI criteria were randomly assigned to receive 10 sessions of either active TMS or sham, 10 Hz rTMS at 110% of motor threshold, 2,000 pulses per session. Neuropsychological assessment at baseline, after the last session (10th) and at one-month follow-up, was applied. ANOVA on the primary efficacy measure, the Rivermead Behavioural Memory Test, revealed a significant group-by-time interaction (p = 0.05), favoring the active group. The improvement was kept after one month. Other neuropsychological tests were heterogeneous. rTMS at 10 Hz enhanced everyday memory in elderly with MCI after 10 sessions. These findings suggest that rTMS might be effective as a therapy for MCI and probably a tool to delay deterioration. PMID:26160997

Neurotransmitters behind pain relief with transcranial magnetic stimulation - positron emission tomography evidence for release of endogenous opioids.

Science.gov (United States)

Lamusuo, S; Hirvonen, J; Lindholm, P; Martikainen, I K; Hagelberg, N; Parkkola, R; Taiminen, T; Hietala, J; Helin, S; Virtanen, A; Pertovaara, A; Jääskeläinen, S K

2017-10-01

Repetitive transcranial magnetic stimulation (rTMS) at M1/S1 cortex has been shown to alleviate neuropathic pain. To investigate the possible neurobiological correlates of cortical neurostimulation for the pain relief. We studied the effects of M1/S1 rTMS on nociception, brain dopamine D2 and μ-opioid receptors using a randomized, sham-controlled, double-blinded crossover study design and 3D-positron emission tomography (PET). Ten healthy subjects underwent active and sham rTMS treatments to the right M1/S1 cortex with E-field navigated device. Dopamine D2 and μ-receptor availabilities were assessed with PET radiotracers [ 11 C]raclopride and [ 11 C]carfentanil after each rTMS treatment. Thermal quantitative sensory testing (QST), contact heat evoked potential (CHEP) and blink reflex (BR) recordings were performed between the PET scans. μ-Opioid receptor availability was lower after active than sham rTMS (P ≤ 0.0001) suggested release of endogenous opioids in the right ventral striatum, medial orbitofrontal, prefrontal and anterior cingulate cortices, and left insula, superior temporal gyrus, dorsolateral prefrontal cortex and precentral gyrus. There were no differences in striatal dopamine D2 receptor availability between active and sham rTMS, consistent with lack of long-lasting measurable dopamine release. Active rTMS potentiated the dopamine-regulated habituation of the BR compared to sham (P = 0.02). Thermal QST and CHEP remained unchanged after active rTMS. rTMS given to M1/S1 activates the endogenous opioid system in a wide brain network associated with processing of pain and other salient stimuli. Direct enhancement of top-down opioid-mediated inhibition may partly explain the clinical analgesic effects of rTMS. Neurobiological correlates of rTMS for the pain relief are unclear. rTMS on M1/S1 with 11 C-carfentanyl-PET activates endogenous opioids. Thermal and heat pain thresholds remain unchanged. rTMS induces top-down opioid-mediated inhibition

Switchable reconfiguration of nucleic acid nanostructures by stimuli-responsive DNA machines.

Science.gov (United States)

Liu, Xiaoqing; Lu, Chun-Hua; Willner, Itamar

2014-06-17

CONSPECTUS: The base sequence in DNA dictates structural and reactivity features of the biopolymer. These properties are implemented to use DNA as a unique material for developing the area of DNA nanotechnology. The design of DNA machines represents a rapidly developing research field in the area of DNA nanotechnology. The present Account discusses the switchable reconfiguration of nucleic acid nanostructures by stimuli-responsive DNA machines, and it highlights potential applications and future perspectives of the area. Programmed switchable DNA machines driven by various fuels and antifuels, such as pH, Hg(2+) ions/cysteine, or nucleic acid strands/antistrands, are described. These include the assembly of DNA tweezers, walkers, a rotor, a pendulum, and more. Using a pH-oscillatory system, the oscillatory mechanical operation of a DNA pendulum is presented. Specifically, the synthesis and "mechanical" properties of interlocked DNA rings are described. This is exemplified with the preparation of interlocked DNA catenanes and a DNA rotaxane. The dynamic fuel-driven reconfiguration of the catenane/rotaxane structures is followed by fluorescence spectroscopy. The use of DNA machines as functional scaffolds to reconfigurate Au nanoparticle assemblies and to switch the fluorescence features within fluorophore/Au nanoparticle conjugates between quenching and surface-enhanced fluorescence states are addressed. Specifically, the fluorescence features of the different DNA machines are characterized as a function of the spatial separation between the fluorophore and Au nanoparticles. The experimental results are supported by theoretical calculations. The future development of reconfigurable stimuli-responsive DNA machines involves fundamental challenges, such as the synthesis of molecular devices exhibiting enhanced complexities, the introduction of new fuels and antifuels, and the integration of new payloads being reconfigured by the molecular devices, such as enzymes or

Left prefrontal repetitive transcranial magnetic stimulation in schizophrenia.

Science.gov (United States)

Holi, Matti M; Eronen, Markku; Toivonen, Kari; Toivonen, Päivi; Marttunen, Mauri; Naukkarinen, Hannu

2004-01-01

In a double-blind, controlled study, we examined the therapeutic effects of high-frequency left prefrontal repetitive transcranial magnetic stimulation (rTMS) on schizophrenia symptoms. A total of 22 chronic hospitalized schizophrenia patients were randomly assigned to 2 weeks (10 sessions) of real or sham rTMS. rTMS was given with the following parameters: 20 trains of 5-second 10-Hz stimulation at 100 percent motor threshold, 30 seconds apart. Effects on positive and negative symptoms, self-reported symptoms, rough neuropsychological functioning, and hormones were assessed. Although there was a significant improvement in both groups in most of the symptom measures, no real differences were found between the groups. A decrease of more than 20 percent in the total PANSS score was found in 7 control subjects but only 1 subject from the real rTMS group. There was no change in hormone levels or neuropsychological functioning, measured by the MMSE, in either group. Left prefrontal rTMS (with the used parameters) seems to produce a significant nonspecific effect of the treatment procedure but no therapeutic effect in the most chronic and severely ill schizophrenia patients.

Real-Time Prediction of Observed Action Requires Integrity of the Dorsal Premotor Cortex: Evidence From Repetitive Transcranial Magnetic Stimulation

Directory of Open Access Journals (Sweden)

Louisa F. M. Brich

2018-03-01

Full Text Available Studying brain mechanisms underlying the prediction of observed action, the dorsal premotor cortex (PMd has been suggested a key area. The present study probed this notion using repetitive transcranial magnetic stimulation (rTMS to test whether interference in this area would affect the accuracy in predicting the time course of object directed actions performed with the right hand. Young and healthy participants observed actions in short videos. These were briefly occluded from view for 600 ms and resumed immediately afterwards. The task was to continue the action mentally and to indicate after each occlusion, whether the action was resumed at the right moment (condition in-time or shifted. In a first run, single-pulse transcranial magnetic stimulation (sTMS was delivered over the left primary hand-area during occlusion. In the second run, rTMS over the left PMd was applied during occlusion in half of the participants [experimental group (EG]. The control group (CG received sham-rTMS over the same area. Under rTMS, the EG predicted less trials correctly than in the sTMS run. Sham-rTMS in the CG had no effects on prediction. The interference in PMd interacted with the type of manipulation applied to the action’s time course occasionally during occlusion. The performance decrease of the EG was most pronounced in conditions in which the continuations after occlusions were too late in the action’s course. The present results extend earlier findings suggesting that real-time action prediction requires the integrity of the PMd. Different functional roles of this area are discussed. Alternative interpretations consider either simulation of specific motor programming functions or the involvement of a feature-unspecific predictor.

Efficacy and safety of deep transcranial magnetic stimulation for major depression: a prospective multicenter randomized controlled trial.

Science.gov (United States)

Levkovitz, Yechiel; Isserles, Moshe; Padberg, Frank; Lisanby, Sarah H; Bystritsky, Alexander; Xia, Guohua; Tendler, Aron; Daskalakis, Zafiris J; Winston, Jaron L; Dannon, Pinhas; Hafez, Hisham M; Reti, Irving M; Morales, Oscar G; Schlaepfer, Thomas E; Hollander, Eric; Berman, Joshua A; Husain, Mustafa M; Sofer, Uzi; Stein, Ahava; Adler, Shmulik; Deutsch, Lisa; Deutsch, Frederic; Roth, Yiftach; George, Mark S; Zangen, Abraham

2015-02-01

Major depressive disorder (MDD) is a prevalent and disabling condition, and many patients do not respond to available treatments. Deep transcranial magnetic stimulation (dTMS) is a new technology allowing non-surgical stimulation of relatively deep brain areas. This is the first double-blind randomized controlled multicenter study evaluating the efficacy and safety of dTMS in MDD. We recruited 212 MDD outpatients, aged 22-68 years, who had either failed one to four antidepressant trials or not tolerated at least two antidepressant treatments during the current episode. They were randomly assigned to monotherapy with active or sham dTMS. Twenty sessions of dTMS (18 Hz over the prefrontal cortex) were applied during 4 weeks acutely, and then biweekly for 12 weeks. Primary and secondary efficacy endpoints were the change in the Hamilton Depression Rating Scale (HDRS-21) score and response/remission rates at week 5, respectively. dTMS induced a 6.39 point improvement in HDRS-21 scores, while a 3.28 point improvement was observed in the sham group (p=0.008), resulting in a 0.76 effect size. Response and remission rates were higher in the dTMS than in the sham group (response: 38.4 vs. 21.4%, p=0.013; remission: 32.6 vs. 14.6%, p=0.005). These differences between active and sham treatment were stable during the 12-week maintenance phase. dTMS was associated with few and minor side effects apart from one seizure in a patient where a protocol violation occurred. These results suggest that dTMS constitutes a novel intervention in MDD, which is efficacious and safe in patients not responding to antidepressant medications, and whose effect remains stable over 3 months of maintenance treatment. © 2015 World Psychiatric Association.

Transcranial direct current stimulation (tDCS) of frontal cortex decreases performance on the WAIS-IV intelligence test.

Science.gov (United States)

Sellers, Kristin K; Mellin, Juliann M; Lustenberger, Caroline M; Boyle, Michael R; Lee, Won Hee; Peterchev, Angel V; Fröhlich, Flavio

2015-09-01

Transcranial direct current stimulation (tDCS) modulates excitability of motor cortex. However, there is conflicting evidence about the efficacy of this non-invasive brain stimulation modality to modulate performance on cognitive tasks. Previous work has tested the effect of tDCS on specific facets of cognition and executive processing. However, no randomized, double-blind, sham-controlled study has looked at the effects of tDCS on a comprehensive battery of cognitive processes. The objective of this study was to test if tDCS had an effect on performance on a comprehensive assay of cognitive processes, a standardized intelligence quotient (IQ) test. The study consisted of two substudies and followed a double-blind, between-subjects, sham-controlled design. In total, 41 healthy adult participants were included in the final analysis. These participants completed the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV) as a baseline measure. At least one week later, participants in substudy 1 received either bilateral tDCS (anodes over both F4 and F3, cathode over Cz, 2 mA at each anode for 20 min) or active sham tDCS (2 mA for 40 s), and participants in substudy 2 received either right or left tDCS (anode over either F4 or F3, cathode over Cz, 2 mA for 20 min). In both studies, the WAIS-IV was immediately administered following stimulation to assess for performance differences induced by bilateral and unilateral tDCS. Compared to sham stimulation, right, left, and bilateral tDCS reduced improvement between sessions on Full Scale IQ and the Perceptual Reasoning Index. This demonstration that frontal tDCS selectively degraded improvement on specific metrics of the WAIS-IV raises important questions about the often proposed role of tDCS in cognitive enhancement. Copyright © 2015 Elsevier B.V. All rights reserved.

Priming With 1-Hz Repetitive Transcranial Magnetic Stimulation Over Contralesional Leg Motor Cortex Does Not Increase the Rate of Regaining Ambulation Within 3 Months of Stroke: A Randomized Controlled Trial.

Science.gov (United States)

Huang, Ying-Zu; Lin, Li-Fong; Chang, Kwang-Hwa; Hu, Chaur-Jong; Liou, Tsan-Hon; Lin, Yen-Nung

2018-05-01

The potential benefits of repetitive transcranial magnetic stimulation (rTMS), applied either alone or as a combination treatment, on recovery of lower limbs after stroke have been insufficiently studied. The aim of the study was to evaluate the effect of priming with 1-Hz repetitive transcranial magnetic stimulation over contralesional leg motor area with a double-cone coil before physical therapy on regaining ambulation. Thirty-eight subacute stroke patients with significant leg disabilities were randomly assigned into the experimental group or control group to receive a 15-min real or sham 1-Hz repetitive transcranial magnetic stimulation, respectively, over the contralesional motor cortex representing the quadriceps muscle followed by 45-min physical therapy for 15 sessions for 3 wks. Functional measures, motor evoked potentials, and quality of life were assessed. There was no significant difference between experimental group and control group regarding the recovery in ambulation, balance, motor functions, and activity of daily living. No significant difference was found in other functional measures and the quality of life. Only the control group displayed significantly increased cortical excitability of the contralesional hemisphere after the intervention. The present study found that insufficient evidence that contralesional priming with 1-Hz repetitive transcranial magnetic stimulation improves ambulatory and other motor functions among patients with a severe leg dysfunction in subacute stroke.

Transcranial direct current stimulation (tDCS) for treatment of major depression during pregnancy: study protocol for a pilot randomized controlled trial.

Science.gov (United States)

Vigod, Simone; Dennis, Cindy-Lee; Daskalakis, Zafiris; Murphy, Kellie; Ray, Joel; Oberlander, Tim; Somerton, Sarah; Hussain-Shamsy, Neesha; Blumberger, Daniel

2014-09-18

Women with depression in pregnancy are faced with difficult treatment decisions. Untreated, antenatal depression has serious negative implications for mothers and children. While antidepressant drug treatment is likely to improve depressive symptoms, it crosses the placenta and may pose risks to the unborn child. Transcranial direct current stimulation is a focal brain stimulation treatment that improves depressive symptoms within 3 weeks of treatment by inducing changes to brain areas involved in depression, without impacting any other brain areas, and without inducing changes to heart rate, blood pressure or core body temperature. The localized nature of transcranial direct current stimulation makes it an ideal therapeutic approach for treating depression during pregnancy, although it has never previously been evaluated in this population. We describe a pilot randomized controlled trial of transcranial direct current stimulation among women with depression in pregnancy to assess the feasibility of a larger, multicentre efficacy study. Women over 18 years of age and between 14 and 32 weeks gestation can be enrolled in the study provided they meet diagnostic criteria for a major depressive episode of at least moderate severity and have been offered but refused antidepressant medication. Participants are randomized to receive active transcranial direct current stimulation or a sham condition that is administered in 15 30-minute treatments over three weeks. Women sit upright during treatment and receive obstetrical monitoring prior to, during and after each treatment session. Depressive symptoms, treatment acceptability, and pregnancy outcomes are assessed at baseline (prior to randomization), at the end of each treatment week, every four weeks post-treatment until delivery, and at 4 and 12 weeks postpartum. Transcranial direct current stimulation is a novel therapeutic option for treating depression during pregnancy. This protocol allows for assessment of the

Time-dependent Kohn-Sham approach to quantum electrodynamics

International Nuclear Information System (INIS)

Ruggenthaler, M.; Mackenroth, F.; Bauer, D.

2011-01-01

We prove a generalization of the van Leeuwen theorem toward quantum electrodynamics, providing the formal foundations of a time-dependent Kohn-Sham construction for coupled quantized matter and electromagnetic fields. We circumvent the symmetry-causality problems associated with the action-functional approach to Kohn-Sham systems. We show that the effective external four-potential and four-current of the Kohn-Sham system are uniquely defined and that the effective four-current takes a very simple form. Further we rederive the Runge-Gross theorem for quantum electrodynamics.

Neural mechanisms underlying transcranial direct current stimulation in aphasia: A feasibility study.

Directory of Open Access Journals (Sweden)

Lena eUlm

2015-10-01

Full Text Available Little is known about the neural mechanisms by which transcranial direct current stimulation (tDCS impacts on language processing in post-stroke aphasia. This was addressed in a proof-of-principle study that explored the effects of tDCS application in aphasia during simultaneous functional magnetic resonance imaging (fMRI. We employed a single subject, cross-over, sham-tDCS controlled design and the stimulation was administered to an individualized perilesional stimulation site that was identified by a baseline fMRI scan and a picture naming task. Peak activity during the baseline scan was located in the spared left inferior frontal gyrus (IFG and this area was stimulated during a subsequent cross-over phase. tDCS was successfully administered to the target region and anodal- vs. sham-tDCS resulted in selectively increased activity at the stimulation site. Our results thus demonstrate that it is feasible to precisely target an individualized stimulation site in aphasia patients during simultaneous fMRI which allows assessing the neural mechanisms underlying tDCS application. The functional imaging results of this case report highlight one possible mechanism that may have contributed to beneficial behavioural stimulation effects in previous clinical tDCS trials in aphasia. In the future, this approach will allow identifying distinct patterns of stimulation effects on neural processing in larger cohorts of patients. This may ultimately yield information about the variability of tDCS-effects on brain functions in aphasia.

Effects of Transcranial Direct Current Stimulation, Transcranial Pulsed Current Stimulation, and Their Combination on Brain Oscillations in Patients with Chronic Visceral Pain: A Pilot Crossover Randomized Controlled Study

Directory of Open Access Journals (Sweden)

Aurore Thibaut

2017-11-01

Full Text Available ObjectiveChronic visceral pain (CVP syndromes are persistently painful disorders with a remarkable lack of effective treatment options. This study aimed at evaluating the effects of different neuromodulation techniques in patients with CVP on cortical activity, through electreocephalography (EEG and on pain perception, through clinical tests.DesignA pilot crossover randomized controlled study.SettingsOut-patient.SubjectsAdults with CVP (>3 months.MethodsParticipants received four interventions in a randomized order: (1 transcranial pulsed current stimulation (tPCS and active transcranial direct current stimulation (tDCS combined, (2 tPCS alone, (3 tDCS alone, and (4 sham condition. Resting state quantitative electroencephalography (qEEG and pain assessments were performed before and after each intervention. Results were compared with a cohort of 47 healthy controls.ResultsWe enrolled six patients with CVP for a total of 21 visits completed. Compared with healthy participants, patients with CVP showed altered cortical activity characterized by increased power in theta, alpha and beta bands, and a significant reduction in the alpha/beta ratio. Regarding tES, the combination of tDCS with tPCS had no effect on power in any of the bandwidths, nor brain regions. Comparing tPCS with tDCS alone, we found that tPCS induced higher increase in power within the theta and alpha bandwidths.ConclusionThis study confirms that patients with CVP present abnormal EEG-indexed cortical activity compared with healthy controls. Moreover, we showed that combining two types of neurostimulation techniques had no effect, whereas the two interventions, when applied individually, have different neural signatures.

Effects of Transcranial Direct Current Stimulation, Transcranial Pulsed Current Stimulation, and Their Combination on Brain Oscillations in Patients with Chronic Visceral Pain: A Pilot Crossover Randomized Controlled Study.

Science.gov (United States)

Thibaut, Aurore; Russo, Cristina; Hurtado-Puerto, Aura Maria; Morales-Quezada, Jorge Leon; Deitos, Alícia; Petrozza, John Christopher; Freedman, Steven; Fregni, Felipe

2017-01-01

Chronic visceral pain (CVP) syndromes are persistently painful disorders with a remarkable lack of effective treatment options. This study aimed at evaluating the effects of different neuromodulation techniques in patients with CVP on cortical activity, through electreocephalography (EEG) and on pain perception, through clinical tests. A pilot crossover randomized controlled study. Out-patient. Adults with CVP (>3 months). Participants received four interventions in a randomized order: (1) transcranial pulsed current stimulation (tPCS) and active transcranial direct current stimulation (tDCS) combined, (2) tPCS alone, (3) tDCS alone, and (4) sham condition. Resting state quantitative electroencephalography (qEEG) and pain assessments were performed before and after each intervention. Results were compared with a cohort of 47 healthy controls. We enrolled six patients with CVP for a total of 21 visits completed. Compared with healthy participants, patients with CVP showed altered cortical activity characterized by increased power in theta, alpha and beta bands, and a significant reduction in the alpha/beta ratio. Regarding tES, the combination of tDCS with tPCS had no effect on power in any of the bandwidths, nor brain regions. Comparing tPCS with tDCS alone, we found that tPCS induced higher increase in power within the theta and alpha bandwidths. This study confirms that patients with CVP present abnormal EEG-indexed cortical activity compared with healthy controls. Moreover, we showed that combining two types of neurostimulation techniques had no effect, whereas the two interventions, when applied individually, have different neural signatures.

Simultaneous transcranial magnetic stimulation and single-neuron recording in alert non-human primates.

Science.gov (United States)

Mueller, Jerel K; Grigsby, Erinn M; Prevosto, Vincent; Petraglia, Frank W; Rao, Hrishikesh; Deng, Zhi-De; Peterchev, Angel V; Sommer, Marc A; Egner, Tobias; Platt, Michael L; Grill, Warren M

2014-08-01

Transcranial magnetic stimulation (TMS) is a widely used, noninvasive method for stimulating nervous tissue, yet its mechanisms of effect are poorly understood. Here we report new methods for studying the influence of TMS on single neurons in the brain of alert non-human primates. We designed a TMS coil that focuses its effect near the tip of a recording electrode and recording electronics that enable direct acquisition of neuronal signals at the site of peak stimulus strength minimally perturbed by stimulation artifact in awake monkeys (Macaca mulatta). We recorded action potentials within ∼1 ms after 0.4-ms TMS pulses and observed changes in activity that differed significantly for active stimulation as compared with sham stimulation. This methodology is compatible with standard equipment in primate laboratories, allowing easy implementation. Application of these tools will facilitate the refinement of next generation TMS devices, experiments and treatment protocols.

Simultaneous transcranial magnetic stimulation and single neuron recording in alert non-human primates

Science.gov (United States)

Mueller, Jerel K.; Grigsby, Erinn M.; Prevosto, Vincent; Petraglia, Frank W.; Rao, Hrishikesh; Deng, Zhi-De; Peterchev, Angel V.; Sommer, Marc A.; Egner, Tobias; Platt, Michael L.; Grill, Warren M.

2014-01-01

Transcranial magnetic stimulation (TMS) is a widely used, noninvasive method for stimulating nervous tissue, yet its mechanisms of effect are poorly understood. Here we report novel methods for studying the influence of TMS on single neurons in the brain of alert non-human primates. We designed a TMS coil that focuses its effect near the tip of a recording electrode and recording electronics that enable direct acquisition of neuronal signals at the site of peak stimulus strength minimally perturbed by stimulation artifact in intact, awake monkeys (Macaca mulatta). We recorded action potentials within ~1 ms after 0.4 ms TMS pulses and observed changes in activity that differed significantly for active stimulation as compared to sham stimulation. The methodology is compatible with standard equipment in primate laboratories, allowing for easy implementation. Application of these new tools will facilitate the refinement of next generation TMS devices, experiments, and treatment protocols. PMID:24974797

Effect of transcranial direct current stimulation on vestibular-ocular and vestibulo-perceptual thresholds.

Science.gov (United States)

Kyriakareli, Artemis; Cousins, Sian; Pettorossi, Vito E; Bronstein, Adolfo M

2013-10-02

Transcranial direct current stimulation (tDCS) was used in 17 normal individuals to modulate vestibulo-ocular reflex (VOR) and self-motion perception rotational thresholds. The electrodes were applied over the temporoparietal junction bilaterally. Both vestibular nystagmic and perceptual thresholds were increased during as well as after tDCS stimulation. Body rotation was labeled as ipsilateral or contralateral to the anode side, but no difference was observed depending on the direction of rotation or hemisphere polarity. Threshold increase during tDCS was greater for VOR than for motion perception. 'Sham' stimulation had no effect on thresholds. We conclude that tDCS produces an immediate and sustained depression of cortical regions controlling VOR and movement perception. Temporoparietal areas appear to be involved in vestibular threshold modulation but the differential effects observed between VOR and perception suggest a partial dissociation between cortical processing of reflexive and perceptual responses.

Transcranial direct current stimulation reduces negative affect but not cigarette craving in overnight abstinent smokers

Directory of Open Access Journals (Sweden)

Jiansong eXu

2013-09-01

Full Text Available Transcranial direct current stimulation (tDCS can enhance cognitive control functions including attention and top-down regulation over negative affect and substance craving in both healthy and clinical populations, including early abstinent (~1.5 h smokers. The aim of this study was to assess whether tDCS modulates negative affect, cigarette craving, and attention of overnight abstinent tobacco dependent smokers. In this study, 24 smokers received a real and a sham session of tDCS after overnight abstinence from smoking on two different days. We applied anode to the left dorsal lateral prefrontal cortex (DLPFC and cathode to the right supra orbital area for 20min with a current of 2.0mA. We used self-report questionnaires Profile of Mood State (POMS to assess negative affect and Urge to Smoke (UTS Scale to assess craving for cigarette smoking, and a computerized visual target identification task to assess attention immediately before and after each tDCS. Smokers reported significantly greater reductions in POMS scores of total mood disturbance and scores of tension-anxiety, depression-dejection, and confusion-bewilderment subscales after real relative to sham tDCS. Furthermore, this reduction in negative affect positively correlated with the level of nicotine dependence as assessed by Fagerström scale. However, reductions in cigarette craving after real vs. sham tDCS did not differ, nor were there differences in reaction time or hit rate change on the visual task. Smokers did not report significant side effects of tDCS. This study demonstrates the safety of tDCS and its promising effect in ameliorating negative affect in overnight abstinent smokers. Its efficacy in treating tobacco dependence deserves further investigation.

High-definition transcranial direct-current stimulation of the right M1 further facilitates left M1 excitability during crossed facilitation.

Science.gov (United States)

Cabibel, Vincent; Muthalib, Makii; Teo, Wei-Peng; Perrey, Stephane

2018-04-01

The crossed-facilitation (CF) effect refers to when motor-evoked potentials (MEPs) evoked in the relaxed muscles of one arm are facilitated by contraction of the opposite arm. The aim of this study was to determine whether high-definition transcranial direct-current stimulation (HD-tDCS) applied to the right primary motor cortex (M1) controlling the left contracting arm [50% maximum voluntary isometric contraction (MVIC)] would further facilitate CF toward the relaxed right arm. Seventeen healthy right-handed subjects participated in an anodal and cathodal or sham HD-tDCS session of the right M1 (2 mA for 20 min) separated by at least 48 h. Single-pulse transcranial magnetic stimulation (TMS) was used to elicit MEPs and cortical silent periods (CSPs) from the left M1 at baseline and 10 min into and after right M1 HD-tDCS. At baseline, compared with resting, CF (i.e., right arm resting, left arm 50% MVIC) increased left M1 MEP amplitudes (+97%) and decreased CSPs (-11%). The main novel finding was that right M1 HD-tDCS further increased left M1 excitability (+28.3%) and inhibition (+21%) from baseline levels during CF of the left M1, with no difference between anodal and cathodal HD-tDCS sessions. No modulation of CSP or MEP was observed during sham HD-tDCS sessions. Our findings suggest that CF of the left M1 combined with right M1 anodal or cathodal HD-tDCS further facilitated interhemispheric interactions during CF from the right M1 (contracting left arm) toward the left M1 (relaxed right arm), with effects on both excitatory and inhibitory processing. NEW & NOTEWORTHY This study shows modulation of the nonstimulated left M1 by right M1 HD-tDCS combined with crossed facilitation, which was probably achieved through modulation of interhemispheric interactions.

Hyper-Transcranial Alternating Current Stimulation: Experimental Manipulation of Inter-Brain Synchrony

Directory of Open Access Journals (Sweden)

Caroline Szymanski

2017-11-01

Full Text Available We walk together, we watch together, we win together: Interpersonally coordinated actions are omnipresent in everyday life, yet the associated neural mechanisms are not well understood. Available evidence suggests that the synchronization of oscillatory activity across brains may provide a mechanism for the temporal alignment of actions between two or more individuals. In an attempt to provide a direct test of this hypothesis, we applied transcranial alternating current stimulation simultaneously to two individuals (hyper-tACS who were asked to drum in synchrony at a set pace. Thirty-eight female-female dyads performed the dyadic drumming in the course of 3 weeks under three different hyper-tACS stimulation conditions: same-phase-same-frequency; different-phase-different-frequency; sham. Based on available evidence and theoretical considerations, stimulation was applied over right frontal and parietal sites in the theta frequency range. We predicted that same-phase-same-frequency stimulation would improve interpersonal action coordination, expressed as the degree of synchrony in dyadic drumming, relative to the other two conditions. Contrary to expectations, both the same-phase-same-frequency and the different-phase-different-frequency conditions were associated with greater dyadic drumming asynchrony relative to the sham condition. No influence of hyper-tACS on behavioral performance was seen when participants were asked to drum separately in synchrony to a metronome. Individual and dyad preferred drumming tempo was also unaffected by hyper-tACS. We discuss limitations of the present version of the hyper-tACS paradigm, and suggest avenues for future research.

Hyper-Transcranial Alternating Current Stimulation: Experimental Manipulation of Inter-Brain Synchrony.

Science.gov (United States)

Szymanski, Caroline; Müller, Viktor; Brick, Timothy R; von Oertzen, Timo; Lindenberger, Ulman

2017-01-01

We walk together, we watch together, we win together: Interpersonally coordinated actions are omnipresent in everyday life, yet the associated neural mechanisms are not well understood. Available evidence suggests that the synchronization of oscillatory activity across brains may provide a mechanism for the temporal alignment of actions between two or more individuals. In an attempt to provide a direct test of this hypothesis, we applied transcranial alternating current stimulation simultaneously to two individuals (hyper-tACS) who were asked to drum in synchrony at a set pace. Thirty-eight female-female dyads performed the dyadic drumming in the course of 3 weeks under three different hyper-tACS stimulation conditions: same-phase-same-frequency; different-phase-different-frequency; sham. Based on available evidence and theoretical considerations, stimulation was applied over right frontal and parietal sites in the theta frequency range. We predicted that same-phase-same-frequency stimulation would improve interpersonal action coordination, expressed as the degree of synchrony in dyadic drumming, relative to the other two conditions. Contrary to expectations, both the same-phase-same-frequency and the different-phase-different-frequency conditions were associated with greater dyadic drumming asynchrony relative to the sham condition. No influence of hyper-tACS on behavioral performance was seen when participants were asked to drum separately in synchrony to a metronome. Individual and dyad preferred drumming tempo was also unaffected by hyper-tACS. We discuss limitations of the present version of the hyper-tACS paradigm, and suggest avenues for future research.

Intermittent theta-burst transcranial magnetic stimulation for treatment of Parkinson disease.

Science.gov (United States)

Benninger, D H; Berman, B D; Houdayer, E; Pal, N; Luckenbaugh, D A; Schneider, L; Miranda, S; Hallett, M

2011-02-15

To investigate the safety and efficacy of intermittent theta-burst stimulation (iTBS) in the treatment of motor symptoms in Parkinson disease (PD). Progression of PD is characterized by the emergence of motor deficits, which eventually respond less to dopaminergic therapy and pose a therapeutic challenge. Repetitive transcranial magnetic stimulation (rTMS) has shown promising results in improving gait, a major cause of disability, and may provide a therapeutic alternative. iTBS is a novel type of rTMS that may be more efficacious than conventional rTMS. In this randomized, double-blind, sham-controlled study, we investigated safety and efficacy of iTBS of the motor and dorsolateral prefrontal cortices in 8 sessions over 2 weeks (evidence Class I). Assessment of safety and clinical efficacy over a 1-month period included timed tests of gait and bradykinesia, Unified Parkinson's Disease Rating Scale (UPDRS), and additional clinical, neuropsychological, and neurophysiologic measures. We investigated 26 patients with mild to moderate PD: 13 received iTBS and 13 sham stimulation. We found beneficial effects of iTBS on mood, but no improvement of gait, bradykinesia, UPDRS, and other measures. EEG/EMG monitoring recorded no pathologic increase of cortical excitability or epileptic activity. Few reported discomfort or pain and one experienced tinnitus during real stimulation. iTBS of the motor and prefrontal cortices appears safe and improves mood, but failed to improve motor performance and functional status in PD. This study provides Class I evidence that iTBS was not effective for gait, upper extremity bradykinesia, or other motor symptoms in PD.

Shaping pseudoneglect with transcranial cerebellar direct current stimulation and music listening

Directory of Open Access Journals (Sweden)

Silvia ePicazio

2015-03-01

Full Text Available Non-invasive brain stimulation modulates cortical excitability depending on the initial activation state of the structure being stimulated. Combination of cognitive with neurophysiological stimulations has been successfully employed to modulate responses of specific brain regions. The present research combined a neurophysiological pre-conditioning with a cognitive conditioning stimulation to modulate behavior. We applied this new state-dependency approach to investigate the cerebellar role in musical and spatial information processing, given that a link between musical perception and visuo-spatial abilities and a clear cerebellar involvement in music perception and visuo-spatial tasks have been reported. Cathodal, anodal or sham transcranial cerebellar Direct Current Stimulation (tcDCS pre-conditioning was applied on the left cerebellar hemisphere followed by conditioning stimulation through music or white noise listening in a sample of healthy subjects performing a Line Bisection Task (LBT. The combination of the cathodal stimulation with music listening resulted in a marked attentional shift toward the right hemispace, compensating thus the natural leftward bias of the baseline condition (pseudoneglect. Conversely, the anodal or sham pre-conditioning stimulations combined with either music and white noise conditioning listening did not modulate spatial attention. The efficacy of the combined stimulation (cathodal pre-conditioning and music conditioning and the absence of any effect of the single stimulations provide a strong support to the state-dependency theory. They propose that tcDCS in combination with music listening could act as a rehabilitative tool to improve cognitive functions in the presence of neglect or other spatial disorders.

Plasma catecholamine and serum gastrin concentrations during sham feeding

DEFF Research Database (Denmark)

Bekker, Carsten; Andersen, D; Kronborg, O

1983-01-01

Plasma adrenaline, plasma noradrenaline and serum gastrin concentrations were measured before and after sham feeding in eight patients with duodenal ulcer and in four normal subjects. No significant change in the concentrations was observed after sham feeding. In three patients with duodenal ulce...... groups. It is concluded that sympathetic nervous activity and serum gastrin concentrations are not influenced by sham feeding in contrast to the influence of insulin hypoglycemia....... an insulin test resulted in a 25-fold rise in plasma adrenaline. The ulcer patients showed significantly higher levels of plasma adrenaline and plasma noradrenaline than the normal subjects both before and after sham feeding, and this difference was probably not caused only by age difference in the two...

Dopamine release in human striatum induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex

Energy Technology Data Exchange (ETDEWEB)

Cho, Sang Soo; Yoon, Eun Jin; Kim, Yu Kyeong; Lee, Won Woo; Kim, Sang Eun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

2005-07-01

Animal study suggests that prefrontal cortex plays an important Animal studies suggest that prefrontal cortex plays an important role in the modulation of dopamine (DA) release in subcortical areas. However, little is known about the relationship between DA release and prefrontal activation in human. We investigated whether repetitive transcranial magnetic stimulation (rTMS) over left dorsolateral prefrontal cortex (DLPFC) influences DA release in human striatum with SPECT measurements of striatal binding of [123I)iodobenzamide (IBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy male volunteers (age, 25{+-}2 yr) were studied with brain [123I]IBZM SPECT under three conditions (resting, Sham stimulation, and active rTMS over left DLPFC), while receiving a bolus plus constant infusion of [123I]IBZM DLPFC was defined as a 6 cm anterior and 1cm lateral from the primary motor cortex. rTMS session consisted of three blocks, in each block, 15 trains of 2 see duration were delivered with 10 Hz stimulation frequency, 100% motor threshold, and between-train intervals of 10 sec. Striatal V3', calculated as (striatal - occipital) / occipital activity ratio, was measured under equilibrium condition, at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over DLPFC induced reduction of V3' in the ipsilateral and contralateral striatum by 9.7% {+-} 1.3% and 10.6% {+-} 3.2%, respectively, compared with sham procedures (P < 0.01 and P < 0.01, respectively), indicating striatal DA release elicited by rTMS over DLPFC. V3' reduction in the ipsilateral caudate nucleus was greater than that in the contralateral caudate nucleus (9.9% {+-} 4.5% vs. 6.6% {+-} 3.1%, P < 0.05). These data demonstrate DA release in human striatum induced by rTMS over DLPFC, supporting that cortico-striatal fibers originating in prefrontal cortex are involved in local DA release.

Dopamine release in human striatum induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex

International Nuclear Information System (INIS)

Cho, Sang Soo; Yoon, Eun Jin; Kim, Yu Kyeong; Lee, Won Woo; Kim, Sang Eun

2005-01-01

Animal study suggests that prefrontal cortex plays an important Animal studies suggest that prefrontal cortex plays an important role in the modulation of dopamine (DA) release in subcortical areas. However, little is known about the relationship between DA release and prefrontal activation in human. We investigated whether repetitive transcranial magnetic stimulation (rTMS) over left dorsolateral prefrontal cortex (DLPFC) influences DA release in human striatum with SPECT measurements of striatal binding of [123I)iodobenzamide (IBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy male volunteers (age, 25±2 yr) were studied with brain [123I]IBZM SPECT under three conditions (resting, Sham stimulation, and active rTMS over left DLPFC), while receiving a bolus plus constant infusion of [123I]IBZM DLPFC was defined as a 6 cm anterior and 1cm lateral from the primary motor cortex. rTMS session consisted of three blocks, in each block, 15 trains of 2 see duration were delivered with 10 Hz stimulation frequency, 100% motor threshold, and between-train intervals of 10 sec. Striatal V3', calculated as (striatal - occipital) / occipital activity ratio, was measured under equilibrium condition, at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over DLPFC induced reduction of V3' in the ipsilateral and contralateral striatum by 9.7% ± 1.3% and 10.6% ± 3.2%, respectively, compared with sham procedures (P < 0.01 and P < 0.01, respectively), indicating striatal DA release elicited by rTMS over DLPFC. V3' reduction in the ipsilateral caudate nucleus was greater than that in the contralateral caudate nucleus (9.9% ± 4.5% vs. 6.6% ± 3.1%, P < 0.05). These data demonstrate DA release in human striatum induced by rTMS over DLPFC, supporting that cortico-striatal fibers originating in prefrontal cortex are involved in local DA release

Synergistic effect of combined transcranial direct current stimulation/constraint-induced movement therapy in children and young adults with hemiparesis: study protocol.

Science.gov (United States)

Gillick, Bernadette; Menk, Jeremiah; Mueller, Bryon; Meekins, Gregg; Krach, Linda E; Feyma, Timothy; Rudser, Kyle

2015-11-12

Perinatal stroke occurs in more than 1 in 2,500 live births and resultant congenital hemiparesis necessitates investigation into interventions which may improve long-term function and decreased burden of care beyond current therapies ( http://www.cdc.gov/ncbddd/cp/data.html ). Constraint-Induced Movement Therapy (CIMT) is recognized as an effective hemiparesis rehabilitation intervention. Transcranial direct current stimulation as an adjunct treatment to CIMT may potentiate neuroplastic responses and improve motor function. The methodology of a clinical trial in children designed as a placebo-controlled, serial -session, non-invasive brain stimulation trial incorporating CIMT is described here. The primary hypotheses are 1) that no serious adverse events will occur in children receiving non-invasive brain stimulation and 2) that children in the stimulation intervention group will show significant improvements in hand motor function compared to children in the placebo stimulation control group. A randomized, controlled, double-blinded clinical trial. Twenty children and/or young adults (ages 8-21) with congenital hemiparesis, will be enrolled. The intervention group will receive ten 2-hour sessions of transcranial direct current stimulation combined with constraint-induced movement therapy and the control group will receive sham stimulation with CIMT. The primary outcome measure is safety assessment of transcranial direct current stimulation by physician evaluation, vital sign monitoring and symptom reports. Additionally, hand function will be evaluated using the Assisting Hand Assessment, grip strength and assessment of goals using the Canadian Occupational Performance Measure. Neuroimaging will confirm diagnoses, corticospinal tract integrity and cortical activation. Motor cortical excitability will also be examined using transcranial magnetic stimulation techniques. Combining non-invasive brain stimulation and CIMT interventions has the potential to improve motor

Transcranial Alternating Current Stimulation Attenuates Neuronal Adaptation.

Science.gov (United States)

Kar, Kohitij; Duijnhouwer, Jacob; Krekelberg, Bart

2017-03-01

We previously showed that brief application of 2 mA (peak-to-peak) transcranial currents alternating at 10 Hz significantly reduces motion adaptation in humans. This is but one of many behavioral studies showing that weak currents applied to the scalp modulate neural processing. Transcranial stimulation has been shown to improve perception, learning, and a range of clinical symptoms. Few studies, however, have measured the neural consequences of transcranial current stimulation. We capitalized on the strong link between motion perception and neural activity in the middle temporal (MT) area of the macaque monkey to study the neural mechanisms that underlie the behavioral consequences of transcranial alternating current stimulation. First, we observed that 2 mA currents generated substantial intracranial fields, which were much stronger in the stimulated hemisphere (0.12 V/m) than on the opposite side of the brain (0.03 V/m). Second, we found that brief application of transcranial alternating current stimulation at 10 Hz reduced spike-frequency adaptation of MT neurons and led to a broadband increase in the power spectrum of local field potentials. Together, these findings provide a direct demonstration that weak electric fields applied to the scalp significantly affect neural processing in the primate brain and that this includes a hitherto unknown mechanism that attenuates sensory adaptation. SIGNIFICANCE STATEMENT Transcranial stimulation has been claimed to improve perception, learning, and a range of clinical symptoms. Little is known, however, how transcranial current stimulation generates such effects, and the search for better stimulation protocols proceeds largely by trial and error. We investigated, for the first time, the neural consequences of stimulation in the monkey brain. We found that even brief application of alternating current stimulation reduced the effects of adaptation on single-neuron firing rates and local field potentials; this mechanistic

Dual-hemisphere transcranial direct current stimulation over primary motor cortex enhances consolidation of a ballistic thumb movement.

Science.gov (United States)

Koyama, Soichiro; Tanaka, Satoshi; Tanabe, Shigeo; Sadato, Norihiro

2015-02-19

Transcranial direct current stimulation (tDCS) is a noninvasive technique that modulates motor performance and learning. Previous studies have shown that tDCS over the primary motor cortex (M1) can facilitate consolidation of various motor skills. However, the effect of tDCS on consolidation of newly learned ballistic movements remains unknown. The present study tested the hypothesis that tDCS over M1 enhances consolidation of ballistic thumb movements in healthy adults. Twenty-eight healthy subjects participated in an experiment with a single-blind, sham-controlled, between-group design. Fourteen subjects practiced a ballistic movement with their left thumb during dual-hemisphere tDCS. Subjects received 1mA anodal tDCS over the contralateral M1 and 1mA cathodal tDCS over the ipsilateral M1 for 25min during the training session. The remaining 14 subjects underwent identical training sessions, except that dual-hemisphere tDCS was applied for only the first 15s (sham group). All subjects performed the task again at 1h and 24h later. Primary measurements examined improvement in peak acceleration of the ballistic thumb movement at 1h and 24h after stimulation. Improved peak acceleration was significantly greater in the tDCS group (144.2±15.1%) than in the sham group (98.7±9.1%) (Pballistic thumb movement in healthy adults. Dual-hemisphere tDCS over M1 may be useful to improve elemental motor behaviors, such as ballistic movements, in patients with subcortical strokes. Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

The Effects of Transcranial Direct Current Stimulation (tDCS on Psychomotor and Visual Perception Functions Related to Driving Skills

Directory of Open Access Journals (Sweden)

Alexander Brunnauer

2018-01-01

Full Text Available Objective: It could be demonstrated that anodal transcranial direct current stimulation (tDCS of the left dorsolateral prefrontal cortex (DLPFC enhances accuracy in working memory tasks and reaction time in healthy adults and thus may also have an influence on complex everyday tasks like driving a car. However, no studies have applied tDCS to psychomotor skills related to a standard driving test so far.Methods: 10 female and 5 male healthy adults without any medication and history of psychiatric or neurological illness were randomly assigned to two groups receiving active and sham stimulation in a double blind, cross-over study design. Standardized computerized psychomotor tests according to the German guidelines for road and traffic safety were administered at baseline. Then they performed the same tests during an anodal or sham tDCS of the left DLPFC in two separated sessions.Results: No significant improvements in skills related to driving performance like visual perception, stress tolerance, concentration, and vigilance could be shown after left anodal prefrontal tDCS. Side effects were low and did not differ between active and sham stimulation.Conclusions: The findings of our study indicate that left prefrontal tDCS may not alter driving skills affording more automated action patterns but as shown in previous studies may have an influence on driving behavior requiring executive control processes. This however has to be proved in future studies and within greater samples.

High-brightness switchable multiwavelength remote laser in air

Energy Technology Data Exchange (ETDEWEB)

Yao Jinping; Cheng Ya; Xu Zhizhan [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Zeng Bin; Li Guihua; Chu Wei; Ni Jielei; Zhang Haisu [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of Chinese Academy of Sciences, Beijing 100080 (China); Xu Huailiang [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Chin, See Leang [Center for Optics, Universite Laval, Quebec City, Quebec G1V 0A6 (Canada)

2011-11-15

We demonstrate a harmonic-seeded switchable multiwavelength laser in air driven by intense midinfrared femtosecond laser pulses, in which population inversion occurs at an ultrafast time scale (i.e., less than {approx}200 fs) owing to direct formation of excited molecular nitrogen ions by strong-field ionization of inner-valence electrons. The bright multiwavelength laser in air opens the perspective for remote detection of multiple pollutants based on nonlinear optical spectroscopy.

Salicylhydroxamic acid (SHAM) inhibition of the DIC-pump in unicellular algae

International Nuclear Information System (INIS)

Goyal, A.; Tolbert, N.E.

1989-01-01

SHAM at 1 or 2 mM inhibits dissolved inorganic carbon (DIC) concentrating mechanisms in unicellular green algae as measured by photosynthetic oxygen evolution or by 14 C-inorganic carbon uptake (using silicone oil centrifugation techniques). This inhibition was reversed by high levels of DIC whereby the cells do not require the concentrating mechanism. SHAM inhibited the DIC-pump, which uses external CO 2 , in three species of algae, Dunaliella tertiolecta, Chlamydomonas reinhardtii, and Scenedesmus obliquus when adapted to low CO 2 and assayed around neutral pH. Scenedesmus adapted to air at pH 9.0 to use external HCO 3 - were not affected by SHAM. It is important to establish low optimum concentrations of SHAM, which varied with the algal species. The mechanism of SHAM inhibition of the CO 2 concentrating process is unknown. SHAM inhibits alternative respiration in these algae, but SHAM may also inhibit other reactions involving H + gradients or transporters associated with the DIC-pump

Polarity-Specific Transcranial Direct Current Stimulation Disrupts Auditory Pitch Learning

Directory of Open Access Journals (Sweden)

Reiko eMatsushita

2015-05-01

Full Text Available Transcranial direct current stimulation (tDCS is attracting increasing interest because of its potential for therapeutic use. While its effects have been investigated mainly with motor and visual tasks, less is known in the auditory domain. Past tDCS studies with auditory tasks demonstrated various behavioural outcomes, possibly due to differences in stimulation parameters or task measurements used in each study. Further research using well-validated tasks are therefore required for clarification of behavioural effects of tDCS on the auditory system. Here, we took advantage of findings from a prior functional magnetic resonance imaging study, which demonstrated that the right auditory cortex is modulated during fine-grained pitch learning of microtonal melodic patterns. Targeting the right auditory cortex with tDCS using this same task thus allowed us to test the hypothesis that this region is causally involved in pitch learning. Participants in the current study were trained for three days while we measured pitch discrimination thresholds using microtonal melodies on each day using a psychophysical staircase procedure. We administered anodal, cathodal, or sham tDCS to three groups of participants over the right auditory cortex on the second day of training during performance of the task. Both the sham and the cathodal groups showed the expected significant learning effect (decreased pitch threshold over the three days of training; in contrast we observed a blocking effect of anodal tDCS on auditory pitch learning, such that this group showed no significant change in thresholds over the three days. The results support a causal role for the right auditory cortex in pitch discrimination learning.

Effect of transcranial direct current stimulation (tDCS) over the prefrontal cortex combined with cognitive training for treating schizophrenia: a sham-controlled randomized clinical trial

OpenAIRE

Shiozawa, Pedro; Gomes, July Silveira; Ducos, Daniella Valverde; Akiba, Henrique Teruo; Dias, Álvaro Machado; Trevizol, Alisson Paulino; Uchida, Ricardo R.; Orlov, Natasza; Cordeiro, Quirino

2016-01-01

Abstract Introduction: We report a transcranial direct current stimulation (tDCS) protocol over the dorsolateral prefrontal cortex (DLPFC) combined with cognitive training in schizophrenia. Method: We assessed psychotic symptoms in nine patients using the Positive and Negative Syndrome Scale (PANSS). All evaluations were scored at baseline, at the end of the intervention protocol, and during a 4-week follow-up. The tDCS protocol consisted of 10 consecutive sessions over 5-day periods. We pl...

Influence of Concurrent Finger Movements on Transcranial Direct Current Stimulation (tDCS)-Induced Aftereffects.

Science.gov (United States)

Shirota, Yuichiro; Terney, Daniella; Antal, Andrea; Paulus, Walter

2017-01-01

Transcranial direct current stimulation (tDCS) has been reported to have bidirectional influence on the amplitude of motor-evoked potentials (MEPs) in resting participants in a polarity-specific manner: anodal tDCS increased and cathodal tDCS decreased them. More recently, the effects of tDCS have been shown to depend on a number of additional factors. We investigated whether a small variety of movements involving target and non-target muscles could differentially modify the efficacy of tDCS. MEPs were elicited from the right first dorsal interosseous muscle, defined as the target muscle, by single pulse transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). During M1 tDCS, which lasted for 10 min applying anodal, cathodal, or sham condition, the participants were instructed to squeeze a ball with their right hand (Task 1), to move their right index finger only in the medial (Task 2), in the lateral direction (Task 3), or in medial and lateral direction alternatively (Task 4). Anodal tDCS reduced MEP amplitudes measured in Task 1 and Task 2, but to a lesser extent in the latter. In Task 3, anodal tDCS led to greater MEP amplitudes than cathodal stimulation. Alternating movements resulted in no effect of tDCS on MEP amplitude (Task 4). The results are congruent with the current notion that the aftereffects of tDCS are highly variable relying on a number of factors including the type of movements executed during stimulation.

Fast switchable ferroelectric liquid crystal gratings with two electro-optical modes

International Nuclear Information System (INIS)

Ma, Ying; Srivastava, A. K.; Chigrinov, V. G.; Kwok, H.-S.; Wang, Xiaoqian

2016-01-01

In this article, we reveal a theoretical and experimental illustration of the Ferroelectric liquid crystal (FLC) grating fabricated by mean of patterned alignment based on photo-alignment. The complexity related to the mismatching of the predefined alignment domains on the top and bottom substrate has been avoided by incorporating only one side photo aligned substrate while the other substrate does not have any alignment layer. Depending on the easy axis in the said alignment domains and the azimuth plane of the impinging polarized light, the diffracting element can be tuned in two modes i.e. DIFF/OFF switchable and DIFF/TRANS switchable modes, which can be applied to different applications. The diffraction profile has been illustrated theoretically that fits well with the experimental finding and thus the proposed diffraction elements with fast response time and high diffraction efficiency could find application in many modern devices.

Variational method for inverting the Kohn-Sham procedure

International Nuclear Information System (INIS)

Kadantsev, Eugene S.; Stott, M.J.

2004-01-01

A procedure based on a variational principle is developed for determining the local Kohn-Sham (KS) potential corresponding to a given ground-state electron density. This procedure is applied to calculate the exchange-correlation part of the effective Kohn-Sham (KS) potential for the neon atom and the methane molecule

What is the optimal anodal electrode position for inducing corticomotor excitability changes in transcranial direct current stimulation?

Science.gov (United States)

Lee, Minji; Kim, Yun-Hee; Im, Chang-Hwan; Kim, Jung-Hoon; Park, Chang-hyun; Chang, Won Hyuk; Lee, Ahee

2015-01-01

Transcranial direct current stimulation (tDCS) non-invasively modulates brain function by inducing neuronal excitability. The conventional hot spot for inducing the highest current density in the hand motor area may not be the optimal site for effective stimulation. In this study, we investigated the influence of the center position of the anodal electrode on changes in motor cortical excitability. We considered three tDCS conditions in 16 healthy subjects: (i) real stimulation with the anodal electrode located at the conventional hand motor hot spot determined by motor evoked potentials (MEPs); (ii) real stimulation with the anodal electrode located at the point with the highest current density in the hand motor area as determined by electric current simulation; and (iii) sham stimulation. Motor cortical excitability as measured by MEP amplitude increased after both real stimulation conditions, but not after sham stimulation. Stimulation using the simulation-derived anodal electrode position, which was found to be posterior to the MEP hot spot for all subjects, induced higher motor cortical excitability. Individual positioning of the anodal electrode, based on the consideration of anatomical differences between subjects, appears to be important for maximizing the effects of tDCS. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The Modulation of Error Processing in the Medial Frontal Cortex by Transcranial Direct Current Stimulation

Directory of Open Access Journals (Sweden)

Lisa Bellaïche

2013-01-01

Full Text Available Background. In order to prevent future errors, we constantly control our behavior for discrepancies between the expected (i.e., intended and the real action outcome and continuously adjust our behavior accordingly. Neurophysiological correlates of this action-monitoring process can be studied with event-related potentials (error-related negativity (ERN and error positivity (Pe originating from the medial prefrontal cortex (mPFC. Patients with neuropsychiatric diseases often show performance monitoring dysfunctions potentially caused by pathological changes of cortical excitability; therefore, a modulation of the underlying neuronal activity might be a valuable therapeutic tool. One technique which allows us to explore cortical modulation of neural networks is transcranial direct current stimulation (tDCS. Therefore, we tested the effect of medial-prefrontal tDCS on error-monitoring potentials in 48 healthy subjects randomly assigned to anodal, cathodal, or sham stimulation. Results. We found that cathodal stimulation attenuated Pe amplitudes compared to both anodal and sham stimulation, but no effect for the ERN. Conclusions. Our results indicate that cathodal tDCS over the mPFC results in an attenuated cortical excitability leading to decreased Pe amplitudes. We therefore conclude that tDCS has a neuromodulatory effect on error-monitoring systems suggesting a future approach to modify the sensitivity of corresponding neural networks in patients with action-monitoring deficits.

Transcranial Direct Current Stimulation to Enhance Dual-Task Gait Training in Parkinson's Disease: A Pilot RCT.

Science.gov (United States)

Schabrun, Siobhan M; Lamont, Robyn M; Brauer, Sandra G

2016-01-01

To investigate the feasibility and safety of a combined anodal transcranial direct current stimulation (tDCS) and dual task gait training intervention in people with Parkinson's Disease (PD) and to provide data to support a sample size calculation for a fully powered trial should trends of effectiveness be present. A pilot, randomized, double-blind, sham-controlled parallel group trial with 12 week follow-up. A university physiotherapy department. Sixteen participants diagnosed with PD received nine dual task gait training sessions over 3 weeks. Participants were randomized to receive either active or sham tDCS applied for the first 20 minutes of each session. The primary outcome was gait speed while undertaking concurrent cognitive tasks (word lists, counting, conversation). Secondary measures included step length, cadence, Timed Up and Go, bradykinesia and motor speed. Gait speed, step length and cadence improved in both groups, under all dual task conditions. This effect was maintained at follow-up. There was no difference between the active and sham tDCS groups. Time taken to perform the TUGwords also improved, with no difference between groups. The active tDCS group did however increase their correct cognitive response rate during the TUGwords and TUGcount. Bradykinesia improved after training in both groups. Three weeks of dual task gait training resulted in improved gait under dual task conditions, and bradykinesia, immediately following training and at 12 weeks follow-up. The only parameter enhanced by tDCS was the number of correct responses while performing the dual task TUG. tDCS applied to M1 may not be an effective adjunct to dual task gait training in PD. Australia-New Zealand Clinical Trials Registry ACTRN12613001093774.

Transcranial alternating current stimulation (tACS increases risk taking behavior in the Balloon Analogue Risk Task

Directory of Open Access Journals (Sweden)

Tal eSela

2012-02-01

Full Text Available The process of evaluating risks and benefits involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC. It has been proposed that in conflict and reward situations, theta-band (4–8 Hz oscillatory activity in the frontal cortex may reflect an electrophysiological mechanism for coordinating neural networks monitoring behavior, as well as facilitating task-specific adaptive changes. The goal of the present study was to investigate the hypothesis that theta-band oscillatory balance between right and left frontal and prefrontal regions, with a predominance role to the right hemisphere, is crucial for regulatory control during decision-making under risk. In order to explore this hypothesis, we used transcranial Alternating Current Stimulation (tACS, a novel technique that provides the opportunity to explore the functional role of neuronal oscillatory activities and to establish a causal link between specific oscillations and functional lateralization in risky decision-making situations. For this aim, healthy participants were randomly allocated to one of three stimulation groups (LH stimulation / RH stimulation / Sham stimulation, with active AC stimulation delivered in a frequency-dependent manner (at 6.5 Hz; 1mA peak to-peak. During the AC stimulation, participants performed the Balloon Analog Risk Task. This experiment revealed that participants receiving LH stimulation displayed riskier decision-making style compared to sham and RH stimulation groups. However, there was no difference in decision-making behaviors between sham and RH stimulation groups. The current study extends the notion that DLPFC activity is critical for adaptive decision-making in the context of risk-taking and emphasis the role of theta-band oscillatory activity during risky decision-making situations.

Effects of transcranial direct current stimulation (tDCS) on multiscale complexity of dual-task postural control in older adults.

Science.gov (United States)

Zhou, Diange; Zhou, Junhong; Chen, Hu; Manor, Brad; Lin, Jianhao; Zhang, Jue

2015-08-01

Transcranial direct current stimulation (tDCS) targeting the prefrontal cortex reduces the size and speed of standing postural sway in younger adults, particularly when performing a cognitive dual task. Here, we hypothesized that tDCS would alter the complex dynamics of postural sway as quantified by multiscale entropy (MSE). Twenty healthy older adults completed two study visits. Center-of-pressure (COP) fluctuations were recorded during single-task (i.e., quiet standing) and dual-task (i.e., standing while performing serial subtractions) conditions, both before and after a 20-min session of real or sham tDCS. MSE was used to estimate COP complexity within each condition. The percentage change in complexity from single- to dual-task conditions (i.e., dual-task cost) was also calculated. Before tDCS, COP complexity was lower (p = 0.04) in the dual-task condition as compared to the single-task condition. Neither real nor sham tDCS altered complexity in the single-task condition. As compared to sham tDCS, real tDCS increased complexity in the dual-task condition (p = 0.02) and induced a trend toward improved serial subtraction performance (p = 0.09). Moreover, those subjects with lower dual-task COP complexity at baseline exhibited greater percentage increases in complexity following real tDCS (R = -0.39, p = 0.05). Real tDCS also reduced the dual-task cost to complexity (p = 0.02), while sham stimulation had no effect. A single session of tDCS targeting the prefrontal cortex increased standing postural sway complexity with concurrent non-postural cognitive task. This form of noninvasive brain stimulation may be a safe strategy to acutely improve postural control by enhancing the system's capacity to adapt to stressors.

Single-Session Transcranial Direct Current Stimulation Temporarily Improves Symptoms, Mood, and Self-Regulatory Control in Bulimia Nervosa: A Randomised Controlled Trial.

Science.gov (United States)

Kekic, Maria; McClelland, Jessica; Bartholdy, Savani; Boysen, Elena; Musiat, Peter; Dalton, Bethan; Tiza, Meyzi; David, Anthony S; Campbell, Iain C; Schmidt, Ulrike

2017-01-01

Evidence suggests that pathological eating behaviours in bulimia nervosa (BN) are underpinned by alterations in reward processing and self-regulatory control, and by functional changes in neurocircuitry encompassing the dorsolateral prefrontal cortex (DLPFC). Manipulation of this region with transcranial direct current stimulation (tDCS) may therefore alleviate symptoms of the disorder. This double-blind sham-controlled proof-of-principle trial investigated the effects of bilateral tDCS over the DLPFC in adults with BN. Thirty-nine participants (two males) received three sessions of tDCS in a randomised and counterbalanced order: anode right/cathode left (AR/CL), anode left/cathode right (AL/CR), and sham. A battery of psychological/neurocognitive measures was completed before and after each session and the frequency of bulimic behaviours during the following 24-hours was recorded. AR/CL tDCS reduced eating disorder cognitions (indexed by the Mizes Eating Disorder Cognitions Questionnaire-Revised) when compared to AL/CR and sham tDCS. Both active conditions suppressed the self-reported urge to binge-eat and increased self-regulatory control during a temporal discounting task. Compared to sham stimulation, mood (assessed with the Profile of Mood States) improved after AR/CL but not AL/CR tDCS. Lastly, the three tDCS sessions had comparable effects on the wanting/liking of food and on bulimic behaviours during the 24 hours post-stimulation. These data suggest that single-session tDCS transiently improves symptoms of BN. They also help to elucidate possible mechanisms of action and highlight the importance of selecting the optimal electrode montage. Multi-session trials are needed to determine whether tDCS has potential for development as a treatment for adult BN.

Repetitive deep transcranial magnetic stimulation improves verbal fluency and written language in a patient with primary progressive aphasia-logopenic variant (LPPA).

Science.gov (United States)

Trebbastoni, Alessandro; Raccah, Ruggero; de Lena, Carlo; Zangen, Abraham; Inghilleri, Maurizio

2013-07-01

To date, no therapies are available for the logopenic variant of primary progressive aphasia (LPPA). Even though deep repetitive transcranial magnetic stimulation (rTMS) may improve cognitive functions in some neurodegenerative disorders, no previous studies investigated its effects in patients with LPPA. Our aim was to investigate the effects on cognitive function of high frequency rTMS (hf-rTMS) delivered over the left dorso-lateral prefrontal cortex (DLPFC) through a coil designed for deep rTMS, compared to a SHAM stimulation, in a right-handed patient with LPPA. The patient presented a progressive language impairment (phonological errors in speech and naming, impaired single word retrieval and sentences repetition) and predominant left perisylvian atrophy and hypoperfusion. He received four stimulation cycles (two REAL and two SHAM) each of whom lasted 20 min for 5 consecutive days. Patient's performances in frontal, visuo-spatial and linguistic tasks were evaluated before and after each stimulation session. Test scores after REAL were compared with those obtained at baseline and after SHAM. We found a temporary and highly significant improvement in the linguistic skills (both oral and written tasks) but not in the other cognitive domains tested, after REAL, but not SHAM stimulations. Hf-rTMS delivered over the DLPFC could improve language in LPPA by enhancing long-term potentiation and synaptic plasticity within the stimulated and interconnected areas involved in language network. Our findings might prompt future researches into the feasibility and efficacy of deep hf-rTMS as a therapeutic tool in progressive aphasia syndromes and other neurodegenerative disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

A comparison of the effects of transcranial direct current stimulation and caffeine on vigilance and cognitive performance during extended wakefulness.

Science.gov (United States)

McIntire, Lindsey K; McKinley, R Andy; Goodyear, Chuck; Nelson, Justin

2014-01-01

Sleep deprivation from extended duty hours is a common complaint for many occupations. Caffeine is one of the most common countermeasures used to combat fatigue. However, the benefits of caffeine decline over time and with chronic use. Our objective was to evaluate the efficacy of anodal transcranial direct current stimulation (tDCS) applied to the pre-frontal cortex at 2 mA for 30 min to remediate the effects of sleep deprivation and to compare the behavioral effects of tDCS with those of caffeine. Three groups of 10 participants each received either active tDCS with placebo gum, caffeine gum with sham tDCS, or sham tDCS with placebo gum during 30 h of extended wakefulness. Our results show that tDCS prevented a decrement in vigilance and led to better subjective ratings for fatigue, drowsiness, energy, and composite mood compared to caffeine and control in sleep-deprived individuals. Both the tDCS and caffeine produced similar improvements in latencies on a short-term memory task and faster reaction times in a psychomotor task when compared to the placebo group. Interestingly, changes in accuracy for the tDCS group were not correlated to changes in mood; whereas, there was a relationship for the caffeine and sham groups. Our data suggest that tDCS could be a useful fatigue countermeasure and may be more beneficial than caffeine since boosts in performance and mood last several hours. Published by Elsevier Inc.

Striatal dopamine release induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex: effect of aging

International Nuclear Information System (INIS)

Bang, Seong Ae; Cho, Sang Soo; Yoon, Eun Jin; Kim, Ji Sun; Lee, Byung Chul; Kim, Yu Kyeong; Kim, Sang Eun

2007-01-01

We previously demonstrated dopamine (DA) release in the bilateral striatal regions following prefrontal repetitive transcranial magnetic stimulation (rTMS) in young subjects. Several lines of evidence support substantial age-related changes in human dopaminergic neurotransmission. One possible explanation is alteration of cortico striatal neural connection with aging. Therefore, we investigated how frontal activation by rTMS influences striatal DA release in the elderly with SPECT measurements of striatal binding of [123I]iodobenzamide (lBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy elderly male subjects (age, 64 3 y) were studied with brain [123I]IBZM SPECT under three conditions (resting, sham stimulation, and active rTMS over left dorsolateral prefrontal cortex (DLPFC)), while receiving a bolus plus constant infusion of [123I]IBZM. rTMS session consisted of three blocks. In each block, 15 trains of 2 sec duration were delivered with 10 Hz stimulation frequency and 100% motor threshold. Striatal V3', calculated as (striatal - occipital)/occipital radioactivity, was measured under equilibrium condition at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over left DLPFC induced no significant change in V3' in the right striatum compared with baseline condition (0.91 0.25 vs. 0.96 0.25, P = NS). Interestingly, left striatal V3' showed a significant increase after rTMS over left DLPFC compared with sham condition (1.09 0.33 vs. 0.93 0.27, P < 0.05; 17.0 11.1% increase). These results are discrepant from previous ones from young subjects, who showed frontal rTMS-induced reduction of striatal V3', indicating rTMS-induced striatal DA release. We found no significant striatal DA release induced by rTMS over DLPFC in healthy elderly subjects using in vivo binding competition techniques. These results may support an altered cortico striatal circuit in normal aging

Striatal dopamine release induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex: effect of aging

Energy Technology Data Exchange (ETDEWEB)

Bang, Seong Ae; Cho, Sang Soo; Yoon, Eun Jin; Kim, Ji Sun; Lee, Byung Chul; Kim, Yu Kyeong; Kim, Sang Eun [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

2007-07-01

We previously demonstrated dopamine (DA) release in the bilateral striatal regions following prefrontal repetitive transcranial magnetic stimulation (rTMS) in young subjects. Several lines of evidence support substantial age-related changes in human dopaminergic neurotransmission. One possible explanation is alteration of cortico striatal neural connection with aging. Therefore, we investigated how frontal activation by rTMS influences striatal DA release in the elderly with SPECT measurements of striatal binding of [123I]iodobenzamide (lBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy elderly male subjects (age, 64 3 y) were studied with brain [123I]IBZM SPECT under three conditions (resting, sham stimulation, and active rTMS over left dorsolateral prefrontal cortex (DLPFC)), while receiving a bolus plus constant infusion of [123I]IBZM. rTMS session consisted of three blocks. In each block, 15 trains of 2 sec duration were delivered with 10 Hz stimulation frequency and 100% motor threshold. Striatal V3', calculated as (striatal - occipital)/occipital radioactivity, was measured under equilibrium condition at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over left DLPFC induced no significant change in V3' in the right striatum compared with baseline condition (0.91 0.25 vs. 0.96 0.25, P = NS). Interestingly, left striatal V3' showed a significant increase after rTMS over left DLPFC compared with sham condition (1.09 0.33 vs. 0.93 0.27, P < 0.05; 17.0 11.1% increase). These results are discrepant from previous ones from young subjects, who showed frontal rTMS-induced reduction of striatal V3', indicating rTMS-induced striatal DA release. We found no significant striatal DA release induced by rTMS over DLPFC in healthy elderly subjects using in vivo binding competition techniques. These results may support an altered cortico striatal circuit in normal aging.

Transcranial magnetic stimulation of the dorsal lateral prefrontal cortex inhibits medial orbitofrontal activity in smokers.

Science.gov (United States)

Li, Xingbao; Sahlem, Gregory L; Badran, Bashar W; McTeague, Lisa M; Hanlon, Colleen A; Hartwell, Karen J; Henderson, Scott; George, Mark S

2017-12-01

Several studies have shown that repetitive transcranial magnetic stimulation (rTMS), applied to the dorsolateral prefrontal cortex (DLPFC), can reduce cue-elicited craving in smokers. Currently, the mechanism of this effect is unknown. We used functional magnetic resonance imaging (fMRI) to explore the effect of a single treatment of rTMS on cortical and sub-cortical neural activity in non-treatment seeking nicotine-dependent participants. We conducted a randomized, counterbalanced, crossover trial in which participants attended two experimental visits separated by at least 1 week. On the first visit, participants received either active, or sham rTMS (10 Hz, 5 s-on, 10 s-off, 100% motor threshold, 3,000 pulses) over the left DLPFC, and on the second visit they received the opposite condition (active or sham). Cue craving fMRI scans were completed before and after each rTMS session. A total of 11 non-treatment seeking nicotine-dependent cigarette smokers were enrolled in the study [six female, average age 39.7 ± 13.2, average cigarettes per day 17.3 ± 5.9]. Active rTMS decreased activity in the contralateral medial orbitofrontal cortex (mOFC) and ipsilateral nucleus accumbens (NAc) compared to sham rTMS. This preliminary data suggests that one session of rTMS applied to the DLPFC decreases brain activity in the NAc and mOFC in smokers. rTMS may exert its anti-craving effect by decreasing activity in the NAc and mOFC in smokers. Despite a small sample size, these findings warrant future rTMS/fMRI studies in addictions. (Am J Addict 2017;26:788-794). © 2017 American Academy of Addiction Psychiatry.

Transcranial direct current stimulation of the primary motor cortex improves word-retrieval in older adults.

Directory of Open Access Journals (Sweden)

Marcus eMeinzer

2014-09-01

Full Text Available Language facilitation by transcranial direct current stimulation (tDCS in healthy individuals has generated hope that tDCS may also allow improving language impairment after stroke (aphasia. However, current stimulation protocols have yielded variable results and may require identification of residual language cortex using functional magnetic resonance imaging (fMRI, which complicates incorporation into clinical practice. Based on previous behavioral studies that demonstrated improved language processing by motor system pre-activation, the present study assessed whether tDCS administered to the primary motor cortex (M1 can enhance language functions.This proof-of-concept study employed a sham-tDCS controlled, cross-over, within-subject design and assessed the impact of unilateral excitatory (anodal and bihemispheric (dual tDCS in eighteen healthy older adults during semantic word-retrieval and motor speech tasks. Simultaneous fMRI scrutinized the neural mechanisms underlying tDCS effects.Both active tDCS conditions significantly improved word-retrieval compared to sham-tDCS. The direct comparison of activity elicited by word-retrieval vs. motor-speech trials revealed bilateral frontal activity increases during both anodal- and dual-tDCS compared to sham-tDCS. This effect was driven by more pronounced deactivation of frontal regions during the motor-speech task, while activity during word-retrieval trials was unaffected by the stimulation. No effects were found in M1 and secondary motor regions.Our results show that tDCS administered to M1 can improve word-retrieval in healthy individuals, thereby providing a rationale to explore whether M1-tDCS may offer a novel approach to improve language functions in aphasia. fMRI revealed neural facilitation specifically during motor speech trials, which may have reduced switching costs between the overlapping neural systems for lexical retrieval and speech processing, thereby resulting in improved

Transcranial direct current stimulation of the primary motor cortex improves word-retrieval in older adults.

Science.gov (United States)

Meinzer, Marcus; Lindenberg, Robert; Sieg, Mira M; Nachtigall, Laura; Ulm, Lena; Flöel, Agnes

2014-01-01

Language facilitation by transcranial direct current stimulation (tDCS) in healthy individuals has generated hope that tDCS may also allow improving language impairment after stroke (aphasia). However, current stimulation protocols have yielded variable results and may require identification of residual language cortex using functional magnetic resonance imaging (fMRI), which complicates incorporation into clinical practice. Based on previous behavioral studies that demonstrated improved language processing by motor system pre-activation, the present study assessed whether tDCS administered to the primary motor cortex (M1) can enhance language functions. This proof-of-concept study employed a sham-tDCS controlled, cross-over, within-subject design and assessed the impact of unilateral excitatory (anodal) and bihemispheric (dual) tDCS in 18 healthy older adults during semantic word-retrieval and motor speech tasks. Simultaneous fMRI scrutinized the neural mechanisms underlying tDCS effects. Both active tDCS conditions significantly improved word-retrieval compared to sham-tDCS. The direct comparison of activity elicited by word-retrieval vs. motor-speech trials revealed bilateral frontal activity increases during both anodal- and dual-tDCS compared to sham-tDCS. This effect was driven by more pronounced deactivation of frontal regions during the motor-speech task, while activity during word-retrieval trials was unaffected by the stimulation. No effects were found in M1 and secondary motor regions. Our results show that tDCS administered to M1 can improve word-retrieval in healthy individuals, thereby providing a rationale to explore whether M1-tDCS may offer a novel approach to improve language functions in aphasia. Functional magnetic resonance imaging revealed neural facilitation specifically during motor speech trials, which may have reduced switching costs between the overlapping neural systems for lexical retrieval and speech processing, thereby resulting in

Plasma-based localized defect for switchable coupling applications

International Nuclear Information System (INIS)

Varault, Stefan; Gabard, Benjamin; Sokoloff, Jerome; Bolioli, Sylvain

2011-01-01

We report in this paper experimental measurements in order to validate the concept of switchable electromagnetic band gap filters based on plasma capillaries in the microwave regime. The plasma tube is embedded inside the structure to create a bistable (plasma on or off) punctual defect. We first investigate two kinds of discharge tubes: Ar-Hg and pure Ne, which we then use to experimentally achieve plasma-based reconfigurable applications, namely, a two-port coupler and a two-port demultiplexer.

Temperature-Switchable Agglomeration of Magnetic Particles Designed for Continuous Separation Processes in Biotechnology.

Science.gov (United States)

Paulus, Anja S; Heinzler, Raphael; Ooi, Huey Wen; Franzreb, Matthias

2015-07-08

The purpose of this work was the synthesis and characterization of thermally switchable magnetic particles for use in biotechnological applications such as protein purification and enzymatic conversions. Reversible addition-fragmentation chain-transfer polymerization was employed to synthesize poly(N-isopropylacrylamide) brushes via a "graft-from" approach on the surface of magnetic microparticles. The resulting particles were characterized by infrared spectroscopy and thermogravimetric analysis and their temperature-dependent agglomeration behavior was assessed. The influence of several factors on particle agglomeration (pH, temperature, salt type, and particle concentration) was evaluated. The results showed that a low pH value (pH 3-4), a kosmotropic salt (ammonium sulfate), and a high particle concentration (4 g/L) resulted in improved agglomeration at elevated temperature (40 °C). Recycling of particles and reversibility of the temperature-switchable agglomeration were successfully demonstrated for ten heating-cooling cycles. Additionally, enhanced magnetic separation was observed for the modified particles. Ionic monomers were integrated into the polymer chain to create end-group functionalized particles as well as two- and three-block copolymer particles for protein binding. The adsorption of lactoferrin, bovine serum albumin, and lysozyme to these ion exchange particles was evaluated and showed a binding capacity of up to 135 mg/g. The dual-responsive particles combined magnetic and thermoresponsive properties for switchable agglomeration, easy separability, and efficient protein adsorption.

Empathy moderates the effect of repetitive transcranial magnetic stimulation of the right dorsolateral prefrontal cortex on costly punishment.

Directory of Open Access Journals (Sweden)

Martin Brüne

Full Text Available Humans incur considerable costs to punish unfairness directed towards themselves or others. Recent studies using repetitive transcranial magnetic stimulation (rTMS suggest that the right dorsolateral prefrontal cortex (DLPFC is causally involved in such strategic decisions. Presently, two partly divergent hypotheses are discussed, suggesting either that the right DLPFC is necessary to control selfish motives by implementing culturally transmitted social norms, or is involved in suppressing emotion-driven prepotent responses to perceived unfairness. Accordingly, we studied the role of the DLPFC in costly (i.e. third party punishment by applying rTMS to the left and right DLPFC before playing a Dictator Game with the option to punish observed unfair behavior (DG-P. In addition, sham stimulation took place. Individual differences in empathy were assessed with the German version of the Interpersonal Reactivity Index. Costly punishment increased (non-significantly upon disruption of the right--but not the left--DLPFC as compared to sham stimulation. However, empathy emerged as a highly significant moderator variable of the effect of rTMS over the right, but not left, DLPFC, suggesting that the right DLPFC is involved in controlling prepotent emotional responses to observed unfairness, depending on individual differences in empathy.

Modulation of risk-taking in marijuana users by transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC).

Science.gov (United States)

Boggio, Paulo S; Zaghi, Soroush; Villani, Ana Beatriz; Fecteau, Shirley; Pascual-Leone, Alvaro; Fregni, Felipe

2010-12-01

Cognitive deficits that are reported in heavy marijuana users (attention, memory, affect perception, decision-making) appear to be completely reversible after a prolonged abstinence period of about 28 days. However, it remains unclear whether the reversibility of these cognitive deficits indicates that (1) chronic marijuana use is not associated with long-lasting changes in cortical networks or (2) that such changes occur but the brain adapts to and compensates for the drug-induced changes. Therefore, we examined whether chronic marijuana smokers would demonstrate a differential pattern of response in comparison to healthy volunteers on a decision-making paradigm (Risk Task) while undergoing sham or active transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC). Twenty-five chronic marijuana users who were abstinent for at least 24h were randomly assigned to receive left anodal/right cathodal tDCS of DLPFC (n=8), right anodal/left cathodal tDCS of DLPFC (n=9), or sham stimulation (n=8); results on Risk Task during sham/active tDCS were compared to healthy volunteers from a previously published dataset. Chronic marijuana users demonstrated more conservative (i.e. less risky) decision-making during sham stimulation. While right anodal stimulation of the DLPFC enhanced conservative decision-making in healthy volunteers, both right anodal and left anodal DLPFC stimulation increased the propensity for risk-taking in marijuana users. These findings reveal alterations in the decision-making neural networks among chronic marijuana users. Finally, we also assessed the effects of tDCS on marijuana craving and observed that right anodal/left cathodal tDCS of DLPFC is significantly associated with a diminished craving for marijuana. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Transcranial Direct Current Stimulation (tDCS) Enhances the Excitability of Trigemino-Facial Reflex Circuits.

Science.gov (United States)

Cabib, Christopher; Cipullo, Federica; Morales, Merche; Valls-Solé, Josep

2016-01-01

Transcranial direct current stimulation (tDCS) causes a tiny burning sensation through activation of local cutaneous trigeminal afferents. Trigeminal sensory inputs from tDCS may generate excitability changes in the trigemino-facial reflex circuits. Sixteen healthy volunteers were submitted to 20 minutes tDCS sessions with two types of electrode-montage conditions: 1. Real vs Sham 'bi-hemispheric' tDCS (cathode/anode: C4/C3), for blinded assessment of effects, and 2. 'uni-hemispheric' tDCS (cathode/anode: Fp3/C3), for assessment of laterality of the effects. Supraorbital nerve stimuli were used to obtain blink reflexes before, during (10 minutes from onset) and after (30 minutes from onset) the tDCS session. Outcome measures were R2 habituation (R2H) to repeated stimuli, the blink reflex excitability recovery (BRER) to paired stimuli and the blink reflex inhibition by a prepulse (BRIP). Real but not sham bi-hemispheric tDCS caused a significant decrease of R2H and leftward shift of BRER curve (p tDCS on BRER and BRIP were larger on ipsilateral than on contralateral blink reflexes (p tDCS enhances the excitability of trigemino-facial reflex circuits. The finding of larger ipsilateral than contralateral effects suggests that sensitization through cutaneous trigeminal afferents adds on other possible mechanisms such as activation of cortico-nuclear or cortico-reticular connections. Copyright © 2016 Elsevier Inc. All rights reserved.

Safety of primed repetitive transcranial magnetic stimulation and modified constraint-induced movement therapy in a randomized controlled trial in pediatric hemiparesis.

Science.gov (United States)

Gillick, Bernadette T; Krach, Linda E; Feyma, Tim; Rich, Tonya L; Moberg, Kelli; Menk, Jeremiah; Cassidy, Jessica; Kimberley, Teresa; Carey, James R

2015-04-01

To investigate the safety of combining a 6-Hz primed low-frequency repetitive transcranial magnetic stimulation (rTMS) intervention in the contralesional hemisphere with a modified constraint-induced movement therapy (mCIMT) program in children with congenital hemiparesis. Phase 1 randomized, double-blinded, placebo-controlled pretest/posttest trial. University academic facility and pediatric specialty hospital. Subjects (N = 19; age range, 8-17 y) with congenital hemiparesis caused by ischemic stroke or periventricular leukomalacia. No subject withdrew because of adverse events. All subjects included completed the study. Subjects were randomized to 1 of 2 groups: either real rTMS plus mCIMT (n = 10) or sham rTMS plus mCIMT (n = 9). Adverse events, physician assessment, ipsilateral hand function, stereognosis, cognitive function, subject report of symptoms assessment, and subject questionnaire. No major adverse events occurred. Minor adverse events were found in both groups. The most common events were headaches (real: 50%, sham: 89%; P = .14) and cast irritation (real: 30%, sham: 44%; P = .65). No differences between groups in secondary cognitive and unaffected hand motor measures were found. Primed rTMS can be used safely with mCIMT in congenital hemiparesis. We provide new information on the use of rTMS in combination with mCIMT in children. These findings could be useful in research and future clinical applications in advancing function in congenital hemiparesis. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

A Systematic Review on the Acceptability and Tolerability of Transcranial Direct Current Stimulation Treatment in Neuropsychiatry Trials.

Science.gov (United States)

Aparício, Luana V M; Guarienti, Fabiana; Razza, Lais Boralli; Carvalho, André F; Fregni, Felipe; Brunoni, André Russowsky

2016-01-01

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation investigated as a treatment for several neuropsychiatric disorders. Notwithstanding tDCS-induced adverse events (AEs) are considered to be low and transient, systematic review analyses on safety and tolerability of tDCS derive mostly from single-session studies. To investigate the tolerability (rate of AEs) and acceptability (rate of dropouts) of tDCS. Systematic review and meta-analysis of tDCS randomized, sham-controlled trials in healthy or neuropsychiatric adult samples from the first date available to March 9, 2016. We only included parallel studies performing at least 5 tDCS sessions. An adapted version of CONSORT guidelines for reporting harms outcomes was used to evaluate AE reporting. Sixty-four studies (2262 participants) were included. They had a low risk of publication bias and methodological bias for the items assessed. Dropout rates in active and sham tDCS groups were, respectively, 6% and 7.2% (OR = 0.82 [0.59-1.14]). However, almost half of studies reported no dropouts and only 23.4% reported its reasons; when reported, the most frequent reasons were AEs and protocol violation. A tolerability meta-analysis was not performed, as most studies did not report AEs. The quality of AEs reporting was also limited, particularly in smaller studies and stroke studies. Although overall dropout rate was low and similar in active and sham groups, studies did not adequately describe AEs. An updated questionnaire and guidelines for assessment of AEs in tDCS trials are proposed in order to standardize the reporting of AE in the field. Copyright © 2016 Elsevier Inc. All rights reserved.

Increase in cortical pyramidal cell excitability accompanies depression-like behavior in mice: a transcranial magnetic stimulation study.

Science.gov (United States)

Sun, Peng; Wang, Furong; Wang, Li; Zhang, Yu; Yamamoto, Ryo; Sugai, Tokio; Zhang, Qing; Wang, Zhengda; Kato, Nobuo

2011-11-09

Clinical evidence suggests that cortical excitability is increased in depressives. We investigated its cellular basis in a mouse model of depression. In a modified version of forced swimming (FS), mice were initially forced to swim for 5 consecutive days and then were treated daily with repetitive transcranial magnetic stimulation (rTMS) or sham treatment for the following 4 weeks without swimming. On day 2 through day 5, the mice manifested depression-like behaviors. The next and last FS was performed 4 weeks later, which revealed a 4 week maintenance of depression-like behavior in the sham mice. In slices from the sham controls, excitability in cingulate cortex pyramidal cells was elevated in terms of membrane potential and frequencies of spikes evoked by current injection. Depolarized resting potential was shown to depend on suppression of large conductance calcium-activated potassium (BK) channels. This BK channel suppression was confirmed by measuring spike width, which depends on BK channels. Chronic rTMS treatment during the 4 week period significantly reduced the depression-like behavior. In slices obtained from the rTMS mice, normal excitability and BK channel activity were recovered. Expression of a scaffold protein Homer1a was reduced by the FS and reversed by rTMS in the cingulate cortex. Similar recovery in the same behavioral, electrophysiological, and biochemical features was observed after chronic imipramine treatment. The present study demonstrated that manifestation and disappearance of depression-like behavior are in parallel with increase and decrease in cortical neuronal excitability in mice and suggested that regulation of BK channels by Homer1a is involved in this parallelism.

Repetitive transcranial magnetic stimulation in cervical dystonia: effect of site and repetition in a randomized pilot trial.

Directory of Open Access Journals (Sweden)

Sarah Pirio Richardson

Full Text Available Dystonia is characterized by abnormal posturing due to sustained muscle contraction, which leads to pain and significant disability. New therapeutic targets are needed in this disorder. The objective of this randomized, sham-controlled, blinded exploratory study is to identify a specific motor system target for non-invasive neuromodulation and to evaluate this target in terms of safety and tolerability in the cervical dystonia (CD population. Eight CD subjects were given 15-minute sessions of low-frequency (0.2 Hz repetitive transcranial magnetic stimulation (rTMS over the primary motor cortex (MC, dorsal premotor cortex (dPM, supplementary motor area (SMA, anterior cingulate cortex (ACC and a sham condition with each session separated by at least two days. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS score was rated in a blinded fashion immediately pre- and post-intervention. Secondary outcomes included physiology and tolerability ratings. The mean change in TWSTRS severity score by site was 0.25 ± 1.7 (ACC, -2.9 ± 3.4 (dPM, -3.0 ± 4.8 (MC, -0.5 ± 1.1 (SHAM, and -1.5 ± 3.2 (SMA with negative numbers indicating improvement in symptom control. TWSTRS scores decreased from Session 1 (15.1 ± 5.1 to Session 5 (11.0 ± 7.6. The treatment was tolerable and safe. Physiology data were acquired on 6 of 8 subjects and showed no change over time. These results suggest rTMS can modulate CD symptoms. Both dPM and MC are areas to be targeted in further rTMS studies. The improvement in TWSTRS scores over time with multiple rTMS sessions deserves further evaluation.

Exploring the efficacy of a 5-day course of transcranial direct current stimulation (TDCS) on depression and memory function in patients with well-controlled temporal lobe epilepsy.

Science.gov (United States)

Liu, Anli; Bryant, Andrew; Jefferson, Ashlie; Friedman, Daniel; Minhas, Preet; Barnard, Sarah; Barr, William; Thesen, Thomas; O'Connor, Margaret; Shafi, Mouhsin; Herman, Susan; Devinsky, Orrin; Pascual-Leone, Alvaro; Schachter, Steven

2016-02-01

Depression and memory dysfunction significantly impact the quality of life of patients with epilepsy. Current therapies for these cognitive and psychiatric comorbidities are limited. We explored the efficacy and safety of transcranial direct current stimulation (TDCS) for treating depression and memory dysfunction in patients with temporal lobe epilepsy (TLE). Thirty-seven (37) adults with well-controlled TLE were enrolled in a double-blinded, sham-controlled, randomized, parallel-group study of 5 days of fixed-dose (2 mA, 20 min) TDCS. Subjects were randomized to receive either real or sham TDCS, both delivered over the left dorsolateral prefrontal cortex. Patients received neuropsychological testing and a 20-minute scalp EEG at baseline immediately after the TDCS course and at 2- and 4-week follow-up. There was improvement in depression scores immediately after real TDCS, but not sham TDCS, as measured by changes in the Beck Depression Inventory (BDI change: -1.68 vs. 1.27, pTDCS as a safe and well-tolerated nonpharmacologic approach to improving depressive symptoms in patients with well-controlled TLE. However, there were no changes in memory function immediately following or persisting after a stimulation course. Further studies may determine optimal stimulation parameters for maximal mood benefit. Copyright © 2015. Published by Elsevier Inc.

Use of 'sham' radiotherapy in randomized clinical trials

International Nuclear Information System (INIS)

Schwarz, F.; Christie, D.

2008-01-01

The objective of this systematic review was to identify quality trials that use sham radiotherapy in their design and review them to determine its potential value. The Cochrane Library, Pubmed and a Reference Search served as data sources. Trials were included if they met a minimum quality score of 3 on a validated assessment instrument (which assesses randomization, control and blinding) and if they compared sham radiotherapy to active treatment. External beam therapy and brachytherapy trials were considered. Twenty-six trials were identified, collectively including 2663 participants in the period of 1970-2004. All the trials studied the value of radiotherapy for treatment or prevention of benign diseases, including multiple sclerosis, coronary artery restenosis, age-related macular degeneration and Graves' ophthalmopathy. There were no trials relating to the use of radiotherapy in the treatment of malignancy. This review showed that it is possible to carry out sham radiotherapy with due regard for ethical concerns, with effective blinding and high levels of patient acceptance. Large sample sizes with multicentre trial designs were achievable. Although the statistical philosophy for using sham radiotherapy in trials is legitimate, it is no longer routinely used.

Clinical Applications of Transcranial Magnetic Stimulation in Pediatric Neurology.

Science.gov (United States)

Narayana, Shalini; Papanicolaou, Andrew C; McGregor, Amy; Boop, Frederick A; Wheless, James W

2015-08-01

Noninvasive brain stimulation is now an accepted technique that is used as a diagnostic aid and in the treatment of neuropsychiatric disorders in adults, and is being increasingly used in children. In this review, we will discuss the basic principles and safety of one noninvasive brain stimulation method, transcranial magnetic stimulation. Improvements in the spatial accuracy of transcranial magnetic stimulation are described in the context of image-guided transcranial magnetic stimulation. The article describes and provides examples of the current clinical applications of transcranial magnetic stimulation in children as an aid in the diagnosis and treatment of neuropsychiatric disorders and discusses future potential applications. Transcranial magnetic stimulation is a noninvasive tool that is safe for use in children and adolescents for functional mapping and treatment, and for many children it aids in the preoperative evaluation and the risk-benefit decision making. © The Author(s) 2014.

The effects of transcranial direct current stimulation in patients with neuropathic pain from spinal cord injury.

Science.gov (United States)

Ngernyam, Niran; Jensen, Mark P; Arayawichanon, Preeda; Auvichayapat, Narong; Tiamkao, Somsak; Janjarasjitt, Suparerk; Punjaruk, Wiyada; Amatachaya, Anuwat; Aree-uea, Benchaporn; Auvichayapat, Paradee

2015-02-01

Transcranial direct current stimulation (tDCS) has demonstrated efficacy for reducing neuropathic pain, but the respective mechanisms remain largely unknown. The current study tested the hypothesis that pain reduction with tDCS is associated with an increase in the peak frequency spectrum density in the theta-alpha range. Twenty patients with spinal cord injury and bilateral neuropathic pain received single sessions of both sham and anodal tDCS (2 mA) over the left primary motor area (M1) for 20 min. Treatment order was randomly assigned. Pre- to post-procedure changes in pain intensity and peak frequency of electroencephalogram spectral analysis were compared between treatment conditions. The active treatment condition (anodal tDCS over M1) but not sham treatment resulted in significant decreases in pain intensity. In addition, consistent with the study hypothesis, peak theta-alpha frequency (PTAF) assessed from an electrode placed over the site of stimulation increased more from pre- to post-session among participants in the active tDCS condition, relative to those in the sham tDCS condition. Moreover, we found a significant association between a decrease in pain intensity and an increase in PTAF at the stimulation site. The findings are consistent with the possibility that anodal tDCS over the left M1 may be effective, at least in part, because it results in an increase in M1 cortical excitability, perhaps due to a pain inhibitory effect of motor cortex stimulation that may influence the descending pain modulation system. Future research is needed to determine if there is a causal association between increased left anterior activity and pain reduction. The results provide new findings regarding the effects of tDCS on neuropathic pain and brain oscillation changes. Copyright © 2014 International Federation of Clinical Neurophysiology. All rights reserved.

Single-Session Transcranial Direct Current Stimulation Temporarily Improves Symptoms, Mood, and Self-Regulatory Control in Bulimia Nervosa: A Randomised Controlled Trial.

Directory of Open Access Journals (Sweden)

Maria Kekic

Full Text Available Evidence suggests that pathological eating behaviours in bulimia nervosa (BN are underpinned by alterations in reward processing and self-regulatory control, and by functional changes in neurocircuitry encompassing the dorsolateral prefrontal cortex (DLPFC. Manipulation of this region with transcranial direct current stimulation (tDCS may therefore alleviate symptoms of the disorder.This double-blind sham-controlled proof-of-principle trial investigated the effects of bilateral tDCS over the DLPFC in adults with BN.Thirty-nine participants (two males received three sessions of tDCS in a randomised and counterbalanced order: anode right/cathode left (AR/CL, anode left/cathode right (AL/CR, and sham. A battery of psychological/neurocognitive measures was completed before and after each session and the frequency of bulimic behaviours during the following 24-hours was recorded.AR/CL tDCS reduced eating disorder cognitions (indexed by the Mizes Eating Disorder Cognitions Questionnaire-Revised when compared to AL/CR and sham tDCS. Both active conditions suppressed the self-reported urge to binge-eat and increased self-regulatory control during a temporal discounting task. Compared to sham stimulation, mood (assessed with the Profile of Mood States improved after AR/CL but not AL/CR tDCS. Lastly, the three tDCS sessions had comparable effects on the wanting/liking of food and on bulimic behaviours during the 24 hours post-stimulation.These data suggest that single-session tDCS transiently improves symptoms of BN. They also help to elucidate possible mechanisms of action and highlight the importance of selecting the optimal electrode montage. Multi-session trials are needed to determine whether tDCS has potential for development as a treatment for adult BN.

Construction of a 4 Zeptoliters Switchable 3D DNA Box Origami

DEFF Research Database (Denmark)

Zadegan, Reza Mohammad; Jepsen, Mette DE; Thomsen, Karen E

2012-01-01

The DNA origami technique is a recently developed self-assembly method that allows construction of 3D objects at the nanoscale for various applications. In the current study we report the production of a 18 × 18 × 24 nm3 hollow DNA box origami structure with a switchable lid. The structure...

The Efficacy of Daily Prefrontal Repetitive Transcranial Magnetic Stimulation (rTMS) for Burning Mouth Syndrome (BMS): A Randomized Controlled Single-blind Study.

Science.gov (United States)

Umezaki, Yojiro; Badran, Bashar W; DeVries, William H; Moss, Jkeonye; Gonzales, Theresa; George, Mark S

2016-01-01

Burning mouth syndrome (BMS) is a burning oral sensation without any corresponding abnormal findings. In some cases, BMS is refractory to pharmacologic treatments. Repetitive transcranial magnetic stimulation (rTMS) over left prefrontal cortex induces analgesic effect in both acute and chronic pain. However, its effect for BMS has not been evaluated. The aim of this randomized, controlled, single-blind study was to assess the efficacy of prefrontal rTMS for BMS. Twenty patients with BMS were recruited and randomized to receive 30,000 pulses in total at 10 Hz TMS (n = 12) or sham TMS (n = 8). We assessed the change of BMS pain condition, functional status and mood until 2 months after the beginning of treatment. In the real group, the BMS pain intensity decreased 67%, and 75% of the patients reported >50% pain decrease on final assessment compared to baseline, without heavy side effects. There was significant pain reduction in subjects in the real group immediately after 1 week of treatment, whereas there was none in those in the sham group. Similar tendency was confirmed in change of functional status. Mood and the affective aspect of pain were not changed in this study. BMS pain was significantly improved with 2 weeks of treatment of high frequency rTMS over left DLPFC compared to sham stimulation. Further study is needed to refine and improve TMS as a potential treatment of BMS. Copyright © 2016 Elsevier Inc. All rights reserved.

Switchable cell trapping using superparamagnetic beads

Energy Technology Data Exchange (ETDEWEB)

Bryan, M. T.; Smith, K. H.; Real, M. E.; Bashir, M. A.; Fry, P. W.; Fischer, P.; Im, M.-Y.; Schrefl, T.; Allwood, D. A.; Haycock, J. W.

2010-04-30

Ni{sub 81}Fe{sub 19} microwires are investigated as the basis of a switchable template for positioning magnetically-labeled neural Schwann cells. Magnetic transmission X-ray microscopy and micromagnetic modeling show that magnetic domain walls can be created or removed in zigzagged structures by an applied magnetic field. Schwann cells containing superparamagnetic beads are trapped by the field emanating from the domain walls. The design allows Schwann cells to be organized on a surface to form a connected network and then released from the surface if required. As aligned Schwann cells can guide nerve regeneration, this technique is of value for developing glial-neuronal co-culture models in the future treatment of peripheral nerve injuries.

Add-on Effects of Repetitive Transcranial Magnetic Stimulation on Subacute Aphasia Therapy: Enhanced Improvement of Functional Communication and Basic Linguistic Skills. A Randomized Controlled Study.

Science.gov (United States)

Rubi-Fessen, Ilona; Hartmann, Alexander; Huber, Walter; Fimm, Bruno; Rommel, Thomas; Thiel, Alexander; Heiss, Wolf-Dieter

2015-11-01

To determine to what extent repetitive transcranial magnetic stimulation (rTMS) combined with speech and language therapy improves functional communication and basic linguistic skills of individuals with subacute aphasia. Randomized, blinded, and sham-controlled study. Neurologic rehabilitation hospital. Participants (N=30) with subacute aphasia after stroke. During a 2-week treatment period, half of the participants received 10 sessions of 20-minute inhibitory 1-Hz rTMS over the right inferior frontal gyrus (Brodmann area 45), and the other half received sham stimulation. Directly thereafter, all the participants underwent 45 minutes of speech and language therapy. Aachen Aphasia Test, Amsterdam-Nijmegen Everyday Language Test (ANELT), a naming screening, and subscales of the FIM, all assessed the day before and the day after treatment period. The participants who received real rTMS significantly improved with respect to all 10 measures of basic linguistic skills and functional communication, whereas sham-treated participants significantly improved in only 6 of 10 measures (paired t tests, Pcommunication (ANELT) (repeated-measures analysis of variance, P≤.05). For the first time, this study has demonstrated that basic linguistic skills as well as functional communication are bolstered by combining rTMS and behavioral language therapy in patients with subacute aphasia. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Transcranial direct current stimulation (tDCS) neuromodulatory effects on mechanical hyperalgesia and cortical BDNF levels in ovariectomized rats.

Science.gov (United States)

da Silva Moreira, Sônia Fátima; Medeiros, Liciane Fernandes; de Souza, Andressa; de Oliveira, Carla; Scarabelot, Vanessa Leal; Fregni, Felipe; Caumo, Wolnei; Torres, Iraci L S

2016-01-15

Epidemiological studies show that painful disorders are more prevalent in women than in men, and the transcranial direct current stimulation (tDCS) technique has been tested in chronic pain states. We explored the effect of tDCS on pain behavior and brain-derived neurotrophic factor (BDNF) levels in ovariectomized rats. Forty-five female Wistar adult rats were distributed into five groups: control (CT), ovariectomy + tDCS (OT), ovariectomy + sham tDCS (OS), sham ovariectomy + tDCS (ST), and sham ovariectomy+shamtDCS (SS). The rats were subjected to cathodal tDCS. The vaginal cytology and the estradiol levels confirmed the hormonal status. In addition, nociceptive behavior was evaluated using the tail-flick, von Frey, and hot-plate tests, as well as the BDNF levels in the serum, hypothalamus, hippocampus, spinal cord, and cerebral cortex. One-way analysis of variance (ANOVA) or two-way ANOVA was used for statistical analysis, followed by the Bonferroni, and P-value b 0.05 was considered significant. The ovariectomized animals presented a hypersensitivity response in the hot-plate (P b 0.01) and von Frey (P b 0.05) tests, as well as increased serum BDNF (P b 0.05) and decreased hypothalamic BDNF (P b 0.01) levels. The OT, OS, ST, and SS groups showed decreased hippocampal BDNF levels as compared with the control group (P b 0.001). The interaction between tDCS and ovariectomy on the cortical BDNF levels (P b 0.01) was observed. The ovariectomy induced nociceptive hypersensitivity and altered serum and hypothalamic BDNF levels. The cathodal tDCS partially reversed nociceptive hypersensitivity.

Ferroelectric nanostructure having switchable multi-stable vortex states

Science.gov (United States)

Naumov, Ivan I [Fayetteville, AR; Bellaiche, Laurent M [Fayetteville, AR; Prosandeev, Sergey A [Fayetteville, AR; Ponomareva, Inna V [Fayetteville, AR; Kornev, Igor A [Fayetteville, AR

2009-09-22

A ferroelectric nanostructure formed as a low dimensional nano-scale ferroelectric material having at least one vortex ring of polarization generating an ordered toroid moment switchable between multi-stable states. A stress-free ferroelectric nanodot under open-circuit-like electrical boundary conditions maintains such a vortex structure for their local dipoles when subject to a transverse inhomogeneous static electric field controlling the direction of the macroscopic toroidal moment. Stress is also capable of controlling the vortex's chirality, because of the electromechanical coupling that exists in ferroelectric nanodots.

Chronic transcranial focal stimulation from tripolar concentric ring electrodes does not disrupt memory formation in rats.

Science.gov (United States)

Luby, Matthew D; Makeyev, Oleksandr; Besio, Walter G

2014-01-01

Non-invasive electrical brain stimulation has shown potential utility as a treatment for seizures in epilepsy patients. Transcranial focal stimulation (TFS) via tripolar concentric ring electrodes (TCREs) has been effective in reducing seizure severity in acute rodent models, but it has yet to be determined whether or not it will serve as a viable long-term treatment strategy. Prior experiments indicate that a single dose of TFS via TCRE does not impact short- or long-term memory formation. The present study investigated if five daily doses of TFS via a TCRE on the scalp affected the memory. The spontaneous object recognition (SOR) test was used to evaluate the memory. Sham and TFS-treated groups were evaluated and both showed comparable levels of preference for novel objects, indicating successful memory formation. More work on repeated dosage strategies is important for establishing the safety and efficacy of TFS as a putative treatment.

Can a single pulse transcranial magnetic stimulation targeted to the motor cortex interrupt pain processing?

Science.gov (United States)

Kisler, Lee-Bareket; Gurion, Ilan; Granovsky, Yelena; Sinai, Alon; Sprecher, Elliot; Shamay-Tsoory, Simone; Weissman-Fogel, Irit

2018-01-01

The modulatory role of the primary motor cortex (M1), reflected by an inhibitory effect of M1-stimulation on clinical pain, motivated us to deepen our understanding of M1's role in pain modulation. We used Transcranial Magnetic Stimulation (TMS)-induced virtual lesion (VL) to interrupt with M1 activity during noxious heat pain. We hypothesized that TMS-VL will effect experimental pain ratings. Three VL protocols were applied consisting of single-pulse TMS to transiently interfere with right M1 activity: (1) VLM1- TMS applied to 11 subjects, 20 msec before the individual's first pain-related M1 peak activation, as determined by source analysis (sLORETA), (2) VL-50 (N = 16; TMS applied 50 ms prior to noxious stimulus onset), and (3) VL+150 (N = 16; TMS applied 150 ms after noxious stimulus onset). Each protocol included 3 conditions ('pain-alone', ' TMS-VL', and 'SHAM-VL'), each consisted of 30 noxious heat stimuli. Pain ratings were compared, in each protocol, for TMS-VL vs. SHAM-VL and vs. pain-alone conditions. Repeated measures analysis of variance, corrected for multiple comparisons revealed no significant differences in the pain ratings between the different conditions within each protocol. Therefore, our results from this exploratory study suggest that a single pulse TMS-induced VL that is targeted to M1 failed to interrupt experimental pain processing in the specific three stimulation timing examined here.

Prefrontal transcranial direct current stimulation alters activation and connectivity in cortical and subcortical reward systems: a tDCS-fMRI study.

Science.gov (United States)

Weber, Matthew J; Messing, Samuel B; Rao, Hengyi; Detre, John A; Thompson-Schill, Sharon L

2014-08-01

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique used both experimentally and therapeutically to modulate regional brain function. However, few studies have directly measured the aftereffects of tDCS on brain activity or examined changes in task-related brain activity consequent to prefrontal tDCS. To investigate the neural effects of tDCS, we collected fMRI data from 22 human subjects, both at rest and while performing the Balloon Analog Risk Task (BART), before and after true or sham transcranial direct current stimulation. TDCS decreased resting blood perfusion in orbitofrontal cortex and the right caudate and increased task-related activity in the right dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) in response to losses but not wins or increasing risk. Network analysis showed that whole-brain connectivity of the right ACC correlated positively with the number of pumps subjects were willing to make on the BART, and that tDCS reduced connectivity between the right ACC and the rest of the brain. Whole-brain connectivity of the right DLPFC also correlated negatively with pumps on the BART, as prior literature would suggest. Our results suggest that tDCS can alter activation and connectivity in regions distal to the electrodes. Copyright © 2014 Wiley Periodicals, Inc.

Synthesis and Guest Recognition of Switchable Pt-Salphen Based Molecular Tweezers

Directory of Open Access Journals (Sweden)

Lorien Benda

2018-04-01

Full Text Available Molecular tweezers are artificial receptors that have an open cavity generated by two recognition units pre-organized by a spacer. Switchable molecular tweezers, using a stimuli-responsive spacer, are particularly appealing as prototypes of the molecular machines that combine mechanical motion and allosteric recognition properties. In this present study, the synthesis of switchable molecular tweezers composed of a central terpyridine unit substituted in 4,4″ positions by two Pt(II-salphen complexes is reported. The terpyridine ligand can be reversibly converted upon Zn(II coordination from a free ‘U’-shaped closed form to a coordinated ‘W’ open form. This new substitution pattern enables a reverse control of the mechanical motion compared to the previously reported 6,6″ substituted terpyridine-based tweezers. Guest binding studies with aromatic guests showed an intercalation of coronene in the cavity created by the Pt-salphen moieties in the closed conformation. The formation of 1:1 host-guest complex was investigated by a combination of NMR studies and DFT calculations.

Transcranial direct current stimulation of the posterior parietal cortex modulates arithmetic learning.

Science.gov (United States)

Grabner, Roland H; Rütsche, Bruno; Ruff, Christian C; Hauser, Tobias U

2015-07-01

The successful acquisition of arithmetic skills is an essential step in the development of mathematical competencies and has been associated with neural activity in the left posterior parietal cortex (PPC). It is unclear, however, whether this brain region plays a causal role in arithmetic skill acquisition and whether arithmetic learning can be modulated by means of non-invasive brain stimulation of this key region. In the present study we addressed these questions by applying transcranial direct current stimulation (tDCS) over the left PPC during a short-term training that simulates the typical path of arithmetic skill acquisition (specifically the transition from effortful procedural to memory-based problem-solving strategies). Sixty participants received either anodal, cathodal or sham tDCS while practising complex multiplication and subtraction problems. The stability of the stimulation-induced learning effects was assessed in a follow-up test 24 h after the training. Learning progress was modulated by tDCS. Cathodal tDCS (compared with sham) decreased learning rates during training and resulted in poorer performance which lasted over 24 h after stimulation. Anodal tDCS showed an operation-specific improvement for subtraction learning. Our findings extend previous studies by demonstrating that the left PPC is causally involved in arithmetic learning (and not only in arithmetic performance) and that even a short-term tDCS application can modulate the success of arithmetic knowledge acquisition. Moreover, our finding of operation-specific anodal stimulation effects suggests that the enhancing effects of tDCS on learning can selectively affect just one of several cognitive processes mediated by the stimulated area. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation

Science.gov (United States)

Kwon, Yong Hyun; Jang, Sung Ho

2012-01-01

We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel counts and blood oxygenation level-dependent signal intensities in the right primary sensorimotor cortex regions were estimated and compared between the two transcranial direct current stimulation conditions. Our results showed that dual-hemispheric transcranial direct current stimulation induced greater cortical activities than single-hemispheric transcranial direct current stimulation. These findings suggest that dual-hemispheric transcranial direct current stimulation may provide more effective cortical stimulation than single-hemispheric transcranial direct current stimulation. PMID:25624815

The effect of the interval-between-sessions on prefrontal transcranial direct current stimulation (tDCS) on cognitive outcomes: a systematic review and meta-analysis.

Science.gov (United States)

Dedoncker, Josefien; Brunoni, Andre R; Baeken, Chris; Vanderhasselt, Marie-Anne

2016-10-01

Recently, there has been wide interest in the effects of transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC) on cognitive functioning. However, many methodological questions remain unanswered. One of them is whether the time interval between active and sham-controlled stimulation sessions, i.e. the interval between sessions (IBS), influences DLPFC tDCS effects on cognitive functioning. Therefore, a systematic review and meta-analysis was performed of experimental studies published in PubMed, Science Direct, and other databases from the first data available to February 2016. Single session sham-controlled within-subject studies reporting the effects of tDCS of the DLPFC on cognitive functioning in healthy controls and neuropsychiatric patients were included. Cognitive tasks were categorized in tasks assessing memory, attention, and executive functioning. Evaluation of 188 trials showed that anodal vs. sham tDCS significantly decreased response times and increased accuracy, and specifically for the executive functioning tasks, in a sample of healthy participants and neuropsychiatric patients (although a slightly different pattern of improvement was found in analyses for both samples separately). The effects of cathodal vs. sham tDCS (45 trials), on the other hand, were not significant. IBS ranged from less than 1 h to up to 1 week (i.e. cathodal tDCS) or 2 weeks (i.e. anodal tDCS). This IBS length had no influence on the estimated effect size when performing a meta-regression of IBS on reaction time and accuracy outcomes in all three cognitive categories, both for anodal and cathodal stimulation. Practical recommendations and limitations of the study are further discussed.

A Kohn-Sham system at zero temperature

International Nuclear Information System (INIS)

Cornean, H; Hoke, K; Neidhardt, H; Racec, P N; Rehberg, J

2008-01-01

A one-dimensional Kohn-Sham system for spin particles is considered which effectively describes semiconductor nanostructures, and which is investigated at zero temperature. We prove the existence of solutions and derive a priori estimates. For this purpose we find estimates for eigenvalues of the Schroedinger operator with effective Kohn-Sham potential and obtain W 1,2 -bounds of the associated particle density operator. Afterwards, compactness and continuity results allow us to apply Schauder's fixed point theorem. In the case of vanishing exchange-correlation potential uniqueness is shown by monotonicity arguments. Finally, we investigate the behavior of the system if the temperature approaches zero

Noninvasive Transcranial Brain Stimulation and Pain

OpenAIRE

Rosen, Allyson C.; Ramkumar, Mukund; Nguyen, Tam; Hoeft, Fumiko

2009-01-01

Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are two noninvasive brain stimulation techniques that can modulate activity in specific regions of the cortex. At this point, their use in brain stimulation is primarily investigational; however, there is clear evidence that these tools can reduce pain and modify neurophysiologic correlates of the pain experience. TMS has also been used to predict response to surgically implanted stimulation for the tre...

The effects of prefrontal cortex transcranial direct current stimulation (tDCS) on food craving and temporal discounting in women with frequent food cravings.

Science.gov (United States)

Kekic, Maria; McClelland, Jessica; Campbell, Iain; Nestler, Steffen; Rubia, Katya; David, Anthony S; Schmidt, Ulrike

2014-07-01

Bulimia nervosa, binge-eating disorder, and some forms of obesity are characterised by compulsive overeating that is often precipitated by food craving. Transcranial direct current stimulation (tDCS) has been used to suppress food cravings, but there is insufficient evidence to support its application in clinical practice. Furthermore, the potential moderating role of impulsivity has not been considered. This study used a randomised within-subjects crossover design to examine whether a 20-minute session of sham-controlled bilateral tDCS to the dorsolateral prefrontal cortex (anode right/cathode left) would transiently modify food cravings and temporal discounting (TD; a measure of choice impulsivity) in 17 healthy women with frequent food cravings. Whether the effects of tDCS on food craving were moderated by individual differences in TD behaviour was also explored. Participants were exposed to food and a film of people eating, and food cravings and TD were assessed before and after active and sham stimulation. Craving for sweet but not savoury foods was reduced following real tDCS. Participants that exhibited more reflective choice behaviour were more susceptible to the anti-craving effects of tDCS than those that displayed more impulsive choice behaviour. No differences were seen in TD or food consumption after real versus sham tDCS. These findings support the efficacy of tDCS in temporarily lowering food cravings and identify the moderating role of TD behaviour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evidence for oxygen vacancy or ferroelectric polarization induced switchable diode and photovoltaic effects in BiFeO3 based thin films

International Nuclear Information System (INIS)

Guo Yiping; Guo Bing; Dong Wen; Li Hua; Liu Hezhou

2013-01-01

The diode and photovoltaic effects of BiFeO 3 and Bi 0.9 Sr 0.1 FeO 3−δ polycrystalline thin films were investigated by poling the films with increased magnitude and alternating direction. It was found that both electromigration of oxygen vacancies and polarization flipping are able to induce switchable diode and photovoltaic effects. For the Bi 0.9 Sr 0.1 FeO 3−δ thin films with high oxygen vacancy concentration, reversibly switchable diode and photovoltaic effects can be observed due to the electromigration of oxygen vacancies under an electric field much lower than its coercive field. However, for the pure BiFeO 3 thin films with lower oxygen vacancy concentration, the reversibly switchable diode and photovoltaic effect is hard to detect until the occurrence of polarization flipping. The switchable diode and photovoltaic effects can be explained well using the concepts of Schottky-like barrier-to-Ohmic contacts resulting from the combination of oxygen vacancies and polarization. The sign of photocurrent could be independent of the direction of polarization when the modulation of the energy band induced by oxygen vacancies is large enough to offset that induced by polarization. The photovoltaic effect induced by the electromigration of oxygen vacancies is unstable due to the diffusion of oxygen vacancies or the recombination of oxygen vacancies with hopping electrons. Our work provides deep insights into the nature of diode and photovoltaic effects in ferroelectric films, and will facilitate the advanced design of switchable devices combining spintronic, electronic, and optical functionalities. (paper)

Switchable and responsive surfaces and materials for biomedical applications

CERN Document Server

Zhang, Johnathan

2015-01-01

Surface modification of biomaterials can ultimately determine whether a material is accepted or rejected from the human body, and a responsive surface can further make the material ""smart"" and ""intelligent"". Switchable and Responsive Surfaces and Materials for Biomedical Applications outlines synthetic and biological materials that are responsive under different stimuli, their surface design and modification techniques, and applicability in regenerative medicine/tissue engineering,  drug delivery, medical devices, and biomedical diagnostics. Part one provides a detailed overview of swit

Transcranial direct current stimulation over multiple days enhances motor performance of a grip task.

Science.gov (United States)

Fan, Julie; Voisin, Julien; Milot, Marie-Hélène; Higgins, Johanne; Boudrias, Marie-Hélène

2017-09-01

Recovery of handgrip is critical after stroke since it is positively related to upper limb function. To boost motor recovery, transcranial direct current stimulation (tDCS) is a promising, non-invasive brain stimulation technique for the rehabilitation of persons with stroke. When applied over the primary motor cortex (M1), tDCS has been shown to modulate neural processes involved in motor learning. However, no studies have looked at the impact of tDCS on the learning of a grip task in both stroke and healthy individuals. To assess the use of tDCS over multiple days to promote motor learning of a grip task using a learning paradigm involving a speed-accuracy tradeoff in healthy individuals. In a double-blinded experiment, 30 right-handed subjects (mean age: 22.1±3.3 years) participated in the study and were randomly assigned to an anodal (n=15) or sham (n=15) stimulation group. First, subjects performed the grip task with their dominant hand while following the pace of a metronome. Afterwards, subjects trained on the task, at their own pace, over 5 consecutive days while receiving sham or anodal tDCS over M1. After training, subjects performed de novo the metronome-assisted task. The change in performance between the pre and post metronome-assisted task was used to assess the impact of the grip task and tDCS on learning. Anodal tDCS over M1 had a significant effect on the speed-accuracy tradeoff function. The anodal tDCS group showed significantly greater improvement in performance (39.28±15.92%) than the sham tDCS group (24.06±16.35%) on the metronome-assisted task, t(28)=2.583, P=0.015 (effect size d=0.94). Anodal tDCS is effective in promoting grip motor learning in healthy individuals. Further studies are warranted to test its potential use for the rehabilitation of fine motor skills in stroke patients. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Differential effects of bifrontal and occipital nerve stimulation on pain and fatigue using transcranial direct current stimulation in fibromyalgia patients.

Science.gov (United States)

To, Wing Ting; James, Evan; Ost, Jan; Hart, John; De Ridder, Dirk; Vanneste, Sven

2017-07-01

Fibromyalgia is a disorder characterized by widespread musculoskeletal pain frequently accompanied by other symptoms such as fatigue. Moderate improvement from pharmacological and non-pharmacological treatments have proposed non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) to the occipital nerve (more specifically the C2 area) or to the dorsolateral prefrontal cortex (DLPFC) as potential treatments. We aimed to explore the effectiveness of repeated sessions of tDCS (eight sessions) targeting the C2 area and DLPFC in reducing fibromyalgia symptoms, more specifically pain and fatigue. Forty-two fibromyalgia patients received either C2 tDCS, DLPFC tDCS or sham procedure (15 C2 tDCS-11 DLPFC tDCS-16 sham). All groups were treated with eight sessions (two times a week for 4 weeks). Our results show that repeated sessions of C2 tDCS significantly improved pain, but not fatigue, in fibromyalgia patients, whereas repeated sessions of DLPFC tDCS significantly improved pain as well as fatigue. This study shows that eight sessions of tDCS targeting the DLPFC have a more general relief in fibromyalgia patients than when targeting the C2 area, suggesting that stimulating different targets with eight sessions of tDCS can lead to benefits on different symptom dimensions of fibromyalgia.

Cathodal Transcranial Direct Current Stimulation Over Left Dorsolateral Prefrontal Cortex Area Promotes Implicit Motor Learning in a Golf Putting Task.

Science.gov (United States)

Zhu, Frank F; Yeung, Andrew Y; Poolton, Jamie M; Lee, Tatia M C; Leung, Gilberto K K; Masters, Rich S W

2015-01-01

Implicit motor learning is characterized by low dependence on working memory and stable performance despite stress, fatigue, or multi-tasking. However, current paradigms for implicit motor learning are based on behavioral interventions that are often task-specific and limited when applied in practice. To investigate whether cathodal transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) area during motor learning suppressed working memory activity and reduced explicit verbal-analytical involvement in movement control, thereby promoting implicit motor learning. Twenty-seven healthy individuals practiced a golf putting task during a Training Phase while receiving either real cathodal tDCS stimulation over the left DLPFC area or sham stimulation. Their performance was assessed during a Test phase on another day. Verbal working memory capacity was assessed before and after the Training Phase, and before the Test Phase. Compared to sham stimulation, real stimulation suppressed verbal working memory activity after the Training Phase, but enhanced golf putting performance during the Training Phase and the Test Phase, especially when participants were required to multi-task. Cathodal tDCS over the left DLPFC may foster implicit motor learning and performance in complex real-life motor tasks that occur during sports, surgery or motor rehabilitation. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of transcranial direct current stimulation of the motor cortex on prefrontal cortex activation during a neuromuscular fatigue task: an fNIRS study.

Science.gov (United States)

Muthalib, Makii; Kan, Benjamin; Nosaka, Kazunori; Perrey, Stephane

2013-01-01

This study investigated whether manipulation of motor cortex excitability by transcranial direct current stimulation (tDCS) modulates neuromuscular fatigue and functional near-infrared spectroscopy (fNIRS)-derived prefrontal cortex (PFC) activation. Fifteen healthy men (27.7 ± 8.4 years) underwent anodal (2 mA, 10 min) and sham (2 mA, first 30 s only) tDCS delivered to the scalp over the right motor cortex. Subjects initially performed a baseline sustained submaximal (30 % maximal voluntary isometric contraction, MVC) isometric contraction task (SSIT) of the left elbow flexors until task failure, which was followed 50 min later by either an anodal or sham treatment condition, then a subsequent posttreatment SSIT. Endurance time (ET), torque integral (TI), and fNIRS-derived contralateral PFC oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentration changes were determined at task failure. Results indicated that during the baseline and posttreatment SSIT, there were no significant differences in TI and ET, and increases in fNIRS-derived PFC activation at task failure were observed similarly regardless of the tDCS conditions. This suggests that the PFC neuronal activation to maintain muscle force production was not modulated by anodal tDCS.

A double-blind, randomized trial of deep repetitive transcranial magnetic stimulation (rTMS) for autism spectrum disorder.

Science.gov (United States)

Enticott, Peter G; Fitzgibbon, Bernadette M; Kennedy, Hayley A; Arnold, Sara L; Elliot, David; Peachey, Amy; Zangen, Abraham; Fitzgerald, Paul B

2014-01-01

Biomedical treatment options for autism spectrum disorder (ASD) are extremely limited. Repetitive transcranial magnetic stimulation (rTMS) is a safe and efficacious technique when targeting specific areas of cortical dysfunction in major depressive disorder, and a similar approach could yield therapeutic benefits in ASD, if applied to relevant cortical regions. The aim of this study was to examine whether deep rTMS to bilateral dorsomedial prefrontal cortex improves social relating in ASD. 28 adults diagnosed with either autistic disorder (high-functioning) or Asperger's disorder completed a prospective, double-blind, randomized, placebo-controlled design with 2 weeks of daily weekday treatment. This involved deep rTMS to bilateral dorsomedial prefrontal cortex (5 Hz, 10-s train duration, 20-s inter-train interval) for 15 min (1500 pulses per session) using a HAUT-Coil. The sham rTMS coil was encased in the same helmet of the active deep rTMS coil, but no effective field was delivered into the brain. Assessments were conducted before, after, and one month following treatment. Participants in the active condition showed a near significant reduction in self-reported social relating symptoms from pre-treatment to one month follow-up, and a significant reduction in social relating symptoms (relative to sham participants) for both post-treatment assessments. Those in the active condition also showed a reduction in self-oriented anxiety during difficult and emotional social situations from pre-treatment to one month follow-up. There were no changes for those in the sham condition. Deep rTMS to bilateral dorsomedial prefrontal cortex yielded a reduction in social relating impairment and socially-related anxiety. Further research in this area should employ extended rTMS protocols that approximate those used in depression in an attempt to replicate and amplify the clinical response. Copyright © 2014 Elsevier Inc. All rights reserved.

Effectiveness of Traditional Chinese Acupuncture versus Sham Acupuncture: a Systematic Review.

Science.gov (United States)

Carlos, Luís; Cruz, Lóris Aparecida Prado da; Leopoldo, Vanessa Cristina; Campos, Fabrício Ribeiro de; Almeida, Ana Maria de; Silveira, Renata Cristina de Campos Pereira

2016-08-15

to identify and synthesize the evidence from randomized clinical trials that tested the effectiveness of traditional Chinese acupuncture in relation to sham acupuncture for the treatment of hot flashes in menopausal women with breast cancer. systematic review guided by the recommendations of the Cochrane Collaboration. Citations were searched in the following databases: MEDLINE via PubMed, Web of Science, CENTRAL, CINAHL, and LILACS. A combination of the following keywords was used: breast neoplasm, acupuncture, acupuncture therapy, acupuncture points, placebos, sham treatment, hot flashes, hot flushes, menopause, climacteric, and vasomotor symptoms. a total of 272 studies were identified, five of which were selected and analyzed. Slight superiority of traditional acupuncture compared with sham acupuncture was observed; however, there were no strong statistical associations. the evidence gathered was not sufficient to affirm the effectiveness of traditional acupuncture compared with sham acupuncture. identificar e sintetizar as evidências oriundas de ensaios clínicos randomizados que testaram a efetividade da acupuntura tradicional chinesa em relação à sham acupuntura para o tratamento dos fogachos em mulheres com câncer de mama no climatério. revisão sistemática guiada pelas recomendações da Colaboração Cochrane. A busca foi realizada nas bases de dados: MEDLINE via PubMed, Web of Science, CENTRAL Cochrane, CINAHL e LILACS. Adotou-se a combinação dos descritores: breast neoplasm, acupuncture, acupuncture therapy, acupuncture points, placebos, sham treatment, hot flashes, hot flushes, menopause, climacteric, vasomotor symptoms. foram identificados 272 estudos, sendo 5 selecionados e analisados. Foi observada discreta superioridade da acupuntura tradicional em relação à sham, entretanto, sem fortes associações estatísticas. as evidências obtidas não foram suficientes para afirmar quanto à efetividade da acupuntura tradicional em relação �

Dataset of acute repeated sessions of bifrontal transcranial direct current stimulation for treatment of intractable tinnitus: A randomized controlled trial

Directory of Open Access Journals (Sweden)

Ali Yadollahpour

2017-12-01

Full Text Available Transcranial direct current stimulation (tDCS has reportedly shown promising therapeutic effects for tinnitus (Forogh et al., 2016; Joos et al., 2014 [1,2]. Studies are ongoing to determine optimum treatment protocol and the site of stimulation. Findings of the early studies are heterogeneous and most studies have focused on single session tDCS and short follow-up periods. There is no study on repeated sessions of tDCS with long term follow-up. This study presents the results of a randomized clinical trial investigating the therapeutic effects of acute multi-session tDCS over dorsolateral prefrontal cortex (DLPFC on tinnitus symptoms and comorbid depression and anxiety in patients with chronic intractable tinnitus. The dataset includes the demographic information, audiometric assessments, tinnitus specific characteristics, and the response variables of the study. The response variables included the scores of tinnitus handicap inventory (THI, tinnitus loudness and tinnitus related distress based on 0–10 numerical visual analogue scale (VAS scores, beck depression inventory (BDI-II and beck anxiety inventory (BAI scores. The dataset included the scores of THI pre and immediately post intervention, and at one month follow-up; the tinnitus loudness and distress scores prior to intervention, and immediately, one hour, one week, and at one month after the last stimulation session. In addition, the BDI-II, and BAI scores pre and post intervention are included. The data of the real (n=25 and sham tDCS (n=17 groups are reported. The main manuscript of this dataset is 'Acute repeated sessions of bifrontal transcranial direct current stimulation for treatment of intractable tinnitus: a randomized controlled trial' (Bayat et al., submitted for publication [3]. Keywords: Transcranial direct current stimulation, Acute stimulations, Tinnitus, Depression, Anxiety, DLPFC

Effects of a common transcranial direct current stimulation (tDCS) protocol on motor evoked potentials found to be highly variable within individuals over 9 testing sessions.

Science.gov (United States)

Horvath, Jared Cooney; Vogrin, Simon J; Carter, Olivia; Cook, Mark J; Forte, Jason D

2016-09-01

Transcranial direct current stimulation (tDCS) uses a weak electric current to modulate neuronal activity. A neurophysiologic outcome measure to demonstrate reliable tDCS modulation at the group level is transcranial magnetic stimulation engendered motor evoked potentials (MEPs). Here, we conduct a study testing the reliability of individual MEP response patterns following a common tDCS protocol. Fourteen participants (7m/7f) each underwent nine randomized sessions of 1 mA, 10 min tDCS (3 anode; 3 cathode; 3 sham) delivered using an M1/orbito-frontal electrode montage (sessions separated by an average of ~5.5 days). Fifteen MEPs were obtained prior to, immediately following and in 5 min intervals for 30 min following tDCS. TMS was delivered at 130 % resting motor threshold using neuronavigation to ensure consistent coil localization. A number of non-experimental variables were collected during each session. At the individual level, considerable variability was seen among different testing sessions. No participant demonstrated an excitatory response ≥20 % to all three anodal sessions, and no participant demonstrated an inhibitory response ≥20 % to all three cathodal sessions. Intra-class correlation revealed poor anodal and cathodal test-retest reliability [anode: ICC(2,1) = 0.062; cathode: ICC(2,1) = 0.055] and moderate sham test-retest reliability [ICC(2,1) = 0.433]. Results also revealed no significant effect of tDCS at the group level. Using this common protocol, we found the effects of tDCS on MEP amplitudes to be highly variable at the individual level. In addition, no significant effects of tDCS on MEP amplitude were found at the group level. Future studies should consider utilizing a more strict experimental protocol to potentially account for intra-individual response variations.

Vagal activation by sham feeding improves gastric motility in functional dyspepsia.

Science.gov (United States)

Lunding, J A; Nordström, L M; Haukelid, A-O; Gilja, O H; Berstad, A; Hausken, T

2008-06-01

Antral hypomotility and impaired gastric accommodation in patients with functional dyspepsia have been ascribed to vagal dysfunction. We investigated whether vagal stimulation by sham feeding would improve meal-induced gastric motor function in these patients. Fourteen healthy volunteers and 14 functional dyspepsia patients underwent a drink test twice, once with and once without simultaneous sham feeding. After ingesting 500 mL clear meat soup (20 kcal, 37 degrees C) in 4 min, sham feeding was performed for 10 min by chewing a sugar-containing chewing gum while spitting out saliva. Using two- and three-dimensional ultrasound, antral motility index (contraction amplitude x frequency) and intragastric volumes were estimated. Without sham feeding, functional dyspepsia patients had lower motility index than healthy volunteers (area under curve 8.0 +/- 1.2 vs 4.4 +/- 1.0 min(-1), P = 0.04). In functional dyspepsia patients, but not in healthy volunteers, motility index increased and intragastric volume tended to increase by sham feeding (P = 0.04 and P = 0.06 respectively). The change in motility index was negatively correlated to the change in pain score (r = -0.59, P = 0.007). In functional dyspepsia patients, vagal stimulation by sham feeding improves antral motility in response to a soup meal. The result supports the view that impaired vagal stimulation is implicated in the pathogenesis of gastric motility disturbances in functional dyspepsia.

[Thinking on designation of sham acupuncture in clinical research].

Science.gov (United States)

Pan, Li-Jia; Chen, Bo; Zhao, Xue; Guo, Yi

2014-01-01

Randomized controlled trials (RCT) is the source of the raw data of evidence-based medicine. Blind method is adopted in most of the high-quality RCT. Sham acupuncture is the main form of blinded in acupuncture clinical trial. In order to improve the quality of acupuncture clinical trail, based on the necessity of sham acupuncture in clinical research, the current situation as well as the existing problems of sham acupuncture, suggestions were put forward from the aspects of new way and new designation method which can be adopted as reference, and factors which have to be considered during the process of implementing. Various subjective and objective factors involving in the process of trial should be considered, and used of the current international standards, try to be quantification, and carry out strict quality monitoring.

Comparative study of ipsilesional and contralesional repetitive transcranial magnetic stimulations for acute infarction.

Science.gov (United States)

Watanabe, Kosuke; Kudo, Yosuke; Sugawara, Eriko; Nakamizo, Tomoki; Amari, Kazumitsu; Takahashi, Koji; Tanaka, Osamu; Endo, Miho; Hayakawa, Yuko; Johkura, Ken

2018-01-15

Repetitive transcranial magnetic stimulation (rTMS) is reported to improve chronic post-stoke hemiparesis. However, application of rTMS during the acute phase of post-stroke has not fully been investigated. We investigated the safety and the efficacy of intermittent theta-burst stimulation (iTBS) of the affected motor cortex and 1-Hz stimulation of the unaffected hemisphere during the acute phase in patients with hemiparesis due to capsular infarction. Twenty one patients who met the study criteria were randomly assigned to receive, starting within 7days after stroke onset and for a period of 10days, iTBS of the affected motor cortex hand area (n=8), 1-Hz stimulation of the unaffected motor cortex hand area (n=7), or sham stimulation (n=6). Upper limb motor function was evaluated before rTMS and 12weeks after onset of the stroke. Evaluation was based on the Fugl-Meyer Assessment (FMA), Stroke Impairment Assessment Set (SIAS), Modified Ashworth Scale (MAS), grip strength, and motor evoked potential (MEP) amplitude in the first dorsal interosseous (FDI) muscle. Both iTBS applied to the affected motor cortex hand area and 1-Hz stimulation applied to the unaffected motor cortex hand area enhanced motor recovery. In comparison to sham stimulation, iTBS increased the SIAS finger-function test score, and 1-Hz stimulation decreased the MAS wrist and finger score. Ipsilesional iTBS and contralesional 1-Hz stimulation applied during the acute phase of stroke have different effects: ipsilesional iTBS improves movement of the affected limb, whereas contralesional 1-Hz stimulation reduces spasticity of the affected limb. Copyright © 2017 Elsevier B.V. All rights reserved.

SHAM beyond clustering: new tests of galaxy–halo abundance matching with galaxy groups

Energy Technology Data Exchange (ETDEWEB)

Hearin, Andrew P.; Zentner, Andrew R.; Berlind, Andreas A.; Newman, Jeffrey A.

2013-05-27

We construct mock catalogs of galaxy groups using subhalo abundance matching (SHAM) and undertake several new tests of the SHAM prescription for the galaxy-dark matter connection. All SHAM models we studied exhibit significant tension with galaxy groups observed in the Sloan Digital Sky Survey (SDSS). The SHAM prediction for the field galaxy luminosity function (LF) is systematically too dim, and the group galaxy LF systematically too bright, regardless of the details of the SHAM prescription. SHAM models connecting r-band luminosity, Mr, to Vacc, the maximum circular velocity of a subhalo at the time of accretion onto the host, faithfully reproduce galaxy group abundance as a function of richness, g(N). However, SHAM models connecting Mr with Vpeak, the peak value of Vmax over the entire merger history of the halo, over-predict galaxy group abundance. Our results suggest that no SHAM model can simultaneously reproduce the observed g(N) and two-point projected galaxy clustering. Nevertheless, we also report a new success of SHAM: an accurate prediction for Phi(m12), the abundance of galaxy groups as a function of magnitude gap m12, defined as the difference between the r-band absolute magnitude of the two brightest group members. We show that it may be possible to use joint measurements of g(N) and Phi(m12) to tightly constrain the details of the SHAM implementation. Additionally, we show that the hypothesis that the luminosity gap is constructed via random draws from a universal LF provides a poor description of the data, contradicting recent claims in the literature. Finally, we test a common assumption of the Conditional Luminosity Function (CLF) formalism, that the satellite LF need only be conditioned by the brightness of the central galaxy. We find this assumption to be well-supported by the observed Phi(m12).

Transcranial Duplex Sonography Predicts Outcome following an Intracerebral Hemorrhage.

Science.gov (United States)

Camps-Renom, P; Méndez, J; Granell, E; Casoni, F; Prats-Sánchez, L; Martínez-Domeño, A; Guisado-Alonso, D; Martí-Fàbregas, J; Delgado-Mederos, R

2017-08-01

Several radiologic features such as hematoma volume are related to poor outcome following an intracerebral hemorrhage and can be measured with transcranial duplex sonography. We sought to determine the prognostic value of transcranial duplex sonography in patients with intracerebral hemorrhage. We conducted a prospective study of patients diagnosed with spontaneous intracerebral hemorrhage. Transcranial duplex sonography examinations were performed within 2 hours of baseline CT, and we recorded the following variables: hematoma volume, midline shift, third ventricle and lateral ventricle diameters, and the pulsatility index in both MCAs. We correlated these data with the CT scans and assessed the prognostic value of the transcranial duplex sonography measurements. We assessed early neurologic deterioration during hospitalization and mortality at 1-month follow-up. We included 35 patients with a mean age of 72.2 ± 12.8 years. Median baseline hematoma volume was 9.85 mL (interquartile range, 2.74-68.29 mL). We found good agreement and excellent correlation between transcranial duplex sonography and CT when measuring hematoma volume ( r = 0.791; P duplex sonography measurements showed that hematoma volume was an independent predictor of early neurologic deterioration (OR, 1.078; 95% CI, 1.023-1.135) and mortality (OR, 1.089; 95% CI, 1.020-1.160). A second regression analysis with CT variables also demonstrated that hematoma volume was associated with early neurologic deterioration and mortality. When we compared the rating operation curves of both models, their predictive power was similar. Transcranial duplex sonography showed an excellent correlation with CT in assessing hematoma volume and midline shift in patients with intracerebral hemorrhage. Hematoma volume measured with transcranial duplex sonography was an independent predictor of poor outcome. © 2017 by American Journal of Neuroradiology.

A multilevel correction adaptive finite element method for Kohn-Sham equation

Science.gov (United States)

Hu, Guanghui; Xie, Hehu; Xu, Fei

2018-02-01

In this paper, an adaptive finite element method is proposed for solving Kohn-Sham equation with the multilevel correction technique. In the method, the Kohn-Sham equation is solved on a fixed and appropriately coarse mesh with the finite element method in which the finite element space is kept improving by solving the derived boundary value problems on a series of adaptively and successively refined meshes. A main feature of the method is that solving large scale Kohn-Sham system is avoided effectively, and solving the derived boundary value problems can be handled efficiently by classical methods such as the multigrid method. Hence, the significant acceleration can be obtained on solving Kohn-Sham equation with the proposed multilevel correction technique. The performance of the method is examined by a variety of numerical experiments.

Switchable photovoltaic windows enabled by reversible photothermal complex dissociation from methylammonium lead iodide.

Science.gov (United States)

Wheeler, Lance M; Moore, David T; Ihly, Rachelle; Stanton, Noah J; Miller, Elisa M; Tenent, Robert C; Blackburn, Jeffrey L; Neale, Nathan R

2017-11-23

Materials with switchable absorption properties have been widely used for smart window applications to reduce energy consumption and enhance occupant comfort in buildings. In this work, we combine the benefits of smart windows with energy conversion by producing a photovoltaic device with a switchable absorber layer that dynamically responds to sunlight. Upon illumination, photothermal heating switches the absorber layer-composed of a metal halide perovskite-methylamine complex-from a transparent state (68% visible transmittance) to an absorbing, photovoltaic colored state (less than 3% visible transmittance) due to dissociation of methylamine. After cooling, the methylamine complex is re-formed, returning the absorber layer to the transparent state in which the device acts as a window to visible light. The thermodynamics of switching and performance of the device are described. This work validates a photovoltaic window technology that circumvents the fundamental tradeoff between efficient solar conversion and high visible light transmittance that limits conventional semitransparent PV window designs.

Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals.

Science.gov (United States)

Tercjak, Agnieszka; Gutierrez, Junkal; Ocando, Connie; Mondragon, Iñaki

2010-03-16

Conductive properties of different thermosetting materials modified with nematic 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) liquid crystal and rutile TiO(2) nanoparticles were successfully studied by means of tunneling atomic force miscroscopy (TUNA). Taking into account the liquid crystal state of the HBC at room temperature, depending on both the HBC content and the presence of TiO(2) nanoparticles, designed materials showed different TUNA currents passed through the sample. The addition of TiO(2) nanoparticles into the systems multiply the detected current if compared to the thermosetting systems without TiO(2) nanoparticles and simultaneously stabilized the current passed through the sample, making the process reversible since the absolute current values were almost the same applying both negative and positive voltage. Moreover, thermosetting systems modified with liquid crystals with and without TiO(2) nanoparticles are photoluminescence switchable materials as a function of temperature gradient during repeatable heating/cooling cycle. Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals can allow them to find potential application in the field of photoresponsive devices, with a high contrast ratio between transparent and opaque states.

Combined motor point associative stimulation (MPAS) and transcranial direct current stimulation (tDCS) improves plateaued manual dexterity performance.

Science.gov (United States)

Hoseini, Najmeh; Munoz-Rubke, Felipe; Wan, Hsuan-Yu; Block, Hannah J

2016-10-28

Motor point associative stimulation (MPAS) in hand muscles is known to modify motor cortex excitability and improve learning rate, but not plateau of performance, in manual dexterity tasks. Central stimulation of motor cortex, such as transcranial direct current stimulation (tDCS), can have similar effects if accompanied by motor practice, which can be difficult and tiring for patients. Here we asked whether adding tDCS to MPAS could improve manual dexterity in healthy individuals who are already performing at their plateau, with no motor practice during stimulation. We hypothesized that MPAS could provide enough coordinated muscle activity to make motor practice unnecessary, and that this combination of stimulation techniques could yield improvements even in subjects at or near their peak. If so, this approach could have a substantial effect on patients with impaired dexterity, who are far from their peak. MPAS was applied for 30min to two right hand muscles important for manual dexterity. tDCS was simultaneously applied over left sensorimotor cortex. The motor cortex input/output (I/O) curve was assessed with transcranial magnetic stimulation (TMS), and manual dexterity was assessed with the Purdue Pegboard Test. Compared to sham or cathodal tDCS combined with MPAS, anodal tDCS combined with MPAS significantly increased the plateau of manual dexterity. This result suggests that MPAS has the potential to substitute for motor practice in mediating a beneficial effect of tDCS on manual dexterity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effects of anodal transcranial direct current stimulation combined with virtual reality for improving gait in children with spastic diparetic cerebral palsy: a pilot, randomized, controlled, double-blind, clinical trial.

Science.gov (United States)

Collange Grecco, Luanda André; de Almeida Carvalho Duarte, Natália; Mendonça, Mariana E; Galli, Manuela; Fregni, Felipe; Oliveira, Claudia Santos

2015-12-01

To compare the effects of anodal vs. sham transcranial direct current stimulation combined with virtual reality training for improving gait in children with cerebral palsy. A pilot, randomized, controlled, double-blind, clinical trial. Rehabilitation clinics. A total of 20 children with diparesis owing to cerebral palsy. The experimental group received anodal stimulation and the control group received sham stimulation over the primary motor cortex during virtual reality training. All patients underwent the same training programme involving a virtual reality (10 sessions). Evaluations were performed before and after the intervention as well as at the one-month follow-up and involved gait analysis, the Gross Motor Function Measure, the Pediatric Evaluation Disability Inventory and the determination of motor evoked potentials. The experimental group had a better performance regarding gait velocity (experimental group: 0.63 ±0.17 to 0.85 ±0.11 m/s; control group: 0.73 ±0.15 to 0.61 ±0.15 m/s), cadence (experimental group: 97.4 ±14.1 to 116.8 ±8.7 steps/minute; control group: 92.6 ±10.4 to 99.7 ±9.7 steps/minute), gross motor function (dimension D experimental group: 59.7 ±12.8 to 74.9 ±13.8; control group: 58.9 ±10.4 to 69.4 ±9.3; dimension E experimental group: 59.0 ±10.9 to 79.1 ±8.5; control group: 60.3 ±10.1 to 67.4 ±11.4) and independent mobility (experimental group: 34.3 ±5.9 to 43.8 ±75.3; control group: 34.4 ±8.3 to 37.7 ±7.7). Moreover, transcranial direct current stimulation led to a significant increase in motor evoked potential (experimental group: 1.4 ±0.7 to 2.6 ±0.4; control group: 1.3 ±0.6 to 1.6 ±0.4). These preliminary findings support the hypothesis that anodal transcranial direct current stimulation combined with virtual reality training could be a useful tool for improving gait in children with cerebral palsy. © The Author(s) 2015.

Action-blindsight in healthy subjects after transcranial magnetic stimulation

DEFF Research Database (Denmark)

Christensen, Mark Schram; Kristiansen, Lasse; Rowe, James B.

2008-01-01

Clinical cases of blindsight have shown that visually guided movements can be accomplished without conscious visual perception. Here, we show that blindsight can be induced in healthy subjects by using transcranial magnetic stimulation over the visual cortex. Transcranial magnetic stimulation...

A clinical repetitive transcranial magnetic stimulation service in Australia: 6 years on.

Science.gov (United States)

Galletly, Cherrie A; Clarke, Patrick; Carnell, Benjamin L; Gill, Shane

2015-11-01

There is considerable research evidence for the effectiveness of repetitive transcranial magnetic stimulation in the treatment of depression. However, there is little information about its acceptability and outcomes in clinical settings. This naturalistic study reports on a clinical repetitive transcranial magnetic stimulation service that has been running in Adelaide, South Australia (SA), for 6 years. During this time, 214 complete acute courses were provided to patients with treatment-resistant Major Depressive Disorder. Patients received either sequential bilateral or right unilateral repetitive transcranial magnetic stimulation treatment involving either 18 or 20 sessions given over 6 or 4 weeks respectively. Data included patient demographic details, duration of depression, and medication at the beginning of their repetitive transcranial magnetic stimulation course. The Hamilton Depression Rating Scale was used to assess response to repetitive transcranial magnetic stimulation. Of those undergoing a first-time acute treatment course of repetitive transcranial magnetic stimulation (N = 167), 28% achieved remission, while a further 12% met the criteria for a response to treatment. Most patients (N = 123, 77%) had previously been treated with five or more antidepressant medications, and 77 (47%) had previously received electroconvulsive therapy. Referral rates remained high over the 6 years, indicating acceptance of the treatment by referring psychiatrists. There were no significant adverse events, and the treatment was generally well tolerated. In all, 41 patients (25%) had a second course of repetitive transcranial magnetic stimulation and 6 (4%) patients had a third course; 21 patients subsequently received maintenance repetitive transcranial magnetic stimulation. This naturalistic study showed that repetitive transcranial magnetic stimulation was well accepted by both psychiatrists and patients, and has good efficacy and safety. Furthermore

The Effect of Cerebellar Transcranial Direct Current Stimulation on A Throwing Task Depends on Individual Level of Task Performance.

Science.gov (United States)

Mizuguchi, Nobuaki; Katayama, Takashi; Kanosue, Kazuyuki

2018-02-10

The effect of cerebellar transcranial direct current stimulation (tDCS) on motor performance remains controversial. Some studies suggest that the effect of tDCS depends upon task-difficulty and individual level of task performance. Here, we investigated whether the effect of cerebellar tDCS on the motor performance depends upon the individual's level of performance. Twenty-four naïve participants practiced dart throwing while receiving a 2-mA cerebellar tDCS for 20 min under three stimulus conditions (anodal-, cathodal-, and sham-tDCS) on separate days with a double-blind, counter-balanced cross-over design. Task performance was assessed by measuring the distance between the center of the bull's eye and the dart's position. Although task performance tended to improve throughout the practice under all stimulus conditions, improvement within a given day was not significant as compared to the first no-stimulus block. In addition, improvement did not differ among stimulation conditions. However, the magnitude of improvement was associated with an individual's level of task performance only under cathodal tDCS condition (p performance improvement only for the sub-group of participants with lower performance levels as compared to that with sham-tDCS (p task performance. Thus, cerebellar tDCS would facilitate learning of a complex motor skill task only in a subset of individuals. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Transcranial Electrical Stimulation over Dorsolateral Prefrontal Cortex Modulates Processing of Social Cognitive and Affective Information.

Directory of Open Access Journals (Sweden)

Massimiliano Conson

Full Text Available Recent neurofunctional studies suggested that lateral prefrontal cortex is a domain-general cognitive control area modulating computation of social information. Neuropsychological evidence reported dissociations between cognitive and affective components of social cognition. Here, we tested whether performance on social cognitive and affective tasks can be modulated by transcranial direct current stimulation (tDCS over dorsolateral prefrontal cortex (DLPFC. To this aim, we compared the effects of tDCS on explicit recognition of emotional facial expressions (affective task, and on one cognitive task assessing the ability to adopt another person's visual perspective. In a randomized, cross-over design, male and female healthy participants performed the two experimental tasks after bi-hemispheric tDCS (sham, left anodal/right cathodal, and right anodal/left cathodal applied over DLPFC. Results showed that only in male participants explicit recognition of fearful facial expressions was significantly faster after anodal right/cathodal left stimulation with respect to anodal left/cathodal right and sham stimulations. In the visual perspective taking task, instead, anodal right/cathodal left stimulation negatively affected both male and female participants' tendency to adopt another's point of view. These findings demonstrated that concurrent facilitation of right and inhibition of left lateral prefrontal cortex can speed-up males' responses to threatening faces whereas it interferes with the ability to adopt another's viewpoint independently from gender. Thus, stimulation of cognitive control areas can lead to different effects on social cognitive skills depending on the affective vs. cognitive nature of the task, and on the gender-related differences in neural organization of emotion processing.

Physical interpretation and evaluation of the Kohn-Sham and Dyson components of the epsilon-I relations between the Kohn-Sham orbital energies and the ionization potentials

NARCIS (Netherlands)

Gritsenko, O.V.; Braida, B.; Baerends, E.J.

2003-01-01

Theoretical and numerical insight was gained into the relations between the Kohn-Sham orbital energies and relaxed vertical ionization potentials. A connection was made between the Kohn-Sham and Dyson one-electron theories. It was established that the energies of the occupied KS orbitals are

Title: Studies on drug switchability showed heterogeneity in methodological approaches: a scoping review.

Science.gov (United States)

Belleudi, Valeria; Trotta, Francesco; Vecchi, Simona; Amato, Laura; Addis, Antonio; Davoli, Marina

2018-05-16

Several drugs share the same therapeutic indication, including those undergoing patent expiration. Concerns on the interchangeability are frequent in clinical practice, challenging the evaluation of switchability through observational research. To conduct a scoping review of observational studies on drug switchability to identify methodological strategies adopted to deal with bias and confounding. We searched PubMed, EMBASE, and Web of Science (updated 1/31/2017) to identify studies evaluating switchability in terms of effectiveness/safety outcomes or compliance. Three reviewers independently screened studies extracting all characteristics. Strategies to address confounding, particularly, previous drug use and switching reasons were considered. All findings were summarized in descriptive analyses. Thirty-two studies, published in the last 10 years, met the inclusion criteria. Epilepsy, cardiovascular and rheumatology were the most frequently represented clinical areas. 75% of the studies reported data on effectiveness/safety outcomes. The most frequent study design was cohort (65.6%) followed by case-control (21.9%) and self-controlled (12.5%). Case-control and case-crossover studies showed homogeneous methodological strategies to deal with bias and confounding. Among cohort studies, the confounding associated with previous drug use was addressed introducing variables in multivariate model (47.3%) or selecting only adherent patients (14.3%). Around 30% of cohort studies did not report reasons for switching. In the remaining 70%, clinical parameters or previous occurrence of outcomes were measured to identify switching connected with lack of effectiveness or adverse events. This study represents a starting point for researchers and administrators who are approaching the investigation and assessment of issues related to interchangeability of drugs. Copyright © 2018. Published by Elsevier Inc.

Neural substrates underlying stimulation-enhanced motor skill learning after stroke.

Science.gov (United States)

Lefebvre, Stéphanie; Dricot, Laurence; Laloux, Patrice; Gradkowski, Wojciech; Desfontaines, Philippe; Evrard, Frédéric; Peeters, André; Jamart, Jacques; Vandermeeren, Yves

2015-01-01

Motor skill learning is one of the key components of motor function recovery after stroke, especially recovery driven by neurorehabilitation. Transcranial direct current stimulation can enhance neurorehabilitation and motor skill learning in stroke patients. However, the neural mechanisms underlying the retention of stimulation-enhanced motor skill learning involving a paretic upper limb have not been resolved. These neural substrates were explored by means of functional magnetic resonance imaging. Nineteen chronic hemiparetic stroke patients participated in a double-blind, cross-over randomized, sham-controlled experiment with two series. Each series consisted of two sessions: (i) an intervention session during which dual transcranial direct current stimulation or sham was applied during motor skill learning with the paretic upper limb; and (ii) an imaging session 1 week later, during which the patients performed the learned motor skill. The motor skill learning task, called the 'circuit game', involves a speed/accuracy trade-off and consists of moving a pointer controlled by a computer mouse along a complex circuit as quickly and accurately as possible. Relative to the sham series, dual transcranial direct current stimulation applied bilaterally over the primary motor cortex during motor skill learning with the paretic upper limb resulted in (i) enhanced online motor skill learning; (ii) enhanced 1-week retention; and (iii) superior transfer of performance improvement to an untrained task. The 1-week retention's enhancement driven by the intervention was associated with a trend towards normalization of the brain activation pattern during performance of the learned motor skill relative to the sham series. A similar trend towards normalization relative to sham was observed during performance of a simple, untrained task without a speed/accuracy constraint, despite a lack of behavioural difference between the dual transcranial direct current stimulation and sham

Metabolic changes of cerebrum by repetitive transcranial magnetic stimulation over lateral cerebellum: a study with FDG PET.

Science.gov (United States)

Cho, Sang Soo; Yoon, Eun Jin; Bang, Sung Ae; Park, Hyun Soo; Kim, Yu Kyeong; Strafella, Antonio P; Kim, Sang Eun

2012-09-01

To better understand the functional role of cerebellum within the large-scale cerebellocerebral neural network, we investigated the changes of neuronal activity elicited by cerebellar repetitive transcranial magnetic stimulation (rTMS) using (18)F-fluorodeoxyglucose (FDG) and positron emission tomography (PET). Twelve right-handed healthy volunteers were studied with brain FDG PET under two conditions: active rTMS of 1 Hz frequency over the left lateral cerebellum and sham stimulation. Compared to the sham condition, active rTMS induced decreased glucose metabolism in the stimulated left lateral cerebellum, the areas known to be involved in voluntary motor movement (supplementary motor area and posterior parietal cortex) in the right cerebral hemisphere, and the areas known to be involved in cognition and emotion (orbitofrontal, medial frontal, and anterior cingulate gyri) in the left cerebral hemisphere. Increased metabolism was found in cognition- and language-related brain regions such as the left inferior frontal gyrus including Broca's area, bilateral superior temporal gyri including Wernicke's area, and bilateral middle temporal gyri. Left cerebellar rTMS also led to increased metabolism in the left cerebellar dentate nucleus and pons. These results demonstrate that rTMS over the left lateral cerebellum modulates not only the target region excitability but also excitability of remote, but interconnected, motor-, language-, cognition-, and emotion-related cerebral regions. They provide further evidence that the cerebellum is involved not only in motor-related functions but also in higher cognitive abilities and emotion through the large-scale cerebellocereberal neural network.

Ferroelectrics: A pathway to switchable surface chemistry and catalysis

Science.gov (United States)

Kakekhani, Arvin; Ismail-Beigi, Sohrab; Altman, Eric I.

2016-08-01

It has been known for more than six decades that ferroelectricity can affect a material's surface physics and chemistry thereby potentially enhancing its catalytic properties. Ferroelectrics are a class of materials with a switchable electrical polarization that can affect surface stoichiometry and electronic structure and thus adsorption energies and modes; e.g., molecular versus dissociative. Therefore, ferroelectrics may be utilized to achieve switchable surface chemistry whereby surface properties are not fixed but can be dynamically controlled by, for example, applying an external electric field or modulating the temperature. Several important examples of applications of ferroelectric and polar materials in photocatalysis and heterogeneous catalysis are discussed. In photocatalysis, the polarization direction can control band bending at water/ferroelectric and ferroelectric/semiconductor interfaces, thereby facilitating charge separation and transfer to the electrolyte and enhancing photocatalytic activity. For gas-surface interactions, available results suggest that using ferroelectrics to support catalytically active transition metals and oxides is another way to enhance catalytic activity. Finally, the possibility of incorporating ferroelectric switching into the catalytic cycle itself is described. In this scenario, a dynamic collaboration of two polarization states can be used to drive reactions that have been historically challenging to achieve on surfaces with fixed chemical properties (e.g., direct NOx decomposition and the selective partial oxidation of methane). These predictions show that dynamic modulation of the polarization can help overcome some of the fundamental limitations on catalytic activity imposed by the Sabatier principle.

Transcranial magnetic stimulation--may be useful as a preoperative screen of motor tract function.

Science.gov (United States)

Galloway, Gloria M; Dias, Brennan R; Brown, Judy L; Henry, Christina M; Brooks, David A; Buggie, Ed W

2013-08-01

Transcranial motor stimulation with noninvasive cortical surface stimulation, using a high-intensity magnetic field referred to as transcranial magnetic stimulation generally, is considered a nonpainful technique. In contrast, transcranial electric stimulation of the motor tracts typically cannot be done in unanesthesized patients. Intraoperative monitoring of motor tract function with transcranial electric stimulation is considered a standard practice in many institutions for patients during surgical procedures in which there is potential risk of motor tract impairment so that the risk of paraplegia or paraparesis can be reduced. Because transcranial electric stimulation cannot be typically done in the outpatient setting, transcranial magnetic stimulation may be able to provide a well-tolerated method for evaluation of the corticospinal motor tracts before surgery. One hundred fifty-five patients aged 5 to 20 years were evaluated preoperatively with single-stimulation nonrepetitive transcranial magnetic stimulation for preoperative assessment. The presence of responses to transcranial magnetic stimulation reliably predicted the presence of responses to transcranial electric stimulation intraoperatively. No complications occurred during the testing, and findings were correlated to the clinical history and used in the setup of the surgical monitoring.

Spelling rehabilitation using transcranial direct current (tDCS in primary progressive aphasia (PPA.

Directory of Open Access Journals (Sweden)

Constantine Frangakis

2014-04-01

Full Text Available Introduction: Spelling impairments are one of the first deficits that occur early in PPA and can usually predict the variant of PPA in which the patient may progress (Sepelyak et al., 2011. PPA is a neurodegenerative disease that affects people relatively early in life (between 55-65 years and therefore it is important to find ways to alleviate the symptoms or impede the degree of degeneration. We present and discuss new data indicating that a neuromodulatory treatment, using transcranial direct current stimulation (tDCS combined with a spelling intervention, shows promise for maintaining or even improving language abilities in PPA. The aim of this research is to determine whether tDCS plus language therapy is more effective than language therapy alone in treating written language deficits in PPA. Methods: Eight PPA participants underwent anodal tDCS or sham plus spelling intervention in a randomized order using a within-subject cross-over design. They were evaluated before, after, and at 2 weeks and 2 months post-intervention. Spelling intervention varied for each participant according to the main spelling deficit: 3 patients had phoneme-to-grapheme conversion (PGC intervention, 2 had lexical intervention and 3 had advanced PGC intervention (combined with written fluency and PGC practice. Four more patients have already finished the first period of stimulations (ether sham or tDCS and all their other sessions and evaluations will be completed in the next couple months. Analyses-Results: We analyzed the existing set of full data using both within-subject analyses (McNemar tests and across-subjects analyses while taking into account carry-over effects. We evaluated therapy effects by the Generalized Estimating Equation approach (Liang & Zeger, 1986. All participants showed improvement in spelling after spelling intervention in trained items (with either sham or tDCS. There was, however, a significant improvement for untrained items only in the t

Modulating the brain at work using noninvasive transcranial stimulation.

Science.gov (United States)

McKinley, R Andy; Bridges, Nathaniel; Walters, Craig M; Nelson, Jeremy

2012-01-02

This paper proposes a shift in the way researchers currently view and use transcranial brain stimulation technologies. From a neuroscience perspective, the standard application of both transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) has been mainly to explore the function of various brain regions. These tools allow for noninvasive and painless modulation of cortical tissue. In the course of studying the function of an area, many studies often report enhanced performance of a task during or following the stimulation. However, little follow-up research is typically done to further explore these effects. Approaching this growing pool of cognitive neuroscience literature with a neuroergonomics mindset (i.e., studying the brain at work), the possibilities of using these stimulation techniques for more than simply investigating the function of cortical areas become evident. In this paper, we discuss how cognitive neuroscience brain stimulation studies may complement neuroergonomics research on human performance optimization. And, through this discussion, we hope to shift the mindset of viewing transcranial stimulation techniques as solely investigatory basic science tools or possible clinical therapeutic devices to viewing transcranial stimulation techniques as interventional tools to be incorporated in applied science research and systems for the augmentation and enhancement of human operator performance. Published by Elsevier Inc.

A feasible repetitive transcranial magnetic stimulation clinical protocol in migraine prevention.

Science.gov (United States)

Zardouz, Shawn; Shi, Lei; Leung, Albert

2016-01-01

This case series was conducted to determine the clinical feasibility of a repetitive transcranial magnetic stimulation protocol for the prevention of migraine (with and without aura). Five patients with migraines underwent five repetitive transcranial magnetic stimulation sessions separated in 1- to 2-week intervals for a period of 2 months at a single tertiary medical center. Repetitive transcranial magnetic stimulation was applied to the left motor cortex with 2000 pulses (20 trains with 1s inter-train interval) delivered per session, at a frequency of 10 Hz and 80% resting motor threshold. Pre- and post-treatment numerical rating pain scales were collected, and percent reductions in intensity, frequency, and duration were generated. An average decrease in 37.8%, 32.1%, and 31.2% were noted in the intensity, frequency, and duration of migraines post-repetitive transcranial magnetic stimulation, respectively. A mean decrease in 1.9±1.0 (numerical rating pain scale ± standard deviation; range: 0.4-2.8) in headache intensity scores was noted after the repetitive transcranial magnetic stimulation sessions. The tested repetitive transcranial magnetic stimulation protocol is a well-tolerated, safe, and effective method for migraine prevention.

Does Transcranial Direct Current Stimulation Combined with Peripheral Electrical Stimulation Have an Additive Effect in the Control of Hip Joint Osteonecrosis Pain Associated with Sickle Cell Disease? A Protocol for a One-Session Double Blind, Block-Randomized Clinical Trial.

Science.gov (United States)

Lopes, Tiago da Silva; Silva, Wellington Dos Santos; Ribeiro, Sânzia B; Figueiredo, Camila A; Campbell, Fernanda Q; Daltro, Gildasio de Cerqueira; Valenzuela, Antônio; Montoya, Pedro; Lucena, Rita de C S; Baptista, Abrahão F

2017-01-01

Chronic pain in Sickle Cell Disease (SCD) is probably related to maladaptive plasticity of brain areas involved in nociceptive processing. Transcranial Direct Current Stimulation (tDCS) and Peripheral Electrical Stimulation (PES) can modulate cortical excitability and help to control chronic pain. Studies have shown that combined use of tDCS and PES has additive effects. However, to date, no study investigated additive effects of these neuromodulatory techniques on chronic pain in patients with SCD. This protocol describes a study aiming to assess whether combined use of tDCS and PES more effectively alleviate pain in patients with SCD compared to single use of each technique. The study consists of a one-session double blind, block-randomized clinical trial (NCT02813629) in which 128 participants with SCD and femoral osteonecrosis will be enrolled. Stepwise procedures will occur on two independent days. On day 1, participants will be screened for eligibility criteria. On day 2, data collection will occur in four stages: sample characterization, baseline assessment, intervention, and post-intervention assessment. These procedures will last ~5 h. Participants will be divided into two groups according to homozygous for S allele (HbSS) ( n = 64) and heterozygous for S and C alleles (HbSC) ( n = 64) genotypes. Participants in each group will be randomly assigned, equally, to one of the following interventions: (1) active tDCS + active PES; (2) active tDCS + sham PES; (3) sham tDCS + active PES; and (4) sham tDCS + sham PES. Active tDCS intervention will consist of 20 min 2 mA anodic stimulation over the primary motor cortex contralateral to the most painful hip. Active PES intervention will consist of 30 min sensory electrical stimulation at 100 Hz over the most painful hip. The main study outcome will be pain intensity, measured by a Visual Analogue Scale. In addition, electroencephalographic power density, cortical maps of the gluteus maximus muscle elicited by

Effectiveness of Traditional Chinese Acupuncture versus Sham Acupuncture: a Systematic Review

Directory of Open Access Journals (Sweden)

Luís Carlos Lopes-Júnior

Full Text Available ABSTRACT Objective: to identify and synthesize the evidence from randomized clinical trials that tested the effectiveness of traditional Chinese acupuncture in relation to sham acupuncture for the treatment of hot flashes in menopausal women with breast cancer. Method: systematic review guided by the recommendations of the Cochrane Collaboration. Citations were searched in the following databases: MEDLINE via PubMed, Web of Science, CENTRAL, CINAHL, and LILACS. A combination of the following keywords was used: breast neoplasm, acupuncture, acupuncture therapy, acupuncture points, placebos, sham treatment, hot flashes, hot flushes, menopause, climacteric, and vasomotor symptoms. Results: a total of 272 studies were identified, five of which were selected and analyzed. Slight superiority of traditional acupuncture compared with sham acupuncture was observed; however, there were no strong statistical associations. Conclusions: the evidence gathered was not sufficient to affirm the effectiveness of traditional acupuncture compared with sham acupuncture.

Real-time measurement of cerebral blood flow during and after repetitive transcranial magnetic stimulation: A near-infrared spectroscopy study.

Science.gov (United States)

Park, Eunhee; Kang, Min Jae; Lee, Ahee; Chang, Won Hyuk; Shin, Yong-Il; Kim, Yun-Hee

2017-07-13

To confirm the interhemispheric modulation induced by low-frequency repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex, real-time regional cerebral blood flow (rCBF) was assessed using functional near-infrared spectroscopy (fNIRS) in the contralateral primary motor cortex (M1) and premotor cortex (PM). Ten right-handed healthy subjects completed two experimental sessions that were randomly arranged for real or sham rTMS session. In the real rTMS session, fNIRS data were acquired from the right M1 and PM area, while the motor hot spot of the left M1 was stimulated with 1Hz rTMS for 1200 pulses with two boosters. In the sham stimulation session, stimulation was delivered with a disconnected coil. During the real rTMS session, the concentration of oxyhemoglobin ([oxy-Hb]) in the right M1 increased continuously until the end of the stimulation. These changes lasted for 20min, while the right PM did not show a change in [oxy-Hb] concentration. On the other hand, the concentration of deoxy-hemoglobin ([deoxy-Hb]) decreased continuously in the right M1 and PM during the real rTMS stimulation, and this change lasted for 20min after the stimulation. The sham stimulation did not exhibit any significant change in both [oxy-Hb] and [deoxy-Hb] concentration during or after the stimulation. Application of 1Hz rTMS over M1 resulted in changes of rCBF in contralateral M1 and PM, which seemed to constitute a function of interhemispheric modulation of rTMS. The fNIRS data was able to detect this physiological change of neuromodulatory action of rTMS in real-time. Copyright © 2017. Published by Elsevier B.V.

Transcranial route of brain targeted delivery of methadone in oil.

Science.gov (United States)

Pathirana, W; Abhayawardhana, P; Kariyawasam, H; Ratnasooriya, W D

2009-05-01

The unique anatomical arrangement of blood vessels and sinuses in the human skull and the brain, the prevalence of a high density of skin appendages in the scalp, extracranial vessels of the scalp communicating with the brain via emissary veins and most importantly, the way that the scalp is used in Ayurvedic medical system in treating diseases associated with the brain show that a drug could be transcranially delivered and targeted to the brain through the scalp. The present study was to investigate by measuring the antinociceptive effect on rats whether the opioid analgesic methadone could be delivered and targeted to the brain by transcranial delivery route. A non aqueous solution of methadone base in sesame oil was used for the application on the scalp. Animal studies were carried out using six groups of male rats consisting of group 1, the oral control treated with distilled water 1 ml; group 2, the oral positive control treated with methadone hydrochloride solution 316.5 mug/ml; group 3, the negative control treated transcranially with the blank sesame oil 0.2 ml and three test groups 4, 5 and 6 treated with three different dose levels of the transcranial oil formulation of methadone base, 41.6 mug/0.2 ml, 104 mug/0.2 ml and 208 mug/0.2 ml, respectively. The antinociceptive effects were examined by subjecting the rats to the hot plate and tail flick tests. The two higher concentrations of the three transcranial methadone formulations yielded response vs time curves showing nearly equal maximum antinociceptive effects similar to that of the oral positive control. Maximum analgesic effect after transcranial administration was observed between 1st and 2nd h and declined up to 6th hour. The results indicate that the transcranial brain targeted delivery of methadone base in the form of an oil based non aqueous solution results in statistically significant antinociceptive effects under experimental conditions. Therefore, it is possible to deliver central nervous

On the physical nature and chemical utility of Kohn-Sham orbitals

International Nuclear Information System (INIS)

Baerends, E.J.

1996-01-01

Density functional calculations almost invariably use the one-electron Kohn-Sham orbitals to calculate the electron density. It is sometimes stated that these KS orbitals have no special physical meaning, but are constructs, arising in the KS formulation of DFT, that are only useful to obtain the density. We will argue that on the contrary the KS orbitals are often very similar to the molecular orbitals that arise in the Hartree-Fock model. When they differ the Kohn-Sham orbitals have certain advantageous properties and correspond in fact more closely to the orbitals used explicitly or implicitly in qualitative MO theory. The arguments of QMO theory, with their emphasis on bonding and antibonding nature of MOs, do hold perfectly for KS orbitals. The reason that Kohn-Sham orbitals are meaningful objects is related to the fact that the effective one-electron Kohn-Sham potential embodies the effects of electron correlation. It has recently become possible to calculate accurate Kohn-Sham potentials from accurate electron densities. This offers the possibility to study the structure of KS potentials (steps, peaks) and to relate this structure to electron correlation. More importantly, given exact Kohn-Sham potentials and orbitals it is possible to construct an exchange-correlation energy density that will, after integration over space, yield the exact exchange-correlation energy. It is possible to relate the local features of the exact energy density to aspects of electron correlation. The exact energy density may be used to judge existing model exchange-correlation energy densities and hopefully it will be helpful to devise improvements

Neuropathic pain: transcranial electric motor cortex stimulation using high frequency random noise. Case report of a novel treatment

Directory of Open Access Journals (Sweden)

Alm PA

2013-06-01

Full Text Available Per A Alm, Karolina DreimanisDepartment of Neuroscience, Uppsala University, Uppsala, SwedenObjectives: Electric motor cortex stimulation has been reported to be effective for many cases of neuropathic pain, in the form of epidural stimulation or transcranial direct current stimulation (tDCS. A novel technique is transcranial random noise stimulation (tRNS, which increases the cortical excitability irrespective of the orientation of the current. The aim of this study was to investigate the effect of tRNS on neuropathic pain in a small number of subjects, and in a case study explore the effects of different stimulation parameters and the long-term stability of treatment effects.Methods: The study was divided into three phases: (1 a double-blind 100–600 Hz, varying from 0.5 to 10 minutes and from 50 to 1500 µA, at intervals ranging from daily to fortnightly.crossover study, with four subjects; (2 a double-blind extended case study with one responder; and (3 open continued treatment. The motor cortex stimulation consisted of alternating current random noise (100–600 Hz, varying from 0.5 to 10 minutes and from 50 to 1500 μA, at intervals ranging from daily to fortnightly.Results: One out of four participants showed a strong positive effect (also compared with direct-current-sham, P = 0.006. Unexpectedly, this effect was shown to occur also for very weak (100 µA, P = 0.048 and brief (0.5 minutes, P = 0.028 stimulation. The effect was largest during the first month, but remained at a highly motivating level for the patient after 6 months.Discussion: The study suggests that tRNS may be an effective treatment for some cases of neuropathic pain. An important result was the indication that even low levels of stimulation may have substantial effects.Keywords: neuropathic pain, central pain, transcranial direct current stimulation, motor cortex stimulation, random noise stimulation

Velocity form of the Kohn-Sham frequency-dependent polarizability equations

International Nuclear Information System (INIS)

Bartolotti, L.J.

1987-01-01

A single equation is derived for the determination of the first-order correction to the frequency-dependent density, due to the perturbation of a time-varying electric field. This new expression for the first-order correction to the frequency-dependent Kohn-Sham amplitudes depends explicitly upon the velocity form of the dipole-moment operator and the square of the Kohn-Sham Hamiltonian

Tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser based on nonlinear polarization rotation

International Nuclear Information System (INIS)

Luo, A-P; Luo, Z-C; Xu, W-C; Dvoyrin, V V; Mashinsky, V M; Dianov, E M

2011-01-01

We demonstrate a tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser by using nonlinear polarization rotation (NPR) technique. Exploiting the spectral filtering effect caused by the combination of the polarizer and intracavity birefringence, the wavelength separation of dual-wavelength mode-locked pulses can be flexibly tuned between 2.38 and 20.45 nm. Taking the advantage of NPR-induced intensity-dependent loss to suppress the mode competition, the stable dual-wavelength pulses output is obtained at room temperature. Moreover, the dual-wavelength switchable operation is achieved by simply rotating the polarization controllers (PCs)

Effects of the addition of transcranial direct current stimulation to virtual reality therapy after stroke: a pilot randomized controlled trial.

Science.gov (United States)

Viana, R T; Laurentino, G E C; Souza, R J P; Fonseca, J B; Silva Filho, E M; Dias, S N; Teixeira-Salmela, L F; Monte-Silva, K K

2014-01-01

Upper limb (UL) impairment is the most common disabling deficit following a stroke. Previous studies have suggested that transcranial direct current stimulation (tDCS) enhances the effect of conventional therapies. This pilot double-blind randomized control trial aimed to determine whether or not tDCS, combined with Wii virtual reality therapy (VRT), would be superior to Wii therapy alone in improving upper limb function and quality of life in chronic stroke individuals. Twenty participants were randomly assigned either to an experimental group that received VRT and tDCS, or a control group that received VRT and sham tDCS. The therapy was delivered over 15 sessions with 13 minutes of active or sham anodal tDCS, and one hour of virtual reality therapy. The outcomes included were determined using the Fugl-Meyer scale, the Wolf motor function test, the modified Ashworth scale (MAS), grip strength, and the stroke specific quality of life scale (SSQOL). Minimal clinically important differences (MCID) were observed when assessing outcome data. Both groups demonstrated gains in all evaluated areas, except for the SSQOL-UL domain. Differences between groups were only observed in wrist spasticity levels in the experimental group, where more than 50% of the participants achieved the MCID. These findings support that tDCS, combined with VRT therapy, should be investigated and clarified further.

Elastic recoil detection analysis for the determination of hydrogen concentration profiles in switchable mirrors

NARCIS (Netherlands)

Huisman, M.C.; van der Molen, S.J.; Vis, R.D.

1999-01-01

Switchable mirrors made of thin films of Y, La or rare-earth (RE) metals exhibit spectacular changes in their optical and electrical properties upon hydrogen loading. The study of these materials has indicated that the occurring phenomena are highly sensitive to the actual hydrogen concentration in

Transcranial direct current stimulation to lessen neuropathic pain after spinal cord injury: a mechanistic PET study.

Science.gov (United States)

Yoon, Eun Jin; Kim, Yu Kyeong; Kim, Hye-Ri; Kim, Sang Eun; Lee, Youngjo; Shin, Hyung Ik

2014-01-01

It is suggested that transcranial direct current stimulation (tDCS) can produce lasting changes in corticospinal excitability and can potentially be used for the treatment of neuropathic pain. However, the detailed mechanisms underlying the effects of tDCS are unknown. We investigated the underlying neural mechanisms of tDCS for chronic pain relief using [(18)F]-fluorodeoxyglucose positron emission tomography ([(18)F]FDG-PET). Sixteen patients with neuropathic pain (mean age 44.1 ± 8.6 years, 4 females) due to traumatic spinal cord injury received sham or active anodal stimulation of the motor cortex using tDCS for 10 days (20 minutes, 2 mA, twice a day). The effect of tDCS on regional cerebral glucose metabolism was evaluated by [(18)F]FDG-PET before and after tDCS sessions. There was a significant decrease in the numeric rating scale scores for pain, from 7.6 ± 0.5 at baseline to 5.9 ± 1.8 after active tDCS (P = .016). We found increased metabolism in the medulla and decreased metabolism in the left dorsolateral prefrontal cortex after active tDCS treatment compared with the changes induced by sham tDCS. Additionally, an increase in metabolism after active tDCS was observed in the subgenual anterior cingulate cortex and insula. The results of this study suggest that anodal stimulation of the motor cortex using tDCS can modulate emotional and cognitive components of pain and normalize excessive attention to pain and pain-related information.

Single Session Low Frequency Left Dorsolateral Prefrontal Transcranial Magnetic Stimulation Changes Neurometabolite Relationships in Healthy Humans

Directory of Open Access Journals (Sweden)

Nathaniel R. Bridges

2018-03-01

Full Text Available Background: Dorsolateral prefrontal cortex (DLPFC low frequency repetitive transcranial magnetic stimulation (LF-rTMS has shown promise as a treatment and investigative tool in the medical and research communities. Researchers have made significant progress elucidating DLPFC LF-rTMS effects—primarily in individuals with psychiatric disorders. However, more efforts investigating underlying molecular changes and establishing links to functional and behavioral outcomes in healthy humans are needed.Objective: We aimed to quantify neuromolecular changes and relate these to functional changes following a single session of DLPFC LF-rTMS in healthy participants.Methods: Eleven participants received sham-controlled neuronavigated 1 Hz rTMS to the region most activated by a 7-letter Sternberg working memory task (SWMT within the left DLPFC. We quantified SWMT performance, functional magnetic resonance activation and proton Magnetic resonance spectroscopy (MRS neurometabolite measure changes before and after stimulation.Results: A single LF-rTMS session was not sufficient to change DLPFC neurometabolite levels and these changes did not correlate with DLPFC activation changes. Real rTMS, however, significantly altered neurometabolite correlations (compared to sham rTMS, both with baseline levels and between the metabolites themselves. Additionally, real rTMS was associated with diminished reaction time (RT performance improvements and increased activation within the motor, somatosensory and lateral occipital cortices.Conclusion: These results show that a single session of LF-rTMS is sufficient to influence metabolite relationships and causes widespread activation in healthy humans. Investigating correlational relationships may provide insight into mechanisms underlying LF-rTMS.

Focused transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex modulates specific domains of self-regulation.

Science.gov (United States)

Pripfl, Jürgen; Lamm, Claus

2015-02-01

Recent neuroscience theories suggest that different kinds of self-regulation may share a common psychobiological mechanism. However, empirical evidence for a domain general self-regulation mechanism is scarce. The aim of this study was to investigate whether focused anodal transcranial direct current stimulation (tDCS), facilitating the activity of the dorsolateral prefrontal cortex (dlPFC), acts on a domain general self-regulation mechanism and thus modulates both affective and appetitive self-regulation. Twenty smokers participated in this within-subject sham controlled study. Effects of anodal left, anodal right and sham tDCS over the dlPFC on affective picture appraisal and nicotine craving-cue appraisal were assessed. Anodal right tDCS over the dlPFC reduced negative affect in emotion appraisal, but neither modulated regulation of positive emotion appraisal nor of craving appraisal. Anodal left stimulation did not induce any significant effects. The results of our study show that domain specific self-regulation networks are at work in the prefrontal cortex. Focused tDCS modulation of this specific self-regulation network could probably be used during the first phase of nicotine abstinence, during which negative affect might easily result in relapse. These findings have implications for neuroscience models of self-regulation and are of relevance for the development of brain stimulation based treatment methods for neuropsychiatric disorders associated with self-regulation deficits. Copyright © 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Bypassing the Kohn-Sham equations with machine learning.

Science.gov (United States)

Brockherde, Felix; Vogt, Leslie; Li, Li; Tuckerman, Mark E; Burke, Kieron; Müller, Klaus-Robert

2017-10-11

Last year, at least 30,000 scientific papers used the Kohn-Sham scheme of density functional theory to solve electronic structure problems in a wide variety of scientific fields. Machine learning holds the promise of learning the energy functional via examples, bypassing the need to solve the Kohn-Sham equations. This should yield substantial savings in computer time, allowing larger systems and/or longer time-scales to be tackled, but attempts to machine-learn this functional have been limited by the need to find its derivative. The present work overcomes this difficulty by directly learning the density-potential and energy-density maps for test systems and various molecules. We perform the first molecular dynamics simulation with a machine-learned density functional on malonaldehyde and are able to capture the intramolecular proton transfer process. Learning density models now allows the construction of accurate density functionals for realistic molecular systems.Machine learning allows electronic structure calculations to access larger system sizes and, in dynamical simulations, longer time scales. Here, the authors perform such a simulation using a machine-learned density functional that avoids direct solution of the Kohn-Sham equations.

Influence of Transcranial Direct Current Stimulation to the Cerebellum on Standing Posture Control

Directory of Open Access Journals (Sweden)

Yasuto Inukai

2016-07-01

Full Text Available Damage to the vestibular cerebellum results in dysfunctional standing posture control. Patients with cerebellum dysfunction have a larger sway in the center of gravity while standing compared with healthy subjects. Transcranial direct current stimulation (tDCS is a noninvasive technique for selectively exciting or inhibiting specific neural structures with potential applications in functional assessment and treatment of neural disorders. However, the specific stimulation parameters for influencing postural control have not been assessed. In this study, we investigated the influence of tDCS when applied over the cerebellum on standing posture control. Sixteen healthy subjects received tDCS (20 min, 2 mA over the scalp 2 cm below the inion. In experiment 1, all 16 subjects received tDCS under three stimulus conditions, Sham, Cathodal, and Anodal, in a random order with the second electrode placed on the forehead. In experiment 2, five subjects received cathodal stimulation only with the second electrode placed over the right buccinator muscle. Center of gravity sway was measured twice for 60 s before and after tDCS in a standing posture with eyes open and legs closed, and average total locus length, locus length per second, rectangular area, and enveloped area were calculated. In experiment 1, total locus length and locus length per second decreased significantly after cathodal stimulation but not after anodal or sham stimulation, while no tDCS condition influenced rectangular or enveloped areas. In experiment 2, cathodal tDCS again significantly reduced total locus length and locus length per second but not rectangular and enveloped areas. The effects of tDCS on postural control are polarity-dependent, likely reflecting the selective excitation or inhibition of cerebellar Purkinje cells. Cathodal tDCS to the cerebellum of healthy subjects can alter body sway (velocity.

A Multi-Addressable Dyad with Switchable CMY Colors for Full-Color Rewritable Papers.

Science.gov (United States)

Qin, Tianyou; Han, Jiaqi; Geng, Yue; Ju, Le; Sheng, Lan; Zhang, Sean Xiao-An

2018-06-23

Reversible multicolor displays on solid media using single molecule pigments have been a long-awaited goal. Herein, a new and simple molecular dyad, which can undergo switchable CMY color changes both in solution and solid substrate upon exposure to light, water/acid, and nucleophiles, is designed and synthesized. The stimuli used in this work can be applied independent of each other, which is beneficial for color changes without mutual interference. As a comparison, the mixtures of the two molecular switching motifs forming the basis of the dyad were also studied. The dyad greatly outperforms the corresponding mixed system with respect to reversible color-switching on the paper substrate. Its potential for full-color rewritable paper with excellent reversibility has been demonstrated. Legible multicolor prints, that is, high color contrast and resolution, good dispersion, excellent reversibility, were achieved using common water-jet and light-based printers. This work provides a very promising approach for further development of full-color switchable molecules, materials and displays. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcranial magnetic stimulation in mild to severe hemiparesis early after stroke: a proof of principle and novel approach to improve motor function

Science.gov (United States)

Anjos, Sarah M.; Saposnik, Gustavo; Mello, Eduardo A.; Nagaya, Erina M.; Santos, Waldyr; Ferreiro, Karina N.; Melo, Eduardo S.; Reis, Felipe I.; Scaff, Milberto; Cohen, Leonardo G.

2016-01-01

Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the unaffected hemisphere can enhance function of the paretic hand in patients with mild motor impairment. Effects of low-frequency rTMS to the contralesional motor cortex at an early stage of mild to severe hemiparesis after stroke are unknown. In this pilot, randomized, double-blind clinical trial we compared the effects of low-frequency rTMS or sham rTMS as add-on therapies to outpatient customary rehabilitation, in 30 patients within 5–45 days after ischemic stroke, and mild to severe hand paresis. The primary feasibility outcome was compliance with the interventions. The primary safety outcome was the proportion of intervention-related adverse events. Performance of the paretic hand in the Jebsen–Taylor test and pinch strength were secondary outcomes. Outcomes were assessed at baseline, after ten sessions of treatment administered over 2 weeks and at 1 month after end of treatment. Baseline clinical features were comparable across groups. For the primary feasibility outcome, compliance with treatment was 100% in the active group and 94% in the sham group. There were no serious intervention-related adverse events. There were significant improvements in performance in the Jebsen–Taylor test (mean, 12.3% 1 month after treatment) and pinch force (mean, 0.5 Newtons) in the active group, but not in the sham group. Low-frequency rTMS to the contralesional motor cortex early after stroke is feasible, safe and potentially effective to improve function of the paretic hand, in patients with mild to severe hemiparesis. These promising results will be valuable to design larger randomized clinical trials. PMID:22173953

Rethinking clinical trials of transcranial direct current stimulation: participant and assessor blinding is inadequate at intensities of 2mA.

Directory of Open Access Journals (Sweden)

Neil E O'Connell

Full Text Available BACKGROUND: Many double-blind clinical trials of transcranial direct current stimulation (tDCS use stimulus intensities of 2 mA despite the fact that blinding has not been formally validated under these conditions. The aim of this study was to test the assumption that sham 2 mA tDCS achieves effective blinding. METHODS: A randomised double blind crossover trial. 100 tDCS-naïve healthy volunteers were incorrectly advised that they there were taking part in a trial of tDCS on word memory. Participants attended for two separate sessions. In each session, they completed a word memory task, then received active or sham tDCS (order randomised at 2 mA stimulation intensity for 20 minutes and then repeated the word memory task. They then judged whether they believed they had received active stimulation and rated their confidence in that judgement. The blinded assessor noted when red marks were observed at the electrode sites post-stimulation. RESULTS: tDCS at 2 mA was not effectively blinded. That is, participants correctly judged the stimulation condition greater than would be expected to by chance at both the first session (kappa level of agreement (κ 0.28, 95% confidence interval (CI 0.09 to 0.47 p=0.005 and the second session (κ=0.77, 95%CI 0.64 to 0.90, p=<0.001 indicating inadequate participant blinding. Redness at the reference electrode site was noticeable following active stimulation more than sham stimulation (session one, κ=0.512, 95%CI 0.363 to 0.66, p<0.001; session two, κ=0.677, 95%CI 0.534 to 0.82 indicating inadequate assessor blinding. CONCLUSIONS: Our results suggest that blinding in studies using tDCS at intensities of 2 mA is inadequate. Positive results from such studies should be interpreted with caution.

Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression in Adult and Youth Populations: A Systematic Literature Review and Meta-Analysis

Science.gov (United States)

Leggett, Laura E.; Soril, Lesley J. J.; Coward, Stephanie; Lorenzetti, Diane L.; MacKean, Gail; Clement, Fiona M.

2015-01-01

Background: Between 30% and 60% of individuals with major depressive disorder will have treatment-resistant depression (TRD): depression that does not subside with pharmaceutical treatment. Repetitive transcranial magnetic stimulation (rTMS) is an emerging treatment for TRD. Objective: To establish the efficacy and optimal protocol for rTMS among adults and youth with TRD. Data Sources: Two systematic reviews were conducted: one to determine the efficacy of rTMS for adults with TRD and another to determine the effectiveness of rTMS for youth with TRD. For adults, MEDLINE, Cochrane Central Register of Controlled Trials, PubMed, EMBASE, PsycINFO, Cochrane Database of Systematic Reviews, and Health Technology Assessment Database were searched from inception until January 10, 2014 with no language restrictions. Terms aimed at capturing the target diagnosis, such as depression and depressive disorder, were combined with terms describing the technology, such as transcranial magnetic stimulation and rTMS. Results were limited to studies involving human participants and designed as a randomized controlled trial. For youth, the search was altered to include youth only (aged 13–25 years) and all study designs. When possible, meta-analysis of response and remission rates was conducted. Study Selection: Seventy-three articles were included in this review: 70 on adult and 3 on youth populations. Results: Meta-analysis comparing rTMS and sham in adults found statistically significant results favoring rTMS for response (RR: 2.35 [95% CI, 1.70–3.25]) and remission (RR: 2.24 [95% CI, 1.53–3.27]). No statistically significant differences were found when comparing high- and low-frequency, unilateral and bilateral, low- and high-intensity rTMS or rTMS and electroconvulsive therapy (ECT). While meta-analysis of results from the youth literature was not possible, the limited evidence base suggests that rTMS may be effective for treating TRD in youth. Conclusions: The evidence

Focal Hemodynamic Responses in the Stimulated Hemisphere During High-Definition Transcranial Direct Current Stimulation.

Science.gov (United States)

Muthalib, Makii; Besson, Pierre; Rothwell, John; Perrey, Stéphane

2017-07-17

High-definition transcranial direct current stimulation (HD-tDCS) using a 4 × 1 electrode montage has been previously shown using modeling and physiological studies to constrain the electric field within the spatial extent of the electrodes. The aim of this proof-of-concept study was to determine if functional near-infrared spectroscopy (fNIRS) neuroimaging can be used to determine a hemodynamic correlate of this 4 × 1 HD-tDCS electric field on the brain. In a three session cross-over study design, 13 healthy males received one sham (2 mA, 30 sec) and two real (HD-tDCS-1 and HD-tDCS-2, 2 mA, 10 min) anodal HD-tDCS targeting the left M1 via a 4 × 1 electrode montage (anode on C3 and 4 return electrodes 3.5 cm from anode). The two real HD-tDCS sessions afforded a within-subject replication of the findings. fNIRS was used to measure changes in brain hemodynamics (oxygenated hemoglobin integral-O 2 Hb int ) during each 10 min session from two regions of interest (ROIs) in the stimulated left hemisphere that corresponded to "within" (L in ) and "outside" (L out ) the spatial extent of the 4 × 1 electrode montage, and two corresponding ROIs (R in and R out ) in the right hemisphere. The ANOVA showed that both real anodal HD-tDCS compared to sham induced a significantly greater O 2 Hb int in the L in than L out ROIs of the stimulated left hemisphere; while there were no significant differences between the real and sham sessions for the right hemisphere ROIs. Intra-class correlation coefficients showed "fair-to-good" reproducibility for the left stimulated hemisphere ROIs. The greater O 2 Hb int "within" than "outside" the spatial extent of the 4 × 1 electrode montage represents a hemodynamic correlate of the electrical field distribution, and thus provides a prospective reliable method to determine the dose of stimulation that is necessary to optimize HD-tDCS parameters in various applications. © 2017 International Neuromodulation Society.

Electronic devices containing switchably conductive silicon oxides as a switching element and methods for production and use thereof

Science.gov (United States)

Tour, James M; Yao, Jun; Natelson, Douglas; Zhong, Lin; He, Tao

2013-11-26

In various embodiments, electronic devices containing switchably conductive silicon oxide as a switching element are described herein. The electronic devices are two-terminal devices containing a first electrical contact and a second electrical contact in which at least one of the first electrical contact or the second electrical contact is deposed on a substrate to define a gap region therebetween. A switching layer containing a switchably conductive silicon oxide resides in the the gap region between the first electical contact and the second electrical contact. The electronic devices exhibit hysteretic current versus voltage properties, enabling their use in switching and memory applications. Methods for configuring, operating and constructing the electronic devices are also presented herein.

Efficient construction of exchange and correlation potentials by inverting the Kohn-Sham equations.

Science.gov (United States)

Kananenka, Alexei A; Kohut, Sviataslau V; Gaiduk, Alex P; Ryabinkin, Ilya G; Staroverov, Viktor N

2013-08-21

Given a set of canonical Kohn-Sham orbitals, orbital energies, and an external potential for a many-electron system, one can invert the Kohn-Sham equations in a single step to obtain the corresponding exchange-correlation potential, vXC(r). For orbitals and orbital energies that are solutions of the Kohn-Sham equations with a multiplicative vXC(r) this procedure recovers vXC(r) (in the basis set limit), but for eigenfunctions of a non-multiplicative one-electron operator it produces an orbital-averaged potential. In particular, substitution of Hartree-Fock orbitals and eigenvalues into the Kohn-Sham inversion formula is a fast way to compute the Slater potential. In the same way, we efficiently construct orbital-averaged exchange and correlation potentials for hybrid and kinetic-energy-density-dependent functionals. We also show how the Kohn-Sham inversion approach can be used to compute functional derivatives of explicit density functionals and to approximate functional derivatives of orbital-dependent functionals.

Anodal transcranial direct current stimulation to the cerebellum improves handwriting and cyclic drawing kinematics in focal hand dystonia.

Science.gov (United States)

Bradnam, Lynley V; Graetz, Lynton J; McDonnell, Michelle N; Ridding, Michael C

2015-01-01

There is increasing evidence that the cerebellum has a role in the pathophysiology of primary focal hand dystonia and might provide an intervention target for non-invasive brain stimulation to improve function of the affected hand. The primary objective of this study was to determine if cerebellar transcranial direct current stimulation (tDCS) improves handwriting and cyclic drawing kinematics in people with hand dystonia, by reducing cerebellar-brain inhibition (CBI) evoked by transcranial magnetic stimulation (TMS). Eight people with dystonia (5 writer's dystonia, 3 musician's dystonia) and eight age-matched controls completed the study and underwent cerebellar anodal, cathodal and sham tDCS in separate sessions. Dystonia severity was assessed using the Writer's Cramp Rating Scale (WRCS) and the Arm Dystonia Disability Scale (ADDS). The kinematic measures that differentiated the groups were; mean stroke frequency during handwriting and fast cyclic drawing and average pen pressure during light cyclic drawing. TMS measures of cortical excitability were no different between people with FHD and controls. There was a moderate, negative relationship between TMS-evoked CBI at baseline and the WRCS in dystonia. Anodal cerebellar tDCS reduced handwriting mean stroke frequency and average pen pressure, and increased speed and reduced pen pressure during fast cyclic drawing. Kinematic measures were not associated with a decrease in CBI within an individual. In conclusion, cerebellar anodal tDCS appeared to improve kinematics of handwriting and circle drawing tasks; but the underlying neurophysiological mechanism remains uncertain. A study in a larger homogeneous population is needed to further investigate the possible therapeutic benefit of cerebellar tDCS in dystonia.

Restricted open-shell Kohn-Sham theory: N unpaired electrons

International Nuclear Information System (INIS)

Schulte, Marius; Frank, Irmgard

2010-01-01

Graphical abstract: High-spin or low-spin? The lowest-lying states for different multiplicities of iron complexes are described with a combination of restricted open-shell Kohn-Sham theory and Car-Parrinello molecular dynamics. - Abstract: We present an energy expression for restricted open-shell Kohn-Sham theory for N unpaired electrons. It is shown that it is possible to derive an explicit energy expression for all low-spin multiplets of systems that exhibit neither radial nor cylindrical symmetry. The approach was implemented in the CPMD code and tested for iron complexes.

A power-efficient switchable CML driver at 10 Gbps

Science.gov (United States)

Peipei, Chen; Lei, Li; Huihua, Liu

2016-02-01

High static power limits the application of conventional current-mode logic(CML). This paper presents a power-efficient switchable CML driver, which achieves a significant current saving by 75% compared with conventional ones. Implemented in the 130 nm CMOS technology process, the proposed CML driver just occupies an area about 0.003 mm2 and provides a robust differential signal of 1600 mV for 10 Gbps optical line terminal (OLT) with a total current of 10 mA. The peak-to-peak jitter is about 4 ps (0.04TUI) and the offset voltage is 347.2 mV @ 1600 mVPP.

Augmentation of spelling therapy with transcranial direct current stimulation in primary progressive aphasia: Preliminary results and challenges.

Science.gov (United States)

Tsapkini, Kyrana; Frangakis, Constantine; Gomez, Yessenia; Davis, Cameron; Hillis, Argye E

Primary progressive aphasia (PPA) is a neurodegenerative disease that primarily affects language functions and often begins in the fifth or sixth decade of life. The devastating effects on work and family life call for the investigation of treatment alternatives. In this article, we present new data indicating that neuromodulatory treatment, using transcranial direct current stimulation (tDCS) combined with a spelling intervention, shows some promise for maintaining or even improving language, at least temporarily, in PPA. The main aim of the present article is to determine whether tDCS plus spelling intervention is more effective than spelling intervention alone in treating written language in PPA. We also asked whether the effects of tDCS are sustained longer than the effects of spelling intervention alone. We present data from six PPA participants who underwent anodal tDCS or sham plus spelling intervention in a within-subject crossover design. Each stimulation condition lasted 3 weeks or a total of 15 sessions with a 2-month interval in between. Participants were evaluated on treatment tasks as well as on other language and cognitive tasks at 2-week and 2-month follow-up intervals after each stimulation condition. All participants showed improvement in spelling (with sham or tDCS). There was no difference in the treated items between the two conditions. There was, however, consistent and significant improvement for untrained items only in the tDCS plus spelling intervention condition. Furthermore, the improvement lasted longer in the tDCS plus spelling intervention condition compared to sham plus spelling intervention condition. Neuromodulation with tDCS offers promise as a means of augmenting language therapy to improve written language function at least temporarily in PPA. The consistent finding of generalisation of treatment benefits to untreated items and the superior sustainability of treatment effects with tDCS justifies further investigations. However

Time-dependent density functional theory beyond Kohn-Sham Slater determinants.

Science.gov (United States)

Fuks, Johanna I; Nielsen, Søren E B; Ruggenthaler, Michael; Maitra, Neepa T

2016-08-03

When running time-dependent density functional theory (TDDFT) calculations for real-time simulations of non-equilibrium dynamics, the user has a choice of initial Kohn-Sham state, and typically a Slater determinant is used. We explore the impact of this choice on the exchange-correlation potential when the physical system begins in a 50 : 50 superposition of the ground and first-excited state of the system. We investigate the possibility of judiciously choosing a Kohn-Sham initial state that minimizes errors when adiabatic functionals are used. We find that if the Kohn-Sham state is chosen to have a configuration matching the one that dominates the interacting state, this can be achieved for a finite time duration for some but not all such choices. When the Kohn-Sham system does not begin in a Slater determinant, we further argue that the conventional splitting of the exchange-correlation potential into exchange and correlation parts has limited value, and instead propose a decomposition into a "single-particle" contribution that we denote v, and a remainder. The single-particle contribution can be readily computed as an explicit orbital-functional, reduces to exchange in the Slater determinant case, and offers an alternative to the adiabatic approximation as a starting point for TDDFT approximations.

An Electrically Switchable Metal-Organic Framework

Science.gov (United States)

Fernandez, Carlos A.; Martin, Paul C.; Schaef, Todd; Bowden, Mark E.; Thallapally, Praveen K.; Dang, Liem; Xu, Wu; Chen, Xilin; McGrail, B. Peter

2014-08-01

Crystalline metal organic framework (MOF) materials containing interconnected porosity can be chemically modified to promote stimulus-driven (light, magnetic or electric fields) structural transformations that can be used in a number of devices. Innovative research strategies are now focused on understanding the role of chemical bond manipulation to reversibly alter the free volume in such structures of critical importance for electro-catalysis, molecular electronics, energy storage technologies, sensor devices and smart membranes. In this letter, we study the mechanism for which an electrically switchable MOF composed of Cu(TCNQ) (TCNQ = 7,7,8,8-tetracyanoquinodimethane) transitions from a high-resistance state to a conducting state in a reversible fashion by an applied potential. The actual mechanism for this reversible electrical switching is still not understood even though a number of reports are available describing the application of electric-field-induced switching of Cu(TCNQ) in device fabrication.

Analisis Kecenderungan Manhaj Akidah Shaykh Shams al-Din al-Sumatera’i

Directory of Open Access Journals (Sweden)

MOHD HAIDHAR KAMARZAMAN

2016-12-01

Full Text Available Shaykh Shams al-Din al-Sumatera'i is a very great and respected scholar during 16th and 17th century of Acheh. His knowledge in various fields recognized by local and international scholars. He had been a Qadi Malik al-’Adil, a religious leader, who became a referred by communities and country during the reign of the three Sultans of Aceh. He has authored nearly 40 pieces of books related to the theology and sufism. This study focuses on the methods used by Shaykh Shams al-Din al-Sumatera'i in his theological writings. This study found that Shaykh Shams al-Din al-Sumatera'i had used six methods in the such writings.

Exploratory study of once-daily transcranial direct current stimulation (tDCS) as a treatment for auditory hallucinations in schizophrenia.

Science.gov (United States)

Fröhlich, F; Burrello, T N; Mellin, J M; Cordle, A L; Lustenberger, C M; Gilmore, J H; Jarskog, L F

2016-03-01

Auditory hallucinations are resistant to pharmacotherapy in about 25% of adults with schizophrenia. Treatment with noninvasive brain stimulation would provide a welcomed additional tool for the clinical management of auditory hallucinations. A recent study found a significant reduction in auditory hallucinations in people with schizophrenia after five days of twice-daily transcranial direct current stimulation (tDCS) that simultaneously targeted left dorsolateral prefrontal cortex and left temporo-parietal cortex. We hypothesized that once-daily tDCS with stimulation electrodes over left frontal and temporo-parietal areas reduces auditory hallucinations in patients with schizophrenia. We performed a randomized, double-blind, sham-controlled study that evaluated five days of daily tDCS of the same cortical targets in 26 outpatients with schizophrenia and schizoaffective disorder with auditory hallucinations. We found a significant reduction in auditory hallucinations measured by the Auditory Hallucination Rating Scale (F2,50=12.22, PtDCS for treatment of auditory hallucinations and the pronounced response in the sham-treated group in this study contrasts with the previous finding and demonstrates the need for further optimization and evaluation of noninvasive brain stimulation strategies. In particular, higher cumulative doses and higher treatment frequencies of tDCS together with strategies to reduce placebo responses should be investigated. Additionally, consideration of more targeted stimulation to engage specific deficits in temporal organization of brain activity in patients with auditory hallucinations may be warranted. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Effects of transcranial direct current stimulation (tDCS) on cognition, symptoms, and smoking in schizophrenia: A randomized controlled study.

Science.gov (United States)

Smith, Robert C; Boules, Sylvia; Mattiuz, Sanela; Youssef, Mary; Tobe, Russell H; Sershen, Henry; Lajtha, Abel; Nolan, Karen; Amiaz, Revital; Davis, John M

2015-10-01

Schizophrenia is characterized by cognitive deficits which persist after acute symptoms have been treated or resolved. Transcranial direct current stimulation (tDCS) has been reported to improve cognition and reduce smoking craving in healthy subjects but has not been as carefully evaluated in a randomized controlled study for these effects in schizophrenia. We conducted a randomized double-blind, sham-controlled study of the effects of 5 sessions of tDCS (2 milliamps for 20minutes) on cognition, psychiatric symptoms, and smoking and cigarette craving in 37 outpatients with schizophrenia or schizoaffective disorder who were current smokers. Thirty subjects provided evaluable data on the MATRICS Consensus Cognitive Battery (MCCB), with the primary outcome measure, the MCCB Composite score. Active compared to sham tDCS subjects showed significant improvements after the fifth tDCS session in MCCB Composite score (p=0.008) and on the MCCB Working Memory (p=0.002) and Attention-Vigilance (p=0.027) domain scores, with large effect sizes. MCCB Composite and Working Memory domain scores remained significant at Benjamini-Hochberg corrected significance levels (α=0.05). There were no statistically significant effects on secondary outcome measures of psychiatric symptoms (PANSS scores), hallucinations, cigarette craving, or cigarettes smoked. The positive effects of tDCS on cognitive performance suggest a potential efficacious treatment for cognitive deficits in partially recovered chronic schizophrenia outpatients that should be further investigated. Copyright © 2015 Elsevier B.V. All rights reserved.

Repetitive Transcranial Direct Current Stimulation Induced Excitability Changes of Primary Visual Cortex and Visual Learning Effects-A Pilot Study.

Science.gov (United States)

Sczesny-Kaiser, Matthias; Beckhaus, Katharina; Dinse, Hubert R; Schwenkreis, Peter; Tegenthoff, Martin; Höffken, Oliver

2016-01-01

Studies on noninvasive motor cortex stimulation and motor learning demonstrated cortical excitability as a marker for a learning effect. Transcranial direct current stimulation (tDCS) is a non-invasive tool to modulate cortical excitability. It is as yet unknown how tDCS-induced excitability changes and perceptual learning in visual cortex correlate. Our study aimed to examine the influence of tDCS on visual perceptual learning in healthy humans. Additionally, we measured excitability in primary visual cortex (V1). We hypothesized that anodal tDCS would improve and cathodal tDCS would have minor or no effects on visual learning. Anodal, cathodal or sham tDCS were applied over V1 in a randomized, double-blinded design over four consecutive days (n = 30). During 20 min of tDCS, subjects had to learn a visual orientation-discrimination task (ODT). Excitability parameters were measured by analyzing paired-stimulation behavior of visual-evoked potentials (ps-VEP) and by measuring phosphene thresholds (PTs) before and after the stimulation period of 4 days. Compared with sham-tDCS, anodal tDCS led to an improvement of visual discrimination learning (p learning effect. For cathodal tDCS, no significant effects on learning or on excitability could be seen. Our results showed that anodal tDCS over V1 resulted in improved visual perceptual learning and increased cortical excitability. tDCS is a promising tool to alter V1 excitability and, hence, perceptual visual learning.

Perceived Comfort and Blinding Efficacy in Randomised Sham-Controlled Transcranial Direct Current Stimulation (tDCS Trials at 2 mA in Young and Older Healthy Adults.

Directory of Open Access Journals (Sweden)

Denise Wallace

Full Text Available tDCS studies typically find that: lowest levels of comfort occur at stimulation-onset; young adult participants experience less comfort than older participants; and participants' blinding seems effective at low current strengths. At 2 mA conflicting results have been reported, questioning the effectiveness of blinding in sham-controlled paradigms using higher current strengths. Investigator blinding is rarely reported.Using a protocol with 30 min of 2 mA stimulation we sought to: (a investigate the level of perceived comfort in young and older adults, ranging in age from 19 to 29 years and 63 to 76 years, respectively; (b test investigator and participant blinding; (c assess comfort over a longer stimulation duration; (d add to the literature on protocols using 2 mA current strength.A two-session experiment was conducted where sham and active stimulation were administered to the frontal cortex at the F8/FP1 sites in a within-subjects manner. Levels of perceived comfort were measured, using a visual analogue scale, at the start and end of stimulation in young and older adults. Post-stimulation, participants and investigators judged whether or not active stimulation was used.Comfort scores were lower at stimulation onset in both age groups. Older adults reported: (i more comfort than young participants overall; (ii comparable levels of comfort in sham and active stimulation; (iii significantly more comfort than the young participants during active stimulation. Stimulation mode was correctly identified above chance in the second of the two sessions; 65% of all participants correctly identified the stimulation mode, resulting in a statistical trend. Similarly, the experimenter correctly identified stimulation mode significantly above chance, with 62% of all investigator judgements correct across 120 judgements.Using 2 mA current strength over 30 minutes, tDCS stimulation comfort is lower at stimulation onset in young and older adults and, overall

Magnetic Resonance Imaging Study Using True versus Sham Acupuncture

Directory of Open Access Journals (Sweden)

Chunxiao Wu

2014-01-01

Full Text Available Functional magnetic resonance imaging (fMRI has been shown to detect the specificity of acupuncture points, as proved by numerous studies. In this study, resting-state fMRI was used to observe brain areas activated by acupuncture at the Taichong (LR3 acupoint. A total of 15 healthy subjects received brain resting-state fMRI before acupuncture and after sham and true acupuncture, respectively, at LR3. Image data processing was performed using Data Processing Assistant for Resting-State fMRI and REST software. The combination of amplitude of low-frequency fluctuation (ALFF and regional homogeneity (ReHo was used to analyze the changes in brain function during sham and true acupuncture. Acupuncture at LR3 can specifically activate or deactivate brain areas related to vision, movement, sensation, emotion, and analgesia. The specific alterations in the anterior cingulate gyrus, thalamus, and cerebellar posterior lobe have a crucial effect and provide a valuable reference. Sham acupuncture has a certain effect on psychological processes and does not affect brain areas related to function.

Photo-switchable two-dimensional nanofluidic ionic diodes.

Science.gov (United States)

Wang, Lili; Feng, Yaping; Zhou, Yi; Jia, Meijuan; Wang, Guojie; Guo, Wei; Jiang, Lei

2017-06-01

The bottom-up assembly of ion-channel-mimetic nanofluidic devices and materials with two-dimensional (2D) nano-building blocks paves a straightforward way towards the real-world applications of the novel transport phenomena on a nano- or sub-nanoscale. One immediate challenge is to provide the 2D nanofluidic systems with adaptive responsibilities and asymmetric ion transport characteristics. Herein, we introduce a facile and general strategy to provide a graphene-oxide-based 2D nanofluidic system with photo-switchable ionic current rectification (ICR). The degree of ICR can be prominently enhanced upon UV irradiation and it can be perfectly retrieved under irradiation with visible light. A maximum ICR ratio of about 48 was achieved. The smart and functional nanofluidic devices have applications in energy conversion, chemical sensing, water treatment, etc .

Stimulating cognition in schizophrenia: A controlled pilot study of the effects of prefrontal transcranial direct current stimulation upon memory and learning.

Science.gov (United States)

Orlov, Natasza D; Tracy, Derek K; Joyce, Daniel; Patel, Shinal; Rodzinka-Pasko, Joanna; Dolan, Hayley; Hodsoll, John; Collier, Tracy; Rothwell, John; Shergill, Sukhwinder S

Schizophrenia is characterized by prominent cognitive deficits, impacting on memory and learning; these are strongly associated with the prefrontal cortex. To combine two interventions, transcranial direct current stimulation (tDCS) over the prefrontal cortex and cognitive training, to examine change in cognitive performance in patients with schizophrenia. A double blind, sham-controlled pilot study of 49 patients with schizophrenia, randomized into real or sham tDCS stimulation groups. Subjects participated in 4 days of cognitive training (days 1, 2, 14, 56) with tDCS applied at day-1 and day-14. The primary outcome measure was change in accuracy on working memory and implicit learning tasks from baseline. The secondary outcome measure was the generalization of learning to non-trained task, indexed by the CogState neuropsychological battery. Data analysis was conducted using multilevel modelling and multiple regressions. 24 participants were randomized to real tDCS and 25 to sham. The working memory task demonstrated a significant mean difference in performance in the tDCS treatment group: at day-2 (b = 0.68, CI 0.14-1.21; p = 0.044) and at day-56 (b = 0.71, 0.16-1.26; p = 0.044). There were no significant effects of tDCS on implicit learning. Trend evidence of generalization onto untrained tasks of attention and vigilance task (b = 0.40, 0.43-0.77; p = 0.058) was found. This is the first study to show a significant longer-term effect of tDCS on working memory in schizophrenia. Given the current lack of effective therapies for cognitive deficits, tDCS may offer an important novel approach to modulating brain networks to ameliorate cognitive deficits in schizophrenia. Copyright © 2016 Elsevier Inc. All rights reserved.

The effect of transcranial direct current stimulation of the prefrontal cortex on implicit self-esteem is mediated by rumination after criticism.

Science.gov (United States)

De Raedt, Rudi; Remue, Jonathan; Loeys, Tom; Hooley, Jill M; Baeken, Chris

2017-12-01

It has been proposed that a crucial link between cognitive (i.e., self-schemas) and biological vulnerability is prefrontal control. This is because decreased control leads to impaired ability to inhibit ruminative thinking after the activation of negative self-schemas. However, current evidence is mainly correlational. In the current experimental study we tested whether the effect of neurostimulation of the dorsolateral prefrontal cortex (DLPFC) on self-esteem is mediated by momentary ruminative self-referential thinking (MRST) after the induction of negative self-schemas by criticism. We used a single, sham-controlled crossover session of anodal transcranial Direct Current Stimulation (tDCS) applied to the left DLPFC (cathode over the right supraorbital region) in healthy female individuals. After receiving tDCS/sham stimulation, we measured MRST and exposed the participants to critical audio scripts, followed by another MRST measurement. Subsequently, all participants completed two Implicit Relational Assessment Procedures to implicitly measure actual and ideal self-esteem. Our behavioral data indicated a significant decrease in MRST after real but not sham tDCS. Moreover, although there was no immediate effect of tDCS on implicit self-esteem, an indirect effect was found through double mediation, with the difference in MRST from baseline to after stimulation and from baseline to after criticism as our two mediators. The larger the decrease of criticism induced MRST after real tDCS, the higher the level of actual self-esteem. Our results show that tDCS can influence cognitive processes such as rumination, and subsequently self-esteem, but only after the activation of negative self-schemas. Rumination and negative self-esteem characterize different forms of psychopathology, and these data expand our knowledge of the role of the prefrontal cortex in controlling these self-referential processes, and the mechanisms of action of tDCS. Copyright © 2017 Elsevier Ltd

Switchable Diastereoselectivity in the Fluoride Promoted Vinylogous Mukaiyama-Michael Reaction of 2-Trimethylsilyloxyfuran Catalyzed by Crown Ethers

KAUST Repository

Della Sala, Giorgio

2017-05-31

The fluoride promoted vinylogous Mukaiyama-Michael reaction (VMMR) of 2-trimethylsilyloxyfuran with diverse α,β-unsaturated ketones is described. The TBAF catalyzed VMMR afforded high anti-diastereoselectivity irrespective of the solvents used. The KF/crown ethers catalytic systems proved to be highly efficient in terms of yields and resulted in a highly diastereoselective unprecedented solvent/catalyst switchable reaction. Anti-adducts were obtained as single diastereomers or with excellent diastereoselectivities when benzo-15-crown-5 in CH2Cl2 was employed. On the other hand, high syn-diastereoselectivities (from 76:24 to 96:4) were achieved by employing dicyclohexane-18-crown-6 in toluene. Based on DFT calculations, the catalysts/solvents-dependent switchable diastereoselectivities are proposed to be the result of loose or tight cation-dienolate ion pairs.

Cerebellar transcranial direct current stimulation modulates verbal working memory.

Science.gov (United States)

Boehringer, Andreas; Macher, Katja; Dukart, Juergen; Villringer, Arno; Pleger, Burkhard

2013-07-01

Neuroimaging studies show cerebellar activations in a wide range of cognitive tasks and patients with cerebellar lesions often present cognitive deficits suggesting a cerebellar role in higher-order cognition. We used cathodal transcranial direct current stimulation (tDCS), known to inhibit neuronal excitability, over the cerebellum to investigate if cathodal tDCS impairs verbal working memory, an important higher-order cognitive faculty. We tested verbal working memory as measured by forward and backward digit spans in 40 healthy young participants before and after applying cathodal tDCS (2 mA, stimulation duration 25 min) to the right cerebellum using a randomized, sham-controlled, double-blind, cross-over design. In addition, we tested the effect of cerebellar tDCS on word reading, finger tapping and a visually cued sensorimotor task. In line with lower digit spans in patients with cerebellar lesions, cerebellar tDCS reduced forward digit spans and blocked the practice dependent increase in backward digit spans. No effects of tDCS on word reading, finger tapping or the visually cued sensorimotor task were found. Our results support the view that the cerebellum contributes to verbal working memory as measured by forward and backward digit spans. Moreover, the induction of reversible "virtual cerebellar lesions" in healthy individuals by means of tDCS may improve our understanding of the mechanistic basis of verbal working memory deficits in patients with cerebellar lesions. Copyright © 2013 Elsevier Inc. All rights reserved.

The effectiveness of foot reflexology in inducing ovulation: a sham-controlled randomized trial.

Science.gov (United States)

Holt, Jane; Lord, Jonathan; Acharya, Umesh; White, Adrian; O'Neill, Nyree; Shaw, Steve; Barton, Andy

2009-06-01

To determine whether foot reflexology, a complementary therapy, has an effect greater than sham reflexology on induction of ovulation. Sham-controlled randomized trial with patients and statistician blinded. Infertility clinic in Plymouth, United Kingdom. Forty-eight women attending the clinic with anovulation. Women were randomized to receive eight sessions of either genuine foot reflexology or sham reflexology with gentle massage over 10 weeks. The primary outcome was ovulation detected by serum progesterone level of >30 nmol/L during the study period. Twenty-six patients were randomized to genuine reflexology and 22 to sham (one randomized patient was withdrawn). Patients remained blinded throughout the trial. The rate of ovulation during true reflexology was 11 out of 26 (42%), and during sham reflexology it was 10 out of 22 (46%). Pregnancy rates were 4 out of 26 in the true group and 2 out of 22 in the control group. Because of recruitment difficulties, the required sample size of 104 women was not achieved. Patient blinding of reflexology studies is feasible. Although this study was too small to reach a definitive conclusion on the specific effect of foot reflexology, the results suggest that any effect on ovulation would not be clinically relevant. Sham reflexology may have a beneficial general effect, which this study was not designed to detect.

Systems Analysis of Human Visuo-Myoelectric Control Facilitated by Anodal Transcranial Direct Current Stimulation in Healthy Humans

Directory of Open Access Journals (Sweden)

Vinh Kha

2018-04-01

Full Text Available Induction of neuroplasticity by transcranial direct current stimulation (tDCS applied to the primary motor cortex facilitates motor learning of the upper extremities in healthy humans. The impact of tDCS on lower limb functions has not been studied extensively so far. In this study, we applied a system identification approach to investigate the impact of anodal transcranial direct current stimulation of the leg area of the motor cortex via the human visuo-myoelectric controller. The visuo-myoelectric reaching task (VMT involves ballistic muscle contraction after a visual cue. We applied a black box approach using a linear ARX (Auto-regressive with eXogenous input model for a visuomotor myoelectric reaching task. We found that a 20th order finite impulse response (FIR model captured the TARGET (single input—CURSOR (single output dynamics during a VMT. The 20th order FIR model was investigated based on gain/phase margin analysis, which showed a significant (p < 0.01 effect of anodal tDCS on the gain margin of the VMT system. Also, response latency and the corticomuscular coherence (CMC time delay were affected (p < 0.05 by anodal tDCS when compared to sham tDCS. Furthermore, gray box simulation results from a Simplified Spinal-Like Controller (SSLC model demonstrated that the input-output function for motor evoked potentials (MEP played an essential role in increasing muscle activation levels and response time improvement post-tDCS when compared to pre-tDCS baseline performance. This computational approach can be used to simulate the behavior of the neuromuscular controller during VMT to elucidate the effects of adjuvant treatment with tDCS.

Zipper-like magnetic molecularly imprinted microspheres for on/off-switchable recognition and extraction of 17β-estradiol from food samples.

Science.gov (United States)

Zhu, Wenting; Peng, Hailong; Luo, Mei; Yu, Ningxiang; Xiong, Hua; Wang, Ronghui; Li, Yanbin

2018-09-30

Zipper-like on/off-switchable and magnetic molecularly imprinted microspheres (SM-MIMs) were constructed using acrylamide (AAm) and 2-acrylamide-2-methyl propanesulfonic acid (AMPS) as functional monomers for 17β-estradiol (17β-E 2 ) recognition and extraction. The imprinted polymer interactions between poly(AAm) (PAAm) and poly(AMPS) (PAMPS) with on/off-switchable property to temperature, exhibited dissociation at relatively higher temperatures (such as 30 °C) and helped 17β-E 2 enter into imprinted sites, leading to higher binding capability. Conversely, the interpolymer complexes between PAAm and PAMPS formed and blocked 17β-E 2 access to imprinted sites at lower temperature (such as 20 °C). SM-MIMs were used as dispersive solid phase extraction (SPE) adsorbent with HPLC for 17β-E 2 pretreatment and detection in food samples, and low limit detection (2.52 µg L -1 ) and quantification (10.76 µg L -1 ) with higher recovery were obtained. Therefore, SM-MIMs may be a promising adsorbent for 17β-E 2 pretreatment in food samples owing to its advantages of on/off-switchable recognition, eco-friendly elution, and efficient separation. Copyright © 2018. Published by Elsevier Ltd.

Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation: A functional MRI study.

Science.gov (United States)

Kwon, Yong Hyun; Jang, Sung Ho

2012-08-25

We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel counts and blood oxygenation level-dependent signal intensities in the right primary sensorimotor cortex regions were estimated and compared between the two transcranial direct current stimulation conditions. Our results showed that dual-hemispheric transcranial direct current stimulation induced greater cortical activities than single-hemispheric transcranial direct current stimulation. These findings suggest that dual-hemispheric transcranial direct current stimulation may provide more effective cortical stimulation than single-hemispheric transcranial direct current stimulation.

Contralesional repetitive transcranial magnetic stimulation for chronic hemiparesis in subcortical paediatric stroke: a randomised trial.

Science.gov (United States)

Kirton, Adam; Chen, Robert; Friefeld, Sharon; Gunraj, Carolyn; Pontigon, Anne-Marie; Deveber, Gabrielle

2008-06-01

Arterial ischaemic stroke (AIS) can cause disabling hemiparesis in children. We aimed to test whether contralesional, inhibitory repetitive transcranial magnetic stimulation (rTMS) could affect interhemispheric inhibition to improve hand function in chronic subcortical paediatric AIS. Patients were eligible for this parallel, randomised trial if they were in the SickKids Children's Stroke Program and had subcortical AIS more than 2 years previously, had transcallosal sparing, were more than 7 years of age, had hand motor impairment, had no seizures or dyskinesia, and were taking no drugs that alter cortical excitability. Patients were paired for age and weakness and were randomised within each pair to sham treatment or inhibitory, low-frequency rTMS over contralesional motor cortex (20 min, 1200 stimuli) once per day for 8 days. An occupational therapist did standardised tests of hand function at days 1 (baseline), 5, 10, and 17 (1 week post-treatment), and the primary outcomes were changes in grip strength and the Melbourne assessment of upper extremity function (MAUEF) between baseline and day 10. Patients, parents, and occupational therapists were blinded to treatment allocation. Analysis was per protocol. Ten patients with paediatric stroke were enrolled (median age 13.25 [IQR 10.08-16.78] years, mean time post-stroke 6.33 [SD 3.56] years): four with mild weakness, two with moderate weakness, and four with severe weakness. A repeated-measures ANOVA showed a significant interaction between time and the effect of treatment on grip strength (p=0.03). At day 10, grip strength was 2.28 (SD 1.01) kg greater than baseline in the rTMS group and 2.92 (1.20) kg less than baseline in the sham group (p=0.009). Benefits in mean grip strength persisted at day 17 (2.63 [0.56] kg greater than baseline with rTMS and 1.00 [0.70] kg less than baseline with sham treatment; p=0.01). Day 10 MAUEF score improved by more in the rTMS group than in the sham group (7.25 [3.8] vs 0.79 [1

Improving executive function using transcranial infrared laser stimulation.

Science.gov (United States)

Blanco, Nathaniel J; Maddox, W Todd; Gonzalez-Lima, Francisco

2017-03-01

Transcranial infrared laser stimulation is a new non-invasive form of low-level light therapy that may have a wide range of neuropsychological applications. It entails using low-power and high-energy-density infrared light from lasers to increase metabolic energy. Preclinical work showed that this intervention can increase cortical metabolic energy, thereby improving frontal cortex-based memory function in rats. Barrett and Gonzalez-Lima (2013, Neuroscience, 230, 13) discovered that transcranial laser stimulation can enhance sustained attention and short-term memory in humans. We extend this line of work to executive function. Specifically, we ask whether transcranial laser stimulation enhances performance in the Wisconsin Card Sorting Task that is considered the gold standard of executive function and is compromised in normal ageing and a number of neuropsychological disorders. We used a laser of a specific wavelength (1,064 nm) that photostimulates cytochrome oxidase - the enzyme catalysing oxygen consumption for metabolic energy production. Increased cytochrome oxidase activity is considered the primary mechanism of action of this intervention. Participants who received laser treatment made fewer errors and showed improved set-shifting ability relative to placebo controls. These results suggest that transcranial laser stimulation improves executive function and may have exciting potential for treating or preventing deficits resulting from neuropsychological disorders or normal ageing. © 2015 The British Psychological Society.

Transcranial Doppler ultrasound and cerebral angiography - alternative or complementary

International Nuclear Information System (INIS)

Bockenheimer, S.; Lorey, N.

1985-01-01

Transcranial Doppler ultrasound is a noninvasive method of recording the flow velocity of larger intracranial vessels. The impact on diagnosis of cerebravascular occlusive disease is not yet evaluated. We present 15 patients, age range 39-73 years, who suffered from completed stroke. The findings of transcranial Doppler ultrasound and of cerebral angiography are presented. The value of both methods in treatment strategy is discussed. (orig.) [de

Transcranial Direct Current Stimulation in Patients with Prolonged Disorders of Consciousness: Combined Behavioral and Event-Related Potential Evidence

Directory of Open Access Journals (Sweden)

Ye Zhang

2017-11-01

Full Text Available BackgroundThe electrophysiological evidence supporting the therapeutic efficacy of multiple transcranial direct current stimulation (tDCS sessions on consciousness improvement in patients with prolonged disorders of consciousness (DOCs has not been firmly established.ObjectivesTo assess the effects of repeated tDCS in patients with prolonged DOCs by Coma Recovery Scale-Revised (CRS-R score and event-related potential (ERP.MethodUsing a sham-controlled randomized double-blind design, 26 patients were randomly assigned to either a real [five vegetative state (VS and eight minimally conscious state (MCS patients] or sham (six VS and seven MCS patients stimulation group. The patients in the real stimulation group underwent 20 anodal tDCS sessions of the left dorsolateral prefrontal cortex (DLPFC over 10 consecutive working days. The CRS-R score and P300 amplitude and latency in a hierarchical cognitive assessment were recorded to evaluate the consciousness level before tDCS and immediately after the 20 sessions.ResultsThe intra-group CRS-R analysis revealed a clinically significant improvement in the MCS patients in the real stimulation group. The inter-group CRS-R analysis showed a significant difference in CRS-R between VS and MCS patients at baseline in both the real and sham stimulation groups. The intra-group ERP analysis revealed a significant increase in P300 amplitude after tDCS in the MCS patients in the real stimulation group, but no significant differences in P300 latency. For the inter-group ERP analysis, we observed significant differences regarding the presence of P300 at baseline between the VS and MCS patients in both groups.ConclusionThe repeated anodal tDCS of the left DLPFC could produce clinically significant improvements in MCS patients. The observed tDCS-related consciousness improvements might be related to improvements in attention resource allocation (reflected by the P300 amplitude. The findings support the use of tDCS in

Electromagnetic Field Modeling of Transcranial Electric and Magnetic Stimulation: Targeting, Individualization, and Safety of Convulsive and Subconvulsive Applications

Science.gov (United States)

Deng, Zhi-De

inform dosage requirements in convulsive therapies. Our results indicate that the MST electric field is more focal and more confined to the superficial cortex compared to ECT. Further, the conventional ECT current amplitude is much higher than necessary for seizure induction. One of the factors important to clinical outcome is seizure expression. However, it is unknown how the induced electric field is related to seizure onset and propagation. In this work, we explore the effect of the electric field distribution on the quantitative ictal electroencephalography and current source density in ECT and MST. We further demonstrate how the ECT electrode shape, size, spacing, and current can be manipulated to yield more precise control of the induced electric field. If desirable, ECT can be made as focal as MST while using simpler stimulation equipment. Next, we demonstrate how the electric field induced by transcranial magnetic stimulation (TMS) can be controlled. We present the most comprehensive comparison of TMS coil electric field penetration and focality to date. The electric field distributions of more than 50 TMS coils were simulated. We show that TMS coils differ markedly in their electric field characteristics, but they all are subject to a consistent depth-focality tradeoff. Specifically, the ability to directly stimulate deeper brain structures is obtained at the expense of inducing wider electric field spread. Figure-8 type coils are fundamentally more focal compared to circular type coils. Understanding the depth-focality tradeoff can help researchers and clinicians to appropriately select coils and interpret TMS studies. This work also enables the development of novel TMS coils with electronically switchable active and sham modes as well as for deep TMS. Design considerations of these coils are extensively discussed. Part II of the dissertation aims to quantify the effect of individual, sex, and age differences in head geometry and conductivity on the induced

Probing neural mechanisms underlying auditory stream segregation in humans by transcranial direct current stimulation (tDCS).

Science.gov (United States)

Deike, Susann; Deliano, Matthias; Brechmann, André

2016-10-01

One hypothesis concerning the neural underpinnings of auditory streaming states that frequency tuning of tonotopically organized neurons in primary auditory fields in combination with physiological forward suppression is necessary for the separation of representations of high-frequency A and low-frequency B tones. The extent of spatial overlap between the tonotopic activations of A and B tones is thought to underlie the perceptual organization of streaming sequences into one coherent or two separate streams. The present study attempts to interfere with these mechanisms by transcranial direct current stimulation (tDCS) and to probe behavioral outcomes reflecting the perception of ABAB streaming sequences. We hypothesized that tDCS by modulating cortical excitability causes a change in the separateness of the representations of A and B tones, which leads to a change in the proportions of one-stream and two-stream percepts. To test this, 22 subjects were presented with ambiguous ABAB sequences of three different frequency separations (∆F) and had to decide on their current percept after receiving sham, anodal, or cathodal tDCS over the left auditory cortex. We could confirm our hypothesis at the most ambiguous ∆F condition of 6 semitones. For anodal compared with sham and cathodal stimulation, we found a significant decrease in the proportion of two-stream perception and an increase in the proportion of one-stream perception. The results demonstrate the feasibility of using tDCS to probe mechanisms underlying auditory streaming through the use of various behavioral measures. Moreover, this approach allows one to probe the functions of auditory regions and their interactions with other processing stages. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

A power-efficient switchable CML driver at 10 Gbps

International Nuclear Information System (INIS)

Chen Peipei; Li Lei; Liu Huihua

2016-01-01

High static power limits the application of conventional current-mode logic(CML). This paper presents a power-efficient switchable CML driver, which achieves a significant current saving by 75% compared with conventional ones. Implemented in the 130 nm CMOS technology process, the proposed CML driver just occupies an area about 0.003 mm 2 and provides a robust differential signal of 1600 mV for 10 Gbps optical line terminal (OLT) with a total current of 10 mA. The peak-to-peak jitter is about 4 ps (0.04T UI ) and the offset voltage is 347.2 mV @ 1600 mV PP . (paper)

Short and long term effects of left and bilateral repetitive transcranial magnetic stimulation in schizophrenia patients with auditory verbal hallucinations: a randomized controlled trial.

Directory of Open Access Journals (Sweden)

Leonie Bais

Full Text Available BACKGROUND: Repetitive transcranial magnetic stimulation of the left temporo-parietal junction area has been studied as a treatment option for auditory verbal hallucinations. Although the right temporo-parietal junction area has also shown involvement in the genesis of auditory verbal hallucinations, no studies have used bilateral stimulation. Moreover, little is known about durability effects. We studied the short and long term effects of 1 Hz treatment of the left temporo-parietal junction area in schizophrenia patients with persistent auditory verbal hallucinations, compared to sham stimulation, and added an extra treatment arm of bilateral TPJ area stimulation. METHODS: In this randomized controlled trial, 51 patients diagnosed with schizophrenia and persistent auditory verbal hallucinations were randomly allocated to treatment of the left or bilateral temporo-parietal junction area or sham treatment. Patients were treated for six days, twice daily for 20 minutes. Short term efficacy was measured with the Positive and Negative Syndrome Scale (PANSS, the Auditory Hallucinations Rating Scale (AHRS, and the Positive and Negative Affect Scale (PANAS. We included follow-up measures with the AHRS and PANAS at four weeks and three months. RESULTS: The interaction between time and treatment for Hallucination item P3 of the PANSS showed a trend for significance, caused by a small reduction of scores in the left group. Although self-reported hallucination scores, as measured with the AHRS and PANAS, decreased significantly during the trial period, there were no differences between the three treatment groups. CONCLUSION: We did not find convincing evidence for the efficacy of left-sided rTMS, compared to sham rTMS. Moreover, bilateral rTMS was not superior over left rTMS or sham in improving AVH. Optimizing treatment parameters may result in stronger evidence for the efficacy of rTMS treatment of AVH. Moreover, future research should consider

Conductive Boron-Doped Graphene as an Ideal Material for Electrocatalytically Switchable and High-Capacity Hydrogen Storage.

Science.gov (United States)

Tan, Xin; Tahini, Hassan A; Smith, Sean C

2016-12-07

Electrocatalytic, switchable hydrogen storage promises both tunable kinetics and facile reversibility without the need for specific catalysts. The feasibility of this approach relies on having materials that are easy to synthesize, possessing good electrical conductivities. Graphitic carbon nitride (g-C 4 N 3 ) has been predicted to display charge-responsive binding with molecular hydrogen-the only such conductive sorbent material that has been discovered to date. As yet, however, this conductive variant of graphitic carbon nitride is not readily synthesized by scalable methods. Here, we examine the possibility of conductive and easily synthesized boron-doped graphene nanosheets (B-doped graphene) as sorbent materials for practical applications of electrocatalytically switchable hydrogen storage. Using first-principle calculations, we find that the adsorption energy of H 2 molecules on B-doped graphene can be dramatically enhanced by removing electrons from and thereby positively charging the adsorbent. Thus, by controlling charge injected or depleted from the adsorbent, one can effectively tune the storage/release processes which occur spontaneously without any energy barriers. At full hydrogen coverage, the positively charged BC 5 achieves high storage capacities up to 5.3 wt %. Importantly, B-doped graphene, such as BC 49 , BC 7 , and BC 5 , have good electrical conductivity and can be easily synthesized by scalable methods, which positions this class of material as a very good candidate for charge injection/release. These predictions pave the route for practical implementation of electrocatalytic systems with switchable storage/release capacities that offer high capacity for hydrogen storage.

Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation.

Science.gov (United States)

Vosskuhl, Johannes; Huster, René J; Herrmann, Christoph S

2015-01-01

Working memory (WM) and short-term memory (STM) supposedly rely on the phase-amplitude coupling (PAC) of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual's memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS). To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N = 33) were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG) was measured before stimulation and analyzed with regard to the properties of PAC between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity.

Switchable and Tunable Aerodynamic Drag on Cylinders

Science.gov (United States)

Guttag, Mark; Lopéz Jiménez, Francisco; Upadhyaya, Priyank; Kumar, Shanmugam; Reis, Pedro

We report results on the performance of Smart Morphable Surfaces (Smporhs) that can be mounted onto cylindrical structures to actively reduce their aerodynamic drag. Our system comprises of an elastomeric thin shell with a series of carefully designed subsurface cavities that, once depressurized, lead to a dramatic deformation of the surface topography, on demand. Our design is inspired by the morphology of the giant cactus (Carnegiea gigantea) which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. We perform systematic wind tunnel tests on cylinders covered with our Smorphs and characterize their aerodynamic performance. The switchable and tunable nature of our system offers substantial advantages for aerodynamic performance when compared to static topographies, due to their operation over a wider range of flow conditions.

Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation

OpenAIRE

Kwon, Yong Hyun; Jang, Sung Ho

2012-01-01

We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel coun...

Seizure Induced by Deep Transcranial Magnetic Stimulation in an Adolescent with Depression.

Science.gov (United States)

Cullen, Kathryn R; Jasberg, Suzanne; Nelson, Brent; Klimes-Dougan, Bonnie; Lim, Kelvin O; Croarkin, Paul E

2016-09-01

Deep transcranial magnetic stimulation (TMS) with an H-1 coil was recently approved by the U.S. Food and Drug Administration (U.S. FDA) for treatment-resistant depression (TRD) in adults. Studies assessing the safety and effectiveness of deep TMS in adolescent TRD are lacking. The purpose of this brief report is to provide a case history of an adolescent enrolled in an investigational deep TMS protocol. A case history is described of the first participant of a sham-controlled clinical trial who had a seizure in the course of deep TMS with parameter settings extrapolated from the adult studies that led to US FDA approval (H-1 coil, 120% target stimulation intensity, 18 Hz, 55 trains of 2-second duration, total 1980 pulses). The participant was a 17-year-old unmedicated female, with no significant medical history and no history of seizures or of drug or alcohol use. Brain magnetic resonance imaging showed no structural abnormalities. She initially received sham, which was well tolerated. During active treatment sessions, titration began at 85% of motor threshold (MT) and increased by 5% per day. Her weekly MT measurements were stable. On her first day of 120% MT (8th active treatment), during the 48th train, the participant had a generalized, tonic-clonic seizure that lasted 90 seconds and resolved spontaneously. She had an emergency medicine evaluation and was discharged home without anticonvulsant medications. There were no further seizures reported at a 6-month follow-up. We report a deep TMS-induced generalized tonic-clonic seizure in an adolescent with TRD participating in a clinical trial. Given the demonstrated benefits of deep TMS for adult TRD, research investigating its use in adolescents with TRD is an important area. However, in light of this experience, additional precautions for adolescents should be considered. We propose that further dose-finding investigations are needed to refine adolescent-specific parameters that may be safe and effective for

Properties of Augmented Kohn-Sham Potential for Energy as Simple Sum of Orbital Energies.

Science.gov (United States)

Zahariev, Federico; Levy, Mel

2017-01-12

A recent modification to the traditional Kohn-Sham method ( Levy , M. ; Zahariev , F. Phys. Rev. Lett. 2014 , 113 , 113002 ; Levy , M. ; Zahariev , F. Mol. Phys. 2016 , 114 , 1162 - 1164 ), which gives the ground-state energy as a direct sum of the occupied orbital energies, is discussed and its properties are numerically illustrated on representative atoms and ions. It is observed that current approximate density functionals tend to give surprisingly small errors for the highest occupied orbital energies that are obtained with the augmented potential. The appropriately shifted Kohn-Sham potential is the basic object within this direct-energy Kohn-Sham method and needs to be approximated. To facilitate approximations, several constraints to the augmented Kohn-Sham potential are presented.

Configurational forces in electronic structure calculations using Kohn-Sham density functional theory

Science.gov (United States)

Motamarri, Phani; Gavini, Vikram

2018-04-01

We derive the expressions for configurational forces in Kohn-Sham density functional theory, which correspond to the generalized variational force computed as the derivative of the Kohn-Sham energy functional with respect to the position of a material point x . These configurational forces that result from the inner variations of the Kohn-Sham energy functional provide a unified framework to compute atomic forces as well as stress tensor for geometry optimization. Importantly, owing to the variational nature of the formulation, these configurational forces inherently account for the Pulay corrections. The formulation presented in this work treats both pseudopotential and all-electron calculations in a single framework, and employs a local variational real-space formulation of Kohn-Sham density functional theory (DFT) expressed in terms of the nonorthogonal wave functions that is amenable to reduced-order scaling techniques. We demonstrate the accuracy and performance of the proposed configurational force approach on benchmark all-electron and pseudopotential calculations conducted using higher-order finite-element discretization. To this end, we examine the rates of convergence of the finite-element discretization in the computed forces and stresses for various materials systems, and, further, verify the accuracy from finite differencing the energy. Wherever applicable, we also compare the forces and stresses with those obtained from Kohn-Sham DFT calculations employing plane-wave basis (pseudopotential calculations) and Gaussian basis (all-electron calculations). Finally, we verify the accuracy of the forces on large materials systems involving a metallic aluminum nanocluster containing 666 atoms and an alkane chain containing 902 atoms, where the Kohn-Sham electronic ground state is computed using a reduced-order scaling subspace projection technique [P. Motamarri and V. Gavini, Phys. Rev. B 90, 115127 (2014), 10.1103/PhysRevB.90.115127].

Effects of Anodal Transcranial Direct Current Stimulation on Visually Guided Learning of Grip Force Control

Directory of Open Access Journals (Sweden)

Tamas Minarik

2015-03-01

Full Text Available Anodal transcranial Direct Current Stimulation (tDCS has been shown to be an effective non-invasive brain stimulation method for improving cognitive and motor functioning in patients with neurological deficits. tDCS over motor cortex (M1, for instance, facilitates motor learning in stroke patients. However, the literature on anodal tDCS effects on motor learning in healthy participants is inconclusive, and the effects of tDCS on visuo-motor integration are not well understood. In the present study we examined whether tDCS over the contralateral motor cortex enhances learning of grip-force output in a visually guided feedback task in young and neurologically healthy volunteers. Twenty minutes of 1 mA anodal tDCS were applied over the primary motor cortex (M1 contralateral to the dominant (right hand, during the first half of a 40 min power-grip task. This task required the control of a visual signal by modulating the strength of the power-grip for six seconds per trial. Each participant completed a two-session sham-controlled crossover protocol. The stimulation conditions were counterbalanced across participants and the sessions were one week apart. Performance measures comprised time-on-target and target-deviation, and were calculated for the periods of stimulation (or sham and during the afterphase respectively. Statistical analyses revealed significant performance improvements over the stimulation and the afterphase, but this learning effect was not modulated by tDCS condition. This suggests that the form of visuomotor learning taking place in the present task was not sensitive to neurostimulation. These null effects, together with similar reports for other types of motor tasks, lead to the proposition that tDCS facilitation of motor learning might be restricted to cases or situations where the motor system is challenged, such as motor deficits, advanced age, or very high task demand.

Motor/Prefrontal Transcranial Direct Current Stimulation (tDCS) Following Lumbar Surgery Reduces Postoperative Analgesia Use.

Science.gov (United States)

Glaser, John; Reeves, Scott T; Stoll, William David; Epperson, Thomas I; Hilbert, Megan; Madan, Alok; George, Mark S; Borckardt, Jeffrey J

2016-05-01

Randomized, controlled pilot trial. The present study is the first randomized, double-blind, sham-controlled pilot clinical trial of transcranial direct current stimulation (tDCS) for pain and patient-controlled analgesia (PCA) opioid usage among patients receiving spine surgery. Lumbar spinal surgeries are common, and while pain is often a complaint that precedes surgical intervention, the procedures themselves are associated with considerable postoperative pain lasting days to weeks. Adequate postoperative pain control is an important factor in determining recovery and new analgesic strategies are needed that can be used adjunctively to existing strategies potentially to reduce reliance on opioid analgesia. Several novel brain stimulation technologies including tDCS are beginning to demonstrate promise as treatments for a variety of pain conditions. Twenty-seven patients undergoing lumbar spine procedures at Medical University of South Carolina were randomly assigned to receive four 20-minute sessions of real or sham tDCS during their postsurgical hospital stay. Patient-administered hydromorphone usage was tracked along with numeric rating scale pain ratings. The effect of tDCS on the slope of the cumulative PCA curve was significant (P tDCS was associated with a 23% reduction in PCA usage. In the real tDCS group a 31% reduction was observed in pain-at-its-least ratings from admission to discharge (P = 0.027), but no other changes in numeric rating scale pain ratings were significant in either group. The present pilot trial is the first study to demonstrate an opioid sparing effect of tDCS after spine surgical procedures. Although this was a small pilot trial in a heterogeneous sample of spinal surgery patients, a moderate effect-size was observed for tDCS, suggesting that future work in this area is warranted. 2.

Effects of transcranial direct current stimulation on the control of finger force during dexterous manipulation in healthy older adults.

Directory of Open Access Journals (Sweden)

Pranav J Parikh

Full Text Available The contribution of poor finger force control to age-related decline in manual dexterity is above and beyond ubiquitous behavioral slowing. Altered control of the finger forces can impart unwanted torque on the object affecting its orientation, thus impairing manual performance. Anodal transcranial direct current stimulation (tDCS over primary motor cortex (M1 has been shown to improve the performance speed on manual tasks in older adults. However, the effects of anodal tDCS over M1 on the finger force control during object manipulation in older adults remain to be fully explored. Here we determined the effects of anodal tDCS over M1 on the control of grip force in older adults while they manipulated an object with an uncertain mechanical property. Eight healthy older adults were instructed to grip and lift an object whose contact surfaces were unexpectedly made more or less slippery across trials using acetate and sandpaper surfaces, respectively. Subjects performed this task before and after receiving anodal or sham tDCS over M1 on two separate sessions using a cross-over design. We found that older adults used significantly lower grip force following anodal tDCS compared to sham tDCS. Friction measured at the finger-object interface remained invariant after anodal and sham tDCS. These findings suggest that anodal tDCS over M1 improved the control of grip force during object manipulation in healthy older adults. Although the cortical networks for representing objects and manipulative actions are complex, the reduction in grip force following anodal tDCS over M1 might be due to a cortical excitation yielding improved processing of object-specific sensory information and its integration with the motor commands for production of manipulative forces. Our findings indicate that tDCS has a potential to improve the control of finger force during dexterous manipulation in older adults.

Grafted membranes and substrates having surfaces with switchable superoleophilicity and superoleophobicity and applications thereof

KAUST Repository

Zhang, Lianbin

2013-10-10

Disclosed herein are surface-modified membranes and other surface-modified substrates exhibiting switchable oleophobicity and oleophilicity in aqueous media. These membranes and substrates may be used for variety of applications, including controllable oil/water separation processes, oil spill cleanup, and oil/water purification. Also provided are the making and processing of such surface-modified membranes and other surface-modified substrates.

Grafted membranes and substrates having surfaces with switchable superoleophilicity and superoleophobicity and applications thereof

KAUST Repository

Zhang, Lianbin; Wang, Peng

2013-01-01

Disclosed herein are surface-modified membranes and other surface-modified substrates exhibiting switchable oleophobicity and oleophilicity in aqueous media. These membranes and substrates may be used for variety of applications, including controllable oil/water separation processes, oil spill cleanup, and oil/water purification. Also provided are the making and processing of such surface-modified membranes and other surface-modified substrates.

The positive effects of high-frequency right dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation on memory, correlated with increases in brain metabolites detected by proton magnetic resonance spectroscopy in recently detoxified alcohol-dependent patients

Directory of Open Access Journals (Sweden)

Qiao J

2016-09-01

Full Text Available Jun Qiao,1,2 Guixing Jin,1,2 Licun Lei,3 Lan Wang,1,2 Yaqiang Du,3 Xueyi Wang1,2 1Institute of Mental Health, The First Hospital of Hebei Medical University, 2Brain Ageing and Cognitive Neuroscience Laboratory, Hebei Medical University, 3Department of Radiology, The First Hospital of Hebei Medical University, Hebei, People’s Republic of China Objective: To explore the effect of right dorsolateral prefrontal cortex (DLPFC repetitive transcranial magnetic stimulation (rTMS on memory, and its correlation with levels of hippocampal brain metabolites detected by proton magnetic resonance spectroscopy (1H-MRS in recently detoxified alcohol-dependent patients. Materials and methods: In this randomized, double-blind sham-controlled trial, alcohol-dependent patients were enrolled and randomized into two groups: the experimental group (rTMS, 10 Hz, on right DLPFC, 20 sessions and the control group (sham stimulation. Memory function was assessed using Hopkins Verbal Learning Test-Revised (HVLT-R and Brief Visuospatial Memory Test-Revised (BVMT-R before and after treatment. 1H-MRS was used to detect the levels of N-acetyl aspartic acid (NAA, choline (Cho, and creatine (Cr in bilateral hippocampi before and after treatment. Results: Thirty-eight patients (18 in the experimental group and 20 in the control group were included in the analyses. The experimental group showed significantly greater changes in HVLT-R, BVMT-R, NAA/Cr, and Cho/Cr after rTMS from baseline than the control group. The percentage change in BVMT-R and HVLT-R correlated with the percentage change in NAA/Cr and Cho/Cr in the right brain. Conclusion: High-frequency right DLPFC rTMS was associated with improvement in memory dysfunction, which is correlated with levels of hippocampal brain metabolites detected by 1H-MRS in recently detoxified alcohol-dependent patients. Keywords: alcohol dependence, memory, repetitive transcranial magnetic stimulation, MR spectroscopy

Ten minutes of 1 mA transcranial direct current stimulation was well tolerated by children and adolescents: Self-reports and resting state EEG analysis.

Science.gov (United States)

Moliadze, Vera; Andreas, Saskia; Lyzhko, Ekaterina; Schmanke, Till; Gurashvili, Tea; Freitag, Christine M; Siniatchkin, Michael

2015-10-01

Transcranial direct current stimulation (tDCS) is a promising and well-tolerated method of non-invasive brain stimulation, by which cortical excitability can be modulated. However, the effects of tDCS on the developing brain are still unknown, and knowledge about its tolerability in children and adolescents is still lacking. Safety and tolerability of tDCS was assessed in children and adolescents by self-reports and spectral characteristics of electroencephalogram (EEG) recordings. Nineteen typically developing children and adolescents aged 11-16 years participated in the study. Anodal and cathodal tDCS as well as sham stimulation were applied for a duration of 10 min over the left primary motor cortex (M1), each with an intensity of 1 mA. Subjects were unable to identify whether they had received active or sham stimulation, and all participants tolerated the stimulation well with a low rate of adverse events in both groups and no serious adverse events. No pathological oscillations, in particular, no markers of epileptiform activity after 1mA tDCS were detected in any of the EEG analyses. In summary, our study demonstrates that tDCS with 1mA intensity over 10 min is well tolerated, and thus may be used as an experimental and treatment method in the pediatric population. Copyright © 2015 Elsevier Inc. All rights reserved.

Transcranial brain stimulation: closing the loop between brain and stimulation

DEFF Research Database (Denmark)

Karabanov, Anke; Thielscher, Axel; Siebner, Hartwig Roman

2016-01-01

-related and state-related variability. Fluctuations in brain-states can be traced online with functional brain imaging and inform the timing or other settings of transcranial brain stimulation. State-informed open-loop stimulation is aligned to the expression of a predefined brain state, according to prespecified......PURPOSE OF REVIEW: To discuss recent strategies for boosting the efficacy of noninvasive transcranial brain stimulation to improve human brain function. RECENT FINDINGS: Recent research exposed substantial intra- and inter-individual variability in response to plasticity-inducing transcranial brain...... stimulation. Trait-related and state-related determinants contribute to this variability, challenging the standard approach to apply stimulation in a rigid, one-size-fits-all fashion. Several strategies have been identified to reduce variability and maximize the plasticity-inducing effects of noninvasive...

Illusory sensation of movement induced by repetitive transcranial magnetic stimulation

DEFF Research Database (Denmark)

Christensen, Mark Schram; Lundbye-Jensen, Jesper; Grey, Michael James

2010-01-01

Human movement sense relies on both somatosensory feedback and on knowledge of the motor commands used to produce the movement. We have induced a movement illusion using repetitive transcranial magnetic stimulation over primary motor cortex and dorsal premotor cortex in the absence of limb movement...... and its associated somatosensory feedback. Afferent and efferent neural signalling was abolished in the arm with ischemic nerve block, and in the leg with spinal nerve block. Movement sensation was assessed following trains of high-frequency repetitive transcranial magnetic stimulation applied over...... premotor cortex stimulation was less affected by sensory and motor deprivation than was primary motor cortex stimulation. We propose that repetitive transcranial magnetic stimulation over dorsal premotor cortex produces a corollary discharge that is perceived as movement....

Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: Toward controllable oil/water separation

KAUST Repository

Zhang, L.

2012-02-01

Advanced materials with surfaces that have controllable oil wettability when submerged in aqueous media have great potential for various underwater applications. Here we have developed smart surfaces on commonly used materials, including non-woven textiles and polyurethane sponges, which are able to switch between superoleophilicity and superoleophobicity in aqueous media. The smart surfaces are obtained by grafting a block copolymer, comprising blocks of pH-responsive poly(2-vinylpyridine) and oleophilic/hydrophobic polydimethylsiloxane (i.e., P2VP-b-PDMS) on these materials. The P2VP block can alter its wettability and its conformation via protonation and deprotonation in response to the pH of the aqueous media, which provides controllable and switchable access of oil by the PDMS block, resulting in the switchable surface oil wettability in the aqueous media. On the other hand, the high flexibility of the PDMS block facilitates the reversible switching of the surface oil wettability. As a proof of concept, we also demonstrate that materials functionalized with our smart surfaces can be used for highly controllable oil/water separation processes.

Safety and feasibility of transcranial direct current stimulation in amyotrophic lateral sclerosis - a pilot study with a single subject experimental design.

Science.gov (United States)

Madhavan, Sangeetha; Sivaramakrishnan, Anjali; Bond, Sam; Jiang, Qin Li

2018-02-28

Transcranial direct current stimulation (tDCS) has been explored as a neuromodulatory tool to prime motor function in several neurological disorders. Studies using tDCS in amyotrophic lateral sclerosis (ALS) are limited. We investigated the safety, feasibility and effects of long-term tDCS in an individual with ALS. A 36-year-old male diagnosed with clinically definite ALS received 12 sessions each of anodal, sham, and cathodal tDCS. Outcome measures included disease progression (revised ALS functional rating scale (ALSFRS-R)), clinical measures of endurance and mobility, and corticomotor excitability. No adverse events or change in disease progression were noticed during the study. Small improvement in gait speed (15% increase) was noticed with anodal tDCS only. This case study demonstrates the safety and feasibility of long-term facilitatory and inhibitory tDCS on a single participant with ALS. This study serves as a guideline for implementing tDCS in future ALS trials.

Noninvasive transcranial brain stimulation and pain.

Science.gov (United States)

Rosen, Allyson C; Ramkumar, Mukund; Nguyen, Tam; Hoeft, Fumiko

2009-02-01

Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are two noninvasive brain stimulation techniques that can modulate activity in specific regions of the cortex. At this point, their use in brain stimulation is primarily investigational; however, there is clear evidence that these tools can reduce pain and modify neurophysiologic correlates of the pain experience. TMS has also been used to predict response to surgically implanted stimulation for the treatment of chronic pain. Furthermore, TMS and tDCS can be applied with other techniques, such as event-related potentials and pharmacologic manipulation, to illuminate the underlying physiologic mechanisms of normal and pathological pain. This review presents a description and overview of the uses of two major brain stimulation techniques and a listing of useful references for further study.

THE ETHICS OF SHAM SURGERY IN PARKINSON'S DISEASE: BACK TO THE FUTURE?

Science.gov (United States)

Swift, Teresa; Huxtable, Richard

2013-01-01

Despite intense academic debate in the recent past over the use of ‘sham surgery’ control groups in research, there has been a recent resurgence in their use in the field of neurodegenerative disease. Yet the primacy of ethical arguments in favour of sham surgery controls is not yet established. Preliminary empirical research shows an asymmetry between the views of neurosurgical researchers and patients on the subject, while different ethical guidelines and regulations support conflicting interpretations. Research ethics committees faced with a proposal involving sham surgery should be aware of its ethical complexities. An overview of recent and current placebo-controlled surgical trials in the field of Parkinson's Disease is provided here, followed by an analysis of the key ethical issues which such trials raise. PMID:22150772

Approximating the Shifted Hartree-Exchange-Correlation Potential in Direct Energy Kohn-Sham Theory.

Science.gov (United States)

Sharpe, Daniel J; Levy, Mel; Tozer, David J

2018-02-13

Levy and Zahariev [Phys. Rev. Lett. 113 113002 (2014)] have proposed a new approach for performing density functional theory calculations, termed direct energy Kohn-Sham (DEKS) theory. In this approach, the electronic energy equals the sum of orbital energies, obtained from Kohn-Sham-like orbital equations involving a shifted Hartree-exchange-correlation potential, which must be approximated. In the present study, density scaling homogeneity considerations are used to facilitate DEKS calculations on a series of atoms and molecules, leading to three nonlocal approximations to the shifted potential. The first two rely on preliminary Kohn-Sham calculations using a standard generalized gradient approximation (GGA) exchange-correlation functional and the results illustrate the benefit of describing the dominant Hartree component of the shift exactly. A uniform electron gas analysis is used to eliminate the need for these preliminary Kohn-Sham calculations, leading to a potential with an unconventional form that yields encouraging results, providing strong motivation for further research in DEKS theory.

Temperature-dependent transformation thermotics for unsteady states: Switchable concentrator for transient heat flow

Energy Technology Data Exchange (ETDEWEB)

Li, Ying, E-mail: 13110290008@fudan.edu.cn [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China); Shen, Xiangying, E-mail: 13110190068@fudan.edu.cn [Department of Physics, State Key Laboratory of Surface Physics, and Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433 (China); Huang, Jiping, E-mail: jphuang@fudan.edu.cn [Department of Physics, State Key Laboratory of Surface Physics, and Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433 (China); Ni, Yushan, E-mail: niyushan@fudan.edu.cn [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China)

2016-04-22

For manipulating heat flow efficiently, recently we established a theory of temperature-dependent transformation thermotics which holds for steady-state cases. Here, we develop the theory to unsteady-state cases by considering the generalized Fourier's law for transient thermal conduction. As a result, we are allowed to propose a new class of intelligent thermal metamaterial — switchable concentrator, which is made of inhomogeneous anisotropic materials. When environmental temperature is below or above a critical value, the concentrator is automatically switched on, namely, it helps to focus heat flux in a specific region. However, the focusing does not affect the distribution pattern of temperature outside the concentrator. We also perform finite-element simulations to confirm the switching effect according to the effective medium theory by assembling homogeneous isotropic materials, which bring more convenience for experimental fabrication than inhomogeneous anisotropic materials. This work may help to figure out new intelligent thermal devices, which provide more flexibility in controlling heat flow, and it may also be useful in other fields that are sensitive to temperature gradient, such as the Seebeck effect. - Highlights: • Established the unsteady-state temperature dependent transformation thermotics. • A thermal concentrator with switchable functionality. • An effective-medium design for experimental realization.

Digitally switchable multi-focal lens using freeform optics.

Science.gov (United States)

Wang, Xuan; Qin, Yi; Hua, Hong; Lee, Yun-Han; Wu, Shin-Tson

2018-04-16

Optical technologies offering electrically tunable optical power have found a broad range of applications, from head-mounted displays for virtual and augmented reality applications to microscopy. In this paper, we present a novel design and prototype of a digitally switchable multi-focal lens (MFL) that offers the capability of rapidly switching the optical power of the system among multiple foci. It consists of a freeform singlet and a customized programmable optical shutter array (POSA). Time-multiplexed multiple foci can be obtained by electrically controlling the POSA to switch the light path through different segments of the freeform singlet rapidly. While this method can be applied to a broad range of imaging and display systems, we experimentally demonstrate a proof-of-concept prototype for a multi-foci imaging system.

Promoting Sleep Oscillations and Their Functional Coupling by Transcranial Stimulation Enhances Memory Consolidation in Mild Cognitive Impairment.

Science.gov (United States)

Ladenbauer, Julia; Ladenbauer, Josef; Külzow, Nadine; de Boor, Rebecca; Avramova, Elena; Grittner, Ulrike; Flöel, Agnes

2017-07-26

Alzheimer's disease (AD) not only involves loss of memory functions, but also prominent deterioration of sleep physiology, which is already evident at the stage of mild cognitive impairment (MCI). Cortical slow oscillations (SO; 0.5-1 Hz) and thalamocortical spindle activity (12-15 Hz) during sleep, and their temporal coordination, are considered critical for memory formation. We investigated the potential of slow oscillatory transcranial direct current stimulation (so-tDCS), applied during a daytime nap in a sleep-state-dependent manner, to modulate these activity patterns and sleep-related memory consolidation in nine male and seven female human patients with MCI. Stimulation significantly increased overall SO and spindle power, amplified spindle power during SO up-phases, and led to stronger synchronization between SO and spindle power fluctuations in EEG recordings. Moreover, visual declarative memory was improved by so-tDCS compared with sham stimulation and was associated with stronger synchronization. These findings indicate a well-tolerated therapeutic approach for disordered sleep physiology and memory deficits in MCI patients and advance our understanding of offline memory consolidation. SIGNIFICANCE STATEMENT In the light of increasing evidence that sleep disruption is crucially involved in the progression of Alzheimer's disease (AD), sleep appears as a promising treatment target in this pathology, particularly to counteract memory decline. This study demonstrates the potential of a noninvasive brain stimulation method during sleep in patients with mild cognitive impairment (MCI), a precursor of AD, and advances our understanding of its mechanism. We provide first time evidence that slow oscillatory transcranial stimulation amplifies the functional cross-frequency coupling between memory-relevant brain oscillations and improves visual memory consolidation in patients with MCI. Copyright © 2017 the authors 0270-6474/17/377111-14$15.00/0.

Electrically switchable holographic liquid crystal/polymer Fresnel lens using a Michelson interferometer.

Science.gov (United States)

Jashnsaz, Hossein; Mohajerani, Ezeddin; Nemati, Hossein; Razavi, Seyed Hossein; Alidokht, Isa Ahmad

2011-06-10

A holographic technique for fabricating an electrically switchable liquid crystal/polymer composite Fresnel lens is reported. A Michelson interferometer is used to produce the required Fresnel pattern, by placing a convex lens into one path of the interferometer. Simplicity of the method and the possibility of fabricating different focal length lenses in a single arrangement are advantages of the method. The performance of the fabricated lens was demonstrated and its electro-optical properties were investigated for its primary focal length.

Transcranial magnetic stimulation potentiates glutamatergic neurotransmission in depressed adolescents.

Science.gov (United States)

Croarkin, Paul E; Nakonezny, Paul A; Wall, Christopher A; Murphy, Lauren L; Sampson, Shirlene M; Frye, Mark A; Port, John D

2016-01-30

Abnormalities in glutamate neurotransmission may have a role in the pathophysiology of adolescent depression. The present pilot study examined changes in cortical glutamine/glutamate ratios in depressed adolescents receiving high-frequency repetitive transcranial magnetic stimulation. Ten adolescents with treatment-refractory major depressive disorder received up to 30 sessions of 10-Hz repetitive transcranial magnetic stimulation at 120% motor threshold with 3000 pulses per session applied to the left dorsolateral prefrontal cortex. Baseline, posttreatment, and 6-month follow-up proton magnetic resonance spectroscopy scans of the anterior cingulate cortex and left dorsolateral prefrontal cortex were collected at 3T with 8-cm(3) voxels. Glutamate metabolites were quantified with 2 distinct proton magnetic resonance spectroscopy sequences in each brain region. After repetitive transcranial magnetic stimulation and at 6 months of follow-up, glutamine/glutamate ratios increased in the anterior cingulate cortex and left dorsolateral prefrontal cortex with both measurements. The increase in the glutamine/glutamate ratio reached statistical significance with the TE-optimized PRESS sequence in the anterior cingulate cortex. Glutamine/glutamate ratios increased in conjunction with depressive symptom improvement. This reached statistical significance with the TE-optimized PRESS sequence in the left dorsolateral prefrontal cortex. High-frequency repetitive transcranial magnetic stimulation applied to the left dorsolateral prefrontal cortex may modulate glutamate neurochemistry in depressed adolescents. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effects of transcranial direct current stimulation over the supplementary motor area body weight-supported treadmill gait training in hemiparetic patients after stroke.

Science.gov (United States)

Manji, Atsushi; Amimoto, Kazu; Matsuda, Tadamitsu; Wada, Yoshiaki; Inaba, Akira; Ko, Sangkyun

2018-01-01

Transcranial direct current stimulation (tDCS) is used in a variety of disorders after stroke including upper limb motor dysfunctions, hemispatial neglect, aphasia, and apraxia, and its effectiveness has been demonstrated. Although gait ability is important for daily living, there were few reports of the use of tDCS to improve balance and gait ability. The supplementary motor area (SMA) was reported to play a potentially important role in balance recovery after stroke. We aimed to investigate the effect of combined therapy body weight-supported treadmill training (BWSTT) and tDCS on gait function recovery of stroke patients. Thirty stroke inpatients participated in this study. The two BWSTT periods of 1weeks each, with real tDCS (anode: front of Cz, cathode: inion, 1mA, 20min) on SMA and sham stimulation, were randomized in a double-blind crossover design. We measured the time required for the 10m Walk Test (10MWT) and Timed Up and Go (TUG) test before and after each period. We found that the real tDCS with BWSTT significantly improved gait speed (10MWT) and applicative walking ability (TUG), compared with BWSTT+sham stimulation periods (ptraining after stroke. The facilitative effects of tDCS on SMA possibly improved postural control during BWSTT. The results indicated the implications for the use of tDCS in balance and gait training rehabilitation after stroke. Copyright © 2017 Elsevier B.V. All rights reserved.

Switchable coupling for superconducting qubits using double resonance in the presence of crosstalk

International Nuclear Information System (INIS)

Ashhab, S.; Nori, Franco

2007-01-01

Several methods have been proposed recently to achieve switchable coupling between superconducting qubits. We discuss some of the main considerations regarding the feasibility of implementing one of those proposals: The double-resonance method. We analyze mainly issues related to the achievable effective coupling strength and the effects of crosstalk on this coupling mechanism. We also find a crosstalk-assisted coupling channel that can be an attractive alternative when implementing the double-resonance coupling proposal

A pilot study of cognitive training with and without transcranial direct current stimulation to improve cognition in older persons with HIV-related cognitive impairment

Directory of Open Access Journals (Sweden)

Ownby RL

2016-10-01

Full Text Available Raymond L Ownby,1 Amarilis Acevedo2 1Department of Psychiatry and Behavioral Medicine, 2College of Psychology, Nova Southeastern University, Fort Lauderdale, FL, USA Background: In spite of treatment advances, HIV infection is associated with cognitive deficits. This is even more important as many persons with HIV infection age and experience age-related cognitive impairments. Both computer-based cognitive training and transcranial direct current stimulation (tDCS have shown promise as interventions to improve cognitive function. In this study, we investigate the acceptability and efficacy of cognitive training with and without tDCS in older persons with HIV. Patients and methods: In this single-blind randomized study, participants were 14 individuals of whom 11 completed study procedures (mean age =51.5 years; nine men and two women with HIV-related mild neurocognitive disorder. Participants completed a battery of neuropsychological and self-report measures and then six 20-minute cognitive training sessions while receiving either active or sham anodal tDCS over the left dorsolateral prefrontal cortex. After training, participants completed the same measures. Success of the blind and participant reactions were assessed during a final interview. Assessments were completed by an assessor blind to treatment assignment. Pre- and post-training changes were evaluated via analysis of covariance yielding estimates of effect size. Results: All participants believed that they had been assigned to active treatment; nine of the 11 believed that the intervention had improved their cognitive functioning. Both participants who felt the intervention was ineffective were assigned to the sham condition. None of the planned tested interactions of time with treatment was significant, but 12 of 13 favored tDCS (P=0.08. All participants indicated that they would participate in similar studies in the future. Conclusion: Results show that both cognitive training via

A Kohn-Sham system at zero temperature

DEFF Research Database (Denmark)

Cornean, Horia; Hoke, K.; Neidhardt, H.

2008-01-01

A one-dimensional Kohn-Sham system for spin particles is considered which effectively describes semiconductor nanostructures, and which is investigated at zero temperature. We prove the existence of solutions and derive a priori estimates. For this purpose we find estimates for eigenvalues...... by monotonicity arguments. Finally, we investigate the behavior of the system if the temperature approaches zero....

Strong Correlation in Kohn-Sham Density Functional Theory

NARCIS (Netherlands)

Malet, F.; Gori Giorgi, P.

2012-01-01

We use the exact strong-interaction limit of the Hohenberg-Kohn energy density functional to approximate the exchange-correlation energy of the restricted Kohn-Sham scheme. Our approximation corresponds to a highly nonlocal density functional whose functional derivative can be easily constructed,

Transcranial Doppler Ultrasound in Peninsular Arab Patients With Sickle Cell Disease.

Science.gov (United States)

Adekile, Adekunle; Hassan, Meaad; Asbeutah, Akram; Al-Hinai, Mohamed; Trad, Omar; Farhan, Nayef

2018-05-06

Transcranial Doppler ultrasound is used to identify patients with sickle cell disease (SCD) at risk for stroke. We performed transcranial Doppler studies in patients from 4 countries in the Arabian Peninsula (Kuwait, Oman, Iraq, and United Arab Emirates) to document the prevalence of abnormal transcranial Doppler findings. The patients were recruited from outpatient clinics and studied in a steady state. Transcranial Doppler examinations were performed with standard equipment by experienced operators. The time-averaged maximum mean velocity (TAMMV) was documented in the arteries of the circle of Willis. The hemoglobin (Hb) genotype was confirmed, and the fetal Hb level and complete blood counts were determined. There were 415 patients in the study, aged 2 to 18 years (mean ± SD, 8.6 ± 3.5 years). None of the patients had an abnormal TAMMV (ie, > 200 cm/s), whereas only 13 (3.1%), all from Iraq, had conditional values (170-200 cm/s) in the right middle cerebral artery and 7 (1.7%) in the left middle cerebral artery. There were no consistent TAMMV differences among male and female patients or in patients with different Hb genotypes (sickle cell anemia, sickle cell β 0- thalassemia, and sickle D). The use of hydroxyurea was associated with a lower TAMMV, whereas a blood transfusion history had no influence. Total hemoglobin, reticulocyte count, serum bilirubin, and fetal Hb values showed varying degrees of association with the TAMMV in the different vessels. This study has demonstrated the rarity of abnormal transcranial Doppler findings among Peninsular Arab patients with SCD. The guidelines for transcranial Doppler screening in this population need further studies and recommendations. © 2018 by the American Institute of Ultrasound in Medicine.

Effects of Combining a Brief Cognitive Intervention with Transcranial Direct Current Stimulation on Pain Tolerance: A Randomized Controlled Pilot Study.

Science.gov (United States)

Powers, Abigail; Madan, Alok; Hilbert, Megan; Reeves, Scott T; George, Mark; Nash, Michael R; Borckardt, Jeffrey J

2018-04-01

Cognitive behavioral therapy has been shown to be effective for treating chronic pain, and a growing literature shows the potential analgesic effects of minimally invasive brain stimulation. However, few studies have systematically investigated the potential benefits associated with combining approaches. The goal of this pilot laboratory study was to investigate the combination of a brief cognitive restructuring intervention and transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex in affecting pain tolerance. Randomized, double-blind, placebo-controlled laboratory pilot. Medical University of South Carolina. A total of 79 healthy adult volunteers. Subjects were randomized into one of six groups: 1) anodal tDCS plus a brief cognitive intervention (BCI); 2) anodal tDCS plus pain education; 3) cathodal tDCS plus BCI; 4) cathodal tDCS plus pain education; 5) sham tDCS plus BCI; and 6) sham tDCS plus pain education. Participants underwent thermal pain tolerance testing pre- and postintervention using the Method of Limits. A significant main effect for time (pre-post intervention) was found, as well as for baseline thermal pain tolerance (covariate) in the model. A significant time × group interaction effect was found on thermal pain tolerance. Each of the five groups that received at least one active intervention outperformed the group receiving sham tDCS and pain education only (i.e., control group), with the exception of the anodal tDCS + education-only group. Cathodal tDCS combined with the BCI produced the largest analgesic effect. Combining cathodal tDCS with BCI yielded the largest analgesic effect of all the conditions tested. Future research might find stronger interactive effects of combined tDCS and a cognitive intervention with larger doses of each intervention. Because this controlled laboratory pilot employed an acute pain analogue and the cognitive intervention did not authentically represent cognitive behavioral

Effects of Transcranial Direct Current Stimulation on Expression of Immediate Early Genes (IEG’s)

Science.gov (United States)

2015-12-01

TRANSCRANIAL DIRECT CURRENT STIMULATION OF EXPRESSION OF IMMEDIATE EARLY GENES (IEG’S) Jessica...AND SUBTITLE Effects of Transcranial Direct Current Stimulation on Expression of Immediate Early Genes (IEG’s) 5a. CONTRACT NUMBER In-House 5b...community in better understanding what is occurring biologically during tDCS. 15. SUBJECT TERMS Transcranial direct current stimulation

Kohn-Sham potentials for fullerenes and spherical molecules

International Nuclear Information System (INIS)

Pavlyukh, Y.; Berakdar, J.

2010-01-01

We present a procedure for the construction of accurate Kohn-Sham potentials of quasispherical molecules starting from the first-principles valence densities. The method is demonstrated for the case of icosahedral C 20 2+ and C 60 molecules. Provided the density is N representable the Hohenberg-Kohn theorem guarantees the uniqueness of the obtained potentials. The potential is iteratively built following the suggestion of R. van Leeuwen and E. J. Baerends [Phys. Rev. A 49, 2421 (1994)]. The high symmetry of the molecules allows a parametrization of the angular dependence of the densities and the potentials using a small number of symmetry-adapted spherical harmonics. The radial behavior of these quantities is represented on a grid and the density is reconstructed from the approximate potential by numerically solving the coupled-channel Kohn-Sham equations. Subsequently, the potential is updated and the procedure is continued until convergence is achieved.

5 Hz repetitive transcranial magnetic stimulation over the ipsilesional sensory cortex enhances motor learning after stroke

Directory of Open Access Journals (Sweden)

Sonia M Brodie

2014-03-01

Full Text Available Sensory feedback is critical for motor learning, and thus to neurorehabilitation after stroke. Whether enhancing sensory feedback by applying excitatory repetitive transcranial magnetic stimulation (rTMS over the ipsilesional primary sensory cortex (IL-S1 might enhance motor learning in chronic stroke has yet to be investigated. The present study investigated the effects of 5 Hz rTMS over IL-S1 paired with skilled motor practice on motor learning, hemiparetic cutaneous somatosensation, and motor function. Individuals with unilateral chronic stroke were pseudo-randomly divided into either Active or Sham 5 Hz rTMS groups (n=11/group. Following stimulation, both groups practiced a Serial Tracking Task (STT with the hemiparetic arm; this was repeated for 5 days. Performance on the STT was quantified by response time, peak velocity, and cumulative distance tracked at baseline, during the 5 days of practice, and at a no-rTMS retention test. Cutaneous somatosensation was measured using two-point discrimination. Standardized sensorimotor tests were performed to assess whether the effects might generalize to impact hemiparetic arm function. The active 5Hz rTMS + training group demonstrated significantly greater improvements in STT performance [response time (F1,286.04=13.016, p< 0.0005, peak velocity (F1,285.95=4.111, p=0.044, and cumulative distance (F1,285.92=4.076, p=0.044] and cutaneous somatosensation (F1,21.15=8.793, p=0.007 across all sessions compared to the sham rTMS + training group. Measures of upper extremity motor function were not significantly different for either group. Our preliminary results suggest that, when paired with motor practice, 5Hz rTMS over IL-S1 enhances motor learning related change in individuals with chronic stroke, potentially as a consequence of improved cutaneous somatosensation, however no improvement in general upper extremity function was observed.

The right planum temporale is involved in stimulus-driven, auditory attention--evidence from transcranial magnetic stimulation.

Directory of Open Access Journals (Sweden)

Marco Hirnstein

Full Text Available It is well known that the planum temporale (PT area in the posterior temporal lobe carries out spectro-temporal analysis of auditory stimuli, which is crucial for speech, for example. There are suggestions that the PT is also involved in auditory attention, specifically in the discrimination and selection of stimuli from the left and right ear. However, direct evidence is missing so far. To examine the role of the PT in auditory attention we asked fourteen participants to complete the Bergen Dichotic Listening Test. In this test two different consonant-vowel syllables (e.g., "ba" and "da" are presented simultaneously, one to each ear, and participants are asked to verbally report the syllable they heard best or most clearly. Thus attentional selection of a syllable is stimulus-driven. Each participant completed the test three times: after their left and right PT (located with anatomical brain scans had been stimulated with repetitive transcranial magnetic stimulation (rTMS, which transiently interferes with normal brain functioning in the stimulated sites, and after sham stimulation, where participants were led to believe they had been stimulated but no rTMS was applied (control. After sham stimulation the typical right ear advantage emerged, that is, participants reported relatively more right than left ear syllables, reflecting a left-hemispheric dominance for language. rTMS over the right but not left PT significantly reduced the right ear advantage. This was the result of participants reporting more left and fewer right ear syllables after right PT stimulation, suggesting there was a leftward shift in stimulus selection. Taken together, our findings point to a new function of the PT in addition to auditory perception: particularly the right PT is involved in stimulus selection and (stimulus-driven, auditory attention.

Augmentation of Fear Extinction by Transcranial Direct Current Stimulation (tDCS

Directory of Open Access Journals (Sweden)

Natalie Dittert

2018-04-01

Full Text Available Although posttraumatic stress disorder (PTSD; DSM-V 309.82 and anxiety disorders (DSM-V 300.xx are widely spread mental disorders, the effectiveness of their therapy is still unsatisfying. Non-invasive brain-stimulation techniques like transcranial direct current stimulation (tDCS might be an option to improve extinction learning, which is a main functional factor of exposure-based therapy for anxiety disorders. To examine this hypothesis, we used a fear conditioning paradigm with female faces as conditioned stimuli (CS and a 95-dB female scream as unconditioned stimulus (UCS. We aimed to perform a tDCS of the ventromedial prefrontal cortex (vmPFC, which is mainly involved in the control of extinction-processes. Therefore, we applied two 4 × 4 cm electrodes approximately at the EEG-positions F7 and F8 and used a direct current of 1.5 mA. The 20-min stimulation was started during a 10-min break between acquisition and extinction and went on overall extinction-trials. The healthy participants were randomly assigned in two double-blinded process into two sham stimulation and two verum stimulation groups with opposite current flow directions. To measure the fear reactions, we used skin conductance responses (SCR and subjective ratings. We performed a generalized estimating equations model for the SCR to assess the impact of tDCS and current flow direction on extinction processes for all subjects that showed a successful conditioning (N = 84. The results indicate that tDCS accelerates early extinction processes with a significantly faster loss of CS+/CS– discrimination. The discrimination loss was driven by a significant decrease in reaction toward the CS+ as well as an increase in reaction toward the CS– in the tDCS verum groups, whereas the sham groups showed no significant reaction changes during this period. Therefore, we assume that tDCS of the vmPFC can be used to enhance early extinction processes successfully. But before it should be

Modulating activity in the prefrontal cortex changes decision-making for risky gains and losses: a transcranial direct current stimulation study.

Science.gov (United States)

Ye, Hang; Chen, Shu; Huang, Daqiang; Wang, Siqi; Luo, Jun

2015-06-01

When making choices under uncertainty, people usually consider both the risks and benefits of each option. Previous studies have found that weighing of risks and benefits during decision-making involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC), but the causal effect of this network on risk decision-making has remained unclear. This experiment was based on a risk-measurement table designed to provide a direct measure of risk preference, with a weighted value of the choices (denoted as weighted risk aversion, WRA) as an index of the participant's degree of risk aversion. We studied whether bifrontal transcranial direct current stimulation (tDCS) applied over the right and left prefrontal cortex can change the balance of risky vs. safe responses under both gain frame and loss frame. A total of 60 volunteers performed risk tasks while receiving either anodal over the right with cathodal over the left DLPFC, anodal over the left with cathodal over the right DLPFC, or sham stimulation. The participants tended to choose more risky options in the gain frame and more safe options in the loss frame after the right anodal/left cathodal tDCS. We also found that right anodal/left cathodal tDCS significantly decreased the WRA values compared with those associated with sham stimulation. These findings extend the notion that DLPFC activity is critical for risk decision-making, indicating an asymmetric role of the right DLPFC in the gain frame vs. the loss frame of risk decision-making. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly Sensitive Switchable Heterojunction Photodiode Based on Epitaxial Bi2FeCrO6 Multiferroic Thin Films.

Science.gov (United States)

Huang, Wei; Chakrabartty, Joyprokash; Harnagea, Catalin; Gedamu, Dawit; Ka, Ibrahima; Chaker, Mohamed; Rosei, Federico; Nechache, Riad

2018-04-18

Perovskite multiferroic oxides are promising materials for the realization of sensitive and switchable photodiodes because of their favorable band gap (heterojunction was fabricated by pulsed laser deposition. The heterojunction photodiode exhibits a large ideality factor ( n = ∼5.0) and a response time as fast as 68 ms, thanks to the effective charge carrier transport and collection at the BFCO/SRO interface. The diode can switch direction when the electric polarization is reversed by an external voltage pulse. The time-resolved photoluminescence decay of the device measured at ∼500 nm demonstrates an ultrafast charge transfer (lifetime = ∼6.4 ns) in BFCO/SRO heteroepitaxial structures. The estimated responsivity value at 500 nm and zero bias is 0.38 mA W -1 , which is so far the highest reported for any FE thin film photodiode. Our work highlights the huge potential for using multiferroic oxides to fabricate highly sensitive and switchable photodiodes.

Reverse engineering of an affinity-switchable molecular interaction characterized by atomic force microscopy single-molecule force spectroscopy.

Science.gov (United States)

Anselmetti, Dario; Bartels, Frank Wilco; Becker, Anke; Decker, Björn; Eckel, Rainer; McIntosh, Matthew; Mattay, Jochen; Plattner, Patrik; Ros, Robert; Schäfer, Christian; Sewald, Norbert

2008-02-19

Tunable and switchable interaction between molecules is a key for regulation and control of cellular processes. The translation of the underlying physicochemical principles to synthetic and switchable functional entities and molecules that can mimic the corresponding molecular functions is called reverse molecular engineering. We quantitatively investigated autoinducer-regulated DNA-protein interaction in bacterial gene regulation processes with single atomic force microscopy (AFM) molecule force spectroscopy in vitro, and developed an artificial bistable molecular host-guest system that can be controlled and regulated by external signals (UV light exposure and thermal energy). The intermolecular binding functionality (affinity) and its reproducible and reversible switching has been proven by AFM force spectroscopy at the single-molecule level. This affinity-tunable optomechanical switch will allow novel applications with respect to molecular manipulation, nanoscale rewritable molecular memories, and/or artificial ion channels, which will serve for the controlled transport and release of ions and neutral compounds in the future.

Modulation of electric brain responses evoked by pitch deviants through transcranial direct current stimulation.

Science.gov (United States)

Royal, Isabelle; Zendel, Benjamin Rich; Desjardins, Marie-Ève; Robitaille, Nicolas; Peretz, Isabelle

2018-01-31

Congenital amusia is a neurodevelopmental disorder, characterized by a difficulty detecting pitch deviation that is related to abnormal electrical brain responses. Abnormalities found along the right fronto-temporal pathway between the inferior frontal gyrus (IFG) and the auditory cortex (AC) are the likely neural mechanism responsible for amusia. To investigate the causal role of these regions during the detection of pitch deviants, we applied cathodal (inhibitory) transcranial direct current stimulation (tDCS) over right frontal and right temporal regions during separate testing sessions. We recorded participants' electrical brain activity (EEG) before and after tDCS stimulation while they performed a pitch change detection task. Relative to a sham condition, there was a decrease in P3 amplitude after cathodal stimulation over both frontal and temporal regions compared to pre-stimulation baseline. This decrease was associated with small pitch deviations (6.25 cents), but not large pitch deviations (200 cents). Overall, this demonstrates that using tDCS to disrupt regions around the IFG and AC can induce temporary changes in evoked brain activity when processing pitch deviants. These electrophysiological changes are similar to those observed in amusia and provide causal support for the connection between P3 and fronto-temporal brain regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation

Directory of Open Access Journals (Sweden)

Johannes eVosskuhl

2015-05-01

Full Text Available Working memory (WM and short-term memory (STM supposedly rely on the phase-amplitude coupling of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual’s memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS. To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N=33 were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG was measured before stimulation and analyzed with regard to the properties of phase-amplitude coupling between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity.

Differential effects of bihemispheric and unihemispheric transcranial direct current stimulation in young and elderly adults in verbal learning.

Science.gov (United States)

Fiori, Valentina; Nitsche, Michael; Iasevoli, Luigi; Cucuzza, Gabriella; Caltagirone, Carlo; Marangolo, Paola

2017-03-15

For the past few years, the potential of transcranial direct current stimulation (tDCS) for the treatment of several pathologies has been investigated. In the language domain, several studies, in healthy and brain-damaged populations, have already shown that tDCS is effective in enhancing naming, repetition and semantic word generation. In those studies, different tDCS electrode configurations have been tested, however, a direct comparison between different montages in verbal learning has never been conducted. In this study, we aimed to explore the impact of bihemispheric and unihemispheric tDCS on verbal learning task performance in two groups (young vs. elderly). Fifteen healthy volunteers participated per group. Each participant received three stimulation conditions: unihemispheric anodal tDCS over the left temporal area, bihemispheric tDCS over the left (anodal) and right (cathodal) temporal areas and a sham condition. During active stimulation, tDCS (20min, 2mA) was applied while each participant learned twenty pseudowords (arbitrarily assigned to corresponding pictures). No significant differences were found between the three conditions for the young group with regard to accuracy and vocal reaction times. In contrast, in the elderly group, real stimulation improved performance compared to sham but bihemispheric tDCS was more efficient than unilateral stimulation. These results suggest that bihemispheric stimulation is more effective in improving language learning but this effect is age-dependent. The hypothesis is advanced that cortical changes in the course of aging might differentially impact on tDCS efficacy on behavioral performance. These data may also have implications for treatment of stroke patients with language impairment. Copyright © 2017 Elsevier B.V. All rights reserved.

"I assumed that one was a placebo": exploring the consent process in a sham controlled acupressure trial.

Science.gov (United States)

Hughes, John Gareth; Russell, Wanda; Breckons, Matthew; Richardson, Janet; Lloyd-Williams, Mari; Molassiotis, Alex

2014-10-01

In clinical trials where participants are likely to be able to distinguish between true and sham interventions, informing participants that they may receive a sham intervention increases the likelihood of participants 'breaking the blind' and invalidating trial findings. The present study explored participants' perceptions of the consent process in a sham controlled acupressure trial which did not explicitly indicate participants may receive a sham intervention. Nested qualitative study within a randomised sham controlled trial of acupressure wristbands for chemotherapy-related nausea. Convenience sample of 26 patients participated in semi-structured interviews. Interviews were audio-recorded and transcribed verbatim. Transcripts analysed thematically using framework analysis. Study conducted within three geographical sites in the UK: Manchester, Liverpool, and Plymouth. All participants indicated that they believed they were fully informed when providing written consent to participate in the trial. Participants' perceived it was acceptable to employ a sham intervention within the trial of acupressure wristbands without informing potential participants that they may receive a sham treatment. Despite the fact that participants were not informed that one of the treatment arms was a sham intervention the majority indicated they assumed one of the treatment arms would be placebo. Many trials of acupuncture and acupressure do not inform participants they may receive a sham intervention. The current study indicates patients' perceive this approach to the consent process as acceptable. However, the fact participants assume one treatment may be placebo threatens the methodological basis for utilising this approach to the consent process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sensed presence and mystical experiences are predicted by suggestibility, not by the application of transcranial weak complex magnetic fields.

Science.gov (United States)

Granqvist, Pehr; Fredrikson, Mats; Unge, Patrik; Hagenfeldt, Andrea; Valind, Sven; Larhammar, Dan; Larsson, Marcus

2005-04-29

Transcranial magnetic stimulation (TMS) with weak (micro Tesla) complex waveform fields have been claimed to evoke the sensed presence of a sentient being in up to 80% in the general population. These findings have had a questionable neurophysiological foundation as the fields are approximately six orders of magnitude weaker than ordinary TMS fields. Also, no independent replication has been reported. To replicate and extend previous findings, we performed a double-blind experiment (N=89), with a sham-field control group. Personality characteristics indicating suggestibility (absorption, signs of abnormal temporal lobe activity, and a "new age"-lifestyle orientation) were used as predictors. Sensed presence, mystical, and other somatosensory experiences previously reported from the magnetic field stimulation were outcome measures. We found no evidence for any effects of the magnetic fields, neither in the entire group, nor in individuals high in suggestibility. Because the personality characteristics significantly predicted outcomes, suggestibility may account for previously reported effects. Our results strongly question the earlier claims of experiential effects of weak magnetic fields.

Differential effects of 10-Hz and 40-Hz transcranial alternating current stimulation (tACS) on endogenous versus exogenous attention.

Science.gov (United States)

Hopfinger, Joseph B; Parsons, Jonathan; Fröhlich, Flavio

2017-04-01

Previous electrophysiological studies implicate both alpha (8-12 Hz) and gamma (>30 Hz) neural oscillations in the mechanisms of selective attention. Here, participants preformed two separate visual attention tasks, one endogenous and one exogenous, while transcranial alternating current stimulation (tACS), at 10 Hz, 40 Hz, or sham, was applied to the right parietal lobe. Our results provide new evidence for the roles of gamma and alpha oscillations in voluntary versus involuntary shifts of attention. Gamma (40 Hz) stimulation resulted in improved disengagement from invalidly cued targets in the endogenous attention task, whereas alpha stimulation (10 Hz) had no effect on endogenous attention, but increased the exogenous cuing effect. These findings agree with previous studies suggesting that right inferior parietal regions may be especially important for the disengagement of attention, and go further to provide details about the specific type of oscillatory neural activity within that brain region that is differentially involved in endogenous versus exogenous attention. Our results also have potential implications for the plasticity and training of attention systems.

Poisson equation in the Kohn-Sham Coulomb problem

OpenAIRE

Manby, F. R.; Knowles, Peter James

2001-01-01

We apply the Poisson equation to the quantum mechanical Coulomb problem for many-particle systems. By introducing a suitable basis set, the two-electron Coulomb integrals become simple overlaps. This offers the possibility of very rapid linear-scaling treatment of the Coulomb contribution to Kohn-Sham theory.

Brazilian Guidelines for transcranial doppler in children and adolescents with sickle cell disease

Directory of Open Access Journals (Sweden)

Clarisse Lopes de Castro Lobo

2011-02-01

Full Text Available BACKGROUND: Sickle cell disease is the most common monogenic hereditary disease in Brazil. Although strokes are one of the main causes of morbidity and mortality in these patients, the use of transcranial Doppler to identify children at risk is not universally used. OBJECTIVE: To develop Brazilian guidelines for the use of transcranial Doppler in sickle cell disease children and adolescents, so that related health policies can be expanded, and thus contribute to reduce morbidity and mortality. METHODS: The guidelines were formulated in a consensus meeting of experts in transcranial Doppler and sickle cell disease. The issues discussed were previously formulated and scientific articles in databases (MEDLINE, SciELO and Cochrane were carefully analyzed. The consensus for each question was obtained by a vote of experts on the specific theme. RESULTS: Recommendations were made, including indications for the use of transcranial Doppler according to the sickle cell disease genotype and patients age; the necessary conditions to perform the exam and its periodicity depending on exam results; the criteria for the indication of blood transfusions and iron chelation therapy; the indication of hydroxyurea; and the therapeutic approach in cases of conditional transcranial Doppler. CONCLUSION: The Brazilian guidelines on the use of transcranial doppler in sickle cell disease patients may reduce the risk of strokes, and thus reduce the morbidity and mortality and improve the quality of life of sickle cell disease patients.

Junk science for sale Sham journals proliferating online.

Science.gov (United States)

Klyce, Walter; Feller, Edward

2017-07-05

A new danger threatens the integrity of scholarly publishing: predatory journals. Internet-only, "open-access" publishing is a valid way for researchers to reach the public without a paywall separating them. But, of thousands of open-access scientific journals today, as many as twenty-five percent are believed to be fake, existing only to make money by charging authors high processing fees. In sham journals, peer review is cursory or absent: as many as eighty to ninety percent of submitted manuscripts are accepted, many within days, without any editorial comment. Predatory journalism can be remarkably good at mimicking reputable publishers. Sham journals use names and logos that closely resemble those of legitimate journals, intentionally confusing site visitors. Untrustworthy publications have not received the widespread, damning publicity they deserve. If junk science is not confronted and eliminated, it will continue to tarnish and undermine ethical, open-access scholarly publishing. [Full article available at http://rimed.org/rimedicaljournal-2017-07.asp].

Smart window using a thermally and optically switchable liquid crystal cell

Science.gov (United States)

Oh, Seung-Won; Kim, Sang-Hyeok; Baek, Jong-Min; Yoon, Tae-Hoon

2018-02-01

Light shutter technologies that can control optical transparency have been studied extensively for developing curtain-free smart windows. We introduce thermally and optically switchable light shutters using LCs doped with push-pull azobenzene, which is known to speed up thermal relaxation. The liquid crystal light shutter can be switched between translucent and transparent states or transparent and opaque states by phase transition through changing temperature or photo-isomerization of doped azobenzene. The liquid crystal light shutter can be used for privacy windows with an initial translucent state or energy-saving windows with an initial transparent state.

Safety Parameter Considerations of Anodal Transcranial Direct Current Stimulation in Rats

Science.gov (United States)

2017-10-01

Richardson, J.D., Baker, J.M., Rorden, C., 2011. Transcranial direct current stimulation improves naming reaction time in fluent aphasia: a...AFRL-RH-WP-TR-2017-0069 Safety parameter considerations of anodal transcranial Direct Current Stimulation in rats R. Andy McKinley...response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the

Kohn–Sham exchange-correlation potentials from second-order reduced density matrices

Energy Technology Data Exchange (ETDEWEB)

Cuevas-Saavedra, Rogelio; Staroverov, Viktor N., E-mail: vstarove@uwo.ca [Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7 (Canada); Ayers, Paul W. [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1 (Canada)

2015-12-28

We describe a practical algorithm for constructing the Kohn–Sham exchange-correlation potential corresponding to a given second-order reduced density matrix. Unlike conventional Kohn–Sham inversion methods in which such potentials are extracted from ground-state electron densities, the proposed technique delivers unambiguous results in finite basis sets. The approach can also be used to separate approximately the exchange and correlation potentials for a many-electron system for which the reduced density matrix is known. The algorithm is implemented for configuration-interaction wave functions and its performance is illustrated with numerical examples.

Borophene as a Promising Material for Charge-Modulated Switchable CO2 Capture.

Science.gov (United States)

Tan, Xin; Tahini, Hassan A; Smith, Sean C

2017-06-14

Ideal carbon dioxide (CO 2 ) capture materials for practical applications should bind CO 2 molecules neither too weakly to limit good loading kinetics nor too strongly to limit facile release. Although charge-modulated switchable CO 2 capture has been proposed to be a controllable, highly selective, and reversible CO 2 capture strategy, the development of a practical gas-adsorbent material remains a great challenge. In this study, by means of density functional theory (DFT) calculations, we have examined the possibility of conductive borophene nanosheets as promising sorbent materials for charge-modulated switchable CO 2 capture. Our results reveal that the binding strength of CO 2 molecules on negatively charged borophene can be significantly enhanced by injecting extra electrons into the adsorbent. At saturation CO 2 capture coverage, the negatively charged borophene achieves CO 2 capture capacities up to 6.73 × 10 14 cm -2 . In contrast to the other CO 2 capture methods, the CO 2 capture/release processes on negatively charged borophene are reversible with fast kinetics and can be easily controlled via switching on/off the charges carried by borophene nanosheets. Moreover, these negatively charged borophene nanosheets are highly selective for separating CO 2 from mixtures with CH 4 , H 2 , and/or N 2 . This theoretical exploration will provide helpful guidance for identifying experimentally feasible, controllable, highly selective, and high-capacity CO 2 capture materials with ideal thermodynamics and reversibility.

Diagnostic Use of Transcranial Magnetic Stimulation in Psychiatry

Directory of Open Access Journals (Sweden)

Abdullah Bolu

2013-08-01

Full Text Available Motor evoked potentials from peripheral nerves, spinal cord or muscle can be recorded by stimulation of the motor cortex and motor pathways in the central nervous system with transcranial magnetic stimulation which is a neurophysiological analysis method. This method allows investigation the mechanism of diseases which cause changes in the excitability of cortical motor areas. Similarly, it was used in determining the effects of psychotropic drugs on cortical activity and electrophysiological measurement of aggressive behavior Transcranial magnetic stimulation studies in the field of psychiatry are focused on etiopathogenesis of pathologies such as schizophrenia, obsessive-compulsive disorder, attention deficit hyperactivity disorder and substance abuse.

Feasibility of transcranial direct current stimulation use in children aged 5 to 12 years.

Science.gov (United States)

Andrade, Agnes Carvalho; Magnavita, Guilherme Moreira; Allegro, Juleilda Valéria Brasil Nunes; Neto, Carlos Eduardo Borges Passos; Lucena, Rita de Cássia Saldanha; Fregni, Felipe

2014-10-01

Transcranial direct current stimulation is a noninvasive brain stimulation technique that has been studied for the treatment of neuropsychiatric disorders in adults, with minimal side effects. The objective of this study is to report the feasibility, tolerability, and the short-term adverse effects of transcranial direct current stimulation in children from 5 to 12 years of age. It is a naturalistic study of 14 children who underwent 10 sessions of transcranial direct current stimulation as an alternative, off-label, and open-label treatment for various languages disorders. Frequency, intensity, adverse effects, and perception of improvement reported by parents were collected. The main side effects detected were tingling (28.6%) and itching (28.6%), acute mood changes (42.9%), and irritability (35.7%). Transcranial direct current stimulation is a feasible and tolerable technique in children, although studies regarding plastic and cognitive changes in children are needed to confirm its safety. In conclusion, this is a naturalistic report in which we considered transcranial direct current stimulation as feasible in children. © The Author(s) 2013.

A Switchable Linker-Based Immunoassay for Ultrasensitive Visible Detection of Salmonella in Tomatoes.

Science.gov (United States)

Hahn, Jungwoo; Kim, Eunghee; You, Young Sang; Gunasekaran, Sundaram; Lim, Seokwon; Choi, Young Jin

2017-10-01

On-site detection for sensitive identification of foodborne pathogens on fresh produce with minimal use of specialized instrumentation is crucial to the food industry. A switchable linker (SL)-based immunoassay was designed for ultrasensitive on-site detection of Salmonella in tomato samples. The assay is based on large-scale aggregation of gold nanoparticles (GNPs), induced by a quantitative relationship among the biotinylated Salmonella polyclonal antibody (b-Ab) used as the SL, the functionalized GNPs, and Salmonella. Important factors such as the concentration of SLs, time required for large-scale aggregation, and selectivity of b-Ab were optimized to minimize the detection time (within 45 min with gentle agitation) and achieve the lowest limit of detection (LOD; 10 CFU/g in tomato samples) possible. This SL-based immunoassay with its relatively low LOD and short detection time may meet the need for rapid, simple, on-site analysis of pathogens in fresh produce. The novel switchable linker-based immunoassay is a rapid, specific, and sensitive method that has potential applications for routine diagnostics of Salmonella in tomato products. These advantages make it a practical approach for general use in the processing industry to detect Salmonella rapidly and to implement appropriate regulatory procedures. Furthermore, it could be applied to other fresh products including cantaloupe, strawberry, and cucumbers. © 2017 Institute of Food Technologists®.

A ferroelectric switchable tunnel junction: KNbO{sub 3}/SrTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Rahmanizadeh, Kourosh; Bihlmayer, Gustav; Wortmann, Daniel; Bluegel, Stefan [Peter Gruenberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Juelich and JARA, 52425 Juelich (Germany)

2012-07-01

The properties of thin oxide films and multilayers are strongly influenced by defects and, therefore, can be controllably tuned by the defect concentration at the interface. For example, due to the charge discontinuity at the SrTiO{sub 3}/KO-KNbO{sub 3}-NbO{sub 2}/SrTiO{sub 3} interface only one direction of polarization in KNbO{sub 3} film is stable. A switchable polarization in KNbO{sub 3} can be realized by creating (oxygen) defects at the interfaces. We carried out density functional theory (DFT) calculations based on the full potential linearized augmented planewave (FLAPW) method as implemented in the FLEUR code for studying the polar interface SrTiO{sub 3}/KNbO{sub 3} and a SrRuO{sub 3}/SrTiO{sub 3}/KNbO{sub 3} tunnel junction. The electronic transport properties of the switchable multiferroic SrRuO{sub 3}/SrTiO{sub 3}/KO-KNbO{sub 3}-NbO{sub 3}/SrTiO{sub 3}/SrRuO{sub 3} heterostructure have been investigated using an embedded Green-function approach. A strong dependence of the (magneto electric) transport properties on the polarization is observed.

Bioinspired Layer-by-Layer Microcapsules Based on Cellulose Nanofibers with Switchable Permeability

DEFF Research Database (Denmark)

Paulraj, Thomas; Riazanova, Anastasia V; Yao, Kun

2017-01-01

Green, all-polysaccharide based microcapsules with mechanically robust capsule walls and fast, stimuli-triggered, and switchable permeability behavior show great promise in applications based on selective and timed permeability. Taking a cue from nature, the build-up and composition of plant......-by-layer technique on sacrificial CaCO3 templates, using plant polysaccharides (pectin, cellulose nanofibers, and xyloglucan) only. In water, the capsule wall was permeable to labeled dextrans with a hydrodynamic diameter of ∼6.6 nm. Upon exposure to NaCl, the porosity of the capsule wall quickly changed allowing...

A Pilot Study of EEG Source Analysis Based Repetitive Transcranial Magnetic Stimulation for the Treatment of Tinnitus.

Directory of Open Access Journals (Sweden)

Hui Wang

Full Text Available Repetitive Transcranial Magnetic Stimulation (rTMS is a novel therapeutic tool to induce a suppression of tinnitus. However, the optimal target sites are unknown. We aimed to determine whether low-frequency rTMS induced lasting suppression of tinnitus by decreasing neural activity in the cortex, navigated by high-density electroencephalogram (EEG source analysis, and the utility of EEG for targeting treatment.In this controlled three-armed trial, seven normal hearing patients with tonal tinnitus received a 10-day course of 1-Hz rTMS to the cortex, navigated by high-density EEG source analysis, to the left temporoparietal cortex region, and to the left temporoparietal with sham stimulation. The Tinnitus handicap inventory (THI and a visual analog scale (VAS were used to assess tinnitus severity and loudness. Measurements were taken before, and immediately, 2 weeks, and 4 weeks after the end of the interventions.Low-frequency rTMS decreased tinnitus significantly after active, but not sham, treatment. Responders in the EEG source analysis-based rTMS group, 71.4% (5/7 patients, experienced a significant reduction in tinnitus loudness, as evidenced by VAS scores. The target site of neuronal generators most consistently associated with a positive response was the frontal lobe in the right hemisphere, sourced using high-density EEG equipment, in the tinnitus patients. After left temporoparietal rTMS stimulation, 42.8% (3/7 patients experienced a decrease in tinnitus loudness.Active EEG source analysis based rTMS resulted in significant suppression in tinnitus loudness, showing the superiority of neuronavigation-guided coil positioning in dealing with tinnitus. Non-auditory areas should be considered in the pathophysiology of tinnitus. This knowledge in turn can contribute to investigate the pathophysiology of tinnitus.

Controlling the Anchoring Effect through Transcranial Direct Current Stimulation (tDCS to the Right Dorsolateral Prefrontal Cortex

Directory of Open Access Journals (Sweden)

Jianbiao Li

2017-06-01

Full Text Available Selective accessibility mechanisms indicate that anchoring effects are results of selective retrieval of working memory. Neuroimaging studies have revealed that the right dorsolateral prefrontal cortex (DLPFC is closely related to memory retrieval and performance. However, no research has investigated the effect of changing the cortical excitability in right DLPFC on anchoring effects. Transcranial direct current stimulation (tDCS can modulate the excitability of the human cerebral cortex, while anodal and cathodal tDCS are postulated to increase or decrease cortical activity, respectively. In this study, we used tDCS to investigate whether effects of increased or decreased right DLPFC excitability influence anchoring effects in willingness to pay (WTP experiments. Ninety participants were first randomly assigned to receive either anodal, cathodal, or sham stimulation of 15 min, then they performed a valuation task regarding WTP. The results showed that anchoring effects were negatively related to activities of right DLPFC: the anodal stimulation diminished anchoring effects while the cathodal stimulation increased anchoring effects. These outcomes provide one of the first instances of neural evidence for the role of the right DLPFC in anchoring effects and support psychological explanations of the selective accessibility mechanisms and cognitive sets.

Transcranial Direct Current Stimulation in Tinnitus Patients: A Systemic Review and Meta-Analysis

Directory of Open Access Journals (Sweden)

Jae-Jin Song

2012-01-01

Full Text Available Although transcranial direct current stimulation (tDCS has already been used to manage tinnitus patients, paucity of reports and variations in protocols preclude a comprehensive understanding. Hence, we conducted a meta-analysis based on systemic review to assess effectiveness of tDCS in tinnitus management and to compare stimulation parameters. PubMed was searched for tDCS studies in tinnitus. For randomized controlled trials (RCTs, a meta-analysis was performed. A total of 17 studies were identified and 6 of them were included in the systemic review and 2 RCTs were included in the meta-analysis. Overall 39.5% responded to active tDCS with a mean tinnitus intensity reduction of 13.5%. Additionally, left temporal area (LTA and bifrontal tDCS indicated comparable results. Active tDCS was found to be more effective than sham tDCS for tinnitus intensity reduction (Hedges' g=.77, 95% confidence interval 0.23–1.31. The efficacy of tDCS in tinnitus could not be fully confirmed by the current study because of the limited number of studies, but all studies included in the current systemic review and meta-analysis demonstrated significant tinnitus intensity improvement. Therefore, tDCS may be a promising tool for tinnitus management. Future RCTs in a large series regarding the efficacy as well as the comparison between LTA- and bifrontal tDCS are recommended.

Effect of Parkinson's Disease in Transcranial Magnetic Stimulation Treatment

Science.gov (United States)

Syeda, Farheen; Magsood, Hamzah; Lee, Erik; El-Gendy, Ahmed; Jiles, David; Hadimani, Ravi

Transcranial Magnetic Stimulation is a non-invasive clinical therapy used to treat depression and migraine, and shows further promise as treatment for Parkinson's disease, Alzheimer's disease, and other neurological disorders. However, it is yet unclear as to how anatomical differences may affect stimulation from this treatment. We use finite element analysis to model and analyze the results of Transcranial Magnetic Stimulation in various head models. A number of heterogeneous head models have been developed using MRI data of real patients, including healthy individuals as well as patients of Parkinson's disease. Simulations of Transcranial Magnetic Stimulation performed on 22 anatomically different models highlight the differences in induced stimulation. A standard Figure of 8 coil is used with frequency 2.5 kHz, placed 5 mm above the head. We compare cortical stimulation, volume of brain tissue stimulated, specificity, and maximum E-field induced in the brain for models ranging from ages 20 to 60. Results show that stimulation varies drastically between patients of the same age and health status depending upon brain-scalp distance, which is not necessarily a linear progression with age.

Global perception depends on coherent work of bilateral visual cortices: transcranial magnetic stimulation (TMS) studies.

Science.gov (United States)

Zhang, Xin; Han, ShiHui

2007-08-01

Previous research suggests that the right and left hemispheres dominate global and local perception of hierarchical patterns, respectively. The current work examined whether global perception of hierarchical stimuli requires coherent work of bilateral visual cortices using transcranial magnetic stimulation (TMS). Subjects discriminated global or local properties of compound letters in Experiment 1. Reaction times were recorded when single-pulse real TMS or sham TMS was delivered over the left or right visual cortex. While a global precedence effect (i.e., faster responses to global than local targets and stronger global-to-local interference than the reverse) was observed, TMS decreased global-to-local interference whereas increased local-to-global interference. Experiment 2 ruled out the possibility that the effects observed in Experiment 1 resulted from perceptual learning. Experiment 3 used compound shapes and observed TMS effect similar to that in Experiment 1. Moreover, TMS also slowed global RTs whereas speeded up local RTs in Experiment 3. Finally, the TMS effects observed in Experiments 1 and 3 did not differ between the conditions when TMS was applied over the left and right hemispheres. The results support a coherence hypothesis that global perception of compound stimuli depends upon the coherent work of bilateral visual cortices.

pH-switchable electrochemical sensing platform based on chitosan-reduced graphene oxide/concanavalin a layer for assay of glucose and urea.

Science.gov (United States)

Song, Yonghai; Liu, Hongyu; Tan, Hongliang; Xu, Fugang; Jia, Jianbo; Zhang, Lixue; Li, Zhuang; Wang, Li

2014-02-18

A facile and effective electrochemical sensing platform for the detection of glucose and urea in one sample without separation was developed using chitosan-reduced graphene oxide (CS-rGO)/concanavalin A (Con A) as a sensing layer. The CS-rGO/Con A with pH-dependent surface net charges exhibited pH-switchable response to negatively charged Fe(CN)6(3-). The principle for glucose and urea detection was essentially based on in situ pH-switchable enzyme-catalyzed reaction in which the oxidation of glucose catalyzed by glucose oxidase or the hydrolyzation of urea catalyzed by urease resulted in a pH change of electrolyte solution to give different electrochemical responses toward Fe(CN)6(3-). It was verified by cyclic voltammograms, differential pulse voltammograms, and electrochemical impedance spectroscopy. The resistance to charge transfer or amperometric current changed proportionally toward glucose concentration from 1.0 to 10.0 mM and urea concentration from 1.0 to 7.0 mM. On the basis of human serum experiments, the sensing platform was proved to be suitable for simultaneous assay of glucose and urea in a practical biosystem. This work not only gives a way to detect glucose and urea in one sample without separation but also provides a potential strategy for the detection of nonelectroactive species based on the enzyme-catalyzed reaction and pH-switchable biosensor.

Local-scaling transformations and the direct determination of Kohn--Sham orbitals and potentials for beryllium

International Nuclear Information System (INIS)

Ludena, E.V.; Maldonado, J.; Lopez-Boada, R.; Koga, T.; Kryachko, E.S.

1995-01-01

Local-scaling transformations are used in the present work to obtain accurate Kohn--Sham 1s and 2s orbitals for the beryllium atom by means of a density-constrained variation of the single-determinant kinetic energy functional. An analytic representation of these Kohn--Sham orbitals is given and the quality of the different types of orbitals generated is discussed with particular reference to their kinetic energy and momenta mean values. In addition, we determine the effective Kohn--Sham potential and analyze it in terms of its exchange-only and correlation contributions

Ferroelectric based catalysis: Switchable surface chemistry

Science.gov (United States)

Kakekhani, Arvin; Ismail-Beigi, Sohrab

2015-03-01

We describe a new class of catalysts that uses an epitaxial monolayer of a transition metal oxide on a ferroelectric substrate. The ferroelectric polarization switches the surface chemistry between strongly adsorptive and strongly desorptive regimes, circumventing difficulties encountered on non-switchable catalytic surfaces where the Sabatier principle dictates a moderate surface-molecule interaction strength. This method is general and can, in principle, be applied to many reactions, and for each case the choice of the transition oxide monolayer can be optimized. Here, as a specific example, we show how simultaneous NOx direct decomposition (into N2 and O2) and CO oxidation can be achieved efficiently on CrO2 terminated PbTiO3, while circumventing oxygen (and sulfur) poisoning issues. One should note that NOx direct decomposition has been an open challenge in automotive emission control industry. Our method can expand the range of catalytically active elements to those which are not conventionally considered for catalysis and which are more economical, e.g., Cr (for NOx direct decomposition and CO oxidation) instead of canonical precious metal catalysts. Primary support from Toyota Motor Engineering and Manufacturing, North America, Inc.

Transcranial direct current stimulation for motor recovery of upper limb function after stroke.

Science.gov (United States)

Lüdemann-Podubecká, Jitka; Bösl, Kathrin; Rothhardt, Sandra; Verheyden, Geert; Nowak, Dennis Alexander

2014-11-01

Changes in neural processing after stroke have been postulated to impede recovery from stroke. Transcranial direct current stimulation has the potential to alter cortico-spinal excitability and thereby might be beneficial in stroke recovery. We review the pertinent literature prior to 30/09/2013 on transcranial direct current stimulation in promoting motor recovery of the affected upper limb after stroke. We found overall 23 trials (they included 523 participants). All stimulation protocols pride on interhemispheric imbalance model. In a comparative approach, methodology and effectiveness of (a) facilitation of the affected hemisphere, (b) inhibition of the unaffected hemisphere and (c) combined application of transcranial direct current stimulation over the affected and unaffected hemispheres to treat impaired hand function after stroke are presented. Transcranial direct current stimulation is associated with improvement of the affected upper limb after stroke, but current evidence does not support its routine use. Copyright © 2014 Elsevier Ltd. All rights reserved.

Transcranial stimulability of phosphenes by long lightning electromagnetic pulses

International Nuclear Information System (INIS)

Peer, J.; Kendl, A.

2010-01-01

The electromagnetic pulses of rare long (order of seconds) repetitive lightning discharges near strike point (order of 100 m) are analyzed and compared to magnetic fields applied in standard clinical transcranial magnetic stimulation (TMS) practice. It is shown that the time-varying lightning magnetic fields and locally induced electric fields are in the same order of magnitude and frequency as those established in TMS experiments to study stimulated perception phenomena, like magnetophosphenes. Lightning electromagnetic pulse induced transcranial magnetic stimulation of phosphenes in the visual cortex is concluded to be a plausible interpretation of a large class of reports on luminous perceptions during thunderstorms.

Transcranial stimulability of phosphenes by long lightning electromagnetic pulses

Energy Technology Data Exchange (ETDEWEB)

Peer, J. [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria); Kendl, A., E-mail: alexander.kendl@uibk.ac.a [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria)

2010-06-28

The electromagnetic pulses of rare long (order of seconds) repetitive lightning discharges near strike point (order of 100 m) are analyzed and compared to magnetic fields applied in standard clinical transcranial magnetic stimulation (TMS) practice. It is shown that the time-varying lightning magnetic fields and locally induced electric fields are in the same order of magnitude and frequency as those established in TMS experiments to study stimulated perception phenomena, like magnetophosphenes. Lightning electromagnetic pulse induced transcranial magnetic stimulation of phosphenes in the visual cortex is concluded to be a plausible interpretation of a large class of reports on luminous perceptions during thunderstorms.

Imaging the functional connectivity of the Periaqueductal Gray during genuine and sham electroacupuncture treatment

Directory of Open Access Journals (Sweden)

Tu Peichi

2010-11-01

Full Text Available Abstract Background Electroacupuncture (EA is currently one of the most popular acupuncture modalities. However, the continuous stimulation characteristic of EA treatment presents challenges to the use of conventional functional Magnetic Resonance Imaging (fMRI approaches for the investigation of neural mechanisms mediating treatment response because of the requirement for brief and intermittent stimuli in event related or block designed task paradigms. A relatively new analysis method, functional connectivity fMRI (fcMRI, has great potential for studying continuous treatment modalities such as EA. In a previous study, we found that, compared with sham acupuncture, EA can significantly reduce Periaqueductal Gray (PAG activity when subsequently evoked by experimental pain. Given the PAG's important role in mediating acupuncture analgesia, in this study we investigated functional connectivity with the area of the PAG we previously identified and how that connectivity was affected by genuine and sham EA. Results Forty-eight subjects, who were randomly assigned to receive either genuine or sham EA paired with either a high or low expectancy manipulation, completed the study. Direct comparison of each treatment mode's functional connectivity revealed: significantly greater connectivity between the PAG, left posterior cingulate cortex (PCC, and precuneus for the contrast of genuine minus sham; significantly greater connectivity between the PAG and right anterior insula for the contrast of sham minus genuine; no significant differences in connectivity between different contrasts of the two expectancy levels. Conclusions Our findings indicate the intrinsic functional connectivity changes among key brain regions in the pain matrix and default mode network during genuine EA compared with sham EA. We speculate that continuous genuine EA stimulation can modify the coupling of spontaneous activity in brain regions that play a role in modulating pain

Beta band transcranial alternating (tACS and direct current stimulation (tDCS applied after initial learning facilitate retrieval of a motor sequence

Directory of Open Access Journals (Sweden)

Vanessa eKrause

2016-01-01

Full Text Available The primary motor cortex (M1 contributes to the acquisition and early consolidation of a motor sequence. Although the relevance of M1 excitability for motor learning has been supported, the significance of M1 oscillations remains an open issue. This study aims at investigating to what extent retrieval of a newly learned motor sequence can be differentially affected by motor-cortical transcranial alternating (tACS and direct current stimulation (tDCS. Alpha (10 Hz, beta (20 Hz or sham tACS was applied in 36 right-handers. Anodal or cathodal tDCS was applied in 30 right-handers. Participants learned an eight-digit serial reaction time task (SRTT; sequential vs. random with the right hand. Stimulation was applied to the left M1 after SRTT acquisition at rest for ten minutes. Reaction times were analyzed at baseline, end of acquisition, retrieval immediately after stimulation and reacquisition after eight further sequence repetitions.Reaction times during retrieval were significantly faster following 20 Hz tACS as compared to 10 Hz and sham tACS indicating a facilitation of early consolidation. TDCS yielded faster reaction times, too, independent of polarity. No significant differences between 20 Hz tACS and tDCS effects on retrieval were found suggesting that 20 Hz effects might be associated with altered motor-cortical excitability. Based on the behavioural modulation yielded by tACS and tDCS one might speculate that altered motor-cortical beta oscillations support early motor consolidation possibly associated with neuroplastic reorganization.

Switchable multi-wavelength erbium-doped fiber ring laser based on a tapered in-line Mach–Zehnder interferometer

Science.gov (United States)

Zhou, Yuxin; Wang, Xin; Tang, Zijuan; Lou, Shuqin

2018-05-01

In this paper, a switchable multi-wavelength erbium-doped fiber ring laser based on a tapered in-line Mach–Zehnder interferometer is proposed. The in-line Mach–Zehnder interferometer is fabricated by splicing a large-core fiber between two segments of single mode fibers, in which the first splicing point is tapered and the second splicing point is connected directly. By carefully rotating the polarization controller, switchable single-, dual-, triple- and quad-wavelength lasing outputs can be obtained with a side mode suppression ratio higher than 50 dB. The maximal peak power difference of multi-wavelength lasing is 3.67 dB, demonstrating a good power equalization performance. Furthermore, the proposed laser is proven to be very stable at room temperature. The wavelength shifts and peak power fluctuations are less than 0.02 nm and 1.3 dB over half an hour. In addition, stable quintuple-wavelength lasing with a side mode suppression ratio higher than 50 dB can also be realized when the filter length is changed.

Transcranial radiograph and magnetic resonance imaging in the evaluation of osseous changes of the temporomandibular joint

International Nuclear Information System (INIS)

Cho, Soo Beom; Koh, Kwang Joon

2002-01-01

To evaluate the diagnostic accuracy of transcranial radiographs and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) in the assessment of osseous changes of the condylar head and articular eminence. Osseous changes of the TMJ were evaluated in forty-three patients. Osseous changes of the condylar head and articular eminence were observed in 41 joints and 64 joints, respectively on transcranial radiographs, and 48 joints and 59 joints, respectively on MRI. The flattening, sclerosis, erosion, and osteophyte formation of the condylar heads were observed in 36.6%, 43.9%, 12.2%, and 7.3%, respectively on transcranial radiographs compared with 35.4%, 20.8%, 37.5%, and 6.3%, respectively on MRI. While, the flattening, sclerosis, and erosion of the articular eminences were observed in 26.6%, 67.2%, and 6.2%, respectively on transcranial radiographs compared with 32.2%, 59.3%, and 8.5%, respectively on MRI. There were no statistical differences between transcranial radiographs and MRI scans in the detection of osseous changes of the TMJ. However, MRI scans were superior to the transcranial radiographs in the detection of erosion of the condylar head (p<0.01).

Transcranial radiograph and magnetic resonance imaging in the evaluation of osseous changes of the temporomandibular joint

Energy Technology Data Exchange (ETDEWEB)

Cho, Soo Beom; Koh, Kwang Joon [School of Dentistry, Chonbuk National University, Chonju (Korea, Republic of)

2002-06-15

To evaluate the diagnostic accuracy of transcranial radiographs and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) in the assessment of osseous changes of the condylar head and articular eminence. Osseous changes of the TMJ were evaluated in forty-three patients. Osseous changes of the condylar head and articular eminence were observed in 41 joints and 64 joints, respectively on transcranial radiographs, and 48 joints and 59 joints, respectively on MRI. The flattening, sclerosis, erosion, and osteophyte formation of the condylar heads were observed in 36.6%, 43.9%, 12.2%, and 7.3%, respectively on transcranial radiographs compared with 35.4%, 20.8%, 37.5%, and 6.3%, respectively on MRI. While, the flattening, sclerosis, and erosion of the articular eminences were observed in 26.6%, 67.2%, and 6.2%, respectively on transcranial radiographs compared with 32.2%, 59.3%, and 8.5%, respectively on MRI. There were no statistical differences between transcranial radiographs and MRI scans in the detection of osseous changes of the TMJ. However, MRI scans were superior to the transcranial radiographs in the detection of erosion of the condylar head (p<0.01).

Safety and feasibility of transcranial direct current stimulation (tDCS) combined with sensorimotor retraining in chronic low back pain: a protocol for a pilot randomised controlled trial.

Science.gov (United States)

Ouellette, Adam Louis; Liston, Matthew B; Chang, Wei-Ju; Walton, David M; Wand, Benedict Martin; Schabrun, Siobhan M

2017-08-21

Chronic low back pain (LBP) is a common and costly health problem yet current treatments demonstrate at best, small effects. The concurrent application of treatments with synergistic clinical and mechanistic effects may improve outcomes in chronic LBP. This pilot trial aims to (1) determine the feasibility, safety and perceived patient response to a combined transcranial direct current stimulation (tDCS) and sensorimotor retraining intervention in chronic LBP and (2) provide data to support a sample size calculation for a fully powered trial should trends of effectiveness be present. A pilot randomised, assessor and participant-blind, sham-controlled trial will be conducted. Eighty participants with chronic LBP will be randomly allocated to receive either (1) active tDCS + sensorimotor retraining or (2) sham tDCS + sensorimotor retraining. tDCS (active or sham) will be applied to the primary motor cortex for 20 min immediately prior to 60 min of supervised sensorimotor retraining twice per week for 10 weeks. Participants in both groups will complete home exercises three times per week. Feasibility, safety, pain, disability and pain system function will be assessed immediately before and after the 10-week intervention. Analysis of feasibility and safety will be performed using descriptive statistics. Statistical analyses will be conducted based on intention-to-treat and per protocol and will be used to determine trends for effectiveness. Ethical approval has been gained from the institutional human research ethics committee (H10184). Written informed consent will be provided by all participants. Results from this pilot study will be submitted for publication in peer-reviewed journals. ACTRN12616000624482. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Test-retest reliability of prefrontal transcranial Direct Current Stimulation (tDCS) effects on functional MRI connectivity in healthy subjects.

Science.gov (United States)

Wörsching, Jana; Padberg, Frank; Helbich, Konstantin; Hasan, Alkomiet; Koch, Lena; Goerigk, Stephan; Stoecklein, Sophia; Ertl-Wagner, Birgit; Keeser, Daniel

2017-07-15

Transcranial Direct Current Stimulation (tDCS) of the prefrontal cortex (PFC) can be used for probing functional brain connectivity and meets general interest as novel therapeutic intervention in psychiatric and neurological disorders. Along with a more extensive use, it is important to understand the interplay between neural systems and stimulation protocols requiring basic methodological work. Here, we examined the test-retest (TRT) characteristics of tDCS-induced modulations in resting-state functional-connectivity MRI (RS fcMRI). Twenty healthy subjects received 20minutes of either active or sham tDCS of the dorsolateral PFC (2mA, anode over F3 and cathode over F4, international 10-20 system), preceded and ensued by a RS fcMRI (10minutes each). All subject underwent three tDCS sessions with one-week intervals in between. Effects of tDCS on RS fcMRI were determined at an individual as well as at a group level using both ROI-based and independent-component analyses (ICA). To evaluate the TRT reliability of individual active-tDCS and sham effects on RS fcMRI, voxel-wise intra-class correlation coefficients (ICC) of post-tDCS maps between testing sessions were calculated. For both approaches, results revealed low reliability of RS fcMRI after active tDCS (ICC (2,1) = -0.09 - 0.16). Reliability of RS fcMRI (baselines only) was low to moderate for ROI-derived (ICC (2,1) = 0.13 - 0.50) and low for ICA-derived connectivity (ICC (2,1) = 0.19 - 0.34). Thus, for ROI-based analyses, the distribution of voxel-wise ICC was shifted to lower TRT reliability after active, but not after sham tDCS, for which the distribution was similar to baseline. The intra-individual variation observed here resembles variability of tDCS effects in motor regions and may be one reason why in this study robust tDCS effects at a group level were missing. The data can be used for appropriately designing large scale studies investigating methodological issues such as sources of variability and

How does transcranial DC stimulation of the primary motor cortex alter regional neuronal activity in the human brain?

Science.gov (United States)

Lang, Nicolas; Siebner, Hartwig R; Ward, Nick S; Lee, Lucy; Nitsche, Michael A; Paulus, Walter; Rothwell, John C; Lemon, Roger N; Frackowiak, Richard S

2005-07-01

Transcranial direct current stimulation (tDCS) of the primary motor hand area (M1) can produce lasting polarity-specific effects on corticospinal excitability and motor learning in humans. In 16 healthy volunteers, O positron emission tomography (PET) of regional cerebral blood flow (rCBF) at rest and during finger movements was used to map lasting changes in regional synaptic activity following 10 min of tDCS (+/-1 mA). Bipolar tDCS was given through electrodes placed over the left M1 and right frontopolar cortex. Eight subjects received anodal or cathodal tDCS of the left M1, respectively. When compared to sham tDCS, anodal and cathodal tDCS induced widespread increases and decreases in rCBF in cortical and subcortical areas. These changes in rCBF were of the same magnitude as task-related rCBF changes during finger movements and remained stable throughout the 50-min period of PET scanning. Relative increases in rCBF after real tDCS compared to sham tDCS were found in the left M1, right frontal pole, right primary sensorimotor cortex and posterior brain regions irrespective of polarity. With the exception of some posterior and ventral areas, anodal tDCS increased rCBF in many cortical and subcortical regions compared to cathodal tDCS. Only the left dorsal premotor cortex demonstrated an increase in movement related activity after cathodal tDCS, however, modest compared with the relatively strong movement-independent effects of tDCS. Otherwise, movement related activity was unaffected by tDCS. Our results indicate that tDCS is an effective means of provoking sustained and widespread changes in regional neuronal activity. The extensive spatial and temporal effects of tDCS need to be taken into account when tDCS is used to modify brain function.

Enhanced motor skill acquisition in the non-dominant upper extremity using intermittent theta burst stimulation and transcranial direct current stimulation.

Science.gov (United States)

Butts, Raymond J; Kolar, Melissa B; Newman-Norlund, Roger D

2014-01-01

Individuals suffering from motor impairments often require physical therapy (PT) to help improve their level of function. Previous investigations suggest that both intermittent theta burst stimulation (iTBS) and bihemispheric transcranial direct current stimulation (tDCS) may increase the speed and extent of motor learning/relearning. The purpose of the current study was to explore the feasibility and effectiveness of a novel, non-invasive brain stimulation approach that combined an iTBS primer, and bihemispheric stimulation coupled with motor training. We hypothesized that individuals exposed to this novel treatment would make greater functional improvements than individuals undergoing sham stimulation when tested immediately following, 24-h, and 7-days post-training. A total of 26 right-handed, healthy young adults were randomly assigned to either a treatment (n = 15) or control group (n = 12). iTBS (20 trains of 10 pulse triplets each delivered at 80% active motor threshold (AMT) / 50 Hz over 191.84 s) and bihemispheric tDCS (1.0 ma for 20 min) were used as a primer to, and in conjunction with, 20 min of motor training, respectively. Our primary outcome measure was performance on the Jebsen-Taylor Hand Function (JTHF) test. Participants tolerated the combined iTBS/bihemispheric stimulation treatment without complaint. While performance gains in the sham and stimulation group were not significant immediately after training, they were nearly significant 24-h post training (p = 0.055), and were significant at 7-days post training (p iTBS/bihemispheric stimulation protocol is both feasible and effective. Future research should examine the mechanistic explanation of this approach as well as the potential of using this approach in clinical populations.

Repetitive Transcranial Magnetic Stimulation: a Novel Approach for Treating Oropharyngeal Dysphagia

OpenAIRE

Michou, Emilia; Raginis-Zborowska, Alicja; Watanabe, Masahiro; Lodhi, Taha; Hamdy, Shaheen

2016-01-01

In recent years, repetitive transcranial magnetic stimulation, a technique used to produce human central neurostimulation, has attracted increased interest and been applied experimentally in the treatment of dysphagia. This review presents a synopsis of the current research for the application of repetitive transcranial magnetic stimulation (rTMS) on dysphagia. Here, we review the mechanisms underlying the effects of rTMS and the results from studies on both healthy volunteers and dysphagic p...

ELSI: A unified software interface for Kohn-Sham electronic structure solvers

Science.gov (United States)

Yu, Victor Wen-zhe; Corsetti, Fabiano; García, Alberto; Huhn, William P.; Jacquelin, Mathias; Jia, Weile; Lange, Björn; Lin, Lin; Lu, Jianfeng; Mi, Wenhui; Seifitokaldani, Ali; Vázquez-Mayagoitia, Álvaro; Yang, Chao; Yang, Haizhao; Blum, Volker

2018-01-01

Solving the electronic structure from a generalized or standard eigenproblem is often the bottleneck in large scale calculations based on Kohn-Sham density-functional theory. This problem must be addressed by essentially all current electronic structure codes, based on similar matrix expressions, and by high-performance computation. We here present a unified software interface, ELSI, to access different strategies that address the Kohn-Sham eigenvalue problem. Currently supported algorithms include the dense generalized eigensolver library ELPA, the orbital minimization method implemented in libOMM, and the pole expansion and selected inversion (PEXSI) approach with lower computational complexity for semilocal density functionals. The ELSI interface aims to simplify the implementation and optimal use of the different strategies, by offering (a) a unified software framework designed for the electronic structure solvers in Kohn-Sham density-functional theory; (b) reasonable default parameters for a chosen solver; (c) automatic conversion between input and internal working matrix formats, and in the future (d) recommendation of the optimal solver depending on the specific problem. Comparative benchmarks are shown for system sizes up to 11,520 atoms (172,800 basis functions) on distributed memory supercomputing architectures.

Time-dependent internal density functional theory formalism and Kohn-Sham scheme for self-bound systems

International Nuclear Information System (INIS)

Messud, Jeremie

2009-01-01

The stationary internal density functional theory (DFT) formalism and Kohn-Sham scheme are generalized to the time-dependent case. It is proven that, in the time-dependent case, the internal properties of a self-bound system (such as an atomic nuclei or a helium droplet) are all defined by the internal one-body density and the initial state. A time-dependent internal Kohn-Sham scheme is set up as a practical way to compute the internal density. The main difference from the traditional DFT formalism and Kohn-Sham scheme is the inclusion of the center-of-mass correlations in the functional.

Transcranial Doppler sonography in familial hemiplegic migraine

International Nuclear Information System (INIS)

Pierelli, F.; Pauri, F.; Cupini, L.M.; Fiermonte, G.; Rizzo, P.A.

1991-01-01

A patient affected by familial hemiplegic migraine underwent transcranial Doppler sonography twice: the first during a spontaneous attack with right hemiparesis and aphasia, the second during a headachefree period. During the attack the following haemodynamic changes were seen: (a) bilateral increase in the middle cerebral artery and anterior cerebral artery blood flow velocities (this increase was more pronounced on the left side), (b) decreased systo-diastolic ratio and pulsatility index on the right side, (c) increased systo-diastolic ratio and pulsatility index on the left side. The results indicate that during the attack in this familial hemiplegic migraine patient, a diffuse vasoconstriction of the basal cerebral arteries developed. Moreover, transcranial Doppler sonography data suggest that a prolonged vasoconstriction of the peripheral arterioles could play a role in determining the neurological symptoms in this syndrome. 13 refs., 1 figs., 1 tab

Transcranial Doppler sonography in familial hemiplegic migraine

Energy Technology Data Exchange (ETDEWEB)

Pierelli, F.; Pauri, F.; Cupini, L.M.; Fiermonte, G.; Rizzo, P.A. (Universita la Sapienza, Roma (Italy))

1991-02-01

A patient affected by familial hemiplegic migraine underwent transcranial Doppler sonography twice: the first during a spontaneous attack with right hemiparesis and aphasia, the second during a headachefree period. During the attack the following haemodynamic changes were seen: (a) bilateral increase in the middle cerebral artery and anterior cerebral artery blood flow velocities (this increase was more pronounced on the left side), (b) decreased systo-diastolic ratio and pulsatility index on the right side, (c) increased systo-diastolic ratio and pulsatility index on the left side. The results indicate that during the attack in this familial hemiplegic migraine patient, a diffuse vasoconstriction of the basal cerebral arteries developed. Moreover, transcranial Doppler sonography data suggest that a prolonged vasoconstriction of the peripheral arterioles could play a role in determining the neurological symptoms in this syndrome. 13 refs., 1 figs., 1 tab.

The ethics of sham surgery on research subjects with cognitive impairments that affect decision-making capacity.

Science.gov (United States)

Resnik, David B; Miller, Frank

2010-09-01

Populations recruited to participate in sham surgery clinical trials sometimes include patients with cognitive impairments that affect decision-making capacity. In this commentary we examine arguments for and against including these patients in sham surgery clinical trials. We argue that patients with cognitive impairments that affect decision-making capacity should not be excluded from a sham surgery clinical trial if there are scientific reasons for including them in the study and basic ethical requirements for clinical research are met. Published by Elsevier Inc.

Smart candle soot coated membranes for on-demand immiscible oil/water mixture and emulsion switchable separation.

Science.gov (United States)

Li, Jian; Zhao, Zhihong; Li, Dianming; Tian, Haifeng; Zha, Fei; Feng, Hua; Guo, Lin

2017-09-21

Oil/water separation is of great importance for the treatment of oily wastewater, including immiscible light/heavy oil-water mixtures, oil-in-water or water-in-oil emulsions. Smart surfaces with responsive wettability have received extensive attention especially for controllable oil/water separation. However, traditional smart membranes with a switchable wettability between superhydrophobicity and superhydrophilicity are limited to certain responsive materials and continuous external stimuli, such as pH, electrical field or light irradiation. Herein, a candle soot coated mesh (CSM) with a larger pore size and a candle soot coated PVDF membrane (CSP) with a smaller pore size with underwater superoleophobicity and underoil superhydrophobicity were successfully fabricated, which can be used for on-demand immiscible oil/water mixtures and surfactants-stabilized oil/water emulsion separation, respectively. Without any continuous external stimulus, the wettability of our membranes could be reversibly switched between underwater superoleophobicity and underoil superhydrophobicity simply by drying and washing alternately, thus achieving effective and switchable oil/water separation with excellent separation efficiency. We believe that such smart materials will be promising candidates for use in the removal of oil pollutants in the future.

Long-Term Effects of Repeated Prefrontal Cortex Transcranial Direct Current Stimulation (tDCS) on Food Craving in Normal and Overweight Young Adults.

Science.gov (United States)

Ljubisavljevic, M; Maxood, K; Bjekic, J; Oommen, J; Nagelkerke, N

The dorsolateral prefrontal cortex (DLPFC) plays an important role in the regulation of food intake. Several previous studies demonstrated that a single session of transcranial direct current stimulation (tDCS) of the DLPFC reduces food craving and caloric intake. We hypothesized that repeated tDCS of the right DLPFC cortex may exert long-term changes in food craving in young, healthy adults and that these changes may differ between normal and overweight subjects. Thirty healthy individuals who reported frequent food cravings without a prior history of eating disorders were initially recruited. Subjects were randomized into an ACTIVE group who received 5 days of real tDCS (20 minutes, anode right-cathode left montage, 2 mA with current density kept at 0.06 mA/cm2, 1 min ramp-up/ramp-down), and a SHAM group, who received one day of real tDCS, on the first day (same parameters), followed by 4 days of sham tDCS. Food craving intensity was examined by Food Craving Questionnaires State and Trait and Food Craving Inventory before, during, (5-days) and one month (30-days) after tDCS. Single session of tDCS significantly reduced the intensity of current food craving (FCQ-S). Five days of active tDCS significantly reduced habitual experiences of food craving (FCQ-T), when compared to baseline pre-stimulation levels. Furthermore, both current (FCQ-S) and habitual craving (FCQ-T) were significantly reduced 30 days after active tDCS, while sham tDCS, i.e. a single tDCS session did not have significant effects. Also, active tDCS significantly decreased craving for fast food and sweets, and to a lesser degree for fat, while it did not have significant effects on craving for carbohydrates (FCI). There were no significant differences between individual FCQ-T subscales (craving dimensions) after 5 or 30 days of either sham or active tDCS. Changes in craving were not significantly associated with the initial weight, or with weight changes 30 days after the stimulation in the

Probing phase- and frequency-dependent characteristics of cortical interneurons using combined transcranial alternating current stimulation and transcranial magnetic stimulation.

Science.gov (United States)

Hussain, Sara J; Thirugnanasambandam, Nivethida

2017-06-01

Paired-pulse transcranial magnetic stimulation (TMS) and peripheral stimulation combined with TMS can be used to study cortical interneuronal circuitry. By combining these procedures with concurrent transcranial alternating current stimulation (tACS), Guerra and colleagues recently showed that different cortical interneuronal populations are differentially modulated by the phase and frequency of tACS-imposed oscillations (Guerra A, Pogosyan A, Nowak M, Tan H, Ferreri F, Di Lazzaro V, Brown P. Cerebral Cortex 26: 3977-2990, 2016). This work suggests that different cortical interneuronal populations can be characterized by their phase and frequency dependency. Here we discuss how combining TMS and tACS can reveal the frequency at which cortical interneuronal populations oscillate, the neuronal origins of behaviorally relevant cortical oscillations, and how entraining cortical oscillations could potentially treat brain disorders. Copyright © 2017 the American Physiological Society.

A Planar Switchable 3-D-Coverage Phased Array Antenna and Its User Effects for 28-GHz Mobile Terminal Applications

DEFF Research Database (Denmark)

Zhang, Shuai; Chen, Xiaoming; Syrytsin, Igor A.

2017-01-01

This paper introduces a planar switchable 3D-coverage phased array for 28 GHz mobile terminal applications. In order to realize 3D-coverage beam scan with a simple planar array, chassis surface waves are efficiently excited and controlled by three identical slot subarrays. Three subarrays switch...

Transcranial magnetic stimulation for the treatment of major depression

Directory of Open Access Journals (Sweden)

Janicak PG

2015-06-01

Full Text Available Philip G Janicak, Mehmet E DokucuDepartment of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USAAbstract: Major depression is often difficult to diagnose accurately. Even when the diagnosis is properly made, standard treatment approaches (eg, psychotherapy, medications, or their combination are often inadequate to control acute symptoms or maintain initial benefit. Additional obstacles involve safety and tolerability problems, which frequently preclude an adequate course of treatment. This leaves an important gap in our ability to properly manage major depression in a substantial proportion of patients, leaving them vulnerable to ensuing complications (eg, employment-related disability, increased risk of suicide, comorbid medical disorders, and substance abuse. Thus, there is a need for more effective and better tolerated approaches. Transcranial magnetic stimulation is a neuromodulation technique increasingly used to partly fill this therapeutic void. In the context of treating depression, we critically review the development of transcranial magnetic stimulation, focusing on the results of controlled and pragmatic trials for depression, which consider its efficacy, safety, and tolerability.Keywords: electroconvulsive therapy, treatment-resistant depression, major depression, transcranial magnetic stimulation

Transcranial Magnetic Stimulation in Children

OpenAIRE

Garvey, Marjorie A.; Mall, Volker

2008-01-01

Developmental disabilities (e.g. attention deficit disorder; cerebral palsy) are frequently associated with deviations of the typical pattern of motor skill maturation. Neurophysiologic tools, such as transcranial magnetic stimulation (TMS), which probe motor cortex function, can potentially provide insights into both typical neuromotor maturation and the mechanisms underlying the motor skill deficits in children with developmental disabilities. These insights may set the stage for finding ef...

Transcranial direct current stimulation combined with aerobic exercise to optimize analgesic responses in fibromyalgia: A randomized placebo-controlled clinical trial

Directory of Open Access Journals (Sweden)

Mariana Emerenciano Mendonça

2016-03-01

Full Text Available Fibromyalgia is a chronic pain syndrome that is associated with maladaptive plasticity in neural central circuits. One of the neural circuits that are involved in pain in fibromyalgia is the primary motor cortex. We tested a combination intervention that aimed to modulate the motor system: transcranial direct current stimulation (tDCS of the primary motor cortex (M1 and aerobic exercise (AE. In this phase II, sham-controlled randomized clinical trial, 45 subjects were assigned to 1 of 3 groups: tDCS + AE, AE only, and tDCS only. The following outcomes were assessed: intensity of pain, level of anxiety, quality of life, mood, pressure pain threshold, and cortical plasticity, as indexed by transcranial magnetic stimulation. There was a significant effect for the group-time interaction for intensity of pain, demonstrating that tDCS/AE was superior to AE (F(13,364=2.25, p=0.007 and tDCS (F(13.364=2.33, p=0.0056 alone. Post hoc adjusted analysis showed a difference between tDCS/AE and tDCS group after the first week of stimulation and after one month intervention period (p=0.02 and p=0.03, respectively. Further, after treatment there was a significant difference between groups in anxiety and mood levels. The combination treatment effected the greatest response. The three groups had no differences regarding responses in motor cortex plasticity, as assessed by TMS. The combination of tDCS with aerobic exercise is superior compared with each individual intervention (cohen’s d effect sizes > 0.55. The combination intervention had a significant effect on pain, anxiety and mood. Based on the similar effects on cortical plasticity outcomes, the combination intervention might have affected other neural circuits, such as those that control the affective-emotional aspects of pain.

Sex Mediates the Effects of High-Definition Transcranial Direct Current Stimulation on "Mind-Reading".

Science.gov (United States)

Martin, A K; Huang, J; Hunold, A; Meinzer, M

2017-12-16

Sex differences in social cognitive ability are well established, including measures of Theory of Mind (ToM). The aim of this study was to investigate if sex mediates the effects of high-definition transcranial direct current stimulation (HD-tDCS) administered to a key hub of the social brain (i.e., the dorsomedial prefrontal cortex, dmPFC) on the Reading the Mind in the Eyes Test (RMET). Forty healthy young adults (18-35 years) were randomly allocated to receive either anodal or cathodal HD-tDCS in sham HD-tDCS controlled, double blind designs. In each of the two sessions, subjects completed the RMET. Anodal stimulation to the dmPFC increased accuracy on the RMET in females only. To assure regional specificity we performed a follow-up study stimulating the right temporoparietal junction and found no effect in either sex. The current study is the first to show improved performance on the RMET after tDCS to the dmPFC in females only. The polarity-specific effects and use of focal HD-tDCS provide evidence for sex-dependent differences in dmPFC function in relation to the RMET. Future studies using tDCS to study or improve ToM, need to consider sex. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Effects of short-term swimming exercise on bone mineral density, geometry, and microstructural properties in sham and ovariectomized rats

Directory of Open Access Journals (Sweden)

Foong Kiew Ooi

2014-12-01

Full Text Available Little information exists about the effects of swimming exercise on bone health in ovariectomized animals with estrogen deficiency, which resembles the postmenopausal state and age-related bone loss in humans. This study investigated the effects of swimming exercise on tibia and femur bone mineral density (BMD, geometry, and microstructure in sham and ovariectomized rats. Forty 3-month-old female rats were divided into four groups: sham operated-sedentary control (Sham-control, sham operated with swimming exercise group (Sham-Swim, ovariectomy-sedentary control (OVx-control, and ovariectomy and swimming exercise (OVx-Swim groups. Swimming sessions were performed by the rats 90 minutes/day for 5 days/week for a total of 8 weeks. At the end of the study, tibial and femoral proximal volumetric total BMD, midshaft cortical volumetric BMD, cross-sectional area, and cross-sectional moment of inertia (MOI, and bone microstructural properties were measured for comparison. Data were analyzed using one-way analysis of variance (ANOVA. The Sham-Swim group exhibited significantly (p < 0.05; one-way ANOVA greater values in bone geometry parameters, that is, tibial midshaft cortical area and MOI compared to the Sham-control group. However, no significant differences were observed in these parameters between the Ovx-Swim and Ovx-control groups. There were no significant differences in femoral BMD between the Sham-Swim and Sham-control groups. Nevertheless, the Ovx-Swim group elicited significantly (p < 0.05; one-way ANOVA higher femoral proximal total BMD and improved bone microstructure compared to the Ovx-Sham group. In conclusion, the positive effects of swimming on bone properties in the ovariectomized rats in the present study may suggest that swimming as a non- or low-weight-bearing exercise may be beneficial for enhancing bone health in the postmenopausal population.

Against Strong Ethical Parity: Situated Cognition Theses and Transcranial Brain Stimulation.

Science.gov (United States)

Heinrichs, Jan-Hendrik

2017-01-01

According to a prominent suggestion in the ethics of transcranial neurostimulation the effects of such devices can be treated as ethically on par with established, pre-neurotechnological alterations of the mind. This parity allegedly is supported by situated cognition theories showing how external devices can be part of a cognitive system. This article will evaluate this suggestion. It will reject the claim, that situated cognition theories support ethical parity. It will however point out another reason, why external carriers or modifications of the mental might come to be considered ethically on par with internal carriers. Section "Why Could There Be Ethical Parity between Neural Tissue and External Tools?" presents the ethical parity theses between external and internal carriers of the mind as well as neurotechnological alterations and established alterations. Section "Extended, Embodied, Embedded: Situated Cognition as a Relational Thesis" will elaborate the different situated cognition approaches and their relevance for ethics. It will evaluate, whether transcranial stimulation technologies are plausible candidates for situated cognition theses. Section "On the Ethical Relevance of Situated Cognition Theses" will discuss criteria for evaluating whether a cognitive tool is deeply embedded with a cognitive system and apply these criteria to transcranial brain stimulation technologies. Finally it will discuss the role diverse versions of situated cognition theory can play in the ethics of altering mental states, especially the ethics of transcranial brain stimulation technologies.

Transcranial electrical stimulation accelerates human sleep homeostasis.

Directory of Open Access Journals (Sweden)

Davide Reato

Full Text Available The sleeping brain exhibits characteristic slow-wave activity which decays over the course of the night. This decay is thought to result from homeostatic synaptic downscaling. Transcranial electrical stimulation can entrain slow-wave oscillations (SWO in the human electro-encephalogram (EEG. A computational model of the underlying mechanism predicts that firing rates are predominantly increased during stimulation. Assuming that synaptic homeostasis is driven by average firing rates, we expected an acceleration of synaptic downscaling during stimulation, which is compensated by a reduced drive after stimulation. We show that 25 minutes of transcranial electrical stimulation, as predicted, reduced the decay of SWO in the remainder of the night. Anatomically accurate simulations of the field intensities on human cortex precisely matched the effect size in different EEG electrodes. Together these results suggest a mechanistic link between electrical stimulation and accelerated synaptic homeostasis in human sleep.

Je pense donc je fais: transcranial direct current stimulation modulates brain oscillations associated with motor imagery and movement observation

Directory of Open Access Journals (Sweden)

Olivia Morgan Lapenta

2013-06-01

Full Text Available Motor system neural networks are activated during movement imagery, observation and execution, with a neural signature characterized by suppression of the Mu rhythm. In order to investigate the origin of this neurophysiological marker, we tested whether transcranial direct current stimulation (tDCS modifies Mu rhythm oscillations during tasks involving observation and imagery of biological and non-biological movements. We applied tDCS (anodal, cathodal and sham in 21 male participants (mean age 23.8+3.06, over the left M1 with a current of 2mA for 20 minutes. Following this, we recorded the EEG at C3, C4 and Cz and surrounding C3 and C4 electrodes. Analyses of C3 and C4 showed significant effects for biological vs. non-biological movement (p=0.005, and differential hemisphere effects according to the type of stimulation (p=0.04 and type of movement (p=0.02. Analyses of surrounding electrodes revealed significant interaction effects considering type of stimulation and imagery or observation of biological or non-biological movement (p=0.03. The main findings of this study were (i Mu desynchronization during biological movement of the hand region in the contralateral hemisphere after sham tDCS; (ii polarity-dependent modulation effects of tDCS on the Mu rhythm, i.e. anodal tDCS led to Mu synchronization while cathodal tDCS led to Mu desynchronization during movement observation and imagery (iii specific focal and opposite inter-hemispheric effects, i.e. contrary effects for the surrounding electrodes during imagery condition and also for inter-hemispheric electrodes (C3 vs. C4. These findings provide insights into the cortical oscillations during movement observation and imagery. Furthermore it shows that tDCS can be highly focal when guided by a behavioral task.

Primed low-frequency repetitive transcranial magnetic stimulation and constraint-induced movement therapy in pediatric hemiparesis: a randomized controlled trial.

Science.gov (United States)

Gillick, Bernadette T; Krach, Linda E; Feyma, Tim; Rich, Tonya L; Moberg, Kelli; Thomas, William; Cassidy, Jessica M; Menk, Jeremiah; Carey, James R

2014-01-01

The aim of this study was to determine the feasibility and efficacy of five treatments of 6 Hz primed, low-frequency, repetitive transcranial magnetic stimulation (rTMS) combined with constraint-induced movement therapy (CIMT) to promote recovery of the paretic hand in children with congenital hemiparesis. Nineteen children with congenital hemiparesis aged between 8 and 17 years (10 males, nine females; mean age 10 years 10 months, SD 2 years 10 months; Manual Ability Classification Scale levels I-III) underwent five sessions of either real rTMS (n=10) or sham rTMS (n=9) alternated daily with CIMT. CIMT consisted of 13 days of continuous long-arm casting with five skin-check sessions. Each child received a total of 10 hours of one-to-one therapy. The primary outcome measure was the Assisting Hand Assessment (AHA) and the secondary outcome variables were the Canadian Occupational Performance Measure (COPM) and stereognosis. A Wilcoxon signed-rank sum test was used to analyze differences between pre- and post-test scores within the groups. Analysis of covariance was used to compute mean differences between groups adjusting for baseline. Fisher's exact test was used to compare individual change in AHA raw scores with the smallest detectable difference (SDD) of 4 points. All participants receiving treatment finished the study. Improvement in AHA differed significantly between groups (p=0.007). No significant differences in the secondary outcome measures were found. Eight out of 10 participants in the rTMS/CIMT group showed improvement greater than the SDD, but only two out of nine in the sham rTMS/CIMT group showed such improvement (p=0.023). No serious adverse events occurred. Primed, low-frequency rTMS combined with CIMT appears to be safe, feasible, and efficacious in pediatric hemiparesis. Larger clinical trials are now indicated. © 2013 Mac Keith Press.

Je pense donc je fais: transcranial direct current stimulation modulates brain oscillations associated with motor imagery and movement observation.

Science.gov (United States)

Lapenta, Olivia M; Minati, Ludovico; Fregni, Felipe; Boggio, Paulo S

2013-01-01

Motor system neural networks are activated during movement imagery, observation and execution, with a neural signature characterized by suppression of the Mu rhythm. In order to investigate the origin of this neurophysiological marker, we tested whether transcranial direct current stimulation (tDCS) modifies Mu rhythm oscillations during tasks involving observation and imagery of biological and non-biological movements. We applied tDCS (anodal, cathodal, and sham) in 21 male participants (mean age 23.8 ± 3.06), over the left M1 with a current of 2 mA for 20 min. Following this, we recorded the EEG at C3, C4, and Cz and surrounding C3 and C4 electrodes. Analyses of C3 and C4 showed significant effects for biological vs. non-biological movement (p = 0.005), and differential hemisphere effects according to the type of stimulation (p = 0.04) and type of movement (p = 0.02). Analyses of surrounding electrodes revealed significant interaction effects considering type of stimulation and imagery or observation of biological or non-biological movement (p = 0.03). The main findings of this study were (1) Mu desynchronization during biological movement of the hand region in the contralateral hemisphere after sham tDCS; (2) polarity-dependent modulation effects of tDCS on the Mu rhythm, i.e., anodal tDCS led to Mu synchronization while cathodal tDCS led to Mu desynchronization during movement observation and imagery (3) specific focal and opposite inter-hemispheric effects, i.e., contrary effects for the surrounding electrodes during imagery condition and also for inter-hemispheric electrodes (C3 vs. C4). These findings provide insights into the cortical oscillations during movement observation and imagery. Furthermore, it shows that tDCS can be highly focal when guided by a behavioral task.

Combining transcranial direct current stimulation and tailor-made notched music training to decrease tinnitus-related distress--a pilot study.

Directory of Open Access Journals (Sweden)

Henning Teismann

Full Text Available The central auditory system has a crucial role in tinnitus generation and maintenance. Curative treatments for tinnitus do not yet exist. However, recent attempts in the therapeutic application of both acoustic stimulation/training procedures and electric/magnetic brain stimulation techniques have yielded promising results. Here, for the first time we combined tailor-made notched music training (TMNMT with transcranial direct current stimulation (tDCS in an effort to modulate TMNMT efficacy in the treatment of 32 patients with tonal tinnitus and without severe hearing loss. TMNMT is characterized by regular listening to so-called notched music, which is generated by digitally removing the frequency band of one octave width centered at the individual tinnitus frequency. TMNMT was applied for 10 subsequent days (2.5 hours of daily treatment. During the initial 5 days of treatment and the initial 30 minutes of TMNMT sessions, tDCS (current strength: 2 mA; anodal (N = 10 vs. cathodal (N = 11 vs. sham (N = 11 groups was applied simultaneously. The active electrode was placed on the head surface over left auditory cortex; the reference electrode was put over right supra-orbital cortex. To evaluate treatment outcome, tinnitus-related distress and perceived tinnitus loudness were assessed using standardized tinnitus questionnaires and a visual analogue scale. The results showed a significant treatment effect reflected in the Tinnitus Handicap Questionnaire that was largest after 5 days of treatment. This effect remained significant at the end of follow-up 31 days after treatment cessation. Crucially, tDCS did not significantly modulate treatment efficacy--it did not make a difference whether anodal, cathodal, or sham tDCS was applied. Possible explanations for the findings and functional modifications of the experimental design for future studies (e.g. the selection of control conditions are discussed.

Different effects of scopolamine on learning, memory, and nitric oxide metabolite levels in hippocampal tissues of ovariectomized and Sham-operated rats

Directory of Open Access Journals (Sweden)

Hamid Azizi-Malekabadi

2012-06-01

Full Text Available Different effects of scopolamine on learning, memory, and nitric oxide (NO metabolites in hippocampal tissues of ovariectomized (OVX and sham-operated rats were investigated. The animals in the Sham-Scopolamine (Sham-Sco and OVX-Scopolamine (OVX-Sco Groups were treated with 2 mg/kg scopolamine before undergoing the Morris water maze, while the animals in the Sham and OVX Groups received saline. The time latency and path length were significantly higher in both the Sham-Sco and the OVX-Sco Groups, in comparison with the Sham and OVX Groups, respectively (p<0.001. Significantly lower NO metabolite levels in the hippocampi of the Sham-Sco Group were observed, compared with the Sham Group (p<0.001, while there was no significant difference between the OVX-Sco and OVX Groups. The decreased NO level in the hippocampus may play a role in the learning and memory deficits induced by scopolamine. However, it seems that the effect of scopolamine on hippocampal NO differs between situations of presence and absence of ovarian hormones.

Simultaneous transcranial direct current stimulation (tDCS) and whole-head magnetoencephalography (MEG): assessing the impact of tDCS on slow cortical magnetic fields.

Science.gov (United States)

Garcia-Cossio, Eliana; Witkowski, Matthias; Robinson, Stephen E; Cohen, Leonardo G; Birbaumer, Niels; Soekadar, Surjo R

2016-10-15

Transcranial direct current stimulation (tDCS) can influence cognitive, affective or motor brain functions. Whereas previous imaging studies demonstrated widespread tDCS effects on brain metabolism, direct impact of tDCS on electric or magnetic source activity in task-related brain areas could not be confirmed due to the difficulty to record such activity simultaneously during tDCS. The aim of this proof-of-principal study was to demonstrate the feasibility of whole-head source localization and reconstruction of neuromagnetic brain activity during tDCS and to confirm the direct effect of tDCS on ongoing neuromagnetic activity in task-related brain areas. Here we show for the first time that tDCS has an immediate impact on slow cortical magnetic fields (SCF, 0-4Hz) of task-related areas that are identical with brain regions previously described in metabolic neuroimaging studies. 14 healthy volunteers performed a choice reaction time (RT) task while whole-head magnetoencephalography (MEG) was recorded. Task-related source-activity of SCFs was calculated using synthetic aperture magnetometry (SAM) in absence of stimulation and while anodal, cathodal or sham tDCS was delivered over the right primary motor cortex (M1). Source reconstruction revealed task-related SCF modulations in brain regions that precisely matched prior metabolic neuroimaging studies. Anodal and cathodal tDCS had a polarity-dependent impact on RT and SCF in primary sensorimotor and medial centro-parietal cortices. Combining tDCS and whole-head MEG is a powerful approach to investigate the direct effects of transcranial electric currents on ongoing neuromagnetic source activity, brain function and behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

Transcranial extracellular impedance control (tEIC modulates behavioral performances.

Directory of Open Access Journals (Sweden)

Ayumu Matani

Full Text Available Electric brain stimulations such as transcranial direct current stimulation (tDCS, transcranial random noise stimulation (tRNS, and transcranial alternating current stimulation (tACS electrophysiologically modulate brain activity and as a result sometimes modulate behavioral performances. These stimulations can be viewed from an engineering standpoint as involving an artificial electric source (DC, noise, or AC attached to an impedance branch of a distributed parameter circuit. The distributed parameter circuit is an approximation of the brain and includes electric sources (neurons and impedances (volume conductors. Such a brain model is linear, as is often the case with the electroencephalogram (EEG forward model. Thus, the above-mentioned current stimulations change the current distribution in the brain depending on the locations of the electric sources in the brain. Now, if the attached artificial electric source were to be replaced with a resistor, or even a negative resistor, the resistor would also change the current distribution in the brain. In light of the superposition theorem, which holds for any linear electric circuit, attaching an electric source is different from attaching a resistor; the resistor affects each active electric source in the brain so as to increase (or decrease in some cases of a negative resistor the current flowing out from each source. From an electrophysiological standpoint, the attached resistor can only control the extracellular impedance and never causes forced stimulation; we call this technique transcranial extracellular impedance control (tEIC. We conducted a behavioral experiment to evaluate tEIC and found evidence that it had real-time enhancement and depression effects on EEGs and a real-time facilitation effect on reaction times. Thus, tEIC could be another technique to modulate behavioral performance.

Temperature-Controlled Delivery of Radiofrequency Energy in Fecal Incontinence: A Randomized Sham-Controlled Clinical Trial.

Science.gov (United States)

Visscher, Arjan P; Lam, Tze J; Meurs-Szojda, Maria M; Felt-Bersma, Richelle J F

2017-08-01

Controlled delivery of radiofrequency energy has been suggested as treatment for fecal incontinence. The aim of this study was to determine whether the clinical response to the radiofrequency energy procedure is superior to sham in patients with fecal incontinence. This was a randomized sham-controlled clinical trial from 2008 to 2015. This study was conducted in an outpatient clinic. Forty patients with fecal incontinence in whom maximal conservative management had failed were randomly assigned to receiving either radiofrequency energy or sham procedure. Fecal incontinence was measured using the Vaizey incontinence score (range, 0-24). The impact of fecal incontinence on quality of life was measured by using the fecal incontinence quality-of-life score (range, 1-4). Measurements were performed at baseline and at 6 months. Anorectal function was evaluated using anal manometry and anorectal endosonography at baseline and at 3 months. At baseline, Vaizey incontinence score was 16.8 (SD 2.9). At t = 6 months, the radiofrequency energy group improved by 2.5 points on the Vaizey incontinence score compared with the sham group (13.2 (SD 3.1), 15.6 (SD 3.3), p = 0.02). The fecal incontinence quality-of-life score at t = 6 months was not statistically different. Anorectal function did not show any alteration. Patients with severe fecal incontinence were included in the study, thus making it difficult to generalize the results. Both radiofrequency energy and sham procedure improved the fecal incontinence score, the radiofrequency energy procedure more than sham. Although statistically significant, the clinical impact for most of the patients was negligible. Therefore, the radiofrequency energy procedure should not be recommended for patients with fecal incontinence until patient-related factors associated with treatment success are known. See Video Abstract at http://links.lww.com/DCR/A373.

Efficient and reliable characterization of the corticospinal system using transcranial magnetic stimulation.

Science.gov (United States)

Kukke, Sahana N; Paine, Rainer W; Chao, Chi-Chao; de Campos, Ana C; Hallett, Mark

2014-06-01

The purpose of this study is to develop a method to reliably characterize multiple features of the corticospinal system in a more efficient manner than typically done in transcranial magnetic stimulation studies. Forty transcranial magnetic stimulation pulses of varying intensity were given over the first dorsal interosseous motor hot spot in 10 healthy adults. The first dorsal interosseous motor-evoked potential size was recorded during rest and activation to create recruitment curves. The Boltzmann sigmoidal function was fit to the data, and parameters relating to maximal motor-evoked potential size, curve slope, and stimulus intensity leading to half-maximal motor-evoked potential size were computed from the curve fit. Good to excellent test-retest reliability was found for all corticospinal parameters at rest and during activation with 40 transcranial magnetic stimulation pulses. Through the use of curve fitting, important features of the corticospinal system can be determined with fewer stimuli than typically used for the same information. Determining the recruitment curve provides a basis to understand the state of the corticospinal system and select subject-specific parameters for transcranial magnetic stimulation testing quickly and without unnecessary exposure to magnetic stimulation. This method can be useful in individuals who have difficulty in maintaining stillness, including children and patients with motor disorders.

Individual differences in learning correlate with modulation of brain activity induced by transcranial direct current stimulation

Science.gov (United States)

Falcone, Brian; Wada, Atsushi; Parasuraman, Raja

2018-01-01

Transcranial direct current stimulation (tDCS) has been shown to enhance cognitive performance on a variety of tasks. It is hypothesized that tDCS enhances performance by affecting task related cortical excitability changes in networks underlying or connected to the site of stimulation facilitating long term potentiation. However, many recent studies have called into question the reliability and efficacy of tDCS to induce modulatory changes in brain activity. In this study, our goal is to investigate the individual differences in tDCS induced modulatory effects on brain activity related to the degree of enhancement in performance, providing insight into this lack of reliability. In accomplishing this goal, we used functional magnetic resonance imaging (fMRI) concurrently with tDCS stimulation (1 mA, 30 minutes duration) using a visual search task simulating real world conditions. The experiment consisted of three fMRI sessions: pre-training (no performance feedback), training (performance feedback which included response accuracy and target location and either real tDCS or sham stimulation given), and post-training (no performance feedback). The right posterior parietal cortex was selected as the site of anodal tDCS based on its known role in visual search and spatial attention processing. Our results identified a region in the right precentral gyrus, known to be involved with visual spatial attention and orienting, that showed tDCS induced task related changes in cortical excitability that were associated with individual differences in improved performance. This same region showed greater activity during the training session for target feedback of incorrect (target-error feedback) over correct trials for the tDCS stim over sham group indicating greater attention to target features during training feedback when trials were incorrect. These results give important insight into the nature of neural excitability induced by tDCS as it relates to variability in

Transcranial Magnetic Stimulation of Medial Prefrontal and Cingulate Cortices Reduces Cocaine Self-Administration: A Pilot Study

Directory of Open Access Journals (Sweden)

Diana Martinez

2018-03-01

Full Text Available BackgroundPrevious studies have shown that repetitive transcranial magnetic stimulation (rTMS to the dorsolateral prefrontal cortex may serve as a potential treatment for cocaine use disorder (CUD, which remains a public health problem that is refractory to treatment. The goal of this pilot study was to investigate the effect of rTMS on cocaine self-administration in the laboratory. In the self-administration sessions, CUD participants chose between cocaine and an alternative reinforcer (money in order to directly measure cocaine-seeking behavior. The rTMS was delivered with the H7 coil, which provides stimulation to the medial prefrontal cortex (mPFC and anterior cingulate cortex (ACC. These brain regions were targeted based on previous imaging studies demonstrating alterations in their activation and connectivity in CUD.MethodsVolunteers with CUD were admitted to an inpatient unit for the entire study and assigned to one of three rTMS groups: high frequency (10 Hz, low frequency (1 Hz, and sham. Six participants were included in each group and the rTMS was delivered on weekdays for 3 weeks. The cocaine self-administration sessions were performed at three time points: at baseline (pre-TMS, session 1, after 4 days of rTMS (session 2, and after 13 days of rTMS (session 3. During each self-administration session, the outcome measure was the number of choices for cocaine.ResultsThe results showed a significant group by time effect (p = 0.02, where the choices for cocaine decreased between sessions 2 and 3 in the high frequency group. There was no effect of rTMS on cocaine self-administration in the low frequency or sham groups.ConclusionTaken in the context of the existing literature, these results contribute to the data showing that high frequency rTMS to the prefrontal cortex may serve as a potential treatment for CUD.

Transcranial Ultrasound in the Diagnosis of Parkinson’s Disease

Directory of Open Access Journals (Sweden)

Aniley Martínez González

2014-10-01

Full Text Available Parkinson’s disease is the second most common neurodegenerative disorder and, since it is associated with aging, the probability of developing this disease increases with age. The diagnosis of idiopathic Parkinson’s disease is based on clinical criteria; however, its differentiation from other forms of Parkinsonism can be difficult, especially in early stages of the disease. Transcranial ultrasound has become a tool for the diagnosis of this disorder, being very useful for its early diagnosis. Ultrasonographic findings characteristic of this disease include increased echogenicity of the substantia nigra in the midbrain measured through the temporal bone window. This paper discusses the usefulness of transcranial ultrasound for early diagnosis of patients with Parkinson's disease.

Electrical stimulation of the motor cortex enhances treatment outcome in post-stroke aphasia.

Science.gov (United States)

Meinzer, Marcus; Darkow, Robert; Lindenberg, Robert; Flöel, Agnes

2016-04-01

Transcranial direct current stimulation has shown promise to improve recovery in patients with post-stroke aphasia, but previous studies have only assessed stimulation effects on impairment parameters, and evidence for long-term maintenance of transcranial direct current stimulation effects from randomized, controlled trials is lacking. Moreover, due to the variability of lesions and functional language network reorganization after stroke, recent studies have used advanced functional imaging or current modelling to determine optimal stimulation sites in individual patients. However, such approaches are expensive, time consuming and may not be feasible outside of specialized research centres, which complicates incorporation of transcranial direct current stimulation in day-to-day clinical practice. Stimulation of an ancillary system that is functionally connected to the residual language network, namely the primary motor system, would be more easily applicable, but effectiveness of such an approach has not been explored systematically. We conducted a randomized, parallel group, sham-controlled, double-blind clinical trial and 26 patients with chronic aphasia received a highly intensive naming therapy over 2 weeks (8 days, 2 × 1.5 h/day). Concurrently, anodal-transcranial direct current stimulation was administered to the left primary motor cortex twice daily at the beginning of each training session. Naming ability for trained items (n = 60 pictures that could not be named during repeated baseline assessments), transfer to untrained items (n = 284 pictures) and generalization to everyday communication were assessed immediately post-intervention and 6 months later. Naming ability for trained items was significantly improved immediately after the end of the intervention in both the anodal (Cohen's d = 3.67) and sham-transcranial direct current stimulation groups (d = 2.10), with a trend for larger gains in the anodal-transcranial direct current stimulation group (d

Efficacy of Transcranial Magnetic Stimulation (TMS) in the Treatment of Schizophrenia: A Review of the Literature to Date.

Science.gov (United States)

Cole, Jonathan C; Green Bernacki, Carolyn; Helmer, Amanda; Pinninti, Narsimha; O'reardon, John P

2015-01-01

We reviewed the literature on transcranial magnetic stimulation and its uses and efficacy in schizophrenia. Multiple sources were examined on transcranial magnetic stimulation efficacy in relieving positive and negative symptoms of schizophrenia. Literature review was conducted via Ovid Medline and PubMed databases. We found multiple published studies and metaanalyses that give evidence that repetitive transcranial magnetic stimulation can have benefit in relieving positive and negative symptoms of schizophrenia, particularly auditory hallucinations. These findings should encourage the psychiatric community to expand research into other applications for which transcranial magnetic stimulation may be used to treat patients with psychiatric disability.

Chromogenic switchable glazing: Towards the development of the smart window

Energy Technology Data Exchange (ETDEWEB)

Lampert, C.M.

1995-06-01

The science and technology of chromogenic materials for switchable glazings in building applications is discussed. These glazings can be used for dynamic control of solar and visible energy. Currently many researchers and engineers are involved with the development of products in this field. A summary of activities in Japan, Europe, Australia, USA and Canada is made. The activities of the International Energy Agency are included. Both non-electrically activated and electrically activated glazings are discussed. Technologies covered in the first category are photochromics, and thermochromics and thermotropics. A discussion of electrically activated chromogenic glazings includes dispersed liquid crystals, dispersed particles and electrochromics. A selection of device structures and performance characteristics are compared. A discussion of transparent conductors is presented. Technical issues concerning large-area development of smart windows are discussed.

Transcranial Doppler velocimetry in aneurysmal subarachnoid haemorrhage

DEFF Research Database (Denmark)

Staalsø, J M; Edsen, T; Romner, B

2013-01-01

-coded transcranial Doppler (TCCD), with the secondary aim of describing prediction of angiographic vasospasm and mortality. METHODS: /st>Sixty patients and 70 healthy controls were each examined in duplicate by alternating operators. A total of 939 measurements divided on 201 examination sets were conducted by four...

[Effects of intermittent hypoxia on the responses of genioglossus motor cortex to transcranial magnetic stimulation in rats].

Science.gov (United States)

Li, Ting; Wang, Wei; Kong, De-lei; Su, Jiao; Kang, Jian

2012-04-01

To explore the influence of intermittent hypoxia on the responses of genioglossus motor cortex to transcranial magnetic stimulation. Male Sprague-Dawley rats were randomly divided into a control group and a chronic intermittent hypoxia group. Transcranial magnetic stimulation was applied in genioglossus motor cortex of the 2 groups. The responses of transcranial magnetic stimulation were recorded and analyzed by single factor analysis of variance. The anterolateral area provided an optimal motor evoked potential response to transcranial magnetic stimulation in the genioglossus motor cortex of the rats. Genioglossus motor evoked potential latency and amplitude were significantly modified by intermittent hypoxic exposure, with a significant decrease in latency (F = 3.294, P motor cortex in rats.

Utilizing stretch-tunable thermochromic elastomeric opal films as novel reversible switchable photonic materials.

Science.gov (United States)

Schäfer, Christian G; Lederle, Christina; Zentel, Kristina; Stühn, Bernd; Gallei, Markus

2014-11-01

In this work, the preparation of highly thermoresponsive and fully reversible stretch-tunable elastomeric opal films featuring switchable structural colors is reported. Novel particle architectures based on poly(diethylene glycol methylether methacrylate-co-ethyl acrylate) (PDEGMEMA-co-PEA) as shell polymer are synthesized via seeded and stepwise emulsion polymerization protocols. The use of DEGMEMA as comonomer and herein established synthetic strategies leads to monodisperse soft shell particles, which can be directly processed to opal films by using the feasible melt-shear organization technique. Subsequent UV crosslinking strategies open access to mechanically stable and homogeneous elastomeric opal films. The structural colors of the opal films feature mechano- and thermoresponsiveness, which is found to be fully reversible. Optical characterization shows that the combination of both stimuli provokes a photonic bandgap shift of more than 50 nm from 560 nm in the stretched state to 611 nm in the fully swollen state. In addition, versatile colorful patterns onto the colloidal crystal structure are produced by spatial UV-induced crosslinking by using a photomask. This facile approach enables the generation of spatially cross-linked switchable opal films with fascinating optical properties. Herein described strategies for the preparation of PDEGMEMA-containing colloidal architectures, application of the melt-shear ordering technique, and patterned crosslinking of the final opal films open access to novel stimuli-responsive colloidal crystal films, which are expected to be promising materials in the field of security and sensing applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Glassy carbon electrode modified with gold nanoparticles and hemoglobin in a chitosan matrix for improved pH-switchable sensing of hydrogen peroxide

International Nuclear Information System (INIS)

Liu, Yang; Shi, Liang; Gong, Jin; Fang, Yu-Ting; Bao, Ning; Gu, Hai-Ying; Zeng, Jiang

2015-01-01

Hemoglobin (Hb) has been demonstrated to endow electrochemical sensors with pH-switchable response because of the presence of carboxyl and amino groups. Hb was deposited in a chitosan matrix on a glassy carbon electrode (GCE) that was previously coated with clustered gold nanoparticles (Au-NPs) by electrodeposition. The switching behavior is active (“on”) to the negatively charged probe [Fe(CN) 6 3− ] at pH 4.0, but inactive (“off”) to the probe at pH 8.0. This switch is fully reversible by simply changing the pH value of the solution and can be applied for pH-controlled reversible electrochemical reduction of H 2 O 2 catalyzed by Hb. The modified electrode was tested for its response to the different electroactive probes. The response to these species strongly depends on pH which was cycled between 4 and 8. The effect is also attributed to the presence of pH dependent charges on the surface of the electrode which resulted in either electrostatic attraction or repulsion of the electroactive probes. The presence of Hb, in turn, enhances the pH-controllable response, and the electrodeposited Au-NPs improve the capability of switching. This study reveals the potential of protein based pH-switchable materials and also provides a simple and effective strategy for fabrication of switchable chemical sensors as exemplified in a pH-controllable electrode for hydrogen peroxide. (author)

Low-frequency transcranial magnetic stimulation is beneficial for enhancing synaptic plasticity in the aging brain.

Science.gov (United States)

Zhang, Zhan-Chi; Luan, Feng; Xie, Chun-Yan; Geng, Dan-Dan; Wang, Yan-Yong; Ma, Jun

2015-06-01

In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz) ameliorates synaptic plasticity and spatial cognitive deficits in learning-impaired mice. However, the mechanisms by which this treatment improves these deficits during normal aging are still unknown. Therefore, the current study investigated the effects of transcranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, synaptophysin and growth-associated protein 43 (both synaptic markers), to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcranial magnetic stimulation with low intensity (110% average resting motor threshold intensity, 1 Hz) increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippocampus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this regulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

Semantic Feature Training in Combination with Transcranial Direct Current Stimulation (tDCS for Progressive Anomia

Directory of Open Access Journals (Sweden)

Jinyi Hung

2017-05-01

Full Text Available We examined the effectiveness of a 2-week regimen of a semantic feature training in combination with transcranial direct current stimulation (tDCS for progressive naming impairment associated with primary progressive aphasia (N = 4 or early onset Alzheimer’s Disease (N = 1. Patients received a 2-week regimen (10 sessions of anodal tDCS delivered over the left temporoparietal cortex while completing a language therapy that consisted of repeated naming and semantic feature generation. Therapy targets consisted of familiar people, household items, clothes, foods, places, hygiene implements, and activities. Untrained items from each semantic category provided item level controls. We analyzed naming accuracies at multiple timepoints (i.e., pre-, post-, 6-month follow-up via a mixed effects logistic regression and individual differences in treatment responsiveness using a series of non-parametric McNemar tests. Patients showed advantages for naming trained over untrained items. These gains were evident immediately post tDCS. Trained items also showed a shallower rate of decline over 6-months relative to untrained items that showed continued progressive decline. Patients tolerated stimulation well, and sustained improvements in naming accuracy suggest that the current intervention approach is viable. Future implementation of a sham control condition will be crucial toward ascertaining whether neurostimulation and behavioral treatment act synergistically or alternatively whether treatment gains are exclusively attributable to either tDCS or the behavioral intervention.

Anodal Transcranial Direct Current Stimulation Provokes Neuroplasticity in Repetitive Mild Traumatic Brain Injury in Rats

Directory of Open Access Journals (Sweden)

Ho Jeong Kim

2017-01-01

Full Text Available Repetitive mild traumatic brain injury (rmTBI provokes behavioral and cognitive changes. But the study about electrophysiologic findings and managements of rmTBI is limited. In this study, we investigate the effects of anodal transcranial direct current stimulation (tDCS on rmTBI. Thirty-one Sprague Dawley rats were divided into the following groups: sham, rmTBI, and rmTBI treated by tDCS. Animals received closed head mTBI three consecutive times a day. Anodal tDCS was applied to the left motor cortex. We evaluated the motor-evoked potential (MEP and the somatosensory-evoked potential (SEP. T2-weighted magnetic resonance imaging was performed 12 days after rmTBI. After rmTBI, the latency of MEP was prolonged and the amplitude in the right hind limb was reduced in the rmTBI group. The latency of SEP was delayed and the amplitude was decreased after rmTBI in the rmTBI group. In the tDCS group, the amplitude in both hind limbs was increased after tDCS in comparison with the values before rmTBI. Anodal tDCS after rmTBI seems to be a useful tool for promoting transient motor recovery through increasing the synchronicity of cortical firing, and it induces early recovery of consciousness. It can contribute to management of concussion in humans if further study is performed.

Influence of transcranial direct current stimulation of the dorsolateral prefrontal cortex on pain related emotions: a study using electroencephalographic power spectrum analysis.

Science.gov (United States)

Maeoka, Hiroshi; Matsuo, Atsushi; Hiyamizu, Makoto; Morioka, Shu; Ando, Hiroshi

2012-03-14

Pain is a multidimensional experience with sensory-discriminative, cognitive-evaluative and affective-motivational components. Emotional factors such as unpleasantness or anxiety are known to have influence on pain in humans. The aim of this single-blinded, cross over study was to evaluate the effects of transcranial direct current stimulation (tDCS) on emotional aspects of pain in pain alleviation. Fifteen subjects (5 females, 10 males) volunteered to participate in this study. In an oddball paradigm, three categories of 20 pictures (unpleasant, neutral, and pleasant) served as rare target pictures from the International Affective Picture System (IAPS). The power of the delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-25 Hz), and gamma (30-40 Hz) frequency bands in the three categories were measured using electroencephalography during an oddball paradigm at pre- and post-anodal or sham tDCS above the left dorsolateral prefrontal cortex (DLPFC). Results showed that the beta band power was significantly increased, and the alpha band power was significantly decreased during unpleasant pictures after anodal tDCS compared with sham tDCS. Furthermore, regarding unpleasant pictures, subjective reports of Self Assessment Manikin (SAM) for emotional valence after anodal tDCS showed a significant decrease of unpleasantness. Therefore, emotional aspects of pain may be effectively alleviated by tDCS of the left DLPFC as was shown not only by subjective evaluation, but also by objective observation of cerebral neural activity. This processing may be mediated by facilitation of the descending pain inhibitory system through enhancing neural activity of the left DLPFC. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Functional interaction between right parietal and bilateral frontal cortices during visual search tasks revealed using functional magnetic imaging and transcranial direct current stimulation.

Directory of Open Access Journals (Sweden)

Amanda Ellison

Full Text Available The existence of a network of brain regions which are activated when one undertakes a difficult visual search task is well established. Two primary nodes on this network are right posterior parietal cortex (rPPC and right frontal eye fields. Both have been shown to be involved in the orientation of attention, but the contingency that the activity of one of these areas has on the other is less clear. We sought to investigate this question by using transcranial direct current stimulation (tDCS to selectively decrease activity in rPPC and then asking participants to perform a visual search task whilst undergoing functional magnetic resonance imaging. Comparison with a condition in which sham tDCS was applied revealed that cathodal tDCS over rPPC causes a selective bilateral decrease in frontal activity when performing a visual search task. This result demonstrates for the first time that premotor regions within the frontal lobe and rPPC are not only necessary to carry out a visual search task, but that they work together to bring about normal function.

Sham-controlled, randomized, feasibility trial of acupuncture for prevention of radiation-induced xerostomia among patients with nasopharyngeal carcinoma

Science.gov (United States)

Meng, Zhiqiang; Garcia, M. Kay; Hu, Chaosu; Chiang, Joseph; Chambers, Mark; Rosenthal, David I.; Peng, Huiting; Wu, Caijun; Zhao, Qi; Zhao, Genming; Liu, Luming; Spelman, Amy; Palmer, J. Lynn; Wei, Qi; Cohen, Lorenzo

2013-01-01

Background Xerostomia (dry mouth) after head/neck radiation is a common problem among cancer patients. Quality of life (QOL) is impaired, and available treatments are of little benefit. This trial determined the feasibility of conducting a sham-controlled trial of acupuncture and whether acupuncture could prevent xerostomia among head/neck patients undergoing radiotherapy. Methods A sham controlled, feasibility trial was conducted at Fudan University Shanghai Cancer Center, Shanghai, China among patients with nasopharyngeal carcinoma undergoing radiotherapy. To determine feasibility of a sham procedure, 23 patients were randomized to real acupuncture (N = 11) or to sham acupuncture (N = 12). Patients were treated 3 times/week during their course of radiotherapy. Subjective measures were the Xerostomia Questionnaire (XQ) and MD Anderson Symptom Inventory for Head and Neck Cancer (MDASI-HN). Objective measures were unstimulated whole salivary flow rates (UWSFR) and stimulated salivary flow rates (SSFR). Patients were followed for 1 month after radiotherapy. Results XQ scores for acupuncture were significantly lower than sham controls starting in week 3 and lasted through the 1-month follow-up (all P’s xerostomia symptoms and improved QOL when compared with sham acupuncture. Large-scale, multi-center, randomized, placebo-controlled trials are now needed. PMID:22285177

Switchable multiwavelength fiber laser by using a compact in-fiber Mach–Zehnder interferometer

International Nuclear Information System (INIS)

Zhang, Qianwu; Zeng, Xianglong; Pang, Fufei; Wang, Min; Wang, Tingyun

2012-01-01

We propose a simple and compact method for implementing an in-fiber Mach–Zehnder interferometer, which is constructed with two optical paths, propagating through the core and the ring-shaped silica cladding modes in the double-cladding fibers. Strong cladding-mode resonance across the thin inner cladding is used to excite the cladding modes. The measured spectra fringe presents high-contrast interference from cascading a pair of well-overlapped resonant spectra dips. In combination with the nonlinear polarization rotation (NPR) technique, switchable and tunable multi-channel laser outputs are experimentally demonstrated with a fluctuation of less than 0.1 dB. (paper)

Enhanced Motor Skill Acquisition in the Non-dominant Upper Extremity using Intermittent Theta Burst Stimulation and Transcranial Direct Current Stimulation

Directory of Open Access Journals (Sweden)

Ray eButts

2014-06-01

Full Text Available Individuals suffering from motor impairments often require physical therapy (PT to help improve their level of function. Previous investigations suggest that both intermittent theta burst stimulation (iTBS and bihemispheric transcranial direct current stimulation may increase the speed and extent of motor learning/relearning and that this increase may be related to brain derived neurotrophic factor (BDNF. The purpose of the current study was to explore the feasibility and effectiveness of a novel, non-invasive brain stimulation approach that combined an iTBS primer, and bihemispheric stimulation coupled with motor training. We hypothesized that individuals exposed to this novel treatment would make greater functional improvements than individuals undergoing sham stimulation when tested immediately following, 24-hours, and 7-days post-training. A total of 26 right-handed, healthy young adults were randomly assigned to either a treatment (n = 15 or control group (n = 12. iTBS (20 trains of 10 pulse triplets each delivered at 80% AMT / 50Hz over 191.84 seconds and bihemispheric tDCS (1.0 ma for 20 minutes were used as a primer to, and in conjunction with, 20 minutes of motor training, respectively. Our primary outcome measure was performance on the Jebsen-Taylor Hand Function Test. Participants tolerated the combined iTBS/bihemispheric stimulation treatment without complaint. While performance gains in the sham and stimulation group were not significant immediately after training, they were nearly significant 24-hours post training (p = 0.055, and were significant at 7-days post training (p < 0.05. These results suggest that the combined iTBS/bihemispheric stimulation protocol is both feasible and effective. Future research should examine the mechanistic explanation of this approach as well as the potential of using this approach in clinical populations.

Transient basilar artery occlusion monitored by transcranial color Doppler presenting with a spectacular shrinking deficit: a case report

Directory of Open Access Journals (Sweden)

Del Sette Massimo

2010-01-01

Full Text Available Abstract Introduction We describe the case of a 79-year-old Caucasian Italian woman with a transient basilar occlusion monitored by transcranial Doppler, with subsequent recanalization and clinical shrinking deficit. This is the first case of transient basilar occlusive disease diagnosed and monitored by transcranial Doppler. This case is important and needs to be reported because transient basilar occlusion may be easily diagnosed if transcranial Doppler is performed. Case presentation A 79-year-old woman affected by chronic atrial fibrillation and not treated with oral anticoagulants, cardioverted to sinus rhythm during a gastric endoscopy. She then showed a sudden-onset loss of consciousness, horizontal and vertical gaze palsy, tetraparesis and bilateral miosis and coma. Two hours later, the symptoms resolved quickly, leaving no residual neurologic deficits. Transcranial Doppler examination showed a dampened flow in the basilar artery in the emergency examination and a restored flow when the symptoms resolved. Conclusion This is the first case of transient basilar occlusive disease diagnosed and monitored by transcranial Doppler. We believe that transcranial Doppler should be performed in all cases of unexplained acute loss of consciousness, in particular, if associated with signs of brainstem dysfunctions.

Statistical electron angular correlation coefficients for atoms within the Hohenberg-Kohn-Sham theory

International Nuclear Information System (INIS)

Pathak, R.K.

1985-01-01

Statistical electron angular correlation coefficients tau = 2 2 He through 14 Si, within the Hohenberg-Kohn-Sham density-functional formalism. These are computed with use of the spectral sum rules obtained from the pseudoexcitation spectrum employing the recent formulation of the time-dependent Kohn-Sham theory due to Bartolotti. Various approximations to the exchange-correlation energy functional are used and for first-row atoms, a comparison is made with the highly accurate correlation coefficients recently obtained by Thakkar. The present tau values show closer agreement with those of Thakkar with increasing number of electrons

No effect of anodal transcranial direct current stimulation over the motor cortex on response-related ERPs during a conflict task.

Directory of Open Access Journals (Sweden)

Alexander Christian Conley

2016-08-01

Full Text Available Anodal transcranial direct current stimulation (tDCS over the motor cortex is considered a potential treatment for motor rehabilitation following stroke and other neurological pathologies. However, both the context under which this stimulation is effective and the underlying mechanisms remain to be determined. In this study, we examined the mechanisms by which anodal tDCS may affect motor performance by recording event-related potentials (ERPs during a cued go/nogo task after anodal tDCS over dominant M1 in young adults (Experiment 1 and both dominant and non-dominant M1 in old adults (Experiment 2. In both experiments, anodal tDCS had no effect on either response time or response-related ERPs, including the cue-locked contingent negative variation (CNV and both target-locked and response-locked lateralised readiness potentials (LRP. Bayesian model selection analyses showed that, for all measures, the null effects model was stronger than a model including anodal tDCS vs. sham. We conclude that anodal tDCS has no effect on response time or response-related ERPs during a cued go/nogo task in either young or old adults.

Transcranial Direct Current Stimulation Does Not Influence the Speed-Accuracy Tradeoff in Perceptual Decision-making: Evidence from Three Independent Studies.

Science.gov (United States)

de Hollander, Gilles; Labruna, Ludovica; Sellaro, Roberta; Trutti, Anne; Colzato, Lorenza S; Ratcliff, Roger; Ivry, Richard B; Forstmann, Birte U

2016-09-01

In perceptual decision-making tasks, people balance the speed and accuracy with which they make their decisions by modulating a response threshold. Neuroimaging studies suggest that this speed-accuracy tradeoff is implemented in a corticobasal ganglia network that includes an important contribution from the pre-SMA. To test this hypothesis, we used anodal transcranial direct current stimulation (tDCS) to modulate neural activity in pre-SMA while participants performed a simple perceptual decision-making task. Participants viewed a pattern of moving dots and judged the direction of the global motion. In separate trials, they were cued to either respond quickly or accurately. We used the diffusion decision model to estimate the response threshold parameter, comparing conditions in which participants received sham or anodal tDCS. In three independent experiments, we failed to observe an influence of tDCS on the response threshold. Additional, exploratory analyses showed no influence of tDCS on the duration of nondecision processes or on the efficiency of information processing. Taken together, these findings provide a cautionary note, either concerning the causal role of pre-SMA in decision-making or on the utility of tDCS for modifying response caution in decision-making tasks.

What Do We Know About the Influence of the Cerebellum on Walking Ability? Promising Findings from Transcranial Alternating Current Stimulation.

Science.gov (United States)

Naro, Antonino; Milardi, Demetrio; Cacciola, Alberto; Russo, Margherita; Sciarrone, Francesca; La Rosa, Gianluca; Bramanti, Alessia; Bramanti, Placido; Calabrò, Rocco Salvatore

2017-08-01

Several cerebellar functions related to upper limb motor control have been studied using non-invasive brain stimulation paradigms. We have recently shown that transcranial alternating current stimulation (tACS) may be a promising approach in shaping the plasticity of cerebellum-brain pathways in a safe and effective manner. This study aimed to assess whether cerebellar tACS at different frequencies may tune M1-leg excitability and modify gait control in healthy human subjects. To this end, we tested the effects of different cerebellar tACS frequencies over the right cerebellar hemisphere (at 10, 50, and 300 Hz, besides a sham-tACS) on M1-leg excitability, cerebellum-brain inhibition (CBI), and gait parameters in a sample of 25 healthy volunteers. Fifty and 300 Hz tACS differently modified M1-leg excitability and CBI from both lower limbs, without significant gait perturbations. We hypothesize that tACS aftereffect may depend on a selective entrainment of distinct cerebellar networks related to lower limb motor functions. Therefore, cerebellar tACS might represent a useful tool to modulate walking training in people with cerebellum-related gait impairment, given that tACS may potentially reset abnormal cerebellar circuitries.

A single session of prefrontal cortex transcranial direct current stimulation does not modulate implicit task sequence learning and consolidation.

Science.gov (United States)

Savic, Branislav; Müri, René; Meier, Beat

Transcranial direct current stimulation (tDCS) is assumed to affect cortical excitability and dependent on the specific stimulation conditions either to increase or decrease learning. The purpose of this study was to modulate implicit task sequence learning with tDCS. As cortico-striatal loops are critically involved in implicit task sequence learning, tDCS was applied above the dorsolateral prefrontal cortex (DLPFC). In Experiment 1, anodal, cathodal, or sham tDCS was applied before the start of the sequence learning task. In Experiment 2, stimulation was applied during the sequence learning task. Consolidation of learning was assessed after 24 h. The results of both experiments showed that implicit task sequence learning occurred consistently but it was not modulated by different tDCS conditions. Similarly, consolidation measured after a 24 h-interval including sleep was also not affected by stimulation. These results indicate that a single session of DLPFC tDCS is not sufficient to modulate implicit task sequence learning. This study adds to the accumulating evidence that tDCS may not be as effective as originally thought. Copyright © 2017 Elsevier Inc. All rights reserved.

Clinical utility of carotid and transcranial ultrasound in cerebrovascular diseases

Directory of Open Access Journals (Sweden)

Figueiredo L

2014-08-01

Full Text Available Lívia Figueiredo, Viviane F Zétola, Marcos C Lange Neurology Division, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil Abstract: Carotid and transcranial (CTU ultrasound is a useful tool in a number of clinical settings, particularly in cerebrovascular diseases. CTU is the only method that provides real-time determination of velocity and the spectral waveform of blood flow in the extracranial and basal intracranial arteries, and is effective in the detection of stenosis and occlusion. When transcranial ultrasound is considered, CTU is the only method that allows visualization of microembolic signals in the intracranial arteries. CTU makes a rapid differential diagnosis possible, improving therapeutic decision-making in acute stroke and determining the risk of recurrence and prognosis based on its findings. It is also the standard of care in children with sickle cell disease, when selecting patients for chronic blood transfusion, and for reducing the risk of ischemic stroke in these patients. CTU has some advantages, ie, relative simplicity in terms of interpretation and performance, and affordability, noninvasiveness, and portability. The main concern with ultrasound is that it is an operator-dependent tool and requires a high level of expertise and knowledge of three-dimensional cerebrovascular anatomy for correct interpretation of sonograms. The most significant limitation of intracranial evaluation by transcranial ultrasound is the absence of a suitable bone window in approximately 10% of patients. This paper gives an overview of the current utility and importance of CTU in the prevention and evaluation of ischemic cerebrovascular disease. Keywords: transcranial Doppler ultrasonography, Doppler ultrasonography duplex, cerebrovascular disorders, stroke

A spectral scheme for Kohn-Sham density functional theory of clusters

Science.gov (United States)

Banerjee, Amartya S.; Elliott, Ryan S.; James, Richard D.

2015-04-01

Starting from the observation that one of the most successful methods for solving the Kohn-Sham equations for periodic systems - the plane-wave method - is a spectral method based on eigenfunction expansion, we formulate a spectral method designed towards solving the Kohn-Sham equations for clusters. This allows for efficient calculation of the electronic structure of clusters (and molecules) with high accuracy and systematic convergence properties without the need for any artificial periodicity. The basis functions in this method form a complete orthonormal set and are expressible in terms of spherical harmonics and spherical Bessel functions. Computation of the occupied eigenstates of the discretized Kohn-Sham Hamiltonian is carried out using a combination of preconditioned block eigensolvers and Chebyshev polynomial filter accelerated subspace iterations. Several algorithmic and computational aspects of the method, including computation of the electrostatics terms and parallelization are discussed. We have implemented these methods and algorithms into an efficient and reliable package called ClusterES (Cluster Electronic Structure). A variety of benchmark calculations employing local and non-local pseudopotentials are carried out using our package and the results are compared to the literature. Convergence properties of the basis set are discussed through numerical examples. Computations involving large systems that contain thousands of electrons are demonstrated to highlight the efficacy of our methodology. The use of our method to study clusters with arbitrary point group symmetries is briefly discussed.

Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording

Directory of Open Access Journals (Sweden)

James eDowsett

2016-03-01

Full Text Available Transcranial alternating current stimulation (tACS has until now mostly been administered as an alternating sinusoidal wave. Despite modern tACS stimulators being able to deliver alternating current with any arbitrary shape there has been no systematic exploration into the relative benefits of different waveforms. As tACS is a relatively new technique there is a huge parameter space of unexplored possibilities which may prove superior or complimentary to the traditional sinusoidal waveform. Here we begin to address this with an investigation into the effects of sawtooth wave tACS on individual alpha power. Evidence from animal models suggests that the gradient and direction of an electric current should be important factors for the subsequent neural firing rate; we compared positive and negative ramp sawtooth waves to test this. An additional advantage of sawtooth waves is that the resulting artefact in the electroencephalogram (EEG recording is significantly simpler to remove than a sine wave; accordingly we were able to observe alpha oscillations both during and after stimulation.We found that positive ramp sawtooth, but not negative ramp sawtooth, significantly enhanced alpha power during stimulation relative to sham (p<0.01. In addition we tested for an after-effect of both sawtooth and sinusoidal stimulation on alpha power but in this case did not find any significant effect. This preliminary study paves the way for further investigations into the effect of the gradient and direction of the current in tACS which could significantly improve the usefulness of this technique.

Low-frequency transcranial magnetic stimulation is beneficial for enhancing synaptic plasticity in the aging brain

Directory of Open Access Journals (Sweden)

Zhan-chi Zhang

2015-01-01

Full Text Available In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz ameliorates synaptic plasticity and spatial cognitive deficits in learning-impaired mice. However, the mechanisms by which this treatment improves these deficits during normal aging are still unknown. Therefore, the current study investigated the effects of transcranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, synaptophysin and growth-associated protein 43 (both synaptic markers, to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcranial magnetic stimulation with low intensity (110% average resting motor threshold intensity, 1 Hz increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippocampus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this regulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

Effect of anatomical variability in brain on transcranial magnetic stimulation treatment

Science.gov (United States)

Syeda, F.; Magsood, H.; Lee, E. G.; El-Gendy, A. A.; Jiles, D. C.; Hadimani, R. L.

2017-05-01

Transcranial Magnetic Stimulation is a non-invasive clinical therapy used to treat depression and migraine, and shows further promise as treatment for Parkinson's disease, Alzheimer's disease, and other neurological disorders. However, it is yet unclear as to how anatomical differences may affect stimulation from this treatment. We use finite element analysis to model and analyze the results of Transcranial Magnetic Stimulation in various head models. A number of heterogeneous head models have been developed using MRI data of real patients, including healthy individuals as well as patients of Parkinson's disease. Simulations of Transcranial Magnetic Stimulation performed on 22 anatomically different models highlight the differences in induced stimulation. A standard Figure of 8 coil is used with frequency 2.5 kHz, placed 5 mm above the head. We compare cortical stimulation, volume of brain tissue stimulated, specificity, and maximum E-field induced in the brain for models ranging from ages 20 to 60. Results show that stimulation varies drastically between patients of the same age and health status depending upon brain-scalp distance, which is not necessarily a linear progression with age.

Effect of Continuous Positive Airway Pressure on Stroke Rehabilitation: A Pilot Randomized Sham-Controlled Trial

Science.gov (United States)

Khot, Sandeep P.; Davis, Arielle P.; Crane, Deborah A.; Tanzi, Patricia M.; Li Lue, Denise; Claflin, Edward S.; Becker, Kyra J.; Longstreth, W.T.; Watson, Nathaniel F.; Billings, Martha E.

2016-01-01

Study Objectives: Obstructive sleep apnea (OSA) predicts poor functional outcome after stroke and increases the risk for recurrent stroke. Less is known about continuous positive airway pressure (CPAP) treatment on stroke recovery. Methods: In a pilot randomized, double-blind, sham-controlled trial, adult stroke rehabilitation patients were assigned to auto-titrating or sham CPAP without diagnostic testing for OSA. Change in Functional Independence Measure (FIM), a measure of disability, was assessed between rehabilitation admission and discharge. Results: Over 18 months, 40 patients were enrolled and 10 withdrew from the study: 7 from active and 3 from sham CPAP (p > 0.10). For the remaining 30 patients, median duration of CPAP use was 14 days. Average CPAP use was 3.7 h/night, with at least 4 h nightly use among 15 patients. Adherence was not influenced by treatment assignment or stroke severity. In intention-to-treat analyses (n = 40), the median change in FIM favored active CPAP over sham but did not reach statistical significance (34 versus 26, p = 0.25), except for the cognitive component (6 versus 2.5, p = 0.04). The on-treatment analyses (n = 30) yielded similar results (total FIM: 32 versus 26, p = 0.11; cognitive FIM: 6 versus 2, p = 0.06). Conclusions: A sham-controlled CPAP trial among stroke rehabilitation patients was feasible in terms of recruitment, treatment without diagnostic testing and adequate blinding—though was limited by study retention and CPAP adherence. Despite these limitations, a trend towards a benefit of CPAP on recovery was evident. Tolerance and adherence must be improved before the full benefits of CPAP on recovery can be assessed in larger trials. Citation: Khot SP, Davis AP, Crane DA, Tanzi PM, Li Lue D, Claflin ES, Becker KJ, Longstreth WT, Watson NF, Billings ME. Effect of continuous positive airway pressure on stroke rehabilitation: a pilot randomized sham-controlled trial. J Clin Sleep Med 2016;12(7):1019–1026. PMID

Parameter-Based Evaluation of Attentional Impairments in Schizophrenia and Their Modulation by Prefrontal Transcranial Direct Current Stimulation

Directory of Open Access Journals (Sweden)

Nadine Gögler

2017-11-01

Full Text Available BackgroundAttentional dysfunctions constitute core cognitive symptoms in schizophrenia, but the precise underlying neurocognitive mechanisms remain to be elucidated.MethodsIn this randomized, double-blind, sham-controlled study, we applied, for the first time, a theoretically grounded modeling approach based on Bundesen’s Theory of Visual Attention (TVA to (i identify specific visual attentional parameters affected in schizophrenia and (ii assess, as a proof of concept, the potential of single-dose anodal transcranial direct current stimulation (tDCS; 20 min, 2 mA to the left dorsolateral prefrontal cortex to modulate these attentional parameters. To that end, attentional parameters were measured before (baseline, immediately after, and 24 h after the tDCS intervention in 20 schizophrenia patients and 20 healthy controls.ResultsAt baseline, analyses revealed significantly reduced visual processing speed and visual short-term memory storage capacity in schizophrenia. A significant stimulation condition × time point interaction in the schizophrenia patient group indicated improved processing speed at the follow-up session only in the sham condition (a practice effect, whereas performance remained stable across the three time points in patients receiving verum stimulation. In healthy controls, anodal tDCS did not result in a significant change in attentional performance.ConclusionWith regard to question (i above, these findings are indicative of a processing speed and short-term memory deficit as primary sources of attentional deficits in schizophrenia. With regard to question (ii, the efficacy of single-dose anodal tDCS for improving (speed aspects of visual cognition, it appears that prefrontal tDCS (at the settings used in the present study, rather than ameliorating the processing speed deficit in schizophrenia, actually may interfere with practice-dependent improvements in the rate of visual information uptake. Such potentially

A novel decision tree approach based on transcranial Doppler sonography to screen for blunt cervical vascular injuries.

Science.gov (United States)

Purvis, Dianna; Aldaghlas, Tayseer; Trickey, Amber W; Rizzo, Anne; Sikdar, Siddhartha

2013-06-01

Early detection and treatment of blunt cervical vascular injuries prevent adverse neurologic sequelae. Current screening criteria can miss up to 22% of these injuries. The study objective was to investigate bedside transcranial Doppler sonography for detecting blunt cervical vascular injuries in trauma patients using a novel decision tree approach. This prospective pilot study was conducted at a level I trauma center. Patients undergoing computed tomographic angiography for suspected blunt cervical vascular injuries were studied with transcranial Doppler sonography. Extracranial and intracranial vasculatures were examined with a portable power M-mode transcranial Doppler unit. The middle cerebral artery mean flow velocity, pulsatility index, and their asymmetries were used to quantify flow patterns and develop an injury decision tree screening protocol. Student t tests validated associations between injuries and transcranial Doppler predictive measures. We evaluated 27 trauma patients with 13 injuries. Single vertebral artery injuries were most common (38.5%), followed by single internal carotid artery injuries (30%). Compared to patients without injuries, mean flow velocity asymmetry was higher for single internal carotid artery (P = .003) and single vertebral artery (P = .004) injuries. Similarly, pulsatility index asymmetry was higher in single internal carotid artery (P = .015) and single vertebral artery (P = .042) injuries, whereas the lowest pulsatility index was elevated for bilateral vertebral artery injuries (P = .006). The decision tree yielded 92% specificity, 93% sensitivity, and 93% correct classifications. In this pilot feasibility study, transcranial Doppler measures were significantly associated with the blunt cervical vascular injury status, suggesting that transcranial Doppler sonography might be a viable bedside screening tool for trauma. Patient-specific hemodynamic information from transcranial Doppler assessment has the potential to alter

Randomized sham-controlled trial of renal sympathetic denervation in mild resistant hypertension.

Science.gov (United States)

Desch, Steffen; Okon, Thomas; Heinemann, Diana; Kulle, Konrad; Röhnert, Karoline; Sonnabend, Melanie; Petzold, Martin; Müller, Ulrike; Schuler, Gerhard; Eitel, Ingo; Thiele, Holger; Lurz, Philipp

2015-06-01

Few data are available with regard to the effectiveness of renal sympathetic denervation in patients with resistant hypertension yet only mildly elevated blood pressure (BP). Patients with resistant hypertension and slightly elevated BP (day-time systolic pressure, 135-149 and diastolic pressure, 90-94 mm Hg on 24-hour ambulatory measurement) were randomized in a 1:1 ratio to renal sympathetic denervation with the Symplicity Flex Catheter (Medtronic) or an invasive sham procedure. The primary efficacy end point was the change in 24-hour systolic BP at 6 months between groups in the intention to treat population. A total of 71 patients underwent randomization. Baseline day-time systolic BP was 144.4±4.8 mm Hg in patients assigned to denervation and 143.0±4.7 mm Hg in patients randomized to the sham procedure. The mean change in 24-hour systolic BP in the intention to treat cohort at 6 months was -7.0 mm Hg (95% confidence interval, -10.8 to -3.2) for patients undergoing denervation and -3.5 mm Hg (95% confidence interval, -6.7 to -0.2) in the sham group (P=0.15). In the per protocol population, the change in 24-hour systolic BP at 6 months was -8.3 mm Hg (95% confidence interval, -11.7 to -5.0) for patients undergoing denervation and -3.5 mm Hg (95% confidence interval, -6.8 to -0.2) in the sham group (P=0.042). In patients with mild resistant hypertension, renal sympathetic denervation failed to show a significant reduction in the primary end point of 24-hour systolic BP at 6 months between groups in the intention to treat analysis. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01656096. © 2015 American Heart Association, Inc.

Development and characterization of amorphous acrylate networks for use as switchable adhesives inspired from shapememory behavior

Science.gov (United States)

Lakhera, Nishant

Several types of insects and animals such as spiders and geckos are inherently able to climb along vertical walls and ceilings. This remarkable switchable adhesive behavior has been attributed to the fibrillar structures on their feet, with size ranging from few nanometers to a few micrometers depending on the species. Several studies have attempted to create synthetic micro-patterned surfaces trying to imitate this adhesive behavior seen in nature. The experimental procedures are scattered, with sole purpose of trying to increase adhesion, thereby making direct comparison between studies very difficult. There is a lack of fundamental understanding on adhesion of patterned surfaces. The influence of critical parameters like material modulus, glass transition temperature, viscoelastic effects, temperature and water absorption on adhesion is not fully explored and characterized. These parameters are expected to have a decisive influence on adhesion behavior of the polymer. Previous studies have utilized conventional "off-the-shelf" materials like epoxy, polyurethanes etc. It is however, impossible to change the material modulus, glass transition temperature etc. of these polymer systems without changing the base constituents itself, thereby explaining the gaps in the current research landscape. The purpose of this study was to use acrylate shape-memory polymers (SMPs) for their ability to be tailored to specific mechanical properties by control of polymer chemistry, without changing the base constituents. Polymer networks with tailorable glass transition, material modulus, water absorption etc. were developed and adhesion studies were performed to investigate the influence of temperature, viscoelastic effects, material modulus on the adhesion behavior of flat acrylate polymer surfaces. The knowledge base gained from these studies was utilized to better understand the fundamental mechanisms associated with adhesion behavior of patterned acrylate surfaces. Thermally

Transcranial direct current stimulation (tDCS) Paired with massed practice training to promote adaptive plasticity and motor recovery in chronic incomplete tetraplegia: a pilot study.

Science.gov (United States)

Potter-Baker, Kelsey A; Janini, Daniel P; Lin, Yin-Liang; Sankarasubramanian, Vishwanath; Cunningham, David A; Varnerin, Nicole M; Chabra, Patrick; Kilgore, Kevin L; Richmond, Mary Ann; Frost, Frederick S; Plow, Ela B

2017-08-07

Objective Our goal was to determine if pairing transcranial direct current stimulation (tDCS) with rehabilitation for two weeks could augment adaptive plasticity offered by these residual pathways to elicit longer-lasting improvements in motor function in incomplete spinal cord injury (iSCI). Design Longitudinal, randomized, controlled, double-blinded cohort study. Setting Cleveland Clinic Foundation, Cleveland, Ohio, USA. Participants Eight male subjects with chronic incomplete motor tetraplegia. Interventions Massed practice (MP) training with or without tDCS for 2 hrs, 5 times a week. Outcome Measures We assessed neurophysiologic and functional outcomes before, after and three months following intervention. Neurophysiologic measures were collected with transcranial magnetic stimulation (TMS). TMS measures included excitability, representational volume, area and distribution of a weaker and stronger muscle motor map. Functional assessments included a manual muscle test (MMT), upper extremity motor score (UEMS), action research arm test (ARAT) and nine hole peg test (NHPT). Results We observed that subjects receiving training paired with tDCS had more increased strength of weak proximal (15% vs 10%), wrist (22% vs 10%) and hand (39% vs. 16%) muscles immediately and three months after intervention compared to the sham group. Our observed changes in muscle strength were related to decreases in strong muscle map volume (r=0.851), reduced weak muscle excitability (r=0.808), a more focused weak muscle motor map (r=0.675) and movement of weak muscle motor map (r=0.935). Conclusion Overall, our results encourage the establishment of larger clinical trials to confirm the potential benefit of pairing tDCS with training to improve the effectiveness of rehabilitation interventions for individuals with SCI. Trial Registration NCT01539109.

[Transcranial magnetotherapy for the correction of initial manifestations of diabetic retinopathy in children].

Science.gov (United States)

Nikolaeva, N V; Bolotova, N V; Kamenskikh, T G; Raĭgorodskiĭ, Iu M; Kolbenev, I O; Luk'ianov, V F

2009-01-01

This study included 45 children at the age from 5 to 17 years with type I diabetes mellitus complicated by diabetic retinopathy. All the patients showed retinal thickening at the macula and reduced amplitude of local electroretinogram suggesting compromised capillary circulation. The capillary blood flow was corrected by transcranial magnetotherapy with the use of an AMO-ATOS Ogolovie unit. The results of the treatment were evaluated from characteristics of laser Doppler flometry. A course of transcranial magnetotherapy comprising 10 daily seances resulted in a significant increase of microcirculation index, respiratory rhythm, and myogenic tone (by 1.64, 1.35, and 1.16 times respectively). In addition, morphometric and electrophysiological properties of the retina underwent positive changes. Transcranial exposure to the traveling magnetic field is recommended for the correction of intraocular microcirculation and prevention of diabetic macular oedema.

Concurrent transcranial direct current stimulation and progressive resistance training in Parkinson's disease: study protocol for a randomised controlled trial.

Science.gov (United States)

Hendy, Ashlee M; Tillman, Alex; Rantalainen, Timo; Muthalib, Makii; Johnson, Liam; Kidgell, Dawson J; Wundersitz, Daniel; Enticott, Peter G; Teo, Wei-Peng

2016-07-19

Parkinson's disease (PD) results from a loss of dopamine in the brain, leading to movement dysfunctions such as bradykinesia, postural instability, resting tremor and muscle rigidity. Furthermore, dopamine deficiency in PD has been shown to result in maladaptive plasticity of the primary motor cortex (M1). Progressive resistance training (PRT) is a popular intervention in PD that improves muscular strength and results in clinically significant improvements on the Unified Parkinson's Disease Rating Scale (UPDRS). In separate studies, the application of anodal transcranial direct current stimulation (a-tDCS) to the M1 has been shown to improve motor function in PD; however, the combined use of tDCS and PRT has not been investigated. We propose a 6-week, double-blind randomised controlled trial combining M1 tDCS and PRT of the lower body in participants (n = 42) with moderate PD (Hoehn and Yahr scale score 2-4). Supervised lower body PRT combined with functional balance tasks will be performed three times per week with concurrent a-tDCS delivered at 2 mA for 20 minutes (a-tDCS group) or with sham tDCS (sham group). Control participants will receive standard care (control group). Outcome measures will include functional strength, gait speed and variability, balance, neurophysiological function at rest and during movement execution, and the UPDRS motor subscale, measured at baseline, 3 weeks (during), 6 weeks (post), and 9 weeks (retention). Ethical approval has been granted by the Deakin University Human Research Ethics Committee (project number 2015-014), and the trial has been registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615001241527). This will be the first randomised controlled trial to combine PRT and a-tDCS targeting balance and gait in people with PD. The study will elucidate the functional, clinical and neurophysiological outcomes of combined PRT and a-tDCS. It is hypothesised that combined PRT and a-tDCS will significantly

Renal denervation in treatment-resistant essential hypertension. A randomized, SHAM-controlled, double-blinded 24-h blood pressure-based trial.

Science.gov (United States)

Mathiassen, Ole N; Vase, Henrik; Bech, Jesper N; Christensen, Kent L; Buus, Niels H; Schroeder, Anne P; Lederballe, Ole; Rickers, Hans; Kampmann, Ulla; Poulsen, Per L; Hansen, Klavs W; Btker, Hans E; Peters, Christian D; Engholm, Morten; Bertelsen, Jannik B; Lassen, Jens F; Langfeldt, Sten; Andersen, Gratien; Pedersen, Erling B; Kaltoft, Anne

2016-08-01

Renal denervation (RDN), treating resistant hypertension, has, in open trial design, been shown to lower blood pressure (BP) dramatically, but this was primarily with respect to office BP. We conducted a SHAM-controlled, double-blind, randomized, single-center trial to establish efficacy data based on 24-h ambulatory BP measurements (ABPM). Inclusion criteria were daytime systolic ABPM at least 145 mmHg following 1 month of stable medication and 2 weeks of compliance registration. All RDN procedures were carried out by an experienced operator using the unipolar Medtronic Flex catheter (Medtronic, Santa Rosa, California, USA). We randomized 69 patients with treatment-resistant hypertension to RDN (n = 36) or SHAM (n = 33). Groups were well balanced at baseline. Mean baseline daytime systolic ABPM was 159 ± 12 mmHg (RDN) and 159 ± 14 mmHg (SHAM). Groups had similar reductions in daytime systolic ABPM compared with baseline at 3 months [-6.2 ± 18.8 mmHg (RDN) vs. -6.0 ± 13.5 mmHg (SHAM)] and at 6 months [-6.1 ± 18.9 mmHg (RDN) vs. -4.3 ± 15.1 mmHg (SHAM)]. Mean usage of antihypertensive medication (daily defined doses) at 3 months was equal [6.8 ± 2.7 (RDN) vs. 7.0 ± 2.5 (SHAM)].RDN performed at a single center and by a high-volume operator reduced ABPM to the same level as SHAM treatment and thus confirms the result of the HTN3 trial. Further, clinical use of RDN for treatment of resistant hypertension should await positive results from double-blinded, SHAM-controlled trials with multipolar ablation catheters or novel denervation techniques.

A Review of Repetitive Transcranial Magnetic Stimulation Use in Psychiatry

Directory of Open Access Journals (Sweden)

Onur Durmaz

2013-08-01

Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a non-invasive brain stimulation technique first introduced by Barker et al. in 1985. The principle of rTMS is based on a cortical neuronal transmembrane potential stimulated by a pulsative magnetic field. This magnetic field is induced by a direct electrical current sent through a circular coil. rTMS is an effective and widely used therapeutic stimulation method for psychiatric disorders, primarily for unipolar depression. Cost-effectiveness, minor side effects and well-tolerated profile of rTMS with no need to hospitalization for administation are the prominent features of this method. Beside the information for depression, rTMS has been reported to have some remarkable impacts in alleviating symptoms of anxiety disorders. Although data regarding efficacy of rTMS in anxiety disorders is conflicting, there are positive outcomes about generalized anxiety disorder, post-traumatic stress disorder and panic disorder whereas results of rTMS treatment in obsessive-compulsive disorder are generally not favorable. Since low frequency stimulation techniques have been found to be effective in treatment of auditory hallucinations, methodological similarity in concerned studies could be accepted as a supportive aspect of efficacy. Additionally, high frequency stimulation techniques applied to prefrontal area have a potential to impact negative symptoms of schizophrenia. With improving novel techniques of this stimulation method, rTMS is being used increasingly in psychiatric disorders. However, some issues concerning rTMS treatment such as maintenance or prophilactic therapy procedures, duration of effect are remain unclear. Hence, we conclude that multicenter sham controlled studies including similar designs, sociodemographic and clinical variables, methodological protocols with larger sample sizes and studies guieded by imaging methods are warranted to determinate efficacy and side effects of rTMS use

Tunable and switchable multi-wavelength erbium-doped fiber laser with highly nonlinear photonic crystal fiber and polarization controllers

International Nuclear Information System (INIS)

Liu, X M; Lin, A; Zhao, W; Lu, K Q; Wang, Y S; Zhang, T Y; Chung, Y

2008-01-01

We have proposed a novel multi-wavelength erbium-doped fiber laser by using two polarization controllers and a sampled chirped fiber Bragg grating(SC-FBG). On the assistance of SC-FBG, the proposed fiber lasers with excellent stability and uniformity are tunable and switchable by adjusting the polarization controllers. Our laser can stably lase two waves and up to eight waves simultaneously at room temperature

A spectral scheme for Kohn–Sham density functional theory of clusters

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Amartya S., E-mail: baner041@umn.edu; Elliott, Ryan S., E-mail: relliott@umn.edu; James, Richard D., E-mail: james@umn.edu

2015-04-15

Starting from the observation that one of the most successful methods for solving the Kohn–Sham equations for periodic systems – the plane-wave method – is a spectral method based on eigenfunction expansion, we formulate a spectral method designed towards solving the Kohn–Sham equations for clusters. This allows for efficient calculation of the electronic structure of clusters (and molecules) with high accuracy and systematic convergence properties without the need for any artificial periodicity. The basis functions in this method form a complete orthonormal set and are expressible in terms of spherical harmonics and spherical Bessel functions. Computation of the occupied eigenstates of the discretized Kohn–Sham Hamiltonian is carried out using a combination of preconditioned block eigensolvers and Chebyshev polynomial filter accelerated subspace iterations. Several algorithmic and computational aspects of the method, including computation of the electrostatics terms and parallelization are discussed. We have implemented these methods and algorithms into an efficient and reliable package called ClusterES (Cluster Electronic Structure). A variety of benchmark calculations employing local and non-local pseudopotentials are carried out using our package and the results are compared to the literature. Convergence properties of the basis set are discussed through numerical examples. Computations involving large systems that contain thousands of electrons are demonstrated to highlight the efficacy of our methodology. The use of our method to study clusters with arbitrary point group symmetries is briefly discussed.

A spectral scheme for Kohn–Sham density functional theory of clusters

International Nuclear Information System (INIS)

Banerjee, Amartya S.; Elliott, Ryan S.; James, Richard D.

2015-01-01

Starting from the observation that one of the most successful methods for solving the Kohn–Sham equations for periodic systems – the plane-wave method – is a spectral method based on eigenfunction expansion, we formulate a spectral method designed towards solving the Kohn–Sham equations for clusters. This allows for efficient calculation of the electronic structure of clusters (and molecules) with high accuracy and systematic convergence properties without the need for any artificial periodicity. The basis functions in this method form a complete orthonormal set and are expressible in terms of spherical harmonics and spherical Bessel functions. Computation of the occupied eigenstates of the discretized Kohn–Sham Hamiltonian is carried out using a combination of preconditioned block eigensolvers and Chebyshev polynomial filter accelerated subspace iterations. Several algorithmic and computational aspects of the method, including computation of the electrostatics terms and parallelization are discussed. We have implemented these methods and algorithms into an efficient and reliable package called ClusterES (Cluster Electronic Structure). A variety of benchmark calculations employing local and non-local pseudopotentials are carried out using our package and the results are compared to the literature. Convergence properties of the basis set are discussed through numerical examples. Computations involving large systems that contain thousands of electrons are demonstrated to highlight the efficacy of our methodology. The use of our method to study clusters with arbitrary point group symmetries is briefly discussed