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Sample records for anodal transcranial direct

  1. Counteracting fatigue in multiple sclerosis with right parietal anodal transcranial direct current stimulation

    NARCIS (Netherlands)

    Hanken, K.; Bosse, M.; Möhrke, K.; Eling, P.A.T.M.; Kastrup, A.; Antal, A.; Hildebrandt, H.

    2016-01-01

    Background: Fatigue in multiple sclerosis (MS) patients appears to correlate with vigilance decrement as reflected in an increase in reaction time and errors with prolonged time-on-task. Objectives: The aim of this study was to investigate whether anodal transcranial direct current stimulation

  2. Anodal transcranial direct current stimulation over the supramarginal gyrus facilitates pitch memory.

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    Schaal, Nora K; Williamson, Victoria J; Banissy, Michael J

    2013-11-01

    Functional neuroimaging studies have shown activation of the supramarginal gyrus during pitch memory tasks. A previous transcranial direct current stimulation study using cathodal stimulation over the left supramarginal gyrus reported a detrimental effect on short-term pitch memory performance, indicating an important role of the supramarginal gyrus in pitch memory. The current study aimed to determine whether pitch memory could be improved following anodal stimulation of the left supramarginal gyrus. The performances of non-musicians on two pitch memory tasks (pitch recognition and recall) and a visual memory control task following anodal or sham transcranial direct current stimulation were compared. The results show that, post-stimulation, the anodal group but not the control group performed significantly better on both pitch memory tasks; performance did not differ on the face memory task. These findings provide strong support for the causal involvement of the left supramarginal gyrus in the pitch memory process, and highlight the potential efficacy of transcranial direct current stimulation as a tool to improve pitch memory. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  3. Acute changes in motor cortical excitability during slow oscillatory and constant anodal transcranial direct current stimulation

    DEFF Research Database (Denmark)

    Bergmann, Til Ole; Groppa, Sergiu; Seeger, Markus

    2009-01-01

    at 20 min) of either anodal so-tDCS or constant tDCS (c-tDCS) to the primary motor hand area during quiet wakefulness. Simultaneously and time-locked to different phase angles of the slow oscillation, motor-evoked potentials (MEPs) as an index of corticospinal excitability were obtained...... individuals we used on-line single-pulse transcranial magnetic stimulation (TMS) to search for systematic shifts in corticospinal excitability during anodal sleeplike 0.8-Hz slow oscillatory transcranial direct current stimulation (so-tDCS). In separate sessions, we repeatedly applied 30-s trials (two blocks...... in the contralateral hand muscles 10, 20, and 30 s after the onset of tDCS. MEPs were also measured off-line before, between, and after both stimulation blocks to detect any lasting excitability shifts. Both tDCS modes increased MEP amplitudes during stimulation with an attenuation of the facilitatory effect toward...

  4. Anodal transcranial direct current stimulation of parietal cortex enhances action naming in Corticobasal Syndrome

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    Rosa eManenti

    2015-04-01

    Full Text Available Background: Corticobasal Syndrome (CBS is a neurodegenerative disorder that overlaps both clinically and neuropathologically with Frontotemporal dementia and is characterized by apraxia, alien limb phenomena, cortical sensory loss, cognitive impairment, behavioural changes and aphasia. It has been recently demonstrated that transcranial direct current stimulation (tDCS improves naming in healthy subjects and in subjects with language deficits.Objective: The aim of the present study was to explore the extent to which anodal transcranial direct current stimulation (anodal tDCS over the parietal cortex (PARC could facilitate naming performance in CBS subjects. Methods: Anodal tDCS was applied to the left and right PARC during object and action naming in seventeen patients with a diagnosis of possible CBS. Participants underwent two sessions of anodal tDCS (left and right and one session of placebo tDCS. Vocal responses were recorded and analyzed for accuracy and vocal Reaction Times (vRTs. Results: A shortening of naming latency for actions was observed only after active anodal stimulation over the left PARC, as compared to placebo and right stimulations. No effects have been reported for accuracy.Conclusions: Our preliminary finding demonstrated that tDCS decreased vocal reaction time during action naming in a sample of patients with CBS. A possible explanation of our results is that anodal tDCS over the left PARC effects the brain network implicated in action observation and representation. Further studies, based on larger patient samples, should be conducted to investigate the usefulness of tDCS as an additional treatment of linguistic deficits in CBS patients.

  5. Anodal transcranial direct current stimulation reduces psychophysically measured surround suppression in the human visual cortex.

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    Daniel P Spiegel

    Full Text Available Transcranial direct current stimulation (tDCS is a safe, non-invasive technique for transiently modulating the balance of excitation and inhibition within the human brain. It has been reported that anodal tDCS can reduce both GABA mediated inhibition and GABA concentration within the human motor cortex. As GABA mediated inhibition is thought to be a key modulator of plasticity within the adult brain, these findings have broad implications for the future use of tDCS. It is important, therefore, to establish whether tDCS can exert similar effects within non-motor brain areas. The aim of this study was to assess whether anodal tDCS could reduce inhibitory interactions within the human visual cortex. Psychophysical measures of surround suppression were used as an index of inhibition within V1. Overlay suppression, which is thought to originate within the lateral geniculate nucleus (LGN, was also measured as a control. Anodal stimulation of the occipital poles significantly reduced psychophysical surround suppression, but had no effect on overlay suppression. This effect was specific to anodal stimulation as cathodal stimulation had no effect on either measure. These psychophysical results provide the first evidence for tDCS-induced reductions of intracortical inhibition within the human visual cortex.

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

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    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.

  7. Anodal transcranial direct current stimulation of the motor cortex increases cortical voluntary activation and neural plasticity.

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    Frazer, Ashlyn; Williams, Jacqueline; Spittles, Michael; Rantalainen, Timo; Kidgell, Dawson

    2016-11-01

    We examined the cumulative effect of 4 consecutive bouts of noninvasive brain stimulation on corticospinal plasticity and motor performance, and whether these responses were influenced by the brain-derived neurotrophic factor (BDNF) polymorphism. In a randomized double-blinded cross-over design, changes in strength and indices of corticospinal plasticity were analyzed in 14 adults who were exposed to 4 consecutive sessions of anodal and sham transcranial direct current stimulation (tDCS). Participants also undertook a blood sample for BDNF genotyping (N = 13). We observed a significant increase in isometric wrist flexor strength with transcranial magnetic stimulation revealing increased corticospinal excitability, decreased silent period duration, and increased cortical voluntary activation compared with sham tDCS. The results show that 4 consecutive sessions of anodal tDCS increased cortical voluntary activation manifested as an improvement in strength. Induction of corticospinal plasticity appears to be influenced by the BDNF polymorphism. Muscle Nerve 54: 903-913, 2016. © 2016 Wiley Periodicals, Inc.

  8. Counteracting fatigue in multiple sclerosis with right parietal anodal transcranial direct current stimulation

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    Katrin Hanken

    2016-09-01

    Full Text Available Background: Fatigue in multiple sclerosis (MS patients appears to correlate with vigilance decrement as reflected in an increase in reaction time and errors with prolonged time-on-task. Objectives: The aim of this study was to investigate whether anodal transcranial direct current stimulation (tDCS over the right parietal or frontal cortex counteracts fatigue-associated vigilance decrement and subjective fatigue. Methods: In study I, a randomized double-blind placebo-controlled study, anodal tDCS (1,5mA was delivered to the right parietal cortex or the right frontal cortex of 52 healthy participants during the first 20min of a 40min lasting visual vigilance task. Study II, also a randomized double-blind placebo-controlled study, investigated the effect of anodal tDCS (1.5mA over the right parietal cortex in 46 MS patients experiencing cognitive fatigue. TDCS was delivered for 20min before patients performed a 20min lasting visual vigilance task.Results: Study I showed that right parietal stimulation, but not right frontal stimulation, counteracts the increase in reaction time associated with vigilance decrement. Hence, only right parietal stimulation was applied to the MS patients in study II. Stimulation had a significant effect on vigilance decrement in mildly to moderately cognitively fatigued MS patients. Vigilance testing significantly increased the feeling of fatigue independent of stimulation.Conclusions: Anodal tDCS over the right parietal cortex can counteract the increase in reaction times during vigilance performance but not the increase in subjective fatigue. This finding is compatible with our model of fatigue in MS, suggesting a dissociation between the feeling and the behavioral characteristics of fatigue.

  9. Effects of Anodal Transcranial Direct Current Stimulation on Visually Guided Learning of Grip Force Control

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    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.

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

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    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.

  11. Does anodal transcranial direct current stimulation modulate sensory perception and pain? A meta-analysis study.

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    Vaseghi, B; Zoghi, M; Jaberzadeh, S

    2014-09-01

    The primary aim of this systematic review was to evaluate the effects of anodal transcranial direct current stimulation (a-tDCS) on sensory (STh) and pain thresholds (PTh) in healthy individuals and pain levels (PL) in patients with chronic pain. Electronic databases were searched for a-tDCS studies. Methodological quality was examined using the PEDro and Downs and Black (D&B) assessment tools. a-tDCS of the primary motor cortex (M1) increases both STh (P<0.005, with the effect size of 22.19%) and PTh (P<0.001, effect size of 19.28%). In addition, STh was increased by a-tDCS of the primary sensory cortex (S1) (P<0.05 with an effect size of 4.34). Likewise, PL decreased significantly in the patient group following application of a-tDCS to both the M1 and dorsolateral prefrontal cortex (DLPFC). The average decrease in visual analogue score was 14.9% and 19.3% after applying a-tDCS on the M1 and DLPFC. Moreover, meta-analysis showed that in all subgroups (except a-tDCS of S1) active a-tDCS and sham stimulation produced significant differences. This review provides evidence for the effectiveness of a-tDCS in increasing STh/PTh in healthy group and decreasing PL in patients. However, due to small sample sizes in the included studies, our results should be interpreted cautiously. Given the level of blinding did not considered in inclusion criteria, the result of current study should be interpreted with caution. Site of stimulation should have a differential effect over pain relief. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  12. Effects of prefrontal anodal transcranial direct current stimulation on working-memory and reaction time.

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    Verissimo, Ines S; Barradas, Isabel M; Santos, Tiago T; Miranda, Pedro C; Ferreira, Hugo A

    2016-08-01

    Transcranial direct current stimulation (tDCS) has proven to be a useful tool in the scientific research community, particularly for clinical investigation purposes. Neuroimaging studies indicate that there is a connection between the prefrontal cortex (PFC) and working memory (WM), as well as between the primary motor cortex and reaction time (RT). Thus, our goal was to evaluate the effect of anodal stimulation of the PFC, with respect to WM and RT. We tested 20 healthy subjects randomized into two groups - half received active stimulation and the other half sham stimulation. Participants underwent two stimulation sessions of 10 minutes each, separated by a 10-minute interval for rest. The task was performed during the stimulation periods, and consisted in the display of a list of words for the subject to read and memorize. Afterwards, a new list was shown and the subject was asked to to press a key when a repeated word appeared. A current of 1 mA was delivered via a foc.us gamer headset. After both stimulations, the participants answered an Adverse Effects Questionnaire. Statistical tests were performed to compare the accuracy, error rate, and reaction time values for active vs. sham and first vs. second stimulations. The results obtained led us to infer that there were no significant improvements in the performance of the active group in comparison with the sham group, in terms of WM and overall RT values. However, RT data analysis indicated that active simulation subjects showed significantly lower values when compared to the sham group, only for the first stimulation period. Due to emerging technological advances, the videogame industry has started to invest in the commercialization of products that promise to enhance neural functions and, thus, improve gamers' performance. The results obtained provide evidence of the importance of testing such commercial devices. The scientific community should have an active role in the validation of these claims.

  13. Effects of anodal transcranial direct current stimulation over lower limb primary motor cortex on motor learning in healthy individuals.

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    Foerster, Águida; Dutta, Anirban; Kuo, Min-Fang; Paulus, Walter; Nitsche, Michael A

    2018-02-14

    Transcranial direct current stimulation (tDCS) is a neuromodulatory technique which alters motor functions in healthy humans and in neurological patients. Most studies so far investigated the effects of tDCS on mechanisms underlying improvements in upper limb performance. To investigate the effect of anodal tDCS over the lower limb motor cortex (M1) on lower limb motor learning in healthy volunteers, we conducted a randomized, single-blind and sham-controlled study. Thirty-three (25.81 ± 3.85, 14 female) volunteers were included, and received anodal or sham tDCS over the left M1 (M1-tDCS); 0.0625 mA/cm 2 anodal tDCS was applied for 15 min during performance of a visuo-motor task (VMT) with the right leg. Motor learning was monitored for performance speed and accuracy based on electromyographic recordings. We also investigated the influence of electrode size and baseline responsivity to transcranial magnetic stimulation (TMS) on the stimulation effects. Relative to baseline measures, only M1-tDCS applied with small electrodes and in volunteers with high baseline sensitivity to TMS significantly improved VMT performance. The computational analysis showed that the small anode was more specific to the targeted leg motor cortex volume when compared to the large anode. We conclude that anodal M1-tDCS modulates VMT performance in healthy subjects. As these effects critically depend on sensitivity to TMS and electrode size, future studies should investigate the effects of intensified tDCS and/or model-based different electrode positions in low-sensitivity TMS individuals. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  14. Differential modulation of corticospinal excitability by different current densities of anodal transcranial direct current stimulation.

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    Andisheh Bastani

    Full Text Available BACKGROUND: Novel non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS have been developed in recent years. TDCS-induced corticospinal excitability changes depend on two important factors current intensity and stimulation duration. Despite clinical success with existing tDCS parameters, optimal protocols are still not entirely set. OBJECTIVE/HYPOTHESIS: The current study aimed to investigate the effects of four different anodal tDCS (a-tDCS current densities on corticospinal excitability. METHODS: Four current intensities of 0.3, 0.7, 1.4 and 2 mA resulting in current densities (CDs of 0.013, 0.029, 0.058 and 0.083 mA/cm(2 were applied on twelve right-handed (mean age 34.5±10.32 yrs healthy individuals in different sessions at least 48 hours apart. a-tDCS was applied continuously for 10 minute, with constant active and reference electrode sizes of 24 and 35 cm(2 respectively. The corticospinal excitability of the extensor carpi radialis muscle (ECR was measured before and immediately after the intervention and at 10, 20 and 30 minutes thereafter. RESULTS: Post hoc comparisons showed significant differences in corticospinal excitability changes for CDs of 0.013 mA/cm(2 and 0.029 mA/cm(2 (P = 0.003. There were no significant differences between excitability changes for the 0.013 mA/cm(2 and 0.058 mA/cm(2 (P = 0.080 or 0.013 mA/cm(2 and 0.083 mA/cm(2 (P = 0.484 conditions. CONCLUSION: This study found that a-tDCS with a current density of 0.013 mA/cm(2 induces significantly larger corticospinal excitability changes than CDs of 0.029 mA/cm(2. The implication is that might help to avoid applying unwanted amount of current to the cortical areas.

  15. Assessment of anodal and cathodal transcranial direct current stimulation (tDCS) on MMN-indexed auditory sensory processing.

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

    2016-06-01

    Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation which uses a very weak constant current to temporarily excite (anodal stimulation) or inhibit (cathodal stimulation) activity in the brain area of interest via small electrodes placed on the scalp. Currently, tDCS of the frontal cortex is being used as a tool to investigate cognition in healthy controls and to improve symptoms in neurological and psychiatric patients. tDCS has been found to facilitate cognitive performance on measures of attention, memory, and frontal-executive functions. Recently, a short session of anodal tDCS over the temporal lobe has been shown to increase auditory sensory processing as indexed by the Mismatch Negativity (MMN) event-related potential (ERP). This preliminary pilot study examined the separate and interacting effects of both anodal and cathodal tDCS on MMN-indexed auditory pitch discrimination. In a randomized, double blind design, the MMN was assessed before (baseline) and after tDCS (2mA, 20min) in 2 separate sessions, one involving 'sham' stimulation (the device is turned off), followed by anodal stimulation (to temporarily excite cortical activity locally), and one involving cathodal stimulation (to temporarily decrease cortical activity locally), followed by anodal stimulation. Results demonstrated that anodal tDCS over the temporal cortex increased MMN-indexed auditory detection of pitch deviance, and while cathodal tDCS decreased auditory discrimination in baseline-stratified groups, subsequent anodal stimulation did not significantly alter MMN amplitudes. These findings strengthen the position that tDCS effects on cognition extend to the neural processing of sensory input and raise the possibility that this neuromodulatory technique may be useful for investigating sensory processing deficits in clinical populations. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Does the Longer Application of Anodal-Transcranial Direct Current Stimulation Increase Corticomotor Excitability Further? A Pilot Study

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    Shapour Jaberzadeh

    2012-09-01

    Full Text Available Introduction: Anodal transcranial direct current stimulation (a-tDCS of the primary motor cortex (M1 has been shown to be effective in increasing corticomotor excitability.Methods: We investigated whether longer applications of a-tDCS coincide with greater increases in corticomotor excitability compared to shorter application of a-tDCS. Ten right-handed healthy participants received one session of a-tDCS(1mA current with shorter (10 min and longer (10+10 min stimulation durationsapplied to the left M1 of extensor carpi radialis muscle (ECR. Corticomotorexcitability following application of a-tDCS was assessed at rest with transcranial magnetic stimulation (TMS elicited motor evoked otentials (MEP and compared with baseline data for each participant.Results: MEP amplitudes were increased following 10 min of a-tDCS by 67%(p = 0.001 with a further increase (32% after the second 10 min of a-tDCS (p = 0.005. MEP amplitudes remained elevated at 15 min post stimulation compared to baseline values by 65% (p = 0.02.Discussion: The results demonstrate that longer application of a-tDCS within the recommended safety limits, increases corticomotor excitability with after effects of up to 15 minutes post stimulation.

  17. Does the Longer Application of Anodal-Transcranial Direct Current Stimulation Increase Corticomotor Excitability Further? A Pilot Study

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    Shapour Jaberzadeh

    2012-08-01

    Full Text Available Introduction: Anodal transcranial direct current stimulation (a-tDCS of the primary motor cortex (M1 has been shown to be effective in increasing corticomotor excitability.  Methods: We investigated whether longer applications of a-tDCS coincide with greater increases in corticomotor excitability compared to shorter application of a-tDCS. Ten right-handed healthy participants received one session of a-tDCS (1mA current with shorter (10 min and longer (10+10 min stimulation durations applied to the left M1 of extensor carpi radialis muscle (ECR. Corticomotor excitability following application of a-tDCS was assessed at rest with transcranial magnetic stimulation (TMS elicited motor evoked potentials (MEP and compared with baseline data for each participant.  Results: MEP amplitudes were increased following 10 min of a-tDCS by 67% (p = 0.001 with a further increase (32% after the second 10 min of a-tDCS (p = 0.005. MEP amplitudes remained elevated at 15 min post stimulation compared to baseline values by 65% (p = 0.02.  Discussion: The results demonstrate that longer application of a-tDCS within the recommended safety limits, increases corticomotor excitability with after effects of up to 15 minutes post stimulation.

  18. The effect of anodal transcranial direct current stimulation over the primary motor or somatosensory cortices on somatosensory evoked magnetic fields.

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    Sugawara, Kazuhiro; Onishi, Hideaki; Yamashiro, Koya; Kojima, Sho; Miyaguchi, Shota; Kirimoto, Hikari; Tsubaki, Atsuhiro; Tamaki, Hiroyuki; Shirozu, Hiroshi; Kameyama, Shigeki

    2015-01-01

    The purpose of this study was to investigate the effect of anodal transcranial direct-current stimulation (tDCS) applied over the primary motor (M1) or the primary somatosensory (S1) cortices on somatosensory evoked magnetic fields (SEFs) following median nerve stimulation. Anodal tDCS was applied for 15min on the left motor or somatosensory cortices at 1mA. SEFs were recorded following right median nerve stimulation using a magnetoencephalography (MEG) system before and after the application of tDCS. SEFs was measured and compared before and after tDCS was applied over M1 or S1. The source strengths for the P35m and P60m increased after tDCS was applied over M1 and that for the P60m increased after tDCS was applied over S1. The mean equivalent current dipole (ECD) location for the P35m was located significantly anterior to that of the N20m, but only during post 1 (10-20min after tDCS was applied over M1). Our results indicated that the anodal tDCS applied over M1 affected the P35m and P60m sources on SEF components, while that applied over S1 influenced the P60m source. We demonstrated anodal tDCS applied over M1 or S1 can modulate somatosensory processing and components of SEFs, confirming the hypothesis for locally distinct generators of the P35m and P60m sources. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  19. Transcranial direct current stimulation facilitates cognitive multi-task performance differentially depending on anode location and subtask.

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    Melissa eScheldrup

    2014-09-01

    Full Text Available There is a need to facilitate acquisition of real world cognitive multi-tasks that require long periods of training (e.g., air traffic control, intelligence analysis, medicine. Non-invasive brain stimulation – specifically transcranial Direct Current Stimulation (tDCS – has promise as a method to speed multi-task training. We hypothesized that during acquisition of the complex multi-task Space Fortress, subtasks that require focused attention on ship control would benefit from tDCS aimed at the dorsal attention network while subtasks that require redirection of attention would benefit from tDCS aimed at the right hemisphere ventral attention network. We compared effects of 30 min prefrontal and parietal stimulation to right and left hemispheres on subtask performance during the first 45 min of training. The strongest effects both overall and for ship flying (control and velocity subtasks were seen with a right parietal (C4 to left shoulder montage, shown by modeling to induce an electric field that includes nodes in both dorsal and ventral attention networks. This is consistent with the re-orienting hypothesis that the ventral attention network is activated along with the dorsal attention network if a new, task-relevant event occurs while visuospatial attention is focused (Corbetta et al., 2008. No effects were seen with anodes over sites that stimulated only dorsal (C3 or only ventral (F10 attention networks. The speed subtask (update memory for symbols benefited from an F9 anode over left prefrontal cortex. These results argue for development of tDCS as a training aid in real world settings where multi-tasking is critical.

  20. Influence of anodal transcranial direct current stimulation (tDCS over the right angular gyrus on brain activity during rest.

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    Benjamin Clemens

    Full Text Available Although numerous studies examined resting-state networks (RSN in the human brain, so far little is known about how activity within RSN might be modulated by non-invasive brain stimulation applied over parietal cortex. Investigating changes in RSN in response to parietal cortex stimulation might tell us more about how non-invasive techniques such as transcranial direct current stimulation (tDCS modulate intrinsic brain activity, and further elaborate our understanding of how the resting brain responds to external stimulation. Here we examined how activity within the canonical RSN changed in response to anodal tDCS applied over the right angular gyrus (AG. We hypothesized that changes in resting-state activity can be induced by a single tDCS session and detected with functional magnetic resonance imaging (fMRI. Significant differences between two fMRI sessions (pre-tDCS and post-tDCS were found in several RSN, including the cerebellar, medial visual, sensorimotor, right frontoparietal, and executive control RSN as well as the default mode and the task positive network. The present results revealed decreased and increased RSN activity following tDCS. Decreased RSN activity following tDCS was found in bilateral primary and secondary visual areas, and in the right putamen. Increased RSN activity following tDCS was widely distributed across the brain, covering thalamic, frontal, parietal and occipital regions. From these exploratory results we conclude that a single session of anodal tDCS over the right AG is sufficient to induce large-scale changes in resting-state activity. These changes were localized in sensory and cognitive areas, covering regions close to and distant from the stimulation site.

  1. Repeated anodal transcranial direct current stimulation induces neural plasticity-associated gene expression in the rat cortex and hippocampus.

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    Kim, Min Sun; Koo, Ho; Han, Sang Who; Paulus, Walter; Nitsche, Michael A; Kim, Yun-Hee; Yoon, Jin A; Shin, Yong-Il

    2017-01-01

    Anodal transcranial direct current stimulation (A-tDCS) induces a long-lasting increase in cortical excitability that can increase gene transcription in the brain. The purpose of this study was to evaluate the expression of genes related to activity-dependent neuronal plasticity in the sensorimotor cortex and hippocampus of young Sprague-Dawley rats following A-tDCS. We applied A-tDCS over the right sensorimotor cortex epicranially with a circular electrode (3 mm diameter) at 250 μA for 20 min per day for 7 consecutive days. Levels of mRNA for brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), synapsin I, Ca2+/calmodulin-dependent protein kinase II (CaMKII), activity-regulated cytoskeleton-associated protein (Arc), and c-Fos were analyzed using SYBR Green quantitative real-time polymerase chain reaction (PCR). We found that 7 days of unilateral A-tDCS resulted in significant increases in transcription of all plasticity-related genes tested in the ipsilateral cortex. Daily A-tDCS also resulted in a significant increase in c-Fos mRNA in the ipsilateral hippocampus. These results indicate that altered expression of plasticity-associated genes in the cortex and hippocampus is a molecular substrate of A-tDCS-induced neural plasticity.

  2. No effects of anodal transcranial direct stimulation on language abilities in early rehabilitation of post-stroke aphasic patients.

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    Polanowska, K E; Leśniak, M; Seniów, J B; Członkowska, A

    2013-01-01

    Recent research suggests that an increased level of stroke-affected left hemisphere cortical (especially frontal) excitability is associated with better language improvement in aphasic patients. Anodal transcranial direct current stimulation (A-tDCS), increasing cortical activity, may facilitate perilesional left hemisphere recruitment to subserve language processing and enhance effects of behavioural therapy. The aim of the study (randomized, double-blind, sham-controlled) was to evaluate the effectiveness of repeated A-tDCS over Broca area as a strategy to enhance aphasia recovery during early post-stroke rehabilitation. Thirty-seven participants with moderate or severe aphasia were randomized to receive 15 consecutive daily sessions of A-tDCS (1 mA, 10 min; experimental group, n = 18) or sham stimulation (1 mA, 25 s; control group, n = 19) followed by language therapy. Effects of tDCS were assessed using the Boston Diagnostic Aphasia Examination, performed before and after the rehabilitation, and three months later. The results did not confirm a positive impact of repeated A-tDCS, preceding language therapy, on language abilities in our patients. Although both groups improved after the therapy, there were no statistically significant differences between groups in either short-term or long-term tDCS effects. Effect sizes for the experimental group, at post-treatment and the 3-month follow-up, were slightly higher than in controls but insufficient to infer any beneficial influence of the applied intervention. The findings do not support A-tDCS functional benefits during early rehabilitation of post-stroke aphasia. Further research is needed to explore the effectiveness of this kind of neuromodulation.

  3. Impact of Anodal and Cathodal Transcranial Direct Current Stimulation over the Left Dorsolateral Prefrontal Cortex during Attention Bias Modification: An Eye-Tracking Study.

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    Alexandre Heeren

    Full Text Available People with anxiety disorders show an attentional bias for threat (AB, and Attention Bias Modification (ABM procedures have been found to reduce this bias. However, the underlying processes accounting for this effect remain poorly understood. One explanation suggests that ABM requires the modification of attention control, driven by the recruitment of the dorsolateral prefrontal cortex (DLPFC. In the present double-blind study, we examined whether modifying left DLPFC activation influences the effect of ABM on AB. We used transcranial direct current stimulation (tDCS to directly modulate cortical excitability of the left DLPFC during an ABM procedure designed to reduce AB to threat. Anodal tDCS increases excitability, whereas cathodal tDCS decreases it. We randomly assigned highly trait-anxious individuals to one of three conditions: 1 ABM combined with cathodal tDCS, 2 ABM combined with anodal tDCS, or 3 ABM combined with sham tDCS. We assessed the effects of these manipulations on both reaction times and eye-movements on a task indexing AB. Results indicate that combining ABM and anodal tDCS over the left DLPFC reduces the total duration that participants' gaze remains fixated on threat, as assessed using eye-tracking measurement. However, in contrast to previous studies, there were no changes in AB from baseline to post-training for participants that received ABM without tDCS. As the tendency to maintain attention to threat is known to play an important role in the maintenance of anxiety, the present findings suggest that anodal tDCS over the left DLPFC may be considered as a promising tool to reduce the maintenance of gaze to threat. Implications for future translational research combining ABM and tDCS are discussed.

  4. Anodal transcranial direct current stimulation of the right dorsolateral prefrontal cortex enhances memory-guided responses in a visuospatial working memory task.

    Science.gov (United States)

    Giglia, Giuseppe; Brighina, Filippo; Rizzo, Silvia; Puma, Angela; Indovino, Serena; Maccora, Simona; Baschi, Roberta; Cosentino, Giuseppe; Fierro, Brigida

    2014-01-01

    Several studies have shown that transcranial direct current stimulation (tDCS) is able to enhance performances on verbal and visual working memory (WM) tasks. Available evidence points to the right dorsolateral prefrontal cortex (DLPFC) as a critical area in visual WM, but to date direct comparisons of the effects obtained by stimulating the left versus the right DLPFC in the same subject are lacking. Our aim was to determine whether tDCS over the right DLPFC can differently affect performance as compared with left DLPFC stimulation. Ten healthy subjects performed a memory-guided visuospatial task in three conditions: baseline, during anodal stimulation applied over the right and during anodal stimulation applied over the left DLPFC. All the subjects also underwent a sham stimulation as control. Our results show that only active stimulation over the right DLPFC is able to increase performance when compared to the other conditions. Our findings confirm the crucial role played by the right DLPFC in spatial WM tasks.

  5. Effects of anodal transcranial direct current stimulation (tDCS) on behavioral and spatial memory during the early stage of traumatic brain injury in the rats.

    Science.gov (United States)

    Yoon, Kyung Jae; Lee, Yong-Taek; Chae, Seoung Wan; Park, Chae Ri; Kim, Dae Yul

    2016-03-15

    Transcranial direct current stimulation (tDCS) is a noninvasive technique to modulate the neural membrane potential. Its effects in the early stage of traumatic brain injury (TBI) have rarely been investigated. This study assessed the effects of anodal tDCS on behavioral and spatial memory in a rat model of traumatic brain injury. Thirty six rats underwent lateral fluid percussion and were then randomly assigned to one of three groups: control (n=12), five-day tDCS over peri-lesional cortex at one (1W, n=12), or two (2W, n=12) weeks post-injury. The Barnes maze (BM) and Rotarod (RR) tests were evaluated in a blind manner on day 1, week 3 and week 5 post-injury. After three weeks, both the 1W and 2W groups showed significant improvements in the BM ratio (Pearly phase after TBI when it is delivered two weeks post-injury. Earlier stimulation (one week post-injury) improves spatial memory only. However, the beneficial effects did not persist after cessation of the anodal stimulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Modulating the resting-state functional connectivity patterns of language processing areas in the human brain with anodal transcranial direct current stimulation applied over the Broca's area.

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    Cao, Jianwei; Liu, Hanli; Alexandrakis, George

    2018-04-01

    Cortical circuit reorganization induced by anodal transcranial direct current stimulation (tDCS) over the Broca's area of the dominant language hemisphere in 13 healthy adults was quantified by functional near-infrared spectroscopy (fNIRS). Transient cortical reorganization patterns in steady-state functional connectivity (seed-based and graph theory analysis) and temporal functional connectivity (sliding window correlation analysis) were recorded before, during, and after applying high current tDCS (1 mA, 8 min). fNIRS connectivity mapping showed that tDCS induced significantly ([Formula: see text]) increased functional connectivity between Broca's area and its neighboring cortical regions while it simultaneously decreased the connectivity to remote cortical regions. Furthermore, the anodal stimulation caused significant increases to the functional connectivity variability (FCV) of remote cortical regions related to language processing. In addition to the high current tDCS, low current tDCS (0.5 mA, 2 min 40 s) was also applied to test whether the transient effects of lower stimulation current could qualitatively predict cortical connectivity alterations induced by the higher currents. Interestingly, low current tDCS could qualitatively predict the increase in clustering coefficient and FCV but not the enhancement of local connectivity. Our findings indicate the possibility of combining future studies fNIRS with tDCS at lower currents to help guide therapeutic interventions.

  7. Transcranial Direct Current Stimulation Improves Audioverbal Memory in Stroke Patients.

    Science.gov (United States)

    Kazuta, Toshinari; Takeda, Kotaro; Osu, Rieko; Tanaka, Satoshi; Oishi, Ayako; Kondo, Kunitsugu; Liu, Meigen

    2017-08-01

    The aim of this study was to investigate whether anodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance in stroke patients. Twelve stroke patients with audioverbal memory impairment participated in a single-masked, crossover, and sham-controlled experiment. The anodal or sham transcranial direct current stimulation was applied during the Rey Auditory Verbal Learning Test, which evaluates the ability to recall a list of 15 heard words over five trials. The number of correctly recalled words was compared between the anodal and sham conditions and the influence of transcranial direct current stimulation on serial position effect of the 15 words was also examined. The increase in the number of correctly recalled words from the first to the fifth trial was significantly greater in the anodal condition than in the sham condition (P patients.

  8. 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

  9. Anodal transcranial direct current stimulation of the right dorsolateral prefrontal cortex enhances memory-guided responses in a visuospatial working memory task

    OpenAIRE

    Giglia, Giuseppe; Brighina, Filippo; Rizzo, Silvia; Puma, Angela; Indovino, Serena; Maccora, Simona; Baschi, Roberta; Cosentino, Giuseppe; Fierro, Brigida

    2014-01-01

    Several studies have shown that transcranial direct current stimulation (tDCS) is able to enhance performances on verbal and visual working memory (WM) tasks. Available evidence points to the right dorsolateral prefrontal cortex (DLPFC) as a critical area in visual WM, but to date direct comparisons of the effects obtained by stimulating the left versus the right DLPFC in the same subject are lacking.

  10. Effects of High-Definition Anodal Transcranial Direct Current Stimulation Applied Simultaneously to Both Primary Motor Cortices on Bimanual Sensorimotor Performance

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    Nils H. Pixa

    2017-07-01

    Full Text Available Many daily activities, such as tying one’s shoe laces, opening a jar of jam or performing a free throw in basketball, require the skillful coordinated use of both hands. Even though the non-invasive method of transcranial direct current stimulation (tDCS has been repeatedly shown to improve unimanual motor performance, little is known about its effects on bimanual motor performance. More knowledge about how tDCS may improve bimanual behavior would be relevant to motor recovery, e.g., in persons with bilateral impairment of hand function. We therefore examined the impact of high-definition anodal tDCS (HD-atDCS on the performance of a bimanual sequential sensorimotor task. Thirty-two volunteers (age M = 24.25; SD = 2.75; 14 females participated in this double-blind study and performed sport stacking in six experimental sessions. In sport stacking, 12 specially designed cups must be stacked (stacked up and dismantled (stacked down in predefined patterns as fast as possible. During a pretest, posttest and follow-up test, two sport stacking formations (3-6-3 stack and 1-10-1 stack were performed. Between the pretest and posttest, all participants were trained in sport stacking with concurrent brain stimulation for three consecutive days. The experimental group (STIM-M1 received HD-atDCS over both primary motor cortices (M1, while the control group received a sham stimulation (SHAM. Three-way analysis of variance (ANOVA revealed a significant main effect of TIME and a significant interaction of TIME × GROUP. No significant effects were found for GROUP, nor for the three-way interaction of TIME × GROUP × FORMATION. Further two-way ANOVAs showed a significant main effect of TIME and a non-significant main effect for GROUP in both sport stacking formations. A significant interaction between TIME × GROUP was found only for the 3-6-3 formation, indicating superior performance gains for the experimental group (STIM-M1. To account and control for

  11. Effects of High-Definition Anodal Transcranial Direct Current Stimulation Applied Simultaneously to Both Primary Motor Cortices on Bimanual Sensorimotor Performance

    Science.gov (United States)

    Pixa, Nils H.; Steinberg, Fabian; Doppelmayr, Michael

    2017-01-01

    Many daily activities, such as tying one’s shoe laces, opening a jar of jam or performing a free throw in basketball, require the skillful coordinated use of both hands. Even though the non-invasive method of transcranial direct current stimulation (tDCS) has been repeatedly shown to improve unimanual motor performance, little is known about its effects on bimanual motor performance. More knowledge about how tDCS may improve bimanual behavior would be relevant to motor recovery, e.g., in persons with bilateral impairment of hand function. We therefore examined the impact of high-definition anodal tDCS (HD-atDCS) on the performance of a bimanual sequential sensorimotor task. Thirty-two volunteers (age M = 24.25; SD = 2.75; 14 females) participated in this double-blind study and performed sport stacking in six experimental sessions. In sport stacking, 12 specially designed cups must be stacked (stacked up) and dismantled (stacked down) in predefined patterns as fast as possible. During a pretest, posttest and follow-up test, two sport stacking formations (3-6-3 stack and 1-10-1 stack) were performed. Between the pretest and posttest, all participants were trained in sport stacking with concurrent brain stimulation for three consecutive days. The experimental group (STIM-M1) received HD-atDCS over both primary motor cortices (M1), while the control group received a sham stimulation (SHAM). Three-way analysis of variance (ANOVA) revealed a significant main effect of TIME and a significant interaction of TIME × GROUP. No significant effects were found for GROUP, nor for the three-way interaction of TIME × GROUP × FORMATION. Further two-way ANOVAs showed a significant main effect of TIME and a non-significant main effect for GROUP in both sport stacking formations. A significant interaction between TIME × GROUP was found only for the 3-6-3 formation, indicating superior performance gains for the experimental group (STIM-M1). To account and control for baseline

  12. Anodal Transcranial Direct Current Stimulation Shows Minimal, Measure-Specific Effects on Dynamic Postural Control in Young and Older Adults: A Double Blind, Sham-Controlled Study.

    Science.gov (United States)

    Craig, Chesney E; Doumas, Michail

    2017-01-01

    We investigated whether stimulating the cerebellum and primary motor cortex (M1) using transcranial direct current stimulation (tDCS) could affect postural control in young and older adults. tDCS was employed using a double-blind, sham-controlled design, in which young (aged 18-35) and older adults (aged 65+) were assessed over three sessions, one for each stimulatory condition-M1, cerebellar and sham. The effect of tDCS on postural control was assessed using a sway-referencing paradigm, which induced platform rotations in proportion to the participant's body sway, thus assessing sensory reweighting processes. Task difficulty was manipulated so that young adults experienced a support surface that was twice as compliant as that of older adults, in order to minimise baseline age differences in postural sway. Effects of tDCS on postural control were assessed during, immediately after and 30 minutes after tDCS. Additionally, the effect of tDCS on corticospinal excitability was measured by evaluating motor evoked potentials using transcranial magnetic stimulation immediately after and 30 minutes after tDCS. Minimal effects of tDCS on postural control were found in the eyes open condition only, and this was dependent on the measure assessed and age group. For young adults, stimulation had only offline effects, as cerebellar stimulation showed higher mean power frequency (MPF) of sway 30 minutes after stimulation. For older adults, both stimulation conditions delayed the increase in sway amplitude witnessed between blocks one and two until stimulation was no longer active. In conclusion, despite tDCS' growing popularity, we would caution researchers to consider carefully the type of measures assessed and the groups targeted in tDCS studies of postural control.

  13. Brain transcranial direct current stimulation modulates motor excitability in mice.

    Science.gov (United States)

    Cambiaghi, Marco; Velikova, Svetla; Gonzalez-Rosa, Javier J; Cursi, Marco; Comi, Giancarlo; Leocani, Letizia

    2010-02-01

    Shortly after the application of weak transcranial direct current stimulation (tDCS) to the animal and human brain, changes in corticospinal excitability, which mainly depend on polarity, duration and current density of the stimulation protocol, have been reported. In humans, anodal tDCS has been reported to enhance motor-evoked potentials (MEPs) elicited by transcranial brain stimulation while cathodal tDCS has been shown to decrease them. Here we investigated the effects produced by tDCS on mice motor cortex. MEPs evoked by transcranial electric stimulation were recorded from forelimbs of 12 C57BL/6 mice, under sevofluorane anaesthesia, before and after (0, 5 and 10 min) anodal and cathodal tDCS (tDCS duration 10 min). With respect to sham condition stimulation (anaesthesia), MEP size was significantly increased immediately after anodal tDCS, and was reduced after cathodal tDCS (approximately 20% vs. sham). Both effects declined towards basal levels in the following 10 min. Although the site and mechanisms of action of tDCS need to be more clearly identified, the directionality of effects of tDCS on mice MEPs is consistent with previous findings in humans. The feasibility of tDCS in mice suggests the potential applicability of this technique to assess the potential therapeutic options of brain polarization in animal models of neurological and neuropsychiatric diseases.

  14. Effects of transcranial direct current stimulation on episodic memory related to emotional visual stimuli

    OpenAIRE

    Penolazzi, Barbara; Di Domenico, Alberto; Marzoli, Daniele; Mammarella, Nicola; Fairfield, Beth; Franciotti, Raffaella; Brancucci, Alfredo; Tommasi, Luca

    2010-01-01

    The present study investigated emotional memory following bilateral transcranial electrical stimulation (direct current of 1 mA, for 20 minutes) over fronto-temporal cortical areas of healthy participants during the encoding of images that differed in affective arousal and valence. The main result was a significant interaction between the side of anodal stimulation and image emotional valence. Specifically, right anodal/left cathodal stimulation selectively facilitated the recall of pleasant ...

  15. Enhancing the mirror illusion with transcranial direct current stimulation.

    Science.gov (United States)

    Jax, Steven A; Rosa-Leyra, Diana L; Coslett, H Branch

    2015-05-01

    Visual feedback has a strong impact on upper-extremity movement production. One compelling example of this phenomena is the mirror illusion (MI), which has been used as a treatment for post-stroke movement deficits (mirror therapy). Previous research indicates that the MI increases primary motor cortex excitability, and this change in excitability is strongly correlated with the mirror's effects on behavioral performance of neurologically-intact controls. Based on evidence that primary motor cortex excitability can also be increased using transcranial direct current stimulation (tDCS), we tested whether bilateral tDCS to the primary motor cortices (anode right-cathode left and anode left-cathode right) would modify the MI. We measured the MI using a previously-developed task in which participants make reaching movements with the unseen arm behind a mirror while viewing the reflection of the other arm. When an offset in the positions of the two limbs relative to the mirror is introduced, reaching errors of the unseen arm are biased by the reflected arm's position. We found that active tDCS in the anode right-cathode left montage increased the magnitude of the MI relative to sham tDCS and anode left-cathode right tDCS. We take these data as a promising indication that tDCS could improve the effect of mirror therapy in patients with hemiparesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Determinants of the electric field during transcranial direct current stimulation

    DEFF Research Database (Denmark)

    Opitz, Alexander; Paulus, Walter; Will, Susanne

    2015-01-01

    Transcranial direct current stimulation (tDCS) causes a complex spatial distribution of the electric current flow in the head which hampers the accurate localization of the stimulated brain areas. In this study we show how various anatomical features systematically shape the electric field...... over the motor cortex in small steps to examine the resulting changes of the electric field distribution in the underlying cortex. We examined the effect of skull thickness and composition on the passing currents showing that thinner skull regions lead to higher electric field strengths. This effect...... fluid and the skull, the gyral depth and the distance to the anode and cathode. These factors account for up to 50% of the spatial variation of the electric field strength. Further, we demonstrate that individual anatomical factors can lead to stimulation "hotspots" which are partly resistant...

  17. Transcranial direct current stimulation as a treatment for auditory hallucinations.

    Directory of Open Access Journals (Sweden)

    Sanne eKoops

    2015-03-01

    Full Text Available Auditory hallucinations (AH are a symptom of several psychiatric disorders, such as schizophrenia. In a significant minority of patients, AH are resistant to antipsychotic medication. Alternative treatment options for this medication-resistant group are scarce and most of them focus on coping with the hallucinations. Finding an alternative treatment that can diminish AH is of great importance.Transcranial direct current stimulation (tDCS is a safe and non-invasive technique that is able to directly influence cortical excitability through the application of very low electric currents. A 1-2 mA direct current is applied between two surface electrodes, one serving as the anode and the other as the cathode. Cortical excitability is increased in the vicinity of the anode and reduced near the cathode. The technique, which has only a few transient side effects and is cheap and portable, is increasingly explored as a treatment for neurological and psychiatric symptoms. It has shown efficacy on symptoms of depression, bipolar disorder, schizophrenia, Alzheimer’s disease, Parkinson’s disease, epilepsy and stroke. However, the application of tDCS as a treatment for AH is relatively new. This article provides an overview of the current knowledge in this field and provides guidelines for future research.

  18. Transcranial Direct Current Stimulation and behavioral models of smoking addiction

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    Paige eFraser

    2012-08-01

    Full Text Available While few studies have applied transcranial direct current stimulation (tDCS to smoking addiction, existing work suggests that the intervention holds promise for altering the complex system by which environmental cues interact with cravings to drive behavior. Imaging and repetitive transcranial magnetic stimulation (rTMS studies suggest that increased dorsolateral prefrontal cortex (DLPFC activation and integrity may be associated with increased resistance to smoking cues. Anodal tDCS of the DLPFC, believed to boost activation, reduces cravings in response to these cues. The finding that noninvasive stimulation modifies cue induced cravings has profound implications for understanding the processes underlying addiction and relapse. TDCS can also be applied to probe mechanisms underlying and supporting nicotine addiction, as was done in a pharmacologic study that applied nicotine, tDCS, and TMS paired associative stimulation to find that stopping nicotine after chronic use induces a reduction in plasticity, causing difficulty in breaking free from association between cues and cravings. This mini-review will place studies that apply tDCS to smokers in the context of research involving the neural substrates of nicotine addiction.

  19. 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...... amplitudes appear to be sensitive to training with the tongue using TDS; however anodal tDCS does not have an impact on training-evoked neuroplasticity of tongue corticomotor pathways....

  20. The effect of bilateral transcranial direct current stimulation on early auditory processing in schizophrenia: a preliminary study.

    Science.gov (United States)

    Dunn, Walter; Rassovsky, Yuri; Wynn, Jonathan; Wu, Allan D; Iacoboni, Marco; Hellemann, Gerhard; Green, Michael F

    2017-09-01

    Transcranial direct current stimulation (tDCS) was applied bilaterally over the auditory cortex in 12 schizophrenia patients to modulate early auditory processing. Performance on a tone discrimination task (tone-matching task-TMT) and auditory mismatch negativity were assessed after counterbalanced anodal, cathodal, and sham tDCS. Cathodal stimulation improved TMT performance (p stimulation condition by negative symptom interaction in which greater negative symptoms were associated with a better TMT performance after anodal tDCS.

  1. Animal models of transcranial direct current stimulation: Methods and mechanisms.

    Science.gov (United States)

    Jackson, Mark P; Rahman, Asif; Lafon, Belen; Kronberg, Gregory; Ling, Doris; Parra, Lucas C; Bikson, Marom

    2016-11-01

    The objective of this review is to summarize the contribution of animal research using direct current stimulation (DCS) to our understanding of the physiological effects of transcranial direct current stimulation (tDCS). We comprehensively address experimental methodology in animal studies, broadly classified as: (1) transcranial stimulation; (2) direct cortical stimulation in vivo and (3) in vitro models. In each case advantages and disadvantages for translational research are discussed including dose translation and the overarching "quasi-uniform" assumption, which underpins translational relevance in all animal models of tDCS. Terminology such as anode, cathode, inward current, outward current, current density, electric field, and uniform are defined. Though we put key animal experiments spanning decades in perspective, our goal is not simply an exhaustive cataloging of relevant animal studies, but rather to put them in context of ongoing efforts to improve tDCS. Cellular targets, including excitatory neuronal somas, dendrites, axons, interneurons, glial cells, and endothelial cells are considered. We emphasize neurons are always depolarized and hyperpolarized such that effects of DCS on neuronal excitability can only be evaluated within subcellular regions of the neuron. Findings from animal studies on the effects of DCS on plasticity (LTP/LTD) and network oscillations are reviewed extensively. Any endogenous phenomena dependent on membrane potential changes are, in theory, susceptible to modulation by DCS. The relevance of morphological changes (galvanotropy) to tDCS is also considered, as we suggest microscopic migration of axon terminals or dendritic spines may be relevant during tDCS. A majority of clinical studies using tDCS employ a simplistic dose strategy where excitability is singularly increased or decreased under the anode and cathode, respectively. We discuss how this strategy, itself based on classic animal studies, cannot account for the

  2. Slow-oscillatory transcranial direct current stimulation can induce bidirectional shifts in motor cortical excitability in awake humans

    DEFF Research Database (Denmark)

    Groppa, S; Bergmann, T O; Siems, C

    2010-01-01

    Constant transcranial direct stimulation (c-tDCS) of the primary motor hand area (M1(HAND)) can induce bidirectional shifts in motor cortical excitability depending on the polarity of tDCS. Recently, anodal slow oscillation stimulation at a frequency of 0.75 Hz has been shown to augment intrinsic...

  3. Mild cognitive impairment in Parkinson's disease is improved by transcranial direct current stimulation combined with physical therapy.

    Science.gov (United States)

    Manenti, Rosa; Brambilla, Michela; Benussi, Alberto; Rosini, Sandra; Cobelli, Chiara; Ferrari, Clarissa; Petesi, Michela; Orizio, Italo; Padovani, Alessandro; Borroni, Barbara; Cotelli, Maria

    2016-05-01

    Parkinson's disease (PD) is characterized by both motor and cognitive deficits. In PD, physical exercise has been found to improve physical functioning. Recent studies demonstrated that repeated sessions of transcranial direct current stimulation led to an increased performance in cognitive and motor tasks in patients with PD. The present study investigated the effects of anodal transcranial direct current stimulation applied over the dorsolateral prefrontal cortex and combined with physical therapy in PD patients. A total of 20 patients with PD were assigned to 1 of 2 study groups: group 1, anodal transcranial direct current stimulation plus physical therapy (n = 10) or group 2, placebo transcranial direct current stimulation plus physical therapy (n = 10). The 2 weeks of treatment consisted of daily direct current stimulation application for 25 minutes during physical therapy. Long-term effects of treatment were evaluated on clinical, neuropsychological, and motor task performance at 3-month follow-up. An improvement in motor abilities and a reduction of depressive symptoms were observed in both groups after the end of treatment and at 3-month follow-up. The Parkinson's Disease Cognitive Rating Scale and verbal fluency test performances increased only in the anodal direct current stimulation group with a stable effect at follow-up. The application of anodal transcranial direct current stimulation may be a relevant tool to improve cognitive abilities in PD and might be a novel therapeutic strategy for PD patients with mild cognitive impairment. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

  4. 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.

  5. 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.

  6. Can Transcranial Direct Current Stimulation Augment Extinction of Conditioned Fear?

    Science.gov (United States)

    van ’t Wout, Mascha; Mariano, Timothy Y.; Garnaat, Sarah L.; Reddy, Madhavi K.; Rasmussen, Steven A.; Greenberg, Benjamin D.

    2016-01-01

    Background Exposure-based therapy parallels extinction learning of conditioned fear. Prior research points to the ventromedial prefrontal cortex as a potential site for the consolidation of extinction learning and subsequent retention of extinction memory. Objective/hypothesis The present study aimed to evaluate whether the application of non-invasive transcranial direct current stimulation (tDCS) during extinction learning enhances late extinction and early recall in human participants. Methods Forty-four healthy volunteers completed a 2-day Pavlovian fear conditioning, extinction, and recall paradigm while skin conductance activity was continuously measured. Twenty-six participants received 2 mA anodal tDCS over EEG coordinate AF3 during extinction of a first conditioned stimulus. The remaining 18 participants received similar tDCS during extinction of a second conditioned stimulus. Sham stimulation was applied for the balance of extinction trials in both groups. Normalized skin conductance changes were analyzed using linear mixed models to evaluate effects of tDCS over late extinction and early recall trials. Results We observed a significant interaction between timing of tDCS during extinction blocks and changes in skin conductance reactivity over late extinction trials. These data indicate that tDCS was associated with accelerated late extinction learning of a second conditioned stimulus after tDCS was combined with extinction learning of a previous conditioned stimulus. No significant effects of tDCS timing were observed on early extinction recall. Conclusions Results could be explained by an anxiolytic aftereffect of tDCS and extend previous studies on tDCS-induced modulation of fear and threat related learning processes. These findings support further exploration of the clinical use of tDCS. PMID:27037186

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

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    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...

  8. Effects of Transcranial Direct Current Stimulation on episodic memory related to emotional visual stimuli.

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    Penolazzi, Barbara; Di Domenico, Alberto; Marzoli, Daniele; Mammarella, Nicola; Fairfield, Beth; Franciotti, Raffaella; Brancucci, Alfredo; Tommasi, Luca

    2010-05-13

    The present study investigated emotional memory following bilateral transcranial electrical stimulation (direct current of 1 mA, for 20 minutes) over fronto-temporal cortical areas of healthy participants during the encoding of images that differed in affective arousal and valence. The main result was a significant interaction between the side of anodal stimulation and image emotional valence. Specifically, right anodal/left cathodal stimulation selectively facilitated the recall of pleasant images with respect to both unpleasant and neutral images whereas left anodal/right cathodal stimulation selectively facilitated the recall of unpleasant images with respect to both pleasant and neutral images. From a theoretical perspective, this double dissociation between the side of anodal stimulation and the advantage in the memory performance for a specific type of stimulus depending on its pleasantness supported the specific-valence hypothesis of emotional processes, which assumes a specialization of the right hemisphere in processing unpleasant stimuli and a specialization of the left hemisphere in processing pleasant stimuli. From a methodological point of view, first we found tDCS effects strictly dependent on the stimulus category, and second a pattern of results in line with an interfering and inhibitory account of anodal stimulation on memory performance. These findings need to be carefully considered in applied contexts, such as the rehabilitation of altered emotional processing or eye-witness memory, and deserve to be further investigated in order to understand their underlying mechanisms of action.

  9. Effects of Transcranial Direct Current Stimulation on episodic memory related to emotional visual stimuli.

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    Barbara Penolazzi

    2010-05-01

    Full Text Available The present study investigated emotional memory following bilateral transcranial electrical stimulation (direct current of 1 mA, for 20 minutes over fronto-temporal cortical areas of healthy participants during the encoding of images that differed in affective arousal and valence. The main result was a significant interaction between the side of anodal stimulation and image emotional valence. Specifically, right anodal/left cathodal stimulation selectively facilitated the recall of pleasant images with respect to both unpleasant and neutral images whereas left anodal/right cathodal stimulation selectively facilitated the recall of unpleasant images with respect to both pleasant and neutral images. From a theoretical perspective, this double dissociation between the side of anodal stimulation and the advantage in the memory performance for a specific type of stimulus depending on its pleasantness supported the specific-valence hypothesis of emotional processes, which assumes a specialization of the right hemisphere in processing unpleasant stimuli and a specialization of the left hemisphere in processing pleasant stimuli. From a methodological point of view, first we found tDCS effects strictly dependent on the stimulus category, and second a pattern of results in line with an interfering and inhibitory account of anodal stimulation on memory performance. These findings need to be carefully considered in applied contexts, such as the rehabilitation of altered emotional processing or eye-witness memory, and deserve to be further investigated in order to understand their underlying mechanisms of action.

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

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    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.

  11. The effect of transcranial direct current stimulation on social cognition in schizophrenia: A preliminary study.

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    Rassovsky, Yuri; Dunn, Walter; Wynn, Jonathan; Wu, Allan D; Iacoboni, Marco; Hellemann, Gerhard; Green, Michael F

    2015-07-01

    In this preliminary study, we examined the effect of transcranial direct current stimulation (tDCS) on social cognition in 36 individuals with schizophrenia. Participants received a baseline assessment and one week later received either anodal, cathodal, or sham tDCS, with 12 participants randomized to each condition. A single 20-minute session tDCS was administered bilaterally over the dorsolateral prefrontal cortex (centered at positions Fp1 and Fp2) at 2 mA. Among the 4 social cognitive tasks, participants showed a significant improvement on one of them, emotion identification, following anodal stimulation. Findings demonstrate the safety of this procedure and suggest potential therapeutic effects on one aspect of social cognition in schizophrenia. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. No Modulation of Visual Cortex Excitability by Transcranial Direct Current Stimulation.

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    Sabrina Brückner

    Full Text Available Measuring phosphene thresholds (PTs is often used to investigate changes in the excitability of the human visual cortex through different brain stimulation methods like repetitive transcranial magnetic stimulation (rTMS or transcranial direct current stimulation (tDCS. In several studies, PT increase or decrease has been shown after rTMS or tDCS application. Recently, using PT measurements we showed that the state of the neurons in the visual cortex after rTMS might have an influence on the modulatory effects of stimulation. In the present study we aimed to investigate whether visual cortex activity following stimulation influences the modulatory effects of tDCS as well. In a between-group design, anodal or cathodal tDCS was applied to the visual cortex twice per subject, with either high or low visual demand following stimulation. We observed no modulation of PT neither directly following both anodal and cathodal tDCS nor following the visual demand periods. We rather found high inter-individual variability in the response to tDCS, and intra-individual reliability in the direction of modulation was observed for cathodal tDCS only. Thus, our results do not confirm the modulatory effects of tDCS on visual cortex excitability published previously. Moreover, they support the confirmation that tDCS effects have little reliability on varied TMS outcome measurements.

  13. Transcranial direct current stimulation enhances propulsion during walking

    NARCIS (Netherlands)

    van Asseldonk, Edwin H.F.; Jensen, W.; Andersen, O.K.; Akay, M

    2014-01-01

    Transcranial direct current stimulation (tDCS) has been shown to improve force generation and control in single leg joints in healthy subjects and stroke survivors. However, it is unknown whether these effects also result in improved force production and coordination during walking. Here we

  14. Right prefrontal cortex transcranial direct current stimulation enhances multi-day savings in sensorimotor adaptation.

    Science.gov (United States)

    Seidler, Rachael D; Gluskin, Brittany S; Greeley, Brian

    2017-01-01

    We have previously reported that visuospatial working memory performance and magnitude of activation in the right dorsolateral prefrontal cortex predict the rate of visuomotor adaptation. Recent behavioral studies suggest that sensorimotor savings, or faster relearning on second exposure to a task, are due to recall of these early, strategic components of adaptation. In the present study we applied anodal transcranial direct current stimulation to right or left prefrontal cortex or left motor cortex. We found that all groups adapted dart throwing movements while wearing prism lenses at the same rate as subjects receiving sham stimulation on day 1 On test day 2, which was conducted a few days later, the right prefrontal and left motor cortex groups adapted faster than the sham group. Moreover, only the right prefrontal group exhibited greater savings, expressed as a greater difference between day 1 and day 2 errors, compared with sham stimulation. These findings support the hypothesis that the right prefrontal cortex contributes to sensorimotor adaptation and savings. We have previously reported that visuospatial working memory performance and magnitude of activation in the right dorsolateral prefrontal cortex predict the rate of manual visuomotor adaptation. Sensorimotor savings, or faster adaptation to a previously experienced perturbation, has been recently linked to cognitive processes. We show that facilitating the right prefrontal cortex with anodal transcranial direct current stimulation enhances sensorimotor savings compared with sham stimulation. Copyright © 2017 the American Physiological Society.

  15. Reading changes in children and adolescents with dyslexia after transcranial direct current stimulation.

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    Costanzo, Floriana; Varuzza, Cristiana; Rossi, Serena; Sdoia, Stefano; Varvara, Pamela; Oliveri, Massimiliano; Koch, Giacomo; Vicari, Stefano; Menghini, Deny

    2016-03-23

    Noninvasive brain stimulation offers the possibility to induce changes in cortical excitability and it is an interesting option as a remediation tool for the treatment of developmental disorders. This study aimed to investigate the effect of transcranial direct current stimulation (tDCS) on reading and reading-related skills of children and adolescents with dyslexia. Nineteen children and adolescents with dyslexia performed different reading and reading-related tasks (word, nonword, and text reading; lexical decision; phonemic blending; verbal working memory; rapid automatized naming) in a baseline condition without tDCS and after 20 min of exposure to three different tDCS conditions: left anodal/right cathodal tDCS to enhance left lateralization of the parietotemporal region, right anodal/left cathodal tDCS to enhance right lateralization of the parietotemporal region, and sham tDCS. In text reading, results showed a significant reduction in errors after left anodal/right cathodal tDCS and an increase in errors after left cathodal/right anodal tDCS. No effect was found in the other reading and reading-related tasks. Our findings indicate for the first time that one session of tDCS modulates some aspects of reading performance of children and adolescents with dyslexia and that the effect is polarity dependent. These single-session results support a potential role of tDCS for developing treatment protocols and suggest possible parameters for tDCS treatment customization in children and adolescents with dyslexia.

  16. Transcranial direct current stimulation over the left prefrontal cortex increases randomness of choice in instrumental learning.

    Science.gov (United States)

    Turi, Zsolt; Mittner, Matthias; Opitz, Alexander; Popkes, Miriam; Paulus, Walter; Antal, Andrea

    2015-02-01

    There is growing evidence from neuro-computational studies that instrumental learning involves the dynamic interaction of a computationally rigid, low-level striatal and a more flexible, high-level prefrontal component. To evaluate the role of the prefrontal cortex in instrumental learning, we applied anodal transcranial direct current stimulation (tDCS) optimized for the left dorsolateral prefrontal cortex, by using realistic MR-derived finite element model-based electric field simulations. In a study with a double-blind, sham-controlled, repeated-measures design, sixteen male participants performed a probabilistic learning task while receiving anodal and sham tDCS in a counterbalanced order. Compared to sham tDCS, anodal tDCS significantly increased the amount of maladaptive shifting behavior after optimal outcomes during learning when reward probabilities were highly dissociable. Derived parameters of the Q-learning computational model further revealed a significantly increased model parameter that was sensitive to random action selection in the anodal compared to the sham tDCS session, whereas the learning rate parameter was not influenced significantly by tDCS. These results congruently indicate that prefrontal tDCS during instrumental learning increased randomness of choice, possibly reflecting the influence of the cognitive prefrontal component. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Polarity Specific Suppression Effects of Transcranial Direct Current Stimulation for Tinnitus

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    Kathleen Joos

    2014-01-01

    Full Text Available Tinnitus is the perception of a sound in the absence of an external auditory stimulus and affects 10–15% of the Western population. Previous studies have demonstrated the therapeutic effect of anodal transcranial direct current stimulation (tDCS over the left auditory cortex on tinnitus loudness, but the effect of this presumed excitatory stimulation contradicts with the underlying pathophysiological model of tinnitus. Therefore, we included 175 patients with chronic tinnitus to study polarity specific effects of a single tDCS session over the auditory cortex (39 anodal, 136 cathodal. To assess the effect of treatment, we used the numeric rating scale for tinnitus loudness and annoyance. Statistical analysis demonstrated a significant main effect for tinnitus loudness and annoyance, but for tinnitus annoyance anodal stimulation has a significantly more pronounced effect than cathodal stimulation. We hypothesize that the suppressive effect of tDCS on tinnitus loudness may be attributed to a disrupting effect of ongoing neural hyperactivity, independent of the inhibitory or excitatory effects and that the reduction of annoyance may be induced by influencing adjacent or functionally connected brain areas involved in the tinnitus related distress network. Further research is required to explain why only anodal stimulation has a suppressive effect on tinnitus annoyance.

  18. The effects of combined repetitive transcranial magnetic stimulation and transcranial direct current stimulation on motor function in patients with stroke.

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    Kwon, Tae Gun; Park, Eunhee; Kang, Chung; Chang, Won Hyuk; Kim, Yun-Hee

    2016-11-22

    Both transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), when provided to stroke patients in combination with motor training, enhance therapeutic efficacy and motor function. However, the majority of previous studies have only examined a single treatment modality. The authors investigated the modulating influence of combination dual-mode brain stimulation upon bihemispheric stimulation with motor training in stroke patients. Twenty stroke patients with hemiparesis underwent five randomly arranged sessions of diverse combinations of rTMS and tDCS. We applied cathodal or anodal tDCS over the contralesional primary motor cortex (cM1) and 10 Hz rTMS over the ipsilesional primary motor cortex (iM1) in a simultaneous or preconditioning method including sham stimulation. Immediately after dual-mode stimulation, sequential hand motor training was performed for 5 minutes. The total pulses of rTMS and the duration of tDCS and motor training were the same for all sessions. Cortical excitability and sequential motor performance were evaluated before and after each session. Motor function and corticomotor excitability following simultaneous stimulation via cathodal tDCS over the cM1 combined with 10 Hz rTMS over the iM1 were significantly increased after the intervention, with significantly greater motor improvement than seen with other treatment conditions (P motor performance in stroke patients than other combination methods. This result seemed to be related to effective modulation of interhemispheric imbalance of cortical excitability by dual-mode stimulation.

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

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    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.

  20. Effects of frontal transcranial direct current stimulation on emotional processing and mood in healthy humans

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    Michael A. Nitsche

    2012-06-01

    Full Text Available The prefrontal cortex is involved in mood and emotional processing. In patients suffering from depression, the left dorsolateral prefrontal cortex is hypoactive, while activity of the right dorsolateral prefrontal cortex is enhanced. Counterbalancing these pathological excitability alterations by repetitive transcranial magnetic stimulation (rTMS or transcranial direct current stimulation (tDCS improves mood in these patients. In healthy subjects, however, rTMS of the same areas has no major effect, and the effects of tDCS are mixed. We aimed to evaluate the effects of prefrontal tDCS on mood and mood-related cognitive processing in healthy humans. In a first study, we administered excitability-enhancing anodal, excitability-diminishing cathodal and placebo tDCS to the left dorsolateral prefrontal cortex, combined with antagonistic stimulation of the right frontopolar cortex, and tested acute mood changes by an adjective checklist. Subjective mood was not influenced by tDCS. Emotional face identification, however, which was explored in a second experiment, was subtly improved by a tDCS-driven excitability modulation of the prefrontal cortex, markedly by anodal tDCS of the left dorsolateral prefrontal cortex for positive emotional content. We conclude that tDCS of the prefrontal cortex improves mood processing in healthy subjects, but does not influence subjective mood state.

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

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    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.

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

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    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.

  3. 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.

  4. Does prefrontal cortex transcranial direct current stimulation influence the oxygen uptake at rest and post-exercise?

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    Montenegro, R; Okano, A H; Cunha, F A; Fontes, E B; Farinatti, P

    2014-06-01

    The study evaluated the effect of transcranial direct current stimulation (tDCS) applied over prefrontal cortex on the oxygen uptake (V˙ O2) at rest and during post-exercise recovery. The V˙ O2 was assessed in eleven healthy subjects before, during tDCS (sham or anodal tDCS, 2 mA, 20 min), and 30-min following isocaloric aerobic exercise (~200 kcal). During tDCS, no changes were observed on V˙ O2 compared to baseline (P=0.95) and sham condition (P=0.85). The association between isocaloric exercise and anodal tDCS increased the V˙ O2 throughout 30-min recovery compared to sham condition (PEPOC) period, after anodal tDCS was approximately 19% higher compared to the sham condition (PEPOC, enhancing the V˙ O2 and energy expenditure at least for 30-min of recovery. © Georg Thieme Verlag KG Stuttgart · New York.

  5. Mood and cognitive function following repeated transcranial direct current stimulation in healthy volunteers: a preliminary report.

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    Motohashi, Nobutaka; Yamaguchi, Masayasu; Fujii, Tomokazu; Kitahara, Yuichi

    2013-01-01

    Although mood and cognitive function have been reported to change following transcranial direct current stimulation (tDCS) in patients with neurological and psychiatric diseases, little is known about the effects of repeated tDCS on mood and cognition in healthy humans. We recruited 11 healthy male participants for this single-blind, sham-controlled crossover trial. We used Profile of Mood States, brief-form (POMS), and CogHealth (Detection Task, Identification Task, One Back Task, One Card Learning Task and Continuous Monitoring Task) to evaluate the changes in mood and cognitive function, respectively, before and immediately after 4-daily, 20 min, 1 mA sham or anodal tDCS over the left dorsolateral prefrontal cortex (DLPFC). While there were no significant changes in six factors of POMS and performance (speed and accuracy) of CogHealth between sham and anodal stimulation, the accuracy of One Card Learning was increased at the end of the experiment. Signal detection analyses revealed that both hit rate and discriminability were improved in this task. These results suggest that 4-daily anodal tDCS over left DLPFC may not change mood and cognitive function in healthy subjects, and further support the safety of tDCS. A slight improvement in a visual recognition and learning task at the end of experiment may be susceptible to practice effects. Copyright © 2013 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

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

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    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.

  7. Effects of transcranial direct current stimulation on the recognition of bodily emotions from point light displays.

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    Sharona eVonck

    2015-08-01

    Full Text Available Perceiving human motion, recognizing actions and interpreting emotional body language are tasks we perform daily and which are supported by a network of brain areas including the human posterior superior temporal sulcus (pSTS. Here, we applied transcranial direct current stimulation with anodal (excitatory or cathodal (inhibitory electrodes mounted over right pSTS (target and orbito-frontal cortex (reference while healthy participants performed a bodily emotion recognition task using biological motion point light displays (PLDs. Performance (accuracy and reaction times was also assessed on a control task which was matched to the emotion recognition task in terms of cognitive and motor demands. Each subject participated in two experimental sessions, receiving either anodal or cathodal stimulation, which were separated by one week to avoid residual effects of previous stimulations.Overall, tDCS brain stimulation did not affect the recognition of emotional states from PLDs. However, when emotions with a negative or positive-neutral emotional valence were analyzed separately, effects of stimulation were shown for recognizing emotions with a negative emotional valence (sadness & anger, indicating increased recognition performance when receiving anodal (excitatory stimulation compared to cathodal (inhibitory stimulation over pSTS. No stimulation effects were shown for the recognition of emotions with positive-neutral emotional valences. These findings extend previous studies showing structure-function relationships between STS and biological motion processing from PLDs and provide indications that stimulation effects may be modulated by the emotional valence of the stimuli.

  8. Effects of transcranial direct current stimulation (tDCS on consolidation of fear memory

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    Manish eAsthana

    2013-09-01

    Full Text Available It has been shown that applying transcranial direct current stimulation (tDCS over the dorsolateral prefrontal cortex (DLPFC influences declarative memory processes. This study investigates the efficacy of tDCS on emotional memory consolidation, especially experimental fear conditioning. We applied an auditory fear-conditioning paradigm; in which two differently colored squares (blue and yellow were presented as conditioned stimuli (CS and an auditory stimulus as unconditioned stimulus (UCS. Sixty-nine participants were randomly assigned into three groups: anodal, cathodal and sham stimulation. The participants of the two active groups (i.e., anodal and cathodal received tDCS over the left DLPFC for 12 minutes after fear conditioning. The effect of fear conditioning and consolidation (24 hours later was measured by assessing the skin conductance response (SCR to the CS. The results provide evidence that cathodal stimulation of the left DLPFC leads to an inhibitory effect on fear memory consolidation compared to anodal and sham stimulation, as indicated by decreased SCRs to CS+ presentation during extinction training at day 2. In conclusion, current work suggests that cathodal stimulation interferes with processes of fear memory consolidation.

  9. Treatment of Memory Disorders in Gulf War Illness with High-Definition Transcranial Direct Cortical Stimulation

    Science.gov (United States)

    2017-10-01

    AWARD NUMBER: W81XWH-16-1-0521 TITLE: Treatment of Memory Disorders in Gulf War Illness with High- Definition Transcranial Direct Cortical...Sep 2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Treatment of Memory Disorders in Gulf War Illness with High-Definition Transcranial Direct...0521 15. SUBJECT TERMS Gulf War Illness; High Definition Transcranial Direct Current Stimulation; word finding; semantic memory 16. SECURITY

  10. Transcranial Direct Current Stimulation combined with treadmill training in the subacute phase following stroke: case series

    DEFF Research Database (Denmark)

    Figlewski, Krystian; Nielsen, Jørgen Feldbæk; Blicher, Jakob

    Background Stroke is a common cause of gait impairment and regaining a normal gait is a major target in stroke rehabilitation. To facilitate motor recovery after stroke, a variety of experimental approaches have been tested. Recent developments include non-invasive brain stimulation techniques...... such as transcranial Direct Current Stimulation (tDCS). In neurophysiologic studies an imbalance of interhemispheric interactions has been demonstrated which is believed to interfere with the recovery process. This imbalance can be ameliorated by upregulation of the excitability in the lesioned hemisphere applying...... (Fig.3). No major side effects were reported. Conclusions This case series supports the feasibility of anodal tDCS combined with body weight support treadmill training and demonstrates that this type of intervention carries potential for strategy to improve gait recovery in early phase...

  11. Transcranial brain stimulation: clinical applications and future directions.

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    Najib, Umer; Bashir, Shahid; Edwards, Dylan; Rotenberg, Alexander; Pascual-Leone, Alvaro

    2011-04-01

    Noninvasive brain stimulation is a valuable investigative tool and has potential therapeutic applications in cognitive neuroscience, neurophysiology, psychiatry, and neurology. Transcranial magnetic stimulation (TMS) is particularly useful to establish and map causal brain-behavior relations in motor and nonmotor cortical areas. Neuronavigated TMS is able to provide precise information related to the individual's functional anatomy that can be visualized and used during surgical interventions and critically aid in presurgical planning, reducing the need for riskier and more cumbersome intraoperative or invasive mapping procedures. This article reviews methodological aspects, clinical applications, and future directions of TMS-based mapping. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Effects of transcranial direct current stimulation (tDCS) on pain distress tolerance: a preliminary study

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    Mariano, Timothy Y.; Wout, Mascha van’t; Jacobson, Benjamin L.; Garnaat, Sarah L.; Kirschner, Jason L.; Rasmussen, Steven A.; Greenberg, Benjamin D.

    2015-01-01

    Objective Pain remains a critical medical challenge. Current treatments target nociception without addressing affective symptoms. Medically intractable pain is sometimes treated with cingulotomy or deep brain stimulation to increase tolerance of pain-related distress. Transcranial direct current stimulation (tDCS) may noninvasively modulate cortical areas related to sensation and pain representations. The present study aimed to test the hypothesis that cathodal (“inhibitory”) stimulation targeting left dorsal anterior cingulate cortex (dACC) would increase tolerance to distress from acute painful stimuli versus anodal stimulation. Methods Forty healthy volunteers received both anodal and cathodal stimulation. During stimulation, we measured pain distress tolerance with three tasks: pressure algometer, cold pressor, and breath holding. We measured pain intensity with a visual-analog scale before and after each task. Results Mixed ANOVA revealed that mean cold pressor tolerance tended to be higher with cathodal versus anodal stimulation (p = 0.055) for participants self-completing the task. Pressure algometer (p = 0.81) and breath holding tolerance (p = 0.19) did not significantly differ. The pressure algometer exhibited a statistically significant order effect irrespective of stimulation polarity (all p Pain intensity ratings increased acutely after cold pressor and pressure algometer tasks (both p pain ratings tended to rise less after cathodal versus anodal tDCS (p = 0.072). Conclusions Although our primary results were nonsignificant, there is a preliminary suggestion that cathodal tDCS targeting left dACC may increase pain distress tolerance to cold pressor. Pressure algometer results are consistent with task-related sensitization. Future studies are needed to refine this novel approach for pain neuromodulation. PMID:26115372

  13. Combined Dextroamphetamine and Transcranial Direct Current Stimulation in Poststroke Aphasia.

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    Keser, Zafer; Dehgan, Michelle Weber; Shadravan, Shaparak; Yozbatiran, Nuray; Maher, Lynn M; Francisco, Gerard E

    2017-10-01

    There is a growing need for various effective adjunctive treatment options for speech recovery after stroke. A pharmacological agent combined with noninvasive brain stimulation has not been previously reported for poststroke aphasia recovery. In this "proof of concept" study, we aimed to test the safety of a combined intervention consisting of dextroamphetamine, transcranial direct current stimulation, and speech and language therapy in subjects with nonfluent aphasia. Ten subjects with chronic nonfluent aphasia underwent two experiments where they received dextroamphetamine or placebo along with transcranial direct current stimulation and speech and language therapy on two separate days. The Western Aphasia Battery-Revised was used to monitor changes in speech performance. No serious adverse events were observed. There was no significant increase in blood pressure with amphetamine or deterioration in speech and language performance. Western Aphasia Battery-Revised aphasia quotient and language quotient showed a statistically significant increase in the active experiment. Comparison of proportional changes of aphasia quotient and language quotient in active experiment with those in placebo experiment showed significant difference. We showed that the triple combination therapy is safe and implementable and seems to induce positive changes in speech and language performance in the patients with chronic nonfluent aphasia due to stroke.

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

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    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.

  15. Effects of transcranial direct current stimulation on the control of finger force during dexterous manipulation in healthy older adults.

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    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.

  16. Effects of transcranial direct current stimulation on the control of finger force during dexterous manipulation in healthy older adults.

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    Parikh, Pranav J; Cole, Kelly J

    2015-01-01

    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.

  17. Mechanisms and Effects of Transcranial Direct Current Stimulation

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    James Giordano

    2017-02-01

    Full Text Available The US Air Force Office of Scientific Research convened a meeting of researchers in the fields of neuroscience, psychology, engineering, and medicine to discuss most pressing issues facing ongoing research in the field of transcranial direct current stimulation (tDCS and related techniques. In this study, we present opinions prepared by participants of the meeting, focusing on the most promising areas of research, immediate and future goals for the field, and the potential for hormesis theory to inform tDCS research. Scientific, medical, and ethical considerations support the ongoing testing of tDCS in healthy and clinical populations, provided best protocols are used to maximize safety. Notwithstanding the need for ongoing research, promising applications include enhancing vigilance/attention in healthy volunteers, which can accelerate training and support learning. Commonly, tDCS is used as an adjunct to training/rehabilitation tasks with the goal of leftward shift in the learning/treatment effect curves. Although trials are encouraging, elucidating the basic mechanisms of tDCS will accelerate validation and adoption. To this end, biomarkers (eg, clinical neuroimaging and findings from animal models can support hypotheses linking neurobiological mechanisms and behavioral effects. Dosage can be optimized using computational models of current flow and understanding dose–response. Both biomarkers and dosimetry should guide individualized interventions with the goal of reducing variability. Insights from other applied energy domains, including ionizing radiation, transcranial magnetic stimulation, and low-level laser (light therapy, can be prudently leveraged.

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

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    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.

  19. The temporary and accumulated effects of transcranial direct current stimulation for the treatment of advanced Parkinson’s disease monkeys

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    Li, Hao; Lei, Xiaoguang; Yan, Ting; Li, Hongwei; Huang, Baihui; Li, Ling; Xu, Liqi; Liu, Li; Chen, Nanhui; Lü, Longbao; Ma, Yuanye; Xu, Lin; Li, Jiali; Wang, Zhengbo; Zhang, Baorong; Hu, Xintian

    2015-01-01

    Transcranial direct current stimulation (tDCS) is a useful noninvasive technique of cortical brain stimulation for the treatment of neurological disorders. Clinical research has demonstrated tDCS with anodal stimulation of primary motor cortex (M1) in Parkinson’s disease (PD) patients significantly improved their motor function. However, few studies have been focused on the optimization of parameters which contributed significantly to the treatment effects of tDCS and exploration of the underline neuronal mechanisms. Here, we used different stimulation parameters of anodal tDCS on M1 for the treatment of aged advanced PD monkeys induced with 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) administration, and then analyzed the temporary and accumulated effects of tDCS treatment. The results indicated anodal tDCS on M1 very significantly improved motor ability temporarily; importantly, the treatment effects of anodal tDCS on M1 were quantitatively correlated to the accumulated stimulation instead of the stimuli intensity or duration respectively. In addition, c-fos staining showed tDCS treatment effects activated the neurons both in M1 and substantia nigra (SN). Therefore, we propose that long time and continue anodal tDCS on M1 is a better strategy to improve the motor symptoms of PD than individual manipulation of stimuli intensity or duration. PMID:26220760

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

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    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.

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

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    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.

  2. Sex Mediates the Effects of High-Definition Transcranial Direct Current Stimulation on "Mind-Reading".

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    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.

  3. Can Transcranial Direct Current Stimulation Improve Cognitive Functioning in Adults with Schizophrenia?

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    Schretlen, David J; van Steenburgh, Joseph J; Varvaris, Mark; Vannorsdall, Tracy D; Andrejczuk, Megan A; Gordon, Barry

    Cognitive impairment is nearly ubiquitous in schizophrenia. First-degree relatives of persons with schizophrenia often show similar but milder deficits. Current methods for the treatment of schizophrenia are often ineffective in cognitive remediation. Since transcranial direct current stimulation (tDCS) can enhance cognitive functioning in healthy adults, it might provide a viable option to enhance cognition in schizophrenia. We sought to explore whether tDCS can be tolerated by persons with schizophrenia and potentially improve their cognitive functioning. We examined the effects of anodal versus cathodal tDCS on working memory and other cognitive tasks in five outpatients with schizophrenia and six first-degree relatives of persons with schizophrenia. Each participant completed tasks thought to be mediated by the prefrontal cortex during two 30-minute sessions of tDCS to the left and right dorsolateral prefrontal cortex (DLPFC). Anodal stimulation over the left DLPFC improved performance relative to cathodal stimulation on measures of working memory and aspects of verbal fluency relevant to word retrieval. The patient group showed differential changes in novel design production without alteration of overall productivity, suggesting that tDCS might be capable of altering self-monitoring and executive control. All participants tolerated tDCS well. None withdrew from the study or experienced any adverse reaction. We conclude that adults with schizophrenia can tolerate tDCS while engaging in cognitive tasks and that tDCS can alter their performance.

  4. Using Transcranial Direct Current Stimulation to Enhance Creative Cognition: Interactions between Task, Polarity, and Stimulation Site

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    Adam B. Weinberger

    2017-05-01

    Full Text Available Creative cognition is frequently described as involving two primary processes, idea generation and idea selection. A growing body of research has used transcranial direct current stimulation (tDCS to examine the neural mechanisms implicated in each of these processes. This literature has yielded a diverse set of findings that vary depending on the location and type (anodal, cathodal, or both of electrical stimulation employed, as well as the task’s reliance on idea generation or idea selection. As a result, understanding the interactions between stimulation site, polarity and task demands is required to evaluate the potential of tDCS to enhance creative performance. Here, we review tDCS designs that have elicited reliable and dissociable enhancements for creative cognition. Cathodal stimulation over the left inferior frontotemporal cortex has been associated with improvements on tasks that rely primarily on idea generation, whereas anodal tDCS over left dorsolateral prefrontal cortex (DLPFC and frontopolar cortex has been shown to augment performance on tasks that impose high demands on creative idea selection. These results highlight the functional selectivity of tDCS for different components of creative thinking and confirm the dissociable contributions of left dorsal and inferior lateral frontotemporal cortex for different creativity tasks. We discuss promising avenues for future research that can advance our understanding of the effectiveness of tDCS as a method to enhance creative cognition.

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

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    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.

  6. Combined effects of cerebellar transcranial direct current stimulation and transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic brain stroke: A pilot, single blind, randomized controlled trial.

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    Picelli, Alessandro; Chemello, Elena; Castellazzi, Paola; Filippetti, Mirko; Brugnera, Annalisa; Gandolfi, Marialuisa; Waldner, Andreas; Saltuari, Leopold; Smania, Nicola

    2018-01-01

    Preliminary evidence showed additional effects of anodal transcranial direct current stimulation over the damaged cerebral hemisphere combined with cathodal transcutaneous spinal direct current stimulation during robot-assisted gait training in chronic stroke patients. This is consistent with the neural organization of locomotion involving cortical and spinal control. The cerebellum is crucial for locomotor control, in particular for avoidance of obstacles, and adaptation to novel conditions during walking. Despite its key role in gait control, to date the effects of transcranial direct current stimulation of the cerebellum have not been investigated on brain stroke patients treated with robot-assisted gait training. To evaluate the effects of cerebellar transcranial direct current stimulation combined with transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic brain stroke. After balanced randomization, 20 chronic stroke patients received ten, 20-minute robot-assisted gait training sessions (five days a week, for two consecutive weeks) combined with central nervous system stimulation. Group 1 underwent on-line cathodal transcranial direct current stimulation over the contralesional cerebellar hemisphere + cathodal transcutaneous spinal direct current stimulation. Group 2 received on-line anodal transcranial direct current stimulation over the damaged cerebral hemisphere + cathodal transcutaneous spinal direct current stimulation. The primary outcome was the 6-minute walk test performed before, after, and at follow-up at 2 and 4 weeks post-treatment. The significant differences in the 6-minute walk test noted between groups at the first post-treatment evaluation (p = 0.041) were not maintained at either the 2-week (P = 0.650) or the 4-week (P = 0.545) follow-up evaluations. Our preliminary findings support the hypothesis that cathodal transcranial direct current stimulation over the contralesional

  7. Transcranial Direct Current Stimulation and Power Spectral Parameters: a tDCS/EEG co-registration study

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    Anna Lisa Mangia

    2014-08-01

    Full Text Available Transcranial direct current stimulation (tDCS delivers low electric currents to the brain through the scalp. Constant electric currents induce shifts in neuronal membrane excitability, resulting in secondary changes in cortical activity. Concomitant electroencephalography (EEG monitoring during tDCS can provide valuable information on the tDCS mechanisms of action. This study examined the effects of anodal tDCS on spontaneous cortical activity in a resting brain to disclose possible modulation of spontaneous oscillatory brain activity. EEG activity was measured in ten healthy subjects during and after a session of anodal stimulation of the postero-parietal cortex to detect the tDCS-induced alterations. Changes in the theta, alpha, beta and gamma power bands were investigated. Three main findings emerged: 1 an increase in theta band activity during the first minutes of stimulation; 2 an increase in alpha and beta power during and after stimulation; 3 a widespread activation in several brain regions.

  8. Transcranial direct current stimulation of right dorsolateral prefrontal cortex does not affect model-based or model-free reinforcement learning in humans.

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    Smittenaar, Peter; Prichard, George; FitzGerald, Thomas H B; Diedrichsen, Joern; Dolan, Raymond J

    2014-01-01

    There is broad consensus that the prefrontal cortex supports goal-directed, model-based decision-making. Consistent with this, we have recently shown that model-based control can be impaired through transcranial magnetic stimulation of right dorsolateral prefrontal cortex in humans. We hypothesized that an enhancement of model-based control might be achieved by anodal transcranial direct current stimulation of the same region. We tested 22 healthy adult human participants in a within-subject, double-blind design in which participants were given Active or Sham stimulation over two sessions. We show Active stimulation had no effect on model-based control or on model-free ('habitual') control compared to Sham stimulation. These null effects are substantiated by a power analysis, which suggests that our study had at least 60% power to detect a true effect, and by a Bayesian model comparison, which favors a model of the data that assumes stimulation had no effect over models that assume stimulation had an effect on behavioral control. Although we cannot entirely exclude more trivial explanations for our null effect, for example related to (faults in) our experimental setup, these data suggest that anodal transcranial direct current stimulation over right dorsolateral prefrontal cortex does not improve model-based control, despite existing evidence that transcranial magnetic stimulation can disrupt such control in the same brain region.

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

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    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.

  10. Transcranial direct current stimulation modulates human color discrimination in a pathway specific manner.

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    Thiago Leiros eCosta

    2012-09-01

    Full Text Available Previous research showed that Transcranial Direct Current Stimulation (tDCS can modulate visual cortex excitability. However, there is no experiment on the effects of tDCS on color perception to date. The present study aimed to investigate the effects of tDCS on color discrimination tasks. 15 healthy subjects (mean age of 25.6 ± 4.4 years were tested with Cambridge Color Test 2.0 (Trivector and Ellipses protocols and a Forced-choice Spatial Color Contrast Sensitivity task (vertical red-green sinusoidal grating while receiving tDCS. Anodal, cathodal and sham tDCS were delivered at Oz for 22 minutes using two square electrodes (25cm2 with a current of 1.5mA in sessions separated by 7 days. Anodal tDCS significantly increased tritan sensitivity (p<0.01 and had no significant effect on protan, deutan or red-green grating discrimination. The effects on the tritan discrimination returned to baseline after 15 minutes (p<0.01. Cathodal tDCS reduced the sensitivity in the deutan axis and increased sensitivity in the tritan axis (p<0.05. The lack of anodal tDCS effects in the protan, deutan and red-green grating sensitivities could be explained by a ceiling effect since adults in this age range tend to have optimal color discrimination performance for these hues. The differential effects of cathodal tDCS on tritan and deutan sensitivities and the absence of the proposed ceiling effects for the tritan axes might be explained by Parvocellular (P and Koniocellular (K systems with regard to their functional, physiological and anatomical differences. The results also support the existence of a systematic segregation of P and K color-coding cells in V1. Future research and possible clinical implications are discussed.

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

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    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.

  12. Polarity-specific cortical effects of transcranial direct current stimulation in primary somatosensory cortex of healthy humans

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    Robert eRehmann

    2016-05-01

    Full Text Available Transcranial direct current stimulation (tDCS is a noninvasive stimulation method that has been shown to modulate the excitability of the motor and visual cortices in human subjects in a polarity dependent manner in previous studies. The aim of our study was to investigate whether anodal and cathodal tDCS can also be used to modulate the excitability of the human primary somatosensory cortex (S1. We measured paired-pulse suppression (PPS of somatosensory evoked potentials in 36 right-handed volunteers before and after anodal, cathodal or sham stimulation over the right non-dominant S1. Paired-pulse stimulation of the median nerve was performed at the dominant and non-dominant hand. After anodal tDCS, PPS was reduced in the ipsilateral S1 compared to sham stimulation, indicating an excitatory effect of anodal tDCS. In contrast, PPS in the stimulated left hemisphere was increased after cathodal tDCS, indicating an inhibitory effect of cathodal tDCS. Sham stimulation induced no pre-post differences. Thus, tDCS can be used to modulate the excitability of S1 in polarity-dependent manner, which can be assessed by paired-pulse suppression. An interesting topic for further studies could be the investigation of direct correlations between sensory changes and excitability changes induced by tDCS.

  13. Transcranial direct current stimulation enhances verbal working memory training performance over time and near transfer outcomes.

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    Richmond, Lauren L; Wolk, David; Chein, Jason; Olson, Ingrid R

    2014-11-01

    Studies attempting to increase working memory (WM) capacity show promise in enhancing related cognitive functions but have also raised criticism in the broader scientific community given the inconsistent findings produced by these studies. Transcranial direct current stimulation (tDCS) has been shown to enhance WM performance in a single session [Fregni, F., Boggio, P., Nitsche, M., Bermpohl, F., Anatal, A., Feredoes, E., et al. Anodal transcranial direct current stimulation of prefrontal cortex enhances working memory. Experimental Brain Research, 166, 23-30, 2005]; however, the extent to which tDCS might enhance learning on a WM training regime and the extent to which learning gains might transfer outside the training task remains largely unknown. To this end, participants engaged in an adaptive WM training task [previously utilized in Richmond, L., Morrison, A., Chein, J., & Olson, I. Working memory training and transfer in older adults. Psychology & Aging, 26, 813-822, 2011; Chein, J., & Morrison, A. Expanding the mind's workspace: Training and transfer effects with a complex working memory span task. Psychonomic Bulletin & Review, 17, 193-199, 2010] for 10 sessions over 2 weeks, concurrent with either active or sham stimulation of dorsolateral pFC. Before and after training, a battery of tests tapping domains known to relate to WM abilities was administered. Results show that tDCS enhanced learning on the verbal portion of the training task by 3.65 items. Furthermore, tDCS was shown to enhance near transfer to other untrained WM tasks in comparison with a no-contact control group. These results lend support to the idea that tDCS might bolster training and transfer gains in populations with compromised WM abilities.

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

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    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.

  15. [Transcranial direct current stimulation: new clinical roadmaps for psychiatric research].

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    Heeren, Alexandre; Coussement, Charlotte; Colon, Élisabeth

    Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that has undergone intensive research over the past decade with promising results. tDCS is based on the application of weak, direct current over the scalp, leading to cortical hypo- or hyperpolarization according to the specified parameters. Recent studies have shown that tDCS is able to induce potent changes in cortical excitability as well as to elicit long-lasting modifications in brain activity. Over the last decade, tDCS physiological mechanisms of action have been intensively investigated. This research has given support for the investigation of tDCS applications in a wide range of clinical populations, including patients with post-stroke motor and language deficits, chronic pain, and tinnitus. Recently, its efficacy to treat psychiatric conditions has been explored increasingly. In this review, we will gather clinical studies involving tDCS to ameliorate psychiatric symptoms and discuss reasonable next steps in this direction. © 2016 médecine/sciences – Inserm.

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

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    Hauser, Tobias U; Rotzer, Stephanie; Grabner, Roland H; Mérillat, Susan; Jäncke, Lutz

    2013-01-01

    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.

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

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    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

  18. 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

  19. Subcortical structures in humans can be facilitated by transcranial direct current stimulation.

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    Jorik Nonnekes

    Full Text Available Transcranial direct current stimulation (tDCS is a noninvasive brain stimulation technique that alters cortical excitability. Interestingly, in recent animal studies facilitatory effects of tDCS have also been observed on subcortical structures. Here, we sought to provide evidence for the potential of tDCS to facilitate subcortical structures in humans as well. Subjects received anodal-tDCS and sham-tDCS on two separate testing days in a counterbalanced order. After stimulation, we assessed the effect of tDCS on two responses that arise from subcortical structures; (1 wrist and ankle responses to an imperative stimulus combined with a startling acoustic stimulus (SAS, and (2 automatic postural responses to external balance perturbations with and without a concurrent SAS. During all tasks, response onsets were significantly faster following anodal-tDCS compared to sham-tDCS, both in trials with and without a SAS. The effect of tDCS was similar for the dominant and non-dominant leg. The SAS accelerated the onsets of ankle and wrist movements and the responses to backward, but not forward perturbations. The faster onsets of SAS-induced wrist and ankle movements and automatic postural responses following stimulation provide strong evidence that, in humans, subcortical structures--in particular the reticular formation--can be facilitated by tDCS. This effect may be explained by two mechanisms that are not mutually exclusive. First, subcortical facilitation may have resulted from enhanced cortico-reticular drive. Second, the applied current may have directly stimulated the reticular formation. Strengthening reticulospinal output by tDCS may be of interest to neurorehabilitation, as there is evidence for reticulospinal compensation after corticospinal lesions.

  20. Long-Lasting Enhancement of Visual Perception with Repetitive Noninvasive Transcranial Direct Current Stimulation

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    Janina R. Behrens

    2017-08-01

    Full Text Available Understanding processes performed by an intact visual cortex as the basis for developing methods that enhance or restore visual perception is of great interest to both researchers and medical practitioners. Here, we explore whether contrast sensitivity, a main function of the primary visual cortex (V1, can be improved in healthy subjects by repetitive, noninvasive anodal transcranial direct current stimulation (tDCS. Contrast perception was measured via threshold perimetry directly before and after intervention (tDCS or sham stimulation on each day over 5 consecutive days (24 subjects, double-blind study. tDCS improved contrast sensitivity from the second day onwards, with significant effects lasting 24 h. After the last stimulation on day 5, the anodal group showed a significantly greater improvement in contrast perception than the sham group (23 vs. 5%. We found significant long-term effects in only the central 2–4° of the visual field 4 weeks after the last stimulation. We suspect a combination of two factors contributes to these lasting effects. First, the V1 area that represents the central retina was located closer to the polarization electrode, resulting in higher current density. Second, the central visual field is represented by a larger cortical area relative to the peripheral visual field (cortical magnification. This is the first study showing that tDCS over V1 enhances contrast perception in healthy subjects for several weeks. This study contributes to the investigation of the causal relationship between the external modulation of neuronal membrane potential and behavior (in our case, visual perception. Because the vast majority of human studies only show temporary effects after single tDCS sessions targeting the visual system, our study underpins the potential for lasting effects of repetitive tDCS-induced modulation of neuronal excitability.

  1. Modulation of cortical activity by transcranial direct current stimulation in patients with affective disorder.

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    Tamara Y Powell

    Full Text Available Transcranial direct current stimulation (tDCS has been shown to have antidepressant efficacy in patients experiencing a major depressive episode, but little is known about the underlying neurophysiology. The purpose of our study was to investigate the acute effects of tDCS on cortical activity using electroencephalography (EEG in patients with an affective disorder. Eighteen patients diagnosed with an affective disorder and experiencing a depressive episode participated in a sham-controlled study of tDCS, each receiving a session of active (2 mA for 20 minutes and sham tDCS to the left dorsolateral prefrontal cortex (DLPFC. The effects of tDCS on EEG activity were assessed after each session using event-related potentials (ERP and measurement of spectral activity during a visual working memory (VWM task. We observed task and intervention dependent effects on both ERPs and task-related alpha and theta activity, where active compared to sham stimulation resulted in a significant reduction in the N2 amplitude and reduced theta activity over frontal areas during memory retrieval. In summary a single session of anodal tDCS stimulation to the left DLPFC during a major depressive episode resulted in modulated brain activity evident in task-related EEG. Effects on the N2 and frontal theta activity likely reflect modulated activity in the medial frontal cortex and hence indicate that the after-effects of tDCS extend beyond the direct focal effects to the left DLPFC.

  2. Comments on: “Transcranial Direct Current Stimulation for Obsessive-Compulsive Disorder: A Systematic Review”

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    Mohammad Alwardat

    2018-03-01

    Full Text Available Dear Editor, Brunelin et al. [1] recently conducted a systematic review that evaluated the effect of applied transcranial direct current stimulation (tDCS on patients with obsessive compulsive disorder (OCD.[...

  3. Transcranial Direct Current Stimulation: Considerations for Research in Adolescent Depression

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    Jonathan C. Lee

    2017-06-01

    Full Text Available Adolescent depression is a prevalent disorder with substantial morbidity and mortality. Current treatment interventions do not target relevant pathophysiology and are frequently ineffective, thereby leading to a substantial burden for individuals, families, and society. During adolescence, the prefrontal cortex undergoes extensive structural and functional changes. Recent work suggests that frontolimbic development in depressed adolescents is delayed or aberrant. The judicious application of non-invasive brain stimulation techniques to the prefrontal cortex may present a promising opportunity for durable interventions in adolescent depression. Transcranial direct current stimulation (tDCS applies a low-intensity, continuous current that alters cortical excitability. While this modality does not elicit action potentials, it is thought to manipulate neuronal activity and neuroplasticity. Specifically, tDCS may modulate N-methyl-d-aspartate receptors and L-type voltage-gated calcium channels and effect changes through long-term potentiation or long-term depression-like mechanisms. This mini-review considers the neurobiological rationale for developing tDCS protocols in adolescent depression, reviews existing work in adult mood disorders, surveys the existing tDCS literature in adolescent populations, reviews safety studies, and discusses distinct ethical considerations in work with adolescents.

  4. Cerebellar transcranial direct current stimulation modulates verbal working memory.

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    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.

  5. Keep calm and carry on: improved frustration tolerance and processing speed by transcranial direct current stimulation (tDCS.

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    Christian Plewnia

    Full Text Available Cognitive control (CC of attention is a major prerequisite for effective information processing. Emotional distractors can bias and impair goal-directed deployment of attentional resources. Frustration-induced negative affect and cognition can act as internal distractors with negative impact on task performance. Consolidation of CC may thus support task-oriented behavior under challenging conditions. Recently, transcranial direct current stimulation (tDCS has been put forward as an effective tool to modulate CC. Particularly, anodal, activity enhancing tDCS to the left dorsolateral prefrontal cortex (dlPFC can increase insufficient CC in depression as indicated by a reduction of attentional biases induced by emotionally salient stimuli. With this study, we provide first evidence that, compared to sham stimulation, tDCS to the left dlPFC enhances processing speed measured by an adaptive version of the Paced Auditory Serial Addition Task (PASAT that is typically thwarted by frustration. Notably, despite an even larger amount of error-related negative feedback, the task-induced upset was suppressed in the group receiving anodal tDCS. Moreover, inhibition of task-related negative affect was correlated with performance gains, suggesting a close link between enhanced processing speed and consolidation of CC by tDCS. Together, these data provide first evidence that activity enhancing anodal tDCS to the left dlPFC can support focused cognitive processing particularly when challenged by frustration-induced negative affect.

  6. Keep calm and carry on: improved frustration tolerance and processing speed by transcranial direct current stimulation (tDCS).

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    Plewnia, Christian; Schroeder, Philipp A; Kunze, Roland; Faehling, Florian; Wolkenstein, Larissa

    2015-01-01

    Cognitive control (CC) of attention is a major prerequisite for effective information processing. Emotional distractors can bias and impair goal-directed deployment of attentional resources. Frustration-induced negative affect and cognition can act as internal distractors with negative impact on task performance. Consolidation of CC may thus support task-oriented behavior under challenging conditions. Recently, transcranial direct current stimulation (tDCS) has been put forward as an effective tool to modulate CC. Particularly, anodal, activity enhancing tDCS to the left dorsolateral prefrontal cortex (dlPFC) can increase insufficient CC in depression as indicated by a reduction of attentional biases induced by emotionally salient stimuli. With this study, we provide first evidence that, compared to sham stimulation, tDCS to the left dlPFC enhances processing speed measured by an adaptive version of the Paced Auditory Serial Addition Task (PASAT) that is typically thwarted by frustration. Notably, despite an even larger amount of error-related negative feedback, the task-induced upset was suppressed in the group receiving anodal tDCS. Moreover, inhibition of task-related negative affect was correlated with performance gains, suggesting a close link between enhanced processing speed and consolidation of CC by tDCS. Together, these data provide first evidence that activity enhancing anodal tDCS to the left dlPFC can support focused cognitive processing particularly when challenged by frustration-induced negative affect.

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

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    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.

  8. Polarity-Specific Transcranial Direct Current Stimulation Disrupts Auditory Pitch Learning

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    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.

  9. Shaping pseudoneglect with transcranial cerebellar direct current stimulation and music listening

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    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.

  10. Shaping pseudoneglect with transcranial cerebellar direct current stimulation and music listening.

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    Picazio, Silvia; Granata, Chiara; Caltagirone, Carlo; Petrosini, Laura; Oliveri, Massimiliano

    2015-01-01

    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.

  11. Effect of transcranial direct current stimulation on swallowing apraxia and cortical excitability in stroke patients.

    Science.gov (United States)

    Yuan, Ying; Wang, Jie; Wu, Dongyu; Huang, Xiaobo; Song, Weiqun

    2017-10-01

    Swallowing apraxia is characterized by impaired volitional swallowing but relatively preserved reflexive swallowing. Few studies are available on the effectiveness of behavioral therapy and management of the condition. This study aimed to investigate the effect of transcranial direct current stimulation (tDCS) on swallowing apraxia and cortical activation in stroke patients. The study included three inpatients (age 48-70 years; 1 male, 2 females; duration of stroke, 35-55 d) with post-stroke swallowing apraxia and six age-matched healthy subjects (age 45-65 years; 3 males, 3 females). Treatments were divided into two phases: Phase A and Phase B. During Phase A, the inpatients received three weeks of sham tDCS and conventional treatments. During Phase B, these patients received three weeks of anodal tDCS over the bilateral primary sensorimotor cortex (S 1 M 1 ) of swallowing and conventional treatments. Swallowing apraxia assessments were measured in three inpatients before Phase A, before Phase B, and after Phase B. The electroencephalography (EEG) nonlinear index of approximate entropy (ApEn) was calculated for three patients and six healthy subjects. After tDCS, scores of swallowing apraxia assessments increased, and ApEn indices increased in both stimulated and non-stimulated areas. Anodal tDCS might provide a useful means for recovering swallowing apraxia, and the recovery could be related to increased excitability of the swallowing cortex. Further investigations should explore the relationship between lesion size and/or lesion site and the prognosis of swallowing apraxia. Clinical trial registry: http://www.chictr.org Registration Number: ChiCTR-TRC-14004955.

  12. Semantic Feature Training in Combination with Transcranial Direct Current Stimulation (tDCS for Progressive Anomia

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    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.

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

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    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.

  14. Intensity, Duration, and Location of High-Definition Transcranial Direct Current Stimulation for Tinnitus Relief.

    Science.gov (United States)

    Shekhawat, Giriraj Singh; Sundram, Frederick; Bikson, Marom; Truong, Dennis; De Ridder, Dirk; Stinear, Cathy M; Welch, David; Searchfield, Grant D

    2016-05-01

    Tinnitus is the perception of a phantom sound. The aim of this study was to compare current intensity (center anode 1 mA and 2 mA), duration (10 minutes and 20 minutes), and location (left temporoparietal area [LTA] and dorsolateral prefrontal cortex [DLPFC]) using 4 × 1 high-definition transcranial direct current stimulation (HD-tDCS) for tinnitus reduction. Twenty-seven participants with chronic tinnitus (>2 years) and mean age of 53.5 years underwent 2 sessions of HD-tDCS of the LTA and DLPFC in a randomized order with a 1 week gap between site of stimulation. During each session, a combination of 4 different settings were used in increasing dose (1 mA, 10 minutes; 1 mA, 20 minutes; 2 mA, 10 minutes; and 2 mA, 20 minutes). The impact of different settings on tinnitus loudness and annoyance was documented. Twenty-one participants (77.78%) reported a minimum of 1 point reduction on tinnitus loudness or annoyance scales. There were significant changes in loudness and annoyance for duration of stimulation,F(1, 26) = 10.08,Ptinnitus relief. The stimulation of the LTA and DLPFC were equally effective for suppressing tinnitus loudness and annoyance. © The Author(s) 2015.

  15. 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 binge eat in men on the day of real tDCS administration (p eating less frequently for reward motives, and greater intent to restrict calories, respectively. This proof of concept study is the first to find ameliorating effects of 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.

  16. Modulation of executive control in dual tasks with transcranial direct current stimulation (tDCS).

    Science.gov (United States)

    Strobach, Tilo; Soutschek, Alexander; Antonenko, Daria; Flöel, Agnes; Schubert, Torsten

    2015-02-01

    Executive processing in dual tasks is primarily associated with activation of the lateral prefrontal cortex (lPFC), which is demonstrated in functional imaging studies (e.g., Szameitat et al., 2006). However, a causal relation between lPFC activity and executive functions in dual tasks has not been demonstrated so far. Here, we used anodal transcranial direct current stimulation (atDCS [1 mA, 20 min] vs. sham stimulation [1 mA, 30s]) over the left inferior frontal junction under conditions of random and fixed task order in dual tasks as well as in single tasks in healthy young individuals (Experiment 1). We found that atDCS, if administered simultaneously to the task, improved performance in random-order dual tasks, but not in fixed-order dual tasks and single tasks. Moreover, dual-task performance under random-order conditions did not improve if atDCS was applied prior to the task performance. The identical procedure in Experiment 2 showed no difference in dual-task performance under random-task order conditions when we compared cathodal tDCS (ctDCS) with sham stimulation. Our findings suggest that dual-task performance is causally related to lPFC activation under conditions that require task-order decisions and high demands on executive functioning. Subsequent studies may now explore if atDCS leads to sustained improvements parallel to the training of dual tasks. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Cerebellar Transcranial Direct Current Stimulation (ctDCS) Impairs Balance Control in Healthy Individuals.

    Science.gov (United States)

    Foerster, Águida; Melo, Lorena; Mello, Marina; Castro, Rebeca; Shirahige, Lívia; Rocha, Sérgio; Monte-Silva, Kátia

    2017-08-01

    The cerebellum plays an important role in the planning, initiation and stability of movements, as well as in postural control and balance. Modulation of neural regions underlying balance control may be a potential alternative to treat balance impairments in cerebellar patients. Transcranial direct current stimulation (tDCS) is a noninvasive and safe tool capable to modulate cerebellar activity. We aim to investigate the effects of cerebellar tDCS (ctDCS) on postural balance in healthy individuals. Fifteen healthy and right-handed subjects were submitted to three sessions of ctDCS (anodal, cathodal and sham), separated by at least 48 h. In each session, tests of static (right and left Athlete Single Leg tests) and dynamic balance (Limits of Stability test) were performed using the Biodex Balance System before and immediately after the ctDCS. The results revealed that cathodal ctDCS impaired static balance of healthy individuals, reflected in higher scores on overall stability index when compared to baseline for right (p = 0.034) and left (p = 0.01) Athlete Single Leg test. In addition, we found significant impairment for left Athlete Single Leg test in comparison to sham stimulation (p = 0.04). As far as we know, this is the first study that points changes on balance control after ctDCS in healthy individuals. This finding raises insights to further investigation about cerebellar modulation for neurological patients.

  18. Novel methods to optimize the effects of transcranial direct current stimulation: a systematic review of transcranial direct current stimulation patents.

    Science.gov (United States)

    Malavera, Alejandra; Vasquez, Alejandra; Fregni, Felipe

    2015-01-01

    Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that has been extensively studied. While there have been initial positive results in some clinical trials, there is still variability in tDCS results. The aim of this article is to review and discuss patents assessing novel methods to optimize the use of tDCS. A systematic review was performed using Google patents database with tDCS as the main technique, with patents filling date between 2010 and 2015. Twenty-two patents met our inclusion criteria. These patents attempt to address current tDCS limitations. Only a few of them have been investigated in clinical trials (i.e., high-definition tDCS), and indeed most of them have not been tested before in human trials. Further clinical testing is required to assess which patents are more likely to optimize the effects of tDCS. We discuss the potential optimization of tDCS based on these patents and the current experience with standard tDCS.

  19. Improvement in direct methanol fuel cell performance by treating the anode at high anodic potential

    Science.gov (United States)

    Joghee, Prabhuram; Pylypenko, Svitlana; Wood, Kevin; Corpuz, April; Bender, Guido; Dinh, Huyen N.; O'Hayre, Ryan

    2014-01-01

    This work investigates the effect of a high anodic potential treatment protocol on the performance of a direct methanol fuel cell (DMFC). DMFC membrane electrode assemblies (MEAs) with PtRu/C (Hi-spec 5000) anode catalyst are subjected to anodic treatment (AT) at 0.8 V vs. DHE using potentiostatic method. Despite causing a slight decrease in the electrochemical surface area (ECSA) of the anode, associated with ruthenium dissolution, AT results in significant improvement in DMFC performance in the ohmic and mass transfer regions and increases the maximum power density by ∼15%. Furthermore, AT improves the long-term DMFC stability by reducing the degradation of the anode catalyst. From XPS investigation, it is hypothesized that the improved performance of AT-treated MEAs is related to an improved interface between the catalyst and Nafion ionomer. Among potential explanations, this improvement may be caused by incorporation of the ionomer within the secondary pores of PtRu/C agglomerates, which generates a percolating network of ionomer between PtRu/C agglomerates in the catalyst layer. Furthermore, the decreased concentration of hydrophobic CF2 groups may help to enhance the hydrophilicity of the catalyst layer, thereby increasing the accessibility of methanol and resulting in better performance in the high current density region.

  20. Induction of visual dream reports after transcranial direct current stimulation (tDCs) during Stage 2 sleep.

    Science.gov (United States)

    Jakobson, Antonia J; Fitzgerald, Paul B; Conduit, Russell

    2012-08-01

    REM sleep is a unique brain state characterized by frontal deactivation alongside activation of the posterior association and limbic cortices. Human brain lesion studies have found that the loss of dreaming is characterized by damage to the frontal and posterior parieto-temporo-occipital association cortex. Therefore, it is reasonable to assume that the function of these brain regions might encapsulate the neural processes of dreaming. The aim of the following two experiments was to investigate the effect of transcranial direct current stimulation (tDCs), applied simultaneously to the frontal and right posterior parietal cortex during Stage 2 sleep, on dreaming. In Experiment 1, 17 healthy participants received tDCs (cathodal-frontal, anodal-parietal) and low-intensity tDCs as well as no tDCs (blank control) during Stage 2 sleep in a counterbalanced order across the night. Dream reports were collected upon awakening after each of the three conditions. In Experiment 2, 10 participants received tDCs (cathodal-frontal, anodal-parietal), no tDCs (blank control) and two additional control conditions (reversed polarity and other-cephalic tDCs). In both experiments a significantly greater number of imagery reports were found on awakening after tDCs (cathodal-frontal, anodal-parietal), compared to the blank control conditions. However, in Experiment 2 the frequency of imagery reports from the tDCs (cathodal-frontal, anodal-parietal) was not significantly different from the other two tDC conditions, suggesting a non-specific effect of tDCs. Overall, it was concluded that tDCs (cathodal-frontal, anodal-parietal) increased the frequency of dream reports with visual imagery, possibly via a general arousing effect and/or recreating specific cortical neural activity involved in dreaming. © 2012 European Sleep Research Society.

  1. Modulation of risky choices in recently abstinent dependent cocaine users: a transcranial direct-current stimulation (tDCS study

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    Alessandra eGorini

    2014-08-01

    Full Text Available Previous neurobiological and neuropsychological investigations have shown that risk-taking behaviors and addictions share many structural and functional aspects. In particular, both are characterised by an irresistible need to obtain immediate rewards as well as by specific alterations in brain circuits responsible for such behaviors.In this study, we used a transcranial direct-current stimulation (tDCS over the dorsolateral prefrontal cortex (DLPFC of two samples of subjects (18 dependent cocaine users and 18 control subjects to investigate the effects of left and right cortical excitability on two risk tasks: the Balloon Analog Risk Task (BART and the Game of Dice Task (GDT. All subjects randomly received a left anodal/right cathodal stimulation (LAn+, a right anodal/left cathodal stimulation (RAn+, and a sham (placebo stimulation each run at least 48 hours apart. Participants were asked to perform the BART and the GDT immediately before and after each stimulation.Our results reveal that the activation of the DLPFC (left and right results in a reduction of risky behaviors at the BART task both in controls subjects and cocaine dependent users. The effect of dTCS on GDT, instead, is more complex. Cocaine users increased safe behavior after right DLPFC anodal stimulation, while risk-taking behavior increased after left DLPFC anodal stimulation. Control subjects’ performance were only affected by the anodal stimulation of the right DLPFC, resulting in an increase of safe bets. These results support the hypothesis that excessive risk propensity in dependent cocaine users, might be due to a hypoactivation of the right DLPFC, as well as to an unbalance interhemispheres interaction. In conclusion, since risky decision-making seems to be, at least in part, responsible for maintenance and relapse of addiction, we argue that a neuromodulation-based approach could represent a valuable adjunct in the clinical treatment of addiction.

  2. 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.

  3. Controlling the Anchoring Effect through Transcranial Direct Current Stimulation (tDCS to the Right Dorsolateral Prefrontal Cortex

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    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.

  4. 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.

  5. Impact of transcranial direct current stimulation on somatosensory transfer learning: when the secondary somatosensory cortex comes into play.

    Science.gov (United States)

    Hirtz, Raphael; Weiss, Thomas; Huonker, Ralph; Witte, Otto W

    2018-04-03

    Transfer learning is an immanent feature of perceptual learning. Yet, despite the increasingly widespread application of transcranial direct current stimulation (tDCS) to study learning, transfer effects in response to tDCS have not been studied. Therefore, the present study investigated the transfer of tactile acuity evoked by repeatedly applied anodal tDCS over the left primary somatosensory cortex (S1) over the course of five days from the dominant (right) to the non-dominant (left) index finger (IF). There was a complete transfer of improvement of the right IF to its contralateral homologue by follow-up four weeks later. Changes in tactile acuity of the left IF in the tDCS anodal condition were accompanied by a significant longitudinal change in functional connectivity between the left S1 and the right secondary somatosensory cortex (S2) assessed at day five of tDCS delivery and four week later. Moreover, we observed a close link between tactile acuity and (changes of) functional connectivity of the right S2 in the tDCS anodal condition identifying the S2 as neural correlate to mediate the transfer of tDCS effects in the somatosensory domain. These findings provide unprecedented evidence of transfer effects evoked by tDCS, implicate the S2 in somatosensory transfer learning and provide evidence in support of models of perceptual learning allocating learning to the reweighting of connections between different levels of processing. Copyright © 2018. Published by Elsevier B.V.

  6. Transcranial direct current stimulation (tDCS of the frontal eye fields during pro- and antisaccade tasks

    Directory of Open Access Journals (Sweden)

    Ryota eKanai

    2012-05-01

    Full Text Available Transcranial direct current stimulation (tDCS has been successfully applied to cortical areas such as the motor cortex and visual cortex. In the present study, we examined whether tDCS can reach and selectively modulate the excitability of the frontal eye field (FEF. In order to assess potential effects of tDCS, we measured saccade latency, landing point and its variability in a simple prosaccade task and in an antisaccade task. In the prosaccade task, we found that anodal tDCS shortened the latency of saccades to a contralateral visual cue. However, cathodal tDCS did not show a significant modulation of saccade latency. In the antisaccade task, on the other hand, we found that the latency for ipisilateral antisaccades was prolonged during the stimulation, whereas anodal stimulation did not modulate the latency of antisaccades. In addition, anodal tDCS reduced the erroneous saccades towards the contralateral visual cue. These results in the antisaccade task suggest that tDCS modulates the function of FEF to suppress reflexive saccades to the contralateral visual cue. Both in the prosaccade and antisaccade tasks, we did not find any effect of tDCS on saccade landing point or its variability. Our present study is the first to show effects of tDCS over FEF and opens the possibility of applying tDCS for studying the functions of FEF in oculomotor and attentional performance.

  7. Transcranial direct current stimulation over multiple days improves learning and maintenance of a novel vocabulary.

    Science.gov (United States)

    Meinzer, Marcus; Jähnigen, Sophia; Copland, David A; Darkow, Robert; Grittner, Ulrike; Avirame, Keren; Rodriguez, Amy D; Lindenberg, Robert; Flöel, Agnes

    2014-01-01

    Recently, growing interest emerged in the enhancement of human potential by means of non-invasive brain stimulation. In particular, anodal transcranial direct current stimulation (atDCS) has been shown to exert beneficial effects on motor and higher cognitive functions. However, the majority of transcranial direct current stimulation (tDCS) studies have assessed effects of single stimulation sessions that are mediated by transient neural modulation. Studies assessing the impact of multiple stimulation sessions on learning that may induce long-lasting behavioural and neural changes are scarce and have not yet been accomplished in the language domain in healthy individuals. The present study probed the potential of atDCS to enhance language learning over multiple days by employing an explicit word learning paradigm. Forty healthy young participants were randomized to learning with either simultaneous atDCS or sham stimulation (N = 20/group; comparable regarding demographic variables and neurocognitive status). All participants acquired a novel vocabulary (familiar and novel object picture - non-word pairs) over five consecutive days. Two memory tasks (free recall; forced choice recognition tasks) were administered immediately after each training session. A one week follow-up tested the maintenance of learning success. Linear mixed effects model analysis revealed superior learning during atDCS compared to sham stimulation for both familiar and novel objects. atDCS yielded a steeper learning curve and significantly more pronounced learning at the end of the training during the recall task. During the recognition task, the atDCS group reached ceiling levels earlier and overall learning success was greater. For both tasks, beneficial atDCS effects were maintained during the follow-up assessment. The present study provides direct evidence that atDCS administered during multiple learning sessions facilitates language learning and that effects are maintained over time

  8. A transcranial direct current stimulation over the sensorimotor cortex modulates the itch sensation induced by histamine.

    Science.gov (United States)

    Nakagawa, Kei; Mochizuki, Hideki; Koyama, Soichiro; Tanaka, Satoshi; Sadato, Norihiro; Kakigi, Ryusuke

    2016-01-01

    Itching can be suppressed by scratching. However, scratching may aggravate itch symptoms by damaging the skin. Therefore, identifying an alternative approach to suppress itching is of clinical importance. The aim of the present study was to determine whether a transcranial direct current stimulation (tDCS) was useful for itch relief. The present study was performed on a double-blind, Sham-controlled, and cross-over experimental design. A histamine-induced itch was evoked on the left dorsal forearms of healthy participants, who were asked to report the subjective sensation of itching every 30s for 23 min. tDCS was applied over the sensorimotor cortex (SMC) according to a bi-hemispheric stimulation protocol during the itch stimuli; one electrode was placed over the right SMC, while the other was placed over the left SMC. The peak and lasting sensations of itching were compared between R-A/L-C (anodal electrode placed over the right and cathodal electrode over the left), L-A/R-C (anodal electrode placed over the left and cathodal electrode over the right), and Sham interventions. The peak and lasting itch sensation were significantly suppressed during the R-A/L-C intervention than during the Sham intervention. On the other hand, the L-A/R-C intervention suppressed the peak itch sensation, but the effects did not last for more than a few minutes. These results suggest that a bi-hemispheric tDCS intervention, especially when the anodal electrode was placed over the SMC of the contralateral side, was a potentially useful method for relieving lasting itch sensations. The present study demonstrated that a tDCS intervention may be an alternative approach for suppressing unpleasant itch sensations in healthy participants. Since tDCS has some advantages, namely, its easy application and safety in a clinical setting, it may become a useful method for the treatment of itching. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland

  9. 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...... electrode. Importantly, dual-hemisphere tDCS with the anodal electrode over the left PO yielded a decreased threshold in the right finger compared with the uni-hemisphere tDCS condition. These results suggest that the ipsilateral PO inhibits tactile processing of grating orientation, indicating...

  10. 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...... 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......-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...

  11. Modelling the effect of electrode displacement on transcranial direct current stimulation (tDCS)

    Science.gov (United States)

    Ramaraju, Sriharsha; Roula, Mohammed A.; McCarthy, Peter W.

    2018-02-01

    Objective. Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers a low-intensity, direct current to cortical areas with the purpose of modulating underlying brain activity. Recent studies have reported inconsistencies in tDCS outcomes. The underlying assumption of many tDCS studies has been that replication of electrode montage equates to replicating stimulation conditions. It is possible however that anatomical difference between subjects, as well as inherent inaccuracies in montage placement, could affect current flow to targeted areas. The hypothesis that stimulation of a defined brain region will be stable under small displacements was tested. Approach. Initially, we compared the total simulated current flowing through ten specific brain areas for four commonly used tDCS montages: F3-Fp2, C3-Fp2, Fp1-F4, and P3-P4 using the software tool COMETS. The effect of a slight (~1 cm in each of four directions) anode displacement on the simulated regional current density for each of the four tDCS montages was then determined. Current flow was calculated and compared through ten segmented brain areas to determine the effect of montage type and displacement. The regional currents, as well as the localised current densities, were compared with the original electrode location, for each of these new positions. Main results. Recommendations for montages that maximise stimulation current for the ten brain regions are considered. We noted that the extent to which stimulation is affected by electrode displacement varies depending on both area and montage type. The F3-Fp2 montage was found to be the least stable with up to 38% change in average current density in the left frontal lobe while the Fp1-F4 montage was found to the most stable exhibiting only 1% change when electrodes were displaced. Significance. These results indicate that even relatively small changes in stimulation electrode placement appear to result in surprisingly large

  12. Transcranial direct current stimulation improves the QT variability index and autonomic cardiac control in healthy subjects older than 60 years

    Directory of Open Access Journals (Sweden)

    Piccirillo G

    2016-11-01

    Full Text Available Gianfranco Piccirillo,1 Cristina Ottaviani,2 Claudia Fiorucci,1 Nicola Petrocchi,2 Federica Moscucci,1 Claudia Di Iorio,1 Fabiola Mastropietri,1 Ilaria Parrotta,1 Matteo Pascucci,1 Damiano Magrì3 1Department of Cardiovascular, Respiratory, Nephrological, Anestesiological and Geriatric Sciences, “Sapienza” University, 2Neuroimaging Laboratory, IRCCS Santa Lucia Foundation, 3Department of Clinical and Molecular Medicine, University of Rome “Sapienza”, Rome, Italy Background: Noninvasive brain stimulation technique is an interesting tool to investigate the causal relation between cortical functioning and autonomic nervous system (ANS responses. Objective: The objective of this report is to evaluate whether anodal transcranial direct current stimulation (tDCS over the temporal cortex influences short-period temporal ventricular repolarization dispersion and cardiovascular ANS control in elderly subjects. Subjects and methods: In 50 healthy subjects (29 subjects younger than 60 years and 21 subjects older than 60 years matched for gender, short-period RR and systolic blood pressure spectral variability, QT variability index (QTVI, and noninvasive hemodynamic data were obtained during anodal tDCS or sham stimulation. Results: In the older group, the QTVI, low-frequency (LF power expressed in normalized units, the ratio between LF and high-frequency (HF power, and systemic peripheral resistances decreased, whereas HF power expressed in normalized units and α HF power increased during the active compared to the sham condition (P<0.05. Conclusion: In healthy subjects older than 60 years, tDCS elicits cardiovascular and autonomic changes. Particularly, it improves temporal ventricular repolarization dispersion, reduces sinus sympathetic activity and systemic peripheral resistance, and increases vagal sinus activity and baroreflex sensitivity. Keywords: transcranial direct current stimulation, QT variability, heart rate variability

  13. Can transcranial direct current stimulation be useful in differentiating unresponsive wakefulness syndrome from minimally conscious state patients?

    Science.gov (United States)

    Naro, Antonino; Calabrò, Rocco Salvatore; Russo, Margherita; Leo, Antonino; Pollicino, Patrizia; Quartarone, Angelo; Bramanti, Placido

    2015-01-01

    Disorders of consciousness (DOC) diagnosis relies on the presence or absence of purposeful motor responsiveness, which characterizes the minimally conscious state (MCS) and the unresponsive wakefulness syndrome (UWS), respectively. Functional neuroimaging studies have raised the question of possible residual conscious awareness also in clinically-defined UWS patients. The aim of our study was to identify electrophysiological parameters, by means of a transcranial magnetic stimulation approach, which might potentially express the presence of residual networks sustaining fragmentary behavioral patterns, even when no conscious behavior can be observed. We enrolled 25 severe DOC patients, following post-anoxic or traumatic brain injury and 20 healthy individuals (HC) as control group. Baseline electrophysiological evaluation evidenced, in comparison to HC, a partial preservation of cortical effective connectivity and excitability in clinically defined MCS, whereas these components were absent in clinically defined UWS. Then, we applied an anodal transcranial direct current stimulation (a-tDCS) protocol over the orbitofrontal cortex. a-tDCS was able to boost cortical connectivity and excitability in all HC, MCS, and to unmask such excitability/connectivity in some UWS patients. a-tDCS could be useful in identifying residual connectivity markers in clinically-defined UWS, who may lack of purposeful behavior as a result of a motor-output failure.

  14. Improved Anode for a Direct Methanol Fuel Cell

    Science.gov (United States)

    Valdez, Thomas; Narayanan, Sekharipuram

    2005-01-01

    A modified chemical composition has been devised to improve the performance of the anode of a direct methanol fuel cell. The main feature of the modified composition is the incorporation of hydrous ruthenium oxide into the anode structure. This modification can reduce the internal electrical resistance of the cell and increase the degree of utilization of the anode catalyst. As a result, a higher anode current density can be sustained with a smaller amount of anode catalyst. These improvements can translate into a smaller fuel-cell system and higher efficiency of conversion. Some background information is helpful for understanding the benefit afforded by the addition of hydrous ruthenium oxide. The anode of a direct methanol fuel cell sustains the electro-oxidation of methanol to carbon dioxide in the reaction CH3OH + H2O--->CO2 + 6H(+) + 6e(-). An electrocatalyst is needed to enable this reaction to occur. The catalyst that offers the highest activity is an alloy of approximately equal numbers of atoms of the noble metals platinum and ruthenium. The anode is made of a composite material that includes high-surface-area Pt/Ru alloy particles and a proton-conducting ionomeric material. This composite is usually deposited onto a polymer-electrolyte (proton-conducting) membrane and onto an anode gas-diffusion/current-collector sheet that is subsequently bonded to the proton-conducting membrane by hot pressing. Heretofore, the areal density of noble-metal catalyst typically needed for high performance has been about 8 mg/cm2. However, not all of the catalyst has been utilized in the catalyzed electro-oxidation reaction. Increasing the degree of utilization of the catalyst would make it possible to improve the performance of the cell for a given catalyst loading and/or reduce the catalyst loading (thereby reducing the cost of the cell). The use of carbon and possibly other electronic conductors in the catalyst layer has been proposed for increasing the utilization of the

  15. A Randomized Double-Blind Sham-Controlled Study of Transcranial Direct Current Stimulation for Treatment-Resistant Major Depression

    Directory of Open Access Journals (Sweden)

    Daniel eBlumberger

    2012-08-01

    Full Text Available Objectives: Transcranial direct current stimulation (tDCS has demonstrated some efficacy in treatment-resistant major depression (TRD. The majority of previous controlled studies have used anodal stimulation to the left dorsolateral prefrontal cortex (DLPFC and a control location such as the supraorbital region on for the cathode. Several open label studies have suggested effectiveness from anodal stimulation to the left DLPFC combined with cathodal stimulation to the right DLPFC. Thus, this study evaluated the efficacy of tDCS using anodal stimulation to the left DLPFC and cathodal stimulation to the right DLPFC compared to sham tDCS. Methods: Subjects between the ages of 18 and 65 were recruited from a tertiary care university hospital. Twenty-four subjects with TRD and a 17-item Hamilton Depression Rating Scale (HDRS greater than 21 were randomized to receive tDCS or sham tDCS. The rates of remission were compared between the two treatment groups.Results: The remission rates did not differ significantly between the two groups using an intention to treat analysis. More subjects in the active tDCS group had failed a course of electroconvulsive therapy in the current depressive episode. Side effects did not differ between the two groups and in general the treatment was very well tolerated. Conclusion: Anodal stimulation to the left DLPFC and cathodal stimulation to the right DLPFC was not efficacious in TRD. However, a number of methodological limitations warrant caution in generalizing from this study. Ongoing, controlled studies should provide further clarification on the efficacy of this stimulation configuration in TRD.

  16. Transcranial direct current stimulation of the dorsolateral prefrontal cortex modulates repetition suppression to unfamiliar faces: an ERP study.

    Directory of Open Access Journals (Sweden)

    Marc Philippe Lafontaine

    Full Text Available Repeated visual processing of an unfamiliar face suppresses neural activity in face-specific areas of the occipito-temporal cortex. This "repetition suppression" (RS is a primitive mechanism involved in learning of unfamiliar faces, which can be detected through amplitude reduction of the N170 event-related potential (ERP. The dorsolateral prefrontal cortex (DLPFC exerts top-down influence on early visual processing. However, its contribution to N170 RS and learning of unfamiliar faces remains unclear. Transcranial direct current stimulation (tDCS transiently increases or decreases cortical excitability, as a function of polarity. We hypothesized that DLPFC excitability modulation by tDCS would cause polarity-dependent modulations of N170 RS during encoding of unfamiliar faces. tDCS-induced N170 RS enhancement would improve long-term recognition reaction time (RT and/or accuracy rates, whereas N170 RS impairment would compromise recognition ability. Participants underwent three tDCS conditions in random order at ∼72 hour intervals: right anodal/left cathodal, right cathodal/left anodal and sham. Immediately following tDCS conditions, an EEG was recorded during encoding of unfamiliar faces for assessment of P100 and N170 visual ERPs. The P3a component was analyzed to detect prefrontal function modulation. Recognition tasks were administered ∼72 hours following encoding. Results indicate the right anodal/left cathodal condition facilitated N170 RS and induced larger P3a amplitudes, leading to faster recognition RT. Conversely, the right cathodal/left anodal condition caused N170 amplitude and RTs to increase, and a delay in P3a latency. These data demonstrate that DLPFC excitability modulation can influence early visual encoding of unfamiliar faces, highlighting the importance of DLPFC in basic learning mechanisms.

  17. Transcranial direct current stimulation (tDCS) for sleep disturbances and fatigue in patients with post-polio syndrome.

    Science.gov (United States)

    Acler, Michele; Bocci, Tommaso; Valenti, Diana; Turri, Mara; Priori, Alberto; Bertolasi, Laura

    2013-01-01

    Post-polio syndrome develops about 20-40 years after acute paralytic poliomyelitis, and manifests with progressively deteriorating muscle strength and endurance. Here, we assessed whether transcranial direct current stimulation (tDCS) improves sleep and fatigue symptoms in patients with post-polio syndrome. We enrolled 32 patients with a diagnosis of post-polio syndrome. tDCS (1.5 mA, 15 min) was delivered by a direct current stimulator connected to three electrodes: two anodal electrodes on the scalp over the right and left pre-motor cortex and the other above the left shoulder (cathode). 16 patients received anodal tDCS and the remainder sham tDCS. We evaluated changes induced by tDCS (daily for five days a week, for three weeks) on clinical scales (Short Form Health Survey [SF-36], Piper Fatigue Scale [PFS], Fatigue Severity Scale [FSS], 101-Point Numerical Rating [PNR-101], Hamilton Rating Scale for Depression [HRSD], Pittsburgh Sleep Quality Index [PSQI]) at baseline (T0) and three weeks later (T1). At T1 SF-36 sub-items physical functioning, role physical, vitality, social functioning and role emotional improved significantly more in patients who received tDCS (p post-polio syndrome. tDCS could be a non-invasive and valuable new tool for managing post-polio patients.

  18. Subcortical structures in humans can be facilitated by transcranial direct current stimulation

    NARCIS (Netherlands)

    Nonnekes, Johan Hendrik; Arrogi, Anass; Munneke, Moniek; van Asseldonk, Edwin H.F.; Oude Nijhuis, Lars; Geurts, Alexander; Weerdesteyn, Vivian

    2014-01-01

    BACKGROUND: Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability via application of a weak direct current. Interestingly, it was demonstrated in cats that tDCS can facilitate subcortical structures as well (Bolzonii et al., J

  19. The role of early stages of cortical visual processing in size and distance judgment: a transcranial direct current stimulation study.

    Science.gov (United States)

    Costa, Thiago L; Costa, Marcelo F; Magalhães, Adsson; Rêgo, Gabriel G; Nagy, Balázs V; Boggio, Paulo S; Ventura, Dora F

    2015-02-19

    Recent research suggests that V1 plays an active role in the judgment of size and distance. Nevertheless, no research has been performed using direct brain stimulation to address this issue. We used transcranial direct-current stimulation (tDCS) to directly modulate the early stages of cortical visual processing while measuring size and distance perception with a psychophysical scaling method of magnitude estimation in a repeated-measures design. The subjects randomly received anodal, cathodal, and sham tDCS in separate sessions starting with size or distance judgment tasks. Power functions were fit to the size judgment data, whereas logarithmic functions were fit to distance judgment data. Slopes and R(2) were compared with separate repeated-measures analyses of variance with two factors: task (size vs. distance) and tDCS (anodal vs. cathodal vs. sham). Anodal tDCS significantly decreased slopes, apparently interfering with size perception. No effects were found for distance perception. Consistent with previous studies, the results of the size task appeared to reflect a prothetic continuum, whereas the results of the distance task seemed to reflect a metathetic continuum. The differential effects of tDCS on these tasks may support the hypothesis that different physiological mechanisms underlie judgments on these two continua. The results further suggest the complex involvement of the early visual cortex in size judgment tasks that go beyond the simple representation of low-level stimulus properties. This supports predictive coding models and experimental findings that suggest that higher-order visual areas may inhibit incoming information from the early visual cortex through feedback connections when complex tasks are performed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Transcranial direct current stimulation modulates neuronal activity and learning in pilot training

    Directory of Open Access Journals (Sweden)

    Jaehoon eChoe

    2016-02-01

    Full Text Available Skill acquisition requires distributed learning both within (online and across (offline days to consolidate experiences into newly learned abilities. In particular, piloting an aircraft requires skills developed from extensive training and practice. Here, we tested the hypothesis that transcranial direct current stimulation (tDCS can modulate neuronal function to improve skill learning and performance during flight simulator training of aircraft landing procedures. Thirty-two right-handed participants consented to participate in four consecutive daily sessions of flight simulation training and received sham or anodal high-definition-tDCS to the right dorsolateral prefrontal cortex (DLPFC or left motor cortex (M1 in a randomized, double-blind experiment. Continuous electroencephalography (EEG and functional near infrared spectroscopy (fNIRS were collected during flight simulation, n-back working memory, and resting-state assessments. tDCS of the right DLPFC increased midline-frontal theta-band activity in flight and n-back working memory training, confirming tDCS-related modulation of brain processes involved in executive function. This modulation corresponded to a significantly different online and offline learning rates for working memory accuracy and decreased inter-subject behavioral variability in flight and n-back tasks in the DLPFC stimulation group. Additionally, tDCS of left M1 increased parietal alpha power during flight tasks and tDCS to the right DLPFC increased midline frontal theta-band power during n-back and flight tasks. These results demonstrate a modulation of group variance in skill acquisition through an increasing in learned skill consistency in cognitive and real-world tasks with tDCS. Further, tDCS performance improvements corresponded to changes in electrophysiological and blood-oxygenation activity of the DLPFC and motor cortices, providing a stronger link between modulated neuronal function and behavior.

  1. Treatment of primary progressive aphasias by transcranial direct current stimulation combined with language training.

    Science.gov (United States)

    Cotelli, Maria; Manenti, Rosa; Petesi, Michela; Brambilla, Michela; Cosseddu, Maura; Zanetti, Orazio; Miniussi, Carlo; Padovani, Alessandro; Borroni, Barbara

    2014-01-01

    Primary progressive aphasia (PPA) is an untreatable neurodegenerative disorder that disrupts language functions. Previous studies have demonstrated transcranial direct current stimulation (tDCS) may improve language symptoms in patients with post stroke aphasia or neurodegenerative diseases. The present study investigated whether the application of anodal tDCS (AtDCS) to the scalp overlying the left dorsolateral prefrontal cortex (DLPFC), which may increase cortical excitability, in combination with individualized speech therapy would improve naming accuracy in the agrammatic variant of PPA (avPPA). Sixteen avPPA patients were randomly allocated into two subgroups: AtDCS (n = 8) or placebo tDCS (PtDCS). tDCS was applied over the left DLPFC (BA 8/9) 25 minutes per day for two weeks (10 days). Each patient underwent 25 minutes of individualized speech therapy with either AtDCS or PtDCS during each treatment session. Neuropsychological assessment, experimental naming, and linguistic abilities in daily living were assessed at baseline (T0), after two weeks of intervention (T1) and at a 12-week follow-up (T2). Significant improvement in experimental naming was observed in both groups at T1 and T2, but this effect was significantly greater in AtDCS than PtDCS patients. Naming correctness, as assessed using the Aachener Aphasie Test, increased selectively in the AtDCS group from T0 to T1, and this effect remained significant at T2. The analysis of daily living language abilities improved selectively in AtDCS group. Our results support the beneficial effect of targeted language training in combination with brain stimulation in avPPA patients. tDCS should be considered a useful tool for the improvement of language functions in patients with neurodegenerative diseases in future trials.

  2. Effects of Transcranial Direct-Current Stimulation on Neurosurgical Skill Acquisition: A Randomized Controlled Trial.

    Science.gov (United States)

    Ciechanski, Patrick; Cheng, Adam; Lopushinsky, Steven; Hecker, Kent; Gan, Liu Shi; Lang, Stefan; Zareinia, Kourosh; Kirton, Adam

    2017-12-01

    Recent changes in surgical training environments may have limited opportunities for trainees to gain proficiency in skill. Complex skills such as neurosurgery require extended periods of training. Methods to enhance surgical training are required to overcome duty-hour restrictions, to ensure the acquisition of skill proficiency. Transcranial direct-current stimulation (tDCS) can enhance motor skill learning, but is untested in surgical procedural training. We aimed to determine the effects of tDCS on simulation-based neurosurgical skill acquisition. Medical students were trained to acquire tumor resection skills using a virtual reality neurosurgical simulator. The primary outcome of change in tumor resection was scored at baseline, over 8 repetitions, post-training, and again at 6 weeks. Participants received anodal tDCS or sham over the primary motor cortex. Secondary outcomes included changes in brain resected, resection effectiveness, duration of excessive forces (EF) applied, and resection efficiency. Additional outcomes included tDCS tolerability. Twenty-two students consented to participate, with no dropouts over the course of the trial. Participants receiving tDCS intervention increased the amount of tumor resected, increased the effectiveness of resection, reduced the duration of EF applied, and improved resection efficiency. Little or no decay was observed at 6 weeks in both groups. No adverse events were documented, and sensation severity did not differ between stimulation groups. The addition of tDCS to neurosurgical training may enhance skill acquisition in a simulation-based environment. Trials of additional skills in high-skill residents, and translation to nonsimulated performance are needed to determine the potential utility of tDCS in surgical training. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. 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.

  4. Novel Anode Catalyst for Direct Methanol Fuel Cells

    OpenAIRE

    Basri, S.; Kamarudin, S. K.; Daud, W. R. W.; Yaakob, Z.; Kadhum, A. A. H.

    2014-01-01

    PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs) but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni) and iron (Fe). Multiwalled carbon nanotubes (MWCNTs) are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX), X-ray diffracti...

  5. Modulating affective experience and emotional intelligence with loving kindness meditation and transcranial direct current stimulation: A pilot study.

    Science.gov (United States)

    Robinson, Charles; Armenta, Mika; Combs, Angela; Lamphere, Melanie L; Garza, Gabrielle J; Neary, James; Wolfe, Janet H; Molina, Edward; Semey, Dominick E; McKee, Christina M; Gallegos, Stevi J; Jones, Aaron P; Trumbo, Michael C; Al-Azzawi, Hussein; Hunter, Michael A; Lieberman, Gregory; Coffman, Brian A; Aboseria, Mohamed; Bikson, Marom; Clark, Vincent P; Witkiewitz, Katie

    2017-10-31

    Positive emotional perceptions and healthy emotional intelligence (EI) are important for social functioning. In this study, we investigated whether loving kindness meditation (LKM) combined with anodal transcranial direct current stimulation (tDCS) would facilitate improvements in EI and changes in affective experience of visual stimuli. LKM has been shown to increase positive emotional experiences and we hypothesized that tDCS could enhance these effects. Eighty-seven undergraduates were randomly assigned to 30 minutes of LKM or a relaxation control recording with anodal tDCS applied to the left dorsolateral prefrontal cortex (left dlPFC) or right temporoparietal junction (right TPJ) at 0.1 or 2.0 milliamps. The primary outcomes were self-reported affect ratings of images from the International Affective Picture System and EI as measured by the Mayer, Salovey and Caruso Emotional Intelligence Test. Results indicated no effects of training on EI, and no main effects of LKM, electrode placement, or tDCS current strength on affect ratings. There was a significant interaction of electrode placement by meditation condition (p = 0.001), such that those assigned to LKM and right TPJ tDCS, regardless of current strength, rated neutral and positive images more positively after training. Results suggest that LKM may enhance positive affective experience.

  6. Prefronto-Cerebellar Transcranial Direct Current Stimulation Improves Sleep Quality in Euthymic Bipolar Patients: A Brief Report

    Directory of Open Access Journals (Sweden)

    Amedeo Minichino

    2014-01-01

    Full Text Available Introduction. Sleep problems are common in bipolar disorder (BD and may persist during the euthymic phase of the disease. The aim of the study was to improve sleep quality of euthymic BD patients through the administration of prefronto-cerebellar transcranial direct current stimulation (tDCS. Methods. 25 euthymic outpatients with a diagnosis of BD Type I or II have been enrolled in the study. tDCS montage was as follows: cathode on the right cerebellar cortex and anode over the left dorsolateral prefrontal cortex (DLPFC; the intensity of stimulation was set at 2 mA and delivered for 20 min/die for 3 consecutive weeks. The Pittsburgh Sleep Quality Index (PSQI was used to assess sleep quality at baseline and after the tDCS treatment. Results. PSQI total score and all PSQI subdomains, with the exception of “sleep medication,” significantly improved after treatment. Discussion. This is the first study where a positive effect of tDCS on the quality of sleep in euthymic BD patients has been reported. As both prefrontal cortex and cerebellum may play a role in regulating sleep processes, concomitant cathodal (inhibitory stimulation of cerebellum and anodal (excitatory stimulation of DLPFC may have the potential to modulate prefrontal-thalamic-cerebellar circuits leading to improvements of sleep quality.

  7. Improving Naming Abilities among Healthy Young-Old Adults Using Transcranial Direct Current Stimulation

    Science.gov (United States)

    Lifshitz-Ben-Basat, Adi; Mashal, Nira

    2018-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive tool to facilitate brain plasticity and enhance language abilities. Our study aims to search for a potential beneficial influence of tDCS on a cognitive linguistic task of naming which found to decline during aging. A group of fifteen healthy old adults (M = 64.93 ± 5.09 years) were…

  8. Single-layer skull approximations perform well in transcranial direct current stimulation modeling

    NARCIS (Netherlands)

    Rampersad, S.M.; Stegeman, D.F.; Oostendorp, T.F.

    2013-01-01

    In modeling the effect of transcranial direct current stimulation, the representation of the skull is an important factor. In a spherical model, we compared a realistic skull modeling approach, in which the skull consisted of three isotropic layers, to anisotropic and isotropic single-layer

  9. 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...

  10. Subcortical Structures in Humans Can Be Facilitated by Transcranial Direct Current Stimulation

    NARCIS (Netherlands)

    Nonnekes, Johan Hendrik; Arrogi, A.; Munneke, M.A.M.; van Asseldonk, Edwin H.F.; Oude Nijhuis, L.B.; Geurts, A.C.; Weerdesteyn, V.

    2014-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability. Interestingly, in recent animal studies facilitatory effects of tDCS have also been observed on subcortical structures. Here, we sought to provide evidence for the potential

  11. Subcortical structures in humans can be facilitated by transcranial direct current stimulation

    NARCIS (Netherlands)

    Nonnekes, J.H.; Arrogi, A.; Munneke, M.A.M.; Asseldonk, E.H. van; Nijhuis, L.B.; Geurts, A.C.H.; Weerdesteyn, V.G.M.

    2014-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability. Interestingly, in recent animal studies facilitatory effects of tDCS have also been observed on subcortical structures. Here, we sought to provide evidence for the potential

  12. Modulation of cortical activity by transcranial direct current stimulation in patients with affective disorder

    NARCIS (Netherlands)

    Powell, T.Y.; Boonstra, T.W.; Martin, D.M.; Loo, C.K.; Breakspear, M.

    2014-01-01

    Transcranial direct current stimulation (tDCS) has been shown to have antidepressant efficacy in patients experiencing a major depressive episode, but little is known about the underlying neurophysiology. The purpose of our study was to investigate the acute effects of tDCS on cortical activity

  13. A Meta-analysis of Transcranial Direct Current Stimulation Studies Examining the Reliability of Effects on Language Measures.

    Science.gov (United States)

    Price, Amy R; McAdams, Harrison; Grossman, Murray; Hamilton, Roy H

    2015-01-01

    Transcranial direct current stimulation (tDCS) is a brain stimulation technique used to examine causal relationships between brain regions and cognitive functions. The effects from tDCS are complex, and the extent to which stimulation reliably affects different cognitive domains is not fully understood and continues to be debated. To conduct a meta-analysis of studies examining the effects of single-session anodal tDCS on language. The meta-analysis examined the behavioral results from eleven experiments of single-session anodal tDCS and language processing in healthy adults. The means and standard deviations of the outcome measures were extracted from each experiment and entered into the meta-analyses. In the first analysis, we examined the effects of single-session tDCS across all language studies. Next, a series of sub-analyses examined the effects of tDCS on specific tasks and stimulation protocols. There was a significant effect from anodal single-session tDCS in healthy adults compared to sham (P = 0.001) across all language measures. Next, we found significant effects on specific stimulation protocols (e.g., offline measures, P = 0.002), as well as specific tasks and electrode montages (e.g., verbal fluency measures and left prefrontal cortex, P = 0.035). The results indicate that single-session tDCS produces significant and reliable effects on language measures in healthy adults. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. The effect of left frontal transcranial direct-current stimulation on propranolol-induced fear memory acquisition and consolidation deficits.

    Science.gov (United States)

    Nasehi, Mohammad; Khani-Abyaneh, Mozhgan; Ebrahimi-Ghiri, Mohaddeseh; Zarrindast, Mohammad-Reza

    2017-07-28

    Accumulating evidence supports the efficacy of transcranial direct current stimulation (tDCS) in modulating numerous cognitive functions. Despite the fact that tDCS has been used for the enhancement of memory and cognition, very few animal studies have addressed its impact on the modulation of fear memory. This study was designed to determine whether pre/post-training frontal tDCS application would alter fear memory acquisition and/or consolidation deficits induced by propranolol in NMRI mice. Results indicated that administration of β1-adrenoceptor blocker propranolol (0.1mg/kg) impaired fear memory retrieval. Pre/post-training application of anodal tDCS when propranolol was administered prior to training reversed contextual memory retrieval whereas only the anodal application prior to training could induce the same result in the auditory test. Meanwhile, anodal stimulation had no effect on fear memories by itself. Moreover, regardless of when cathode was applied and propranolol administered, their combination restored contextual memory retrieval, while only cathodal stimulation prior to training facilitated the contextual memory retrieval. Also, auditory memory retrieval was restored when cathodal stimulation and propranolol occurred prior to training but it was abolished when stimulation occurred after training and propranolol was administered prior to training. Collectively, our findings show that tDCS applied on the left frontal cortex of mice affects fear memory performance. This alteration seems to be task-dependent and varies depending on the nature and timing of the stimulation. In certain conditions, tDCS reverses the effect of propranolol. These results provide initial evidence to support the timely use of tDCS for the modulation of fear-related memories. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Transcranial direct current stimulation to the parietal cortex in hemispatial neglect: A feasibility study.

    Science.gov (United States)

    Smit, Miranda; Schutter, Dennis J L G; Nijboer, Tanja C W; Visser-Meily, Johanna M A; Kappelle, L Jaap; Kant, Neeltje; Penninx, Janne; Dijkerman, H Chris

    2015-07-01

    Prior research suggests that dampening neural activity of the intact, presumably overactive hemisphere, combined with increasing neural activity in the damaged hemisphere, might restore cortical interhemispheric balance and reduce neglect. In the present study we repeatedly applied a relatively new technique, transcranial direct current stimulation (tDCS), to the posterior parietal cortex to modulate spontaneous neural activity levels in a polarity dependent fashion to find evidence for improvements in severe hemispatial neglect in chronic patients. Eighty-nine patients were initially identified from our databases as having neglect, after thoroughly screening databases, consulting medical practitioners and baseline testing, only five met our inclusion criteria and agreed to participate. Sixty-five patients were excluded as they did not meet safety criteria for tDCS (epilepsy, metal implants), suffered from other medical conditions (i.e., heart disease, epilepsy, current psychiatric disorder) or displayed only mild neglect at baseline testing. Five patients with severe chronic hemispatial neglect were enrolled in a double-blind, placebo-controlled treatment program. TDCS or placebo was applied for 20 minutes over the left (cathodal) and right (anodal) posterior parietal cortex at an intensity of 2 mA on five consecutive days. Treatment conditions were separated by a four week wash-out period. Baseline corrected change in performance on the conventional subtests of the Behavioral Inattention Test (BIT) was our primary endpoint. No treatment-related effects were observed for the BIT change scores and performance on individual subtests. Moreover, patients' performance somewhat improved only during the stimulation period (day one vs day five, irrespective of whether it was placebo or tDCS), but not thirty days later, indicating a practice effect. The present study does not provide evidence that tDCS to the posterior parietal cortex improves chronic hemispatial neglect

  16. Transcranial direct current stimulation combined with upper limb functional training in children with spastic, hemiparetic cerebral palsy: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Moura, Renata Calhes Franco; Santos, Cibele Almeida; Grecco, Luanda André Collange; Lazzari, Roberta Delasta; Dumont, Arislander Jonathan Lopes; Duarte, Natalia Carvalho de Almeida; Braun, Luiz Alfredo; Lopes, Jamile Benite Palma; Santos, Ligia Abram Dos; Rodrigues, Eliane Lopes Souza; Albertini, Giorgio; Cimolin, Veronica; Galli, Manuela; Oliveira, Claudia Santos

    2016-08-17

    The aim of the proposed study is to perform a comparative analysis of functional training effects for the paretic upper limb with and without transcranial direct current stimulation over the primary motor cortex in children with spastic hemiparetic cerebral palsy. The sample will comprise 34 individuals with spastic hemiparetic cerebral palsy, 6 to 16 years old, classified at level I, II, or III of the Manual Ability Classification System. Participants will be randomly allocated to two groups: (1) functional training of the paretic upper limb combined with anodic transcranial stimulation; (2) functional training of the paretic upper limb combined with sham transcranial stimulation. Evaluation will involve three-dimensional movement analysis and electromyography using the SMART-D 140® system (BTS Engineering) and the FREEEMG® system (BTS Engineering), the Quality of Upper Extremity Skills Test, to assess functional mobility, the Portable Device and Ashworth Scale, to measure movement resistance and spasticity, and the Pediatric Evaluation of Disability Inventory, to evaluate performance. Functional reach training of the paretic upper limb will include a range of manual activities using educational toys associated with an induced constraint of the non-paretic limb during the training. Training will be performed in five weekly 20-minute sessions for two weeks. Transcranial stimulation over the primary motor cortex will be performed during the training sessions at an intensity of 1 mA. Findings will be analyzed statistically considering a 5 % significance level (P ≤ 0.05). This paper presents a detailed description of a prospective, randomized, controlled, double-blind, clinical trial designed to demonstrate the effects of combining transcranial direct current stimulation over the primary motor cortex and functional training of the paretic limb in children with cerebral palsy classified at level I, II, or III of the Manual Ability Classification System. The

  17. Parkinson's disease treatments: focus on transcranial direct current stimulation (tDCS

    Directory of Open Access Journals (Sweden)

    Tahtis V

    2017-10-01

    Full Text Available Vassilios Tahtis,1 Diego Kaski1,2 1Division of Brain Sciences, Imperial College London, Charing Cross Hospital Campus, 2Sobell Department for Motor Control and Movement Disorders, University College London, London, UK Abstract: Parkinson’s disease (PD is among the most common progressive neurodegenerative conditions worldwide, characterized by bradykinesia, rigidity, tremor, and postural instability, in addition to a variety of cognitive and behavior complications. Current pharmacological treatment options focus on dopaminergic replacement, but these become less efficacious as the disease progresses. Noninvasive brain stimulation techniques have therefore gained favor in recent years as a means of treating the motor and non-motor complications of PD. Here we review the evidence behind the use of transcranial direct current stimulation in the treatment of motor and non-motor complications of PD, discuss the limitations that have hindered the introduction of transcranial direct current stimulation into mainstream clinical practice, and highlight future directions that may enable the translation of this research tool into clinical use. Keywords: Parkinson’s disease, transcranial direct current stimulation, motor, cognitive, non-motor

  18. 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.

  19. Transient Changes in Brain Metabolites after Transcranial Direct Current Stimulation in Spastic Cerebral Palsy: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Paradee Auvichayapat

    2017-07-01

    Full Text Available BackgroundMuscle spasticity is a disability caused by damage to the pyramidal system. Standard treatments for spasticity include muscle stretching, antispastic medications, and tendon release surgeries, but treatment outcomes remain unsatisfactory. Anodal transcranial direct current stimulation (tDCS in patients with muscle spasticity is known to result in significant improvement in spastic tone (p < 0.001. However, the mechanism of action by which tDCS treatment affects spasticity remains unclear. This pilot study aimed to investigate the effect of anodal tDCS upon brain metabolites in the left basal ganglia and ipsilateral primary motor cortex (M1 in children with spastic cerebral palsy (CP.Materials and methodsThis study consisted of three steps: a baseline evaluation, a treatment period, and a follow-up period. During the treatment period, patients were given 20 min of 1 mA anodal tDCS over the left M1 for five consecutive days. Outcomes were compared between pre- and immediate posttreatment in terms of brain metabolites, Tardieu scales, and the quality of upper extremity skills test.ResultsTen patients with spastic CP were enrolled. Following tDCS, there were significant increases in the ratio of N-acetylaspartate (NAA/creatine (Cr (p = 0.030, choline (Cho/Cr (p = 0.043, and myoinositol (mI/Cr (p = 0.035 in the basal ganglia. Moreover, increased glutamine–glutamate (Glx/Cr ratio in the left M1 (p = 0.008 was found. In addition, we also observed improvements in the extent of spasticity and hand function (p = 0.028.ConclusionFive consecutive days of anodal tDCS over the left M1 appeared statistically to reduce the degree of spasticity and increase NAA, Cho, mI, and Glx. Future research studies, involving a larger sample size of spastic CP patients undergoing tDCS is now warranted.

  20. 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....

  1. Novel Anode Catalyst for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    S. Basri

    2014-01-01

    Full Text Available PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni and iron (Fe. Multiwalled carbon nanotubes (MWCNTs are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX, X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, and X-ray photoelectron spectroscopy (XPS, are used to characterize the kinetic parameters of the hybrid catalyst. Cyclic voltammetry (CV is used to investigate the effects of adding Fe and Ni to the catalyst on the reaction kinetics. Additionally, chronoamperometry (CA tests were conducted to study the long-term performance of the catalyst for catalyzing the methanol oxidation reaction (MOR. The binding energies of the reactants and products are compared to determine the kinetics and potential surface energy for methanol oxidation. The FESEM analysis results indicate that well-dispersed nanoscale (2–5 nm PtRu particles are formed on the MWCNTs. Finally, PtRuFeNi/MWCNT improves the reaction kinetics of anode catalysts for DMFCs and obtains a mass current of 31 A g−1 catalyst.

  2. A physical model of Direct Methanol Fuel Cell anode impedance

    Science.gov (United States)

    Zago, M.; Casalegno, A.

    2014-02-01

    In the present work a physically based model of direct methanol fuel cell anode impedance has been developed and validated at different operating current densities. The proposed model includes the two-phase mass transport of both methanol and water through diffusion and catalyst layers and the methanol oxidation reaction involving CO adsorbed intermediate. Model simulations are in good quantitative agreement with experimental observations and permit to evaluate the origin of anode impedance features. Model results confirm that the high frequency 45° linear branch is caused by proton transport limitations within the catalyst layer and that the low frequency inductive behavior is due to surface coverage by CO reaction intermediate. Moreover model predictions elucidate the contribution to the impedance of mass transport phenomena through diffusion layer, that is relevant even at low current density and increases along the channel length. In particular liquid convective fluxes are considered as a process of pressure buildup and breakthrough at diffusion layer intersecting fibers, resulting in a discontinuous phenomenon. By means of this intermittent description it is possible to correctly reproduce mass transport limitations through diffusion layers, that manifest themselves as a second arch superimposed to the first one, peculiar of kinetic losses.

  3. Novel anode catalyst for direct methanol fuel cells.

    Science.gov (United States)

    Basri, S; Kamarudin, S K; Daud, W R W; Yaakob, Z; Kadhum, A A H

    2014-01-01

    PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs) but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni) and iron (Fe). Multiwalled carbon nanotubes (MWCNTs) are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS), are used to characterize the kinetic parameters of the hybrid catalyst. Cyclic voltammetry (CV) is used to investigate the effects of adding Fe and Ni to the catalyst on the reaction kinetics. Additionally, chronoamperometry (CA) tests were conducted to study the long-term performance of the catalyst for catalyzing the methanol oxidation reaction (MOR). The binding energies of the reactants and products are compared to determine the kinetics and potential surface energy for methanol oxidation. The FESEM analysis results indicate that well-dispersed nanoscale (2-5 nm) PtRu particles are formed on the MWCNTs. Finally, PtRuFeNi/MWCNT improves the reaction kinetics of anode catalysts for DMFCs and obtains a mass current of 31 A g(-1) catalyst.

  4. 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.

  5. A Randomized, Double-Blind, Sham-Controlled Trial of Transcranial Direct Current Stimulation in Attention-Deficit/Hyperactivity Disorder.

    Directory of Open Access Journals (Sweden)

    Camila Cosmo

    Full Text Available Current standardized treatments for cognitive impairment in attention-deficit/hyperactivity disorder remain limited and their efficacy restricted. Transcranial direct current stimulation (tDCS is a promising tool for enhancing cognitive performance in several neuropsychiatric disorders. Nevertheless, the effects of tDCS in reducing cognitive impairment in patients with attention-deficit/hyperactivity disorder (ADHD have not yet been investigated.A parallel, randomized, double-blind, sham-controlled trial was conducted to examine the efficacy of tDCS on the modulation of inhibitory control in adults with ADHD. Thirty patients were randomly allocated to each group and performed a go/no-go task before and after a single session of either anodal stimulation (1 mA over the left dorsolateral prefrontal cortex or sham stimulation.A nonparametric two-sample Wilcoxon rank-sum (Mann-Whitney test revealed no significant differences between the two groups of individuals with ADHD (tDCS vs. sham in regard to behavioral performance in the go/no go tasks. Furthermore, the effect sizes of group differences after treatment for the primary outcome measures-correct responses, impulsivity and omission errors--were small. No adverse events resulting from stimulation were reported.According to these findings, there is no evidence in support of the use of anodal stimulation over the left dorsolateral prefrontal cortex as an approach for improving inhibitory control in ADHD patients. To the best of our knowledge, this is the first clinical study to assess the cognitive effects of tDCS in individuals with ADHD. Further research is needed to assess the clinical efficacy of tDCS in this population.ClinicalTrials.gov NCT01968512.

  6. No effect of transcranial direct current stimulation of the dorsolateral prefrontal cortex on short-term memory.

    Science.gov (United States)

    Wang, Jing; Wen, Jian-Bing; Li, Xiao-Li

    2018-01-01

    Short-term memory refers to the capacity for holding information in mind for a short period of time with conscious memorization. It is an important ability for daily life and is impaired in several neurological and psychiatric disorders. Anodal transcranial direct current stimulation (tDCS) applied to the dorsolateral prefrontal cortex (DLPFC) was reported to enhance the capability of short-term memory in healthy subjects. However, results were not consistent and what is the possible impact factor is not known. One important factor that may significantly influence the effect of tDCS is the timing of tDCS administration. In order to explore whether tDCS impact short-term memory and the optimal timing of tDCS administration, we applied anodal tDCS to the left DLPFC to explore the modulatory effect of online and off-line tDCS on digit span as well as visual short-term memory performance in healthy subjects. Results showed tDCS of the left DLPFC did not influence intentional digit span memory performance, whether before the task or during the task. In addition, tDCS of the DLPFC administered before the task showed no effect on visual short-term memory, while there was a trend of increase in false alarm when tDCS of the DLPFC administered during the task. These results did not provide evidence for the enhancement of short-term memory by tDCS of the left DLPFC in healthy subjects, but it suggested an importance of administration time for visual short-term memory. Further studies are required to taking into account the baseline performance of subjects and time-dependence feature of tDCS. © 2017 John Wiley & Sons Ltd.

  7. The effects of transcranial direct current stimulation on conscious perception of sensory inputs from hand palm and dorsum.

    Science.gov (United States)

    Westgeest, Annette; Morales, Merche; Cabib, Christopher; Valls-Sole, Josep

    2014-12-01

    Conscious perception of sensory signals depends in part on stimulus salience, relevance and topography. Letting aside differences at skin receptor level and afferent fibres, it is the CNS that makes a contextual selection of relevant sensory inputs. We hypothesized that subjective awareness (AW) of the time at which a sensory stimulus is perceived, a cortical function, may be differently modified by cortical stimulation, according to site and type of the stimulus. In 24 healthy volunteers, we examined the effects of transcranial direct current stimulation (tDCS) on the assessment of AW to heat pain or weak electrical stimuli applied to either the hand palm or dorsum. We also recorded the vertex-evoked potentials to the same stimuli. The assessment was done before, during and after cathodal or anodal tDCS over the parietal cortex contralateral to the hand receiving the stimuli. At baseline, AW to thermal stimuli was significantly longer for palm than for dorsum (P stimulation sites were observed for the electrical stimuli. Both cathodal and anodal tDCS caused a significant shortening of AW to thermal stimuli in the palm but not in the dorsum, and no effects on AW to electrical stimuli. Longer AW in the palm than in the dorsum may be attributable to differences in skin thickness. However, the selectivity of the effects of tDCS on AW to thermal stimulation of the glabrous skin reflects the specificity of CNS processing for site and type of sensory inputs. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  8. Individualized model predicts brain current flow during transcranial direct-current stimulation treatment in responsive stroke patient.

    Science.gov (United States)

    Datta, Abhishek; Baker, Julie M; Bikson, Marom; Fridriksson, Julius

    2011-07-01

    Although numerous published reports have demonstrated the beneficial effects of transcranial direct-current stimulation (tDCS) on task performance, fundamental questions remain regarding the optimal electrode configuration on the scalp. Moreover, it is expected that lesioned brain tissue will influence current flow and should therefore be considered (and perhaps leveraged) in the design of individualized tDCS therapies for stroke. The current report demonstrates how different electrode configurations influence the flow of electrical current through brain tissue in a patient who responded positively to a tDCS treatment targeting aphasia. The patient, a 60-year-old man, sustained a left hemisphere ischemic stroke (lesion size = 87.42 mL) 64 months before his participation. In this study, we present results from the first high-resolution (1 mm(3)) model of tDCS in a brain with considerable stroke-related damage; the model was individualized for the patient who received anodal tDCS to his left frontal cortex with the reference cathode electrode placed on his right shoulder. We modeled the resulting brain current flow and also considered three additional reference electrode positions: right mastoid, right orbitofrontal cortex, and a "mirror" configuration with the anode over the undamaged right cortex. Our results demonstrate the profound effect of lesioned tissue on resulting current flow and the ability to modulate current pattern through the brain, including perilesional regions, through electrode montage design. The complexity of brain current flow modulation by detailed normal and pathologic anatomy suggest: (1) That computational models are critical for the rational interpretation and design of individualized tDCS stroke-therapy; and (2) These models must accurately reproduce head anatomy as shown here. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Reactivity descriptors for direct methanol fuel cell anode catalysts

    DEFF Research Database (Denmark)

    Ferrin, Peter; Nilekar, Anand Udaykumar; Greeley, Jeff

    2008-01-01

    We have investigated the anode reaction in direct methanol fuel cells using a database of adsorption free energies for 16 intermediates on 12 close-packed transition metal surfaces calculated with periodic, self-consistent, density functional theory (DFT-GGA). This database, combined with a simple...... electrokinetic model of the methanol electrooxidation reaction, yields mechanistic insights that are consistent with previous experimental and theoretical studies on Pt, and extends these insights to a broad spectrum of other transition metals. In addition, by using linear scaling relations between...... the adsorption free energies of various intermediates in the reaction network, we find that the results determined with the full database of adsorption energies can be estimated by knowing only two key descriptors for each metal surface: the free energies of OH and CO on the surface. Two mechanisms for methanol...

  10. 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.

  11. The effect of transcranial direct current stimulation on contrast sensitivity and visual evoked potential amplitude in adults with amblyopia

    Science.gov (United States)

    Ding, Zhaofeng; Li, Jinrong; Spiegel, Daniel P.; Chen, Zidong; Chan, Lily; Luo, Guangwei; Yuan, Junpeng; Deng, Daming; Yu, Minbin; Thompson, Benjamin

    2016-01-01

    Amblyopia is a neurodevelopmental disorder of vision that occurs when the visual cortex receives decorrelated inputs from the two eyes during an early critical period of development. Amblyopic eyes are subject to suppression from the fellow eye, generate weaker visual evoked potentials (VEPs) than fellow eyes and have multiple visual deficits including impairments in visual acuity and contrast sensitivity. Primate models and human psychophysics indicate that stronger suppression is associated with greater deficits in amblyopic eye contrast sensitivity and visual acuity. We tested whether transcranial direct current stimulation (tDCS) of the visual cortex would modulate VEP amplitude and contrast sensitivity in adults with amblyopia. tDCS can transiently alter cortical excitability and may influence suppressive neural interactions. Twenty-one patients with amblyopia and twenty-seven controls completed separate sessions of anodal (a-), cathodal (c-) and sham (s-) visual cortex tDCS. A-tDCS transiently and significantly increased VEP amplitudes for amblyopic, fellow and control eyes and contrast sensitivity for amblyopic and control eyes. C-tDCS decreased VEP amplitude and contrast sensitivity and s-tDCS had no effect. These results suggest that tDCS can modulate visual cortex responses to information from adult amblyopic eyes and provide a foundation for future clinical studies of tDCS in adults with amblyopia. PMID:26763954

  12. Combined transcranial direct current stimulation and robot-assisted arm training in subacute stroke patients: a pilot study.

    Science.gov (United States)

    Hesse, S; Werner, C; Schonhardt, E M; Bardeleben, A; Jenrich, W; Kirker, S G B

    2007-01-01

    Preliminary reports suggest that central stimulation may enhance the effect of conventional physical therapies after stroke. This pilot study examines the safety and methodology of using transcranial direct stimulation (tDCS) with robot-assisted arm training (AT), to inform planning a larger randomised controlled trial. Ten patients, after an ischaemic stroke 4-8 weeks before study onset, no history of epilepsy, participated. Eight had a cortical lesion and 2 had subcortical lesions: all had severe arm paresis and, co-incidentally, 5 had severe aphasia. Over six weeks, they received thirty 20 min-sessions of AT. During the first 7 minutes, 1.5mA of tDCS was applied, with the anode over the lesioned hemisphere and the cathode above the contralateral orbit. Arm and language impairment were assessed with the Fugl-Meyer motor score (FM, full range 0-66) and the Aachener Aphasie Test. No major side effects occurred. Arm function of three patients (two with a subcortical lesion) improved significantly, with FM scores increasing from 6 to 28, 10 to 49 and 11 to 48. In the remaining seven patients, all with cortical lesions, arm function changed little, FM scores did not increase more than 5 points. Unexpectedly, aphasia improved in 4 patients. These procedures are safe, and easy to use in a clinical setting. In future studies, patients should be stratified by degree of arm weakness and lesion site, also the unexpected aphasia improvement warrants following-up.

  13. Inferior parietal transcranial direct current stimulation with training improves cognition in anomic Alzheimer's disease and frontotemporal dementia.

    Science.gov (United States)

    Roncero, Carlos; Kniefel, Heike; Service, Erik; Thiel, Alexander; Probst, Stephan; Chertkow, Howard

    2017-06-01

    We evaluated whether transcranial direct current stimulation (tDCS) can improve picture-naming abilities in subjects with anomic Alzheimer or frontotemporal dementias. Using a double-blind crossover design, 10 participants were trained on picture naming over a series of 10 sessions with either 30 minutes of anodal (2 mA) tDCS stimulation to the left inferior parieto-temporal region (P3) or sham stimulation. We evaluated performance on a trained picture-naming list, an equivalent untrained list, and additional neuropsychological tasks. Participants improved significantly more receiving real stimulation rather than sham stimulation (40% vs. 19%, P  < .01), lasting at least 2 weeks after stimulation. Furthermore, these participants showed a small increase for untrained picture-naming items and digit span when they received real stimulation but a decrease when sham stimulation was received. tDCS stimulation has promise as a treatment for anomia in demented individuals and the effect can generalize to unstudied items as well as other cognitive abilities.

  14. 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.

  15. Transcranial direct current stimulation augments perceptual sensitivity and 24-hour retention in a complex threat detection task.

    Directory of Open Access Journals (Sweden)

    Brian Falcone

    Full Text Available We have previously shown that transcranial direct current stimulation (tDCS improved performance of a complex visual perceptual learning task (Clark et al. 2012. However, it is not known whether tDCS can enhance perceptual sensitivity independently of non-specific, arousal-linked changes in response bias, nor whether any such sensitivity benefit can be retained over time. We examined the influence of stimulation of the right inferior frontal cortex using tDCS on perceptual learning and retention in 37 healthy participants, using signal detection theory to distinguish effects on perceptual sensitivity (d' from response bias (ß. Anodal stimulation with 2 mA increased d', compared to a 0.1 mA sham stimulation control, with no effect on ß. On completion of training, participants in the active stimulation group had more than double the perceptual sensitivity of the control group. Furthermore, the performance enhancement was maintained for 24 hours. The results show that tDCS augments both skill acquisition and retention in a complex detection task and that the benefits are rooted in an improvement in sensitivity (d', rather than changes in response bias (ß. Stimulation-driven acceleration of learning and its retention over 24 hours may result from increased activation of prefrontal cortical regions that provide top-down attentional control signals to object recognition areas.

  16. Prefrontal versus motor cortex transcranial direct current stimulation (tDCS) effects on post-surgical opioid use.

    Science.gov (United States)

    Borckardt, Jeffrey J; Reeves, Scott T; Milliken, Cole; Carter, Brittan; Epperson, Thomas I; Gunselman, Ryan J; Madan, Alok; Del Schutte, H; Demos, Harry A; George, Mark S

    Pain is often a complaint that precedes total knee arthroplasty (TKA), however the procedure itself is associated with considerable post-operative pain lasting days to weeks which can predict longer-term surgical outcomes. Previously, we reported significant opioid-sparing effects of motor cortex transcranial direct current stimulation from a single-blind trial. In the present study, we used double-blind methodology to compare motor cortex tDCS and prefrontal cortex tDCS to both sham and active-control (active electrodes over non-pain modulating brain areas) tDCS. 58 patients undergoing unilateral TKA were randomly assigned to receive 4 20-min sessions (a total of 80 min) of tDCS (2 mA) post-surgery with electrodes placed to create 4 groups: 1) MOTOR (n = 14); anode-motor/cathode-right prefrontal, 2) PREFRONTAL (n = 16); anode-left-prefrontal/cathode-right-sensory, 3) ACTIVE-CONTROL (n = 15); anode-left-temporal-occipital junction/cathode-medial-anterior-premotor-area, and 4) SHAM (n = 13); 0 mA-current stimulation using placements 1 or 2. Patient controlled analgesia (PCA; hydromorphone) use was tracked during the ∼72-h post-surgery. Patients in the sham group and the active-control group used 15.4 mg (SD = 14.1) and 16.0 mg (SD = 9.7) of PCA hydromorphone respectively. There was no difference between the slopes of the cumulative PCA usage curves between these two groups (p = 0.25; ns). Patients in the prefrontal tDCS group used an average of 11.7 mg (SD = 5.0) of PCA hydromporhone, and the slope of the cumulative PCA usage curve was significantly lower than sham (p prefrontal cortex may be a reasonable approach to reducing post-TKA opioid requirements. Given the unexpected finding that motor cortex failed to produce an opioid sparing effect in this follow-up trial, further research in the area of post-operative cortical stimulation is still needed. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. 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

  18. 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

    2017-04-26

     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

  19. Repeated Transcranial Direct Current Stimulation Induces Behavioral, Metabolic and Neurochemical Effects in Rats on High-Calorie Diet

    Directory of Open Access Journals (Sweden)

    Agata Ziomber

    2018-01-01

    Full Text Available Due to its high prevalence, obesity is considered an epidemic, which stimulated research on non-invasive methods to reduce excess body fat. Transcranial direct current stimulation (tDCS is a non-invasive technique used to modulate the activity of cerebral cortex, which has already found increasing interest in medicine as a promising methodology. The aim of this study was to analyze the impact of tDCS on feeding behavior, metabolic abnormalities and neurotransmitters in certain brain areas involved in appetite control of obese rats. The male Wistar rats were divided into five subgroups depending on consumed diet effect (lean, obese and tDCS type (anodal, cathodal, sham, and no stimulation. Two 10-min daily sessions of tDCS for 8 consecutive days of the study were applied. Rats subjected to active tDCS (anodal right or cathodal left of the prefrontal cortex had reduced appetite and showed lesser body weight gain than the animals subjected to sham procedure or those receiving no stimulation at all. Furthermore, tDCS contributed to reduction of epididymal fat pads and to a decrease in blood concentration of leptin. Neurochemical examination revealed that tDCS modulated serotonin pathways of the reward-related brain areas and contributed to a significant decrease in the density of D2 but not D1 dopamine receptors in the dorsal striatum, recorded 5 h after the last stimulation. No significant effect of tDCS on dopamine and it's metabolites in examined brain regions was observed. It seems that the hypothalamus was not affected by tDCS application as no changes in measured neurotransmitters were detected at any examined time point. However, these results do not exclude the possibility of the delayed response of the monoamines in the examined brain areas to tDCS application. Altogether, these findings imply that repeated tDCS of the prefrontal cortex may change feeding behavior of obese rats. Either right anodal or left cathodal tDCS were sufficient to

  20. A Pilot Study on the Effects of Transcranial Direct Current Stimulation on Brain Rhythms and Entropy during Self-Paced Finger Movement using the Epoc Helmet.

    Science.gov (United States)

    Bodranghien, Florian C A A; Langlois Mahe, Margot; Clément, Serge; Manto, Mario U

    2017-01-01

    Transcranial direct current stimulation (tDCS) of the cerebellum is emerging as a novel non-invasive tool to modulate the activity of the cerebellar circuitry. In a single blinded study, we applied anodal tDCS (atDCS) of the cerebellum to assess its effects on brain entropy and brain rhythms during self-paced sequential finger movements in a group of healthy volunteers. Although wearable electroencephalogram (EEG) systems cannot compete with traditional clinical/laboratory set-ups in terms of accuracy and channel density, they have now reached a sufficient maturity to envision daily life applications. Therefore, the EEG was recorded with a comfortable and easy to wear 14 channels wireless helmet (Epoc headset; electrode location was based on the 10-20 system). Cerebellar neurostimulation modified brain rhythmicity with a decrease in the delta band (electrode F3 and T8, p Epoc headset.

  1. Combination of Transcranial Direct Current Stimulation and Neuromuscular Electrical Stimulation Improves Gait Ability in a Patient in Chronic Stage of Stroke.

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    Satow, Takeshi; Kawase, Tomotaka; Kitamura, Atsushi; Kajitani, Yuki; Yamaguchi, Takuya; Tanabe, Nobuhiko; Otoi, Reiko; Komuro, Taro; Kobayashi, Akira; Nagata, Hirokazu; Mima, Tatsuya

    2016-01-01

    Walking ability is important in stroke patients to maintain daily life. Nevertheless, its improvement is limited with conventional physical therapy in chronic stage. We report the case of a chronic stroke patient showing a remarkable improvement in gait function after a new neurorehabilitation protocol using transcranial direct current stimulation (tDCS) and neuromuscular electrical stimulation (NMES). A 62-year-old male with left putaminal hemorrhage suffered from severe right hemiparesis. He could move by himself with a wheelchair 1 year after the ictus. Anodal tDCS at the vertex (2 mA, 20 min) with NMES at the anterior tibialis muscle had been applied for 3 weeks. The Timed Up and Go test and 10-meter walk test improved after the intervention, which had been maintained for at least 1 month. This single case suggests the possibility that tDCS with NMES could be a new rehabilitation approach to improve the gait ability in chronic stroke patients.

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

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    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.

  3. Transcranial Direct Current Stimulation in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder (ADHD): A Pilot Study.

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    Bandeira, Igor Dórea; Guimarães, Rachel Silvany Quadros; Jagersbacher, João Gabriel; Barretto, Thiago Lima; de Jesus-Silva, Jéssica Regina; Santos, Samantha Nunes; Argollo, Nayara; Lucena, Rita

    2016-06-01

    Studies investigating the possible benefits of transcranial direct current stimulation on left dorsolateral prefrontal cortex in children and adolescents with attention-deficit hyperactivity disorder (ADHD) have not been performed. This study assesses the effect of transcranial direct current stimulation in children and adolescents with ADHD on neuropsychological tests of visual attention, visual and verbal working memory, and inhibitory control. An auto-matched clinical trial was performed involving transcranial direct current stimulation in children and adolescents with ADHD, using SNAP-IV and subtests Vocabulary and Cubes of the Wechsler Intelligence Scale for Children III (WISC-III). Subjects were assessed before and after transcranial direct current stimulation sessions with the Digit Span subtest of the WISC-III, inhibitory control subtest of the NEPSY-II, Corsi cubes, and the Visual Attention Test (TAVIS-3). There were 9 individuals with ADHD according to Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria. There was statistically significant difference in some aspects of TAVIS-3 tests and the inhibitory control subtest of NEPSY-II. Transcranial direct current stimulation can be related to a more efficient processing speed, improved detection of stimuli, and improved ability to switch between an ongoing activity and a new one. © The Author(s) 2016.

  4. Low intensity transcranial electric stimulation

    DEFF Research Database (Denmark)

    Antal, A.; 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...

  5. The effects of transcranial direct current stimulation on short-interval intracortical inhibition and intracortical facilitation: a systematic review and meta-analysis.

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    Biabani, Mana; Aminitehrani, Maryam; Zoghi, Maryam; Farrell, Michael; Egan, Gary; Jaberzadeh, Shapour

    2018-01-26

    Transcranial direct current stimulation (tDCS) is increasingly being used to affect the neurological conditions with deficient intracortical synaptic activities (i.e. Parkinson's disease and epilepsy). In addition, it is suggested that the lasting effects of tDCS on corticospinal excitability (CSE) have intracortical origin. This systematic review and meta-analysis aimed to examine whether tDCS has any effect on intracortical circuits. Eleven electronic databases were searched for the studies investigating intracortical changes induced by anodal (a) and cathodal (c) tDCS, in healthy individuals, using two paired-pulse transcranial magnetic stimulation (TMS) paradigms: short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Additionally, motor-evoked potential (MEP) size alterations, assessed by single-pulse TMS, were extracted from these studies to investigate the probable intracortical origin of tDCS effects on CSE. The methodological quality of included studies was examined using Physiotherapy Evidence Database (PEDro) and Downs and Black's (D&B) assessment tools. Thirteen research papers, including 24 experiments, were included in this study scoring good and medium quality in PEDro and D&B scales, respectively. Immediately following anodal tDCS (a-tDCS) applications, we found significant decreases in SICI, but increases in ICF and MEP size. However, ICF and MEP size significantly decreased, and SICI increased immediately following cathodal tDCS (c-tDCS). The results of this systematic review and meta-analysis reveal that a-tDCS changes intracortical activities (SICI and ICF) toward facilitation, whereas c-tDCS alters them toward inhibition. It can also be concluded that increases and decreases in CSE after tDCS application are associated with corresponding changes in intracortical activities. The results suggest that tDCS can be clinically useful to modulate intracortical circuits.

  6. Transcranial Direct Current Stimulation Does Not Influence the Speed-Accuracy Tradeoff in Perceptual Decision-making: Evidence from Three Independent Studies.

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    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.

  7. Effects of transcranial direct current stimulation on motor learning in healthy individuals: a systematic review

    Directory of Open Access Journals (Sweden)

    Águida Foerster

    Full Text Available Introduction Transcranial direct current stimulation (tDCS has been used to modify cortical excitability and promote motor learning. Objective To systematically review published data to investigate the effects of transcranial direct current stimulation on motor learning in healthy individuals. Methods Randomized or quasi-randomized studies that evaluated the tDCS effects on motor learning were included and the risk of bias was examined by Cochrane Collaboration’s tool. The following electronic databases were used: PubMed, Scopus, Web of Science, LILACS, CINAHL with no language restriction. Results It was found 160 studies; after reading the title and abstract, 17 of those were selected, but just 4 were included. All studies involved healthy, right-handed adults. All studies assessed motor learning by the Jebsen Taylor Test or by the Serial Finger Tapping Task (SFTT. Almost all studies were randomized and all were blinding for participants. Some studies presented differences at SFTT protocol. Conclusion The result is insufficient to draw conclusions if tDCS influences the motor learning. Furthermore, there was significant heterogeneity of the stimulation parameters used. Further researches are needed to investigate the parameters that are more important for motor learning improvement and measure whether the effects are long-lasting or limited in time.

  8. Molecular and elemental effects underlying the biochemical action of transcranial direct current stimulation (tDCS) in appetite control

    Science.gov (United States)

    Surowka, Artur D.; Ziomber, Agata; Czyzycki, Mateusz; Migliori, Alessandro; Kasper, Kaja; Szczerbowska-Boruchowska, Magdalena

    2018-04-01

    Recent studies highlight that obesity may alter the electric activity in brain areas triggering appetite and craving. Transcranial direct current brain stimulation (tDCS) has recently emerged as a safe alternative for treating food addiction via modulating cortical excitability without any high-risk surgical procedure to be utilized. As for anodal-type tDCS (atDCS), we observe increased excitability and spontaneous firing of the cortical neurons, whilst for the cathodal-type tDCS (ctDCS) a significant decrease is induced. Unfortunately, for the method to be fully used in a clinical setting, its biochemical action mechanism must be precisely defined, although it is proposed that molecular remodelling processes play in concert with brain activity changes involving the ions of: Na, Cl, K and Ca. Herein, we proposed for the first time Fourier transform infrared (FTIR) and synchrotron X-ray fluorescence (SRXRF) microprobes for a combined molecular and elemental analysis in the brain areas implicated appetite control, upon experimental treatment by either atDCS or ctDCS. The study, although preliminary, shows that by stimulating the prefrontal cortex in the rats fed high-caloric nutrients, the feeding behavior can be significantly changed, resulting in significantly inhibited appetite. Both, atDCS and ctDCS produced significant molecular changes involving qualitative and structural properties of lipids, whereas atDCS was found with a somewhat more significant effect on protein secondary structure in all the brain areas investigated. Also, tDCS was reported to reduce surface masses of Na, Cl, K, and Ca in almost all brain areas investigated, although the atDCS deemed to have a stronger neuro-modulating effect. Taken together, one can report that tDCS is an effective treatment technique, and its action mechanism in the appetite control seems to involve a variety of lipid-, protein- and metal/non-metal-ion-driven biochemical changes, regardless the current polarization.

  9. LONG-TERM EFFECTS OF TRANSCRANIAL DIRECT CURRENT STIMULATION IN CHRONIC POST-STROKE APHASIA: A PILOT STUDY

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    Lucilla eVestito

    2014-10-01

    Full Text Available Transcranial direct current stimulation (tDCS has been suggested to improve language function in patients with post-stroke aphasia. Most studies on aphasic patients, however, were conducted with a very limited follow-up period, if any. In this pilot, single-blind study on chronic post-stroke aphasic patients, we aimed to verify whether or not tDCS is able to extend its beneficial effects for a longer period of time (21 weeks after the end of stimulation. Three aphasic patients underwent anodal tDCS (A-tDCS, 20 min, 1.5 mA and sham stimulation (S-tDCS over the left frontal (perilesional region, coupled with a simultaneous naming training (on-line tDCS. Ten consecutive sessions (five days per week for two weeks were implemented. In the first five sessions we used a list of 40 figures, while in the subsequent five sessions we utilized a second set of 40 figures differing in word difficulty. At the end of the stimulation period we found a significant beneficial effect of A-tDCS (as compared to baseline and S-tDCS in all our subjects, regardless of word difficulty, although with some inter-individual differences. In the follow-up period, the percentage of correct responses persisted significantly better until the 16th week, when an initial decline in naming performance was observed. Up to the 21st week, the number of correct responses, though no longer significant, was still above the baseline level. These results in a small group of aphasic patients suggest a long-term beneficial effect of on-line A-tDCS.

  10. Impact of Uncertain Head Tissue Conductivity in the Optimization of Transcranial Direct Current Stimulation for an Auditory Target

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    Wagner, Sven; Burger, Martin; van Rienen, Ursula; Wolters, Carsten H

    2015-01-01

    Objective Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique to modify neural excitability. Using multi-array tDCS, we investigate the influence of inter-individually varying head tissue conductivity profiles on optimal electrode configurations for an auditory cortex stimulation. Approach In order to quantify the uncertainty of the optimal electrode configurations, multi-variate generalized Polynomial Chaos (gPC) expansions of the model solutions are used based on uncertain conductivity profiles of the compartments skin, skull, gray matter, and white matter. Stochastic measures, probability density functions, and sensitivity of the quantities of interest are investigated for each electrode and the current density at the target with the resulting stimulation protocols visualized on the head surface. Main results We demonstrate that the optimized stimulation protocols are only comprised of a few active electrodes, with tolerable deviations in the stimulation amplitude of the anode. However, large deviations in the order of the uncertainty in the conductivity profiles could be noted in the stimulation protocol of the compensating cathodes. Regarding these main stimulation electrodes, the stimulation protocol was most sensitive to uncertainty in skull conductivity. Finally, the probability that the current density amplitude in the auditory cortex target region is supra-threshold was below 50%. Significance The results suggest that an uncertain conductivity profile in computational models of tDCS can have a substantial influence on the prediction of optimal stimulation protocols for stimulation of the auditory cortex. The investigations carried out in this study present a possibility to predict the probability of providing a therapeutic effect with an optimized electrode system for future auditory clinical and experimental procedures of tDCS applications. PMID:26170066

  11. Does transcranial direct current stimulation during writing alleviate upper limb freezing in people with Parkinson's disease? A pilot study.

    Science.gov (United States)

    Broeder, Sanne; Heremans, Elke; Pinto Pereira, Marcelo; Nackaerts, Evelien; Meesen, Raf; Verheyden, Geert; Nieuwboer, Alice

    2018-02-28

    Transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) can boost motor performance in Parkinson's disease (PD) when it is applied at rest. However, the potential supplementary therapeutic effect of the concurrent application of tDCS during the training of motor tasks is largely unknown. The present study examined the effects of tDCS on upper limb motor blocks during a freezing-provoking writing task (the funnel task) requiring up- and down-stroke movements at alternating amplitudes. Ten PD patients and 10 age-matched controls underwent two sessions of writing combined with 20 min of anodal or sham tDCS on the left M1 in a randomized cross-over design. The primary outcome was the number of upper limb freezing episodes during five trials of the funnel task on a touch-sensitive tablet. PD patients showed a significant reduction in freezing episodes during tDCS compared to sham. No effects of tDCS were found for the amplitude, variability and speed of the strokes outside the freezing episodes. However, patients who reported freezing episodes in daily life (N = 6) showed a beneficial effect of tDCS on stroke characteristics. These results indicate a subgroup-dependent variability in response to non-invasive brain stimulation applied during the performance of motor tasks in PD. This warrants future studies to examine tDCS as an adjuvant tool for training programs aimed to reduce motor deficits related to freezing. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Effects of Transcranial Direct Current Stimulation Plus Physical Therapy on Gait in Patients With Parkinson Disease: A Randomized Controlled Trial.

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    Yotnuengnit, Pattarapol; Bhidayasiri, Roongroj; Donkhan, Rattana; Chaluaysrimuang, Juthamas; Piravej, Krisna

    2018-01-01

    The aim of the study was to study the combined effects of transcranial direct current stimulation (tDCS) and physical therapy on the walking ability of patients with Parkinson disease (PD). The study used an experimental, double-blinded, randomized controlled trial. After intervention, group 1 (only tDCS) demonstrated a significant increase in gait speed by 0.13 to 0.14 m/sec (17.8%-19.2%) and an increase in step length by 5.9 to 6.1 cm (14.0%-14.5%), whereas group 2 (tDCS and physical therapy) revealed a significant increase in gait speed by 0.10 to 0.13 m/sec (14.9%-19.4%) and step length by 4.5 to 5.4 cm (10.6%-12.8%) and group 3 (sham tDCS and physical therapy) showed a significant increase in gait speed by 0.09 to 0.14 m/sec (13.0%-20.3%) and step length by 3.0 to 5.4 cm (6.8%-12.3%). All these results lasted for at least 8 wks after intervention. Upon comparing the parameters of gait among the three groups at every follow-up visit, no significant difference was observed. Anodal tDCS or physical therapy could be used alone or together as a combination treatment to improve the walking speed of patients with Parkinson disease. The effects lasted for approximately 8 wks. The combination treatment was not superior to the use of tDCS or physical therapy alone.

  13. Transcranial Direct Current Stimulation in Patients with Prolonged Disorders of Consciousness: Combined Behavioral and Event-Related Potential Evidence

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    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

  14. The contribution of interindividual factors to variability of response in transcranial direct current stimulation studies

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    Lucia M Li

    2015-05-01

    Full Text Available There has been an explosion of research using transcranial direct current stimulation (tDCS for investigating and modulating human cognitive and motor function in healthy populations. It has also been used in many studies seeking to improve deficits in disease populations. With the slew of studies reporting ‘promising results’ for everything from motor recovery after stroke to boosting memory function, one could be easily seduced by the idea of tDCS being the next panacea for all neurological ills. However, huge variability exists in the reported effects of tDCS, with great variability in the effect sizes and even contradictory results reported. In this review, we consider the interindividual factors that may contribute to this variability. In particular, we discuss the importance of baseline neuronal state and features, anatomy, age and the inherent variability in the injured brain. We additionally consider how interindividual variability affects the results of motor evoked potential (MEP testing with transcranial magnetic stimulation (TMS, which, in turn, can lead to apparent variability in response to tDCS in motor studies.

  15. High-resolution Modeling Assisted Design of Customized and Individualized Transcranial Direct Current Stimulation Protocols

    Science.gov (United States)

    Bikson, Marom; Rahman, Asif; Datta, Abhishek; Fregni, Felipe; Merabet, Lotfi

    2012-01-01

    Objectives Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low-intensity currents facilitating or inhibiting spontaneous neuronal activity. tDCS is attractive since dose is readily adjustable by simply changing electrode number, position, size, shape, and current. In the recent past, computational models have been developed with increased precision with the goal to help customize tDCS dose. The aim of this review is to discuss the incorporation of high-resolution patient-specific computer modeling to guide and optimize tDCS. Methods In this review, we discuss the following topics: (i) The clinical motivation and rationale for models of transcranial stimulation is considered pivotal in order to leverage the flexibility of neuromodulation; (ii) The protocols and the workflow for developing high-resolution models; (iii) The technical challenges and limitations of interpreting modeling predictions, and (iv) Real cases merging modeling and clinical data illustrating the impact of computational models on the rational design of rehabilitative electrotherapy. Conclusions Though modeling for non-invasive brain stimulation is still in its development phase, it is predicted that with increased validation, dissemination, simplification and democratization of modeling tools, computational forward models of neuromodulation will become useful tools to guide the optimization of clinical electrotherapy. PMID:22780230

  16. Slow-oscillatory Transcranial Direct Current Stimulation Modulates Memory in Temporal Lobe Epilepsy by Altering Sleep Spindle Generators: A Possible Rehabilitation Tool.

    Science.gov (United States)

    Del Felice, Alessandra; Magalini, Alessandra; Masiero, Stefano

    2015-01-01

    Temporal lobe epilepsy (TLE) is often associated with memory deficits. Given the putative role for sleep spindles memory consolidation, spindle generators skewed toward the affected lobe in TLE subjects may be a neurophysiological marker of defective memory. Slow-oscillatory transcranial direct current stimulation (sotDCS) during slow waves sleep (SWS) has previously been shown to enhance sleep-dependent memory consolidation by increasing slow-wave sleep and modulating sleep spindles. To test if anodal sotDCS over the affected TL prior to a nap affects sleep spindles and whether this improves memory consolidation. Randomized controlled cross-over study. 12 people with TLE underwent sotDCS (0.75 Hz; 0-250 μV, 30 min) or sham before daytime nap. Declarative verbal and visuospatial learning were tested. Fast and slow spindle signals were recorded by 256-channel EEG during sleep. In both study arms, electrical source imaging (ESI) localized cortical generators. Neuropsychological data were analyzed with general linear model statistics or the Kruskal-Wallis test (P or Z memory performance (P = 0.048) emerged after sotDCS. SotDCS increased slow spindle generators current density (Z = 0.001), with a shift to the anterior cortical areas. Anodal sotDCS over the affected temporal lobe improves declarative and visuospatial memory performance by modulating slow sleep spindles cortical source generators. SotDCS appears a promising tool for memory rehabilitation in people with TLE. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Transcranial Direct Current Stimulation over the Medial Prefrontal Cortex and Left Primary Motor Cortex (mPFC-lPMC) Affects Subjective Beauty but Not Ugliness

    Science.gov (United States)

    Nakamura, Koyo; Kawabata, Hideaki

    2015-01-01

    Neuroaesthetics has been searching for the neural bases of the subjective experience of beauty. It has been demonstrated that neural activities in the medial prefrontal cortex (mPFC) and the left primary motor cortex (lPMC) correlate with the subjective experience of beauty. Although beauty and ugliness seem to be semantically and conceptually opposite, it is still unknown whether these two evaluations represent extreme opposites in unitary or bivariate dimensions. In this study, we applied transcranial direct current stimulation (tDCS) to examine whether non-invasive brain stimulation modulates two types of esthetic evaluation; evaluating beauty and ugliness. Participants rated the subjective beauty and ugliness of abstract paintings before and after the application of tDCS. Application of cathodal tDCS over the mPFC with anode electrode over the lPMC, which induced temporal inhibition of neural excitability of the mPFC, led to a decrease in beauty ratings but not ugliness ratings. There were no changes in ratings of both beauty and ugliness when applying anodal tDCS or sham stimulation over the mPFC. Results from our experiment indicate that the mPFC and the lPMC have a causal role in generating the subjective experience of beauty, with beauty and ugliness evaluations constituting two distinct dimensions. PMID:26696865

  18. 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.

  19. The stimulated social brain: effects of transcranial direct current stimulation on social cognition.

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    Sellaro, Roberta; Nitsche, Michael A; Colzato, Lorenza S

    2016-04-01

    Transcranial direct current stimulation (tDCS) is an increasingly popular noninvasive neuromodulatory tool in the fields of cognitive and clinical neuroscience and psychiatry. It is an inexpensive, painless, and safe brain-stimulation technique that has proven to be effective in modulating cognitive and sensory-perceptual functioning in healthy individuals and clinical populations. Importantly, recent findings have shown that tDCS may also be an effective and promising tool for probing the neural mechanisms of social cognition. In this review, we present the state-of-the-art of the field of tDCS research in social cognition. By doing so, we aim to gather knowledge of the potential of tDCS to modulate social functioning and social decision making in healthy humans, and to inspire future research investigations. © 2016 New York Academy of Sciences.

  20. How transcranial direct current stimulation can modulate implicit motor sequence learning and consolidation: A brief review

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    Branislav eSavic

    2016-02-01

    Full Text Available The purpose of this review is to investigate how transcranial direct current stimulation (tDCS can modulate implicit motor sequence learning and consolidation. So far, most of the studies have focused on the modulating effect of tDCS for explicit motor learning. Here, we focus explicitly on implicit motor sequence learning and consolidation in order to improve our understanding about the potential of tDCS to affect this kind of unconscious learning. Specifically, we concentrate on studies with the serial reaction time task (SRTT, the classical paradigm for measuring implicit motor sequence learning. The influence of tDCS has been investigated for the primary motor cortex, the premotor cortex, the prefrontal cortex, and the cerebellum. The results indicate that tDCS above the primary motor cortex gives raise to the most consistent modulating effects for both implicit motor sequence learning and consolidation.

  1. Effect of Transcranial Direct Current Stimulation of the Medial Prefrontal Cortex on the Gratitude of Individuals with Heterogeneous Ability in an Experimental Labor Market

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    Pengcheng Wang

    2017-11-01

    Full Text Available Gratitude is an important aspect of human sociality, which benefits mental health and interpersonal relationships. Thus, elucidating the neural mechanism of gratitude, which is only now beginning to be investigated, is important. To this end, this study specifies the medial prefrontal cortex (mPFC involved in the gratitude of heterogeneous individuals using the transcranial direct current stimulation (tDCS technique. Previous neural studies have shown the involvement of mPFC in social cognition and value evaluation, which are closely related to gratitude. However, the causal relationship between this neural area and gratitude has not been fully examined and the effect of individual social heterogeneity has been ignored. Meanwhile, behavioral economics studies have proposed that the abilities of employees in the labor market would affect their gratitude and emotional response. Thus, we designed an experiment based on gift exchange game to investigate the relationship between mPFC and gratitude of heterogeneous employees. Before the experiment, participants were asked to perform self-cognition of their abilities through an appropriately difficult task. We then used the effort of participants to imply their gratitude and analyzed the effort levels of employees with different abilities under anodal, cathodal, and sham stimulations. The results showed that employees under anodal stimulation were significantly likely to increase their effort than those under sham stimulation, and employees under cathodal stimulation ranked at the bottom of the list. Moreover, the effort levels of low-ability employees were obviously higher than those of high-ability employees. The cathodal stimulation of mPFC significantly reduced the effort levels of low-ability employees, whereas its anodal tDCS stimulation increased the effort levels of high-ability employees. These outcomes verify the relationship between mPFC and gratitude using tDCS and provided one of the first

  2. Transcranial direct current stimulation (tDCS) facilitates overall visual search response times but does not interact with visual search task factors.

    Science.gov (United States)

    Sung, Kyongje; Gordon, Barry

    2018-01-01

    Whether transcranial direct current stimulation (tDCS) affects mental functions, and how any such effects arise from its neural effects, continue to be debated. We investigated whether tDCS applied over the visual cortex (Oz) with a vertex (Cz) reference might affect response times (RTs) in a visual search task. We also examined whether any significant tDCS effects would interact with task factors (target presence, discrimination difficulty, and stimulus brightness) that are known to selectively influence one or the other of the two information processing stages posited by current models of visual search. Based on additive factor logic, we expected that the pattern of interactions involving a significant tDCS effect could help us colocalize the tDCS effect to one (or both) of the processing stages. In Experiment 1 (n = 12), anodal tDCS improved RTs significantly; cathodal tDCS produced a nonsignificant trend toward improvement. However, there were no interactions between the anodal tDCS effect and target presence or discrimination difficulty. In Experiment 2 (n = 18), we manipulated stimulus brightness along with target presence and discrimination difficulty. Anodal and cathodal tDCS both produced significant improvements in RTs. Again, the tDCS effects did not interact with any of the task factors. In Experiment 3 (n = 16), electrodes were placed at Cz and on the upper arm, to test for a possible effect of incidental stimulation of the motor regions under Cz. No effect of tDCS on RTs was found. These findings strengthen the case for tDCS having real effects on cerebral information processing. However, these effects did not clearly arise from either of the two processing stages of the visual search process. We suggest that this is because tDCS has a DIFFUSE, pervasive action across the task-relevant neuroanatomical region(s), not a discrete effect in terms of information processing stages.

  3. Effect of Transcranial Direct Current Stimulation of the Medial Prefrontal Cortex on the Gratitude of Individuals with Heterogeneous Ability in an Experimental Labor Market.

    Science.gov (United States)

    Wang, Pengcheng; Wang, Guangrong; Niu, Xiaofei; Shang, Huiliang; Li, Jianbiao

    2017-01-01

    Gratitude is an important aspect of human sociality, which benefits mental health and interpersonal relationships. Thus, elucidating the neural mechanism of gratitude, which is only now beginning to be investigated, is important. To this end, this study specifies the medial prefrontal cortex (mPFC) involved in the gratitude of heterogeneous individuals using the transcranial direct current stimulation (tDCS) technique. Previous neural studies have shown the involvement of mPFC in social cognition and value evaluation, which are closely related to gratitude. However, the causal relationship between this neural area and gratitude has not been fully examined and the effect of individual social heterogeneity has been ignored. Meanwhile, behavioral economics studies have proposed that the abilities of employees in the labor market would affect their gratitude and emotional response. Thus, we designed an experiment based on gift exchange game to investigate the relationship between mPFC and gratitude of heterogeneous employees. Before the experiment, participants were asked to perform self-cognition of their abilities through an appropriately difficult task. We then used the effort of participants to imply their gratitude and analyzed the effort levels of employees with different abilities under anodal, cathodal, and sham stimulations. The results showed that employees under anodal stimulation were significantly likely to increase their effort than those under sham stimulation, and employees under cathodal stimulation ranked at the bottom of the list. Moreover, the effort levels of low-ability employees were obviously higher than those of high-ability employees. The cathodal stimulation of mPFC significantly reduced the effort levels of low-ability employees, whereas its anodal tDCS stimulation increased the effort levels of high-ability employees. These outcomes verify the relationship between mPFC and gratitude using tDCS and provided one of the first instances of

  4. Biocatalytic anode for glucose oxidation utilizing carbon nanotubes for direct electron transfer with glucose oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Vaze, Abhay; Hussain, Nighat; Tang, Chi [Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060 (United States); Leech, Donal [School of Chemistry, National University of Ireland, Galway (Ireland); Rusling, James [Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060 (United States); Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06032 (United States); School of Chemistry, National University of Ireland, Galway (Ireland)

    2009-10-15

    Covalently linked layers of glucose oxidase, single-wall carbon nanotubes and poly-L-lysine on pyrolytic graphite resulted in a stable biofuel cell anode featuring direct electron transfer from the enzyme. Catalytic response observed upon addition of glucose was due to electrochemical oxidation of FADH{sub 2} under aerobic conditions. The electrode potential depended on glucose concentration. This system has essential attributes of an anode in a mediator-free biocatalytic fuel cell. (author)

  5. Effect of a single session of transcranial direct-current stimulation on balance and spatiotemporal gait variables in children with cerebral palsy: A randomized sham-controlled study

    Directory of Open Access Journals (Sweden)

    Luanda A. C. Grecco

    2014-10-01

    Full Text Available Background: Transcranial direct-current stimulation (tDCS has been widely studied with the aim of enhancing local synaptic efficacy and modulating the electrical activity of the cortex in patients with neurological disorders. Objective: The purpose of the present study was to determine the effect of a single session of tDCS regarding immediate changes in spatiotemporal gait and oscillations of the center of pressure (30 seconds in children with cerebral palsy (CP. Method: A randomized controlled trial with a blinded evaluator was conducted involving 20 children with CP between six and ten years of age. Gait and balance were evaluated three times: Evaluation 1 (before the stimulation, Evaluation 2 (immediately after stimulation, and Evaluation 3 (20 minutes after the stimulation. The protocol consisted of a 20-minute session of tDCS applied to the primary motor cortex at an intensity of 1 mA. The participants were randomly allocated to two groups: experimental group - anodal stimulation of the primary motor cortex; and control group - placebo transcranial stimulation. Results: Significant reductions were found in the experimental group regarding oscillations during standing in the anteroposterior and mediolateral directions with eyes open and eyes closed in comparison with the control group (p<0.05. In the intra-group analysis, the experimental group exhibited significant improvements in gait velocity, cadence, and oscillation in the center of pressure during standing (p<0.05. No significant differences were found in the control group among the different evaluations. Conclusion: A single session of tDCS applied to the primary motor cortex promotes positive changes in static balance and gait velocity in children with cerebral palsy.

  6. Safety Parameter Considerations of Anodal Transcranial Direct Current Stimulation in Rats

    Science.gov (United States)

    2017-10-01

    under standard laboratory conditions, including a 12 hour light/dark cycle with food and water available ad libitum. Following a ten day quarantine...Phosphate Buffer Saline Solution (PBS) followed by 4% paraformaldehyde (PFA) to fix and preserve tissue. After perfusion, brains were removed and placed

  7. Enhancing hybrid direct carbon fuel cell anode performance using Ag2O

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    A hybrid-direct carbon fuel cell (HDCFC), consisting of a molten slurry of solid carbon black and (Li-K)2CO3 added to the anode chamber of a solid oxide fuel cell, was characterized using current-potential-power density curves, electrochemical impedance spectroscopy, and cyclic voltammetry. Two...... types of experimental setups were employed in this study, an anode-supported full cell configuration (two electrodes, two atmospheres setup) and a 3-electrode electrolyte-supported half-cell setup (single atmosphere). Anode processes with and without catalysts were investigated as a function...... of temperature (700-800 °C) and anode sweep gas (N2, 4-100% CO2 in N2-CO2). It was shown that the addition of silver based catalysts (Ag, Ag2O, Ag2CO3) into the carbon-carbonate slurry enhanced the performance of the HDCFC....

  8. Can we improve pain and sleep in elderly individuals with transcranial direct current stimulation? – Results from a randomized controlled pilot study

    Directory of Open Access Journals (Sweden)

    Harvey MP

    2017-06-01

    Full Text Available Marie-Philippe Harvey,1,2 Dominique Lorrain,1,3 Marylie Martel,1,2 Kayla Bergeron-Vezina,1 Francis Houde,1,2 Mario Séguin,2,4 Guillaume Léonard1,2,5 1Research Centre on Aging, CIUSSS de l’Estrie-CHUS, 2Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3Department of Psychology, Université de Sherbrooke 4Department of Neurosurgery, Centre Hospitalier Universitaire de Sherbrooke, 5School of Rehabilitation, Université de Sherbrooke, Sherbrooke, QC, Canada Background: The prevalence of chronic pain and sleep disturbances substantially increases with age. Pharmacotherapy remains the primary treatment option for these health issues. However, side effects and drug interactions are difficult to control in elderly individuals.Aims: The objective of this study was to assess the feasibility of conducting a randomized sham-controlled trial and to collect preliminary data on the efficacy of transcranial direct current stimulation (tDCS to reduce pain and improve sleep in older adults suffering from chronic pain.Methods: Fourteen elderly individuals (mean age 71±7 years suffering from chronic pain and sleep complaints were randomized to receive either anodal tDCS, applied over the primary motor cortex (2 mA, 20 minutes, or sham tDCS, for 5 consecutive days. Pain was measured with visual analog scales, pain logbooks and questionnaires, while sleep was assessed with actigraphy, sleep diaries and questionnaires.Results: There were no missing data for pain and sleep measures, except for actigraphy, that generated several missing data. Blinding was maintained throughout the study, for both the evaluator and participants. Active but not sham tDCS significantly reduced pain (P<0.05. No change was observed in sleep parameters, in both the active and sham tDCS groups (all P≥0.18.Conclusion: The present study provides guidelines for the implementation of future tDCS studies in larger populations of elderly individuals. M1 anodal tDCS in this

  9. Transcranial direct current stimulation and neuroplasticity genes: implications for psychiatric disorders.

    Science.gov (United States)

    Chhabra, Harleen; Shivakumar, Venkataram; Agarwal, Sri Mahavir; Bose, Anushree; Venugopal, Deepthi; Rajasekaran, Ashwini; Subbanna, Manjula; Kalmady, Sunil V; Narayanaswamy, Janardhanan C; Debnath, Monojit; Venkatasubramanian, Ganesan

    2016-02-01

    Transcranial direct current stimulation (tDCS) is a non-invasive and well-tolerated brain stimulation technique with promising efficacy as an add-on treatment for schizophrenia and for several other psychiatric disorders. tDCS modulates neuroplasticity; psychiatric disorders are established to be associated with neuroplasticity abnormalities. This review presents the summary of research on potential genetic basis of neuroplasticity-modulation mechanism underlying tDCS and its implications for treating various psychiatric disorders. A systematic review highlighting the genes involved in neuroplasticity and their role in psychiatric disorders was carried out. The focus was on the established genetic findings of tDCS response relationship with BDNF and COMT gene polymorphisms. Synthesis of these preliminary observations suggests the potential influence of neuroplastic genes on tDCS treatment response. These include several animal models, pharmacological studies, mentally ill and healthy human subject trials. Taking into account the rapidly unfolding understanding of tDCS and the role of synaptic plasticity disturbances in neuropsychiatric disorders, in-depth evaluation of the mechanism of action pertinent to neuroplasticity modulation with tDCS needs further systematic research. Genes such as NRG1, DISC1, as well as those linked with the glutamatergic receptor in the context of their direct role in the modulation of neuronal signalling related to neuroplasticity aberrations, are leading candidates for future research in this area. Such research studies might potentially unravel observations that might have potential translational implications in psychiatry.

  10. Modulating Motor Learning through Transcranial Direct-Current Stimulation: An Integrative View.

    Science.gov (United States)

    Ammann, Claudia; Spampinato, Danny; Márquez-Ruiz, Javier

    2016-01-01

    Motor learning consists of the ability to improve motor actions through practice playing a major role in the acquisition of skills required for high-performance sports or motor function recovery after brain lesions. During the last decades, it has been reported that transcranial direct-current stimulation (tDCS), consisting in applying weak direct current through the scalp, is able of inducing polarity-specific changes in the excitability of cortical neurons. This low-cost, painless and well-tolerated portable technique has found a wide-spread use in the motor learning domain where it has been successfully applied to enhance motor learning in healthy individuals and for motor recovery after brain lesion as well as in pathological states associated to motor deficits. The main objective of this mini-review is to offer an integrative view about the potential use of tDCS for human motor learning modulation. Furthermore, we introduce the basic mechanisms underlying immediate and long-term effects associated to tDCS along with important considerations about its limitations and progression in recent years.

  11. Transcranial direct current stimulation (tDCS in behavioral and food addiction: A systematic review of efficacy, technical and methodological issues

    Directory of Open Access Journals (Sweden)

    Anne eSauvaget

    2015-10-01

    Full Text Available Objectives.Behavioral addictions (BA are complex disorders for which pharmacological and psychotherapeutic treatments have shown their limits. Non-invasive brain stimulation, among which transcranial direct current stimulation (tDCS, has opened up new perspectives in addiction treatment. The purpose of this work is to conduct a critical and systematic review of tDCS efficacy, and of technical and methodological considerations in the field of BA.Methods.A bibliographic search has been conducted on the Medline and ScienceDirect databases until December 2014, based on the following selection criteria: clinical studies on tDCS and BA (namely eating disorders, compulsive buying, Internet addiction, pathological gambling, sexual addiction, sports addiction, video games addiction. Study selection, data analysis and reporting were conducted according to the PRISMA guidelines.Results.Out of 402 potential articles, seven studies were selected. So far focusing essentially on abnormal eating, these studies suggest that tDCS (right prefrontal anode / left prefrontal cathode reduces food craving induced by visual stimuli.ConclusionsDespite methodological and technical differences between studies, the results are promising. So far, only few studies of tDCS in BA have been conducted. New research is recommended on the use of tDCS in BA, other than eating disorders.

  12. Hybrid Direct Carbon Fuel Cell Performance with Anode Current Collector Material

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Kammer Hansen, Kent

    2015-01-01

    The influence of the current collector on the performance of a hybrid direct carbon fuel cell (HDCFC), consisting of solid oxide fuel cell (SOFC) with a molten carbonate-carbon slurry in contact with the anode, has been investigated using current-voltage curves. Four different anode current...... collectors were studied: Au, Ni, Ag, and Pt. It was shown that the performance of the direct carbon fuel cell (DCFC) is dependent on the current collector materials, Ni and Pt giving the best performance, due to their catalytic activity. Gold is suggested to be the best material as an inert current collector...

  13. Repeated Transcranial Direct Current Stimulation Induces Behavioral, Metabolic and Neurochemical Effects in Rats on High-Calorie Diet

    OpenAIRE

    Agata Ziomber; Eugeniusz Rokita; Jolanta Kaszuba-Zwoinska; Irena Romańska; Jerzy Michaluk; Lucyna Antkiewicz-Michaluk

    2018-01-01

    Due to its high prevalence, obesity is considered an epidemic, which stimulated research on non-invasive methods to reduce excess body fat. Transcranial direct current stimulation (tDCS) is a non-invasive technique used to modulate the activity of cerebral cortex, which has already found increasing interest in medicine as a promising methodology. The aim of this study was to analyze the impact of tDCS on feeding behavior, metabolic abnormalities and neurotransmitters in certain brain areas in...

  14. F155. THE NEUROPHYSIOLOGICAL AND BEHAVIOURAL EFFECTS OF TRANSCRANIAL DIRECT CURRENT STIMULATION ON WORKING MEMORY AND EXECUTIVE FUNCTIONING IN SCHIZOPHRENIA

    Science.gov (United States)

    Orlov, Natasza; O’Daly, Owen; Tracy, Derek; Rothwell, John; Shergill, Sukhi

    2018-01-01

    Abstract Background Individuals with schizophrenia typically suffer a range of cognitive deficits, including in executive functioning (EF) and working memory (WM) [1,2]. Such difficulties are strongly predictive of functional outcomes, but there is a lack of effective therapeutic interventions [3]. Transcranial direct current stimulation (tDCS) is a novel neuromodulatory technique with emerging evidence of potential pro-cognitive applications; however there has been a dearth of understanding of mechanistic effects of this intervention [4]. The aim of this study was to evaluate the neurophysiological effects of tDCS during WM and EF assessment in individuals with schizophrenia. Methods We utilized functional magnetic resonance imaging (fMRI) to evaluate the impact of tDCS on WM and EF in individuals with schizophrenia, randomized to receive either ‘real’ or ‘sham’ (placebo tDCS). Participants completed a WM (blocked 0–3 back) and an EF (color-word Stroop) during 30 min of 2mA tDCS applied to Broadman area 10/46 (anode 35cm2); with cathode placed on right supraorbita. Sham stimulation was applied for 30 sec. tDCS was applied during fMRI (online) [5]. In addition to whole brain, we also conducted task relevant region of interest analysis (ROI) to compare mean frontal and prefrontal (Broadman are 10/46 mask) and anterior cingulate cortex (ACC) activity between the two groups during tDCS. All analyses were restricted a p-value of 0.05, following family wise-error correction (FWE). Results There were no between-group differences in socio-demographic or clinical characteristics (Tab 1.) Participants did not differ on WM task performance during online tDCS (Tab 2). However, there were significant between-group differences in manipulation of information with the real tDCS performing significantly better than sham, controlled for baseline (b=0.68, CI 0.14 - 1.21; p=0.044) after consolidation [6]. During WM the ROI analysis demonstrated increased activation

  15. High pressure anode operation of direct methanol fuel cells for carbon dioxide management

    Science.gov (United States)

    Lundin, Michael D.; McCready, Mark J.

    Experiments with independent pressurization of the direct methanol fuel cell anode and cathode allow for the observation of DMFC operation with carbon dioxide gas formation suppressed. Results indicate that the limiting current density is strongly related to the applied pressure, and, therefore, to the presence of CO 2 in the liquid phase. An additional experiment where CO 2 is allowed to accumulate in recycled anode fuel solution over a period of time and is then stripped from solution using nitrogen gas indicates that the presence of CO 2 in anode fuel solution at any pressure contributes to significant decreases in power and current density. Because CO 2 bubbles are ubiquitous in direct methanol fuel cells, this finding is key to the optimization of these systems.

  16. 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.

  17. Action mechanisms of transcranial direct current stimulation in Alzheimer´s disease and memory loss

    Directory of Open Access Journals (Sweden)

    Niels eHansen

    2012-05-01

    Full Text Available The pharmacological treatment of Alzheimer´s disease (AD is often limited and accompanied by drug side effects. Thus alternative therapeutic strategies such as non-invasive brain stimulation are needed. Few studies have demonstrated that transcranial direct current stimulation (tDCS, a method of neuromodulation with consecutive robust excitability changes within the stimulated cortex area, is beneficial in AD. There is also evidence that tDCS enhances memory function in cognitive rehabilitation in depressive patients, Parkinson´s disease and stroke. TDCS improves working and visual recognition memory in humans and object-recognition learning in the elderly. Neurobiological mechanisms of AD comprise changes in neuronal activity and the cerebral blood flow caused by altered microvasculature, synaptic dysregulation from ß-amyloid peptide accumulation, altered neuromodulation by degeneration of modulatory amine transmitter systems, altered brain oscillations, and changes in network connectivity. tDCS alters (i neuronal activity and (ii human cerebral blood flow, (iii has synaptic and non-synaptic after-effects (iv, can modify neurotransmitters polarity-dependently, (v and alter oscillatory brain activity and (vi functional connectivity patterns in the brain. It thus is reasonable to use tDCS as a therapeutic instrument in AD as it improves cognitive function in manner based on a disease mechanism. Moreover, it might prove valuable in other types of dementia. Future large-scale clinical and mechanism-oriented studies may enable to identify its therapeutic validity in other types of demential disorders.

  18. Action mechanisms of transcranial direct current stimulation in Alzheimer's disease and memory loss.

    Science.gov (United States)

    Hansen, Niels

    2012-01-01

    The pharmacological treatment of Alzheimer's disease (AD) is often limited and accompanied by drug side effects. Thus alternative therapeutic strategies such as non-invasive brain stimulation are needed. Few studies have demonstrated that transcranial direct current stimulation (tDCS), a method of neuromodulation with consecutive robust excitability changes within the stimulated cortex area, is beneficial in AD. There is also evidence that tDCS enhances memory function in cognitive rehabilitation in depressive patients, Parkinson's disease, and stroke. tDCS improves working and visual recognition memory in humans and object-recognition learning in the elderly. AD's neurobiological mechanisms comprise changes in neuronal activity and the cerebral blood flow (CBF) caused by altered microvasculature, synaptic dysregulation from ß-amyloid peptide accumulation, altered neuromodulation via degenerated modulatory amine transmitter systems, altered brain oscillations, and changes in network connectivity. tDCS alters (i) neuronal activity and (ii) human CBF, (iii) has synaptic and non-synaptic after-effects (iv), can modify neurotransmitters polarity-dependently, (v) and alter oscillatory brain activity and (vi) functional connectivity patterns in the brain. It thus is reasonable to use tDCS as a therapeutic instrument in AD as it improves cognitive function in manner based on a disease mechanism. Moreover, it could prove valuable in other types of dementia. Future large-scale clinical and mechanism-oriented studies may enable us to identify its therapeutic validity in other types of demential disorders.

  19. Transcranial direct current stimulation of the medial prefrontal cortex dampens mind-wandering in men.

    Science.gov (United States)

    Bertossi, Elena; Peccenini, Ludovica; Solmi, Andrea; Avenanti, Alessio; Ciaramelli, Elisa

    2017-12-05

    Mind-wandering, the mind's capacity to stray from external events and generate task-unrelated thought, has been associated with activity in the brain default network. To date, little is understood about the contribution of individual nodes of this network to mind-wandering. Here, we investigated the role of medial prefrontal cortex (mPFC) in mind-wandering, by perturbing this region with transcranial direct current stimulation (tDCS). Young healthy participants performed a choice reaction time task both before and after receiving cathodal tDCS over mPFC, and had their thoughts periodically sampled. We found that tDCS over mPFC - but not occipital or sham tDCS - decreased the propensity to mind-wander. The tDCS-induced reduction in mind-wandering occurred in men, but not in women, and was accompanied by a change in the content of task-unrelated though, which became more related to other people (as opposed to the self) following tDCS. These findings indicate that mPFC is crucial for mind-wandering, possibly by helping construction of self-relevant scenarios capable to divert attention inward, away from perceptual reality. Gender-related differences in tDCS-induced changes suggest that mPFC controls mind-wandering differently in men and women, which may depend on differences in the structural and functional organization of distributed brain networks governing mind-wandering, including mPFC.

  20. Relationship of herpes simplex encephalitis and transcranial direct current stimulation--a case report.

    Science.gov (United States)

    Yang, Yuanbin; Xiao, Juan; Song, Haiqing; Wang, Ralph; Hussain, Mohammed; Song, Weiqun

    2015-04-01

    We report a rare case of relapsing herpes simplex encephalitis in a-37-year-old patient which was previously confirmed by positive polymerase chain reaction, herpes simplex virus (HSV) type1 IgG antibodies in cerebrospinal fluid and characterized on MRI. During the first admission, he was treated with continuous acyclovir treatment for one month with clinical improvement except for residual aphasia, for which he received a course of outpatient transcranial direct current stimulation (tDCS). A constant current of 1.2 mA was applied for 20 min twice daily. After the 4th day the patient was found to be irritable and uncooperative by staff and family members. A subsequent MRI showed significant deterioration of the lesion on comparison to the first MRI which led to discontinuation of tDCS.The relatively rapid exacerbation of HSV in only a few days is unusual. Our aim is to discuss if tDCS is related to HSV relapse and in doing so highlight possible mechanisms. Copyright © 2015. Published by Elsevier B.V.

  1. 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.

  2. Application and outcomes of therapy combining transcranial direct current stimulation and virtual reality: a systematic review.

    Science.gov (United States)

    Massetti, Thais; Crocetta, Tânia Brusque; Silva, Talita Dias da; Trevizan, Isabela Lopes; Arab, Claudia; Caromano, Fátima Aparecida; Monteiro, Carlos Bandeira de Mello

    2017-08-01

    To evaluate the methods and major outcomes of transcranial direct current stimulation (tDCS) combined with virtual reality (VR) therapy in randomized controlled trials. A systematic review was performed following PRISMA guidelines using PubMed, PubMed Central, Web of Science and CAPES periodic databases, with no time restriction. The studies were screened for the following inclusion criteria: human subjects, combination of VR and tDCS methods, and randomized controlled study design. All potentially relevant articles were independently reviewed by two researchers, who reached a consensus on which articles met the inclusion criteria. The PEDro scale was used to evaluate the studies. Eleven studies were included, all of which utilized a variety of tDCS and VR application methods. The main outcomes were found to be beneficial in intervention groups of different populations, including improvements in body sway, gait, stroke recovery, pain management and vegetative reactions. The use of tDCS combined with VR showed positive results in both healthy and impaired patients. Future studies with larger sample sizes and homogeneous participants are required to confirm the benefits of tDCS and VR. Implications for Rehabilitation tDCS with VR intervention can be an alternative to traditional rehabilitation programs. tDCS with VR is a promising type of intervention with a variety of positive effects. Application of tDCS with VR is appropriated to both healthy and impaired patients. There is no consensus of tDCS with VR application.

  3. Reducing aggressive responses to social exclusion using transcranial direct current stimulation.

    Science.gov (United States)

    Riva, Paolo; Romero Lauro, Leonor J; DeWall, C Nathan; Chester, David S; Bushman, Brad J

    2015-03-01

    A vast body of research showed that social exclusion can trigger aggression. However, the neural mechanisms involved in regulating aggressive responses to social exclusion are still largely unknown. Transcranial direct current stimulation (tDCS) modulates the excitability of a target region. Building on studies suggesting that activity in the right ventrolateral pre-frontal cortex (rVLPFC) might aid the regulation or inhibition of social exclusion-related distress, we hypothesized that non-invasive brain polarization through tDCS over the rVLPFC would reduce behavioral aggression following social exclusion. Participants were socially excluded or included while they received tDCS or sham stimulation to the rVLPFC. Next, they received an opportunity to aggress. Excluded participants demonstrated cognitive awareness of their inclusionary status, yet tDCS (but not sham stimulation) reduced their behavioral aggression. Excluded participants who received tDCS stimulation were no more aggressive than included participants. tDCS stimulation did not influence socially included participants' aggression. Our findings provide the first causal test for the role of rVLPFC in modulating aggressive responses to social exclusion. Our findings suggest that modulating activity in a brain area (i.e. the rVLPFC) implicated in self-control and emotion regulation can break the link between social exclusion and aggression. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  4. Transcranial Direct Current Stimulation Facilitates Associative Learning and Alters Functional Connectivity in the Primate Brain.

    Science.gov (United States)

    Krause, Matthew R; Zanos, Theodoros P; Csorba, Bennett A; Pilly, Praveen K; Choe, Jaehoon; Phillips, Matthew E; Datta, Abhishek; Pack, Christopher C

    2017-10-23

    There has been growing interest in transcranial direct current stimulation (tDCS), a non-invasive technique purported to modulate neural activity via weak, externally applied electric fields. Although some promising preliminary data have been reported for applications ranging from stroke rehabilitation to cognitive enhancement, little is known about how tDCS affects the human brain, and some studies have concluded that it may have no effect at all. Here, we describe a macaque model of tDCS that allows us to simultaneously examine the effects of tDCS on brain activity and behavior. We find that applying tDCS to right prefrontal cortex improves monkeys' performance on an associative learning task. While firing rates do not change within the targeted area, tDCS does induce large low-frequency oscillations in the underlying tissue. These oscillations alter functional connectivity, both locally and between distant brain areas, and these long-range changes correlate with tDCS's effects on behavior. Together, these results are consistent with the idea that tDCS leads to widespread changes in brain activity and suggest that it may be a valuable method for cheaply and non-invasively altering functional connectivity in humans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Transcranial direct current stimulation in post-stroke dysphagia: a systematic review of randomized controlled trials

    Directory of Open Access Journals (Sweden)

    Kavian Ghandehari

    2016-07-01

    Full Text Available Introduction: The aim of this research was to systematically review all the randomized controlled trials that have evaluated the effect of transcranial direct current stimulation (tDCS on post-stroke dysphagia. Methods: Three electronic databases were searched for relevant articles that were uploaded from their inception to March 2015: PubMed, Cochrane Library (Cochrane Central Register of Controlled Trials, and Scopus. All data was that was related to the location of the cerebrovascular accident (CVA, the parameters of tDCS, post-stroke time to commencement of tDCS, the stimulated hemisphere, stimulation dose, any outcome measurements, and follow-up duration were extracted and assessed. Finally, a number of observations were generated through a qualitative synthesis of the extracted data.Result: Three eligible randomized controlled trials were included in the systematic review. All three trials reported that, in comparison to a placebo, tDCS had a statistically significant effect on post-stroke dysphagia.Discussion: The results of our systematic review suggest that tDCS may represent a promising novel treatment for post-stroke dysphagia. However, to date, little is known about the optimal parameters of tDCS for relieving post-stroke dysphagia. Further studies are warranted to refine this promising intervention by exploring the optimal parameters of tDCS.Conclusion: Since brainstem swallowing centers have bilateral cortical innervations, measures that enhance cortical input and sensorimotor control of brainstem swallowing may facilitate recovery from dysphagia.

  6. High-Definition transcranial direct current stimulation in early onset epileptic encephalopathy: a case study.

    Science.gov (United States)

    Meiron, Oded; Gale, Rena; Namestnic, Julia; Bennet-Back, Odeya; David, Jonathan; Gebodh, Nigel; Adair, Devin; Esmaeilpour, Zeinab; Bikson, Marom

    2018-01-01

    Early onset epileptic encephalopathy is characterized by high daily seizure-frequency, multifocal epileptic discharges, severe psychomotor retardation, and death at infancy. Currently, there are no effective treatments to alleviate seizure frequency and high-voltage epileptic discharges in these catastrophic epilepsy cases. The current study examined the safety and feasibility of High-Definition transcranial direct current stimulation (HD-tDCS) in reducing epileptiform activity in a 30-month-old child suffering from early onset epileptic encephalopathy. HD-tDCS was administered over 10 intervention days spanning two weeks including pre- and post-intervention video-EEG monitoring. There were no serious adverse events or side effects related to the HD-tDCS intervention. Frequency of clinical seizures was not significantly reduced. However, interictal sharp wave amplitudes were significantly lower during the post-intervention period versus baseline. Vital signs and blood biochemistry remained stable throughout the entire study. These exploratory findings support the safety and feasibility of 4 × 1 HD-tDCS in early onset epileptic encephalopathy and provide the first evidence of HD-tDCS effects on paroxysmal EEG features in electroclinical cases under the age of 36 months. Extending HD-tDCS treatment may enhance electrographic findings and clinical effects.

  7. 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.

  8. Transcranial Direct Current Stimulation in Substance Use Disorders: A Systematic Review of Scientific Literature.

    Science.gov (United States)

    Lupi, Matteo; Martinotti, Giovanni; Santacroce, Rita; Cinosi, Eduardo; Carlucci, Maria; Marini, Stefano; Acciavatti, Tiziano; di Giannantonio, Massimo

    2017-09-01

    New treatment options such as noninvasive brain stimulation have been recently explored in the field of substance use disorders (SUDs), including transcranial direct current stimulation (tDCS). In light of this, we have performed a review of the scientific literature to assess efficacy and technical and methodological issues resulting from applying tDCS to the field of SUDs. Our analysis highlighted the following selection criteria: clinical studies on tDCS and SUDs (alcohol, caffeine, cannabis, cocaine, heroin, methamphetamine, and nicotine). Study selection, data analysis, and reporting were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Exclusion criteria were as follows: clinical studies about tDCS among behavioral addiction; review and didactic articles; physiopathological studies; and case reports. Eighteen scientific papers were selected out of 48 articles. Among these, 16 studied the efficacy of tDCS applied to the dorsolateral prefrontal cortex, and 8 suggested the efficacy of tDCS in reducing substance craving. In light of these data, it is premature to conclude that tDCS over the dorsolateral prefrontal cortex is a very efficient technique in reducing craving. Small sample size, different stimulation protocols, and study duration were the main limitations. However, the efficacy of tDCS in treating SUDs requires further investigation.

  9. Pitch Memory in Nonmusicians and Musicians: Revealing Functional Differences Using Transcranial Direct Current Stimulation.

    Science.gov (United States)

    Schaal, N K; Krause, V; Lange, K; Banissy, M J; Williamson, V J; Pollok, B

    2015-09-01

    For music and language processing, memory for relative pitches is highly important. Functional imaging studies have shown activation of a complex neural system for pitch memory. One region that has been shown to be causally involved in the process for nonmusicians is the supramarginal gyrus (SMG). The present study aims at replicating this finding and at further examining the role of the SMG for pitch memory in musicians. Nonmusicians and musicians received cathodal transcranial direct current stimulation (tDCS) over the left SMG, right SMG, or sham stimulation, while completing a pitch recognition, pitch recall, and visual memory task. Cathodal tDCS over the left SMG led to a significant decrease in performance on both pitch memory tasks in nonmusicians. In musicians, cathodal stimulation over the left SMG had no effect, but stimulation over the right SMG impaired performance on the recognition task only. Furthermore, the results show a more pronounced deterioration effect for longer pitch sequences indicating that the SMG is involved in maintaining higher memory load. No stimulation effect was found in both groups on the visual control task. These findings provide evidence for a causal distinction of the left and right SMG function in musicians and nonmusicians. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. 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.

  11. Enhancement of object detection with transcranial direct current stimulation is associated with increased attention

    Directory of Open Access Journals (Sweden)

    Coffman Brian A

    2012-09-01

    Full Text Available Abstract Background We previously found that Transcranial Direct Current Stimulation (tDCS improves learning and performance in a task where subjects learn to detect potential threats indicated by small target objects hidden in a complex virtual environment. In the present study, we examined the hypothesis that these effects on learning and performance are related to changes in attention. The effects of tDCS were tested for three forms of attention (alerting, orienting, and executive attention using the Attention Network Task (ANT, which were compared with performance on the object-learning task. Results Participants received either 0.1 mA (N = 10 or 2.0 mA (N = 9 tDCS during training and were tested for performance in object-identification before training (baseline-test and again immediately after training (immediate test. Participants next performed the Attention Networks Task (ANT, and were later tested for object-identification performance a final time (delayed test. Alerting, but not orienting or executive attention, was significantly higher for participants receiving 2.0 mA compared with 0.1 mA tDCS (p p  Conclusions These results indicate that tDCS enhancement of performance in this task may be related in part to the enhancement of alerting attention, which may benefit the initial identification, learning and/or subsequent recognition of target objects indicating potential threats.

  12. Transcranial Cerebellar Direct Current Stimulation Enhances Verb Generation but Not Verb Naming in Poststroke Aphasia.

    Science.gov (United States)

    Marangolo, Paola; Fiori, Valentina; Caltagirone, Carlo; Pisano, Francesca; Priori, Alberto

    2018-02-01

    Although the role of the cerebellum in motor function is well recognized, its involvement in the lexical domain remains to be further elucidated. Indeed, it has not yet been clarified whether the cerebellum is a language structure per se or whether it contributes to language processing when other cognitive components (e.g., cognitive effort, working memory) are required by the language task. Neuromodulation studies on healthy participants have suggested that cerebellar transcranial direct current stimulation (tDCS) is a valuable tool to modulate cognitive functions. However, so far, only a single case study has investigated whether cerebellar stimulation enhances language recovery in aphasic individuals. In a randomized, crossover, double-blind design, we explored the effect of cerebellar tDCS coupled with language treatment for verb improvement in 12 aphasic individuals. Each participant received cerebellar tDCS (20 min, 2 mA) in four experimental conditions: (1) right cathodal and (2) sham stimulation during a verb generation task and (3) right cathodal and (4) sham stimulation during a verb naming task. Each experimental condition was run in five consecutive daily sessions over 4 weeks. At the end of treatment, a significant improvement was found after cathodal stimulation only in the verb generation task. No significant differences were present for verb naming among the two conditions. We hypothesize that cerebellar tDCS is a viable tool for recovery from aphasia but only when the language task, such as verb generation, also demands the activation of nonlinguistic strategies.

  13. The Effectiveness of Transcranial Direct Current Stimulation (tDCS on Working Memory in Patients with Major Depression

    Directory of Open Access Journals (Sweden)

    Mahboube Ebadi

    2017-08-01

    Full Text Available Abstract Background: The aim of this study was to evaluate the effectiveness of of transcranial direct current stimulation (tDCS on working memory in patients with major depression. Materials and Methods: The research method was quasi-experimental with pretest and post-test and follow-up with control group. The research population comprised female outpatient referrals to private psychiatric centers and psychological counseling centers in Tehran in the first half of 2016, They had received a diagnosis of depression by a psychiatrist at least once. Of these, 30 females were selected as a sample group with convenience sampling method and based on the criteria of inclusion and exclusion and were divided randomly into two groups , experimental (n = 15 and control (n = 15 group. The experimental group received transcranial direct current stimulation (tDCS in 10 sessions, While this intervention was not provided to the control group. The data were collected by N-BACK. Analysis of variance with repeated measurments was used to test the research hypothesis. Results: The results showed that transcranial direct current stimulation (tDCS had a significant effect on increasing working memory and the impact will continue to follow up. Conclusion: Therefore, this approach can be used to improve working memory in people with major depression.

  14. Transcranial magnetic stimulation-induced global propagation of transient phase resetting associated with directional information flow

    Directory of Open Access Journals (Sweden)

    Masahiro eKawasaki

    2014-03-01

    Full Text Available Electroencephalogram (EEG phase synchronization analyses can reveal large-scale communication between distant brain areas. However, it is not possible to identify the directional information flow between distant areas using conventional phase synchronization analyses. In the present study, we applied transcranial magnetic stimulation (TMS to the occipital area in subjects who were resting with their eyes closed, and analyzed the spatial propagation of transient TMS-induced phase resetting by using the transfer entropy (TE, to quantify the causal and directional flow of information. The time-frequency EEG analysis indicated that the theta (5 Hz phase locking factor (PLF reached its highest value at the distant area (the motor area in this study, with a time lag that followed the peak of the transient PLF enhancements of the TMS-targeted area at the TMS onset. PPI (phase-preservation index analyses demonstrated significant phase resetting at the TMS-targeted area and distant area. Moreover, the TE from the TMS-targeted area to the distant area increased clearly during the delay that followed TMS onset. Interestingly, the time lags were almost coincident between the PLF and TE results (152 vs. 165 ms, which provides strong evidence that the emergence of the delayed PLF reflects the causal information flow. Such tendencies were observed only in the higher-intensity TMS condition, and not in the lower-intensity or sham TMS conditions. Thus, TMS may manipulate large-scale causal relationships between brain areas in an intensity-dependent manner. We demonstrated that single-pulse TMS modulated global phase dynamics and directional information flow among synchronized brain networks. Therefore, our results suggest that single-pulse TMS can manipulate both incoming and outgoing information in the TMS-targeted area associated with functional changes.

  15. 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.

  16. Combining Transcranial Direct Current Stimulation and Tailor-Made Notched Music Training to Decrease Tinnitus-Related Distress – A Pilot Study

    Science.gov (United States)

    Teismann, Henning; Wollbrink, Andreas; Okamoto, Hidehiko; Schlaug, Gottfried; Rudack, Claudia; Pantev, Christo

    2014-01-01

    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. PMID:24587113

  17. Transcranial direct current stimulation (tDCS) for improving capacity in activities and arm function after stroke: a network meta-analysis of randomised controlled trials.

    Science.gov (United States)

    Elsner, Bernhard; Kwakkel, Gert; Kugler, Joachim; Mehrholz, Jan

    2017-09-13

    Transcranial Direct Current Stimulation (tDCS) is an emerging approach for improving capacity in activities of daily living (ADL) and upper limb function after stroke. However, it remains unclear what type of tDCS stimulation is most effective. Our aim was to give an overview of the evidence network regarding the efficacy and safety of tDCS and to estimate the effectiveness of the different stimulation types. We performed a systematic review of randomised trials using network meta-analysis (NMA), searching the following databases until 5 July 2016: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED, Web of Science, and four other databases. We included studies with adult people with stroke. We compared any kind of active tDCS (anodal, cathodal, or dual, that is applying anodal and cathodal tDCS concurrently) regarding improvement of our primary outcome of ADL capacity, versus control, after stroke. CRD42016042055. We included 26 studies with 754 participants. Our NMA showed evidence of an effect of cathodal tDCS in improving our primary outcome, that of ADL capacity (standardized mean difference, SMD = 0.42; 95% CI 0.14 to 0.70). tDCS did not improve our secondary outcome, that of arm function, measured by the Fugl-Meyer upper extremity assessment (FM-UE). There was no difference in safety between tDCS and its control interventions, measured by the number of dropouts and adverse events. Comparing different forms of tDCS shows that cathodal tDCS is the most promising treatment option to improve ADL capacity in people with stroke.

  18. 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.

  19. No effects of slow oscillatory transcranial direct current stimulation (tDCS) on sleep-dependent memory consolidation in healthy elderly subjects.

    Science.gov (United States)

    Eggert, Torsten; Dorn, Hans; Sauter, Cornelia; Nitsche, Michael A; Bajbouj, Malek; Danker-Hopfe, Heidi

    2013-11-01

    Studies in young healthy volunteers provided evidence of a beneficial impact of an anodal time-varied transcranial direct current stimulation (tDCS) during early slow wave rich sleep on declarative memory but not on procedural memory. The present study investigated whether sleep-dependent memory consolidation can also be affected by slow oscillating tDCS in a population of elderly subjects. 26 subjects (69.1 years ± 7.7 years) received bi-frontal anodal stimulation (max. current density: 0.331 mA/cm(2)) during early NREM sleep in a double-blind placebo-controlled randomized crossover study. Stimulation effects on offline consolidation were tested by using a declarative and a procedural memory task. Furthermore, sleep stages were scored, EEG power was analyzed and spindle densities were assessed. Independently from stimulation condition, performance in both memory tasks significantly decreased overnight. Stimulation revealed no significant effect on sleep-dependent memory consolidation. Verum tDCS was accompanied by significantly more time awake and significantly less NREM stage 3 sleep during five 1-min stimulation free intervals. The results of the present study are in line with other studies showing that offline consolidation during sleep varies with age and is less pronounced in the elderly than in young or middle-aged subjects. Contrary to an almost identical positive study in young adults, slow oscillatory tDCS applied to the elderly failed to show a beneficial effect on memory consolidation in the present study. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. 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.

  1. 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.

  2. The impact of anode design on fuel crossover of direct ethanol fuel cell

    Indian Academy of Sciences (India)

    advantageous owing to its low toxicity, high-energy density and renewable nature [5]. Furthermore, direct-ethanol fuel cell (DEFC) is a subset of proton exchange membrane fuel cells and retains all its benefits. The electrochemical reac- tion of DEFC, is that the ethanol is electro-oxidized at the anode and oxygen is reduced ...

  3. The impact of anode design on fuel crossover of direct ethanol fuel cell

    Indian Academy of Sciences (India)

    Fuel cell; PEM; ethanol; anode design; fuel crossover; characterization. Abstract. Direct-ethanol fuel cells (DEFCs) hold a promising future owing to its simple balance of plant operation and potential high-energy density. The significant challenges associated with it is the fuel crossover, which limits its performance and ...

  4. Taking Sides: An Integrative Review of the Impact of Laterality and Polarity on Efficacy of Therapeutic Transcranial Direct Current Stimulation for Anomia in Chronic Poststroke Aphasia

    Science.gov (United States)

    Sandars, Margaret; Cloutman, Lauren; Woollams, Anna M.

    2016-01-01

    Anomia is a frequent and persistent symptom of poststroke aphasia, resulting from damage to areas of the brain involved in language production. Cortical neuroplasticity plays a significant role in language recovery following stroke and can be facilitated by behavioral speech and language therapy. Recent research suggests that complementing therapy with neurostimulation techniques may enhance functional gains, even amongst those with chronic aphasia. The current review focuses on the use of transcranial Direct Current Stimulation (tDCS) as an adjunct to naming therapy for individuals with chronic poststroke aphasia. Our survey of the literature indicates that combining therapy with anodal (excitatory) stimulation to the left hemisphere and/or cathodal (inhibitory) stimulation to the right hemisphere can increase both naming accuracy and speed when compared to the effects of therapy alone. However, the benefits of tDCS as a complement to therapy have not been yet systematically investigated with respect to site and polarity of stimulation. Recommendations for future research to help determine optimal protocols for combined therapy and tDCS are outlined. PMID:26819777

  5. Combined transcranial direct current stimulation and home-based occupational therapy for upper limb motor impairment following intracerebral hemorrhage: a double-blind randomized controlled trial.

    Science.gov (United States)

    Mortensen, Jesper; Figlewski, Krystian; Andersen, Henning

    2016-01-01

    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). 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). Both groups improved JTT over time (p 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 impairment. It is well tolerated by patients and can easily be applied for home-based training. Larger studies with long-term follow-up are needed to further explore possible effects of tDCS in patients with ICH. Five consecutive days of tDCS combined with occupational therapy provided greater improvements in grip strength compared with occupational therapy alone. tDCS is well tolerated by patients and can easily be applied for home-based rehabilitation.

  6. Taking Sides: An Integrative Review of the Impact of Laterality and Polarity on Efficacy of Therapeutic Transcranial Direct Current Stimulation for Anomia in Chronic Poststroke Aphasia

    Directory of Open Access Journals (Sweden)

    Margaret Sandars

    2016-01-01

    Full Text Available Anomia is a frequent and persistent symptom of poststroke aphasia, resulting from damage to areas of the brain involved in language production. Cortical neuroplasticity plays a significant role in language recovery following stroke and can be facilitated by behavioral speech and language therapy. Recent research suggests that complementing therapy with neurostimulation techniques may enhance functional gains, even amongst those with chronic aphasia. The current review focuses on the use of transcranial Direct Current Stimulation (tDCS as an adjunct to naming therapy for individuals with chronic poststroke aphasia. Our survey of the literature indicates that combining therapy with anodal (excitatory stimulation to the left hemisphere and/or cathodal (inhibitory stimulation to the right hemisphere can increase both naming accuracy and speed when compared to the effects of therapy alone. However, the benefits of tDCS as a complement to therapy have not been yet systematically investigated with respect to site and polarity of stimulation. Recommendations for future research to help determine optimal protocols for combined therapy and tDCS are outlined.

  7. 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.

  8. Prefronto–cerebellar transcranial direct current stimulation improves visuospatial memory, executive functions, and neurological soft signs in patients with euthymic bipolar disorder

    Directory of Open Access Journals (Sweden)

    Minichino A

    2015-08-01

    Full Text Available Amedeo Minichino, Francesco Saverio Bersani, Laura Bernabei, Francesco Spagnoli, Lucilla Vergnani, Alessandra Corrado, Ines Taddei, Massimo Biondi, Roberto Delle Chiaie Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy Objective: The aim of the study was to improve neuropsychological functioning of euthymic patients with bipolar disorder (BD using transcranial direct current stimulation (tDCS applied to cerebellar and prefrontal cortices.Methods: Twenty-five BD outpatients underwent prefrontal (anodal and cerebellar (cathodal tDCS for 3 consecutive weeks. All participants were assessed through the Rey Complex Figure Test delay and copy and the Neurological Examination Scale at baseline and after therapy with tDCS.Results: After tDCS treatment, patients showed significant improvements in visuospatial memory tasks. Patients with worse baseline cognitive performances also showed a significant improvement in executive functioning tasks. Neurological Examination Scale total score and motor coordination subscale significantly improved.Conclusion: Prefrontal-excitatory and cerebellar-inhibitory stimulations in euthymic BD patients may lead to better neurocognitive performances. This improvement could result from the modulation of prefronto–thalamic–cerebellar circuit activity pattern, which can be disrupted in BD. Keywords: cerebellum, dorsolateral prefrontal cortex, neuropsychology, cognition 

  9. 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.

  10. Combination of Transcranial Direct Current Stimulation and Neuromuscular Electrical Stimulation Improves Gait Ability in a Patient in Chronic Stage of Stroke

    Directory of Open Access Journals (Sweden)

    Takeshi Satow

    2016-02-01

    Full Text Available Background: Walking ability is important in stroke patients to maintain daily life. Nevertheless, its improvement is limited with conventional physical therapy in chronic stage. We report the case of a chronic stroke patient showing a remarkable improvement in gait function after a new neurorehabilitation protocol using transcranial direct current stimulation (tDCS and neuromuscular electrical stimulation (NMES. Case Presentation: A 62-year-old male with left putaminal hemorrhage suffered from severe right hemiparesis. He could move by himself with a wheelchair 1 year after the ictus. Anodal tDCS at the vertex (2 mA, 20 min with NMES at the anterior tibialis muscle had been applied for 3 weeks. The Timed Up and Go test and 10-meter walk test improved after the intervention, which had been maintained for at least 1 month. Conclusion: This single case suggests the possibility that tDCS with NMES could be a new rehabilitation approach to improve the gait ability in chronic stroke patients.

  11. 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.

  12. 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.

  13. Preparation and characterization of long-lived anode catalyst for direct methanol fuel cells.

    Science.gov (United States)

    Shimazaki, Yuzuru; Kobayashi, Yoshio; Sugimasa, Masatoshi; Yamada, Shinji; Itabashi, Takeyuki; Miwa, Takao; Konno, Mikio

    2006-08-01

    Entry of direct methanol fuel cells into the market requires anode catalyst with stable activity. This paper presents a novel method for stabilizing the activity by immobilizing silica on the catalytic PtRu nanoparticles. Characterization was performed by STEM-EDX, XRD, and ICP. The silica-immobilized PtRu nanoparticles showed high and stable activity toward methanol oxidation. The activity was maintained for 1000 h in sulfuric acidic solution, while the activity of the catalyst with "bare" PtRu nanoparticles decayed after 100 h, showing high durability of the silica-immobilized PtRu nanoparticles catalyst in quasi-anodic acidic environment.

  14. Direct anodic hydrochloric acid and cathodic caustic production during water electrolysis

    OpenAIRE

    Lin, Hui-Wen; Cejudo-Mar?n, Roc?o; Jeremiasse, Adriaan W.; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

    2016-01-01

    Hydrochloric acid (HCl) and caustic (NaOH) are among the most widely used chemicals by the water industry. Direct anodic electrochemical HCl production by water electrolysis has not been successful as current commercially available electrodes are prone to chlorine formation. This study presents an innovative technology simultaneously generating HCl and NaOH from NaCl using a Mn0.84Mo0.16O2.23 oxygen evolution electrode during water electrolysis. The results showed that protons could be anodic...

  15. The performance analysis of direct methanol fuel cells with different hydrophobic anode channels

    Science.gov (United States)

    Yeh, Hung-Chun; Yang, Ruey-Jen; Luo, Win-Jet; Jiang, Jia-You; Kuan, Yean-Der; Lin, Xin-Quan

    In order to enhance the performance of the direct methanol fuel cell (DMFC), the product of CO 2 bubble has to be efficiently removed from the anode channel during the electrochemical reaction. In this study, the materials of Polymethyl Methacrylate (PMMA) with hydrophilic property and polydimethylsiloxane (PDMS) with hydrophobic property are used to form the anode cannel. The channel is fabricated through a microelectromechanical system (MEMS) manufacture process of the DMFCs. In addition, some particles with high hydrophobic properties are added into the PDMS materials in order to further reduce the hydro-resistance in the anode channel. The performance of the DMFCs is investigated under the influence of operation conditions, including operation temperature, flow rate, and methanol concentration. It is found that the performance of the DMFC, which is made of PDMS with high hydrophobic particles, can be greatly enhanced and the hydrophobic property of the particles can be unaffected by different operation conditions.

  16. Pediatric Stroke and transcranial Direct Current Stimulation: Methods for Rational Individualized Dose Optimization

    Directory of Open Access Journals (Sweden)

    Bernadette T Gillick

    2014-09-01

    Full Text Available Background- Transcranial direct current stimulation (tDCS has been investigated mainly in adults and doses may not be appropriate in pediatric applications. In perinatal stroke where potential applications are promising, rational adaptation of dosage for children remains under investigation.Objective - Construct child-specific tDCS dosing parameters through case study within a perinatal stroke tDCS safety and feasibility trial. Methods- 10-year-old subject with a diagnosis of presumed perinatal ischemic stroke and hemiparesis was identified. T1 MRI scans used to derive computerized model for current flow and electrode positions. Workflow using modeling results and consideration of dosage in previous clinical trials was incorporated. Prior Ad hoc adult montages versus de novo optimized montages provided distinct risk benefit analysis. Approximating adult dose required consideration of changes in both peak brain current flow and distribution which further tradeoff between maximizing efficacy and adding safety factors. Electrode size, position, current intensity, compliance voltage, and duration were controlled independently in this process.Results- Brain electric fields modeled and compared to values previously predicted models. Approximating conservative brain current flow patterns and intensities used in previous adult trials for comparable indications, the optimal current intensity established was 0.7 mA for 10 minutes with a tDCS C3/C4 montage. Specifically 0.7 mA produced comparable peak brain current intensity of an average adult receiving 1.0 mA. Electrode size of 5x7 cm2 with 1.0 mA and low-voltage tDCS was employed to maximize tolerability. Safety and feasibility confirmed with subject tolerating the session well and no serious adverse events.Conclusion- Rational approaches to dose customization, with steps informed by computational modeling, may improve guidance for pediatric stroke tDCS trials.

  17. Dosage considerations for transcranial direct current stimulation in children: a computational modeling study.

    Directory of Open Access Journals (Sweden)

    Sudha Kilaru Kessler

    Full Text Available Transcranial direct current stimulation (tDCS is being widely investigated in adults as a therapeutic modality for brain disorders involving abnormal cortical excitability or disordered network activity. Interest is also growing in studying tDCS in children. Limited empirical studies in children suggest that tDCS is well tolerated and may have a similar safety profile as in adults. However, in electrotherapy as in pharmacotherapy, dose selection in children requires special attention, and simple extrapolation from adult studies may be inadequate. Critical aspects of dose adjustment include 1 differences in neurophysiology and disease, and 2 variation in brain electric fields for a specified dose due to gross anatomical differences between children and adults. In this study, we used high-resolution MRI derived finite element modeling simulations of two healthy children, ages 8 years and 12 years, and three healthy adults with varying head size to compare differences in electric field intensity and distribution. Multiple conventional and high-definition tDCS montages were tested. Our results suggest that on average, children will be exposed to higher peak electrical fields for a given applied current intensity than adults, but there is likely to be overlap between adults with smaller head size and children. In addition, exposure is montage specific. Variations in peak electrical fields were seen between the two pediatric models, despite comparable head size, suggesting that the relationship between neuroanatomic factors and bioavailable current dose is not trivial. In conclusion, caution is advised in using higher tDCS doses in children until 1 further modeling studies in a larger group shed light on the range of exposure possible by applied dose and age and 2 further studies correlate bioavailable dose estimates from modeling studies with empirically tested physiologic effects, such as modulation of motor evoked potentials after stimulation.

  18. Dosage Considerations for Transcranial Direct Current Stimulation in Children: A Computational Modeling Study

    Science.gov (United States)

    Kessler, Sudha Kilaru; Minhas, Preet; Woods, Adam J.; Rosen, Alyssa; Gorman, Casey; Bikson, Marom

    2013-01-01

    Transcranial direct current stimulation (tDCS) is being widely investigated in adults as a therapeutic modality for brain disorders involving abnormal cortical excitability or disordered network activity. Interest is also growing in studying tDCS in children. Limited empirical studies in children suggest that tDCS is well tolerated and may have a similar safety profile as in adults. However, in electrotherapy as in pharmacotherapy, dose selection in children requires special attention, and simple extrapolation from adult studies may be inadequate. Critical aspects of dose adjustment include 1) differences in neurophysiology and disease, and 2) variation in brain electric fields for a specified dose due to gross anatomical differences between children and adults. In this study, we used high-resolution MRI derived finite element modeling simulations of two healthy children, ages 8 years and 12 years, and three healthy adults with varying head size to compare differences in electric field intensity and distribution. Multiple conventional and high-definition tDCS montages were tested. Our results suggest that on average, children will be exposed to higher peak electrical fields for a given applied current intensity than adults, but there is likely to be overlap between adults with smaller head size and children. In addition, exposure is montage specific. Variations in peak electrical fields were seen between the two pediatric models, despite comparable head size, suggesting that the relationship between neuroanatomic factors and bioavailable current dose is not trivial. In conclusion, caution is advised in using higher tDCS doses in children until 1) further modeling studies in a larger group shed light on the range of exposure possible by applied dose and age and 2) further studies correlate bioavailable dose estimates from modeling studies with empirically tested physiologic effects, such as modulation of motor evoked potentials after stimulation. PMID:24086698

  19. Transcranial direct current stimulation of the frontal-parietal-temporal area attenuates smoking behavior.

    Science.gov (United States)

    Meng, Zhiqiang; Liu, Chang; Yu, Chengyang; Ma, Yuanye

    2014-07-01

    Many brain regions are involved in smoking addiction (e.g. insula, ventral tegmental area, prefrontal cortex and hippocampus), and the manipulation of the activity of these brain regions can show a modification of smoking behavior. Low current transcranial direct current stimulation (tDCS) is a noninvasive way to manipulate cortical excitability, and thus brain function and associated behaviors. In this study, we examined the effects of inhibiting the frontal-parietal-temporal association area (FPT) on attention bias to smoking-related cues and smoking behavior in tobacco users. This inhibition is induced by cathodal tDCS stimulation. We tested three stimulation conditions: 1) bilateral cathodal over both sides of FPT; 2) cathodal over right FPT; and 3) sham-tDCS. Visual attention bias to smoking-related cues was evaluated using an eye tracking system. The measurement for smoking behavior was the number of daily cigarettes consumed before and after tDCS treatment. We found that, after bilateral cathodal stimulation of the FPT area, while the attention to smoking-related cues showed a decreased trend, the effects were not significantly different from sham stimulation. The daily cigarette consumption was reduced to a significant level. These effects were not seen under single cathodal tDCS or sham-tDCS. Our results show that low current tDCS of FPT area attenuates smoking cue-related attention and smoking behavior. This non-invasive brain stimulation technique, targeted at FPT areas, might be a promising method for treating smoking behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Transcranial Direct Current Stimulation: Five Important Issues We Aren’t Discussing (But Probably Should Be

    Directory of Open Access Journals (Sweden)

    Jared Cooney Horvath

    2014-01-01

    Full Text Available Transcranial Direct Current Stimulation (tDCS is a neuromodulatory device often publicized for its ability to enhance cognitive and behavioral performance. These enhancement claims, however, are predicated upon electrophysiological evidence and descriptions which are far from conclusive. In fact, a review of the literature reveals a number of important experimental and technical issues inherent with this device that are simply not being discussed in any meaningful manner. In this paper, we will consider five of these topics. The first, inter-subject variability, explores the extensive between- and within-group differences found within the tDCS literature and highlights the need to properly examine stimulatory response at the individual level. The second, intra-subject reliability, reviews the lack of data concerning tDCS response reliability over time and emphasizes the importance of this knowledge for appropriate stimulatory application. The third, sham stimulation and blinding, draws attention to the importance (yet relative lack of proper control and blinding practices in the tDCS literature. The fourth, motor and cognitive interference, highlights the often overlooked body of research that suggests typical behaviors and cognitions undertaken during or following tDCS can impair or abolish the effects of stimulation. Finally, the fifth, electric current influences, underscores several largely ignored variables (such as hair thickness and electrode attachments methods influential to tDCS electric current density and flow.Through this paper, we hope to increase awareness and start an ongoing dialogue of these important issues which speak to the efficacy, reliability, and mechanistic foundations of tDCS.

  1. Modulation of Perception or Emotion? A Scoping Review of Tinnitus Neuromodulation Using Transcranial Direct Current Stimulation.

    Science.gov (United States)

    Shekhawat, Giriraj Singh; Stinear, Cathy M; Searchfield, Grant D

    2015-10-01

    Tinnitus is the phantom perception of sound and can have negative effect on the quality of life. Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique, which can increase or decrease the cortical excitability in the brain region to which it is applied. tDCS has been used for tinnitus research since 2006. To investigate whether tDCS affects tinnitus perception, related emotion, or both, and the potential implications for tinnitus management. A scoping review was undertaken using the methods proposed by Arksey and O'Malley. After initial consideration of title relevance and reading abstracts, 15 studies were included in this review. The data from these studies were charted to investigate the impact of tDCS on tinnitus perception and emotions. tDCS results in transient suppression of tinnitus loudness and annoyance; however, it does not lead to long-term impact on tinnitus related emotion. Local stimulation of different sites of stimulation (left temporoparietal area, dorsolateral prefrontal cortex, and auditory cortex) might modulate tinnitus perception (loudness) and emotions differently; however, further research is needed to explore this hypothesis. This review has identified aspects of methodologies that require attention in upcoming tinnitus and tDCS trials to offer better insights. tDCS is an effective research tool for transient tinnitus neuromodulation. However, efforts should be invested in designing clinical trials using local and multiple sites of stimulation, optimized parameters, and objective outcome measures before it can be translated in to a clinical tool for tinnitus management. © The Author(s) 2015.

  2. Effects of Transcranial Direct Current Stimulation (tDCS) on Human Memory.

    Energy Technology Data Exchange (ETDEWEB)

    Matzen, Laura E.; Trumbo, Michael Christopher Stefan

    2014-10-01

    Training a person in a new knowledge base or skill set is extremely time consuming and costly, particularly in highly specialized domains such as the military and the intelligence community. Recent research in cognitive neuroscience has suggested that a technique called transcranial direct current stimulation (tDCS) has the potential to revolutionize training by enabling learners to acquire new skills faster, more efficiently, and more robustly (Bullard et al., 2011). In this project, we tested the effects of tDCS on two types of memory performance that are critical for learning new skills: associative memory and working memory. Associative memory is memory for the relationship between two items or events. It forms the foundation of all episodic memories, so enhancing associative memory could provide substantial benefits to the speed and robustness of learning new information. We tested the effects of tDCS on associative memory, using a real-world associative memory task: remembering the links between faces and names. Working memory refers to the amount of information that can be held in mind and processed at one time, and it forms the basis for all higher-level cognitive processing. We investigated the degree of transfer between various working memory tasks (the N-back task as a measure of verbal working memory, the rotation-span task as a measure of visuospatial working memory, and Raven's progressive matrices as a measure of fluid intelligence) in order to determine if tDCS-induced facilitation of performance is task-specific or general.

  3. Transcranial direct current stimulation versus user training on improving online myoelectric control for amputees

    Science.gov (United States)

    Pan, Lizhi; Zhang, Dingguo; Jiang, Ning; Sheng, Xinjun; Zhu, Xiangyang

    2017-08-01

    Objective. Transcranial direct current stimulation (tDCS) and user training (UT) are two types of methods to improve myoelectric control performance for amputees. In this study, we compared the independent effect between tDCS and UT, and investigated the combined effect of tDCS and UT. Approach. An online paradigm of simultaneous and proportional control (SPC) based on electromyography (EMG) was adopted. The proposed experiments were conducted on six naïve unilateral trans-radial amputees. The subjects each received three types of 20 min interventions: active tDCS with motor training (tDCS  +  UT), active tDCS with quiet sitting (tDCS), and sham tDCS with motor training (UT). The interventions were applied at one week intervals in a randomized order. The subjects performed online control of a feedback arrow with two degrees of freedom (DoFs) to accomplish target reaching motor tasks in pre-sessions and post-sessions. We compared the performance, measured by completion rate, completion time, and efficiency coefficient, between pre-sessions and post-sessions. Main results. The results showed that the intervention tDCS  +  UT and tDCS significantly improved the online SPC performance (i.e. improved the completion rate; reduced the completion time; and improved the efficiency coefficient), while intervention UT did not significantly change the performance. The results also showed that the online SPC performance after intervention tDCS  +  UT and tDCS was not significantly different, but both were significantly better than that after intervention UT. Significance. tDCS could be an effective intervention to improve the online SPC performance in a short time.

  4. 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

  5. Mixed phase Pt-Ru catalyst for direct methanol fuel cell anode by flame aerosol synthesis

    DEFF Research Database (Denmark)

    Chakraborty, Debasish; Bischoff, H.; Chorkendorff, Ib

    2005-01-01

    A spray-flame aerosol catalyzation technique was studied for producing Pt-Ru anode electrodes for the direct methanol fuel cell. Catalysts were produced as aerosol nanoparticles in a spray-flame reactor and deposited directly as a thin layer on the gas diffusion layer. The as-prepared catalyst......Ru1/Vulcan carbon. The kinetics of methanol oxidation on the mixed phase catalyst was also explored by electrochemical impedance spectroscopy. (c) 2005 The Electrochemical Society....

  6. Effects of Nafion loading in anode catalyst inks on the miniature direct formic acid fuel cell

    Science.gov (United States)

    Morgan, Robert D.; Haan, John L.; Masel, Richard I.

    Nafion, within the anode and cathode catalyst layers, plays a large role in the performance of fuel cells, especially during the operation of the direct formic acid fuel cell (DFAFC). Nafion affects the proton transfer in the catalyst layers of the fuel cell, and studies presented here show the effects of three different Nafion loadings, 10 wt.%, 30 wt.% and 50 wt.%. Short term voltage-current measurements using the three different loadings show that 30 wt.% Nafion loading in the anode shows the best performance in the miniature, passive DFAFC. Nafion also serves as a binder to help hold the catalyst nanoparticles onto the proton exchange membrane (PEM). The DFAFC anode temporarily needs to be regenerated by raising the anode potential to around 0.8 V vs. RHE to oxidize CO bound to the surface, but the Pourbaix diagram predicts that Pd will corrode at these potentials. We found that an anode loading of 30 wt.% Nafion showed the best stability, of the three Nafion loadings chosen, for reducing the amount of loss of electrochemically active area due to high regeneration potentials. Only 58% of the area was lost after 600 potential cycles in formic acid compared to 96 and 99% for 10 wt.% and 50 wt.% loadings, respectively. Lastly we present cyclic voltammetry data that suggest that the Nafion adds to the production of CO during oxidation of formic acid for 12 h at 0.3 V vs. RHE. The resulting data showed that an increase in CO coverage was observed with increasing Nafion content in the anode catalyst layer.

  7. Integrated anode structure for passive direct methanol fuel cells with neat methanol operation

    Science.gov (United States)

    Wu, Huijuan; Zhang, Haifeng; Chen, Peng; Guo, Jing; Yuan, Ting; Zheng, Junwei; Yang, Hui

    2014-02-01

    A microporous titanium plate based integrated anode structure (Ti-IAS) suitable for passive direct methanol fuel cells (DMFCs) fueled with neat methanol is reported. This anode structure incorporates a porous titanium plate as a methanol mass transfer barrier and current collector, pervaporation film for passively vaporizing methanol, vaporous methanol cavity for evenly distributing fuel, and channels for carbon dioxide venting. With the effective control of methanol delivery rate, the Ti-IAS based DMFC allows the direct use of neat methanol as the fuel source. In the meantime, the required water for methanol-oxidation reaction at the anode can also be fully recovered from the cathode with the help of the highly hydrophobic microporous layer in the cathode. DMFCs incorporating this new anode structure exhibit a power density as high as 40 mW cm-2 and a high volumetric energy density of 489 Wh L-1 operating with neat methanol and at 25 °C. Importantly, no obvious performance degradation of the passive DMFC system is observed after more than 90 h of continuous operation. The experimental results reveal that the compact DMFC based on the Ti-IAS exhibits a substantial potential as power sources for portable applications.

  8. Liquid Tin Anode Direct Coal Fuel Cell Final Program Report

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Thomas

    2012-01-26

    This SBIR program will result in improved LTA cell technology which is the fundamental building block of the Direct Coal ECL concept. As described below, ECL can make enormous efficiency and cost contributions to utility scale coal power. This program will improve LTA cells for small scale power generation. As described in the Commercialization section, there are important intermediate military and commercial markets for LTA generators that will provide an important bridge to the coal power application. The specific technical information from this program relating to YSZ electrolyte durability will be broadly applicable SOFC developers working on coal based SOFC generally. This is an area about which very little is currently known and will be critical for successfully applying fuel cells to coal power generation.

  9. Notes on Human Trials of Transcranial Direct Current Stimulation between 1960 and 1998

    Science.gov (United States)

    Esmaeilpour, Zeinab; Schestatsky, Pedro; Bikson, Marom; Brunoni, André R.; Pellegrinelli, Ada; Piovesan, Fernanda X.; Santos, Mariana M. S. A.; Menezes, Renata B.; Fregni, Felipe

    2017-01-01

    Background: Transcranial direct current stimulation (tDCS) is investigated to modulate neuronal function including cognitive neuroscience and neuropsychiatric therapies. While cases of human stimulation with rudimentary batteries date back more than 200 years, clinical trials with current controlled stimulation were published intermittently since the 1960s. The modern era of tDCS only started after 1998. Objectives: To review methods and outcomes of tDCS studies from old literature (between 1960 and 1998) with intention of providing new insight for ongoing tDCS trials and development of tDCS protocols especially for the purpose of treatment. Methods: Articles were identified through a search in PubMed and through the reference list from its selected articles. We included only non-invasive human studies that provided controlled direct current and were written in English, French, Spanish or Portuguese before the year of 1998, the date in which modern stimulation paradigms were implemented. Results: Fifteen articles met our criteria. The majority were small-randomized controlled clinical trials that enrolled a mean of approximately 26 subjects (Phase II studies). Most of the studies (around 83%) assessed the role of tDCS in the treatment of psychiatric conditions, in which the main outcomes were measured by means of behavioral scales and clinical observation, but the diagnostic precision and the quality of outcome monitoring, including adverse events, were deficient by modern standards. Compared to modern tDCS dose, the stimulation intensities used (0.1–1 mA) were lower, however as the electrodes were typically smaller (e.g., 1.26 cm2), the average electrode current density (0.2 mA/cm2) was approximately 4× higher. The number of sessions ranged from one to 120 (median 14). Notably, the stimulation session durations of several minutes to 11 h (median 4.5 h) could markedly exceed modern tDCS protocols. Twelve studies out of 15 showed positive results. Only mild side

  10. Single-step direct fabrication of pillar-on-pore hybrid nanostructures in anodizing aluminum for superior superhydrophobic efficiency.

    Science.gov (United States)

    Jeong, Chanyoung; Choi, Chang-Hwan

    2012-02-01

    Conventional electrochemical anodizing processes of metals such as aluminum typically produce planar and homogeneous nanopore structures. If hydrophobically treated, such 2D planar and interconnected pore structures typically result in lower contact angle and larger contact angle hysteresis than 3D disconnected pillar structures and, hence, exhibit inferior superhydrophobic efficiency. In this study, we demonstrate for the first time that the anodizing parameters can be engineered to design novel pillar-on-pore (POP) hybrid nanostructures directly in a simple one-step fabrication process so that superior surface superhydrophobicity can also be realized effectively from the electrochemical anodization process. On the basis of the characteristic of forming a self-ordered porous morphology in a hexagonal array, the modulation of anodizing voltage and duration enabled the formulation of the hybrid-type nanostructures having controlled pillar morphology on top of a porous layer in both mild and hard anodization modes. The hybrid nanostructures of the anodized metal oxide layer initially enhanced the surface hydrophilicity significantly (i.e., superhydrophilic). However, after a hydrophobic monolayer coating, such hybrid nanostructures then showed superior superhydrophobic nonwetting properties not attainable by the plain nanoporous surfaces produced by conventional anodization conditions. The well-regulated anodization process suggests that electrochemical anodizing can expand its usefulness and efficacy to render various metallic substrates with great superhydrophilicity or -hydrophobicity by directly realizing pillar-like structures on top of a self-ordered nanoporous array through a simple one-step fabrication procedure.

  11. Direct Utilization of Liquid Fuels in SOFC for Portable Applications: Challenges for the Selection of Alternative Anodes

    Directory of Open Access Journals (Sweden)

    Massimiliano Cimenti

    2009-06-01

    Full Text Available Solid oxide fuel cells (SOFC have the advantage of being able to operate with fuels other than hydrogen. In particular, liquid fuels are especially attractive for powering portable applications such as small power generators or auxiliary power units, in which case the direct utilization of the fuel would be convenient. Although liquid fuels are easier to handle and transport than hydrogen, their direct use in SOFC can lead to anode deactivation due to carbon formation, especially on traditional nickel/yttria stabilized zirconia (Ni/YSZ anodes. Significant advances have been made in anodic materials that are resistant to carbon formation but often these materials are less electrochemically active than Ni/YSZ. In this review the challenges of using liquid fuels directly in SOFC, in terms of gas-phase and catalytic reactions within the anode chamber, will be discussed and the alternative anode materials so far investigated will be compared.

  12. Transcranial Direct Current Stimulation combined with treadmill training in the subacute phase following stroke: case series

    DEFF Research Database (Denmark)

    Figlewski, Krystian; Nielsen, Jørgen Feldbæk; Blicher, Jakob

    anodal tDCS. Aims: to evaluate the feasibility of anodal tDCS with body weight support treadmill training (BWSTT) in the subacute stroke patients. Methods Four subjects (Table 1.) participated in BWSTT coupled with anodal tDCS thrice per week for 4 weeks. Subjects were included within 14 days from stroke......Background Stroke is a common cause of gait impairment and regaining a normal gait is a major target in stroke rehabilitation. To facilitate motor recovery after stroke, a variety of experimental approaches have been tested. Recent developments include non-invasive brain stimulation techniques...

  13. Direct anodic hydrochloric acid and cathodic caustic production during water electrolysis

    Science.gov (United States)

    Lin, Hui-Wen; Cejudo-Marín, Rocío; Jeremiasse, Adriaan W.; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

    2016-02-01

    Hydrochloric acid (HCl) and caustic (NaOH) are among the most widely used chemicals by the water industry. Direct anodic electrochemical HCl production by water electrolysis has not been successful as current commercially available electrodes are prone to chlorine formation. This study presents an innovative technology simultaneously generating HCl and NaOH from NaCl using a Mn0.84Mo0.16O2.23 oxygen evolution electrode during water electrolysis. The results showed that protons could be anodically generated at a high Coulombic efficiency (i.e. ≥ 95%) with chlorine formation accounting for 3 ~ 5% of the charge supplied. HCl was anodically produced at moderate strengths at a CE of 65 ± 4% together with a CE of 89 ± 1% for cathodic caustic production. The reduction in CE for HCl generation was caused by proton cross-over from the anode to the middle compartment. Overall, this study showed the potential of simultaneous HCl and NaOH generation from NaCl and represents a major step forward for the water industry towards on-site production of HCl and NaOH. In this study, artificial brine was used as a source of sodium and chloride ions. In theory, artificial brine could be replaced by saline waste streams such as Reverse Osmosis Concentrate (ROC), turning ROC into a valuable resource.

  14. 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

  15. A systematic review on reporting and assessment of adverse effects associated with transcranial direct current stimulation.

    Science.gov (United States)

    Brunoni, Andre Russowsky; Amadera, Joao; Berbel, Bruna; Volz, Magdalena Sarah; Rizzerio, Brenno Gomes; Fregni, Felipe

    2011-09-01

    Transcranial direct current stimulation (tDCS) is a non-invasive method of brain stimulation that has been intensively investigated in clinical and cognitive neuroscience. Although the general impression is that tDCS is a safe technique with mild and transient adverse effects (AEs), human data on safety and tolerability are largely provided from single-session studies in healthy volunteers. In addition the frequency of AEs and its relationship with clinical variables is unknown. With the aim of assessing tDCS safety in different conditions and study designs, we performed a systematic review and meta-analysis of tDCS clinical trials. We assessed Medline and other databases and reference lists from retrieved articles, searching for articles from 1998 (first trial with contemporary tDCS parameters) to August 2010. Animal studies, review articles and studies assessing other neuromodulatory techniques were excluded. According to our eligibility criteria, 209 studies (from 172 articles) were identified. One hundred and seventeen studies (56%) mentioned AEs in the report. Of these studies, 74 (63%) reported at least one AE and only eight studies quantified AEs systematically. In the subsample reporting AEs, the most common were, for active vs. sham tDCS group, itching (39.3% vs. 32.9%, p>0.05), tingling (22.2% vs. 18.3%, p>0.05), headache (14.8% vs. 16.2%, p>0.05), burning sensation (8.7% vs. 10%, p>0.05) and discomfort (10.4% vs. 13.4%, p>0.05). Meta-analytical techniques could be applied in only eight studies for itching, but no definite results could be obtained due to between-study heterogeneity and low number of studies. Our results suggested that some AEs such as itching and tingling were more frequent in the tDCS active group, although this was not statistically significant. Although results suggest that tDCS is associated with mild AEs only, we identified a selective reporting bias for reporting, assessing and publishing AEs of tDCS that hinders further

  16. Safety and feasibility of transcranial direct current stimulation in pediatric hemiparesis: randomized controlled preliminary study.

    Science.gov (United States)

    Gillick, Bernadette T; Feyma, Tim; Menk, Jeremiah; Usset, Michelle; Vaith, Amy; Wood, Teddi Jean; Worthington, Rebecca; Krach, Linda E

    2015-03-01

    Transcranial direct current stimulation (tDCS) is a form of noninvasive brain stimulation that has shown improved adult stroke outcomes. Applying tDCS in children with congenital hemiparesis has not yet been explored. The primary objective of this study was to explore the safety and feasibility of single-session tDCS through an adverse events profile and symptom assessment within a double-blind, randomized placebo-controlled preliminary study in children with congenital hemiparesis. A secondary objective was to assess the stability of hand and cognitive function. A double-blind, randomized placebo-controlled pretest/posttest/follow-up study was conducted. The study was conducted in a university pediatric research laboratory. Thirteen children, ages 7 to 18 years, with congenital hemiparesis participated. Adverse events/safety assessment and hand function were measured. Participants were randomly assigned to either an intervention group or a control group, with safety and functional assessments at pretest, at posttest on the same day, and at a 1-week follow-up session. An intervention of 10 minutes of 0.7 mA tDCS was applied to bilateral primary motor cortices. The tDCS intervention was considered safe if there was no individual decline of 25% or group decline of 2 standard deviations for motor evoked potentials (MEPs) and behavioral data and no report of adverse events. No major adverse events were found, including no seizures. Two participants did not complete the study due to lack of MEP and discomfort. For the 11 participants who completed the study, group differences in MEPs and behavioral data did not exceed 2 standard deviations in those who received the tDCS (n=5) and those in the control group (n=6). The study was completed without the need for stopping per medical monitor and biostatisticial analysis. A limitation of the study was the small sample size, with data available for 11 participants. Based on the results of this study, tDCS appears to be safe

  17. Transcranial Direct Current Stimulation in Mesial Temporal Lobe Epilepsy and Hippocampal Sclerosis.

    Science.gov (United States)

    San-Juan, Daniel; Espinoza López, Dulce Anabel; Vázquez Gregorio, Rafael; Trenado, Carlos; Fernández-González Aragón, Maricarmen; Morales-Quezada, León; Hernandez Ruiz, Axel; Hernandez-González, Flavio; Alcaraz-Guzmán, Alejandro; Anschel, David J; Fregni, Felipe

    Transcranial direct current stimulation (tDCS) has been evaluated in medication refractory epilepsy patients. The results have been inconclusive and protocols have varied between studies. To evaluate the safety and efficacy of two protocols of tDCS in adult patients with mesial temporal lobe epilepsy and hippocampal sclerosis (MTLE-HS). This is a randomized placebo-controlled, double-blinded clinical trial, with 3 arms, 3 sessions, 5 sessions and placebo stimulation. Frequency of seizures (SZs), interictal epileptiform discharges (IEDs) and adverse effects (AEs) were registered before and after treatment, and at 30 and 60 days follow-up. Descriptive statistics, k-related samples, Friedman's test, and relative risk (RR) estimation were used for analysis. We included twenty-eight subjects (3d n = 12, 5d n = 8, placebo n = 8), 16/28 (57%) men, age 37.8(±10.9) years old. There was a significant reduction of the frequency of SZs at one (p = 0.001) and two (p = 0.0001) months following cathodal tDCS compared to baseline in the 3 arms (p = 0.0001). The mean reduction of SZ frequency at two months in both active groups was significantly higher than placebo (-48% vs. -6.25%, p < 0.008). At 3 days (-43.4% vs. -6.25%, p < 0.007) and 5 days (-54.6% vs. -6.25%, p < 0.010) individual groups showed a greater reduction of SZs. A significant IED reduction effect was found between baseline and immediately after interventions (p = 0.041) in all groups. Side effects were minor. Cathodal tDCS technique of 3 and 5 sessions decreased the frequency of SZs and IEDs (between baseline and immediately post-tDCS) in adult patients with MTLE-HS compared to placebo tDCS. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. High-performance alkaline direct methanol fuel cell using a nitrogen-postdoped anode.

    Science.gov (United States)

    Joghee, Prabhuram; Pylypenko, Svitlana; Wood, Kevin; Bender, Guido; O'Hayre, Ryan

    2014-07-01

    A commercial PtRu/C catalyst postdoped with nitrogen demonstrates a significantly higher performance (~10-20% improvement) in the anode of an alkaline direct methanol fuel cell than an unmodified commercial PtRu/C catalyst control. The enhanced performance shown herein is attributed at least partially to the increased electrochemical surface area of the PtRu/C after postdoping with nitrogen. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Direct electrodeposition of Cu2Sb for lithium-ion battery anodes.

    Science.gov (United States)

    Mosby, James M; Prieto, Amy L

    2008-08-13

    We describe the direct single potential electrodeposition of crystalline Cu2Sb, a promising anode material for lithium-ion batteries, from aqueous solutions at room temperature. The use of citric acid as a complexing agent increases the solubility of antimony salts and shifts the reduction potentials of copper and antimony toward each other, enabling the direct deposition of the intermetallic compound at pH 6. Electrodeposition of Cu2Sb directly onto conducting substrates represents a facile synthetic method for the synthesis of high quality samples with excellent electrical contact to a substrate, which is critical for further battery testing.

  20. Predicting the behavioural impact of transcranial direct current stimulation: issues and limitations

    Directory of Open Access Journals (Sweden)

    Archy Otto De Berker

    2013-10-01

    Full Text Available The transcranial application of weak currents to the human brain has enjoyed a decade of success, providing a simple and powerful tool for non-invasively altering human brain function. However, our understanding of current delivery and its impact upon neural circuitry leaves much to be desired. We argue that the credibility of conclusions drawn with tDCS is contingent upon realistic explanations of how tDCS works, and that our present understanding of tDCS limits the technique’s use to localize function in the human brain. We outline two central issues where progress is required: the localization of currents, and predicting their functional consequence. We encourage experimenters to eschew simplistic explanations of mechanisms of transcranial current stimulation. We suggest the use of individualized current modelling, together with computational neurostimulation to inform mechanistic frameworks in which to interpret the physiological impact of tDCS. We hope that through mechanistically richer descriptions of current flow and action, insight into the biological processes by which transcranial currents influence behaviour can be gained, leading to more effective stimulation protocols and empowering conclusions drawn with tDCS.

  1. Ag as an alternative for Ni in direct hydrocarbon SOFC anodes

    Energy Technology Data Exchange (ETDEWEB)

    Cantos-Gomez, A.; Van Duijn, J. [Instituto de Energias Renovables, Universidad de Castilla La Mancha, Paseo de la Investigacion 1, 02006 Albacete (Spain); Ruiz-Bustos, R. [Instituto de Energias Renovables, Parque Cientifico y Tecnologico de Albacete, Paseo de la Investigacion 1, 02006 Albacete (Spain)

    2011-02-15

    Ag has been shown to be a good metal for SOFC anode cermets using CO fuel. Here we have expanded on the work reported by testing Ag-YSZ cermets against different hydrocarbon based fuel (H{sub 2} and CH{sub 4}). This study shows that while Ag is a good current collector, it alone does not have the required catalytic activity for the direct oxidation of hydrocarbon based fuels needed to be used in SOFC anodes. As such an additional catalytic material (e.g. CeO{sub 2}) needs to be present when using fuels other then CO. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. 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.

  3. Low-Pt-Content Anode Catalyst for Direct Methanol Fuel Cells

    Science.gov (United States)

    Narayanan, Sekharipuram; Whitacre, Jay

    2008-01-01

    Combinatorial experiments have led to the discovery that a nanophase alloy of Pt, Ru, Ni, and Zr is effective as an anode catalyst material for direct methanol fuel cells. This discovery has practical significance in that the electronic current densities achievable by use of this alloy are comparable or larger than those obtained by use of prior Pt/Ru catalyst alloys containing greater amounts of Pt. Heretofore, the high cost of Pt has impeded the commercialization of direct methanol fuel cells. By making it possible to obtain a given level of performance at reduced Pt content (and, hence, lower cost), the discovery may lead to reduction of the economic impediment to commercialization.

  4. Flexible graphite-based integrated anode plate for direct methanol fuel cells at high methanol feed concentration

    Science.gov (United States)

    Zhang, HaiFeng; Hsing, I.-Ming

    An integrated anode plate suitable for operating direct methanol fuel cells (DMFCs) at a high methanol feed concentration is reported. This anode structure which was made of flexible graphite materials not only provides dual role of liquid diffusion layer and flow field plate, but also serves as a methanol blocker by decreasing methanol flux to the interface of catalyst and membrane electrolyte. DMFCs incorporating this new anode structure exhibited a much higher open circuit voltage (OCV) (∼0.51 V) than that (∼0.42 V) of a conventional DMFC at a 10 M methanol feed. Cell polarization data show that this new anode structure significantly improves the cell performance at high methanol concentration scenarios (e.g. 12 M or above). Moreover, this new design greatly simplifies the anode structure and offers a promising approach in running passive-mode DMFC at high methanol feed concentrations.

  5. Ventral medial prefrontal cortex (vmPFC) as a target of the dorsolateral prefrontal modulation by transcranial direct current stimulation (tDCS) in drug addiction.

    Science.gov (United States)

    Nakamura-Palacios, Ester Miyuki; Lopes, Isabela Bittencourt Coutinho; Souza, Rodolpho Albuquerque; Klauss, Jaisa; Batista, Edson Kruger; Conti, Catarine Lima; Moscon, Janine Andrade; de Souza, Rodrigo Stênio Moll

    2016-10-01

    Here, we report some electrophysiologic and imaging effects of the transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (dlPFC) in drug addiction, notably in alcohol and crack-cocaine dependence. The low resolution electromagnetic tomography (LORETA) analysis obtained through event-related potentials (ERPs) under drug-related cues, more specifically in its P3 segment (300-500 ms) in both, alcoholics and crack-cocaine users, showed that the ventral medial prefrontal cortex (vmPFC) was the brain area with the largest change towards increasing activation under drug-related cues in those subjects that kept abstinence during and after the treatment with bilateral tDCS (2 mA, 35 cm(2), cathodal left and anodal right) over dlPFC, applied repetitively (five daily sessions). In an additional study in crack-cocaine, which showed craving decreases after repetitive bilateral tDCS, we examined data originating from diffusion tensor imaging (DTI), and we found increased DTI parameters in the left connection between vmPFC and nucleus accumbens (NAcc), such as the number of voxels, fractional anisotropy (FA) and apparent diffusion coefficient (ADC), in tDCS-treated crack-cocaine users when compared to the sham-tDCS group. This increasing of DTI parameters was significantly correlated with craving decreasing after the repetitive tDCS. The vmPFC relates to the control of drug seeking, possibly by extinguishing this behavior. In our studies, the bilateral dlPFC tDCS reduced relapses and craving to the drug use, and increased the vmPFC activation under drug cues, which may be of a great importance in the control of drug use in drug addiction.

  6. Transcranial Direct Current Stimulation Over the Right Frontal Inferior Cortex Decreases Neural Activity Needed to Achieve Inhibition: A Double-Blind ERP Study in a Male Population.

    Science.gov (United States)

    Campanella, Salvatore; Schroder, Elisa; Monnart, Aurore; Vanderhasselt, Marie-Anne; Duprat, Romain; Rabijns, Mark; Kornreich, Charles; Verbanck, Paul; Baeken, Chris

    2017-05-01

    Inhibitory control refers to the ability to inhibit an action once it has been initiated. Impaired inhibitory control plays a key role in triggering relapse in some pathological states, such as addictions. Therefore, a major challenge of current research is to establish new methods to strengthen inhibitory control in these "high-risk" populations. In this attempt, the right inferior frontal cortex (rIFC), a neural correlate crucial for inhibitory control, was modulated using transcranial direct current stimulation (tDCS). Healthy participants (n = 31) were presented with a "Go/No-go" task, a well-known paradigm to measure inhibitory control. During this task, an event-related potential (ERP) recording (T1; 32 channels) was performed. One subgroup (n = 15) was randomly assigned to a condition with tDCS (anodal electrode was placed on the rIFC and the cathodal on the neck); and the other group (n = 16) to a condition with sham (placebo) tDCS. After one 20- minute neuromodulation session, all participants were confronted again with the same ERP Go/No-go task (T2). To ensure that potential tDCS effects were specific to inhibition, ERPs to a face-detection task were also recorded at T1 and T2 in both subgroups. The rate of commission errors on the Go/No-go task was similar between T1 and T2 in both neuromodulation groups. However, the amplitude of the P3d component, indexing the inhibition function per se, was reduced at T2 as compared with T1. This effect was specific for participants in the tDCS (and not sham) condition for correctly inhibited trials. No difference in the P3 component was observable between both subgroups at T1 and T2 for the face detection task. Overall, the present data indicate that boosting the rIFC specifically enhances inhibitory skills by decreasing the neural activity needed to correctly inhibit a response.

  7. Study design for the fostering eating after stroke with transcranial direct current stimulation trial: a randomized controlled intervention for improving Dysphagia after acute ischemic stroke.

    Science.gov (United States)

    Marchina, Sarah; Schlaug, Gottfried; Kumar, Sandeep

    2015-03-01

    Dysphagia is a major stroke complication but lacks effective therapy that can promote recovery. Noninvasive brain stimulation with and without peripheral sensorimotor activities may be an attractive treatment option for swallowing recovery but has not been systematically investigated in the stroke population. This article describes the study design of the first prospective, single-center, double-blinded trial of anodal versus sham transcranial direct current stimulation (tDCS) used in combination with swallowing exercises in patients with dysphagia from an acute ischemic stroke. The aim of this study is to gather safety data on cumulative sessions of tDCS in acute-subacute phases of stroke, obtain information about effects of this intervention on important physiologic and clinically relevant swallowing parameters, and examine possible dose effects. Ninety-nine consecutive patients with dysphagia from an acute unilateral hemispheric infarction with a Penetration and Aspiration Scale (PAS) score of 4 or more and without other confounding reasons for dysphagia will be enrolled at a single tertiary care center. Subjects will be randomized to either a high or low dose tDCS or a sham group and will undergo 10 sessions over 5 consecutive days concomitantly with effortful swallowing maneuvers. The main efficacy measures are a change in the PAS score before and after treatment; the main safety measures are mortality, seizures, neurologic, motor, and swallowing deterioration. The knowledge gained from this study will help plan a larger confirmatory trial for treating stroke-related dysphagia and advance our understanding of important covariates influencing swallowing recovery and response to the proposed intervention. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  8. 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

  9. 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.

  10. 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

  11. 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

  12. The critical role of cognitive-based trait differences in transcranial direct current stimulation (tDCS) suppression of food craving and eating in frank obesity.

    Science.gov (United States)

    Ray, Mary Katherine; Sylvester, Maria D; Osborn, Lauren; Helms, Joel; Turan, Bulent; Burgess, Emilee E; Boggiano, Mary M

    2017-09-01

    Obesity remains a major public health concern and novel treatments are needed. Transcranial direct current stimulation (tDCS) is a neuromodulation technique shown to reduce food craving and consumption, especially when targeting the dorsolateral prefrontal cortex (DLPFC) with a right anode/left cathode electrode montage. Despite the implications to treat frank (non-bingeeating) obesity, no study has tested the right anode/left cathode montage in this population. Additionally, most tDCS appetite studies have not controlled for differences in traits under DLPFC control that may influence how well one responds to tDCS. Hence, N = 18 (10F/8M) adults with frank obesity completed the Dutch Eating Behavior Questionnaire-Restraint and Barratt Impulsiveness Scale, and received 20 min of 2 mA active tDCS and control tDCS session. Craving and eating was assessed at both sessions with a food photo "wanting" test and in-lab measures of total, preferred, and less-preferred kilocalories consumed of three highly palatable snack foods. While main effects of tDCS vs. control were not found, significant differences emerged when trait scores were controlled. tDCS reduced food craving in females with lower attention-type impulsiveness (p = 0.047), reduced preferred-food consumption in males with lower intent to restrict calories (p = 0.024), and reduced total food consumption in males with higher non-planning-type impulsiveness (p = 0.009) compared to control tDCS. This is the first study to find significant reductions in food craving and consumption in a sample with frank obesity using the most popular tDCS montage in appetite studies. The results also highlight the cognitive-based heterogeneity of individuals with obesity and the importance of considering these differences when evaluating the efficacy of DLPFC-targeted tDCS in future studies aimed at treating obesity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Causal Evidence for a Mechanism of Semantic Integration in the Angular Gyrus as Revealed by High-Definition Transcranial Direct Current Stimulation.

    Science.gov (United States)

    Price, Amy Rose; Peelle, Jonathan E; Bonner, Michael F; Grossman, Murray; Hamilton, Roy H

    2016-03-30

    A defining aspect of human cognition is the ability to integrate conceptual information into complex semantic combinations. For example, we can comprehend "plaid" and "jacket" as individual concepts, but we can also effortlessly combine these concepts to form the semantic representation of "plaid jacket." Many neuroanatomic models of semantic memory propose that heteromodal cortical hubs integrate distributed semantic features into coherent representations. However, little work has specifically examined these proposed integrative mechanisms and the causal role of these regions in semantic integration. Here, we test the hypothesis that the angular gyrus (AG) is critical for integrating semantic information by applying high-definition transcranial direct current stimulation (tDCS) to an fMRI-guided region-of-interest in the left AG. We found that anodal stimulation to the left AG modulated semantic integration but had no effect on a letter-string control task. Specifically, anodal stimulation to the left AG resulted in faster comprehension of semantically meaningful combinations like "tiny radish" relative to non-meaningful combinations, such as "fast blueberry," when compared to the effects observed during sham stimulation and stimulation to a right-hemisphere control brain region. Moreover, the size of the effect from brain stimulation correlated with the degree of semantic coherence between the word pairs. These findings demonstrate that the left AG plays a causal role in the integration of lexical-semantic information, and that high-definition tDCS to an associative cortical hub can selectively modulate integrative processes in semantic memory. A major goal of neuroscience is to understand the neural basis of behaviors that are fundamental to human intelligence. One essential behavior is the ability to integrate conceptual knowledge from semantic memory, allowing us to construct an almost unlimited number of complex concepts from a limited set of basic

  14. Chemically tuned anode with tailored aqueous hydrocarbon binder for direct methanol fuel cells.

    Science.gov (United States)

    Lee, Chang Hyun; Lee, So Young; Lee, Young Moo; McGrath, James E

    2009-07-21

    An anode for direct methanol fuel cells was chemically tuned by tailoring an aqueous hydrocarbon catalyst (SPI-BT) binder instead of using a conventional perfluorinated sulfonic acid ionomer (PFSI). SPI-BT designed in triethylamine salt form showed lower proton conductivity than PFSI, but it was stable in the catalyst ink forming the aqueous colloids. The aqueous colloidal particle size of SPI-BT was much smaller than that of PFSI. The small SPI-BT colloidal particles contributed to forming small catalyst agglomerates and simultaneously reducing their pore volume. Consequently, the high filling level of binders in the pores, where Pt-Ru catalysts are mainly located on the wall and physically interconnected, resulted in increased electrochemical active surface area of the anode, leading to high catalyst utilization. In addition, the chemical affinity between the SPI-BT binder and the membrane material derived from their similar chemical structure induced a stable interface on the membrane-electrode assembly (MEA) and showed low electric resistance. Upon adding SPI-BT, the synergistic effect of high catalyst utilization, improved mass transfer behavior to Pt-Ru catalyst, and low interfacial resistance of MEA became greater than the influence of reduced proton conductivity in the electrochemical performance of single cells. The electrochemical performance of MEAs with SPI-BT anode was enhanced to almost the same degree or somewhat higher than that with PFSI at 90 degrees C.

  15. Modulating brain mechanisms resolving lexico-semantic Interference during word production: A transcranial direct current stimulation study.

    Science.gov (United States)

    Henseler, Ilona; Mädebach, Andreas; Kotz, Sonja A; Jescheniak, Jörg D

    2014-07-01

    The aim of the current study was to shed further light on control processes that shape semantic access and selection during speech production. These processes have been linked to differential cortical activation in the left inferior frontal gyrus (IFG) and the left middle temporal gyrus (MTG); however, the particular function of these regions is not yet completely elucidated. We applied transcranial direct current stimulation to the left IFG and the left MTG (or sham stimulation) while participants named pictures in the presence of associatively related, categorically related, or unrelated distractor words. This direct modulation of target regions can help to better delineate the functional role of these regions in lexico-semantic selection. Independent of stimulation, the data show interference (i.e., longer naming latencies) with categorically related distractors and facilitation (i.e., shorter naming latencies) with associatively related distractors. Importantly, stimulation location interacted with the associative effect. Whereas the semantic interference effect did not differ between IFG, MTG, and sham stimulations, the associative facilitation effect was diminished under MTG stimulation. Analyses of latency distributions suggest this pattern to result from a response reversal. Associative facilitation occurred for faster responses, whereas associative interference resulted in slower responses under MTG stimulation. This reduction of the associative facilitation effect under transcranial direct current stimulation may be caused by an unspecific overactivation in the lexicon or by promoting competition among associatively related representations. Taken together, the results suggest that the MTG is especially involved in the processes underlying associative facilitation and that semantic interference and associative facilitation are linked to differential activation in the brain.

  16. The role of language in multi-dimensional categorization: evidence from transcranial direct current stimulation and exposure to verbal labels.

    Science.gov (United States)

    Perry, Lynn K; Lupyan, Gary

    2014-08-01

    Human concepts differ in their dimensionality. Some, like green-things, require representing one dimension while abstracting over many others. Others, like bird, have higher dimensionality due to numerous category-relevant properties (feathers, two-legs). Converging evidence points to the importance of verbal labels for forming low-dimensional categories. We examined the role of verbal labels in categorization by (1) using transcranial direct current stimulation over Wernicke's area (2) providing explicit verbal labels during a category learning task. We trained participants on a novel perceptual categorization task in which categories could be distinguished by either a uni- or bi-dimensional criterion. Cathodal stimulation over Wernicke's area reduced reliance on single-dimensional solutions, while presenting informationally redundant novel labels reduced reliance on the dimension that is normally incidental in the real world. These results provide further evidence that implicit and explicit verbal labels support the process of human categorization. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. 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 < 0.05, 30 days) and Total Scores (Ƶ = 2.3, P < 0.02, 30 days), and participant ratings of the DHQ Severity (Ƶ = 1.8, P < 0.06, 5 days) and Total Scores (Ƶ = 1.9, P < 0.05, 15 days). These findings support sustained neuromodulatory effects and efficacy of tDCS to reduce 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.

  18. Nuclear magnetic resonance spectroscopic investigation of anode exhaust of direct methanol fuel cells without isotope enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Young Seok; Hwang, Reo Yun; Han, Ochee [Western Seoul Center, Korea Basic Science Institute, Seoul (Korea, Republic of)

    2016-12-15

    Fuel cells are devices that electrochemically convert the chemical energy of fuels such as natural gas, gasoline, and methanol, into electricity. Fuel cells more efficiently use energy than internal combustion engines and do not produce undesirable pollutants, such as NO{sub x} ,SO{sub x} and particulates. Fuel cells can be distinguished from one another by their electrolytes. Among the various direct alcohol fuel cells, direct methanol fuel cells (DMFCs) have been developed most. However, DMFCs have several practical problems such as methanol crossove r from an anode to a cathode and slow methanol oxidation reaction rates. Therefore, understanding the electrochemical reaction mechanisms of DMFCs may provide clues to solve these problems, and various analytical methods have been employed to examine these mechanisms. We demonstrated that {sup 1}H and {sup 13}C NMR spectroscopy can be used for analyzing anode exhausts of DMFCs operated with methanol without any isotope enrichment. However, the low sensitivity of NMR spectroscopy hindered our efforts to detect minor reaction intermediates. Therefore, sensitivity enhancement techniques such as dynamic nuclear polarization (DNP) NMR methods and/or presaturation methods to increase the dynamic range of the proton spectra by pre-saturating large water signals, are expected to be useful to detect low-concentration species.

  19. Transcranial Direct Current Stimulation of the Temporoparietal Junction and Inferior Frontal Cortex Improves Imitation-Inhibition and Perspective-Taking with no Effect on the Autism-Spectrum Quotient Score

    Directory of Open Access Journals (Sweden)

    Satoshi Nobusako

    2017-05-01

    Full Text Available Lesions to brain regions such as the temporoparietal junction (TPJ and inferior frontal cortex (IFC are thought to cause autism-spectrum disorder (ASD. Previous studies indicated that transcranial direct current stimulation (tDCS of the right TPJ improves social cognitive functions such as imitation-inhibition and perspective-taking. Although previous work shows that tDCS of the right IFC improves imitation-inhibition, its effects on perspective-taking have yet to be determined. In addition, the role of the TPJ and IFC in determining the Autism-Spectrum Quotient (AQ, which is a measure of autism spectrum traits, is still unclear. Thus, the current study performed tDCS on the right TPJ and the right IFC of healthy adults, and examined its effects on imitation-inhibition, perspective-taking and AQ scores. Based on previous studies, we hypothesized that anodal tDCS of the right IFC and right TPJ would improve imitation-inhibition, perspective-taking and the AQ score. Anodal tDCS of the right TPJ or IFC significantly decreased the interference effect in an imitation-inhibition task and the cost of perspective-taking in a perspective-taking task, in comparison to the sham stimulation control. These findings indicated that both the TPJ and the IFC play a role in imitation-inhibition and perspective-taking, i.e., control of self and other representations. However, anodal stimulation of the right TPJ and the right IFC did not alter participants’ AQ. This finding conflicts with results from previous brain imaging studies, which could be attributed to methodological differences such as variation in sex, age and ASD. Therefore, further research is necessary to determine the relationship between the TPJ and IFC, and the AQ.

  20. Strain-tolerant High Capacity Silicon Anodes via Directed Lithium Ion Transport for High Energy Density Lithium-ion Batteries

    Science.gov (United States)

    Goldman, Jason

    2012-02-01

    Energy storage is an essential component of modern technology, with applications including public infrastructure, transportation systems, and consumer electronics. Lithium-ion batteries are the preeminent form of energy storage when high energy / moderate power densities are required. Improvements to lithium-ion battery energy / power density through the adoption of silicon anodes—with approximately an order of magnitude greater gravimetric capacity than traditional carbon-based anodes--have been limited by ˜300% strains during electrochemical lithium insertion which result in short operational lifetimes. In two different systems we demonstrated improvements to silicon-based anode performance via directed lithium ion transport. The first system demonstrated a crystallographic-dependent anisotropic electrochemical lithium insertion in single-crystalline silicon anode microstructures. Exploiting this anisotropy, we highlight model silicon anode architectures that limit the maximum strain during electrochemical lithium insertion. This self-strain-limiting is a result of selecting a specific microstructure design such that during lithiation the anisotropic evolution of strain, above a given threshold, blocks further lithium intercalation. Exemplary design rules have achieved self-strain-limited charging capacities ranging from 677 mAhg-1 to 2833 mAhg-1. A second system with variably encapsulated silicon-based anodes demonstrated greater than 98% of their initial capacity after 130+ cycles. This anode also can operate stably at high energy/power densities. A lithium-ion battery with this anode was able to continuously (dis)charge in 10 minutes, corresponding to a power / energy density of ˜1460 W/kg and ˜243 Wh/kg--up to 780% greater power density and 220% higher energy density than conventional lithium-ion batteries. Anodes were also demonstrated with areal capacities of 12.7 mAh/cm^2, two orders of magnitude greater than traditional thin-film silicon anodes.[4pt

  1. Enhanced heat transfer with corrugated flow channel in anode side of direct methanol fuel cells

    International Nuclear Information System (INIS)

    Heidary, H.; Abbassi, A.; Kermani, M.J.

    2013-01-01

    Highlights: • Effect of corrugated flow channel on the heat exchange of DMFC is studied. • Corrugated boundary (except rectangular type) increase heat transfer up to 90%. • Average heat transfer in rectangular-corrugated boundary is less than straight one. • In Re > 60, wavy shape boundary has highest heat transfer. • In Re < 60, triangular shape boundary has highest heat transfer. - Abstract: In this paper, heat transfer and flow field analysis in anode side of direct methanol fuel cells (DMFCs) is numerically studied. To enhance the heat exchange between bottom cold wall and core flow, bottom wall of fluid delivery channel is considered as corrugated boundary instead of straight (flat) one. Four different shapes of corrugated boundary are recommended here: rectangular shape, trapezoidal shape, triangular shape and wavy (sinusoidal) shape. The top wall of the channel (catalyst layer boundary) is taken as hot boundary, because reaction occurs in catalyst layer and the bottom wall of the channel is considered as cold boundary due to coolant existence. The governing equations are numerically solved in the domain by the control volume approach based on the SIMPLE technique (1972). A wide spectrum of numerical studies is performed over a range of various shape boundaries, Reynolds number, triangle block number, and the triangle block amplitude. The performed parametric studies show that corrugated channel with trapezoidal, triangular and wavy shape enhances the heat exchange up to 90%. With these boundaries, cooling purpose of reacting flow in anode side of DMFCs would be better than straight one. Also, from the analogy between the heat and mass transfer problems, it is expected that the consumption of reacting species within the catalyst layer of DMFCs enhance. The present work provides helpful guidelines to the bipolar plate manufacturers of DMFCs to considerably enhance heat transfer and performance of the anode side of DMFC

  2. An air-breathing micro direct methanol fuel cell stack employing a single shared anode using silicon microfabrication technologies

    Science.gov (United States)

    Wang, Xiaohong; Zhou, Yan'an; Zhang, Qian; Zhu, Yiming; Liu, Litian

    2009-09-01

    This paper presents a silicon-based air-breathing micro direct methanol fuel cell (μDMFC) stack with a shared anode plate and two air-breathing cathode plates. Three kinds of anode plates featured by different methanol transport methods are designed and simulated. Microfabrication technologies, including double-side lithography and bulk-micromachining, are used to fabricate both anode and cathode silicon plates on the same wafer simultaneously. Three μDMFC stacks with different kinds of anodes are assembled, and characterized with a single cell together. Simulation and experimental results show that the μDMFC stack with fuel transport in a shared model has the best performance, and this stack achieves a power of 2.52 mW which is almost double that of a single cell of 1.28 mW.

  3. Transcranial Direct Current Stimulation Targeting Primary Motor Versus Dorsolateral Prefrontal Cortices: Proof-of-Concept Study Investigating Functional Connectivity of Thalamocortical Networks Specific to Sensory-Affective Information Processing.

    Science.gov (United States)

    Sankarasubramanian, Vishwanath; Cunningham, David A; Potter-Baker, Kelsey A; Beall, Erik B; Roelle, Sarah M; Varnerin, Nicole M; Machado, Andre G; Jones, Stephen E; Lowe, Mark J; Plow, Ela B

    2017-04-01

    The pain matrix is comprised of an extensive network of brain structures involved in sensory and/or affective information processing. The thalamus is a key structure constituting the pain matrix. The thalamus serves as a relay center receiving information from multiple ascending pathways and relating information to and from multiple cortical areas. However, it is unknown how thalamocortical networks specific to sensory-affective information processing are functionally integrated. Here, in a proof-of-concept study in healthy humans, we aimed to understand this connectivity using transcranial direct current stimulation (tDCS) targeting primary motor (M1) or dorsolateral prefrontal cortices (DLPFC). We compared changes in functional connectivity (FC) with DLPFC tDCS to changes in FC with M1 tDCS. FC changes were also compared to further investigate its relation with individual's baseline experience of pain. We hypothesized that resting-state FC would change based on tDCS location and would represent known thalamocortical networks. Ten right-handed individuals received a single application of anodal tDCS (1 mA, 20 min) to right M1 and DLPFC in a single-blind, sham-controlled crossover study. FC changes were studied between ventroposterolateral (VPL), the sensory nucleus of thalamus, and cortical areas involved in sensory information processing and between medial dorsal (MD), the affective nucleus, and cortical areas involved in affective information processing. Individual's perception of pain at baseline was assessed using cutaneous heat pain stimuli. We found that anodal M1 tDCS and anodal DLPFC tDCS both increased FC between VPL and sensorimotor cortices, although FC effects were greater with M1 tDCS. Similarly, anodal M1 tDCS and anodal DLPFC tDCS both increased FC between MD and motor cortices, but only DLPFC tDCS modulated FC between MD and affective cortices, like DLPFC. Our findings suggest that M1 stimulation primarily modulates FC of sensory networks

  4. Surface patterned dielectrics by direct writing of anodic oxides using scanning droplet cell microscopy

    International Nuclear Information System (INIS)

    Siket, Christian M.; Mardare, Andrei Ionut; Kaltenbrunner, Martin; Bauer, Siegfried; Hassel, Achim Walter

    2013-01-01

    Highlights: • Scanning droplet cell microscopy was applied for local gate oxide writing. • Sharp lines are obtained at the highest writing speed of 1 mm min −1 . • 13.4 kC cm −3 was found as charge per volume for aluminium oxide. • High field constant of 24 nm V −1 and dielectric constant of 12 were determined for Al 2 O 3 by CV and EIS. -- Abstract: Scanning droplet cell microscopy was used for patterning of anodic oxide lines on the surface of Al thin films by direct writing. The structural modifications of the written oxide lines as a function of the writing speed were studied by analyzing the relative error of the line widths. Sharper lines were obtained for writing speeds faster than 1 mm min −1 . An increase in sharpness was observed for higher writing speeds. A theoretical model based on the Faraday law is proposed to explain the constant anodisation current measured during the writing process and yielded a charge per volume of 13.4 kC cm −3 for Al 2 O 3 . From calculated oxide film thicknesses the high field constant was found to be 24 nm V −1 . Electrochemical impedance spectroscopy revealed an increase of the electrical permittivity up to ε = 12 with the decrease of the writing speed of the oxide line. Writing of anodic oxide lines was proven to be an important step in preparing capacitors and gate dielectrics in plastic electronics

  5. Effect of the ethanol concentration in the anode on the direct ethanol fuel cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Belchor, Pablo Martins; Loeser, Neiva; Forte, Maria Madalena de Camargo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil); Carpenter, Deyse [Fundacao Universidade Regional de Blumenau (FURB), Blumenau, SC (Brazil)], Email: rafarstv@hotmail.com

    2010-07-01

    Changes in the climate, sources and development of renewable energy are issues that have gain greater importance, and fuel cells have been investigated as an alternative source to produce energy through electrochemical reactions. Among the fuel cells types the Proton Exchange Membrane (PEMFC), fed with pure hydrogen at the anode and oxygen at the cathode, seen be the more promising ones as an electrolyte for portable, mobile and stationary applications due to its low emissions, low operating temperature, high power density and quick configuration. To avoid inconvenience of storage and transportation of pure hydrogen a PEMFC fed with alcohols has been developed, named Direct Alcohol Fuel Cells (DAFC). One way to increase the performance of DAFC is added water in the alcohol inserted into the anode, because the water keeps the membrane hydrated. In this work, the performance of a DAFC was evaluated by following the loss in the polarization curve and cell power by varying the ethanol/water ratio. The aim of this study was determine the optimal water/ethanol ratio to be feed in a DEFC prototype mounted in the lab. By the results it was possible to point that the best concentration of ethanol aqueous solution for the DEFC tested was around 1 mol.L-1. (author)

  6. Hybrid direct carbon fuel cell anode processes investigated using a 3-electrode half-cell setup

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Arenillas, A.; Menendez, J.A.

    2015-01-01

    A 3-electrode half-cell setup consisting of a yttria-stabilized zirconia (YSZ) electrolyte support was employed to investigate the chemical and electrochemical processes occurring in the vicinity of a model hybrid direct carbon fuel cell (HDCFC) anode (Ni-YSZ) in contact with a molten carbon......-alkali carbonate slurry. Electrochemical testing, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), with and without the Ni-YSZ layer highlighted the promotional effect of the Ni-YSZ anode layer, and revealed the contributions of Ni/NiO, and potentially K/K2O, redox couple(s). Treated...... anthracite and bituminous coals, as well as carbon black, were tested, revealing similar open circuit potential and activation energies in mixed 96-4vol% N2-CO2 and 50-50vol% CO-CO2 environments between 700 and 800°C. Bituminous coal showed the highest activity, likely associated to a high O/C ratio...

  7. Online and offline effects of cerebellar transcranial direct current stimulation on motor learning in healthy older adults: a randomized double-blind sham-controlled study.

    Science.gov (United States)

    Samaei, Afshin; Ehsani, Fatemeh; Zoghi, Maryam; Hafez Yosephi, Mohaddese; Jaberzadeh, Shapour

    2017-05-01

    The aim of this randomized double blinded sham-controlled study was to determine the effect of cerebellar anodal transcranial direct current stimulation (a-tDCS) on online and offline motor learning in healthy older individuals. Thirty participants were randomly assigned in experimental (n = 15) or sham tDCS (n = 15) groups. Participants in experimental group received 2 mA cerebellar a-tDCS for 20 min. However, the tDCS was turned off after 30 seconds in sham group. Response time (RT) and error rate (ER) in serial RT test were assessed before, during 35 minutes and 48 h after the intervention. Reduction of RT and ER following the intervention session was considered as short-term (35 min post intervention) and long-term offline learning (48 h post intervention), respectively. Online RT and ER reduction were similar in both groups (P > 0.05). RT was significantly reduced 48 hours post intervention in cerebellar a-tDCS group (P = 0.03). Moreover, RT was significantly increased after 35 minutes and 48 hours in sham tDCS group (P = 0.03, P = 0.007), which indicates a lack of short-term and long-term offline learning in older adults. A-tDCS on cerebellar region produced more short-term and long-term offline improvement in RT (P = 0.014, P = 0.01) compared to sham tDCS. In addition, online, short-term and long-term (48 h) offline error reduced in cerebellar a-tDCS as compared to sham-control group, although this reduction was not significant (P > 0.05). A deficit suggests that a direct comparison to a younger group was made. The findings suggested that cerebellar a-tDCS might be useful for improvement of offline motor learning in older individuals. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  8. Modulation of Brain Activity with Noninvasive Transcranial Direct Current Stimulation (tDCS: Clinical Applications and Safety Concerns

    Directory of Open Access Journals (Sweden)

    Haichao Zhao

    2017-05-01

    Full Text Available Transcranial direct current stimulation (tDCS is a widely-used tool to induce neuroplasticity and modulate cortical function by applying weak direct current over the scalp. In this review, we first introduce the underlying mechanism of action, the brief history from discovery to clinical scientific research, electrode positioning and montages, and parameter setup of tDCS. Then, we review tDCS application in clinical samples including people with drug addiction, major depression disorder, Alzheimer's disease, as well as in children. This review covers the typical characteristics and the underlying neural mechanisms of tDCS treatment in such studies. This is followed by a discussion of safety, especially when the current intensity is increased or the stimulation duration is prolonged. Given such concerns, we provide detailed suggestions regarding safety procedures for tDCS operation. Lastly, future research directions are discussed. They include foci on the development of multi-tech combination with tDCS such as with TMS and fMRI; long-term behavioral and morphological changes; possible applications in other research domains, and more animal research to deepen the understanding of the biological and physiological mechanisms of tDCS stimulation.

  9. Cathodal Transcranial Direct Current Stimulation Improves Focal Hand Dystonia in Musicians: A Two-Case Study

    Directory of Open Access Journals (Sweden)

    Sara Marceglia

    2017-09-01

    Full Text Available Focal hand dystonia (FHD in musicians is a movement disorder causing abnormal movements and irregularities in playing. Since weak electrical currents applied to the brain induce persistent excitability changes in humans, cathodal tDCS was proposed as a possible non-invasive approach for modulating cortical excitability in patients with FHD. However, the optimal targets and modalities have still to be determined. In this pilot study, we delivered cathodal (2 mA, anodal (2 mA and sham tDCS over the motor areas bilaterally for 20 min daily for five consecutive days in two musicians with FHD. After cathodal tDCS, both patients reported a sensation of general wellness and improved symptoms of FHD. In conclusion, our pilot results suggest that cathodal tDCS delivered bilaterally over motor-premotor (M-PM cortex for 5 consecutive days may be effective in improving symptoms in FHD.

  10. Novel Anodic Catalyst Support for Direct Methanol Fuel Cell: Characterizations and Single-Cell Performances.

    Science.gov (United States)

    Abdullah, N; Kamarudin, S K; Shyuan, L K

    2018-04-03

    This study introduces a novel titanium dioxide carbon nanofiber (TiO 2 -CNF) support for anodic catalyst in direct methanol fuel cell. The catalytic synthesis process involves several methods, namely the sol-gel, electrospinning, and deposition methods. The synthesized electrocatalyst is compared with other three electrocatalysts with different types of support. All of these electrocatalysts differ based on a number of physical and electrochemical characteristics. Experimental results show that the TiO 2 -CNF support gave the highest current density at 345.64 mA mg catalyst -1 , which is equivalent to 5.54-fold that of carbon support while the power density is almost double that of the commercial electrocatalyst.

  11. A tapered serpentine flow field for the anode of micro direct methanol fuel cells

    Science.gov (United States)

    Zhang, Yufeng; Zhang, Peng; Yuan, Zhenyu; He, Hong; Zhao, Youran; Liu, Xiaowei

    2011-03-01

    We develop a self-breathing micro direct methanol fuel cell (μDMFC) characterized by a new anode structure with tapered single serpentine flow fields to improve cell performance. Compared with the conventional single serpentine flow field, this new design enhances the methanol mass transport efficiency and the exhaust resultant (CO2) rate due to the increasing pressure difference between adjacent flow channels. The μDMFCs with two single serpentine flow fields are fabricated using silicon-based micro-electro-mechanical systems (MEMS) technologies and are tested at room temperature. The experimental results reveal that the new tapered single serpentine flow field exhibits a significantly higher peak power density than that of the conventional flow field, demonstrating a substantial increase of 17.9% in mass transport coefficients.

  12. Effects of transcranial direct current stimulation on pain, mood and serum endorphin level in the treatment of fibromyalgia: A double blinded, randomized clinical trial.

    Science.gov (United States)

    Khedr, Eman M; Omran, Eman A H; Ismail, Nadia M; El-Hammady, Dina H; Goma, Samar H; Kotb, Hassan; Galal, Hannan; Osman, Ayman M; Farghaly, Hannan S M; Karim, Ahmed A; Ahmed, Gehad A

    Recent studies have shown that novel neuro-modulating techniques can have pain-relieving effects in the treatment of chronic pain. The aim of this work is to evaluate the effects of transcranial direct current stimulation (tDCS) in relieving fibromyalgia pain and its relation with beta-endorphin changes. Forty eligible patients with primary fibromyalgia were randomized to receive real anodal tDCS or sham tDCS of the left motor cortex (M1) daily for 10 days. Each patient was evaluated using widespread pain index (WPI), symptom severity of fibromyalgia (SS), visual analogue scale (VAS), and determination of pain threshold as a primary outcome. Hamilton depression and anxiety scales (HAM-D and HAM-A) and estimation of serum beta-endorphin level pre and post-sessions were used as secondary outcome. All rating scales were conducted at the baseline, after the 5th, 10th session, 15 days and 1 month after the end of the sessions. Eighteen patients from each group completed the follow-up schedule with no significant difference between them regarding the duration of illness or the baseline scales. A significant TIME × GROUP interaction for each rating scale (WPI, SS, VAS, pain threshold, HAM-A, HAM-D) indicated that the effect of treatment differed in the two groups with higher improvement in the experimental scores of the patients in the real tDCS group (P = 0.001 for WPI, SS, VAS, pain threshold, and 0.002, 0.03 for HAM-A, HAM-D respectively). Negative correlations between changes in serum beta-endorphin level and the changes in different rating scales were found (P = 0.003, 0.003, 0.05, 0.002, 0002 for WPI, SS, VAS, HAM-A, and HAM-D respectively). Ten sessions of real tDCS over M1 can induce pain relief and mood improvement in patients with fibromyalgia, which were found to be related to changes in serum endorphin levels. ClinicalTrials.gov Identifier: NCT02704611. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. 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

  14. 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

  15. Repeated sessions of bilateral transcranial direct current stimulation on intractable tinnitus: a study protocol for a double-blind randomized controlled trial [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Arash Bayat

    2018-03-01

    Full Text Available Background: Transcranial Direct Current Stimulation (tDCS is reportedly a potential treatment option for chronic tinnitus. The main drawbacks of previous studies are short term follow up and focusing on the efficacy of single session tDCS. This study aims to investigate the therapeutic efficacy, adverse effects (AEs and tolerability of repeated sessions of bilateral tDCS over auditory cortex (AC on tinnitus symptoms Methods: This will be a double-blinded randomized placebo controlled parallel trial on patients (n=90 with intractable chronic tinnitus (> 2 years randomly divided into three groups of anodal, cathodal, and sham tDCS. In the sham treatment, after 30 sec the device will be turned OFF without informing the patients. The tDCS protocol consists of 10 sessions (daily  20 min session; 2 mA current for 5 consecutive days per week and 2 consecutive weeks applied through 35 cm2 electrodes. The primary outcome is tinnitus handicap inventory (THI which will be assessed pre- and post-intervention and at one month follow-up. The secondary outcomes are tinnitus loudness and distress to be assessed using a visual analogue scale (VAS pre-intervention, and immediately, one hour, one week, and one month after last stimulation. The AEs and tolerability of patients will be evaluated after each session using a customized questionnaire. Possible interactions between the disease features and treatment response will be evaluated.   Discussion: To our knowledge this is the first study to investigate the effects of repeated sessions of tDCS on chronic tinnitus symptoms with one month follow-up. In addition, the AEs, and tolerability of patients will be studied. In addition, the possible interactions between the disease specific features including the hearing loss, laterality, type of tinnitus, and treatment response will be evaluated.   Trial registration: The study has been registered as a clinical trial in Iranian Registry of Clinical Trial (IRCT

  16. Propitious Dendritic Cu2O-Pt Nanostructured Anodes for Direct Formic Acid Fuel Cells.

    Science.gov (United States)

    El-Nagar, Gumaa A; Mohammad, Ahmad M; El-Deab, Mohamed S; El-Anadouli, Bahgat E

    2017-06-14

    This study introduces a novel competent dendritic copper oxide-platinum nanocatalyst (nano-Cu 2 O-Pt) immobilized onto a glassy carbon (GC) substrate for formic acid (FA) electro-oxidation (FAO); the prime reaction in the anodic compartment of direct formic acid fuel cells (DFAFCs). Interestingly, the proposed catalyst exhibited an outstanding improvement for FAO compared to the traditional platinum nanoparticles (nano-Pt) modified GC (nano-Pt/GC) catalyst. This was evaluated from steering the reaction mechanism toward the desired direct route producing carbon dioxide (CO 2 ); consistently with mitigating the other undesired indirect pathway producing carbon monoxide (CO); the potential poison deteriorating the catalytic activity of typical Pt-based catalysts. Moreover, the developed catalyst showed a reasonable long-term catalytic stability along with a significant lowering in onset potential of direct FAO that ultimately reduces the polarization and amplifies the fuel cell's voltage. The observed catalytic enhancement was believed to originate bifunctionally; while nano-Pt represented the base for the FA adsorption, nanostructured copper oxide (nano-Cu 2 O) behaved as a catalytic mediator facilitating the charge transfer during FAO and providing the oxygen atmosphere inspiring the poison's (CO) oxidation at relatively lower potential. Surprisingly, moreover, nano-Cu 2 O induced a surface retrieval of nano-Pt active sites by capturing the poisoning CO via "a spillover mechanism" to renovate the Pt surface for the direct FAO. Finally, the catalytic tolerance of the developed catalyst toward halides' poisoning was discussed.

  17. Cognitive control therapy and transcranial direct current stimulation for depression: a randomized, double-blinded, controlled trial.

    Science.gov (United States)

    Brunoni, A R; Boggio, P S; De Raedt, R; Benseñor, I M; Lotufo, P A; Namur, V; Valiengo, L C L; Vanderhasselt, M A

    2014-06-01

    Based on findings that major depressive disorder (MDD) is associated to decreased dorsolateral prefrontal cortical (DLPFC) activity; interventions that increase DLPFC activity might theoretically present antidepressant effects. Two of them are cognitive control therapy (CCT), a neurocognitive intervention that uses computer-based working memory exercises, and transcranial direct current stimulation (tDCS), which delivers weak, electric direct currents over the scalp. We investigated whether tDCS enhanced the effects of CCT in a double-blind trial, in which participants were randomized to sham tDCS and CCT (n=17) vs. active tDCS and CCT (n=20). CCT and tDCS were applied for 10 consecutive workdays. Clinicaltrials.gov identifier: NCT01434836. Both CCT alone and combined with tDCS ameliorated depressive symptoms after the acute treatment period and at follow-up, with a response rate of approximately 25%. Older patients and those who presented better performance in the task throughout the trial (possibly indicating greater engagement and activation of the DLPFC) had greater depression improvement in the combined treatment group. Our exploratory findings should be further confirmed in prospective controlled trials. CCT and tDCS combined might be beneficial for older depressed patients, particularly for those who have cognitive resources to adequately learn and improve task performance over time. This combined therapy might be specifically relevant in this subgroup that is more prone to present cognitive decline and prefrontal cortical atrophy. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Use of transcranial direct current stimulation for the treatment of auditory hallucinations of schizophrenia – a systematic review

    Directory of Open Access Journals (Sweden)

    Pondé PH

    2017-02-01

    Full Text Available Pedro H Pondé,1 Eduardo P de Sena,2 Joan A Camprodon,3 Arão Nogueira de Araújo,2 Mário F Neto,4 Melany DiBiasi,5 Abrahão Fontes Baptista,6,7 Lidia MVR Moura,8 Camila Cosmo2,3,6,9,10 1Dynamics of Neuromusculoskeletal System Laboratory, Bahiana School of Medicine and Public Health, 2Postgraduate Program in Interactive Process of Organs and Systems, Federal University of Bahia, Salvador, Bahia, Brazil; 3Laboratory for Neuropsychiatry and Neuromodulation and Transcranial Magnetic Stimulation Clinical Service, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; 4Scientific Training Center Department, School of Medicine of Bahia, Federal University of Bahia, Salvador, Bahia, Brazil; 5Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA; 6Functional Electrostimulation Laboratory, Biomorphology Department, 7Postgraduate Program on Medicine and Human Health, School of Medicine, Federal University of Bahia, Salvador, Bahia, Brazil; 8Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; 9Center for Technological Innovation in Rehabilitation, Federal University of Bahia, 10Bahia State Health Department (SESAB, Salvador, Bahia, Brazil Introduction: Auditory hallucinations are defined as experiences of auditory perceptions in the absence of a provoking external stimulus. They are the most prevalent symptoms of schizophrenia with high capacity for chronicity and refractoriness during the course of disease. The transcranial direct current stimulation (tDCS – a safe, portable, and inexpensive neuromodulation technique – has emerged as a promising treatment for the management of auditory hallucinations. Objective: The aim of this study is to analyze the level of evidence in the literature available for the use of tDCS as a treatment for auditory hallucinations in schizophrenia. Methods: A systematic review was performed

  19. Cathodal transcranial direct current stimulation over posterior parietal cortex enhances distinct aspects of visual working memory.

    Science.gov (United States)

    Heinen, Klaartje; Sagliano, Laura; Candini, Michela; Husain, Masud; Cappelletti, Marinella; Zokaei, Nahid

    2016-07-01

    In this study, we investigated the effects of tDCS over the posterior parietal cortex (PPC) during a visual working memory (WM) task, which probes different sources of response error underlying the precision of WM recall. In two separate experiments, we demonstrated that tDCS enhanced WM precision when applied bilaterally over the PPC, independent of electrode configuration. In a third experiment, we demonstrated with unilateral electrode configuration over the right PPC, that only cathodal tDCS enhanced WM precision and only when baseline performance was low. Looking at the effects on underlying sources of error, we found that cathodal stimulation enhanced the probability of correct target response across all participants by reducing feature-misbinding. Only for low-baseline performers, cathodal stimulation also reduced variability of recall. We conclude that cathodal- but not anodal tDCS can improve WM precision by preventing feature-misbinding and hereby enhancing attentional selection. For low-baseline performers, cathodal tDCS also protects the memory trace. Furthermore, stimulation over bilateral PPC is more potent than unilateral cathodal tDCS in enhancing general WM precision. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Transcranial Direct Current Stimulation Effects on Athletes’ Cognitive Performance: An Exploratory Proof of Concept Trial

    Directory of Open Access Journals (Sweden)

    Davimar Borduchi

    2016-11-01

    Full Text Available Among the 2016 Olympic and Paralympic Games unforgettable moments, one could not overlook performances by Phelps and Bolt, which challenge old premises about the maximum extension of individual supremacism in ultracompetitive modalities and the doping scandals. Different media channels resonated these two trends, with an unseen rise on discussions about traits and practices that may set ultrahigh performance athletes apart from the more ordinary ones. Yet, some key issues remain undebated. This paper aims to add to this debate, with a proof of concept trial, which investigates whether tDCS may serve as an aid for professional athletes. Ten professional athletes of three different modalities of (judo, N=4 athletes, swimming, N=3 athletes and rhythmic gymnastics, N=3 athletes received anodal stimulation (2mA for 20 minutes on the left dorsolateral prefrontal cortex for ten consecutive weekdays. We observed a positive effect of tDCS in their cognitive performance, including a significant improvement in alternated, sustained and divided attention and in memory scores. We also observed a decrease in Beck Depression Inventory scores (4.50 points in this non-clinical population. These preliminary results suggest that tDCS sessions may translate into competitive advantages for professional athletes and recommend the deepening of the discussion on its ethical use in sports, which is ultimately tied to the wider debate around the risks and opportunities that neuromodulation brings to the table.

  1. An integrated readout system for drift chambers: the application of monolithic CMOS pixel sensors as segmented direct anode

    NARCIS (Netherlands)

    Campbell, M.; Heijne, E.H.M.; Llopart, X.; Chefdeville, M.A.; Colas, P.; Giomataris, Y.; Colijn, A.P.; Fornaini, A.; Fornaini, A.; van der Graaf, H.; Kluit, P.; Timmermans, J.; Timmermans, J.; Visschers, J.L.; Schmitz, Jurriaan

    2006-01-01

    A small TPC has been read out by means of a MediPix2 readout chip as direct anode. A Micromegas foil was placed 50 μm above the chip, and electron multiplication occurred in the gap. With a He/Isobutane 80/20 mixture, gas multiplication factors up to tens of thousands were achieved, resulting in an

  2. Combination of Transcranial Direct Current Stimulation and Neuromuscular Electrical Stimulation Improves Gait Ability in a Patient in Chronic Stage of Stroke

    OpenAIRE

    Satow, Takeshi; Kawase, Tomotaka; Kitamura, Atsushi; Kajitani, Yuki; Yamaguchi, Takuya; Tanabe, Nobuhiko; Otoi, Reiko; Komuro, Taro; Kobayashi, Akira; Nagata, Hirokazu; Mima, Tatsuya

    2016-01-01

    Background: Walking ability is important in stroke patients to maintain daily life. Nevertheless, its improvement is limited with conventional physical therapy in chronic stage. We report the case of a chronic stroke patient showing a remarkable improvement in gait function after a new neurorehabilitation protocol using transcranial direct current stimulation (tDCS) and neuromuscular electrical stimulation (NMES). Case Presentation: A 62-year-old male with left putaminal hemorrhage suffered f...

  3. Efficacy of Transcranial Direct Current Stimulation in the Treatment: Resistant Patients who Suffer from Severe Obsessive-compulsive Disorder.

    Science.gov (United States)

    Najafi, Kiomars; Fakour, Youssef; Zarrabi, Homa; Heidarzadeh, Abtin; Khalkhali, Mohammadrasoul; Yeganeh, Taiebeh; Farahi, Hasan; Rostamkhani, Marziyeh; Najafi, Tahereh; Shabafroz, Soheil; Pakdaman, Mahdiyeh

    2017-01-01

    During the past years, significant efforts have been made to explain the biological backgrounds of obsessive-compulsive disorder (OCD). Cortical-subcortical and neurotransmitter models are used for explaining the symptoms of OCD, so our hypothesis is that brain's transcranial direct current stimulation (TDCS) can regulate the brain activities of the OCD patients. Thus, based on the mentioned issues, this research seeks to investigate the efficacy of TDCS in treatment-resistant patients who suffer from severe OCD. The present study is a clinical trial research which was based on the available sampling method, 42 treatment-resistant patients who suffer from severe OCD were selected as research's samples (2015-2016). Medical intervention protocol in this study is TDCS cathode type that was done in 15 sessions for 3 consecutive weeks (each session was conducted for 30 min daily). Yale-Brown Obsessive-Compulsive Scale was used for evaluating the efficacy of TDCS method during the 1 st , 5 th , 10 th , and 15 th sessions and it was also used for checking the 1 st and 3 rd monthly follow-up phases. Variance within-group analysis (repeated measure) showed that the mean differences in the different stages of evaluation are significant (seven stages of evaluation). TDCS can be introduced as an appropriate, strong tool for regulating the brain - behavioral systems and it can also be introduced as a suitable alternative treatment for treatment-resistant patients who suffer from severe OCD.

  4. Does transcranial direct current stimulation to prefrontal cortex affect mood and emotional memory retrieval in healthy individuals?

    Science.gov (United States)

    Morgan, Helen M; Davis, Nick J; Bracewell, R Martyn

    2014-01-01

    Studies using transcranial direct current stimulation (tDCS) of prefrontal cortex to improve symptoms of depression have had mixed results. We examined whether using tDCS to change the balance of activity between left and right dorsolateral prefrontal cortex (DLPFC) can alter mood and memory retrieval of emotional material in healthy volunteers. Participants memorised emotional images, then tDCS was applied bilaterally to DLPFC while they performed a stimulus-response compatibility task. Participants were then presented with a set of images for memory retrieval. Questionnaires to examine mood and motivational state were administered at the beginning and end of each session. Exploratory data analyses showed that the polarity of tDCS to DLPFC influenced performance on a stimulus-response compatibility task and this effect was dependent on participants' prior motivational state. However, tDCS polarity had no effect on the speed or accuracy of memory retrieval of emotional images and did not influence positive or negative affect. These findings suggest that the balance of activity between left and right DLPFC does not play a critical role in the mood state of healthy individuals. We suggest that the efficacy of prefrontal tDCS depends on the initial activation state of neurons and future work should take this into account.

  5. Moving Forward By Stimulating the Brain: Transcranial Direct Current Stimulation in Post-Stroke Hemiparesis: A Mini Review

    Directory of Open Access Journals (Sweden)

    Heather T. Peters

    2016-08-01

    Full Text Available Stroke remains a leading cause of disability worldwide, with a majority of survivors experiencing long term decrements in motor function that severely undermine quality of life. While many treatment approaches and adjunctive strategies exist to remediate motor impairment, many are only efficacious or feasible for survivors with active hand and wrist function, a population who constitute only a minority of stroke survivors. Transcranial direct current stimulation (tDCS, a type of noninvasive brain stimulation, has been increasingly utilized to increase motor function following stroke as it is able to be used with stroke survivors of varying impairment levels, is portable, is relatively inexpensive and has few side effects and contraindications. Accordingly, in recent years the number of studies investigating its efficacy when utilized as an adjunct to motor rehabilitation regimens has drastically increased. While many of these trials have reported positive and promising efficacy, methodologies vary greatly between studies, including differences in stimulation parameters, outcome measures and the nature of physical practice. As such, an urgent need remains, centering on the need to investigate these methodological differences and synthesize the most current evidence surrounding the application of tDCS for post-stroke motor rehabilitation. Accordingly, the purpose of this paper is to provide a detailed overview of the most recent tDCS literature (published 2014-2015, while highlighting these variations in methodological approach, as well to elucidate the mechanisms associated with tDCS and post-stroke motor re-learning and neuroplasticity.

  6. 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.

  7. Crossover design in transcranial direct current stimulation studies on motor learning: potential pitfalls and difficulties in interpretation of findings.

    Science.gov (United States)

    Biabani, Mana; Farrell, Michael; Zoghi, Maryam; Egan, Gary; Jaberzadeh, Shapour

    2017-12-12

    Crossover designs are used by a high proportion of studies investigating the effects of transcranial direct current stimulation (tDCS) on motor learning. These designs necessitate attention to aspects of data collection and analysis to take account of design-related confounds including order, carryover, and period effects. In this systematic review, we appraised the method sections of crossover-designed tDCS studies of motor learning and discussed the strategies adopted to address these factors. A systematic search of 10 databases was performed and 19 research papers, including 21 experimental studies, were identified. Potential risks of bias were addressed in all of the studies, however, not in a rigorous and structured manner. In the data collection phase, unclear methods of randomization, various lengths of washout period, and inconsistency in the counteracting period effect can be observed. In the analytical procedures, the stratification by sequence group was often ignored, and data were treated as if it belongs to a simple repeated-measures design. An inappropriate use of crossover design can seriously affect the findings and therefore the conclusions drawn from tDCS studies on motor learning. The results indicate a pressing need for the development of detailed guidelines for this type of studies to benefit from the advantages of a crossover design.

  8. Differential sensory cortical involvement in auditory and visual sensorimotor temporal recalibration: Evidence from transcranial direct current stimulation (tDCS).

    Science.gov (United States)

    Aytemür, Ali; Almeida, Nathalia; Lee, Kwang-Hyuk

    2017-02-01

    Adaptation to delayed sensory feedback following an action produces a subjective time compression between the action and the feedback (temporal recalibration effect, TRE). TRE is important for sensory delay compensation to maintain a relationship between causally related events. It is unclear whether TRE is a sensory modality-specific phenomenon. In 3 experiments employing a sensorimotor synchronization task, we investigated this question using cathodal transcranial direct-current stimulation (tDCS). We found that cathodal tDCS over the visual cortex, and to a lesser extent over the auditory cortex, produced decreased visual TRE. However, both auditory and visual cortex tDCS did not produce any measurable effects on auditory TRE. Our study revealed different nature of TRE in auditory and visual domains. Visual-motor TRE, which is more variable than auditory TRE, is a sensory modality-specific phenomenon, modulated by the auditory cortex. The robustness of auditory-motor TRE, unaffected by tDCS, suggests the dominance of the auditory system in temporal processing, by providing a frame of reference in the realignment of sensorimotor timing signals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Impedance of vapor feed direct methanol fuel cells--polarization dependence of elementary processes at the anode

    International Nuclear Information System (INIS)

    Fukunaga, Hiroshi; Ishida, Tomohiro; Teranishi, Nozomu; Arai, Chikao; Yamada, Koichi

    2004-01-01

    Membrane electrode assemblies of direct methanol fuel cells (DMFCs) with different catalyst and ionomer loading were prepared. Anode performance and impedance spectra were measured to clarify the characteristics of vapor feed DMFCs (VF-DMFCs). The impedance spectra were deconvolved into three semi-circles with different time constants, each showing a different dependence on the anodic polarization. The middle-frequency range arc decreased as the anodic polarization increased, indicating that this process represents the oxidation reaction of methanol. The high-frequency range arc showed little dependence on the anodic polarization, but increased with the thickness of the electrode, indicating that this process might be related to proton conduction through the electrode. The low-frequency range arc was observed only when the methanol concentration was low, in contrast to liquid feed DMFCs (LF-DMFCs), for which the removal of the product gas presents a large resistance. A simpler design can therefore be used for a VF-DMFC, giving it an advantage over an LF-DMFC. A decreasing ionomer to catalyst ratio (I/C) caused the interfacial conductivity (σ E ) to increase, but it intensively decreased when I/C was below 0.25. Thus, the connection of the catalysts is important for the anode's performance

  10. Design, fabrication and testing of an air-breathing micro direct methanol fuel cell with compound anode flow field

    Science.gov (United States)

    Wang, Luwen; Zhang, Yufeng; Zhao, Youran; An, Zijiang; Zhou, Zhiping; Liu, Xiaowei

    2011-10-01

    An air-breathing micro direct methanol fuel cell (μDMFC) with a compound anode flow field structure (composed of the parallel flow field and the perforated flow field) is designed, fabricated and tested. To better analyze the effect of the compound anode flow field on the mass transfer of methanol, the compound flow field with different open ratios (ratio of exposure area to total area) and thicknesses of current collectors is modeled and simulated. Micro process technologies are employed to fabricate the end plates and current collectors. The performances of the μDMFC with a compound anode flow field are measured under various operating parameters. Both the modeled and the experimental results show that, comparing the conventional parallel flow field, the compound one can enhance the mass transfer resistance of methanol from the flow field to the anode diffusion layer. The results also indicate that the μDMFC with an anode open ratio of 40% and a thickness of 300 µm has the optimal performance under the 7 M methanol which is three to four times higher than conventional flow fields. Finally, a 2 h stability test of the μDMFC is performed with a methanol concentration of 7 M and a flow velocity of 0.1 ml min-1. The results indicate that the μDMFC can work steadily with high methanol concentration.

  11. Ni modified ceramic anodes for direct-methane solid oxide fuel cells

    Science.gov (United States)

    Xiao, Guoliang; Chen, Fanglin

    2016-01-19

    In accordance with certain embodiments of the present disclosure, a method for fabricating a solid oxide fuel cell is described. The method includes synthesizing a composition having a perovskite present therein. The method further includes applying the composition on an electrolyte support to form an anode and applying Ni to the composition on the anode.

  12. PtRu/Ti anodes with varying Pt ratio: Ru ratio prepared by electrodeposition for the direct methanol fuel cell.

    Science.gov (United States)

    Shao, Zhi-Gang; Zhu, Fuyun; Lin, Wen-Feng; Christensen, Paul A; Zhang, Huamin

    2006-06-21

    PtRu/Ti anodes with varying Pt ratio Ru ratio were prepared by electrodeposition of a thin PtRu catalyst layer onto Ti mesh for a direct methanol fuel cell (DMFC). The morphology and structure of the catalyst layers were analyzed by SEM, EDX and XRD. The catalyst coating layer shows an alloy character. The relative activities of the PtRu/Ti electrodes were assessed and compared in half cell and single DMFC experiments. The results show that these electrodes are very active for the methanol oxidation and that the optimum Ru surface coverage was ca. 9 at.% for DMFC operating at 20 degrees C and 11 at.% at 60 degrees C. The PtRu/Ti anode shows a performance comparable to that of the conventional carbon-based anode in a DMFC operating with 0.25 M or 0.5 M methanol solution and atmosphere oxygen gas at 90 degrees C.

  13. A pragmatic analysis of the regulation of consumer transcranial direct current stimulation (TDCS) devices in the United States.

    Science.gov (United States)

    Wexler, Anna

    2015-11-01

    Several recent articles have called for the regulation of consumer transcranial direct current stimulation (tDCS) devices, which provide low levels of electrical current to the brain. However, most of the discussion to-date has focused on ethical or normative considerations; there has been a notable absence of scholarship regarding the actual legal framework in the United States. This article aims to fill that gap by providing a pragmatic analysis of the consumer tDCS market and relevant laws and regulations. In the five main sections of this manuscript, I take into account (a) the history of the do-it-yourself tDCS movement and the subsequent emergence of direct-to-consumer devices; (b) the statutory language of the Federal Food, Drug and Cosmetic Act and how the definition of a medical device-which focuses on the intended use of the device rather than its mechanism of action-is of paramount importance for discussions of consumer tDCS device regulation; (c) how both the Food and Drug Administration (FDA) and courts have understood the FDA's jurisdiction over medical devices in cases where the meaning of 'intended use' has been challenged; (d) an analysis of consumer tDCS regulatory enforcement action to-date; and (e) the multiple US authorities, other than the FDA, that can regulate consumer brain stimulation devices. Taken together, this paper demonstrates that rather than a 'regulatory gap,' there are multiple, distinct pathways by which consumer tDCS can be regulated in the United States.

  14. A pragmatic analysis of the regulation of consumer transcranial direct current stimulation (TDCS) devices in the United States

    Science.gov (United States)

    2015-01-01

    Several recent articles have called for the regulation of consumer transcranial direct current stimulation (tDCS) devices, which provide low levels of electrical current to the brain. However, most of the discussion to-date has focused on ethical or normative considerations; there has been a notable absence of scholarship regarding the actual legal framework in the United States. This article aims to fill that gap by providing a pragmatic analysis of the consumer tDCS market and relevant laws and regulations. In the five main sections of this manuscript, I take into account (a) the history of the do-it-yourself tDCS movement and the subsequent emergence of direct-to-consumer devices; (b) the statutory language of the Federal Food, Drug and Cosmetic Act and how the definition of a medical device—which focuses on the intended use of the device rather than its mechanism of action—is of paramount importance for discussions of consumer tDCS device regulation; (c) how both the Food and Drug Administration (FDA) and courts have understood the FDA's jurisdiction over medical devices in cases where the meaning of ‘intended use’ has been challenged; (d) an analysis of consumer tDCS regulatory enforcement action to-date; and (e) the multiple US authorities, other than the FDA, that can regulate consumer brain stimulation devices. Taken together, this paper demonstrates that rather than a ‘regulatory gap,’ there are multiple, distinct pathways by which consumer tDCS can be regulated in the United States. PMID:27774217

  15. Anodic dissolution polarography used for the direct determination of metals in uranium

    International Nuclear Information System (INIS)

    Bueno, L.A.O.; Abrao, A.

    1976-01-01

    An electrochemical method of analysis, consisting of pre-concentration and determination of the elements Cd, Pb, Tl, Bi and Cu, present as impurities in uranium salts has been developed. The anodic stripping polarography has been employed using a dropping mercury electrode. The interference of uranium itself in the determination of these elements was eliminated by changing its reduction potential to - 1,0V (with respect to the Ag/AgCl electrode), thus making possible the analysis of the elements that are reduced at more positive potentials. This was achieved by the addition of sufficient amount of K 2 CO 3 to the uranyl chloride solution (in the 4:1 carbonate to uranyl ratio) so as to form the uranyl tricarbonate ([UO 2 (CO 3 ) 3 ] 4- ) complex anion. The supporting electrolyte was the uranyl complex in K 2 CO 3 0,1M. The final concentration of uranium ranged from 2 to 5 g/l. The detection limits for the studied elements varied from 0,08 to 1,27 ppm (μg of the element/gU). This technique has proved to be very convenient since provides sensitivity and precision. The method makes possible the determination of mentioned elements directly in uranium solutions, avoiding any previous chemical separations [pt

  16. Occipital Nerve Field Transcranial Direct Current Stimulation Normalizes Imbalance Between Pain Detecting and Pain Inhibitory Pathways in Fibromyalgia.

    Science.gov (United States)

    De Ridder, Dirk; Vanneste, Sven

    2017-04-01

    Occipital nerve field (OCF) stimulation with subcutaneously implanted electrodes is used to treat headaches, more generalized pain, and even failed back surgery syndrome via unknown mechanisms. Transcranial direct current stimulation (tDCS) can predict the efficacy of implanted electrodes. The purpose of this study is to unravel the neural mechanisms involved in global pain suppression, mediated by occipital nerve field stimulation, within the realm of fibromyalgia. Nineteen patients with fibromyalgia underwent a placebo-controlled OCF tDCS. Electroencephalograms were recorded at baseline after active and sham stimulation. In comparison with healthy controls, patients with fibromyalgia demonstrate increased dorsal anterior cingulate cortex, increased premotor/dorsolateral prefrontal cortex activity, and an imbalance between pain-detecting dorsal anterior cingulate cortex and pain-suppressing pregenual anterior cingulate cortex activity, which is normalized after active tDCS but not sham stimulation associated with increased pregenual anterior cingulate cortex activation. The imbalance improvement between the pregenual anterior cingulate cortex and the dorsal anterior cingulate cortex is related to clinical changes. An imbalance assumes these areas communicate and, indeed, abnormal functional connectivity between the dorsal anterior cingulate cortex and pregenual anterior cingulate cortex is noted to be caused by a dysfunctional effective connectivity from the pregenual anterior cingulate cortex to the dorsal anterior cingulate cortex, which improves and normalizes after real tDCS but not sham tDCS. In conclusion, OCF tDCS exerts its effect via activation of the descending pain inhibitory pathway and de-activation of the salience network, both of which are abnormal in fibromyalgia.

  17. Combined mnemonic strategy training and high-definition transcranial direct current stimulation for memory deficits in mild cognitive impairment.

    Science.gov (United States)

    Hampstead, Benjamin M; Sathian, Krishnankutty; Bikson, Marom; Stringer, Anthony Y

    2017-09-01

    Memory deficits characterize Alzheimer's dementia and the clinical precursor stage known as mild cognitive impairment. Nonpharmacologic interventions hold promise for enhancing functioning in these patients, potentially delaying functional impairment that denotes transition to dementia. Previous findings revealed that mnemonic strategy training (MST) enhances long-term retention of trained stimuli and is accompanied by increased blood oxygen level-dependent signal in the lateral frontal and parietal cortices as well as in the hippocampus. The present study was designed to enhance MST generalization, and the range of patients who benefit, via concurrent delivery of transcranial direct current stimulation (tDCS). This protocol describes a prospective, randomized controlled, four-arm, double-blind study targeting memory deficits in those with mild cognitive impairment. Once randomized, participants complete five consecutive daily sessions in which they receive either active or sham high definition tDCS over the left lateral prefrontal cortex, a region known to be important for successful memory encoding and that has been engaged by MST. High definition tDCS (active or sham) will be combined with either MST or autobiographical memory recall (comparable to reminiscence therapy). Participants undergo memory testing using ecologically relevant measures and functional magnetic resonance imaging before and after these treatment sessions as well as at a 3-month follow-up. Primary outcome measures include face-name and object-location association tasks. Secondary outcome measures include self-report of memory abilities as well as a spatial navigation task (near transfer) and prose memory (medication instructions; far transfer). Changes in functional magnetic resonance imaging will be evaluated during both task performance and the resting-state using activation and connectivity analyses. The results will provide important information about the efficacy of cognitive and

  18. USING TRANSCRANIAL DIRECT CURRENT STIMULATION (TDCS TO TREAT DEPRESSION IN HIV-INFECTED PERSONS: THE OUTCOMES OF A FEASIBILITY STUDY

    Directory of Open Access Journals (Sweden)

    Helena eKnotkova

    2012-06-01

    Full Text Available Transcranial direct current stimulation (tDCS is a novel non-invasive neuromodulatory method that influences neuronal firing rates and activity on dopaminergic and serotoninergic circuits. TDCS has been shown to relieve Major Depressive Disorder (MDD in the general population, suggesting its potential for other vulnerable -populations with high MDD prevalence. Aims: This study evaluated l feasibility, safety, acceptability and clinical outcomes of a two-week tDCS antidepressant treatment in HIV-MDD co-diagnosed patients, and the feasibility of collecting serum and saliva for analysis of immunity-biomarkers.. Methods: Ten enrolled patients underwent baseline evaluation and started the tDCS treatment (Mon-Fri for two weeks delivered with Phoressor II 850 PM for 20 min at 2 mA at each visit, using 2 electrodes (36cm2 placed over F3 position of EEG 10-20 system and the contralateral supraorbital region. Outcome-measures were collected at baseline, after the last tDCS and two weeks later. A quantitative microarray (Ray Bio Tech Inc for TH1/TH2 cytokines was used for saliva and blood analysis. Results: Analyzable outcome-data were obtained from 8 subjects. Depression scores significantly decreased (p<.0005 after the treatment. No serious adverse events occurred. Several transient minor AEs and occasional changes of blood pressure and heart rate were noted. Mini-mental status scores remained unchanged or increased after the treatment. All subjects were highly satisfied with the protocol and treatment results and described the desire to find new treatments for HIV-MDD as motivating participation. Conclusions: F indings support feasibility and clinical potential of tDCS for HIV-MDD patients, and justify larger-sample, sham-controlled trials.

  19. Remotely-Supervised Transcranial Direct Current Stimulation (tDCS for Clinical Trials: Guidelines for Technology and Protocols

    Directory of Open Access Journals (Sweden)

    Leigh E Charvet

    2015-03-01

    Full Text Available The effect of transcranial direct current stimulation (tDCS is cumulative. Treatment protocols typically require multiple consecutive sessions spanning weeks or months. However, traveling to clinic for a tDCS session can present an obstacle to subjects and their caregivers. With modified devices and headgear, tDCS treatment can be administered remotely under clinical supervision, potentially enhancing recruitment, throughput, and convenience. Here we propose standards and protocols for clinical trials utilizing remotely-supervised tDCS with the goal of providing safe, reproducible and well-tolerated stimulation therapy outside of the clinic. The recommendations include: 1 training of staff in tDCS treatment and supervision, 2 assessment of the user’s capability to participate in tDCS remotely, 3 ongoing training procedures and materials including assessments of the user and/or caregiver, 4 simple and fail-safe electrode preparation techniques and tDCS headgear, 5 strict dose control for each session, 6 ongoing monitoring to quantify compliance (device preparation, electrode saturation/placement, stimulation protocol, with corresponding corrective steps as required, 7 monitoring for treatment-emergent adverse effects, 8 guidelines for discontinuation of a session and/or study participation including emergency failsafe procedures tailored to the treatment population’s level of need. These guidelines are intended to provide a minimal level of methodological rigor for clinical trials seeking to apply tDCS outside a specialized treatment center. We outline indication-specific applications (Attention Deficit Hyperactivity Disorder, Depression, Multiple Sclerosis, Palliative Care following these recommendations that support a standardized framework for evaluating the tolerability and reproducibility of remote-supervised tDCS that, once established, will allow for translation of tDCS clinical trials to a greater size and range of patient populations.

  20. Transcranial direct current stimulation improves short-term memory in an animal model of attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Leffa, Douglas Teixeira; de Souza, Andressa; Scarabelot, Vanessa Leal; Medeiros, Liciane Fernandes; de Oliveira, Carla; Grevet, Eugenio Horacio; Caumo, Wolnei; de Souza, Diogo Onofre; Rohde, Luis Augusto Paim; Torres, Iraci L S

    2016-02-01

    Attention deficit hyperactivity disorder (ADHD) is characterized by impairing levels of hyperactivity, impulsivity and inattention. However, different meta-analyses have reported disruptions in short and long-term memory in ADHD patients. Previous studies indicate that mnemonic dysfunctions might be the result of deficits in attentional circuits, probably due to ineffective dopaminergic modulation of hippocampal synaptic plasticity. In this study we aimed to evaluate the potential therapeutic effects of a neuromodulatory technique, transcranial direct current stimulation (tDCS), in short-term memory (STM) deficits presented by the spontaneous hypertensive rats (SHR), the most widely used animal model of ADHD. Adult male SHR and Wistar Kyoto rats (WKY) were subjected to a constant electrical current of 0.5 mA intensity applied on the frontal cortex for 20 min/day during 8 days. STM was evaluated with an object recognition test conducted in an open field. Exploration time and locomotion were recorded, and brain regions were dissected to determine dopamine and BDNF levels. SHR spent less time exploring the new object when compared to WKY, and tDCS improved object recognition deficits in SHR without affecting WKY performance. Locomotor activity was higher in SHR and it was not affected by tDCS. After stimulation, dopamine levels were increased in the hippocampus and striatum of both strains, while BDNF levels were increased only in the striatum of WKY. These findings suggest that tDCS on the frontal cortex might be able to improve STM deficits present in SHR, which is potentially related to dopaminergic neurotransmission in the hippocampus and striatum of those animals. Copyright © 2016. Published by Elsevier B.V.

  1. COMETS2: An advanced MATLAB toolbox for the numerical analysis of electric fields generated by transcranial direct current stimulation.

    Science.gov (United States)

    Lee, Chany; Jung, Young-Jin; Lee, Sang Jun; Im, Chang-Hwan

    2017-02-01

    Since there is no way to measure electric current generated by transcranial direct current stimulation (tDCS) inside the human head through in vivo experiments, numerical analysis based on the finite element method has been widely used to estimate the electric field inside the head. In 2013, we released a MATLAB toolbox named COMETS, which has been used by a number of groups and has helped researchers to gain insight into the electric field distribution during stimulation. The aim of this study was to develop an advanced MATLAB toolbox, named COMETS2, for the numerical analysis of the electric field generated by tDCS. COMETS2 can generate any sizes of rectangular pad electrodes on any positions on the scalp surface. To reduce the large computational burden when repeatedly testing multiple electrode locations and sizes, a new technique to decompose the global stiffness matrix was proposed. As examples of potential applications, we observed the effects of sizes and displacements of electrodes on the results of electric field analysis. The proposed mesh decomposition method significantly enhanced the overall computational efficiency. We implemented an automatic electrode modeler for the first time, and proposed a new technique to enhance the computational efficiency. In this paper, an efficient toolbox for tDCS analysis is introduced (freely available at http://www.cometstool.com). It is expected that COMETS2 will be a useful toolbox for researchers who want to benefit from the numerical analysis of electric fields generated by tDCS. Copyright © 2016. Published by Elsevier B.V.

  2. Clinical pilot study of transcranial direct current stimulation combined with Cognitive Emotional Training for medication resistant depression.

    Science.gov (United States)

    Martin, D M; Teng, J Z; Lo, T Y; Alonzo, A; Goh, T; Iacoviello, B M; Hoch, M M; Loo, C K

    2018-05-01

    While the clinical results from transcranial direct current stimulation (tDCS) for the treatment of depression have been promising, antidepressant effects in patients with medication resistance have been suboptimal. There is therefore a need to further optimise tDCS for medication resistant patients. In this clinical pilot study we examined the feasibility, safety, and clinical efficacy of combining tDCS with a psychological intervention which targets dysfunctional circuitry related to emotion regulation in depression, Cognitive Emotional Training (CET). tDCS was administered during CET three times a week for a total of 18 sessions over 6 weeks. Mood, cognition and emotion processing outcomes were examined at baseline and after 3 and 6 weeks of treatment. Twenty patients with medication resistant depression participated, of whom 17 were study completers. tDCS combined with CET was found to be feasible, safe, and associated with significant antidepressant efficacy at 6 weeks, with 41% of study completers showing treatment response (≥ 50% improvement in depression score). There were no significant cognitive enhancing effects with the exception of improved emotion recognition. Responders demonstrated superior recognition for the emotions fear and surprise at pre-treatment compared to non-responders, suggesting that better pre-treatment emotion recognition may be associated with antidepressant efficacy. This was an open label study. tDCS combined with CET has potential as a novel method for optimising the antidepressant efficacy of tDCS in medication resistant patients. Future controlled studies are required to determine whether tDCS combined with CET has greater antidepressant efficacy compared to either intervention alone. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    DEFF Research Database (Denmark)

    Jung, Nikolai H; Delvendahl, Igor; Pechmann, Astrid

    2012-01-01

    Transcranial magnetic stimulation (TMS) commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor...

  4. Combined effect of prefrontal transcranial direct current stimulation and a working memory task on heart rate variability.

    Directory of Open Access Journals (Sweden)

    Stevan Nikolin

    Full Text Available Prefrontal cortex activity has been associated with changes to heart rate variability (HRV via mediation of the cortico-subcortical pathways that regulate the parasympathetic and sympathetic branches of the autonomic nervous system. Changes in HRV due to altered prefrontal cortex functioning can be predicted using the neurovisceral integration model, which suggests that prefrontal hyperactivity increases parasympathetic tone and decreases contributions from the sympathetic nervous system. Working memory (WM tasks and transcranial direct current stimulation (tDCS have been used independently to modulate brain activity demonstrating changes to HRV in agreement with the model. We investigated the combined effects of prefrontal tDCS and a WM task on HRV. Bifrontal tDCS was administered for 15 minutes at 2mA to 20 participants in a sham controlled, single-blind study using parallel groups. A WM task was completed by participants at three time points; pre-, during-, and post-tDCS, with resting state data collected at similar times. Frequency-domain HRV was computed for high frequency (HF; 0.15-0.4Hz and low frequency (LF; 0.04-0.15Hz power reflecting parasympathetic and sympathetic branch activity, respectively. Response time on the WM task, but not accuracy, improved from baseline to during-tDCS and post-tDCS with sham, but not active, stimulation. HF-HRV was significantly increased in the active tDCS group compared to sham, lasting beyond cessation of stimulation. Additionally, HF-HRV showed a task-related reduction in power during performance on the WM task. Changes in LF-HRV were moderately inversely correlated (r > 0.4 with changes in WM accuracy during and following tDCS compared to baseline levels. Stimulation of the prefrontal cortex resulted in changes to the parasympathetic branch of the nervous system in agreement with a linearly additive interpretation of effects. Sympathetic activity was not directly altered by tDCS, but was correlated

  5. Early adopters of the magical thinking cap: a study on do-it-yourself (DIY) transcranial direct current stimulation (tDCS) user community

    OpenAIRE

    Jwa, Anita

    2015-01-01

    Among currently available technologies, transcranial direct current stimulation (tDCS) is one of the most promising neuroenhancements because it is relatively effective, safe, and affordable. Recently, lay people have begun to build?or purchase?the tDCS device to use it at home for treatment or as a cognitive enhancer. The tDCS device is currently not covered by the existing regulatory framework, but there are still significant potential risks of misusing this device, and its long-term effect...

  6. Evaluation of the effectiveness of transcranial direct current stimulation (tDCS) and psychosensory stimulation through DOCS scale in a minimally conscious subject.

    Science.gov (United States)

    Dimitri, Danilo; De Filippis, Daniela; Galetto, Valentina; Zettin, Marina

    2017-04-01

    The aim of our study was to assess the effectiveness of transcranial direct current stimulation (tDCS) on alertness improvement in a patient in a minimally conscious state (MCS) by means of disorders of consciousness scale combined with psycho-sensory stimulation. The effects of tDCS on muscle hypertonia through the Ashworth scale were also examined. tDCS was performed through a two-channel intra-cephalic stimulator. After stimulation, the patient followed a psychosensory stimulation training. Results pointed out an increase in DOCunit score, as well as an increase in alertness maintenance and an improvement in muscle hypertonia, although a MCS state persisted.

  7. Cathodal transcranial direct current stimulation can stabilize perception of movement: Evidence from the two-thirds power law illusion.

    Science.gov (United States)

    Scocchia, Lisa; Bolognini, Nadia; Convento, Silvia; Stucchi, Natale

    2015-11-16

    Human movements conform to specific kinematic laws of motion. One of such laws, the "two-thirds power law", describes the systematic co-variation between curvature and velocity of body movements. Noticeably, the same law also influences the perception of moving stimuli: the velocity of a dot moving along a curvilinear trajectory is perceived as uniform when the dot kinematics complies with the two-thirds power law. Instead, if the dot moves at constant speed, its velocity is perceived as highly non-uniform. This dynamic visual illusion points to a strong coupling between action and perception; however, how this coupling is implemented in the brain remains elusive. In this study, we tested whether the premotor cortex (PM) and the primary visual cortex (V1) play a role in the illusion by means of transcranial Direct Current Stimulation (tDCS). All participants underwent three tDCS sessions during which they received active or sham cathodal tDCS (1.5mA) over PM or V1 of the left hemisphere. During tDCS, participants were required to adjust the velocity of a dot moving along an elliptical trajectory until it looked uniform across the whole trajectory. Results show that occipital tDCS decreases the illusion variability both within and across participants, as compared to sham tDCS. This means that V1 stimulation increases individual sensitivity to the illusory motion and also increases coherence across different observers. Conversely, the illusion seems resistant to tDCS in terms of its magnitude, with cathodal stimulation of V1 or PM not affecting the amount of the illusory effect. Our results provide evidence for strong visuo-motor coupling in visual perception: the velocity of a dot moving along an elliptical trajectory is perceived as uniform only when its kinematics closely complies to the same law of motion that constrains human movement production. Occipital stimulation by cathodal tDCS can stabilize such illusory percept. Copyright © 2015 Elsevier Ireland Ltd

  8. The impact of anode design on fuel crossover of direct ethanol fuel cell

    Indian Academy of Sciences (India)

    Fuel cell; PEM; ethanol; anode design; fuel crossover; characterization. 1. Introduction. The upsurge in the use of internal combustion (IC) engine vehicles is causing considerable pollution problems in our urban conurbations [1] and as a consequence finding a clean and reliable power system for the forthcoming generation ...

  9. Pd and polyaniline nanocomposite on carbon fiber paper as an efficient direct formic acid fuel cell anode

    Science.gov (United States)

    Pandey, Rakesh K.

    2018-03-01

    Direct formic acid fuel cells are advantageous as portable power generating devices. In the present work, an anode catalyst for direct formic acid fuel cell (DFAFC) is presented which has good catalytic activity for formic acid oxidation. The catalyst is composed of Pd and conducting polymer polyaniline (Pd-PANI) nanocomposite. The catalyst was prepared by using a single step galvanostatic electrochemical deposition method. The Pd-PANI catalyst was electrodeposited at different time durations and a comparison of the catalytic activity at each deposition time was carried out and optimized.

  10. Activation of the prefrontal cortex by unilateral transcranial direct current stimulation leads to an asymmetrical effect on risk preference in frames of gain and loss.

    Science.gov (United States)

    Ye, Hang; Huang, Daqiang; Wang, Siqi; Zheng, Haoli; Luo, Jun; Chen, Shu

    2016-10-01

    Previous brain imaging and brain stimulation studies have suggested that the dorsolateral prefrontal cortex may be critical in regulating risk-taking behavior, although its specific causal effect on people's risk preference remains controversial. This paper studied the independent modulation of the activity of the right and left dorsolateral prefrontal cortex using various configurations of transcranial direct current stimulation. We designed a risk-measurement table and adopted a within-subject design to compare the same participant's risk preference before and after unilateral stimulation when presented with different frames of gain and loss. The results confirmed a hemispheric asymmetry and indicated that the right dorsolateral prefrontal cortex has an asymmetric effect on risk preference regarding frames of gain and loss. Enhancing the activity of the right dorsolateral prefrontal cortex significantly decreased the participants' degree of risk aversion in the gain frame, whereas it increased the participants' degree of risk aversion in the loss frame. Our findings provide important information regarding the impact of transcranial direct current stimulation on the risk preference of healthy participants. The effects observed in our experiment compared with those of previous studies provide further evidence of the effects of hemispheric and frame-dependent asymmetry. These findings may be helpful in understanding the neural basis of risk preference in humans, especially when faced with decisions involving possible gain or loss relative to the status quo. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. 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.

  12. Effects of Transcranial Direct Current Stimulation Block Remifentanil-Induced Hyperalgesia: A Randomized, Double-Blind Clinical Trial

    Directory of Open Access Journals (Sweden)

    Gilberto Braulio

    2018-02-01

    Full Text Available Background: Remifentanil-induced hyperalgesia (r-IH involves an imbalance in the inhibitory and excitatory systems. As the transcranial Direct Current Stimulation (tDCS modulates the thalamocortical synapses in a top-down manner, we hypothesized that the active (a-t-DCS would be more effective than sham(s-tDCS to prevent r-IH. We used an experimental paradigm to induce temporal summation of pain utilizing a repetitive cold test (rCOLDT assessed by the Numerical Pain Score (NPS 0-10 and we evaluated the function of the descending pain modulatory system (DPMS by the change on the NPS (0–10 during the conditioned pain modulation (CPM-task (primary outcomes. We tested whether a-tDCS would be more effective than s-tDCS to improve pain perception assessed by the heat pain threshold (HPT and the reaction time during the ice-water pain test (IPT (secondary outcomes.Methods: This double-blinded, factorial randomized trial included 48 healthy males, ages ranging 19–40 years. They were randomized into four equal groups: a-tDCS/saline, s-tDCS/saline, a-tDCS/remifentanil and s-tDCS/remifentanil. tDCS was applied over the primary motor cortex, during 20 min at 2 mA, which was introduced 10 min after starting remifentanil infusion at 0.06 μg⋅kg-1⋅min-1 or saline.Results: An ANCOVA mixed model revealed that during the rCOLDT, there was a significant main effect on the NPS scores (F = 3.81; P = 0.01. The s-tDCS/remifentanil group presented larger pain scores during rCOLDT, [mean (SD 5.49 (1.04] and a-tDCS/remifentanil group had relative lower pain scores [4.15 (1.62]; showing its blocking effect on r-IH. a-tDCS/saline and s-tDCS/saline groups showed lowest pain scores during rCOLDT, [3.11 (1.2] and [3.15 (1.62], respectively. The effect of sedation induced by remifentanil during the rCOLDT was not significant (F = 0.76; P = 0.38. Remifentanil groups showed positive scores in the NPS (0–10 during the CPM-task, that is, it produced a disengagement of

  13. A High-Performing Direct Carbon Fuel Cell with a 3D Architectured Anode Operated Below 600 °C.

    Science.gov (United States)

    Wu, Wei; Zhang, Yunya; Ding, Dong; He, Ting

    2018-01-01

    Direct carbon fuel cells (DCFCs) are highly efficient power generators fueled by abundant and cheap solid carbons. However, the limited triple-phase boundaries (TPBs) in the fuel electrode, due to the lack of direct contact among carbon, electrode, and electrolyte, inhibit the performance and result in poor fuel utilization. To address the challenges of low carbon oxidation activity and low carbon utilization, a highly efficient, 3D solid-state architected anode is developed to enhance the performance of DCFCs below 600 °C. The cell with the 3D textile anode framework, Gd:CeO 2 -Li/Na 2 CO 3 composite electrolyte, and Sm 0.5 Sr 0.5 CoO 3 cathode demonstrates excellent performance with maximum power densities of 143, 196, and 325 mW cm -2 at 500, 550, and 600 °C, respectively. At 500 °C, the cells can be operated steadily with a rated power density of ≈0.13 W cm -2 at a constant current density of 0.15 A cm -2 with a carbon utilization over 85.5%. These results, for the first time, demonstrate the feasibility of directly electrochemical oxidation of solid carbon at 500-600 °C, representing a promising strategy in developing high-performing fuel cells and other electrochemical systems via the integration of 3D architected electrodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Noninvasive brain stimulation with transcranial magnetic or direct current stimulation (TMS/tDCS)-From insights into human memory to therapy of its dysfunction.

    Science.gov (United States)

    Sparing, Roland; Mottaghy, Felix M

    2008-04-01

    Noninvasive stimulation of the brain by means of transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) has driven important discoveries in the field of human memory functions. Stand-alone or in combination with other brain mapping techniques noninvasive brain stimulation can assess issues such as location and timing of brain activity, connectivity and plasticity of neural circuits and functional relevance of a circumscribed brain area to a given cognitive task. In this emerging field, major advances in technology have been made in a relatively short period. New stimulation protocols and, especially, the progress in the application of tDCS have made it possible to obtain longer and much clearer inhibitory or facilitatory effects even after the stimulation has ceased. In this introductory review, we outline the basic principles, discuss technical limitations and describe how noninvasive brain stimulation can be used to study human memory functions in vivo. Though improvement of cognitive functions through noninvasive brain stimulation is promising, it still remains an exciting challenge to extend the use of TMS and tDCS from research tools in neuroscience to the treatment of neurological and psychiatric patients.

  15. Development of materials for use in solid oxid fuel cells anodes using renewable fuels in direct operation

    International Nuclear Information System (INIS)

    Lima, D.B.P.L. de; Florio, D.Z. de; Bezerra, M.E.O.

    2016-01-01

    Fuel cells produce electrical current from the electrochemical combustion of a gas or liquid (H2, CH4, C2H5OH, CH3OH, etc.) inserted into the anode cell. An important class of fuel cells is the SOFC (Solid Oxide Cell Fuel). It has a ceramic electrolyte that transports protons (H +) or O-2 ions and operating at high temperatures (500-1000 °C) and mixed conductive electrodes (ionic and electronic) ceramics or cermets. This work aims to develop anodes for fuel cells of solid oxide (SOFC) in order to direct operations with renewable fuels and strategic for the country (such as bioethanol and biogas). In this context, it becomes important to study in relation to the ceramic materials, especially those that must be used in high temperatures. Some types of double perovskites such as Sr2MgMoO6 (or simply SMMO) have been used as anodes in SOFC. In this study were synthesized by the polymeric precursor method, analyzed and characterized different ceramic samples of families SMMO, doped with Nb, this is: Sr2 (MgMo)1-xNbxO6 with 0 ≤ x ≤ 0.2. The materials produced were characterized by various techniques such as, thermal analysis, X-ray diffraction and scanning electron microscopy, and electrical properties determined by dc and ac measurements in a wide range of temperature, frequency and partial pressure of oxygen. The results of this work will contribute to a better understanding of advanced ceramic properties with mixed driving (electronic and ionic) and contribute to the advancement of SOFC technology operating directly with renewable fuels. (author)

  16. Facile synthesis of Ni-decorated multi-layers graphene sheets as effective anode for direct urea fuel cells

    Directory of Open Access Journals (Sweden)

    Ahmed Yousef

    2017-09-01

    Full Text Available A large amount of urea-containing wastewater is produced as a by-product in the fertilizer industry, requiring costly and complicated treatment strategies. Considering that urea can be exploited as fuel, this wastewater can be treated and simultaneously exploited as a renewable energy source in a direct urea fuel cell. In this study, multi-layers graphene/nickel nanocomposites were prepared by a one-step green method for use as an anode in the direct urea fuel cell. Typically, commercial sugar was mixed with nickel(II acetate tetrahydrate in distilled water and then calcined at 800 °C for 1 h. Raman spectroscopy, X-ray diffraction (XRD, scanning electron microscope (SEM, transmission electron microscope (TEM and energy dispersive spectroscopy (EDS were employed to characterize the final product. The results confirmed the formation of multi-layers graphene sheets decorated by nickel nanoparticles. To investigate the influence of metal nanoparticles content, samples were prepared using different amounts of the metal precursor; nickel acetate content was changed from 0 to 5 wt.%. Investigation of the electrochemical characterizations indicated that the sample prepared using the original solution with 3 wt.% nickel acetate had the best current density, 81.65 mA/cm2 in a 0.33 M urea solution (in 1 M KOH at an applied voltage 0.9 V vs Ag/AgCl. In a passive direct urea fuel cell based on the optimal composition, the observed maximum power density was 4.06 × 10−3 mW/cm2 with an open circuit voltage of 0.197 V at room temperature in an actual electric circuit. Overall, this study introduces a cheap and beneficial methodology to prepare effective anode materials for direct urea fuel cells.

  17. Electrochemical degradation of Novacron Yellow C-RG using boron-doped diamond and platinum anodes: Direct and Indirect oxidation

    International Nuclear Information System (INIS)

    Rocha, J.H. Bezerra; Gomes, M.M. Soares; Santos, E. Vieira dos; Moura, E.C. Martins de; Silva, D. Ribeiro da; Quiroz, M.A.; Martínez-Huitle, C.A.

    2014-01-01

    Graphical abstract: - Highlights: • Nature of electrode material decides the electrocatalytic mechanism followed. • Electrogenerated strong oxidants on BDD surface improve the color and organic load removal. • Chlorine active species act in solution cage oxidizing organic matter. - Abstract: The present study discusses the electrochemical degradation process of a textile dye, Novacron Yellow C-RG (NY), dissolved in synthetic wastewaters, via direct and indirect oxidation. Experiments were conducted using boron-doped diamond (BDD) and platinum supported on Ti (Pt/Ti) electrodes in the absence and presence of NaCl in the solution. The direct process for removing color is relatively similar for both anodes, while the electrochemical degradation is significantly accelerated by the presence of halogen salt in the solution. Interestingly, it does not depend on applied current density, but rather on NaCl concentration. Therefore, the electrochemical processes (direct/indirect) favor specific oxidation pathways depending on electrocatalytic material. Whereas, the Pt/Ti anode favors preferentially color removal by direct and indirect oxidation (100% of color removal) due to the fragmentation of the azo dye group; BDD electrode favors color and organic load removals in both processes (95% and up to 87%, respectively), due to the rupture of dye in different parts of its chemical structure. Parameters of removal efficiency and energy consumption for the electrochemical process were estimated. Finally, an explanation has been attempted for the role of halide, in relation with the oxygen evolution reaction, concomitant with the electrochemical incineration as well as electrocatalytic mechanisms, for each one of the electrodes used

  18. Direct ethanol fuel cells based on PtSn anodes: the effect of Sn content on the fuel cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, W.J.; Song, S.Q.; Li, W.Z.; Zhou, Z.H.; Sun, G.Q.; Xin, Q. [Direct alcohol fuel cell lab, Dalian Institute of Chemical Physics, CAS, P.O. Box 110, Dalian 116023 (China); Douvartzides, S.; Tsiakaras, P. [Department of Mechanical and Industrial Engineering, School of Engineering, University of Thessaly, Pedion Areos, 38334 Volos (Greece)

    2005-01-10

    In the present work, several carbon supported PtSn catalysts with different Pt/Sn atomic ratios were synthesized and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Both the results of TEM and XRD showed that all in-house prepared carbon supported Pt and PtSn catalysts had nanosized particles with narrow size distribution. According to the primary analysis of XPS results, it was confirmed that the main part of Pt of the as-prepared catalysts is in metallic state while the main part of Sn is in oxidized state. The performances of single direct ethanol fuel cells were different from each other with different anode catalysts and at different temperatures. It was found that, the single DEFC employing Pt{sub 3}Sn{sub 2}/C showed better performance at 60{sup o}C while the direct ethanol fuel cells with Pt{sub 2}Sn{sub 1}/C and Pt{sub 3}Sn{sub 2}/C exhibited similar performances at 75{sup o}C. Furthermore, at 90{sup o}C, Pt{sub 2}Sn{sub 1}/C was identified as a more suitable anode catalyst for direct ethanol fuel cells in terms of the fuel cell maximum power density. Surface oxygen-containing species, lattice parameters and ohmic effects, which are related to the Sn content, are thought as the main factors influencing the catalyst activity and consequently the performance of single direct ethanol fuel cells. (author)

  19. Clinically Effective Treatment of Fibromyalgia Pain With High-Definition Transcranial Direct Current Stimulation: Phase II Open-Label Dose Optimization.

    Science.gov (United States)

    Castillo-Saavedra, Laura; Gebodh, Nigel; Bikson, Marom; Diaz-Cruz, Camilo; Brandao, Rivail; Coutinho, Livia; Truong, Dennis; Datta, Abhishek; Shani-Hershkovich, Revital; Weiss, Michal; Laufer, Ilan; Reches, Amit; Peremen, Ziv; Geva, Amir; Parra, Lucas C; Fregni, Felipe

    2016-01-01

    Despite promising preliminary results in treating fibromyalgia (FM) pain, no neuromodulation technique has been adopted in clinical practice because of limited efficacy, low response rate, or poor tolerability. This phase II open-label trial aims to define a methodology for a clinically effective treatment of pain in FM by establishing treatment protocols and screening procedures to maximize efficacy and response rate. High-definition transcranial direct current stimulation (HD-tDCS) provides targeted subthreshold brain stimulation, combining tolerability with specificity. We aimed to establish the number of HD-tDCS sessions required to achieve a 50% FM pain reduction, and to characterize the biometrics of the response, including brain network activation pain scores of contact heat-evoked potentials. We report a clinically significant benefit of a 50% pain reduction in half (n = 7) of the patients (N = 14), with responders and nonresponders alike benefiting from a cumulative effect of treatment, reflected in significant pain reduction (P = .035) as well as improved quality of life (P = .001) over time. We also report an aggregate 6-week response rate of 50% of patients and estimate 15 as the median number of HD-tDCS sessions to reach clinically meaningful outcomes. The methodology for a pivotal FM neuromodulation clinical trial with individualized treatment is thus supported. Registered in Clinicaltrials.gov under registry number NCT01842009. In this article, an optimized protocol for the treatment of fibromyalgia pain with targeted subthreshold brain stimulation using high-definition transcranial direct current stimulation is outlined. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  20. Pt and Ru X-ray absorption spectroscopy of PtRu anode catalysts in operating direct methanol fuel cells.

    Science.gov (United States)

    Stoupin, Stanislav; Chung, Eun-Hyuk; Chattopadhyay, Soma; Segre, Carlo U; Smotkin, Eugene S

    2006-05-25

    In situ X-ray absorption spectroscopy, ex situ X-ray fluorescence, and X-ray powder diffraction enabled detailed core analysis of phase segregated nanostructured PtRu anode catalysts in an operating direct methanol fuel cell (DMFC). No change in the core structures of the phase segregated catalyst was observed as the potential traversed the current onset potential of the DMFC. The methodology was exemplified using a Johnson Matthey unsupported PtRu (1:1) anode catalyst incorporated into a DMFC membrane electrode assembly. During DMFC operation the catalyst is essentially metallic with half of the Ru incorporated into a face-centered cubic (FCC) Pt alloy lattice and the remaining half in an amorphous phase. The extended X-ray absorption fine structure (EXAFS) analysis suggests that the FCC lattice is not fully disordered. The EXAFS indicates that the Ru-O bond lengths were significantly shorter than those reported for Ru-O of ruthenium oxides, suggesting that the phases in which the Ru resides in the catalysts are not similar to oxides.

  1. Effect of the thickness of the anode electrode catalyst layers on the performance in direct methanol fuel cells

    Science.gov (United States)

    Glass, Dean E.; Olah, George A.; Prakash, G. K. Surya

    2017-06-01

    For the large scale fuel cell manufacture, the catalyst loading and layer thickness are critical factors affecting the performance and cost of membrane electrode assemblies (MEAs). The influence of catalyst layer thicknesses at the anode of a PEM based direct methanol fuel cell (DMFC) has been investigated. Catalysts were applied with the drawdown method with varied thicknesses ranging from 1 mil to 8 mils (1 mil = 25.4 μm) with a Pt/Ru anode loading of 0.25 mg cm-2 to 2.0 mg cm-2. The MEAs with the thicker individual layers (8 mils and 4 mils) performed better overall compared to the those with the thinner layers (1 mil and painted). The peak power densities for the different loading levels followed an exponential decrease of Pt/Ru utilization at the higher loading levels. The highest power density achieved was 49 mW cm-2 with the 4 mil layers at 2.0 mg cm-2 catalyst loading whereas the highest normalized power density was 116 mW mg-1 with the 8 mil layers at 0.25 mg cm-2 loading. The 8 mil drawdowns displayed a 50% and 23% increase in normalized power density compared to the 1 mil drawdowns at 0.25 mg cm-2 and 0.5 mg cm-2 loadings, respectively.

  2. A High-Performing Sulfur-Tolerant and Redox-Stable Layered Perovskite Anode for Direct Hydrocarbon Solid Oxide Fuel Cells

    Science.gov (United States)

    Ding, Hanping; Tao, Zetian; Liu, Shun; Zhang, Jiujun

    2015-01-01

    Development of alternative ceramic oxide anode materials is a key step for direct hydrocarbon solid oxide fuel cells (SOFCs). Several lanthanide based layered perovskite-structured oxides demonstrate outstanding oxygen diffusion rate, favorable electronic conductivity, and good oxygen surface exchange kinetics, owing to A-site ordered structure in which lanthanide and alkali-earth ions occupy alternate (001) layers and oxygen vacancies are mainly located in [LnOx] planes. Here we report a nickel-free cation deficient layered perovskite, (PrBa)0.95(Fe0.9Mo0.1)2O5 + δ (PBFM), for SOFC anode, and this anode shows an outstanding performance with high resistance against both carbon build-up and sulfur poisoning in hydrocarbon fuels. At 800 °C, the layered PBFM showed high electrical conductivity of 59.2 S cm−1 in 5% H2 and peak power densities of 1.72 and 0.54 W cm−2 using H2 and CH4 as fuel, respectively. The cell exhibits a very stable performance under a constant current load of 1.0 A cm−2. To our best knowledge, this is the highest performance of ceramic anodes operated in methane. In addition, the anode is structurally stable at various fuel and temperature conditions, suggesting that it is a feasible material candidate for high-performing SOFC anode. PMID:26648509

  3. 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.

  4. Effects of Unilateral Transcranial Direct Current Stimulation of Left Prefrontal Cortex on Processing and Memory of Emotional Visual Stimuli.

    Science.gov (United States)

    Balzarotti, Stefania; Colombo, Barbara

    2016-01-01

    The dorsolateral prefrontal cortex (DLPFC) is generally thought to be involved in affect and emotional processing; however, the specific contribution of each hemisphere continues to be debated. In the present study, we employed unilateral tDCS to test the unique contribution of left DLPFC in the encoding and retrieval of emotional stimuli in healthy subjects. Forty-two right handed undergraduate students received either anodal, cathodal or sham stimulation of left DLPFC while viewing neutral, pleasant, and unpleasant pictures. After completing a filler task, participants were asked to remember as many pictures as possible. Results showed that participants were able to remember a larger amount of emotional (both pleasant and unpleasant) pictures than of neutral ones, regardless of the type of tDCS condition. Participants who received anodal stimulation recalled a significantly higher number of pleasant images than participants in the sham and cathodal conditions, while no differences emerged in the recall of neutral and unpleasant pictures. We conclude that our results provide some support to the role of left prefrontal cortex in the encoding and retrieval of pleasant stimuli.

  5. Effects of Unilateral Transcranial Direct Current Stimulation of Left Prefrontal Cortex on Processing and Memory of Emotional Visual Stimuli.

    Directory of Open Access Journals (Sweden)

    Stefania Balzarotti

    Full Text Available The dorsolateral prefrontal cortex (DLPFC is generally thought to be involved in affect and emotional processing; however, the specific contribution of each hemisphere continues to be debated. In the present study, we employed unilateral tDCS to test the unique contribution of left DLPFC in the encoding and retrieval of emotional stimuli in healthy subjects. Forty-two right handed undergraduate students received either anodal, cathodal or sham stimulation of left DLPFC while viewing neutral, pleasant, and unpleasant pictures. After completing a filler task, participants were asked to remember as many pictures as possible. Results showed that participants were able to remember a larger amount of emotional (both pleasant and unpleasant pictures than of neutral ones, regardless of the type of tDCS condition. Participants who received anodal stimulation recalled a significantly higher number of pleasant images than participants in the sham and cathodal conditions, while no differences emerged in the recall of neutral and unpleasant pictures. We conclude that our results provide some support to the role of left prefrontal cortex in the encoding and retrieval of pleasant stimuli.

  6. No evidence for enhancements to visual working memory with transcranial direct current stimulation to prefrontal or posterior parietal cortices.

    Science.gov (United States)

    Robison, Matthew K; McGuirk, William P; Unsworth, Nash

    2017-08-01

    The present study examined the relative contributions of the prefrontal cortex (PFC) and posterior parietal cortex (PPC) to visual working memory. Evidence from a number of different techniques has led to the theory that the PFC controls access to working memory (i.e., filtering), determining which information is encoded and maintained for later use whereas the parietal cortex determines how much information is held at 1 given time, regardless of relevance (i.e., capacity; McNab & Klingberg, 2008; Vogel, McCollough, & Machizawa, 2005). To test this theory, we delivered transcranial DC stimulation (tDCS) to the right PFC and right PPC and measured visual working memory capacity and filtering abilities both during and immediately following stimulation. We observed no evidence that tDCS to either the PFC or PPC significantly improved visual working memory. Although the present results did not allow us to make firm theoretical conclusions about the roles of the PFC and PPC in working memory, the results add to the growing body of literature surrounding tDCS and its associated behavioral and neurophysiological effects. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  7. Improvement of Upper Extremity Deficit after Constraint-Induced Movement Therapy Combined with and without Preconditioning Stimulation Using Dual-hemisphere Transcranial Direct Current Stimulation and Peripheral Neuromuscular Stimulation in Chronic Stroke Patients: A Pilot Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Takashi Takebayashi

    2017-10-01

    Full Text Available In this study, we investigated the effects of dual-hemisphere transcranial direct current stimulation (dual-tDCS of both the affected (anodal tDCS and non-affected (cathodal tDCS primary motor cortex, combined with peripheral neuromuscular electrical stimulation (PNMES, on the effectiveness of constraint-induced movement therapy (CIMT as a neurorehabilitation intervention in chronic stroke. We conducted a randomized controlled trial of feasibility, with a single blind assessor, with patients recruited from three outpatient clinics. Twenty chronic stroke patients were randomly allocated to the control group, receiving conventional CIMT, or the intervention group receiving dual-tDCS combined with PNMES before CIMT. Patients in the treatment group first underwent a 20-min period of dual-tDCS, followed immediately by PNMES, and subsequent CIMT for 2 h. Patients in the control group only received CIMT (with no pretreatment stimulation. All patients underwent two CIMT sessions, one in the morning and one in the afternoon, each lasting 2 h, for a total of 4 h of CIMT per day. Upper extremity function was assessed using the Fugl-Meyer Assessment (primary outcome, as well as the amount of use (AOU and quality of movement (QOM scores, obtained via the Motor Activity Log (secondary outcome. Nineteen patients completed the study, with one patient withdrawing after allocation. Compared to the control group, the treatment improvement in upper extremity function and AOU was significantly greater in the treatment than control group (change in upper extremity score, 9.20 ± 4.64 versus 4.56 ± 2.60, respectively, P < 0.01, η2 = 0.43; change in AOU score, 1.10 ± 0.65 versus 0.62 ± 0.85, respectively, P = 0.02, η2 = 0.52. There was no significant effect of the intervention on the QOM between the intervention and control groups (change in QOM score, 1.00 ± 0.62 versus 0.71 ± 0.72, respectively, P = 0.07, η2

  8. PsychotherapyPlus: augmentation of cognitive behavioral therapy (CBT) with prefrontal transcranial direct current stimulation (tDCS) in major depressive disorder-study design and methodology of a multicenter double-blind randomized placebo-controlled trial.

    Science.gov (United States)

    Bajbouj, Malek; Aust, Sabine; Spies, Jan; Herrera-Melendez, Ana-Lucia; Mayer, Sarah V; Peters, Maike; Plewnia, Christian; Fallgatter, Andreas J; Frase, Lukas; Normann, Claus; Behler, Nora; Wulf, Linda; Brakemeier, Eva-Lotta; Padberg, Frank

    2017-12-06

    Major Depressive Disorder (MDD) is one of the most prevalent psychiatric disorders worldwide. About 20-30% of patients do not respond to the standard psychopharmacological and/or psychotherapeutic interventions. Mounting evidence from neuroimaging studies in MDD patients reveal altered activation patterns in lateral prefrontal brain areas. Successful cognitive behavioral therapy (CBT) is associated with a recovery of these neural alterations. Moreover, it has been demonstrated that transcranial direct current stimulation (tDCS) is capable of influencing prefrontal cortex activity and cognitive functions such as working memory and emotion regulation. Thus, a clinical trial investigating the effects of an antidepressant intervention combining CBT with tDCS seems promising. The present study investigates the antidepressant efficacy of a combined CBT-tDCS intervention as compared to CBT with sham-tDCS or CBT alone. A total of 192 patients (age range 20-65 years) with MDD (Hamilton Depression Rating Scale Score ≥ 15, 21-item version) will be recruited at four study sites across Germany (Berlin, Munich, Tuebingen, and Freiburg) and randomly assigned to one of the following three treatment arms: (1) CBT + active tDCS; (2) CBT + sham-tDCS; and (3) CBT alone. All participants will attend a 6-week psychotherapeutic intervention comprising 12 sessions of CBT each lasting 100 min in a closed group setting. tDCS will be applied simultaneously with CBT. Active tDCS includes stimulation with an intensity of 2 mA for 30 min with the anode placed over F3 and the cathode over F4 according to the EEG 10-20 system, if assigned. The primary outcome measure is the change in Montgomery-Åsberg Depression Rating Scale scores from baseline to 6, 18, and 30 weeks after the first session. Participants also undergo pre- and post-treatment neuropsychological testing and functional magnetic resonance imaging (fMRI) to assess changes in prefrontal functioning and connectivity

  9. PtM/C (M = Sn, Ru, Pd, W) based anode direct ethanol-PEMFCs: Structural characteristics and cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Tsiakaras, P.E. [Department of Mechanical Engineering, School of Engineering, University of Thessaly, Pedion Areos, 38334 Volos (Greece)

    2007-09-19

    In the present work, the role of the structural characteristics of Pt-based catalysts on the single direct ethanol proton exchange membrane fuel cell (PEMFC) performance is examined. Several PtM/C (M = Sn, Ru, Pd, W) catalysts were characterized by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD) and then evaluated as anode catalysts in single direct ethanol fuel cells. XRD spectra showed that Pt lattice parameter decreases with the addition of Ru or Pd and increases with the addition of Sn or W. According to the obtained experimental results, PtSn catalysts presented better electrocatalytic activity towards ethanol electro-oxidation. Based on these results, PtSn/C catalysts with different Pt/Sn atomic ratio were tested and compared. The maximum power density values obtained were correlated with the structural characteristics of the catalysts. A volcano type behaviour between the fuel cell maximum power density and the corresponding atomic percentage of Sn (Sn%) was observed. It was also observed that Sn% affects almost linearly the Pt{sub x}Sn{sub y} catalysts' lattice parameter. (author)

  10. A robust NiO-Sm0.2Ce0.8O1.9 anode for direct-methane solid oxide fuel cell

    KAUST Repository

    Tian, Dong

    2015-07-02

    In order to directly use methane without a reforming process, NiO-Sm0.2Ce0.8O1.9 (NiO-SDC) nanocomposite anode are successfully synthesized via a one-pot, surfactant-assisted co-assembly approach for direct-methane solid oxide fuel cells. Both NiO with cubic phase and SDC with fluorite phase are obtained at 550 °C. Both NiO nanoparticles and SDC nanoparticles are highly monodispersed in size with nearly spherical shapes. Based on the as-synthesized NiO-SDC, two kinds of single cells with different micro/macro-porous structure are successfully fabricated. As a result, the cell performance was improved by 40%-45% with the new double-pore NiO-SDC anode relative to the cell performance with the conventional NiO-SDC anode due to a wider triple-phase-boundary (TPB) area. In addition, no significant degradation of the cell performance was observed after 60 hours, which means an increasing of long term stability. Therefore, the as-synthesized NiO-SDC nanocomposite is a promising anode for direct-methane solid oxide fuel cells.

  11. Preparation and characterization of anode catalysts for the direct alcohol fuel cells (DAFC): methanol and ethanol

    CSIR Research Space (South Africa)

    Modibedi, M

    2007-11-01

    Full Text Available The development of high performance electrode materials has been the key research objective in the field of direct alcohol fuel cells (DAFC) [1, 2, and 3]. A promising way to attain higher catalytic performance is to add a third element to the best...

  12. Efficacy of transcranial direct current stimulation combined with cognitive training in the treatment of apathy in patients with Alzheimer's disease: study protocol for a randomized trial.

    Science.gov (United States)

    Nguyen, Jean-Paul; Boutoleau-Bretonniere, Claire; Lefaucheur, Jean-Pascal; Suarez, Alcira; Gaillard, Helene; Chapelet, Guillaume; Abad, Sebastien; Van Langhenhove, Aurelien; Nizard, Julian; de Decker, Laure

    2018-04-16

    Apathy, commonly defined as loss of motivation, is a symptom frequently encountered in Alzheimer's disease (AD). The treatment of apathy remains challenging in the absence of any truly effective medications. Transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) can improve cognitive disorders, but do not appear to improve apathy. Isolated cognitive training also appears to have no effect on apathy. We propose to test the efficacy of a new procedure for the treatment of apathy in AD patients consisting of a combination of tDCS and cognitive training, based on the latest guidelines for the design of therapeutic trials in this field. This article primarily describes the design of a monocentre, randomized, double-blind trial to be conducted in France to evaluate the effect of the combination of tDCS and cognitive training on apathy compared to a group treated exclusively by cognitive training (sham tDCS). Twenty-four patients under the age of 90 years with mild-to-moderate Alzheimer's disease (Mini Mental State Examination score between 15 and 26/30) (MMSE)) presenting clinically significant apathy evaluated by the Apathy Inventory (AI) and the NeuroPsychiatric Inventory (NPI) apathy subscore will be enrolled. Severe depression will be excluded by using the NPI depression subscore. Treatment will comprise 10 sessions (D0-D11) including tDCS (bilateral prefrontal, temporal and parietal targets) and cognitive training (Cog) (6 simple tasks involving working memory, language and visuospatial function). After randomization (ratio 2:1), 16 patients will receive the complete treatment comprising tDCS and Cog (group 1) and 8 patients will be treated exclusively by Cog (sham tDCS) (group 2). The primary endpoint will be a significant improvement of the AI score by comparing baseline measures (D-15) to those recorded one month after stopping treatment (D44). Secondary endpoints will be an improvement of this score immediately after treatment

  13. 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...

  14. Early adopters of the magical thinking cap: a study on do-it-yourself (DIY) transcranial direct current stimulation (tDCS) user community.

    Science.gov (United States)

    Jwa, Anita

    2015-07-01

    Among currently available technologies, transcranial direct current stimulation (tDCS) is one of the most promising neuroenhancements because it is relatively effective, safe, and affordable. Recently, lay people have begun to build-or purchase-the tDCS device to use it at home for treatment or as a cognitive enhancer. The tDCS device is currently not covered by the existing regulatory framework, but there are still significant potential risks of misusing this device, and its long-term effects on the brain have not been fully explored. Thus, researchers have argued the need for regulations or official guidelines for the personal use of tDCS. However, until now, no systematic research on the do-it-yourself (DIY) tDCS user community has been done. The present study explores the basic demographic characteristics of DIY tDCS users as well as why and how they are using this device through a questionnaire survey, in-depth interviews, and a content analysis of web postings on the use of tDCS. This preliminary but valuable picture of the DIY tDCS user community will shed light on future studies and policy analysis to craft sound regulations and official guidelines for the use of tDCS.

  15. Integrated treatment modality of cathodal-transcranial direct current stimulation with peripheral sensory stimulation affords neuroprotection in a rat stroke model.

    Science.gov (United States)

    Liu, Yu-Hang; Chan, Su Jing; Pan, Han-Chi; Bandla, Aishwarya; King, Nicolas K K; Wong, Peter Tsun Hon; Chen, You-Yin; Ng, Wai Hoe; Thakor, Nitish V; Liao, Lun-De

    2017-10-01

    Cathodal-transcranial direct current stimulation induces therapeutic effects in animal ischemia models by preventing the expansion of ischemic injury during the hyperacute phase of ischemia. However, its efficacy is limited by an accompanying decrease in cerebral blood flow. On the other hand, peripheral sensory stimulation can increase blood flow to specific brain areas resulting in rescue of neurovascular functions from ischemic damage. Therefore, the two modalities appear to complement each other to form an integrated treatment modality. Our results showed that hemodynamics was improved in a photothrombotic ischemia model, as cerebral blood volume and hemoglobin oxygen saturation ([Formula: see text]) recovered to 71% and 76% of the baseline values, respectively. Furthermore, neural activities, including somatosensory-evoked potentials (110% increase), the alpha-to-delta ratio (27% increase), and the [Formula: see text] ratio (27% decrease), were also restored. Infarct volume was reduced by 50% with a 2-fold preservation in the number of neurons and a 6-fold reduction in the number of active microglia in the infarct region compared with the untreated group. Grip strength was also better preserved (28% higher) compared with the untreated group. Overall, this nonpharmacological, nonintrusive approach could be prospectively developed into a clinical treatment modality.

  16. 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.

  17. 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, Phallucinations 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.

  18. Elementary kinetic modelling applied to solid oxide fuel cell pattern anodes and a direct flame fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Vogler, Marcel

    2009-05-27

    In the course of this thesis a model for the prediction of polarisation characteristics of solid oxide fuel cells (SOFC) was developed. The model is based on an elementary kinetic description of electrochemical reactions and the fundamental conservation principles of mass and energy. The model allows to predict the current-voltage relation of an SOFC and offers ideal possibilities for model validation. The aim of this thesis is the identification of rate-limiting processes and the determination of the elementary pathway during charge transfer. The numerical simulation of experiments with model anodes allowed to identify a hydrogen transfer to be the most probable charge-transfer reaction and revealed the influence of diffusive transport. Applying the hydrogen oxidation kinetics to the direct flame fuel cell system (DFFC) showed that electrochemical oxidation of CO is possible based on the same mechanism. Based on the quantification of loss processes in the DFFC system, improvements on cell design, predicting 80% increase of efficiency, were proposed. (orig.)

  19. Direct ceramic inkjet printing of yttria-stabilized zirconia electrolyte layers for anode-supported solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Tomov, R.I.; Hopkins, S.C. [Applied Superconductivity and Cryoscience Group, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB4 3QZ (United Kingdom); Krauz, M.; Kluczowski, J.R. [Institute of Power Engineering, Ceramic Department CEREL, 36-040 Boguchwala (Poland); Jewulski, J. [Institute of Power Engineering, Fuel Cells Department, 02-981 Warsaw (Poland); Glowacka, D.M. [Detector Physics Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE (United Kingdom); Glowacki, B.A. [Applied Superconductivity and Cryoscience Group, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB4 3QZ (United Kingdom); Institute of Power Engineering, Fuel Cells Department, 02-981 Warsaw (Poland)

    2010-11-01

    Electromagnetic drop-on-demand direct ceramic inkjet printing (EM/DCIJP) was employed to fabricate dense yttria-stabilized zirconia (YSZ) electrolyte layers on a porous NiO-YSZ anode support from ceramic suspensions. Printing parameters including pressure, nozzle opening time and droplet overlapping were studied in order to optimize the surface quality of the YSZ coating. It was found that moderate overlapping and multiple coatings produce the desired membrane quality. A single fuel cell with a NiO-YSZ/YSZ ({proportional_to}6 {mu}m)/LSM + YSZ/LSM architecture was successfully prepared. The cell was tested using humidified hydrogen as the fuel and ambient air as the oxidant. The cell provided a power density of 170 mW cm{sup -2} at 800 C. Scanning electron microscopy (SEM) revealed a highly coherent dense YSZ electrolyte layer with no open porosity. These results suggest that the EM/DCIJP inkjet printing technique can be successfully implemented to fabricate electrolyte coatings for SOFC thinner than 10 {mu}m and comparable in quality to those fabricated by more conventional ceramic processing methods. (author)

  20. Transcranial Extracellular Impedance Control (tEIC) Modulates Behavioral Performances

    OpenAIRE

    Matani, Ayumu; Nakayama, Masaaki; Watanabe, Mayumi; Furuyama, Yoshikazu; Hotta, Atsushi; Hoshino, Shotaro

    2014-01-01

    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 distri...

  1. High throughput evaluation of perovskite-based anode catalysts for direct methanol fuel cells

    Science.gov (United States)

    Deshpande, Kishori; Mukasyan, Alexander; Varma, Arvind

    Liquid feed direct methanol fuel cells (DMFC) are promising candidates for portable power applications. However, owing to the problems associated with expensive Pt-based catalysts, viz., CO poisoning, a promising approach is to use complex oxides of the type ABO 3 (A = Sr, Ce, La, etc. and B = Co, Fe, Ni, Pt, Ru, etc.). In the current work, a variety of ABO 3 and A 2BO 4 type non-noble and partially substituted noble metal high surface area compounds were synthesized by an effective and rapid aqueous combustion synthesis (CS). Their catalytic activity was evaluated by using "High Throughput Screening Unit"-NuVant System, which compares up to 25 compositions simultaneously under DMFC conditions. It was found that the Sr-based perovskites showed performance comparable with the standard Pt-Ru catalyst. Further, it was observed that the method of doping SrRuO 3 with Pt influenced the activity. Specifically, platinum added during aqueous CS yielded better catalyst than when added externally at the ink preparation stage. Finally, it was also demonstrated that the presence of SrRuO 3 significantly enhanced the catalytic properties of Pt, leading to superior performance even at lower noble metal loadings.

  2. Development of Anodic Flux and Temperature Controlling System for Micro Direct Methanol Fuel Cell

    Science.gov (United States)

    Li, M. M.; Liu, C.; Liang, J. S.; Wu, C. B.; Xu, Z.

    2006-10-01

    Micro Direct Methanol Fuel Cell (μDMFC) is a kind of newly developed power sources, which effective apparatus for its performance evaluation is still in urgent need at present. In this study, a testing system was established for the purpose of testing the continuous working performance such as micro flux and temperature of μDMFC. In view of the temperature controlling for micro-flux liquid fuel, a heating block with labyrinth-like single pass channel inside for heating up the methanol solution was fabricated. A semiconductorrefrigerating chip was utilized to heat and cool the liquid flow during testing procedures. On the other hand, the two channels of a high accuracy double-channel syringe pump that can suck and pump in turn so as to transport methanol solution continuously was adopted. Based on the requirements of wide-ranged temperature and micro flux controlling, the solenoid valves and the correlative component were used. A hydraulic circuit, which can circulate the fed methanol cold to hot in turn, has also been constructed to test the fatigue life of the μDMFC. The automatic control was actualized by software module written with Visual C++. Experimental results show that the system is perfect in stability and it may provide an important and advanced evaluation apparatus to satisfy the needs for real time performance testing of μDMFC.

  3. Interleaved mesoporous copper for the anode catalysis in direct ammonium borane fuel cells.

    Science.gov (United States)

    Auxilia, Francis M; Tanabe, Toyokazu; Ishihara, Shinsuke; Saravanan, Govindachetty; Ramesh, Gubbala V; Matsumoto, Futoshi; Ya, Xu; Ariga, Katsuhiko; Dakshanamoorthy, Arivuoli; Abe, Hideki

    2014-06-01

    Mesoporous materials with tailored microstructures are of increasing importance in practical applications particularly for energy generation and/or storage. Here we report a mesoporous copper material (MS-Cu) can be prepared in a hierarchical microstructure and exhibit high catalytic performance for the half-cell reaction of direct ammonium borane (NH3BH3) fuel cells (DABFs). Hierarchical copper oxide (CuO) nanoplates (CuO Npls) were first synthesized in a hydrothermal condition. CuO Npls were then reduced at room temperature using water solution of sodium borohydride (NaBH4) to yield the desired mesoporous copper material, MS-Cu, consisting of interleaved nanoplates with a high density of mesopores. The surface of MS-Cu comprised high-index facets, whereas a macroporous copper material (MC-Cu), which was prepared from CuO Npls at elevated temperatures in a hydrogen stream, was surrounded by low-index facets with a low density of active sites. MS-Cu exhibited a lower onset potential and improved durability for the electro-oxidation of NH3BH3 than MC-Cu or copper particles because of the catalytically active mesopores on the interleaved nanoplates.

  4. Quantitative Review Finds No Evidence of Cognitive Effects in Healthy Populations From Single-session Transcranial Direct Current Stimulation (tDCS).

    Science.gov (United States)

    Horvath, Jared Cooney; Forte, Jason D; Carter, Olivia

    2015-01-01

    Over the last 15-years, transcranial direct current stimulation (tDCS), a relatively novel form of neuromodulation, has seen a surge of popularity in both clinical and academic settings. Despite numerous claims suggesting that a single session of tDCS can modulate cognition in healthy adult populations (especially working memory and language production), the paradigms utilized and results reported in the literature are extremely variable. To address this, we conduct the largest quantitative review of the cognitive data to date. Single-session tDCS data in healthy adults (18-50) from every cognitive outcome measure reported by at least two different research groups in the literature was collected. Outcome measures were divided into 4 broad categories: executive function, language, memory, and miscellaneous. To account for the paradigmatic variability in the literature, we undertook a three-tier analysis system; each with less-stringent inclusion criteria than the prior. Standard mean difference values with 95% CIs were generated for included studies and pooled for each analysis. Of the 59 analyses conducted, tDCS was found to not have a significant effect on any - regardless of inclusion laxity. This includes no effect on any working memory outcome or language production task. Our quantitative review does not support the idea that tDCS generates a reliable effect on cognition in healthy adults. Reasons for and limitations of this finding are discussed. This work raises important questions regarding the efficacy of tDCS, state-dependency effects, and future directions for this tool in cognitive research. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Delayed plastic responses to anodal tDCS in older adults

    Science.gov (United States)

    Fujiyama, Hakuei; Hyde, Jane; Hinder, Mark R.; Kim, Seok-Jin; McCormack, Graeme H.; Vickers, James C.; Summers, Jeffery J.

    2014-01-01

    Despite the abundance of research reporting the neurophysiological and behavioral effects of transcranial direct current stimulation (tDCS) in healthy young adults and clinical populations, the extent of potential neuroplastic changes induced by tDCS in healthy older adults is not well understood. The present study compared the extent and time course of anodal tDCS-induced plastic changes in primary motor cortex (M1) in young and older adults. Furthermore, as it has been suggested that neuroplasticity and associated learning depends on the brain-derived neurotrophic factor (BDNF) gene polymorphisms, we also assessed the impact of BDNF polymorphism on these effects. Corticospinal excitability was examined using transcranial magnetic stimulation before and following (0, 10, 20, 30 min) anodal tDCS (30 min, 1 mA) or sham in young and older adults. While the overall extent of increases in corticospinal excitability induced by anodal tDCS did not vary reliably between young and older adults, older adults exhibited a delayed response; the largest increase in corticospinal excitability occurred 30 min following stimulation for older adults, but immediately post-stimulation for the young group. BDNF genotype did not result in significant differences in the observed excitability increases for either age group. The present study suggests that tDCS-induced plastic changes are delayed as a result of healthy aging, but that the overall efficacy of the plasticity mechanism remains unaffected. PMID:24936185

  6. Numerical simulation and analysis of electromagnetic-wave absorption of a plasma slab created by a direct-current discharge with gridded anode

    Science.gov (United States)

    Yuan, Chengxun; Tian, Ruihuan; Eliseev, S. I.; Bekasov, V. S.; Bogdanov, E. A.; Kudryavtsev, A. A.; Zhou, Zhongxiang

    2018-03-01

    In this paper, we present investigation of a direct-current discharge with a gridded anode from the point of view of using it as a means of creating plasma coating that could efficiently absorb incident electromagnetic (EM) waves. A single discharge cell consists of two parallel plates, one of which (anode) is gridded. Electrons emitted from the cathode surface are accelerated in the short interelectrode gap and are injected into the post-anode space, where they lose acquired energy on ionization and create plasma. Numerical simulations were used to investigate the discharge structure and obtain spatial distributions of plasma density in the post-anode space. The numerical model of the discharge was based on a simple hybrid approach which takes into account non-local ionization by fast electrons streaming from the cathode sheath. Specially formulated transparency boundary conditions allowed performing simulations in 1D. Simulations were carried out in air at pressures of 10 Torr and higher. Analysis of the discharge structure and discharge formation is presented. It is shown that using cathode materials with lower secondary emission coefficients can allow increasing the thickness of plasma slabs for the same discharge current, which can potentially enhance EM wave absorption. Spatial distributions of electron density obtained during simulations were used to calculate attenuation of an incident EM wave propagating perpendicularly to the plasma slab boundary. It is shown that plasma created by means of a DC discharge with a gridded anode can efficiently absorb EM waves in the low frequency range (6-40 GHz). Increasing gas pressure results in a broader range of wave frequencies (up to 500 GHz) where a considerable attenuation is observed.

  7. Recurrent themes in the history of the home use of electrical stimulation: Transcranial direct current stimulation (tDCS) and the medical battery (1870-1920).

    Science.gov (United States)

    Wexler, Anna

    In recent years, neuroscientists and ethicists have warned of the dangers of the unsupervised home use of transcranial direct current stimulation (tDCS), in which individuals stimulate their own brains with low levels of electricity for self-improvement purposes. Although the home use of tDCS is often referred to as a novel phenomenon, in reality the late nineteenth and early twentieth century saw a proliferation of electrical stimulation devices for home use. In particular, the use of an object known as the medical battery bears a number of striking similarities to the modern-day use of tDCS. This article reviews a number of features thought to be unique to the present day home use of brain stimulation, with a particular focus on analogies between tDCS and the medical battery. Archival research was conducted at the Bakken Museum and at the American Medical Association's Historical Health Fraud Archives. Many of the features characterizing the contemporary home use tDCS-a do-it-yourself (DIY) movement, anti-medical establishment themes, conflicts between lay and professional usage-are a repetition of themes that occurred a century ago with regard to the medical battery. A number of features, however, seem to be unique to the present, such as the dominant discourse about risk and safety, the division between cranial and non-cranial stimulation, and utilization for cognitive enhancement purposes. Viewed in the long durée, the contemporary use of electrical stimulation at home is not a novel phenomenon, but rather the latest wave in a series of ongoing attempts by lay individuals to utilize electricity for therapeutic purposes. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Transcranial direct current stimulation (tDCS) reveals a dissociation between SNARC and MARC effects: Implication for the polarity correspondence account.

    Science.gov (United States)

    Di Rosa, Elisa; Bardi, Lara; Umiltà, Carlo; Masina, Fabio; Forgione, Margherita; Mapelli, Daniela

    2017-08-01

    The concept of stimulus response compatibility (SRC) refers to the existence of a privileged association between a specific stimulus feature and a specific response feature. Two examples of SRC are the Spatial Numerical Association of Response Codes (SNARC) and the Markedness Association of Response Codes (MARC) effects. According to the polarity correspondence principle, these two SRC effects occur because of a match between the most salient dimensions of stimulus and response. Specifically, the SNARC effect would be caused by a match between right-sided responses and large numbers, while a match between right-sided responses and even numbers would give rise to the MARC effect. The aim of the present study was to test the validity of the polarity correspondence principle in explaining these two SRC effects. To this end, we applied transcranial direct current stimulation (tDCS) over left and right posterior parietal cortex (PPC), which is thought to be the neural basis of salience processing, during a parity judgement task. Results showed that cathodal tDCS over the PPC significantly reduced the MARC effect but did not affect the SNARC effect, suggesting a dissociation between the two effects. That is, the MARC would rely on a salience processing mechanism, whereas the SNARC would not. Despite this interpretation is in need of further experimental confirmations (i.e., testing different tasks or using different tDCS montages), our results suggest that the polarity correspondence principle can be a plausible explanation only for the MARC effect but not for the SNARC effect. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Slow oscillating transcranial direct current stimulation during non-rapid eye movement sleep improves behavioral inhibition in attention-deficit/ hyperactivity disorder

    Directory of Open Access Journals (Sweden)

    Manuel Tobias Munz

    2015-08-01

    Full Text Available Background: Behavioral inhibition, which is a later-developing executive function (EF and anatomically located in prefrontal areas, is impaired in attention-deficit and hyperactivity disorder (ADHD. While optimal EFs have been shown to depend on efficient sleep in healthy subjects, the impact of sleep problems, frequently reported in ADHD, remains elusive. Findings of macroscopic sleep changes in ADHD are inconsistent, but there is emerging evidence for distinct microscopic changes with a focus on prefrontal cortical regions and non-rapid eye movement (non-REM slow-wave sleep. Recently, slow oscillations (SO during non-REM sleep were found to be less functional and, as such, may be involved in sleep-dependent memory impairments in ADHD. Objective: By augmenting slow-wave power through bilateral, slow oscillating transcranial direct current stimulation (so-tDCS, frequency = 0.75 Hz during non-REM sleep, we aimed to improve daytime behavioral inhibition in children with ADHD. Methods: 14 boys (10-14 yrs diagnosed with ADHD were included. In a randomized, double-blind, cross-over design, patients received so-tDCS either in the first or in the second experimental sleep night. Inhibition control was assessed with a visuomotor go/no-go task. Intrinsic alertness was assessed with a simple stimulus response task. To control for visuomotor performance, motor memory was assessed with a finger sequence tapping task. Results: SO-power was enhanced during early non-REM sleep, accompanied by slowed reaction times and decreased standard deviations of reaction times, in the go/no-go task after so-tDCS. In contrast, intrinsic alertness and motor memory performance were not improved by so-tDCS. Conclusion: Since behavioral inhibition but not intrinsic alertness or motor memory was improved by so-tDCS, our results suggest that lateral prefrontal slow oscillations during sleep might play a specific role for executive functioning in ADHD.

  10. 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.

  11. No evidential value in samples of transcranial direct current stimulation (tDCS) studies of cognition and working memory in healthy populations.

    Science.gov (United States)

    Medina, Jared; Cason, Samuel

    2017-09-01

    A substantial number of studies have been published over the last decade, claiming that transcranial direct current stimulation (tDCS) can influence performance on cognitive tasks. However, there is some skepticism regarding the efficacy of tDCS, and evidence from meta-analyses are mixed. One major weakness of these meta-analyses is that they only examine outcomes in published studies. Given biases towards publishing positive results in the scientific literature, there may be a substantial "file-drawer" of unpublished negative results in the tDCS literature. Furthermore, multiple researcher degrees of freedom can also inflate published p-values. Recently, Simonsohn, Nelson and Simmons (2014) created a novel meta-analytic tool that examines the distribution of significant p-values in a literature, and compares it to expected distributions with different effect sizes. Using this tool, one can assess whether the selected studies have evidential value. Therefore, we examined a random selection of studies that used tDCS to alter performance on cognitive tasks, and tDCS studies on working memory in a recently published meta-analysis (Mancuso et al., 2016). Using a p-curve analysis, we found no evidence that the tDCS studies had evidential value (33% power or greater), with the estimate of statistical power of these studies being approximately 14% for the cognitive studies, and 5% (what would be expected from randomly generated data) for the working memory studies. It is likely that previous tDCS studies are substantially underpowered, and we provide suggestions for future research to increase the evidential value of future tDCS studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. 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.

  13. Pharmacological approach to the mechanisms of transcranial DC-stimulation-induced after-effects of human motor cortex excitability.

    Science.gov (United States)

    Liebetanz, David; Nitsche, Michael A; Tergau, Frithjof; Paulus, Walter

    2002-10-01

    Weak transcranial direct current stimulation (tDCS) induces persisting excitability changes in the human motor cortex. These plastic excitability changes are selectively controlled by the polarity, duration and current strength of stimulation. To reveal the underlying mechanisms of direct current (DC)-induced neuroplasticity, we combined tDCS of the motor cortex with the application of Na(+)-channel-blocking carbamazepine (CBZ) and the N-methyl-D-aspartate (NMDA)-receptor antagonist dextromethorphan (DMO). Monitored by transcranial magnetic stimulation (TMS), motor cortical excitability changes of up to 40% were achieved in the drug-free condition. Increase of cortical excitability could be selected by anodal stimulation, and decrease by cathodal stimulation. Both types of excitability change lasted several minutes after cessation of current stimulation. DMO suppressed the post-stimulation effects of both anodal and cathodal DC stimulation, strongly suggesting the involvement of NMDA receptors in both types of DC-induced neuroplasticity. In contrast, CBZ selectively eliminated anodal effects. Since CBZ stabilizes the membrane potential voltage-dependently, the results reveal that after-effects of anodal tDCS require a depolarization of membrane potentials. Similar to the induction of established types of short- or long-term neuroplasticity, a combination of glutamatergic and membrane mechanisms is necessary to induce the after-effects of tDCS. On the basis of these results, we suggest that polarity-driven alterations of resting membrane potentials represent the crucial mechanisms of the DC-induced after-effects, leading to both an alteration of spontaneous discharge rates and to a change in NMDA-receptor activation.

  14. On direct internal methane steam reforming kinetics in operating solid oxide fuel cells with nickel-ceria anodes

    Science.gov (United States)

    Thallam Thattai, A.; van Biert, L.; Aravind, P. V.

    2017-12-01

    Major operating challenges remain to safely operate methane fuelled solid oxide fuel cells due to undesirable temperature gradients across the porous anode and carbon deposition. This article presents an experimental study on methane steam reforming (MSR) global kinetics for single operating SOFCs with Ni-GDC (gadolinium doped ceria) anodes for low steam to carbon (S/C) ratios and moderate current densities. The study points out the hitherto insufficient research on MSR global and intrinsic kinetics for operating SOFCs with complete Ni-ceria anodes. Further, it emphasizes the need to develop readily applicable global kinetic models as a subsequent step from previously reported state-of-art and complex intrinsic models. Two rate expressions of the Power law (PL) and Langmuir-Hinshelwood (LH) type have been compared and based on the analysis, limitations of using previously proposed rate expressions for Ni catalytic beds to study MSR kinetics for complete cermet anodes have been identified. Firstly, it has been shown that methane reforming on metallic (Ni) current collectors may not be always negligible, contrary to literature reports. Both PL and LH kinetic models predict significantly different local MSR reaction rate and species partial pressure distributions along the normalized reactor length, indicating a strong need for further experimental verifications.

  15. 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.

  16. Focalised stimulation using high definition transcranial direct current stimulation (HD-tDCS) to investigate declarative verbal learning and memory functioning.

    Science.gov (United States)

    Nikolin, Stevan; Loo, Colleen K; Bai, Siwei; Dokos, Socrates; Martin, Donel M

    2015-08-15

    Declarative verbal learning and memory are known to be lateralised to the dominant hemisphere and to be subserved by a network of structures, including those located in frontal and temporal regions. These structures support critical components of verbal memory, including working memory, encoding, and retrieval. Their relative functional importance in facilitating declarative verbal learning and memory, however, remains unclear. To investigate the different functional roles of these structures in subserving declarative verbal learning and memory performance by applying a more focal form of transcranial direct current stimulation, "High Definition tDCS" (HD-tDCS). Additionally, we sought to examine HD-tDCS effects and electrical field intensity distributions using computer modelling. HD-tDCS was administered to the left dorsolateral prefrontal cortex (LDLPFC), planum temporale (PT), and left medial temporal lobe (LMTL) to stimulate the hippocampus, during learning on a declarative verbal memory task. Sixteen healthy participants completed a single blind, intra-individual cross-over, sham-controlled study which used a Latin Square experimental design. Cognitive effects on working memory and sustained attention were additionally examined. HD-tDCS to the LDLPFC significantly improved the rate of verbal learning (p=0.03, η(2)=0.29) and speed of responding during working memory performance (p=0.02, η(2)=0.35), but not accuracy (p=0.12, η(2)=0.16). No effect of tDCS on verbal learning, retention, or retrieval was found for stimulation targeted to the LMTL or the PT. Secondary analyses revealed that LMTL stimulation resulted in increased recency (p=0.02, η(2)=0.31) and reduced mid-list learning effects (p=0.01, η(2)=0.39), suggesting an inhibitory effect on learning. HD-tDCS to the LDLPFC facilitates the rate of verbal learning and improved efficiency of working memory may underlie performance effects. This focal method of administrating tDCS has potential for probing

  17. 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

  18. Direct mapping of ionic transport in a Si anode on the nanoscale: time domain electrochemical strain spectroscopy study.

    Science.gov (United States)

    Jesse, Stephen; Balke, Nina; Eliseev, Eugene; Tselev, Alexander; Dudney, Nancy J; Morozovska, Anna N; Kalinin, Sergei V

    2011-12-27

    Local Li-ion transport in amorphous silicon is studied on the nanometer scale using time domain electrochemical strain microscopy (ESM). A strong variability of ionic transport controlled by the anode surface morphology is observed. The observed relaxing and nonrelaxing response components are discussed in terms of local and global ionic transport mechanisms, thus establishing the signal formation mechanisms in ESM. This behavior is further correlated with local conductivity measurements. The implications of these studies for Si-anode batteries are discussed. The universal presence of concentration-strain coupling suggests that ESM and associated time and voltage spectroscopies can be applied to a broad range of electrochemical systems ranging from batteries to fuel cells.

  19. Anodic oxidation

    CERN Document Server

    Ross, Sidney D; Rudd, Eric J; Blomquist, Alfred T; Wasserman, Harry H

    2013-01-01

    Anodic Oxidation covers the application of the concept, principles, and methods of electrochemistry to organic reactions. This book is composed of two parts encompassing 12 chapters that consider the mechanism of anodic oxidation. Part I surveys the theory and methods of electrochemistry as applied to organic reactions. These parts also present the mathematical equations to describe the kinetics of electrode reactions using both polarographic and steady-state conditions. Part II examines the anodic oxidation of organic substrates by the functional group initially attacked. This part particular

  20. 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

    Directory of Open Access Journals (Sweden)

    Tiago da Silva Lopes

    2017-12-01

    Full Text Available 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

  1. 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.

  2. Layered oxygen-deficient double perovskite as an efficient and stable anode for direct hydrocarbon solid oxide fuel cells.

    Science.gov (United States)

    Sengodan, Sivaprakash; Choi, Sihyuk; Jun, Areum; Shin, Tae Ho; Ju, Young-Wan; Jeong, Hu Young; Shin, Jeeyoung; Irvine, John T S; Kim, Guntae

    2015-02-01

    Different layered perovskite-related oxides are known to exhibit important electronic, magnetic and electrochemical properties. Owing to their excellent mixed-ionic and electronic conductivity and fast oxygen kinetics, cation layered double perovskite oxides such as PrBaCo2O5 in particular have exhibited excellent properties as solid oxide fuel cell oxygen electrodes. Here, we show for the first time that related layered materials can be used as high-performance fuel electrodes. Good redox stability with tolerance to coking and sulphur contamination from hydrocarbon fuels is demonstrated for the layered perovskite anode PrBaMn2O5+δ (PBMO). The PBMO anode is fabricated by in situ annealing of Pr0.5Ba0.5MnO3-δ in fuel conditions and actual fuel cell operation is demonstrated. At 800 °C, layered PBMO shows high electrical conductivity of 8.16 S cm(-1) in 5% H2 and demonstrates peak power densities of 1.7 and 1.3 W cm(-2) at 850 °C using humidified hydrogen and propane fuels, respectively.

  3. Modelling and analysis of a direct methanol fuel cell with under-rib mass transport and two-phase flow at the anode

    Science.gov (United States)

    Yang, Yuming; Liang, Yung C.

    For the past decade, extensive mathematical modelling has been conducted on the design and optimization of liquid-feed direct methanol fuel cells (DMFCs). Detailed modelling of DMFC operations reveals that a two-phase flow phenomenon at the anode and under-rib convection due to the pressure difference between the adjacent channels both contribute significantly to mass-transfer in a DMFC and its output performance. In practice, comprehensive simulations based on the finite volume technique for two-phase flow require a high level of numerical complexity in computation. This study presents a complexity-reduced mathematical model that is developed to cover both phenomena for a realistic, but fast, in computation for the prediction and analysis of a DMFC prototype design. The simulation results are validated against experimental data with good agreement. Analysis of the DMFC mass-transfer is made to investigate methanol distribution at anode and its crossover through the proton-exchange membrane. From a comparison of the influence of two-phase flow and under-rib mass-transfer on DMFC performance, the significance of gas-phase methanol transport is established. Simulation results suggest that both the optimization of the flow-field structure and the fuel cell operating parameters (flow rate, methanol concentration and operating temperature) are important factors for competitive DMFC performance output.

  4. Improving the Energy Efficiency of Direct Formate Fuel Cells with a Pd/C-CeO2 Anode Catalyst and Anion Exchange Ionomer in the Catalyst Layer

    Directory of Open Access Journals (Sweden)

    Hamish Andrew Miller

    2018-02-01

    Full Text Available This article describes the development of a high power density Direct Formate Fuel Cell (DFFC fed with potassium formate (KCOOH. The membrane electrode assembly (MEA contains no platinum metal. The cathode catalyst is FeCo/C combined with a commercial anion exchange membrane (AEM. To enhance the power output and energy efficiency we have employed a nanostructured Pd/C-CeO2 anode catalyst. The activity for the formate oxidation reaction (FOR is enhanced when compared to a Pd/C catalyst with the same Pd loading. Fuel cell tests at 60 °C show a peak power density of almost 250 mW cm−2. The discharge energy (14 kJ, faradic efficiency (89% and energy efficiency (46% were determined for a single fuel charge (30 mL of 4 M KCOOH and 4 M KOH. Energy analysis demonstrates that removal of the expensive KOH electrolyte is essential for the future development of these devices. To compensate we apply for the first time a polymeric ionomer in the catalyst layer of the anode electrode. A homopolymer is synthesized by the radical polymerization of vinyl benzene chloride followed by amination with 1,4-diazabicyclo[2.2.2]octane (DABCO. The energy delivered, energy efficiency and fuel consumption efficiency of DFFCs fed with 4 M KCOOH are doubled with the use of the ionomer.

  5. Enhance performance of micro direct methanol fuel cell by in situ CO2 removal using novel anode flow field with superhydrophobic degassing channels

    Science.gov (United States)

    Liang, Junsheng; Luo, Ying; Zheng, Sheng; Wang, Dazhi

    2017-05-01

    Capillary blocking caused by CO2 bubbles in anode flow field (AFF) is one of the bottlenecks for performance improvement of a micro direct methanol fuel cell (μDMFC). In this work, we present a novel AFF structure with nested layout of hydrophilic fuel channels and superhydrophobic degassing channels which can remove most of CO2 from AFF before it is released to the fuel channels. The new AFFs are fabricated on Ti substrates by using micro photochemical etching combined with anodization and fluorination treatments. Performance of the μDMFCs with and without superhydrophobic degassing channels in their AFF is comparatively studied. Results show that the superhydrophobic degassing channels can significantly speed up the exhaust of CO2 from the AFF. CO2 clogging is not observed in the new AFFs even when their comparison AFFs have been seriously blocked by CO2 slugs under the same operating conditions. 55% and 60% of total CO2 produced in μDMFCs with N-serpentine and N-spiral AFF can be respectively removed by the superhydrophobic degassing channels. The power densities of the μDMFCs equipped with new serpentine and spiral AFFs are respectively improved by 30% and 90% compared with those using conventional AFFs. This means that the new AFFs developed in this work can effectively prevent CO2-induced capillary blocking in the fuel channels, and finally significantly improve the performance of the μDMFCs.

  6. Pd-Pt loaded graphene aerogel on nickel foam composite as binder-free anode for a direct glucose fuel cell unit

    Science.gov (United States)

    Tsang, Chi Him A.; Leung, D. Y. C.

    2017-09-01

    Fabrication of electrocatalyst for direct glucose fuel cell (DGFC) operation involves destructive preparation methods with the use of stabilizer like binder, which may cause activity depreciation. Binder-free electrocatalytic electrode becomes a possible solution to the above problem. Binder-free bimetallic Pd-Pt loaded graphene aerogel on nickel foam plates with different Pd/Pt ratios (1:2.32, 1:1.62, and 1:0.98) are successfully fabricated through a green one-step mild reduction process producing a Pd-Pt/GO/nickel form plate (NFP) composite. Anode with the binder-free electrocatalysts exhibit a strong activity in a batch type DGFC unit under room temperature. The effects of glucose and KOH concentrations, and the Pd/Pt ratios of the electrocatalyst on the DGFC performance are also studied. Maximum power density output of 1.25 mW cm-2 is recorded with 0.5 M glucose/3 M KOH as the anodic fuel, and Pd1Pt0.98/GA/NFP as catalyst, which is the highest obtained so far among other types of electrocatalyst.

  7. Transcranial Current Stimulation of the Temporoparietal Junction Improves Lie Detection.

    Science.gov (United States)

    Sowden, Sophie; Wright, Gordon R T; Banissy, Michael J; Catmur, Caroline; Bird, Geoffrey

    2015-09-21

    The ability to detect deception is of vital importance in human society, playing a crucial role in communication, cooperation, and trade between societies, businesses, and individuals. However, numerous studies have shown, remarkably consistently, that we are only slightly above chance when it comes to detecting deception. Here we investigate whether inconsistency between one's own opinion and the stated opinion of another impairs judgment of the veracity of that statement, in the same way that one's own mental, affective, and action states, when inconsistent, can interfere with representation of those states in another. Within the context of lie detection, individuals may be less accurate when judging the veracity of another's opinion when it is inconsistent with their own opinion. Here we present a video-mediated lie-detection task to confirm this prediction: individuals correctly identified truths or lies less often when the other's expressed opinion was inconsistent with their own (experiment 1). Transcranial direct current stimulation (tDCS) of the temporoparietal junction (TPJ) has previously been shown to improve the ability to selectively represent the self or another. We therefore predicted that TPJ stimulation would enable lie detectors to inhibit their own views, enhance those of the other, and improve their ability to determine whether another was presenting their true opinion. Experiment 2 confirmed this second prediction: anodal tDCS of the TPJ improved lie detection specifically when one's own and others' views were conflicting. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Investigation of B-site doped perovskites Sr2Fe1.4X0.1Mo0.5O6-δ (X=Bi, Al, Mg) as high-performance anodes for hybrid direct carbon fuel cell

    Science.gov (United States)

    Sun, Kening; Liu, Jia; Feng, Jie; Yuan, Hong; He, Minjie; Xu, Chunming; Wang, Zhenhua; Sun, Wang; Qiao, Jinshuo

    2017-10-01

    B-site substituted Sr2Fe1.4X0.1Mo0.5O6-δ (SFXM, X = Bi, Al and Mg) are evaluated as anode materials for hybrid direct carbon fuel cells (HDCFCs). The structure, morphology, conductivity and catalytic activity of the as-prepared SFXM anode are systematically investigated. Under a reducing atmosphere, the exsolution of metallic Fe from the SFXM perovskite lattice are demonstrated by the XRD, SEM and TEM observations. Further element valence analysis on reduced SFXM suggests the X doping significantly alters the Fe3+/Fe2+ and Mo6+/Mo5+ ratio, and thus beneficial to the intrinsic conductivity of SFXM. All these advantages are responsible for the good electrochemical performances of SFXM anodes. Meanwhile, among these SFXM anodes, the conductivity, catalytic activity and electrochemical performance all obey the order of SFBM > SFAM > SFMM. The maximum power densities of the La0.8Sr0.2Ga0.8Mg0.2O3 electrolyte supported single cell with SFBM as the anode reaches 399, 287 and 141 mW cm-2 at 800 °C, 750 °C and 700 °C, respectively. Such designed B-site substitution perovskites have great potential to be applied as HDCFC anode materials.

  9. Anodal tDCS over the Primary Motor Cortex Facilitates Long-Term Memory Formation Reflecting Use-Dependent Plasticity.

    Directory of Open Access Journals (Sweden)

    Orjon Rroji

    Full Text Available Previous research suggests that anodal transcranial direct current stimulation (tDCS over the primary motor cortex (M1 modulates NMDA receptor dependent processes that mediate synaptic plasticity. Here we test this proposal by applying anodal versus sham tDCS while subjects practiced to flex the thumb as fast as possible (ballistic movements. Repetitive practice of this task has been shown to result in performance improvements that reflect use-dependent plasticity resulting from NMDA receptor mediated, long-term potentiation (LTP-like processes. Using a double-blind within-subject cross-over design, subjects (n=14 participated either in an anodal or a sham tDCS session which were at least 3 months apart. Sham or anodal tDCS (1 mA was applied for 20 min during motor practice and retention was tested 30 min, 24 hours and one week later. All subjects improved performance during each of the two sessions (p < 0.001 and learning gains were similar. Our main result is that long term retention performance (i.e. 1 week after practice was significantly better when practice was performed with anodal tDCS than with sham tDCS (p < 0.001. This effect was large (Cohen's d=1.01 and all but one subject followed the group trend. Our data strongly suggest that anodal tDCS facilitates long-term memory formation reflecting use-dependent plasticity. Our results support the notion that anodal tDCS facilitates synaptic plasticity mediated by an LTP-like mechanism, which is in accordance with previous research.

  10. Photoactive layered nanocomposites obtained by direct transferring of anodic TiO{sub 2} nanotubes to commodity thermoplastics

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, Ruy, E-mail: ruy.sanzgonzalez@cnr.it [CNR-IMM, Via Santa Sofia 64, I-95123 Catania (Italy); Buccheri, Maria Antonietta; Zimbone, Massimo; Scuderi, Viviana; Amiard, Guillaume; Impellizzeri, Giuliana [CNR-IMM, Via Santa Sofia 64, I-95123 Catania (Italy); Romano, Lucia [CNR-IMM, Via Santa Sofia 64, I-95123 Catania (Italy); Department of Physics, University of Catania, Via Santa Sofia 64, I-95123 Catania (Italy); Privitera, Vittorio [CNR-IMM, Via Santa Sofia 64, I-95123 Catania (Italy)

    2017-03-31

    Highlights: • Rapid and scalable synthesis of flexible photoactive layered nanocomposites is presented. • The nanocomposites show similar photonic efficiencies to TiO{sub 2} nanotubes and commercial products. • The nanocomposites exhibit antibacterial properties under 1 mW cm{sup −2} UVA. • The synthesis process is solvent-free and reduces the amount of raw materials. - Abstract: TiO{sub 2} nanotubes demonstrated to be a versatile nanostructure for biomaterials, clean energy and water remediation applications. However, the cost of titanium and the poor mechanical properties of the nanotubes hinder their adoption at large scale. This work presents a straightforward and scalable method for transferring photoactive anodic TiO{sub 2} nanotubes from titanium foils to commodity thermoplastic polymers, polypropylene, polyethylene terephthalate, polycarbonate, and polymethylmetacrylate, allowing the reusing of the remaining titanium. The obtained flexible nanocomposites reach a maximum photonic efficiencies of 0.038% (ISO-10678:2010) representing the 93% of photonic efficiency of TiO{sub 2} nanotubes on titanium. In addition, the nanocomposites and TiO{sub 2} nanotubes on titanium present similar antibacterial properties under 1 mW cm{sup −2} UV-A, 60% of Escherichia coli survival after 1 h of exposition. The final objective of this work is to point out main concepts and key parameters for a low-cost fabrication of a photoactive nanocomposite material.

  11. Estimulação transcraniana por corrente direta: uma alternativa promissora para o tratamento da depressão maior? Transcranial direct current stimulation: a promising alternative for the treatment of major depression?

    Directory of Open Access Journals (Sweden)

    Marcelo T. Berlim

    2009-05-01

    esclarecer seu real papel no manejo dos transtornos depressivos.OBJECTIVE: In recent years, a number of new somatic (non-pharmacological treatments have been developed for the treatment of major depression and other neuropsychiatric disorders. Among these, one of the most promising is transcranial direct current stimulation. Method: For the present literature review we searched the PubMed between January 1985 and February 2009. To be included, articles should have been published in English and should address general principles of transcranial direct current stimulation and its use in major depression. DISCUSSION: Current protocols for the treatment of major depression with transcranial direct current stimulation usually involve the application of two sponge-electrodes in the scalp. In general, the positive electrode is applied in the region above the left dorsolateral prefrontal cortex (i.e., F3 region of the 10/20 International System for EEG and the negative electrode is applied in the region above the right supra-orbital area. A direct electrical current of 1-2 mA is then applied between the electrodes for about 20 minutes, with sessions being daily performed for one to two weeks. Initial studies (including a randomized, double-blind, placebo-controlled clinical trial showed that transcranial direct current stimulation is effective for the treatment of non-complicated major depression and that this technique, when used in depressed patients, is associated with improvement in cognitive performance (including working memory. Finally, transcranial direct current stimulation is safe and well tolerated. CONCLUSION: Recent studies show that transcranial direct current stimulation is an important neuromodulatory method that may be useful for the treatment of depressed patients. However, further studies are needed to better clarify its precise role in the management of depressive disorders.

  12. Electrochemical and catalytic properties of Ni/BaCe0.75Y0.25O3-δ anode for direct ammonia-fueled solid oxide fuel cells.

    Science.gov (United States)

    Yang, Jun; Molouk, Ahmed Fathi Salem; Okanishi, Takeou; Muroyama, Hiroki; Matsui, Toshiaki; Eguchi, Koichi

    2015-04-08

    In this study, Ni/BaCe0.75Y0.25O3-δ (Ni/BCY25) was investigated as an anode for direct ammonia-fueled solid oxide fuel cells. The catalytic activity of Ni/BCY25 for ammonia decomposition was found to be remarkably higher than Ni/8 mol % Y2O3-ZrO2 and Ni/Ce0.90Gd0.10O1.95. The poisoning effect of water and hydrogen on ammonia decomposition reaction over Ni/BCY25 was evaluated. In addition, an electrolyte-supported SOFC employing BaCe0.90Y0.10O3-δ (BCY10) electrolyte and Ni/BCY25 anode was fabricated, and its electrochemical performance was investigated at 550-650 °C with supply of ammonia and hydrogen fuel gases. The effect of water content in anode gas on the cell performance was also studied. Based on these results, it was concluded that Ni/BCY25 was a promising anode for direct ammonia-fueled SOFCs. An anode-supported single cell denoted as Ni/BCY25|BCY10|Sm0.5Sr0.5CoO3-δ was also fabricated, and maximum powder density of 216 and 165 mW cm(-2) was achieved at 650 and 600 °C, for ammonia fuel, respectively.

  13. Point-of-care-testing of standing posture with Wii balance board and Microsoft Kinect during transcranial direct current stimulation: a feasibility study.

    Science.gov (United States)

    Dutta, Arindam; Chugh, Sanjay; Banerjee, Alakananda; Dutta, Anirban

    2014-01-01

    Non-invasive brain stimulation (NIBS) is a promising tool for facilitating motor function. NIBS therapy in conjunction with training using postural feedback may facilitate physical rehabilitation following posture disorders (e.g., Pusher Syndrome). The objectives of this study were, 1) to develop a low-cost point-of-care-testing (POCT) system for standing posture, 2) to investigate the effects of anodal tDCS on functional reach tasks using the POCT system. Ten community-dwelling elderly (age >50 years) subjects evaluated the POCT system for standing posture during functional reach tasks where their balance score on Berg Balance Scale was compared with that from Center-of-Mass (CoM) - Center-of-Pressure (CoP) posturography. Then, in a single-blind, sham-controlled study, five healthy right-leg dominant subjects (age: 26.4 ± 5.3 yrs) were evaluated using the POCT system under two conditions - with anodal tDCS of primary motor representations of right tibialis anterior muscle and with sham tDCS. The maximum CoP-CoM lean-angle was found to be well correlated with the BBS score in the elderly subjects The anodal tDCS strongly (p = 0.0000) affected the maximum CoP excursions but not the return reaction time in healthy. It was concluded that the CoM-CoP lean-line could be used for posture feedback and monitoring during tDCS therapy in conjunction with balance training exercises.

  14. Reduction of carbon dioxide gas formation at the anode of a direct methanol fuel cell using chemically enhanced solubility

    Science.gov (United States)

    Lundin, Michael D.; McCready, Mark J.

    The production of CO 2 gas at the DMFC anode leads to dramatic increases in pumping power requirements and reduced power output because of mass transfer limitations as bubble trains form in the channels of larger stacks. Experimental observations taken in a 5 cm 2 DMFC test cell operated at 60 °C, 1 atm, and with a methanol/water fuel flow rates of 5-10 cm 3 min -1 indicate that the rate of bubble formation can be reduced by increasing the fuel flow because more liquid is available for the CO 2 to dissolve in. Further observations indicate that KOH and LiOH added to the fuel eliminates CO 2 gas formation in situ at low concentrations because of the greatly increased solubility that results. A mathematical model for the volumetric rate of CO 2 gas production that includes effects of temperature and solubility is developed and extended to include the effects of hydroxide ions in solution. The model is used to predict the onset location of gas formation in the flow field as well as the void fraction at any point in the flow field. Predictions from the model agree very well with our experiments. Model predictions explain differences in the initial location of bubble formation for fuel solutions pre-saturated with CO 2 as opposed to CO 2-free solutions. Experiments with KOH and LiOH added to fuel solutions confirm the validity of the model extension that includes solubility that is enhanced by chemical reaction. Experiments with LiOH, KOH, and ammonium hydroxide show that the long-term durability of standard Pt-Ru/Nafion ®/Pt membrane electrode assemblies is compromised because of the presence of lithium, potassium, and ammonium cations that interact with the Nafion ® membrane and result in increasing the ohmic limitations of the polymer electrolyte membrane. Experiments with Ca(OH) 2, while reducing gas formation, precipitate the product CaCO 3 out of solution too rapidly for downstream filtering, blocking channels in the flow field.

  15. The Short-Term Effects of Transcranial Direct Current Stimulation on Electroencephalography in Children with Autism: A Randomized Crossover Controlled Trial

    Directory of Open Access Journals (Sweden)

    Anuwat Amatachaya

    2015-01-01

    Full Text Available Abnormal synaptic maturation and connectivity are possible etiologies of autism. Previous studies showed significantly less alpha activity in autism than normal children. Therefore, we studied the effects of anodal tDCS on peak alpha frequency (PAF related to autism treatment evaluation checklist (ATEC. Twenty male children with autism were randomly assigned in a crossover design to receive a single session of both active and sham tDCS stimulation (11 mA over F3 (left dorsolateral prefrontal cortex. Pre- to postsession changes in a measure of cortical activity impacted by tDCS (PAF and ATEC were compared between groups. We also examined the associations between pre- and postsession changes in the PAF and ATEC. The results show significant pre- to postsession improvements in two domains of ATEC (social and health/behavior domains following active tDCS, relative to sham treatment. PAF also significantly increased at the stimulation site, and an increase in PAF was significantly associated with improvements in the two domains of ATEC impacted by tDCS. The findings suggest that a single session of anodal tDCS over the F3 may have clinical benefits in children with autism and that those benefits may be related to an increase in PAF.

  16. Anodal tDCS applied during multitasking training leads to transferable performance gains.

    Science.gov (United States)

    Filmer, Hannah L; Lyons, Maxwell; Mattingley, Jason B; Dux, Paul E

    2017-10-11

    Cognitive training can lead to performance improvements that are specific to the tasks trained. Recent research has suggested that transcranial direct current stimulation (tDCS) applied during training of a simple response-selection paradigm can broaden performance benefits to an untrained task. Here we assessed the impact of combined tDCS and training on multitasking, stimulus-response mapping specificity, response-inhibition, and spatial attention performance in a cohort of healthy adults. Participants trained over four days with concurrent tDCS - anodal, cathodal, or sham - applied to the left prefrontal cortex. Immediately prior to, 1 day after, and 2 weeks after training, performance was assessed on the trained multitasking paradigm, an untrained multitasking paradigm, a go/no-go inhibition task, and a visual search task. Training combined with anodal tDCS, compared with training plus cathodal or sham stimulation, enhanced performance for the untrained multitasking paradigm and visual search tasks. By contrast, there were no training benefits for the go/no-go task. Our findings demonstrate that anodal tDCS combined with multitasking training can extend to untrained multitasking paradigms as well as spatial attention, but with no extension to the domain of response inhibition.

  17. Enhanced activity of Pt/CNTs anode catalyst for direct methanol fuel cells using Ni2P as co-catalyst

    Science.gov (United States)

    Li, Xiang; Luo, Lanping; Peng, Feng; Wang, Hongjuan; Yu, Hao

    2018-03-01

    The direct methanol fuel cell is a promising energy conversion device because of the utilization of the state-of-the-art platinum (Pt) anode catalyst. In this work, novel Pt/Ni2P/CNTs catalysts were prepared by the H2 reduction method. It was found that the activity and stability of Pt for methanol oxidation reaction (MOR) could be significantly enhanced while using nickel phosphide (Ni2P) nanoparticles as co-catalyst. X-ray photoelectron spectroscopy revealed that the existence of Ni2P affected the particle size and electronic distribution of Pt obviously. Pt/CNTs catalyst, Pt/Ni2P/CNTs catalysts with different Ni2P amount were synthesized, among which Pt/6%Ni2P/CNTs catalyst exhibited the best MOR activity of 1400 mAmg-1Pt, which was almost 2.5 times of the commercial Pt/C-JM catalyst. Moreover, compared to other Pt-based catalysts, this novel Pt/Ni2P/CNTs catalyst also exhibited higher onset current density and better steady current density. The result of this work may provide positive guidance to the research on high efficiency and stability of Pt-based catalyst for direct methanol fuel cells.

  18. Fabrication and Characterization of New Composite Tio2Carbon Nanofiber Anodic Catalyst Support for Direct Methanol Fuel Cell via Electrospinning Method.

    Science.gov (United States)

    Abdullah, N; Kamarudin, S K; Shyuan, L K; Karim, N A

    2017-12-06

    Platinum (Pt) is the common catalyst used in a direct methanol fuel cell (DMFC). However, Pt can lead towards catalyst poisoning by carbonaceous species, thus reduces the performance of DMFC. Thus, this study focuses on the fabrication of a new composite TiO 2 carbon nanofiber anodic catalyst support for direct methanol fuel cells (DMFCs) via electrospinning technique. The distance between the tip and the collector (DTC) and the flow rate were examined as influencing parameters in the electrospinning technique. To ensure that the best catalytic material is fabricated, the nanofiber underwent several characterizations and electrochemical tests, including FTIR, XRD, FESEM, TEM, and cyclic voltammetry. The results show that D18, fabricated with a flow rate of 0.1 mLhr -1 and DTC of 18 cm, is an ultrafine nanofiber with the smallest average diameter, 136.73 ± 39.56 nm. It presented the highest catalyst activity and electrochemical active surface area value as 274.72 mAmg -1 and 226.75m 2  g -1 PtRu , respectively, compared with the other samples.

  19. Fabrication and Characterization of New Composite Tio2 Carbon Nanofiber Anodic Catalyst Support for Direct Methanol Fuel Cell via Electrospinning Method

    Science.gov (United States)

    Abdullah, N.; Kamarudin, S. K.; Shyuan, L. K.; Karim, N. A.

    2017-12-01

    Platinum (Pt) is the common catalyst used in a direct methanol fuel cell (DMFC). However, Pt can lead towards catalyst poisoning by carbonaceous species, thus reduces the performance of DMFC. Thus, this study focuses on the fabrication of a new composite TiO2 carbon nanofiber anodic catalyst support for direct methanol fuel cells (DMFCs) via electrospinning technique. The distance between the tip and the collector (DTC) and the flow rate were examined as influencing parameters in the electrospinning technique. To ensure that the best catalytic material is fabricated, the nanofiber underwent several characterizations and electrochemical tests, including FTIR, XRD, FESEM, TEM, and cyclic voltammetry. The results show that D18, fabricated with a flow rate of 0.1 mLhr-1 and DTC of 18 cm, is an ultrafine nanofiber with the smallest average diameter, 136.73 ± 39.56 nm. It presented the highest catalyst activity and electrochemical active surface area value as 274.72 mAmg-1 and 226.75m2 g-1 PtRu, respectively, compared with the other samples.

  20. Does transcranial electrical stimulation enhance corticospinal excitability of the motor cortex in healthy individuals? A systematic review and meta-analysis.

    Science.gov (United States)

    Dissanayaka, Thusharika; Zoghi, Maryam; Farrell, Michael; Egan, Gary F; Jaberzadeh, Shapour

    2017-08-01

    Numerous studies have explored the effects of transcranial electrical stimulation (tES) - including anodal transcranial direct current stimulation (a-tDCS), cathodal transcranial direct current stimulation (c-tDCS), transcranial alternative current stimulation (tACS), transcranial random noise stimulation (tRNS) and transcranial pulsed current stimulation (tPCS) - on corticospinal excitability (CSE) in healthy populations. However, the efficacy of these techniques and their optimal parameters for producing robust results has not been studied. Thus, the aim of this systematic review was to consolidate current knowledge about the effects of various parameters of a-tDCS, c-tDCS, tACS, tRNS and tPCS on the CSE of the primary motor cortex (M1) in healthy people. Leading electronic databases were searched for relevant studies published between January 1990 and February 2017; 126 articles were identified, and their results were extracted and analysed using RevMan software. The meta-analysis showed that a-tDCS application on the dominant side significantly increases CSE (P < 0.01) and that the efficacy of a-tDCS is dependent on current density and duration of application. Similar results were obtained for stimulation of M1 on the non-dominant side (P = 0.003). The effects of a-tDCS reduce significantly after 24 h (P = 0.006). Meta-analysis also revealed significant reduction in CSE following c-tDCS (P < 0.001) and significant increases after tRNS (P = 0.03) and tPCS (P = 0.01). However, tACS effects on CSE were only significant when the stimulation frequency was ≥140 Hz. This review provides evidence that tES has substantial effects on CSE in healthy individuals for a range of stimulus parameters. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  1. 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.

  2. Transient Response and Steady-State Analysis of the Anode of Direct Methanol Fuel Cells Based on Dual-Site Kinetics

    Directory of Open Access Journals (Sweden)

    Lei Xing

    2011-01-01

    Full Text Available An intrinsic time-dependent one-dimensional (1D model and a macro two-dimensional (2D model for the anode of the direct methanol fuel cell (DMFC are presented. The two models are based on the dual-site mechanism, which includes the coverage of intermediate species of methanol, OH, and CO (θM, θOH,Ru, and θCO,Pt on the surface of Pt and Ru. The intrinsic 1D model focused on the analysis of the effects of operating temperature, methanol concentration, and overpotential on the transient response. The macro 2D model emphasises the dimensionless distributions of methanol concentration, overpotential and current density in the catalyst layer which were affected by physical parameters such as thickness, specific area, and operating conditions such as temperature, bulk methanol concentration, and overpotential. The models were developed and solved in the PDEs module of COMSOL Multiphysics, giving good agreement with experimental data. The dimensionless distributions of methanol concentration, overpotential, and current density and the efficiency factor were calculated quantitatively. The models can be used to give accurate simulations for the polarisations of methanol fuel cell.

  3. Fluorescence-based high throughput screening for noble metal-free and platinum-poor anode catalysts for the direct methanol fuel cell.

    Science.gov (United States)

    Welsch, F G; Stöwe, K; Maier, W F

    2011-09-12

    We describe here the results of a high throughput screening study for direct methanol fuel cell (DMFC) anode catalysts consisting of new elemental combinations with an optical high-throughput screening method, which allows the quantitative evaluation of the electrochemical activity of catalysts. The method is based on the fluorescence of protonated quinine generated during electrooxidation of methanol. The high-throughput screening included noble-metal free binary and ternary mixed oxides of the elements Al, Co, Cr, Cu, Fe, Mn, Mo, Nb, Ni, Ta, Ti, Zn, and Zr in the oxidized form as well as after prior reduction in hydrogen. In addition 318 ternary and quaternary Pt-containing materials composed out of the mixed oxides of Bi, Ce, Co, Cr, Cu, Fe, Ga, Ge, In, La, Mn, Mo, Nb, Nd, Ni, Pr, Sb, Sn, Ta, Te, Ti, V, Zn, and Zr with a molar Pt-ratio of 10% and 30% were screened. Validation and long time experiments of the hits were performed by cyclovoltammetry (CV). The microstructural stability of the electrode preparations of the lead compositions was studied by X-ray diffraction (XRD) pattern analysis.

  4. Effect of the Pd/MWCNTs anode catalysts preparation methods on their morphology and activity in a direct formic acid fuel cell

    Science.gov (United States)

    Lesiak, B.; Mazurkiewicz, M.; Malolepszy, A.; Stobinski, L.; Mierzwa, B.; Mikolajczuk-Zychora, A.; Juchniewicz, K.; Borodzinski, A.; Zemek, J.; Jiricek, P.

    2016-11-01

    Impact of Pd/MWCNTs catalysts preparation method on the catalysts morphology and activity in a formic acid electrooxidation reaction was investigated. Three reduction methods of Pd precursor involving reduction in a high pressure microwave reactor (Pd1), reduction with NaBH4 (Pd2) and microwave-assisted polyol method (Pd3) were used in this paper. Crystallites size and morphology were studied using the scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), whereas elemental composition, Pd chemical state and functional groups content by the X-ray photoelectron spectroscopy (XPS). The prepared catalysts were tested in a direct formic acid fuel cell (DFAFC) as an anode material. The catalytic activity was correlated with a mean fraction of the total Pd atoms exposed at the surface (FE). The value of FE was calculated from the crystallites size distribution determined by the STEM measurements. Non-linear dependence of a current density versus FE, approaching the maximum at FE≈0.25 suggests that the catalytic process proceeded at Pd nanocrystallites faces, with inactive edges and corners. Pd2 catalyst exhibited highest activity due to its smallest Pd crystallites (3.2 nm), however the absence of Pd crystallites aggregation and low content of carbon in PdCx phase, i.e. x = 4 at.% may also affect the observed.

  5. Controlled synthesis of Pt/CS/PW{sub 12}-GNs composite as an anodic electrocatalyst for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhongshui; Lei, Fengling; Ye, Lingting; Zhang, Xiaofeng; Lin, Shen, E-mail: shenlin@fjnu.edu.cn [Fujian Normal University, College of Chemistry & Chemical Engineering (China)

    2015-04-15

    Controlled assembly in aqueous solution was used to synthesize the well-organized Pt/CS/PW{sub 12}-GNs composite. By the aid of linear cationic polysaccharide chitosan, 2-D distribution worm-like Pt nanoparticles with their length and width of 15–20 and 3–4 nm, respectively, were formed on the surface of CS/PW{sub 12}-GNs using HCOOH as a reducing agent at room temperature. The introduction of CS leads to well dispersion of worm-like Pt nanoparticles, the electroactivity of H{sub 3}PW{sub 12}O{sub 40} (PW{sub 12}) alleviates CO poisoning toward Pt particles, and graphene nanosheets (GNs) ensure excellent electrical conductivity of the composites. The combined action among different components results in significantly enhanced catalytic activity of Pt/CS/PW{sub 12}-GNs toward methanol oxidation and better tolerance of CO. The as-synthesized Pt/CS/PW{sub 12}-GNs exhibit the forward peak current density of 445 mA mg{sup −1}, which is much higher than that (220 mA mg{sup −1}) for Pt/C-JM (the commercially available Johnson Matthey Hispec4000 catalyst, simplified as Pt/C-JM) and some recently reported Pt/graphene-based nanomaterials. The construction of 2-D distribution worm-like Pt nanoparticles and facile wet chemical synthesis strategy provide a promising way to develop superior performance electrocatalysts for direct methanol fuel cells applications.

  6. Effect of the Pd/MWCNTs anode catalysts preparation methods on their morphology and activity in a direct formic acid fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Lesiak, B., E-mail: blesiak-orlowska@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa (Poland); Mazurkiewicz, M.; Malolepszy, A. [Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645 Warszawa (Poland); Stobinski, L. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa (Poland); Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645 Warszawa (Poland); Mierzwa, B.; Mikolajczuk-Zychora, A.; Juchniewicz, K.; Borodzinski, A. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa (Poland); Zemek, J.; Jiricek, P. [Institute of Physics, Academy of Sciences of the Czech Republic, 162-53 Prague 6, Cukrovarnicka 10 (Czech Republic)

    2016-11-30

    Highlights: • Catalysts properties studied by XRD, STEM, XPS methods. • Differences in Pd particle size, content of Pd, functional groups, PdC{sub x.}. • Catalytic activity studied in a Direct Formic Acid Fuel Cell. • Highest activity–catalyst prepared using a strong reducing agent (NaBH{sub 4}). - Abstract: Impact of Pd/MWCNTs catalysts preparation method on the catalysts morphology and activity in a formic acid electrooxidation reaction was investigated. Three reduction methods of Pd precursor involving reduction in a high pressure microwave reactor (Pd1), reduction with NaBH{sub 4} (Pd2) and microwave-assisted polyol method (Pd3) were used in this paper. Crystallites size and morphology were studied using the scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), whereas elemental composition, Pd chemical state and functional groups content by the X-ray photoelectron spectroscopy (XPS). The prepared catalysts were tested in a direct formic acid fuel cell (DFAFC) as an anode material. The catalytic activity was correlated with a mean fraction of the total Pd atoms exposed at the surface (FE). The value of FE was calculated from the crystallites size distribution determined by the STEM measurements. Non-linear dependence of a current density versus FE, approaching the maximum at FE≈0.25 suggests that the catalytic process proceeded at Pd nanocrystallites faces, with inactive edges and corners. Pd2 catalyst exhibited highest activity due to its smallest Pd crystallites (3.2 nm), however the absence of Pd crystallites aggregation and low content of carbon in PdC{sub x} phase, i.e. x = 4 at.% may also affect the observed.

  7. Effects of microstructure and composition of anode Pt based electrocatalysts on performance of direct alcohol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, L.; Li, H.; Yan, S.; Sun, G. [Dalian Inst. of Chemical Physics, Dalian (China). Direct Alcohol Fuel Cell Lab; Xin, Q. [Dalian Inst. of Chemical Physics, Dalian (China). Direct Alcohol Fuel Cell Lab; Dalian Inst. of Chemical Physics, Dalian (China). State Key Laboratory of Catalysis

    2008-07-01

    This paper reported on a study in which platinum (Pt)-based electrocatalysts were synthesized and characterized by XRD, TEM and EDS. The focus of the study was on the relationship between the microstructure and components of PtRu and PtSn catalysts and the performance of direct alcohol fuel cells (DAFCs). All of the Pt-based electrocatalysts were prepared by a modified polyol method. XRD patterns of the 2 catalysts showed that both catalysts have an fcc pattern of Pt. This was also confirmed by the shift of diffraction peaks of Pt in both catalysts. Electrochemical measurements were carried out using an EG and G model 273A potentiostat/galvanostat and a three-electrode test cell at room temperature. Membrane electrode assemblies (MEAs) were fabricated with a pair of stainless steel plates with parallel flow-fields. The MEAs were activated by 1 M methanol/ethanol at 75 degrees C for 3 hours before all the data were collected. The study showed that PtRu is active to methanol electrooxidation while PtSn is active to ethanol electrooxidation. Based on the above experimental analysis, it was determined that the dilatation of Pt lattice parameter is favourable for ethanol adsorption, while the suitable contract of Pt lattice parameter is favorable for methanol electrooxidation. Since Pt is more electronegative than Sn, the partial electrons of Sn atom could be transferred to Pt atom leading to filling of Pt d band. Although Ru is as electronegative as Pt, the electric effect of Pt and Ru may not be as pronounced. 4 refs., 4 figs.

  8. Transcranial sound field characterization.

    Science.gov (United States)

    Hölscher, Thilo; Wilkening, Wilko G; Molkenstruck, Sven; Voit, Heinz; Koch, Christian

    2008-06-01

    In the scope of therapeutic ultrasound applications in the adult brain, such as sonothrombolysis in stroke, a better understanding of the intracranial acoustic properties during insonation through the temporal bone is warranted. Innovative ultrasound imaging techniques, like transcranial duplex sonography, may open new avenues to apply ultrasound for therapeutic purposes and to visually monitor the effect using the same device. The aim was to study the transcranial sound field aberrations and the changes of acoustic parameters, using a high-end duplex machine. Six cadaver skulls were insonated through the temporal bone window, using a diagnostic duplex ultrasound device. The measurements were done in a water tank, using a needle hydrophone to assess and compute acoustic parameters, such as peak intensity, peak-to-peak, peak-positive, peak-negative acoustic pressure, beam area etc. in a 2-D plane. It could be shown that the absorption and wavefront distortion effects of the temporal bone are variable among different skulls. Because of signal absorption of the bone, the mechanical index of the incident ultrasound wave drops by a factor > or =10 in most cases. However, the beam area might be increased by a factor of almost 4, because of phase aberration (i.e., defocusing). (

  9. Combined Transcranial Direct Current Stimulation and Virtual Reality-Based Paradigm for Upper Limb Rehabilitation in Individuals with Restricted Movements. A Feasibility Study with a Chronic Stroke Survivor with Severe Hemiparesis.

    Science.gov (United States)

    Fuentes, María Antonia; Borrego, Adrián; Latorre, Jorge; Colomer, Carolina; Alcañiz, Mariano; Sánchez-Ledesma, María José; Noé, Enrique; Llorens, Roberto

    2018-04-02

    Impairments of the upper limb function are a major cause of disability and rehabilitation. Most of the available therapeutic options are based on active exercises and on motor and attentional inclusion of the affected arm in task oriented movements. However, active movements may not be possible after severe impairment of the upper limbs. Different techniques, such as mirror therapy, motor imagery, and non-invasive brain stimulation have been shown to elicit cortical activity in absence of movements, which could be used to preserve the available neural circuits and promote motor learning. We present a virtual reality-based paradigm for upper limb rehabilitation that allows for interaction of individuals with restricted movements from active responses triggered when they attempt to perform a movement. The experimental system also provides multisensory stimulation in the visual, auditory, and tactile channels, and transcranial direct current stimulation coherent to the observed movements. A feasibility study with a chronic stroke survivor with severe hemiparesis who seemed to reach a rehabilitation plateau after two years of its inclusion in a physical therapy program showed clinically meaningful improvement of the upper limb function after the experimental intervention and maintenance of gains in both the body function and activity. The experimental intervention also was reported to be usable and motivating. Although very preliminary, these results could highlight the potential of this intervention to promote functional recovery in severe impairments of the upper limb.

  10. Physiological and modeling evidence for focal transcranial electrical brain stimulation in humans: A basis for high-definition tDCS

    Science.gov (United States)

    Edwards, Dylan; Cortes, Mar; Datta, Abhishek; Minhas, Preet; Wassermann, Eric M.; Bikson, Marom

    2015-01-01

    Transcranial Direct Current Stimulation (tDCS) is a non-invasive, low-cost, well-tolerated technique producing lasting modulation of cortical excitability. Behavioral and therapeutic outcomes of tDCS are linked to the targeted brain regions, but there is little evidence that current reaches the brain as intended. We aimed to: (1) validate a computational model for estimating cortical electric fields in human transcranial stimulation, and (2) assess the magnitude and spread of cortical electric field with a novel High-Definition tDCS (HD-tDCS) scalp montage using a 4×1-Ring electrode configuration. In three healthy adults, Transcranial Electrical Stimulation (TES) over primary motor cortex (M1) was delivered using the 4×1 montage (4× cathode, surrounding a single central anode; montage radius ~3 cm) with sufficient intensity to elicit a discrete muscle twitch in the hand. The estimated current distribution in M1 was calculated using the individualized MRI-based model, and compared with the observed motor response across subjects. The response magnitude was quantified with stimulation over motor cortex as well as anterior and posterior to motor cortex. In each case the model data were consistent with the motor response across subjects. The estimated cortical electric fields with the 4×1 montage were compared (area, magnitude, direction) for TES and tDCS in each subject. We provide direct evidence in humans that TES with a 4×1-Ring configuration can activate motor cortex and that current does not substantially spread outside the stimulation area. Computational models predict that both TES and tDCS waveforms using the 4×1-Ring configuration generate electric fields in cortex with comparable gross current distribution, and preferentially directed normal (inward) currents. The agreement of modeling and experimental data for both current delivery and focality support the use of the HD-tDCS 4×1-Ring montage for cortically targeted neuromodulation. PMID:23370061

  11. Small-sized and contacting Pt-WC nanostructures on graphene as highly efficient anode catalysts for direct methanol fuel cells.

    Science.gov (United States)

    Wang, Ruihong; Xie, Ying; Shi, Keying; Wang, Jianqiang; Tian, Chungui; Shen, Peikang; Fu, Honggang

    2012-06-11

    The synergistic effect between Pt and WC is beneficial for methanol electro-oxidation, and makes Pt-WC catalyst a promising anode candidate for the direct methanol fuel cell. This paper reports on the design and synthesis of small-sized and contacting Pt-WC nanostructures on graphene that bring the synergistic effect into full play. Firstly, DFT calculations show the existence of a strong covalent interaction between WC and graphene, which suggests great potential for anchoring WC on graphene with formation of small-sized, well-dispersed WC particles. The calculations also reveal that, when Pt attaches to the pre-existing WC/graphene hybrid, Pt particles preferentially grow on WC rather than graphene. Our experiments confirmed that highly disperse WC nanoparticles (ca. 5 nm) can indeed be anchored on graphene. Also, Pt particles 2-3 nm in size are well dispersed on WC/graphene hybrid and preferentially grow on WC grains, forming contacting Pt-WC nanostructures. These results are consistent with the theoretical findings. X-ray absorption fine structure spectroscopy further confirms the intimate contact between Pt and WC, and demonstrates that the presence of WC can facilitate the crystallinity of Pt particles. This new Pt-WC/graphene catalyst exhibits a high catalytic efficiency toward methanol oxidation, with a mass activity 1.98 and 4.52 times those of commercial PtRu/C and Pt/C catalysts, respectively. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Improving the direct electron transfer in monolithic bioelectrodes prepared by immobilization of FDH enzyme on carbon-coated anodic aluminum oxide films

    Directory of Open Access Journals (Sweden)

    Alberto eCastro-Muñiz

    2016-02-01

    Full Text Available The present work reports the preparation of binderless carbon-coated porous films and the study of their performance as monolithic bioanodes. The films were prepared by coating anodic aluminum oxide (AAO films with a thin layer of nitrogen-doped carbon by chemical vapor deposition. The films have cylindrical straight pores with controllable diameter and length. These monolithic films were used directly as bioelectrodes by loading the films with D-fructose dehydrogenase (FDH, an oxidoreductase enzyme that catalyzes the oxidation of D-fructose to 5-keto-D-fructose. The immobilization of the enzymes was carried out by physical adsorption in liquid phase and with an electrostatic attraction method. The latter method takes advantage of the fact that FDH is negatively charged during the catalytic oxidation of fructose. Thus the immobilization was performed under the application of a positive voltage to the CAAO film in a FDH-fructose solution in McIlvaine buffer (pH 5 at 25 ºC. As a result, the FDH modified electrodes with the latter method show much better electrochemical response than that with the conventional physical adsorption method. Due to the singular porous structure of the monolithic films, which consists of an array of straight and parallel nanochannels, it is possible to rule out the effect of the diffusion of the D-fructose into the pores. Thus the improvement in the performance upon using the electrostatic attraction method can be ascribed not only to a higher uptake, but also to a more appropriate molecule orientation of the enzyme units on the surface of the electrodes.

  13. Precondition of right frontal region with anodal tDCS can restore the fear memory impairment induced by ACPA in male mice.

    Science.gov (United States)

    Manteghi, Fariborz; Nasehi, Mohammad; Zarrindast, Mohammad-Reza

    2017-01-01

    Fear memory and learning cause behavioural patterns such as fight or flight responses, which increase survival probability, but unfit processing of fear memory and learning can lead to maladaptive behaviours and maladies such as phobias, Post-Traumatic Stress Disorder (PTSD) and anxiety disorders. The growing prevalence of these maladies shows the need to quest novel methods for their treatment. We used anodal transcranial direct current stimulation (tDCS) on the right frontal region as a precondition neuromodulator and arachidonylcyclopropylamide (ACPA), a selective CB1 cannabinoid receptor agonist, as a fear memory impairing agent to assess their effects on contextual and auditory fear conditioning (reliable model for fear studies). Right frontal anodal tDCS (0.2 mA for. 20 minutes) 24 hours before the train did not alter contextual and auditory learning and memory in short-term (24 hrs after the training phase). Moreover, intraperitoneal pre-train injection of ACPA (0.1 mg/kg) alone, decreased both contextual and auditory learning and memory in short- but not long-term. Right frontal anodal tDCS improved short-term contextual fear memory in subthreshold doses of ACPA. On the other hand, right frontal anodal tDCS in long-term improved (lower doses of ACPA) and restored (higher doses of ACPA) both fear memories. These findings showed that, aforementioned approach could cause durable learning and memory improvements. Also this combined modality could be useful for fear extinction training and maladies which inflict amnesia.

  14. [Transcranial magnetic stimulation].

    Science.gov (United States)

    Tormos, J M; Catalá, M D; Pascual-Leone, A

    Transcranial magnetic stimulation (TMS) permits stimulation of the cerebral cortex in humans without requiring open access to the brain and is one of the newest tools available in neuroscience. There are two main types of application: single-pulse TMS and repetitive TMS. The magnetic stimulator is composed of a series of capacitors that store the voltage necessary to generate a stimulus of the sufficient intensity of generate an electric field in the stimulation coil. The safety of TMS is supported by the considerable experience derived from studies involving electrical stimulation of the cortex in animals and humans, and also specific studies on the safety of TMS in humans. In this article we review historical and technical aspects of TMS, describe its adverse effects and how to avoid them, summarize the applications of TMS in the investigation of different cerebral functions, and discuss the possibility of using TMS for the treatment of neuropsychiatric disorders.

  15. Anodal tDCS to Right Dorsolateral Prefrontal Cortex Facilitates Performance for Novice Jazz Improvisers but Hinders Experts.

    Science.gov (United States)

    Rosen, David S; Erickson, Brian; Kim, Youngmoo E; Mirman, Daniel; Hamilton, Roy H; Kounios, John

    2016-01-01

    Research on creative cognition reveals a fundamental disagreement about the nature of creative thought, specifically, whether it is primarily based on automatic, associative (Type-1) or executive, controlled (Type-2) processes. We hypothesized that Type-1 and Type-2 processes make differential contributions to creative production that depend on domain expertise. We tested this hypothesis with jazz pianists whose expertise was indexed by the number of public performances given. Previous fMRI studies of musical improvisation have reported that domain expertise is characterized by deactivation of the right-dorsolateral prefrontal cortex (r-DLPFC), a brain area associated with Type-2 executive processing. We used anodal, cathodal, and sham transcranial direct current stimulation (tDCS) applied over r-DLPFC with the reference electrode on the contralateral mastoid (1.5 mA for 15 min, except for sham) to modulate the quality of the pianists' performances while they improvised over chords with drum and bass accompaniment. Jazz experts rated each improvisation for creativity, esthetic appeal, and technical proficiency. There was no main effect of anodal or cathodal stimulation on ratings compared to sham; however, a significant interaction between anodal tDCS and expertise emerged such that stimulation benefitted musicians with less experience but hindered those with more experience. We interpret these results as evidence for a dual-process model of creativity in which novices and experts differentially engage Type-1 and Type-2 processes during creative production.

  16. Anodal tDCS to right dorsolateral prefrontal cortex facilitates performance for novice jazz improvisers but hinders experts

    Directory of Open Access Journals (Sweden)

    David S Rosen

    2016-11-01

    Full Text Available Research on creative cognition reveals a fundamental disagreement about the nature of creative thought, specifically, whether it is primarily based on automatic, associative (Type-1 or executive, controlled (Type-2 processes. We hypothesized that Type-1 and Type-2 processes make differential contributions to creative production that depend on domain expertise. We tested this hypothesis with jazz pianists whose expertise was indexed by the number of public performances given. Previous fMRI studies of musical improvisation have reported that domain expertise is characterized by deactivation of the right-dorsolateral prefrontal cortex (r-DLPFC, a brain area associated with Type-2 executive processing. We used anodal, cathodal, and sham transcranial direct-current stimulation (tDCS applied over r-DLPFC with the reference electrode on the contralateral mastoid (1.5mA for 15 min., except for sham to modulate the quality of the pianists’ performances while they improvised over chords with drum and bass accompaniment. Jazz experts rated each improvisation for creativity, aesthetic appeal, and technical proficiency. There was no main effect of anodal or cathodal stimulation on ratings compared to sham; however, a significant interaction between anodal tDCS and expertise emerged such that stimulation benefitted musicians with less experience but hindered those with more experience. We interpret these results as evidence for a dual-process model of creativity in which novices and experts differentially engage Type-1 and Type-2 processes during creative production.

  17. 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.

  18. Electrochemical performance and stability of Ni1-xCox-based cermet anode for direct methane-fuelled solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Nicharee Wongsawatgul

    2017-01-01

    Full Text Available Carbon deposition on Ni-based anode is well-known as a major barrier for the practical use and commercialization of hydrocarbon-fuelled solid oxide fuel cells (SOFCs. In this work, Co alloying in Ni-YSZ was studied as an alternative anode material for using CH4 as a fuel. The Ni-YSZ and Ni-Co alloyed-YSZ were prepared by the traditional impregnation method without further mixing processes. After sintering and reduction in H2 atmosphere, the introduced Co can completely dissolved into the Ni lattice and changed the morphology with an increase in the Ni-YSZ grain size and showed a better uniform microstructure. The Co alloying also enhanced the electrochemical performance under CH4 fuel by reducing the resistance and anodic overvoltage. Moreover, the Co addition enhanced the stability of the cell with CH4 a constant load current of 80 mA for 60 h. This performance related to the carbon deposition on the anode surface. The Co alloying showed a high efficiency to suppress the carbon deposition and improved the electrochemical performance of an SOFC cell operating under CH4 fuel.

  19. Cerebral ischemia: magnetic resonance angiography and transcranial Doppler evaluation.

    Science.gov (United States)

    D'Aprile, P; Federico, F; Medicamento, N; Conte, C; Carella, A

    1994-02-01

    We examined 21 patients with ischemic cerebrovascular disease using magnetic resonance angiography and transcranial Doppler. In 17 patients (81%), the results obtained by the two methods were concordant. In our opinion, the associated use of transcranial Doppler and magnetic resonance angiography provides an accurate diagnostic evaluation of ischemic stroke patients, not only allowing the site of possible steno-occlusive disease of large and medium cerebral vessels to be identified, but also offering the possibility of obtaining dynamic information concerning the direction of blood flow in the presence of compensatory circulations at the level of Willis' circle.

  20. FLUORINE CELL ANODE ASSEMBLY

    Science.gov (United States)

    Cable, R.E.; Goode, W.B. Jr.; Henderson, W.K.; Montillon, G.H.

    1962-06-26

    An improved anode assembly is deslgned for use in electrolytlc cells ln the productlon of hydrogen and fluorlne from a moIten electrolyte. The anode assembly comprises a copper post, a copper hanger supported by the post, a plurality of carbon anode members, and bolt means for clamplng half of the anode members to one slde of the hanger and for clamplng the other half of the anode members to the other slde of the hanger. The heads of the clamplng bolts are recessed withln the anode members and carbon plugs are inserted ln the recesses above the bolt heads to protect the boIts agalnst corroslon. A copper washer is provided under the head of each clamplng boIt such that the anode members can be tightly clamped to the hanger with a resultant low anode jolnt resistance. (AEC)

  1. Would transcranial direct current stimulation (tDCS) enhance the effects of working memory training in older adults with mild neurocognitive disorder due to Alzheimer's disease: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Cheng, Calvin P W; Chan, Sandra S M; Mak, Arthur D P; Chan, Wai Chi; Cheng, Sheung Tak; Shi, Lin; Wang, Defeng; Lam, Linda Chiu-Wa

    2015-10-24

    There has been longstanding interesting in cognitive training for older adults with cognitive impairment. In this study, we will investigate the effects of working memory training, and explore augmentation strategies that could possibly consolidate the effects in older adults with mild neurocognitive disorder. Transcranial direct current stimulation (tDCS) has been demonstrated to affect the neuronal excitability and reported to enhance memory performance. As tDCS may also modulate cognitive function through changes in neuroplastic response, it would be adopted as an augmentation strategy for working memory training in the present study. This is a 4-week intervention double-blind randomized controlled trial (RCT) of tDCS. Chinese older adults (aged 60 to 90 years) with mild neurocognitive disorder due to Alzheimer's disease (DSM-5 criteria) would be randomized into a 4-week intervention of either tDCS-working memory (DCS-WM), tDCS-control cognitive training (DCS-CC), and sham tDCS-working memory (WM-CD) groups. The primary outcome would be working memory test - the n-back task performance and the Chinese version of the Alzheimer's Disease Assessment Scale - Cognitive Subscale (ADAS-Cog). Secondary outcomes would be test performance of specific cognitive domains and mood. Intention-to-treat analysis would be carried out. Changes of efficacy indicators with time and intervention would be tested with mixed effect models. This study adopts the theory of neuroplasticity to evaluate the potential cognitive benefits of non-invasive electrical brain stimulation, working memory training and dual stimulation in older adults at risk of cognitive decline. It would also examine the tolerability, program adherence and adverse effects of this novel intervention. Information would be helpful for further research of dementia prevention studies. ChiCTR-TRC- 14005036 Date of registration: 31 July 2014.

  2. Corticospinal excitability changes to anodal tDCS elucidated with NIRS-EEG joint-imaging

    DEFF Research Database (Denmark)

    Jindal, Utkarsh; Sood, Mehak; Chowdhury, Shubhajit Roy

    2015-01-01

    with changes in the log-transformed mean-power of EEG within 0.5 Hz - 11.25 Hz. In two separate studies, we investigated local post-tDCS alterations from baseline at the site of anodal tDCS using NIRS-EEG/tDCS joint-imaging as well as local post-tDCS alterations in motor evoked potentials (MEP......Transcranial direct current stimulation (tDCS) has been shown to modulate corticospinal excitability. We used near-infrared spectroscopy (NIRS) - electroencephalography (EEG) joint-imaging during and after anodal tDCS to measure changes in mean cerebral haemoglobin oxygen saturation (rSO2) along......)-measure of corticospinal excitability. In the first study, we found that post-tDCS changes in the mean rSO2 from baseline mostly correlated with the corresponding post-tDCS change in log-transformed mean-power of EEG within 0.5 Hz - 11.25 Hz. Moreover, a decrease in log-transformed mean-power of EEG within 0.5 Hz - 11...

  3. 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,