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Sample records for higher stimulation frequencies

  1. Frequency shifts in stimulated Raman scattering

    International Nuclear Information System (INIS)

    Zinth, W.; Kaiser, W.

    1980-01-01

    The nonresonant contributions to the nonlinear susceptibility chisup(()3) produce a frequency chirp during stimulated Raman scattering. In the case of transient stimulated Raman scattering, the spectrum of the generated Stokes pulse is found at higher frequencies than expected from spontaneous Raman data. The frequency difference can be calculated from the theory of stimulated Raman scattering. (orig.)

  2. Effects of contraction mode and stimulation frequency on electrical stimulation-induced skeletal muscle hypertrophy.

    Science.gov (United States)

    Ashida, Yuki; Himori, Koichi; Tatebayashi, Daisuke; Yamada, Ryotaro; Ogasawara, Riki; Yamada, Takashi

    2018-02-01

    We compared the skeletal muscle hypertrophy resulting from isometric (Iso) or eccentric (Ecc) electrical stimulation (ES) training with different stimulation frequencies. Male Wistar rats were assigned to the Iso and Ecc groups. These were divided into three further subgroups that were stimulated at 10 Hz (Iso-10 and Ecc-10), 30 Hz (Iso-30 and Ecc-30), or 100 Hz (Iso-100 and Ecc-100). In experiment 1, the left plantarflexor muscles were stimulated every other day for 3 wk. In experiment 2, mammalian target of rapamycin complex 1 (mTORC1) signaling was investigated 6 h after one bout of ES. The contralateral right muscle served as a control (non-ES). Ecc contractions comprised forced dorsiflexion combined with ES. The peak torque and torque-time integral during ES were higher in the Ecc group than that in the Iso group in all stimulation frequencies examined. The gastrocnemius muscle weight normalized to body weight in ES side was increased compared with the non-ES side by 6, 7, and 17% in the Ecc-30, Iso-100, and Ecc-100 groups, respectively, with a greater gain in Ecc-100 than the Ecc-30 and Iso-100 groups. The p70S6K (Thr389) phosphorylation level was higher in the Ecc-30 and -100 than in the Iso-30 and -100 groups, respectively. The peak torque and torque-time integral were highly correlated with the magnitude of increase in muscle mass and the phosphorylation of p70S6K. These data suggest that ES-induced muscle hypertrophy and mTORC1 activity are determined by loading intensity and volume during muscle contraction independent of the contraction mode. NEW & NOTEWORTHY Eccentric contraction and high-frequency stimulation (HFS) are regarded as an effective way to increase muscle mass by electrical stimulation (ES) training. However, little is known about whether muscle hypertrophy is affected by contraction mode and stimulation frequency in ES training. Here, we provide the evidence that muscle hypertrophy and mammalian target of rapamycin complex 1 activity are

  3. Investigation of the Relationship Between Electrical Stimulation Frequency and Muscle Frequency Response Under Submaximal Contractions.

    Science.gov (United States)

    Papcke, Caluê; Krueger, Eddy; Olandoski, Marcia; Nogueira-Neto, Guilherme Nunes; Nohama, Percy; Scheeren, Eduardo Mendonça

    2018-03-25

    Neuromuscular electrical stimulation (NMES) is a common tool that is used in clinical and laboratory experiments and can be combined with mechanomyography (MMG) for biofeedback in neuroprostheses. However, it is not clear if the electrical current applied to neuromuscular tissues influences the MMG signal in submaximal contractions. The objective of this study is to investigate whether the electrical stimulation frequency influences the mechanomyographic frequency response of the rectus femoris muscle during submaximal contractions. Thirteen male participants performed three maximal voluntary isometric contractions (MVIC) recorded in isometric conditions to determine the maximal force of knee extensors. This was followed by the application of nine modulated NMES frequencies (20, 25, 30, 35, 40, 45, 50, 75, and 100 Hz) to evoke 5% MVIC. Muscle behavior was monitored by the analysis of MMG signals, which were decomposed into frequency bands by using a Cauchy wavelet transform. For each applied electrical stimulus frequency, the mean MMG spectral/frequency response was estimated for each axis (X, Y, and Z axes) of the MMG sensor with the values of the frequency bands used as weights (weighted mean). Only with respect to the Z (perpendicular) axis of the MMG signal, the stimulus frequency of 20 Hz did not exhibit any difference with the weighted mean (P = 0.666). For the frequencies of 20 and 25 Hz, the MMG signal displayed the bands between 12 and 16 Hz in the three axes (P frequencies from 30 to 100 Hz, the muscle presented a higher concentration of the MMG signal between the 22 and 29 Hz bands for the X and Z axes, and between 16 and 34 Hz bands for the Y axis (P frequency, because their frequency contents tend to mainly remain between the 20- and 25-Hz bands. Hence, NMES does not interfere with the use of MMG in neuroprosthesis. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  4. High frequency oscillations evoked by peripheral magnetic stimulation.

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    Biller, S; Simon, L; Fiedler, P; Strohmeier, D; Haueisen, J

    2011-01-01

    The analysis of somatosensory evoked potentials (SEP) and / or fields (SEF) is a well-established and important tool for investigating the functioning of the peripheral and central human nervous system. A standard technique to evoke SEPs / SEFs is the stimulation of the median nerve by using a bipolar electrical stimulus. We aim at an alternative stimulation technique enabling stimulation of deep nerve structures while reducing patient stress and error susceptibility. In the current study, we apply a commercial transcranial magnetic stimulation system for peripheral magnetic stimulation of the median nerve. We compare the results of simultaneously recorded EEG signals to prove applicability of our technique to evoke SEPs including low frequency components (LFC) as well as high frequency oscillations (HFO). Therefore, we compare amplitude, latency and time-frequency characteristics of the SEP of 14 healthy volunteers after electric and magnetic stimulation. Both low frequency components and high frequency oscillations were detected. The HFOs were superimposed onto the primary cortical response N20. Statistical analysis revealed significantly lower amplitudes and increased latencies for LFC and HFO components after magnetic stimulation. The differences indicate the inability of magnetic stimulation to elicit supramaximal responses. A psycho-perceptual evaluation showed that magnetic stimulation was less unpleasant for 12 out of the 14 volunteers. In conclusion, we showed that LFC and HFO components related to median nerve stimulation can be evoked by peripheral magnetic stimulation.

  5. High frequency switched-mode stimulation can evoke postsynaptic responses in cerebellar principal neurons

    Directory of Open Access Journals (Sweden)

    Marijn Van Dongen

    2015-03-01

    Full Text Available This paper investigates the efficacy of high frequency switched-mode neural stimulation. Instead of using a constant stimulation amplitude, the stimulus is switched on and off repeatedly with a high frequency (up to 100kHz duty cycled signal. By means of tissue modeling that includes the dynamic properties of both the tissue material as well as the axon membrane, it is first shown that switched-mode stimulation depolarizes the cell membrane in a similar way as classical constant amplitude stimulation.These findings are subsequently verified using in vitro experiments in which the response of a Purkinje cell is measured due to a stimulation signal in the molecular layer of the cerebellum of a mouse. For this purpose a stimulator circuit is developed that is able to produce a monophasic high frequency switched-mode stimulation signal. The results confirm the modeling by showing that switched-mode stimulation is able to induce similar responses in the Purkinje cell as classical stimulation using a constant current source. This conclusion opens up possibilities for novel stimulation designs that can improve the performance of the stimulator circuitry. Care has to be taken to avoid losses in the system due to the higher operating frequency.

  6. Effect of higher frequency on the classification of steady-state visual evoked potentials

    Science.gov (United States)

    Won, Dong-Ok; Hwang, Han-Jeong; Dähne, Sven; Müller, Klaus-Robert; Lee, Seong-Whan

    2016-02-01

    Objective. Most existing brain-computer interface (BCI) designs based on steady-state visual evoked potentials (SSVEPs) primarily use low frequency visual stimuli (e.g., visual fatigue and no stimulus-related seizures. The fundamental objective of this study was to investigate the effect of stimulation frequency and duty-cycle on the usability of an SSVEP-based BCI system. Approach. We developed an SSVEP-based BCI speller using multiple LEDs flickering with low frequencies (6-14.9 Hz) with a duty-cycle of 50%, or higher frequencies (26-34.7 Hz) with duty-cycles of 50%, 60%, and 70%. The four different experimental conditions were tested with 26 subjects in order to investigate the impact of stimulation frequency and duty-cycle on performance and visual fatigue, and evaluated with a questionnaire survey. Resting state alpha powers were utilized to interpret our results from the neurophysiological point of view. Main results. The stimulation method employing higher frequencies not only showed less visual fatigue, but it also showed higher and more stable classification performance compared to that employing relatively lower frequencies. Different duty-cycles in the higher frequency stimulation conditions did not significantly affect visual fatigue, but a duty-cycle of 50% was a better choice with respect to performance. The performance of the higher frequency stimulation method was also less susceptible to resting state alpha powers, while that of the lower frequency stimulation method was negatively correlated with alpha powers. Significance. These results suggest that the use of higher frequency visual stimuli is more beneficial for performance improvement and stability as time passes when developing practical SSVEP-based BCI applications.

  7. Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation.

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    Chen, Chiun-Fan; Bikson, Marom; Chou, Li-Wei; Shan, Chunlei; Khadka, Niranjan; Chen, Wen-Shiang; Fregni, Felipe

    2017-03-03

    It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train which induces force enhancements with a corticospinal contribution. We report that the electrical-stimulation-induced force enhancements were correlated with the amplitude of stimulation power harmonics during the amplitude-adapted pulse train. In an exploratory analysis, different levels of correlation were observed between force enhancement and power harmonics of 20-80 Hz (r = 0.4247, p = 0.0243), 100-180 Hz (r = 0.5894, p = 0.0001), 200-280 Hz (r = 0.7002, p harmonics. This is a pilot, but important first demonstration that power at high order harmonics in the frequency spectrum of electrical stimulation pulses may contribute to neuromodulation, thus warrant explicit attention in therapy design and analysis.

  8. Piping system damping data at higher frequencies

    International Nuclear Information System (INIS)

    Ware, A.G.

    1987-01-01

    Research has been performed at the Idaho National Engineering Laboratory (INEL) for the United States Nuclear Regulatory Commission (USNRC) to determine best-estimate damping values for dynamic analyses of nuclear piping systems excited in the 20 to 100 Hz frequency range. Vibrations in this frequency range are typical of fluid-induced transients, for which no formal pipe damping guidelines exist. The available data found in the open literature and the USNRC/INEL nuclear piping damping data bank were reviewed, and a series of tests on a straight 3-in. (76-mm) piping system and a 5-in. (127-mm) system with several bends and elbows were conducted as part of this research program. These two systems were supported with typical nuclear piping supports that could be changed from test to test during the series. The resulting damping values were ≥ those of the Pressure Vessel Research Committee (PVRC) proposal for unisulated piping. Extending the PVRC damping curve from 20 to 100 Hz at 3% of critical damping would give a satisfactory representation of the test data. This position has been endorsed by the PVRC Technical Committee on Piping Systems. 14 refs

  9. Frequency-time behavior of artificially stimulated vlf emissions

    International Nuclear Information System (INIS)

    Stiles, G.S.; Helliwell, R.A.

    1975-01-01

    Artificially stimulated VLF emissions (ASE's) are emissions triggered in the magnetosphere by the whistler mode signals from VLF transmitters. These emissions may be separated into two classes, rising and falling, depending on whether the final value of df/dt is positive or negative. Several hundred ASE's triggered by three transmitters have been analyzed using the fast Fourier transform with a filter spacing of 25 Hz and an effective filter width of about 45 Hz. The study was limited to the initial frequency-time behavior of ASE's. Averages taken over many events reveal that both rising and falling tones show the same initial behavior. The emissions begin at the frequency of the triggering signal. Both tones initially rise in frequency, falling tones reversing slope at a point 25--300 Hz above the triggering signal. The slope of rising tones, particularly those triggered by NAA, often abruptly levels off in this same frequency range; as a result, a short (approximately 40 ms) plateau is formed that precedes the final rising phase. The initial frequency offset commonly observed in individual events appears to result from the frequent coincidence with this plateau of a peak in amplitude. Emissions stimulated by all three transmitters show essentially the same features; this finding indicates that their frequency behavior does not depend strongly on transmitter power. The process appears to be asymmetric in frequency; no evidence of initial growth below the triggering frequency has been found. (U.S.)

  10. High-Frequency Neuromuscular Electrical Stimulation Increases Anabolic Signaling.

    Science.gov (United States)

    Mettler, Joni A; Magee, Dillon M; Doucet, Barbara M

    2018-03-16

    Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation settings to increase muscle mass and strength. However, the effects of NMES on muscle growth are not clear and no human studies have compared anabolic signaling between low-frequency (LF-) and high-frequency (HF-) NMES. The purpose of this study was to determine the skeletal muscle anabolic signaling response to an acute bout of LF- and HF-NMES. Eleven young healthy volunteers (6 men; 5 women) received an acute bout of LF- (20 Hz) and HF- (60 Hz) NMES. Muscle biopsies were obtained from the vastus lateralis muscle prior to the first NMES treatment and 30-mins following each NMES treatment. Phosphorylation of the following key anabolic signaling proteins was measured by Western blot and proteins are expressed as a ratio of phosphorylated to total: mammalian target of rapamycin (mTOR), p70-S6 kinase 1 (S6K1), and eukaryotic initiation factor 4E binding protein 1 (4E-BP1). Compared to Pre-NMES, phosphorylation of mTOR was upregulated 40.2% for LF-NMES (P = 0.018) and 68.4% for HF-NMES (P 0.05). There were no differences between treatment conditions for 4E-BP1 phosphorylation (P > 0.05). An acute bout of LF- and HF-NMES upregulated anabolic signaling with HF-NMES producing a greater anabolic response compared to LF-NMES, suggesting that HF-stimulation may provide a stronger stimulus for processes that initiate muscle hypertrophy. Additionally, the stimulation frequency parameter should be considered by clinicians in the design of optimal NMES treatment protocols.

  11. One year double blind study of high vs low frequency subcallosal cingulate stimulation for depression.

    Science.gov (United States)

    Eitan, Renana; Fontaine, Denys; Benoît, Michel; Giordana, Caroline; Darmon, Nelly; Israel, Zvi; Linesky, Eduard; Arkadir, David; Ben-Naim, Shiri; Iserlles, Moshe; Bergman, Hagai; Hulse, Natasha; Abdelghani, Mohamed; McGuffin, Peter; Farmer, Anne; DeLea, Peichel; Ashkan, Keyoumars; Lerer, Bernard

    2018-01-01

    Subcallosal Brodmann's Area 25 (Cg25) Deep Brain Stimulation (DBS) is a new promising therapy for treatment resistant major depressive disorder (TR-MDD). While different DBS stimulating parameters may have an impact on the efficacy and safety of the therapy, there is no data to support a protocol for optimal stimulation parameters for depression. Here we present a prospective multi-center double-blind randomized crossed-over 13-month study that evaluated the effects of High (130 Hz) vs Low (20 Hz) frequency Cg25 stimulation for nine patients with TR-MDD. Four out of nine patients achieved response criteria (≥40% reduction of symptom score) compared to mean baseline values at the end of the study. The mean percent change of MADRS score showed a similar improvement in the high and low frequency stimulation groups after 6 months of stimulation (-15.4 ± 21.1 and -14.7 ± 21.1 respectively). The mean effect at the end of the second period (6 months after cross-over) was higher than the first period (first 6 months of stimulation) in all patients (-23.4 ± 19.9 (n = 6 periods) and -13.0 ± 22 (n = 9 periods) respectively). At the end of the second period, the mean percent change of the MADRS scores improved more in the high than low frequency groups (-31.3 ± 19.3 (n = 4 patients) and -7.7 ± 10.9 (n = 2 patients) respectively). Given the small numbers, detailed statistical analysis is challenging. Nonetheless the results of this study suggest that long term high frequency stimulation might confer the best results. Larger scale, randomized double blind trials are needed in order to evaluate the most effective stimulation parameters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Optical parametric amplification and oscillation assisted by low-frequency stimulated emission.

    Science.gov (United States)

    Longhi, Stefano

    2016-04-15

    Optical parametric amplification and oscillation provide powerful tools for coherent light generation in spectral regions inaccessible to lasers. Parametric gain is based on a frequency down-conversion process and, thus, it cannot be realized for signal waves at a frequency ω3 higher than the frequency of the pump wave ω1. In this Letter, we suggest a route toward the realization of upconversion optical parametric amplification and oscillation, i.e., amplification of the signal wave by a coherent pump wave of lower frequency, assisted by stimulated emission of the auxiliary idler wave. When the signal field is resonated in an optical cavity, parametric oscillation is obtained. Design parameters for the observation of upconversion optical parametric oscillation at λ3=465 nm are given for a periodically poled lithium-niobate (PPLN) crystal doped with Nd(3+) ions.

  13. Radio frequency plasma nitriding of aluminium at higher power levels

    International Nuclear Information System (INIS)

    Gredelj, Sabina; Kumar, Sunil; Gerson, Andrea R.; Cavallaro, Giuseppe P.

    2006-01-01

    Nitriding of aluminium 2011 using a radio frequency plasma at higher power levels (500 and 700 W) and lower substrate temperature (500 deg. C) resulted in higher AlN/Al 2 O 3 ratios than obtained at 100 W and 575 deg. C. AlN/Al 2 O 3 ratios derived from X-ray photoelectron spectroscopic analysis (and corroborated by heavy ion elastic recoil time of flight spectrometry) for treatments preformed at 100 (575 deg. C), 500 (500 deg. C) and 700 W (500 deg. C) were 1.0, 1.5 and 3.3, respectively. Scanning electron microscopy revealed that plasma nitrided surfaces obtained at higher power levels exhibited much finer nodular morphology than obtained at 100 W

  14. Novel Stimulation Paradigms with Temporally-Varying Parameters to Reduce Synchronous Activity at the Onset of High Frequency Stimulation in Rat Hippocampus

    Directory of Open Access Journals (Sweden)

    Ziyan Cai

    2017-10-01

    Full Text Available Deep brain stimulation (DBS has shown wide applications for treating various disorders in the central nervous system by using high frequency stimulation (HFS sequences of electrical pulses. However, upon the onset of HFS sequences, the narrow pulses could induce synchronous firing of action potentials among large populations of neurons and cause a transient phase of “onset response” that is different from the subsequent steady state. To investigate the transient onset phase, the antidromically-evoked population spikes (APS were used as an electrophysiological marker to evaluate the synchronous neuronal reactions to axonal HFS in the hippocampal CA1 region of anesthetized rats. New stimulation paradigms with time-varying intensity and frequency were developed to suppress the “onset responses”. Results show that HFS paradigms with ramp-up intensity at the onset phase could suppress large APS potentials. In addition, an intensity ramp with a slower ramp-up rate or with a higher pulse frequency had greater suppression on APS amplitudes. Therefore, to reach a desired pulse intensity rapidly, a stimulation paradigm combining elevated frequency and ramp-up intensity was used to shorten the transition phase of initial HFS without evoking large APS potentials. The results of the study provide important clues for certain transient side effects of DBS and for development of new adaptive stimulation paradigms.

  15. Stuttering in Parkinson's disease after deep brain stimulation: A note on dystonia and low-frequency stimulation.

    Science.gov (United States)

    Mendonça, Marcelo D; Barbosa, Raquel; Seromenho-Santos, Alexandra; Reizinho, Carla; Bugalho, Paulo

    2018-04-01

    Stuttering, a speech fluency disorder, is a rare complication of Deep Brain Stimulation (DBS) in Parkinson's Disease (PD). We report a 61 years-old patient with PD, afflicted by severe On and Off dystonia, treated with Subthalamic Nucleus DBS that developed post-DBS stuttering while on 130 Hz stimulation. Stuttering reduction was noted when frequency was changed to 80 Hz, but the previously observed dystonia improvement was lost. There are no reports in literature on patients developing stuttering with low-frequency stimulation. We question if low-frequency stimulation could have a role for managing PD's post-DBS stuttering, and notice that stuttering improvement was associated with dystonia worsening suggesting that they are distinct phenomena. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Electrical Stimulation Frequency and Skeletal Muscle Characteristics: Effects on Force and Fatigue

    Directory of Open Access Journals (Sweden)

    Maria Vromans

    2017-12-01

    Full Text Available This investigation aimed to determine the force and muscle surface electromyography (EMG responses to different frequencies of electrical stimulation (ES in two groups of muscles with different size and fiber composition (fast- and slow-twitch fiber proportions during a fatigue-inducing protocol. Progression towards fatigue was evaluated in the abductor pollicis brevis (APB and vastus lateralis (VL when activated by ES at three frequencies (10, 35, and 50Hz. Ten healthy adults (mean age: 23.2 ± 3.0 years were recruited; participants signed an IRB approved consent form prior to participation. Protocols were developed to 1 identify initial ES current intensity required to generate the 25% maximal voluntary contraction (MVC at each ES frequency and 2 evaluate changes in force and EMG activity during ES-induced contraction at each frequency while progressing towards fatigue. For both muscles, stimulation at 10Hz required higher current intensity of ES to generate the initial force. There was a significant decline in force in response to ES-induced fatigue for all frequencies and for both muscles (p<0.05. However, the EMG response was not consistent between muscles. During the progression towards fatigue, the APB displayed an initial drop in force followed by an increase in EMG activity and the VL displayed a decrease in EMG activity for all frequencies. Overall, it appeared that there were some significant interactions between muscle size and fiber composition during progression towards fatigue for different ES frequencies. It could be postulated that muscle characteristics (size and fiber composition should be considered when evaluating progression towards fatigue as EMG and force responses are not consistent between muscles.

  17. Extended Opacity Tables with Higher Temperature-Density-Frequency Resolution

    Science.gov (United States)

    Schillaci, Mark; Orban, Chris; Delahaye, Franck; Pinsonneault, Marc; Nahar, Sultana; Pradhan, Anil

    2015-05-01

    Theoretical models for plasma opacities underpin our understanding of radiation transport in many different astrophysical objects. These opacity models are also relevant to HEDP experiments such as ignition scale experiments on NIF. We present a significantly expanded set of opacity data from the widely utilized Opacity Project, and make these higher resolution data publicly available through OSU's portal with dropbox.com. This expanded data set is used to assess how accurate the interpolation of opacity data in temperature-density-frequency dimensions must be in order to adequately model the properties of most stellar types. These efforts are the beginning of a larger project to improve the theoretical opacity models in light of experimental results at the Sandia Z-pinch showing that the measured opacity of Iron disagrees strongly with all current models.

  18. Low and High Frequency Hippocampal Stimulation for Drug-Resistant Mesial Temporal Lobe Epilepsy.

    Science.gov (United States)

    Lim, Siew-Na; Lee, Ching-Yi; Lee, Shih-Tseng; Tu, Po-Hsun; Chang, Bao-Luen; Lee, Chih-Hong; Cheng, Mei-Yun; Chang, Chun-Wei; Tseng, Wei-En Johnny; Hsieh, Hsiang-Yao; Chiang, Hsing-I; Wu, Tony

    2016-06-01

    Electrical stimulation of the hippocampus offers the possibility to treat patients with mesial temporal lobe epilepsy (MTLE) who are not surgical candidates. We report long-term follow-up results in five patients receiving low or high frequency hippocampal stimulation for drug-resistant MTLE. The patients underwent stereotactic implantation of quadripolar stimulating electrodes in the hippocampus. Two of the patients received unilateral electrode implantation, while the other three received bilateral implantation. Stimulation of the hippocampal electrodes was turned ON immediately after the implantation of an implantable pulse generator, with initial stimulation parameters: 1 V, 90-150 μs, 5 or 145 Hz. The frequency of seizures was monitored and compared with preimplantation baseline data. Two men and three women, aged 27-61 years were studied, with a mean follow-up period of 38.4 months (range, 30-42 months). The baseline seizure frequency was 2.0-15.3/month. The five patients had an average 45% (range 22-72%) reduction in the frequency of seizures after hippocampal stimulation over the study period. Low frequency hippocampal stimulation decreased the frequency of seizures in two patients (by 54% and 72%, respectively). No implantation- or stimulation-related side effects were reported. Electrical stimulation of the hippocampus is a minimally invasive and reversible method that can improve seizure outcomes in patients with drug-resistant MTLE. The optimal frequency of stimulation varied from patient to patient and therefore required individual setting. These experimental results warrant further controlled studies with a large patient population to evaluate the long-term effect of hippocampal stimulation with different stimulation parameters. © 2016 The Authors. Neuromodulation: Technology at the Neural Interface published by Wiley Periodicals, Inc. on behalf of International Neuromodulation Society.

  19. Probing phase- and frequency-dependent characteristics of cortical interneurons using combined transcranial alternating current stimulation and transcranial magnetic stimulation.

    Science.gov (United States)

    Hussain, Sara J; Thirugnanasambandam, Nivethida

    2017-06-01

    Paired-pulse transcranial magnetic stimulation (TMS) and peripheral stimulation combined with TMS can be used to study cortical interneuronal circuitry. By combining these procedures with concurrent transcranial alternating current stimulation (tACS), Guerra and colleagues recently showed that different cortical interneuronal populations are differentially modulated by the phase and frequency of tACS-imposed oscillations (Guerra A, Pogosyan A, Nowak M, Tan H, Ferreri F, Di Lazzaro V, Brown P. Cerebral Cortex 26: 3977-2990, 2016). This work suggests that different cortical interneuronal populations can be characterized by their phase and frequency dependency. Here we discuss how combining TMS and tACS can reveal the frequency at which cortical interneuronal populations oscillate, the neuronal origins of behaviorally relevant cortical oscillations, and how entraining cortical oscillations could potentially treat brain disorders. Copyright © 2017 the American Physiological Society.

  20. Higher success rate with transcranial electrical stimulation of motor-evoked potentials using constant-voltage stimulation compared with constant-current stimulation in patients undergoing spinal surgery.

    Science.gov (United States)

    Shigematsu, Hideki; Kawaguchi, Masahiko; Hayashi, Hironobu; Takatani, Tsunenori; Iwata, Eiichiro; Tanaka, Masato; Okuda, Akinori; Morimoto, Yasuhiko; Masuda, Keisuke; Tanaka, Yuu; Tanaka, Yasuhito

    2017-10-01

    During spine surgery, the spinal cord is electrophysiologically monitored via transcranial electrical stimulation of motor-evoked potentials (TES-MEPs) to prevent injury. Transcranial electrical stimulation of motor-evoked potential involves the use of either constant-current or constant-voltage stimulation; however, there are few comparative data available regarding their ability to adequately elicit compound motor action potentials. We hypothesized that the success rates of TES-MEP recordings would be similar between constant-current and constant-voltage stimulations in patients undergoing spine surgery. The objective of this study was to compare the success rates of TES-MEP recordings between constant-current and constant-voltage stimulation. This is a prospective, within-subject study. Data from 100 patients undergoing spinal surgery at the cervical, thoracic, or lumbar level were analyzed. The success rates of the TES-MEP recordings from each muscle were examined. Transcranial electrical stimulation with constant-current and constant-voltage stimulations at the C3 and C4 electrode positions (international "10-20" system) was applied to each patient. Compound muscle action potentials were bilaterally recorded from the abductor pollicis brevis (APB), deltoid (Del), abductor hallucis (AH), tibialis anterior (TA), gastrocnemius (GC), and quadriceps (Quad) muscles. The success rates of the TES-MEP recordings from the right Del, right APB, bilateral Quad, right TA, right GC, and bilateral AH muscles were significantly higher using constant-voltage stimulation than those using constant-current stimulation. The overall success rates with constant-voltage and constant-current stimulations were 86.3% and 68.8%, respectively (risk ratio 1.25 [95% confidence interval: 1.20-1.31]). The success rates of TES-MEP recordings were higher using constant-voltage stimulation compared with constant-current stimulation in patients undergoing spinal surgery. Copyright © 2017

  1. Different stimulation frequencies alter synchronous fluctuations in motor evoked potential amplitude of intrinsic hand muscles – a TMS study.

    Directory of Open Access Journals (Sweden)

    Martin Victor Sale

    2016-03-01

    Full Text Available The amplitude of motor-evoked potentials (MEPs elicited with transcranial magnetic stimulation (TMS varies from trial-to-trial. Synchronous oscillations in cortical neuronal excitability contribute to this variability, however it is not known how different frequencies of stimulation influence MEP variability, and whether these oscillations are rhythmic or aperiodic. We stimulated the motor cortex with TMS at different regular (i.e., rhythmic rates, and compared this with pseudo-random (aperiodic timing. In 18 subjects, TMS was applied at three regular frequencies (0.05 Hz, 0.2 Hz, 1 Hz and one aperiodic frequency (mean 0.2 Hz. MEPs (n = 50 were recorded from three intrinsic hand muscles of the left hand with different functional and anatomical relations. MEP amplitude correlation was highest for the functionally related muscle pair, less for the anatomically related muscle pair and least for the functionally- and anatomically-unrelated muscle pair. MEP correlations were greatest with 1 Hz, and least for stimulation at 0.05 Hz. Corticospinal neuron synchrony is higher with shorter TMS intervals. Further, corticospinal neuron synchrony is similar irrespective of whether the stimulation is periodic or aperiodic. These findings suggest TMS frequency is a crucial consideration for studies using TMS to probe correlated activity between muscle pairs.

  2. Different Stimulation Frequencies Alter Synchronous Fluctuations in Motor Evoked Potential Amplitude of Intrinsic Hand Muscles—a TMS Study

    Science.gov (United States)

    Sale, Martin V.; Rogasch, Nigel C.; Nordstrom, Michael A.

    2016-01-01

    The amplitude of motor-evoked potentials (MEPs) elicited with transcranial magnetic stimulation (TMS) varies from trial-to-trial. Synchronous oscillations in cortical neuronal excitability contribute to this variability, however it is not known how different frequencies of stimulation influence MEP variability, and whether these oscillations are rhythmic or aperiodic. We stimulated the motor cortex with TMS at different regular (i.e., rhythmic) rates, and compared this with pseudo-random (aperiodic) timing. In 18 subjects, TMS was applied at three regular frequencies (0.05 Hz, 0.2 Hz, 1 Hz) and one aperiodic frequency (mean 0.2 Hz). MEPs (n = 50) were recorded from three intrinsic hand muscles of the left hand with different functional and anatomical relations. MEP amplitude correlation was highest for the functionally related muscle pair, less for the anatomically related muscle pair and least for the functionally- and anatomically-unrelated muscle pair. MEP correlations were greatest with 1 Hz, and least for stimulation at 0.05 Hz. Corticospinal neuron synchrony is higher with shorter TMS intervals. Further, corticospinal neuron synchrony is similar irrespective of whether the stimulation is periodic or aperiodic. These findings suggest TMS frequency is a crucial consideration for studies using TMS to probe correlated activity between muscle pairs. PMID:27014031

  3. Safety study of high-frequency transcranial magnetic stimulation in patients with chronic stroke.

    Science.gov (United States)

    Lomarev, M P; Kim, D Y; Richardson, S Pirio; Voller, B; Hallett, M

    2007-09-01

    Repetitive transcranial magnetic stimulation (rTMS) is a potential therapeutic tool to rehabilitate chronic stroke patients. In this study, the safety of high-frequency rTMS in stroke was investigated (Phase I). The safety of 20 and 25 Hz rTMS over the motor cortex (MC) of the affected hemisphere, with intensities of 110-130% of the motor threshold (MT), was evaluated using surface electromyography (EMG) of hand and arm muscles. Brief EMG bursts, possibly representing peripheral manifestations of after discharges, and spread of excitation to proximal muscles are considered to be associated with a high risk of seizure occurrence. These events were recorded after the rTMS trains. Neither increased MC excitability nor improved pinch force dynamometry was found after rTMS. Stimulation parameters for rTMS, which are safe for healthy volunteers, may lead to a higher risk for seizure occurrence in chronic stroke patients. rTMS at rates of 20 and 25 Hz using above threshold stimulation potentially increases the risk of seizures in patients with chronic stroke.

  4. Low-frequency electrical stimulation induces the proliferation and differentiation of peripheral blood stem cells into Schwann cells.

    Science.gov (United States)

    Gu, Xudong; Fu, Jianming; Bai, Jing; Zhang, Chengwen; Wang, Jing; Pan, Wenping

    2015-02-01

    stimulation group but higher than those in the ERK blockage group. Low-frequency electrical stimulation contributed to the proliferation of peripheral blood stem cells cultured in vitro and induced differentiation into Schwann cells. The ERK signaling pathway underlies cell proliferation and differentiation.

  5. Higher Eating Frequency Does Not Decrease Appetite in Healthy Adults.

    Science.gov (United States)

    Perrigue, Martine M; Drewnowski, Adam; Wang, Ching-Yun; Neuhouser, Marian L

    2016-01-01

    Consumption of small, frequent meals is suggested as an effective approach to control appetite and food intake and might be a strategy for weight loss or healthy weight maintenance. Despite much speculation on the topic, scientific evidence is limited to support such a relation in the absence of changes to diet composition. We examined the effects of high compared with low eating frequency (EF) on self-reported appetite as a secondary outcome in a controlled trial. We conducted a randomized, crossover intervention trial in 12 participants (4 men, 8 women) who completed 2 isocaloric 3-wk intervention phases of low EF (3 eating occasions/d) compared with high EF (8 eating occasions/d). On the last morning of each study phase, participants completed a 4-h appetite testing session. During the appetite testing session, participants completing the low EF phase consumed a meal at 0800. Participants completing the high EF intervention consumed the same meal spread evenly over 2 eating occasions at 0800 and 1030. Standardized ratings of hunger, desire to eat, fullness, thirst, and nausea were completed every 30 min with the use of paper-and-pencil semianchored 100-mm visual analog scales. A composite appetite score was calculated as the mean of hunger, desire to eat, and the inverse of fullness (calculated as 100-fullness rating). Linear regression analysis compared ratings between low EF and high EF conditions. The mean composite appetite score was higher in the high EF condition for the total testing period (baseline through 1200) (P appetite. This trial was registered at clinicaltrials.gov as NCT02548026. © 2016 American Society for Nutrition.

  6. Coral larvae settle at a higher frequency on red surfaces

    Science.gov (United States)

    Mason, B.; Beard, M.; Miller, M. W.

    2011-09-01

    Although chemical cues serve as the primary determinants of larval settlement and metamorphosis, light is also known to influence the behavior and the settlement of coral planulae. For example, Porites astreoides planulae settle preferentially on unconditioned red substrata. In order to test whether this behavior was a response to color and whether other species also demonstrate color preference, settlement choice experiments were conducted with P. astreoides and Acropora palmata. In these experiments, larvae were offered various types of plastic substrata representing three to seven different color choices. Both species consistently settled on red (or red and orange) substrata at a higher frequency than other colors. In one experiment, P. astreoides settled on 100% of red, plastic cable ties but failed to settle on green or white substrata. In a second experiment, 24% of larvae settled on red buttons, more than settled on six other colors combined. A. palmata settled on 80% of red and of orange cables ties but failed to settle on blue in one experiment and settled on a greater proportion of red acrylic squares than on four other colors or limestone controls in a second experiment. The consistency of the response across a variety of plastic materials suggests the response is related to long-wavelength photosensitivity. Fluorescence and reflectance spectra of experimental substrata demonstrated that the preferred substrata had spectra dominated by wavelengths greater than 550 nm with little or no reflection or emission of shorter wavelengths. These results suggest that some species of coral larvae may use spectral cues for fine-scale habitat selection during settlement. This behavior may be an adaptation to promote settlement in crustose coralline algae (CCA)-dominated habitats facilitating juvenile survival.

  7. Treatment of Chronic Refractory Neuropathic Pelvic Pain with High-Frequency 10-kilohertz Spinal Cord Stimulation.

    Science.gov (United States)

    Simopoulos, Thomas; Yong, Robert J; Gill, Jatinder S

    2017-11-06

    Chronic neuropathic pelvic pain remains a recalcitrant problem in the field of pain management. Case series on application of 10 kHz spinal cord stimulation is presented. High frequency stimulation can improve chronic neuropathic pain states that are known to be mediated at the conus medullaris and offers another avenue for the treatment of these patients. © 2017 World Institute of Pain.

  8. LTP in Hippocampal Area CA1 Is Induced by Burst Stimulation over a Broad Frequency Range Centered around Delta

    Science.gov (United States)

    Grover, Lawrence M.; Kim, Eunyoung; Cooke, Jennifer D.; Holmes, William R.

    2009-01-01

    Long-term potentiation (LTP) is typically studied using either continuous high-frequency stimulation or theta burst stimulation. Previous studies emphasized the physiological relevance of theta frequency; however, synchronized hippocampal activity occurs over a broader frequency range. We therefore tested burst stimulation at intervals from 100…

  9. Compact, Energy-Efficient High-Frequency Switched Capacitor Neural Stimulator With Active Charge Balancing.

    Science.gov (United States)

    Hsu, Wen-Yang; Schmid, Alexandre

    2017-08-01

    Safety and energy efficiency are two major concerns for implantable neural stimulators. This paper presents a novel high-frequency, switched capacitor (HFSC) stimulation and active charge balancing scheme, which achieves high energy efficiency and well-controlled stimulation charge in the presence of large electrode impedance variations. Furthermore, the HFSC can be implemented in a compact size without any external component to simultaneously enable multichannel stimulation by deploying multiple stimulators. The theoretical analysis shows significant benefits over the constant-current and voltage-mode stimulation methods. The proposed solution was fabricated using a 0.18 μm high-voltage technology, and occupies only 0.035 mm 2 for a single stimulator. The measurement result shows 50% peak energy efficiency and confirms the effectiveness of active charge balancing to prevent the electrode dissolution.

  10. Physiological recruitment of motor units by high-frequency electrical stimulation of afferent pathways.

    Science.gov (United States)

    Dideriksen, Jakob L; Muceli, Silvia; Dosen, Strahinja; Laine, Christopher M; Farina, Dario

    2015-02-01

    Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically evoked muscle activation is in several ways different from voluntary muscle contractions. These differences lead to challenges in the use of NMES for restoring muscle function. We investigated the use of low-current, high-frequency nerve stimulation to activate the muscle via the spinal motoneuron (MN) pool to achieve more natural activation patterns. Using a novel stimulation protocol, the H-reflex responses to individual stimuli in a train of stimulation pulses at 100 Hz were reliably estimated with surface EMG during low-level contractions. Furthermore, single motor unit recruitment by afferent stimulation was analyzed with intramuscular EMG. The results showed that substantially elevated H-reflex responses were obtained during 100-Hz stimulation with respect to a lower stimulation frequency. Furthermore, motor unit recruitment using 100-Hz stimulation was not fully synchronized, as it occurs in classic NMES, and the discharge rates differed among motor units because each unit was activated only after a specific number of stimuli. The most likely mechanism behind these observations is the temporal summation of subthreshold excitatory postsynaptic potentials from Ia fibers to the MNs. These findings and their interpretation were also verified by a realistic simulation model of afferent stimulation of a MN population. These results suggest that the proposed stimulation strategy may allow generation of considerable levels of muscle activation by motor unit recruitment that resembles the physiological conditions. Copyright © 2015 the American Physiological Society.

  11. Higher frequency network activity flow predicts lower frequency node activity in intrinsic low-frequency BOLD fluctuations.

    Science.gov (United States)

    Bajaj, Sahil; Adhikari, Bhim Mani; Dhamala, Mukesh

    2013-01-01

    The brain remains electrically and metabolically active during resting conditions. The low-frequency oscillations (LFO) of the blood oxygen level-dependent (BOLD) signal of functional magnetic resonance imaging (fMRI) coherent across distributed brain regions are known to exhibit features of this activity. However, these intrinsic oscillations may undergo dynamic changes in time scales of seconds to minutes during resting conditions. Here, using wavelet-transform based time-frequency analysis techniques, we investigated the dynamic nature of default-mode networks from intrinsic BOLD signals recorded from participants maintaining visual fixation during resting conditions. We focused on the default-mode network consisting of the posterior cingulate cortex (PCC), the medial prefrontal cortex (mPFC), left middle temporal cortex (LMTC) and left angular gyrus (LAG). The analysis of the spectral power and causal flow patterns revealed that the intrinsic LFO undergo significant dynamic changes over time. Dividing the frequency interval 0 to 0.25 Hz of LFO into four intervals slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), slow-3 (0.073-0.198 Hz) and slow-2 (0.198-0.25 Hz), we further observed significant positive linear relationships of slow-4 in-out flow of network activity with slow-5 node activity, and slow-3 in-out flow of network activity with slow-4 node activity. The network activity associated with respiratory related frequency (slow-2) was found to have no relationship with the node activity in any of the frequency intervals. We found that the net causal flow towards a node in slow-3 band was correlated with the number of fibers, obtained from diffusion tensor imaging (DTI) data, from the other nodes connecting to that node. These findings imply that so-called resting state is not 'entirely' at rest, the higher frequency network activity flow can predict the lower frequency node activity, and the network activity flow can reflect underlying structural

  12. Effects of low-frequency repetitive transcranial magnetic stimulation on event-related potential P300

    Science.gov (United States)

    Torii, Tetsuya; Sato, Aya; Iwahashi, Masakuni; Iramina, Keiji

    2012-04-01

    The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effects of low-frequency and short-term rTMS by stimulating the supramarginal gyrus (SMG), which is considered to be the related area of P300 origin. In addition, the prolonged stimulation effects on P300 latency were analyzed after applying rTMS. A figure-eight coil was used to stimulate left-right SMG, and intensity of magnetic stimulation was 80% of motor threshold. A total of 100 magnetic pulses were applied for rTMS. The effects of stimulus frequency at 0.5 or 1 Hz were determined. Following rTMS, an odd-ball task was performed and P300 latency of ERP was measured. The odd-ball task was performed at 5, 10, and 15 min post-rTMS. ERP was measured prior to magnetic stimulation as a control. Electroencephalograph (EEG) was measured at Fz, Cz, and Pz that were indicated by the international 10-20 electrode system. Results demonstrated that different effects on P300 latency occurred between 0.5-1 Hz rTMS. With 1 Hz low-frequency magnetic stimulation to the left SMG, P300 latency decreased. Compared to the control, the latency time difference was approximately 15 ms at Cz. This decrease continued for approximately 10 min post-rTMS. In contrast, 0.5 Hz rTMS resulted in delayed P300 latency. Compared to the control, the latency time difference was approximately 20 ms at Fz, and this delayed effect continued for approximately 15 min post-rTMS. Results demonstrated that P300 latency varied according to rTMS frequency. Furthermore, the duration of the effect was not similar for stimulus frequency of low-frequency rTMS.

  13. Basal ganglia dysfunction in OCD: subthalamic neuronal activity correlates with symptoms severity and predicts high-frequency stimulation efficacy.

    Science.gov (United States)

    Welter, M-L; Burbaud, P; Fernandez-Vidal, S; Bardinet, E; Coste, J; Piallat, B; Borg, M; Besnard, S; Sauleau, P; Devaux, B; Pidoux, B; Chaynes, P; Tézenas du Montcel, S; Bastian, A; Langbour, N; Teillant, A; Haynes, W; Yelnik, J; Karachi, C; Mallet, L

    2011-05-03

    Functional and connectivity changes in corticostriatal systems have been reported in the brains of patients with obsessive-compulsive disorder (OCD); however, the relationship between basal ganglia activity and OCD severity has never been adequately established. We recently showed that deep brain stimulation of the subthalamic nucleus (STN), a central basal ganglia nucleus, improves OCD. Here, single-unit subthalamic neuronal activity was analysed in 12 OCD patients, in relation to the severity of obsessions and compulsions and response to STN stimulation, and compared with that obtained in 12 patients with Parkinson's disease (PD). STN neurons in OCD patients had lower discharge frequency than those in PD patients, with a similar proportion of burst-type activity (69 vs 67%). Oscillatory activity was present in 46 and 68% of neurons in OCD and PD patients, respectively, predominantly in the low-frequency band (1-8 Hz). In OCD patients, the bursty and oscillatory subthalamic neuronal activity was mainly located in the associative-limbic part. Both OCD severity and clinical improvement following STN stimulation were related to the STN neuronal activity. In patients with the most severe OCD, STN neurons exhibited bursts with shorter duration and interburst interval, but higher intraburst frequency, and more oscillations in the low-frequency bands. In patients with best clinical outcome with STN stimulation, STN neurons displayed higher mean discharge, burst and intraburst frequencies, and lower interburst interval. These findings are consistent with the hypothesis of a dysfunction in the associative-limbic subdivision of the basal ganglia circuitry in OCD's pathophysiology.

  14. Time-frequency analysis of stimulus frequency otoacoustic emissions and their changes with efferent stimulation in guinea pigs

    Science.gov (United States)

    Berezina-Greene, Maria A.; Guinan, John J.

    2015-12-01

    To aid in understanding their origin, stimulus frequency otoacoustic emissions (SFOAEs) were measured at a series of tone frequencies using the suppression method, both with and without stimulation of medial olivocochlear (MOC) efferents, in anesthetized guinea pigs. Time-frequency analysis showed SFOAE energy peaks in 1-3 delay components throughout the measured frequency range (0.5-12 kHz). One component's delay usually coincided with the phase-gradient delay. When multiple delay components were present, they were usually near SFOAE dips. Below 2 kHz, SFOAE delays were shorter than predicted from mechanical measurements. With MOC stimulation, SFOAE amplitude was decreased at most frequencies, but was sometimes enhanced, and all SFOAE delay components were affected. The MOC effects and an analysis of model data suggest that the multiple SFOAE delay components arise at the edges of the traveling-wave peak, not far basal of the peak. Comparisons with published guinea-pig neural data suggest that the short latencies of low-frequency SFOAEs may arise from coherent reflection from an organ-of-Corti motion that has a shorter group delay than the traveling wave.

  15. Multisensory Stimulation to Improve Low- and Higher-Level Sensory Deficits after Stroke: A Systematic Review

    OpenAIRE

    Tinga, Angelica Maria; Visser-Meily, Johanna Maria Augusta; van der Smagt, Maarten Jeroen; Van der Stigchel, Stefan; van Ee, Raymond; Nijboer, Tanja Cornelia Wilhelmina

    2015-01-01

    The aim of this systematic review was to integrate and assess evidence for the effectiveness of multisensory stimulation (i.e., stimulating at least two of the following sensory systems: visual, auditory, and somatosensory) as a possible rehabilitation method after stroke. Evidence was considered with a focus on low-level, perceptual (visual, auditory and somatosensory deficits), as well as higher-level, cognitive, sensory deficits. We referred to the electronic databases Scopus and PubMed to...

  16. Time and frequency-dependent modulation of local field potential synchronization by deep brain stimulation.

    Directory of Open Access Journals (Sweden)

    Clinton B McCracken

    Full Text Available High-frequency electrical stimulation of specific brain structures, known as deep brain stimulation (DBS, is an effective treatment for movement disorders, but mechanisms of action remain unclear. We examined the time-dependent effects of DBS applied to the entopeduncular nucleus (EP, the rat homolog of the internal globus pallidus, a target used for treatment of both dystonia and Parkinson's disease (PD. We performed simultaneous multi-site local field potential (LFP recordings in urethane-anesthetized rats to assess the effects of high-frequency (HF, 130 Hz; clinically effective, low-frequency (LF, 15 Hz; ineffective and sham DBS delivered to EP. LFP activity was recorded from dorsal striatum (STR, ventroanterior thalamus (VA, primary motor cortex (M1, and the stimulation site in EP. Spontaneous and acute stimulation-induced LFP oscillation power and functional connectivity were assessed at baseline, and after 30, 60, and 90 minutes of stimulation. HF EP DBS produced widespread alterations in spontaneous and stimulus-induced LFP oscillations, with some effects similar across regions and others occurring in a region- and frequency band-specific manner. Many of these changes evolved over time. HF EP DBS produced an initial transient reduction in power in the low beta band in M1 and STR; however, phase synchronization between these regions in the low beta band was markedly suppressed at all time points. DBS also enhanced low gamma synchronization throughout the circuit. With sustained stimulation, there were significant reductions in low beta synchronization between M1-VA and STR-VA, and increases in power within regions in the faster frequency bands. HF DBS also suppressed the ability of acute EP stimulation to induce beta oscillations in all regions along the circuit. This dynamic pattern of synchronizing and desynchronizing effects of EP DBS suggests a complex modulation of activity along cortico-BG-thalamic circuits underlying the therapeutic

  17. Gender effect on discrimination of location and frequency in surface electrical stimulation.

    Science.gov (United States)

    Geng, Bo; Paramanathan, Senthoopiya A; Pedersen, Karina F; Lauridsen, Mette V; Gade, Julie; Lontis, Romulus; Jensen, Winnie

    2015-01-01

    This work investigated the gender effect on discrimination of surface electrical stimulation applied on the human forearm. Three experiments were conducted to examine the abilty of discriminating stimulation frequency, location, or both parameters in 14 healthy subjects. The results indicated a statistically significant impact of gender on the discrimination performance in all the three experiments (p gender difference in perceiving and interpreting electrical stimulation. Considering the gender difference may improve the efficacy of electrically evoked sensory feedback in applications such as prosthetic use and pain relief.

  18. High frequency repetitive sensory stimulation improves temporal discrimination in healthy subjects.

    Science.gov (United States)

    Erro, Roberto; Rocchi, Lorenzo; Antelmi, Elena; Palladino, Raffaele; Tinazzi, Michele; Rothwell, John; Bhatia, Kailash P

    2016-01-01

    High frequency electrical stimulation of an area of skin on a finger improves two-point spatial discrimination in the stimulated area, likely depending on plastic changes in the somatosensory cortex. However, it is unknown whether improvement also applies to temporal discrimination. Twelve young and ten elderly volunteers underwent the stimulation protocol onto the palmar skin of the right index finger. Somatosensory temporal discrimination threshold (STDT) was evaluated before and immediately after stimulation as well as 2.5h and 24h later. There was a significant reduction in somatosensory temporal threshold only on the stimulated finger. The effect was reversible, with STDT returning to the baseline values within 24h, and was smaller in the elderly than in the young participants. High frequency stimulation of the skin focally improves temporal discrimination in the area of stimulation. Given previous suggestions that the perceptual effects rely on plastic changes in the somatosensory cortex, our results are consistent with the idea that the timing of sensory stimuli is, at least partially, encoded in the primary somatosensory cortex. Such a protocol could potentially be used as a therapeutic intervention to ameliorate physiological decline in the elderly or in other disorders of sensorimotor integration. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  19. Higher frequency of cholelithiasis in eosinophilic cholecystitis, an unusual finding

    International Nuclear Information System (INIS)

    Sarfraz, T.; Tariq, H.; Bashir, S.

    2015-01-01

    To determine the frequency of cholelithiasis in eosinophilic cholecystitis in our population. Study Design: Prospective descriptive study. Place and Duration of Study: Histopathology department, Combined Military Hospital (CMH), Peshawar (Pakistan) from Dec 2011 to Nov 2014. Material and Methods: Eighteen hundred (1800) cholecystectomy specimens were included in the study. The specimens which were properly fixed in 10% formalin were included in the specimen, while poorly fixed and autolysed specimens were excluded. The specimens were examined grossly, measured and block selection was done. The slides made were examined under light microscope by one histopathologist and findings were analyzed. Results: Out of 1800 cholecystectomy specimens, 25 cases (1.38%) were diagnosed as eosinophilic cholecystitis. Out of these 25 cases, 20 (80%) were females having an age range of 30-50 years, while 5 (20%) were males with an age range of 35-55 years. Out of these 25 cases of eosinophilic cholecystitis, 22 (88%) were having cholelithiasis, while 3 (12%) were acalculous eosiniophilic cholecystitis. Conclusion: Eosinophilic cholecystitis in our population is mostly calculous which is very significant finding contrary to data given in western literature, where most of eosinophilic cholecystitis is aclculous. This needs further evaluation to determine any genetic, geographic, environmental, dietary, microbiological or any other factor responsible in etiopathogenesis of calculous eosinophilic cholecystitis in our population, which could be helpful in prevention and management of this disease. (author)

  20. Increased follicle-stimulating hormone is associated with higher assisted reproduction use after vasectomy reversal.

    Science.gov (United States)

    Hsiao, Wayland; Sultan, Raymond; Lee, Richard; Goldstein, Marc

    2011-06-01

    Of men with vasectomy 6% elect to have more children. When considering vasectomy reversal vs in vitro fertilization/intracytoplasmic sperm injection, an elucidation of preoperative factors that predict surgical success would help determine appropriate management. We tested the hypothesis that preoperative follicle-stimulating hormone 10 U/l or greater predict a lower paternity rate after vasectomy reversal. Using preoperative follicle-stimulating hormone levels we retrospectively reviewed the records of patients who underwent vasectomy reversal. Follicle-stimulating hormone was measured in cases suspicious for impaired spermatogenesis. The final analysis included 206 men, who were divided by follicle-stimulating hormone less than 10 U/l (normal in 155) and 10 U/l or greater (high in 51). Nominal logistic regression was performed to evaluate assisted reproduction predictors. Mean ± SD follicle-stimulating hormone in the normal and high groups was 5.1 ± 2.2 and 16.2 ± 6.2 U/l, respectively. Postoperative semen parameters were similar. However, in the high hormone group there was greater use of any type of assisted reproduction (78.4% vs 54.8%, p = 0.0028). On multivariate analysis follicle-stimulating hormone 10 U/l or greater (OR 3.02, 95% CI 1.34-6.83) and vasoepididymostomy that was bilateral or to a solitary testis (OR 3.26, 95% CI 1.09-9.69) was associated with greater assisted reproduction use. We evaluated preoperative follicle-stimulating hormone as a predictor of reproductive outcome in men with suspected subfertility who underwent vasectomy reversal. Increased follicle-stimulating hormone was associated with a higher rate of assisted reproduction even after controlling for confounding covariates. Thus, men with increased follicle-stimulating hormone should be counseled on the increased likelihood of needing assisted reproduction to achieve pregnancy after vasectomy reversal. Copyright © 2011 American Urological Association Education and Research, Inc

  1. High-frequency electrical stimulation can be a complementary therapy to promote nerve regeneration in diabetic rats.

    Directory of Open Access Journals (Sweden)

    Chia-Hong Kao

    Full Text Available The purpose of this study was to evaluate whether 1 mA of percutaneous electrical stimulation (ES at 0, 2, 20, or 200 Hz augments regeneration between the proximal and distal nerve stumps in streptozotocin diabetic rats. A10-mm gap was made in the diabetic rat sciatic nerve by suturing the stumps into silicone rubber tubes. Normal animals were used as the controls. Starting 1 week after transection, ES was applied between the cathode placed at the distal stump and the anode at the proximal stump every other day for 3 weeks. At 4 weeks after surgery, the normal controls and the groups receiving ES at 20, and 200 Hz had a higher success percentage of regeneration compared to the ES groups at 0 and 2 Hz. In addition, quantitative histology of the successfully regenerated nerves revealed that the groups receiving ES at a higher frequency, especially at 200 Hz, had a more mature structure with more myelinated fibers compared to those in the lower-frequency ES groups. Similarly, electrophysiology in the ES group at 200 Hz showed significantly shorter latency, larger amplitude, larger area of evoked muscle action potentials and faster conduction velocity compared to other groups. Immunohistochemical staining showed that ES at a higher frequency could significantly promote calcitonin gene-related peptide expression in lamina I-II regions in the dorsal horn and recruit a higher number of macrophages in the diabetic distal sciatic nerve. The macrophages were found that they could stimulate the secretion of nerve growth factor, platelet-derived growth factor, and transforming growth factor-β in dissected sciatic nerve segments. The ES at a higher frequency could also increase cutaneous blood flow in the ipsilateral hindpaw to the injury. These results indicated that a high-frequency ES could be necessary to heal severed diabetic peripheral nerve with a long gap to be repaired.

  2. Multisensory Stimulation to Improve Low- and Higher-Level Sensory Deficits after Stroke: A Systematic Review.

    Science.gov (United States)

    Tinga, Angelica Maria; Visser-Meily, Johanna Maria Augusta; van der Smagt, Maarten Jeroen; Van der Stigchel, Stefan; van Ee, Raymond; Nijboer, Tanja Cornelia Wilhelmina

    2016-03-01

    The aim of this systematic review was to integrate and assess evidence for the effectiveness of multisensory stimulation (i.e., stimulating at least two of the following sensory systems: visual, auditory, and somatosensory) as a possible rehabilitation method after stroke. Evidence was considered with a focus on low-level, perceptual (visual, auditory and somatosensory deficits), as well as higher-level, cognitive, sensory deficits. We referred to the electronic databases Scopus and PubMed to search for articles that were published before May 2015. Studies were included which evaluated the effects of multisensory stimulation on patients with low- or higher-level sensory deficits caused by stroke. Twenty-one studies were included in this review and the quality of these studies was assessed (based on eight elements: randomization, inclusion of control patient group, blinding of participants, blinding of researchers, follow-up, group size, reporting effect sizes, and reporting time post-stroke). Twenty of the twenty-one included studies demonstrate beneficial effects on low- and/or higher-level sensory deficits after stroke. Notwithstanding these beneficial effects, the quality of the studies is insufficient for valid conclusion that multisensory stimulation can be successfully applied as an effective intervention. A valuable and necessary next step would be to set up well-designed randomized controlled trials to examine the effectiveness of multisensory stimulation as an intervention for low- and/or higher-level sensory deficits after stroke. Finally, we consider the potential mechanisms of multisensory stimulation for rehabilitation to guide this future research.

  3. Bilateral high frequency subthalamic stimulation in Parkinson's disease: long-term neurological follow-up

    NARCIS (Netherlands)

    Romito, L. M.; Scerrati, M.; Contarino, M. F.; Iacoangeli, M.; Bentivoglio, A. R.; Albanese, A.

    2003-01-01

    AIM: High frequency stimulation of the subthalamic nucleus (STN) is gaining recognition as a new symptomatic treatment for Parkinson's disease (PD). The first available long-term observations show the stability of the efficacy of this procedure in time. METHODS: Quadripolar leads were implanted

  4. Frequency-specific masking effect by vibrotactile stimulation to the forearm

    NARCIS (Netherlands)

    Tanaka, Y.; Matsuoka, S.; Bergmann Tiest, W.M.; Kappers, A.M.L.; Minamizawa, K.; Sano, A.; Bello, F.; Kajimoto, H.; Visell, Y.

    2016-01-01

    This paper demonstrates frequency-specific masking of tactile sensations on the index finger by remote vibrotactile stimulation. A vibration of 50 Hz was presented to the index finger. In three experimental conditions, the detection threshold for this vibration was determined with a masking

  5. Accelerated high-frequency repetitive transcranial magnetic stimulation enhances motor activity in rats

    NARCIS (Netherlands)

    El Arfani, Anissa; Parthoens, Joke; Demuyser, Thomas; Servaes, Stijn; De Coninck, Mattias; De Deyn, Peter Paul; Van Dam, Debby; Wyckhuys, Tine; Baeken, Chris; Smolders, Ilse; Staelens, Steven

    2017-01-01

    High-frequency repetitive transcranial magnetic stimulation (HF-rTMS) is currently accepted as an evidence-based treatment option for treatment-resistant depression (TRD). Additionally, HF-rTMS showed beneficial effects on psychomotor retardation in patients. The classical HF-rTMS paradigms however

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

    Directory of Open Access Journals (Sweden)

    Christopher Gundlach

    2017-08-01

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

  7. Effective deep brain stimulation suppresses low frequency network oscillations in the basal ganglia by regularizing neural firing patterns

    Science.gov (United States)

    McConnell, George C.; So, Rosa Q.; Hilliard, Justin D; Lopomo, Paola; Grill, Warren M.

    2012-01-01

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for the motor symptoms of Parkinson’s disease (PD). The effects of DBS depend strongly on stimulation frequency: high frequencies (>90Hz) improve motor symptoms, while low frequencies (basal ganglia were studied in the unilateral 6-hydroxydopamine lesioned rat model of PD. Only high frequency DBS reversed motor symptoms and the effectiveness of DBS depended strongly on stimulation frequency in a manner reminiscent of its clinical effects in persons with PD. Quantification of single-unit activity in the globus pallidus externa (GPe) and substantia nigra reticulata (SNr) revealed that high frequency DBS, but not low frequency DBS, reduced pathological low frequency oscillations (~9Hz) and entrained neurons to fire at the stimulation frequency. Similarly, the coherence between simultaneously recorded pairs of neurons within and across GPe and SNr shifted from the pathological low frequency band to the stimulation frequency during high frequency DBS, but not during low frequency DBS. The changes in firing patterns in basal ganglia neurons were not correlated with changes in firing rate. These results indicate that high frequency DBS is more effective than low frequency DBS, not as a result of changes in firing rate, but rather due to its ability to replace pathological low frequency network oscillations with a regularized pattern of neuronal firing. PMID:23136407

  8. Effective deep brain stimulation suppresses low-frequency network oscillations in the basal ganglia by regularizing neural firing patterns.

    Science.gov (United States)

    McConnell, George C; So, Rosa Q; Hilliard, Justin D; Lopomo, Paola; Grill, Warren M

    2012-11-07

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for the motor symptoms of Parkinson's disease (PD). The effects of DBS depend strongly on stimulation frequency: high frequencies (>90 Hz) improve motor symptoms, while low frequencies (basal ganglia were studied in the unilateral 6-hydroxydopamine lesioned rat model of PD. Only high-frequency DBS reversed motor symptoms, and the effectiveness of DBS depended strongly on stimulation frequency in a manner reminiscent of its clinical effects in persons with PD. Quantification of single-unit activity in the globus pallidus externa (GPe) and substantia nigra reticulata (SNr) revealed that high-frequency DBS, but not low-frequency DBS, reduced pathological low-frequency oscillations (∼9 Hz) and entrained neurons to fire at the stimulation frequency. Similarly, the coherence between simultaneously recorded pairs of neurons within and across GPe and SNr shifted from the pathological low-frequency band to the stimulation frequency during high-frequency DBS, but not during low-frequency DBS. The changes in firing patterns in basal ganglia neurons were not correlated with changes in firing rate. These results indicate that high-frequency DBS is more effective than low-frequency DBS, not as a result of changes in firing rate, but rather due to its ability to replace pathological low-frequency network oscillations with a regularized pattern of neuronal firing.

  9. Effects of Low-frequency Current Sacral Dermatome Stimulation on Idiopathic Slow Transit Constipation.

    Science.gov (United States)

    Kim, Jin-Seop; Yi, Seung-Ju

    2014-06-01

    [Purpose] This study aimed to determine whether low-frequency current therapy can be used to reduce the symptoms of idiopathic slow transit constipation (ISTC). [Subjects] Fifteen patients (ten male and five female) with idiopathic slow transit constipation were enrolled in the present study. [Results] Bowel movements per day, bowel movements per week, and constipation assessment scale scores significantly improved after low-frequency current simulation of S2-S3. [Conclusion] Our results show that stimulation with low-frequency current of the sacral dermatomes may offer therapeutic benefits for a subject of patients with ISTC.

  10. Comparison of skin sensory thresholds using pre-programmed or single-frequency transcutaneous electrical nerve stimulation.

    Science.gov (United States)

    Kang, Jong Ho

    2015-12-01

    [Purpose] The purpose of the present study was to compare the sensory thresholds of healthy subjects using pre-programmed or single-frequency transcutaneous electrical nerve stimulation. [Subjects] Ninety healthy adult subjects were randomly assigned to pre-programmed or single-frequency stimulation groups, each consisting of 45 participants. [Methods] Sensory thresholds were measured in the participants' forearms using von Frey filaments before and after pre-programmed or single-frequency transcutaneous electrical nerve stimulation, and the result in values were analyzed. [Results] Significant increases in sensory threshold after stimulation were observed in both groups. However, there were no significant differences between the two groups in sensory thresholds after stimulation or in the magnitude of threshold increases following stimulation. [Conclusion] Our results show that there are no differences between sensory threshold increases induced by pre-programmed and single-frequency transcutaneous electrical nerve stimulation.

  11. Effects of Constant and Doublet Frequency Electrical Stimulation Patterns on Force Production of Knee Extensor Muscles.

    Directory of Open Access Journals (Sweden)

    Carole Cometti

    Full Text Available This study compared knee extensors' neuromuscular fatigue in response to two 30-minute stimulation patterns: constant frequency train (CFT and doublet frequency train (DFT. Fifteen men underwent two separate sessions corresponding to each pattern. Measurements included torque evoked by each contraction and maximal voluntary contractions (MVC measured before and immediately after the stimulation sessions. In addition, activation level and torque evoked during doublets (Pd and tetanic contractions at 80-Hz (P80 and 20-Hz (P20 were determined in six subjects. Results indicated greater mean torque during the DFT stimulation session as compared with CFT. But, no difference was obtained between the two stimulation patterns for MVC and evoked torque decreases. Measurements conducted in the subgroup depicted a significant reduction of Pd, P20 and P80. Statistical analyses also revealed bigger P20 immediate reductions after CFT than after DFT. We concluded that DFT could be a useful stimulation pattern to produce and maintain greater force with quite similar fatigue than CFT.

  12. Intermittent Theta Burst Stimulation Increases Reward Responsiveness in Individuals with Higher Hedonic Capacity.

    Science.gov (United States)

    Duprat, Romain; De Raedt, Rudi; Wu, Guo-Rong; Baeken, Chris

    2016-01-01

    Repetitive transcranial magnetic stimulation over the left dorsolateral prefrontal cortex (DLPFC) has been documented to influence striatal and orbitofrontal dopaminergic activity implicated in reward processing. However, the exact neuropsychological mechanisms of how DLPFC stimulation may affect the reward system and how trait hedonic capacity may interact with the effects remains to be elucidated. In this sham-controlled study in healthy individuals, we investigated the effects of a single session of neuronavigated intermittent theta burst stimulation (iTBS) on reward responsiveness, as well as the influence of trait hedonic capacity. We used a randomized crossover single session iTBS design with an interval of 1 week. We assessed reward responsiveness using a rewarded probabilistic learning task and measured individual trait hedonic capacity (the ability to experience pleasure) with the temporal experience of pleasure scale questionnaire. As expected, the participants developed a response bias toward the most rewarded stimulus (rich stimulus). Reaction time and accuracy for the rich stimulus were respectively shorter and higher as compared to the less rewarded stimulus (lean stimulus). Active or sham stimulation did not seem to influence the outcome. However, when taking into account individual trait hedonic capacity, we found an early significant increase in the response bias only after active iTBS. The higher the individual's trait hedonic capacity, the more the response bias toward the rich stimulus increased after the active stimulation. When taking into account trait hedonic capacity, one active iTBS session over the left DLPFC improved reward responsiveness in healthy male participants with higher hedonic capacity. This suggests that individual differences in hedonic capacity may influence the effects of iTBS on the reward system.

  13. Low-frequency stimulation of the external globus palladium produces anti-epileptogenic and anti-ictogenic actions in rats.

    Science.gov (United States)

    Cheng, Hui; Kuang, Yi-fang; Liu, Yang; Wang, Yi; Xu, Zheng-hao; Gao, Feng; Zhang, Shi-hong; Ding, Mei-ping; Chen, Zhong

    2015-08-01

    To investigate the anti-epileptic effects of deep brain stimulation targeting the external globus palladium (GPe) in rats. For inducing amygdala kindling and deep brain stimulation, bipolar stainless-steel electrodes were implanted in SD rats into right basolateral amygdala and right GPe, respectively. The effects of deep brain stimulation were evaluated in the amygdala kindling model, maximal electroshock model (MES) and pentylenetetrazole (PTZ) model. Moreover, the background EEGs in the amygdala and GPe were recorded. Low-frequency stimulation (0.1 ms, 1 Hz, 15 min) at the GPe slowed the progression of seizure stages and shortened the after-discharge duration (ADD) during kindling acquisition. Furthermore, low-frequency stimulation significantly decreased the incidence of generalized seizures, suppressed the average stage, and shortened the cumulative ADD and generalized seizure duration in fully kindled rats. In addition, low-frequency stimulation significantly suppressed the average stage of MES-induced seizures and increased the latency to generalized seizures in the PTZ model. High-frequency stimulation (0.1 ms, 130 Hz, 5 min) at the GPe had no anti-epileptic effect and even aggravated epileptogenesis induced by amygdala kindling. EEG analysis showed that low-frequency stimulation at the GPe reversed the increase in delta power, whereas high-frequency stimulation at the GPe had no such effect. Low-frequency stimulation, but not high-frequency stimulation, at the GPe exerts therapeutic effect on temporal lobe epilepsy and tonic-colonic generalized seizures, which may be due to interference with delta rhythms. The results suggest that modulation of GPe activity using low-frequency stimulation or drugs may be a promising epilepsy treatment.

  14. Modulation of EEG spectral edge frequency during patterned pneumatic oral stimulation in preterm infants

    Science.gov (United States)

    Song, Dongli; Jegatheesan, Priya; Weiss, Sunshine; Govindaswami, Balaji; Wang, Jingyan; Lee, Jaehoon; Oder, Austin; Barlow, Steven M

    2014-01-01

    Background Stimulation of the nervous system plays a central role in brain development and neurodevelopmental outcome. Thalamocortical and corticocortical development is diminished in premature infants and correlated to electroencephalography (EEG) progression. The purpose of this study was to determine the effects of orocutaneous stimulation on the modulation of spectral edge frequency, fc=90% (SEF-90) derived from EEG recordings in preterm infants. Methods Twenty two preterm infants were randomized to experimental and control conditions. Pulsed orocutaneous stimulation was presented during gavage feedings begun at around 32 weeks postmenstrual age (PMA). The SEF-90 was derived from 2-channel EEG recordings. Results Compared to the control condition, the pulsed orocutaneous stimulation produced a significant reorganization of SEF-90 in the left (p = 0.005) and right (p stimulation also produced a significant pattern of short term cortical adaptation and a long term neural adaptation manifest as a 0.5 Hz elevation in SEF-90 after repeated stimulation sessions. Conclusion This is the first study to demonstrate the modulating effects of a servo-controlled oral somatosensory input on the spectral features of EEG activity in preterm infants. PMID:24129553

  15. Auditory steady-state responses in cochlear implant users: Effect of modulation frequency and stimulation artifacts.

    Science.gov (United States)

    Gransier, Robin; Deprez, Hanne; Hofmann, Michael; Moonen, Marc; van Wieringen, Astrid; Wouters, Jan

    2016-05-01

    Previous studies have shown that objective measures based on stimulation with low-rate pulse trains fail to predict the threshold levels of cochlear implant (CI) users for high-rate pulse trains, as used in clinical devices. Electrically evoked auditory steady-state responses (EASSRs) can be elicited by modulated high-rate pulse trains, and can potentially be used to objectively determine threshold levels of CI users. The responsiveness of the auditory pathway of profoundly hearing-impaired CI users to modulation frequencies is, however, not known. In the present study we investigated the responsiveness of the auditory pathway of CI users to a monopolar 500 pulses per second (pps) pulse train modulated between 1 and 100 Hz. EASSRs to forty-three modulation frequencies, elicited at the subject's maximum comfort level, were recorded by means of electroencephalography. Stimulation artifacts were removed by a linear interpolation between a pre- and post-stimulus sample (i.e., blanking). The phase delay across modulation frequencies was used to differentiate between the neural response and a possible residual stimulation artifact after blanking. Stimulation artifacts were longer than the inter-pulse interval of the 500pps pulse train for recording electrodes ipsilateral to the CI. As a result the stimulation artifacts could not be removed by artifact removal on the bases of linear interpolation for recording electrodes ipsilateral to the CI. However, artifact-free responses could be obtained in all subjects from recording electrodes contralateral to the CI, when subject specific reference electrodes (Cz or Fpz) were used. EASSRs to modulation frequencies within the 30-50 Hz range resulted in significant responses in all subjects. Only a small number of significant responses could be obtained, during a measurement period of 5 min, that originate from the brain stem (i.e., modulation frequencies in the 80-100 Hz range). This reduced synchronized activity of brain stem

  16. Spiking irregularity and frequency modulate the behavioral report of single-neuron stimulation.

    Science.gov (United States)

    Doron, Guy; von Heimendahl, Moritz; Schlattmann, Peter; Houweling, Arthur R; Brecht, Michael

    2014-02-05

    The action potential activity of single cortical neurons can evoke measurable sensory effects, but it is not known how spiking parameters and neuronal subtypes affect the evoked sensations. Here, we examined the effects of spike train irregularity, spike frequency, and spike number on the detectability of single-neuron stimulation in rat somatosensory cortex. For regular-spiking, putative excitatory neurons, detectability increased with spike train irregularity and decreasing spike frequencies but was not affected by spike number. Stimulation of single, fast-spiking, putative inhibitory neurons led to a larger sensory effect compared to regular-spiking neurons, and the effect size depended only on spike irregularity. An ideal-observer analysis suggests that, under our experimental conditions, rats were using integration windows of a few hundred milliseconds or more. Our data imply that the behaving animal is sensitive to single neurons' spikes and even to their temporal patterning. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

    International Nuclear Information System (INIS)

    Franco, O.S.; Paulitsch, F.S.; Pereira, A.P.C.; Teixeira, A.O.; Martins, C.N.; Silva, A.M.V.; Plentz, R.D.M.; Irigoyen, M.C.; Signori, L.U.

    2014-01-01

    Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia

  18. Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Franco, O.S.; Paulitsch, F.S.; Pereira, A.P.C.; Teixeira, A.O. [Universidade Federal do Rio Grande, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Martins, C.N. [Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Fisiologia Animal Comparada, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Silva, A.M.V. [Universidade Federal de Santa Maria, Departamento de Fisioterapia e Reabilitação, Santa Maria, RS, Brasil, Departamento de Fisioterapia e Reabilitação, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Plentz, R.D.M. [Universidade Federal de Ciências da Saúde de Porto Alegre, Programa de Pós-Graduação em Ciências da Reabilitação, Programa de Pós-Graduação em Ciências da Saúde, Porto Alegre, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Programa de Pós-Graduação em Ciências da Reabilitação, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS (Brazil); Irigoyen, M.C. [Faculdade de Medicina, Universidade de São Paulo, Instituto do Coração, Unidade de Hipertensão, São Paulo, SP, Brasil, Unidade de Hipertensão, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Signori, L.U. [Universidade Federal do Rio Grande, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Fisiologia Animal Comparada, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Universidade Federal de Santa Maria, Departamento de Fisioterapia e Reabilitação, Santa Maria, RS, Brasil, Departamento de Fisioterapia e Reabilitação, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil)

    2014-04-04

    Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.

  19. Modulation of local field potentials by high-frequency stimulation of afferent axons in the hippocampal CA1 region.

    Science.gov (United States)

    Yu, Ying; Feng, Zhouyan; Cao, Jiayue; Guo, Zheshan; Wang, Zhaoxiang; Hu, Na; Wei, Xuefeng

    2016-03-01

    Modulation of the rhythmic activity of local field potentials (LFP) in neuronal networks could be a mechanism of deep brain stimulation (DBS). However, exact changes of LFP during the periods of high-frequency stimulation (HFS) of DBS are unclear because of the interference of dense stimulation artifacts with high amplitudes. In the present study, we investigated LFP changes induced by HFS of afferent axons in the hippocampal CA1 region of urethane-anesthetized rats by using a proper algorithm of artifact removal. Afterward, the LFP changes in the frequency bands of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] rhythms were studied by power spectrum analysis and coherence analysis for the recorded signals collected in the pyramidal layer and in the stratum radiatum of CA1 region before, during and after 1-min long 100 and 200[Formula: see text]Hz HFS. Results showed that the power of LFP rhythms in higher-frequency band ([Formula: see text] rhythm) increased in the pyramidal layer and the power of LFP rhythms in lower-frequency bands ([Formula: see text], [Formula: see text] and [Formula: see text] rhythms) decreased in the stratum radiatum during HFS. The synchronization of [Formula: see text] rhythm decreased and the synchronization of [Formula: see text] rhythm increased during HFS in the stratum radiatum. These results suggest that axonal HFS could modulate LFP rhythms in the downstream brain areas with a plausible underlying mechanism of partial axonal blockage induced by HFS. The study provides new evidence to support the mechanism of DBS modulating rhythmic activity of neuronal populations.

  20. Fixed-site high-frequency transcutaneous electrical nerve stimulation for treatment of chronic low back and lower extremity pain

    OpenAIRE

    Gozani, Shai

    2016-01-01

    Shai N Gozani NeuroMetrix, Inc., Waltham, MA, USA Objective: The objective of this study was to determine if fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS) is effective in treating chronic low back and lower extremity pain. Background: Transcutaneous electrical nerve stimulation is widely used for treatment of chronic pain. General-purpose transcutaneous electrical nerve stimulation devices are designed for stimulation anywhere on the body and often cannot be ...

  1. Effect of low-frequency deep brain stimulation on sensory thresholds in Parkinson's disease.

    Science.gov (United States)

    Belasen, Abigail; Rizvi, Khizer; Gee, Lucy E; Yeung, Philip; Prusik, Julia; Ramirez-Zamora, Adolfo; Hanspal, Era; Paiva, Priscilla; Durphy, Jennifer; Argoff, Charles E; Pilitsis, Julie G

    2017-02-01

    OBJECTIVE Chronic pain is a major distressing symptom of Parkinson's disease (PD) that is often undertreated. Subthalamic nucleus (STN) deep brain stimulation (DBS) delivers high-frequency stimulation (HFS) to patients with PD and has been effective in pain relief in a subset of these patients. However, up to 74% of patients develop new pain concerns while receiving STN DBS. Here the authors explore whether altering the frequency of STN DBS changes pain perception as measured through quantitative sensory testing (QST). METHODS Using QST, the authors measured thermal and mechanical detection and pain thresholds in 19 patients undergoing DBS via HFS, low-frequency stimulation (LFS), and off conditions in a randomized order. Testing was performed in the region of the body with the most pain and in the lower back in patients without chronic pain. RESULTS In the patients with chronic pain, LFS significantly reduced heat detection thresholds as compared with thresholds following HFS (p = 0.029) and in the off state (p = 0.010). Moreover, LFS resulted in increased detection thresholds for mechanical pressure (p = 0.020) and vibration (p = 0.040) compared with these thresholds following HFS. Neither LFS nor HFS led to changes in other mechanical thresholds. In patients without chronic pain, LFS significantly increased mechanical pain thresholds in response to the 40-g pinprick compared with thresholds following HFS (p = 0.032). CONCLUSIONS Recent literature has suggested that STN LFS can be useful in treating nonmotor symptoms of PD. Here the authors demonstrated that LFS modulates thermal and mechanical detection to a greater extent than HFS. Low-frequency stimulation is an innovative means of modulating chronic pain in PD patients receiving STN DBS. The authors suggest that STN LFS may be a future option to consider when treating Parkinson's patients in whom pain remains the predominant complaint.

  2. Optical parametric amplification and oscillation assisted by low-frequency stimulated emission

    OpenAIRE

    Longhi, Stefano

    2016-01-01

    Optical parametric amplification/oscillation provide a powerful tool for coherent light generation in spectral regions inaccessible to lasers. Parametric gain is based on a frequency {\\it down-conversion} process, and thus it can not be realized for signal waves at a frequency $\\omega_3$ {\\it higher} than the frequency of the pump wave $\\omega_1$. In this work we suggest a route toward the realization of {\\it up-conversion} optical parametric amplification and oscillation, i.e. amplification ...

  3. The Effect of High-Frequency Stimulation on Sensory Thresholds in Chronic Pain Patients.

    Science.gov (United States)

    Youn, Youngwon; Smith, Heather; Morris, Brian; Argoff, Charles; Pilitsis, Julie G

    2015-01-01

    High-frequency stimulation (HFS) has recently gained attention as an alternative to parameters used in traditional spinal cord stimulation (SCS). Because HFS is paresthesia free, the gate theory of pain control as a basis of SCS has been called into question. The mechanism of action of HFS remains unclear. We compare the effects of HFS and traditional SCS on quantitative sensory testing parameters to provide insight into how HFS modulates the nervous system. Using quantitative sensory testing, we measured thermal detection and pain thresholds and mechanical detection and pressure pain thresholds, as well as vibratory detection, in 20 SCS patients off stimulation (OFF), on traditional stimulation (ON) and on HFS in a randomized order. HFS significantly increased the mechanical detection threshold compared to OFF stimulation (p < 0.001) and traditional SCS (p = 0.01). Pressure pain detection and vibratory detection thresholds also significantly increased with HFS compared to ON states (p = 0.04 and p = 0.01, respectively). In addition, HFS significantly decreased 10- and 40-gram pinprick detection compared to OFF states (both p = 0.01). No significant differences between OFF, ON and HFS states were seen in thermal and thermal pain detection. HFS is a new means of modulating chronic pain. The mechanism by which HFS works seems to differ from that of traditional SCS, offering a new platform for innovative advancements in treatment and a greater potential to treat patients by customizing waveforms. © 2015 S. Karger AG, Basel.

  4. Cerebrospinal fluid levels of glial cell-derived neurotrophic factor correlate with spinal cord stimulation frequency in patients with neuropathic pain: a preliminary report.

    Science.gov (United States)

    McCarthy, K F; McCrory, C

    2014-08-01

    Case series. To evaluate relationships between spinal cord stimulation (SCS) parameters and levels of glial cell-derived neurotrophic factor (GDNF). Ambulatory pain clinic of St James's Hospital, Dublin, Ireland. Nine patients with an implanted SCS and Failed Back Surgery Syndrome (FBSS) were administered the Brief Pain Inventory and Short Form (36) Health Survey. Following a lumbar puncture, levels of GDNF in cerebrospinal fluid (CSF) were assayed and correlated with stimulation parameters. Controls were patients with arthritic back pain who were matched for age, gender and SF-36 score. Concentrations of GDNF in CSF are higher in patients with FBSS than controls (P=0.002) and correlate with SCS frequency (P=0.029). Concentrations of GDNF in CSF are higher in neuropathic pain and appear to be related to stimulation frequency. Further work is needed to evaluate this potential relationship, both in neuropathic pain and in other contexts such as locomotor dysfunction.

  5. Frequency-dependent tACS modulation of BOLD signal during rhythmic visual stimulation.

    Science.gov (United States)

    Chai, Yuhui; Sheng, Jingwei; Bandettini, Peter A; Gao, Jia-Hong

    2018-05-01

    Transcranial alternating current stimulation (tACS) has emerged as a promising tool for modulating cortical oscillations. In previous electroencephalogram (EEG) studies, tACS has been found to modulate brain oscillatory activity in a frequency-specific manner. However, the spatial distribution and hemodynamic response for this modulation remains poorly understood. Functional magnetic resonance imaging (fMRI) has the advantage of measuring neuronal activity in regions not only below the tACS electrodes but also across the whole brain with high spatial resolution. Here, we measured fMRI signal while applying tACS to modulate rhythmic visual activity. During fMRI acquisition, tACS at different frequencies (4, 8, 16, and 32 Hz) was applied along with visual flicker stimulation at 8 and 16 Hz. We analyzed the blood-oxygen-level-dependent (BOLD) signal difference between tACS-ON vs tACS-OFF, and different frequency combinations (e.g., 4 Hz tACS, 8 Hz flicker vs 8 Hz tACS, 8 Hz flicker). We observed significant tACS modulation effects on BOLD responses when the tACS frequency matched the visual flicker frequency or the second harmonic frequency. The main effects were predominantly seen in regions that were activated by the visual task and targeted by the tACS current distribution. These findings bridge different scientific domains of tACS research and demonstrate that fMRI could localize the tACS effect on stimulus-induced brain rhythms, which could lead to a new approach for understanding the high-level cognitive process shaped by the ongoing oscillatory signal. © 2018 Wiley Periodicals, Inc.

  6. Low-frequency transcranial magnetic stimulation is beneficial for enhancing synaptic plasticity in the aging brain

    Directory of Open Access Journals (Sweden)

    Zhan-chi Zhang

    2015-01-01

    Full Text Available In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz ameliorates synaptic plasticity and spatial cognitive deficits in learning-impaired mice. However, the mechanisms by which this treatment improves these deficits during normal aging are still unknown. Therefore, the current study investigated the effects of transcranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, synaptophysin and growth-associated protein 43 (both synaptic markers, to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcranial magnetic stimulation with low intensity (110% average resting motor threshold intensity, 1 Hz increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippocampus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this regulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

  7. Low-frequency transcranial magnetic stimulation is beneficial for enhancing synaptic plasticity in the aging brain.

    Science.gov (United States)

    Zhang, Zhan-Chi; Luan, Feng; Xie, Chun-Yan; Geng, Dan-Dan; Wang, Yan-Yong; Ma, Jun

    2015-06-01

    In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz) ameliorates synaptic plasticity and spatial cognitive deficits in learning-impaired mice. However, the mechanisms by which this treatment improves these deficits during normal aging are still unknown. Therefore, the current study investigated the effects of transcranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, synaptophysin and growth-associated protein 43 (both synaptic markers), to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcranial magnetic stimulation with low intensity (110% average resting motor threshold intensity, 1 Hz) increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippocampus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this regulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

  8. Pallidal Deep Brain Stimulation Improves Higher Control of the Oculomotor System in Parkinson's Disease.

    Science.gov (United States)

    Antoniades, Chrystalina A; Rebelo, Pedro; Kennard, Christopher; Aziz, Tipu Z; Green, Alexander L; FitzGerald, James J

    2015-09-23

    The frontal cortex and basal ganglia form a set of parallel but mostly segregated circuits called cortico-basal ganglia loops. The oculomotor loop controls eye movements and can direct relatively simple movements, such as reflexive prosaccades, without external help but needs input from "higher" loops for more complex behaviors. The antisaccade task requires the dorsolateral prefrontal cortex, which is part of the prefrontal loop. Information flows from prefrontal to oculomotor circuits in the striatum, and directional errors in this task can be considered a measure of failure of prefrontal control over the oculomotor loop. The antisaccadic error rate (AER) is increased in Parkinson's disease (PD). Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has no effect on the AER, but a previous case suggested that DBS of the globus pallidus interna (GPi) might. Our aim was to compare the effects of STN DBS and GPi DBS on the AER. We tested eye movements in 14 human DBS patients and 10 controls. GPi DBS substantially reduced the AER, restoring lost higher control over oculomotor function. Interloop information flow involves striatal neurons that receive cortical input and project to pallidum. They are normally silent when quiescent, but in PD they fire randomly, creating noise that may account for the degradation in interloop control. The reduced AER with GPi DBS could be explained by retrograde stimulation of striatopallidal axons with consequent activation of inhibitory collaterals and reduction in background striatal firing rates. This study may help explain aspects of PD pathophysiology and the mechanism of action of GPi DBS. Significance statement: Parkinson's disease causes symptoms including stiffness, slowness of movement, and tremor. Electrical stimulation of specific areas deep in the brain can effectively treat these symptoms, but exactly how is not fully understood. Part of the cause of such symptoms may be impairments in the way information flows

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

    Science.gov (United States)

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

    2018-02-28

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

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

    Directory of Open Access Journals (Sweden)

    Gyu-sik Choi

    2018-01-01

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

  11. Fast oscillations in cortical-striatal networks switch frequency following rewarding events and stimulant drugs.

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    Berke, J D

    2009-09-01

    Oscillations may organize communication between components of large-scale brain networks. Although gamma-band oscillations have been repeatedly observed in cortical-basal ganglia circuits, their functional roles are not yet clear. Here I show that, in behaving rats, distinct frequencies of ventral striatal local field potential oscillations show coherence with different cortical inputs. The approximately 50 Hz gamma oscillations that normally predominate in awake ventral striatum are coherent with piriform cortex, whereas approximately 80-100 Hz high-gamma oscillations are coherent with frontal cortex. Within striatum, entrainment to gamma rhythms is selective to fast-spiking interneurons, with distinct fast-spiking interneuron populations entrained to different gamma frequencies. Administration of the psychomotor stimulant amphetamine or the dopamine agonist apomorphine causes a prolonged decrease in approximately 50 Hz power and increase in approximately 80-100 Hz power. The same frequency switch is observed for shorter epochs spontaneously in awake, undrugged animals and is consistently provoked for reward receipt. Individual striatal neurons can participate in these brief high-gamma bursts with, or without, substantial changes in firing rate. Switching between discrete oscillatory states may allow different modes of information processing during decision-making and reinforcement-based learning, and may also be an important systems-level process by which stimulant drugs affect cognition and behavior.

  12. Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation.

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    Vosskuhl, Johannes; Huster, René J; Herrmann, Christoph S

    2015-01-01

    Working memory (WM) and short-term memory (STM) supposedly rely on the phase-amplitude coupling (PAC) of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual's memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS). To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N = 33) were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG) was measured before stimulation and analyzed with regard to the properties of PAC between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity.

  13. Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation

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    Johannes eVosskuhl

    2015-05-01

    Full Text Available Working memory (WM and short-term memory (STM supposedly rely on the phase-amplitude coupling of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual’s memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS. To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N=33 were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG was measured before stimulation and analyzed with regard to the properties of phase-amplitude coupling between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity.

  14. With medium-chain triglycerides, higher and faster oxygen radical production by stimulated polymorphonuclear leukocytes occurs.

    Science.gov (United States)

    Kruimel, J W; Naber, A H; Curfs, J H; Wenker, M A; Jansen, J B

    2000-01-01

    Parenteral lipid emulsions are suspected of suppressing the immune function. However, study results are contradictory and mainly concern the conventional long-chain triglyceride emulsions. Polymorphonuclear leukocytes were preincubated with parenteral lipid emulsions. The influence of the lipid emulsions on the production of oxygen radicals by these stimulated leukocytes was studied by measuring chemiluminescence. Three different parenteral lipid emulsions were tested: long-chain triglycerides, a physical mixture of medium- and long-chain triglycerides, and structured triglycerides. Structured triglycerides consist of triglycerides where the medium- and long-chain fatty acids are attached to the same glycerol molecule. Stimulated polymorphonuclear leukocytes preincubated with the physical mixture of medium- and long-chain triglycerides showed higher levels of oxygen radicals (p triglycerides or structured triglycerides. Additional studies indicated that differences in results of various lipid emulsions were not caused by differences in emulsifier. The overall production of oxygen radicals was significantly lower after preincubation with the three lipid emulsions compared with controls without lipid emulsion. A physical mixture of medium- and long-chain triglycerides induced faster production of oxygen radicals, resulting in higher levels of oxygen radicals, compared with long-chain triglycerides or structured triglycerides. This can be detrimental in cases where oxygen radicals play either a pathogenic role or a beneficial one, such as when rapid phagocytosis and killing of bacteria is needed. The observed lower production of oxygen radicals by polymorphonuclear leukocytes in the presence of parenteral lipid emulsions may result in immunosuppression by these lipids.

  15. Repetitive low-frequency stimulation reduces epileptiform synchronization in limbic neuronal networks.

    Science.gov (United States)

    D'Arcangelo, G; Panuccio, G; Tancredi, V; Avoli, M

    2005-01-01

    Deep-brain electrical or transcranial magnetic stimulation may represent a therapeutic tool for controlling seizures in patients presenting with epileptic disorders resistant to antiepileptic drugs. In keeping with this clinical evidence, we have reported that repetitive electrical stimuli delivered at approximately 1 Hz in mouse hippocampus-entorhinal cortex (EC) slices depress the EC ability to generate ictal activity induced by the application of 4-aminopyridine (4AP) or Mg(2+)-free medium (Barbarosie, M., Avoli, M., 1997. CA3-driven hippocampal-entorhinal loop controls rather than sustains in vitro limbic seizures. J. Neurosci. 17, 9308-9314.). Here, we confirmed a similar control mechanism in rat brain slices analyzed with field potential recordings during 4AP (50 microM) treatment. In addition, we used intrinsic optical signal (IOS) recordings to quantify the intensity and spatial characteristics of this inhibitory influence. IOSs reflect the changes in light transmittance throughout the entire extent of the slice, and are thus reliable markers of limbic network epileptiform synchronization. First, we found that in the presence of 4AP, the IOS increases, induced by a train of electrical stimuli (10 Hz for 1 s) or by recurrent, single-shock stimulation delivered at 0.05 Hz in the deep EC layers, are reduced in intensity and area size by low-frequency (1 Hz), repetitive stimulation of the subiculum; these effects were observed in all limbic areas contained in the slice. Second, by testing the effects induced by repetitive subicular stimulation at 0.2-10 Hz, we identified maximal efficacy when repetitive stimuli are delivered at 1 Hz. Finally, we discovered that similar, but slightly less pronounced, inhibitory effects occur when repetitive stimuli at 1 Hz are delivered in the EC, suggesting that the reduction of IOSs seen during repetitive stimulation is pathway dependent as well as activity dependent. Thus, the activation of limbic networks at low frequency

  16. A current drive by using the fast wave in frequency range higher than two timeslower hybrid resonance frequency on tokamaks

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    Kim Sun Ho

    2017-01-01

    Full Text Available An efficient current drive scheme in central or off-axis region is required for the steady state operation of tokamak fusion reactors. The current drive by using the fast wave in frequency range higher than two times lower hybrid resonance (w>2wlh could be such a scheme in high density, high temperature reactor-grade tokamak plasmas. First, it has relatively higher parallel electric field to the magnetic field favorable to the current generation, compared to fast waves in other frequency range. Second, it can deeply penetrate into high density plasmas compared to the slow wave in the same frequency range. Third, parasitic coupling to the slow wave can contribute also to the current drive avoiding parametric instability, thermal mode conversion and ion heating occured in the frequency range w<2wlh. In this study, the propagation boundary, accessibility, and the energy flow of the fast wave are given via cold dispersion relation and group velocity. The power absorption and current drive efficiency are discussed qualitatively through the hot dispersion relation and the polarization. Finally, those characteristics are confirmed with ray tracing code GENRAY for the KSTAR plasmas.

  17. Modulation of N400 in Chronic Non-Fluent Aphasia Using Low Frequency Repetitive Transcranial Magnetic Stimulation (rTMS)

    Science.gov (United States)

    Barwood, Caroline H. S.; Murdoch, Bruce E.; Whelan, Brooke-Mai; Lloyd, David; Riek, Stephan; O'Sullivan, John D.; Coulthard, Alan; Wong, Andrew

    2011-01-01

    Low frequency Repetitive Transcranial Magnetic Stimulation (rTMS) has previously been applied to language homologues in non-fluent populations of persons with aphasia yielding significant improvements in behavioral language function up to 43 months post stimulation. The present study aimed to investigate the electrophysiological correlates…

  18. Dependences of the geometrical parameters of cell community on stimulation voltage and frequency in chick embryonic cardiomyocytes

    Science.gov (United States)

    Fujii, Koki; Nomura, Fumimasa; Kaneko, Tomoyuki

    2018-03-01

    To investigate the optimal conditions for electrical stimulation, communities of lined-up chick embryonic cardiomyocytes were evaluated in terms of their threshold voltage for pacing (PVMin) and the half-maximum paced frequency (PF50), with a focus on the following factors: (1) the orientation of the major axis of cell communities to the electric field (EF) direction as the external factor; (2) the number of cells in a cell community, the length of the cell community, and the mean length of cells comprising the community as the internal factors. Firstly, PVMin decreased with increasing length of the cell network oriented parallel to the EF. PVMin was approximately 0.041 ± 0.025 V/mm when the community was sufficiently long. On the other hand, PVMin in the orthogonal orientation was constant at 1.7 ± 0.047 V/mm with no dependence on the length of the cell network. Secondly, we found that PF50 increased with increasing length of the cell network or the number of cells in the network; the PF50 values were 2.03 ± 0.05 and 3.39 ± 0.05 Hz when the respective cell network lengths were 100 µm (n = 43) and more than 300 µm (n = 6) and the cells were oriented parallel to the EF. These findings indicate that it is important to suppress ventricular fibrillation with minimal efficient stimulation by considering the EF direction with respect to the orientation of cardiomyocytes. Furthermore, expanded cells showed the loss of ability to respond to stimulation at higher frequencies. Cardiomyocytes combined with seeded fibroblasts as a cell network at a low density are a possible model of a ventricular remodeling heart.

  19. Effect of low frequency transcutaneous magnetic stimulation on sensory and motor transmission.

    Science.gov (United States)

    Leung, Albert; Shukla, Shivshil; Lee, Jacquelyn; Metzger-Smith, Valerie; He, Yifan; Chen, Jeffrey; Golshan, Shahrokh

    2015-09-01

    Peripheral nerve injury diminishes fast conducting large myelinated afferent fibers transmission but enhances smaller pain transmitting fibers firing. This aberrant afferent neuronal behavior contributes to development of chronic post-traumatic peripheral neuropathic pain (PTP-NP). Non-invasive dynamic magnetic flux stimulation has been implicated in treating PTP-NP, a condition currently not adequately addressed by other therapies including transcutaneous electrical nerve stimulation (TENS). The current study assessed the effect of low frequency transcutaneous magnetic stimulation (LFTMS) on peripheral sensory thresholds, nerve conduction properties, and TENS induced fast afferent slowing effect as measured by motor and sensory conduction studies in the ulnar nerve. Results indicated sham LFTMS with TENS (Sham + TENS) significantly (P = 0.02 and 0.007, respectively) reduces sensory conduction velocity (CV) and increases sensory onset latency (OL), and motor peak latency (PL) whereas, real LFTMS with TENS (Real + TENS) reverses effects of TENS on sensory CV and OL, and significantly (P = 0.036) increases the sensory PL. LFTMS alone significantly (P sensory PL and onset-to-peak latency. LFTMS appears to reverse TENS slowing effect on fast conducting fibers and casts a selective peripheral modulatory effect on slow conducting pain afferent fibers. © 2015 Wiley Periodicals, Inc.

  20. High Frequency Deep Brain Stimulation and Neural Rhythms in Parkinson's Disease.

    Science.gov (United States)

    Blumenfeld, Zack; Brontë-Stewart, Helen

    2015-12-01

    High frequency (HF) deep brain stimulation (DBS) is an established therapy for the treatment of Parkinson's disease (PD). It effectively treats the cardinal motor signs of PD, including tremor, bradykinesia, and rigidity. The most common neural target is the subthalamic nucleus, located within the basal ganglia, the region most acutely affected by PD pathology. Using chronically-implanted DBS electrodes, researchers have been able to record underlying neural rhythms from several nodes in the PD network as well as perturb it using DBS to measure the ensuing neural and behavioral effects, both acutely and over time. In this review, we provide an overview of the PD neural network, focusing on the pathophysiological signals that have been recorded from PD patients as well as the mechanisms underlying the therapeutic benefits of HF DBS. We then discuss evidence for the relationship between specific neural oscillations and symptoms of PD, including the aberrant relationships potentially underlying functional connectivity in PD as well as the use of different frequencies of stimulation to more specifically target certain symptoms. Finally, we briefly describe several current areas of investigation and how the ability to record neural data in ecologically-valid settings may allow researchers to explore the relationship between brain and behavior in an unprecedented manner, culminating in the future automation of neurostimulation therapy for the treatment of a variety of neuropsychiatric diseases.

  1. Subthalamic nucleus high-frequency stimulation restores altered electrophysiological properties of cortical neurons in parkinsonian rat.

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    Bertrand Degos

    Full Text Available Electrophysiological recordings performed in parkinsonian patients and animal models have confirmed the occurrence of alterations in firing rate and pattern of basal ganglia neurons, but the outcome of these changes in thalamo-cortical networks remains unclear. Using rats rendered parkinsonian, we investigated, at a cellular level in vivo, the electrophysiological changes induced in the pyramidal cells of the motor cortex by the dopaminergic transmission interruption and further characterized the impact of high-frequency electrical stimulation of the subthalamic nucleus, a procedure alleviating parkinsonian symptoms. We provided evidence that a lesion restricted to the substantia nigra pars compacta resulted in a marked increase in the mean firing rate and bursting pattern of pyramidal neurons of the motor cortex. These alterations were underlain by changes of the electrical membranes properties of pyramidal cells including depolarized resting membrane potential and increased input resistance. The modifications induced by the dopaminergic loss were more pronounced in cortico-striatal than in cortico-subthalamic neurons. Furthermore, subthalamic nucleus high-frequency stimulation applied at parameters alleviating parkinsonian signs regularized the firing pattern of pyramidal cells and restored their electrical membrane properties.

  2. Anti-fatigue effect of percutaneous stimulation of the hepatic region by mid-frequency pulse current in different diadynamic cycles in soldiers with exercise-induced fatigue

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    Peng-yi DAI

    2012-01-01

    Full Text Available Objective  To investigate the anti-fatigue effect of percutaneous stimulation of the hepatic region with the mid-frequency pulse current in different diadynamic cycles in exercise-induced fatigued soldiers. Methods  One hundred twenty healthy PLA recruits who did not have physical exercise were randomly divided into four groups with thirty ones in each: control, stimulation group A, stimulation group B, and stimulation group C. All the subjects of four groups were ordered intensive training (exercise from Monday to Saturday, with rest on Sunday for five weeks to establish the exercise-induced fatigue model. Each day after the exercise, the recruits of stimulation groups A, B, and C were treated immediately with mid-frequency (1204Hz, current intensity ≤80mA stimulation to the hepatic region with diadynamic cycles of 0.5, 1, and 2 seconds, respectively. No pulse current stimulation was given in the control group. Venous blood was collected before breakfast on Sundays to measure the fasting plasma glucose (FPG and blood lactate (LAC contents, and liver function was determined by determination of alanine aminotransferase (ALT, aspartate aminotransferase (AST, and lactate dehydrogenase (LDH. The 3000-m running performance of the recruits in each group was recorded on the same day. Results  There was no significant difference between the four groups in terms of the FPG level at the end of the first week (P>0.05. At the end of the third and fifth weeks, the FPG level was significantly higher in the three stimulation groups than in the control group (PPP>0.05. At the end of the first, third, and fifth weeks, the ALT, AST, LDH, and LAC levels were significantly lower in every stimulation group than in the control group (PPPPP>0.05. At the end of the first week, there was no significant difference in 3000-m running performance (P>0.05 between the 4 groups. At the end of the third and fifth weeks, the 3000-m running performance was significantly

  3. Low-frequency stimulation cancels the high-frequency-induced long-lasting effects in the rat medial vestibular nuclei.

    Science.gov (United States)

    Grassi, S; Pettorossi, V E; Zampolini, M

    1996-05-15

    In rat brainstem slices, we investigated the effects of low-frequency stimulation (LFS) of the primary vestibular afferents on the amplitude of the field potentials evoked in the medial vestibular nuclei (MVN). LFS induced long-term effects, the sign of which depended on whether the vestibular neurons were previously conditioned by HFS. In unconditioned slices, LFS evoked modifications of the responses that were similar to those observed after HFS but had a smaller extension. In fact, LFS caused long-lasting potentiation of the N1 wave in the MVN ventral portion (Vp) and long-lasting depression of the N2 wave in the MVN dorsal portion (Dp), whereas it provoked small and variable effects on the N1 wave. By contrast, when the synaptic transmission was already conditioned, LFS influenced the synaptic responses oppositely, reducing or annulling the HFS long-term effects. This phenomenon was specifically induced by LFS, because HFS was not able to cause it. The involvement of NMDA receptors in mediating the LFS long-term effects was supported by the fact that AP-5 prevented their induction. In addition, the annulment of HFS long-term effects by LFS was also demonstrated by the shift in the latency of the evoked unitary potentials after LFS. In conclusion, we suggest that the reduction of the previously induced conditioning could represent a cancellation mechanism, useful to quickly adapt the vestibular system to continuous different needs and to avoid saturation.

  4. [Clinical research of post-stroke insomnia treated with low-frequency electric stimulation at acupoints in the patients].

    Science.gov (United States)

    Tang, Lei; You, Fei; Ma, Chao-Yang

    2014-08-01

    To compare the difference in the clinical efficacy on post-stroke insomnia between the low-frequency electric stimulation at the acupoints and the conventional western medication. One hundred and twenty patients of post-stroke insomnia were randomized into a low-frequency electric stimulation group, a medication group and a placebo group, 40 cases in each one. In the low-frequency electric stimulation group, the low-frequency electric-pulsing apparatus was used at Dazhui (GV 14) and Shenshu (BL 23), once a day; the treatment of 15 days made one session and 2 sessions were required. In the medication group, estazolam was taken orally, 1 mg each time. In the placebo group, starch capsules were taken orally, 1 capsule each time. All the drugs were taken before sleep every night, continuously for 15 days as one session, and 2 sessions were required. PSQI changes and clinical efficacy were observed before and after treatment in each group. Pitlsburgh sleep quality index (PSQI) score was reduced in every group after treatment (all P low-frequency electric stimulation group and medication group, the score was reduced much more significantly as compared with the placebo group (both P low-frequency electric stimulation group, medication group and placebo group separately. The efficacy in the low-frequency electric stimulation group and medication group was better apparently than that in the placebo group (both P low-frequency electric stimulation at the acupoints effectively and safely treats post-stroke insomnia and the efficacy of it is similar to that of estazolam.

  5. Sacral Nerve Stimulation For Urinary Urge Incontinence, Urgency-Frequency, Urinary Retention, and Fecal Incontinence

    Science.gov (United States)

    2005-01-01

    Executive Summary Objective The aim of this review was to assess the effectiveness, safety, and cost of sacral nerve stimulation (SNS) to treat urinary urge incontinence, urgency-frequency, urinary retention, and fecal incontinence. Background: Condition and Target Population Urinary urge incontinence, urgency-frequency, urinary retention, and fecal incontinence are prevalent, yet rarely discussed, conditions. They are rarely discussed because patients may be uncomfortable disclosing their symptoms to a health professional or may be unaware that there are treatment options for these conditions. Briefly, urge incontinence is an involuntary loss of urine upon a sudden urge. Urgency-frequency is an uncontrollable urge to void, which results in frequent, small-volume voids. People with urgency-frequency may or may not also experience chronic pelvic pain. Urinary retention refers to the inability to void despite having the urge to void. It can be caused by a hypocontractile detrusor (weak or no bladder muscle contraction) or obstruction due to urethral overactivity. Fecal incontinence is a loss of voluntary bowel control. The prevalence of urge incontinence, urgency-frequency, and urinary retention in the general population is 3.3% to 8.2%, and the prevalence of fecal incontinence is 1.4% to 1.9%. About three-quarters of these people will be successfully treated by behaviour and/or drug therapy. For those who do not respond to these therapies, the options for treatment are management with diapers or pads, or surgery. The surgical procedures are generally quite invasive, permanent, and are associated with complications. Pads and/or diapers are used throughout the course of treatment as different therapies are tried. Patients who respond successfully to treatment may still require pads or diapers, but to a lesser extent. The Technology Being Reviewed: Sacral Nerve Stimulation Sacral nerve stimulation is a procedure where a small device attached to an electrode is

  6. 50 Hz hippocampal stimulation in refractory epilepsy: Higher level of basal glutamate predicts greater release of glutamate.

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    Cavus, Idil; Widi, Gabriel A; Duckrow, Robert B; Zaveri, Hitten; Kennard, Jeremy T; Krystal, John; Spencer, Dennis D

    2016-02-01

    The effect of electrical stimulation on brain glutamate release in humans is unknown. Glutamate is elevated at baseline in the epileptogenic hippocampus of patients with refractory epilepsy, and increases during spontaneous seizures. We examined the effect of 50 Hz stimulation on glutamate release and its relationship to interictal levels in the hippocampus of patients with epilepsy. In addition, we measured basal and stimulated glutamate levels in a subset of these patients where stimulation elicited a seizure. Subjects (n = 10) were patients with medically refractory epilepsy who were undergoing intracranial electroencephalography (EEG) evaluation in an epilepsy monitoring unit. Electrical stimulation (50 Hz) was delivered through implanted hippocampal electrodes (n = 11), and microdialysate samples were collected every 2 min. Basal glutamate, changes in glutamate efflux with stimulation, and the relationships between peak stimulation-associated glutamate concentrations, basal zero-flow levels, and stimulated seizures were examined. Stimulation of epileptic hippocampi in patients with refractory epilepsy caused increases in glutamate efflux (p = 0.005, n = 10), and 4 of ten patients experienced brief stimulated seizures. Stimulation-induced increases in glutamate were not observed during the evoked seizures, but rather were related to the elevation in interictal basal glutamate (R(2) = 0.81, p = 0.001). The evoked-seizure group had lower basal glutamate levels than the no-seizure group (p = 0.04), with no stimulation-induced change in glutamate efflux (p = 0.47, n = 4). Conversely, increased glutamate was observed following stimulation in the no-seizure group (p = 0.005, n = 7). Subjects with an atrophic hippocampus had higher basal glutamate levels (p = 0.03, n = 7) and higher stimulation-induced glutamate efflux. Electrical stimulation of the epileptic hippocampus either increased extracellular glutamate efflux or induced seizures. The magnitude of stimulated

  7. Masking release with changing fundamental frequency: Electric acoustic stimulation resembles normal hearing subjects.

    Science.gov (United States)

    Auinger, Alice Barbara; Riss, Dominik; Liepins, Rudolfs; Rader, Tobias; Keck, Tilman; Keintzel, Thomas; Kaider, Alexandra; Baumgartner, Wolf-Dieter; Gstoettner, Wolfgang; Arnoldner, Christoph

    2017-07-01

    It has been shown that patients with electric acoustic stimulation (EAS) perform better in noisy environments than patients with a cochlear implant (CI). One reason for this could be the preserved access to acoustic low-frequency cues including the fundamental frequency (F0). Therefore, our primary aim was to investigate whether users of EAS experience a release from masking with increasing F0 difference between target talker and masking talker. The study comprised 29 patients and consisted of three groups of subjects: EAS users, CI users and normal-hearing listeners (NH). All CI and EAS users were implanted with a MED-EL cochlear implant and had at least 12 months of experience with the implant. Speech perception was assessed with the Oldenburg sentence test (OlSa) using one sentence from the test corpus as speech masker. The F0 in this masking sentence was shifted upwards by 4, 8, or 12 semitones. For each of these masker conditions the speech reception threshold (SRT) was assessed by adaptively varying the masker level while presenting the target sentences at a fixed level. A statistically significant improvement in speech perception was found for increasing difference in F0 between target sentence and masker sentence in EAS users (p = 0.038) and in NH listeners (p = 0.003). In CI users (classic CI or EAS users with electrical stimulation only) speech perception was independent from differences in F0 between target and masker. A release from masking with increasing difference in F0 between target and masking speech was only observed in listeners and configurations in which the low-frequency region was presented acoustically. Thus, the speech information contained in the low frequencies seems to be crucial for allowing listeners to separate multiple sources. By combining acoustic and electric information, EAS users even manage tasks as complicated as segregating the audio streams from multiple talkers. Preserving the natural code, like fine-structure cues in

  8. The application of low frequency repetitive transcranial magnetic stimulation in rehabilitation of Parkinson's disease patients

    Directory of Open Access Journals (Sweden)

    WU Zhuo-hua

    2013-07-01

    Full Text Available Objective To explore the application value of low frequency repetitive transcranial magnetic stimulation (rTMS in Parkinson's disease (PD patients and electrophysiological research. Methods Fifty-six PD patients treated in the Department of Neurology of our hospital from September 2010 to September 2012 were randomly divided into 2 groups, group A (N = 28 and group B (N = 28. Patients in group A were given conventional drug treatment and rehabilitation training, while patients in group B were given low frequency rTMS on the basis of conventional drug treatment and rehabilitation training. After 3 weeks, the scores of Unified Parkinson's Disease Rating Scale (UPDRS, resting threshold (RT, cortical latent period, nerve root latent period, central motor conduction time (CMCT and the incidence of adverse reactions were compared between 2 groups. Results After intervention, the emotion, ability of daily living and motor function of patients in group B was obviously improved, and the scores of UPDRS in group B were significantly lower than that in group A (P 0.05. Conclusion The effect of low frequency rTMS in the treatment for PD is evident, safe and reliable, and with less adverse reaction. It can be used as a noninvasive physical treatment measure for PD.

  9. Effect of ischemia and cooling on the response to high frequency stimulation in rat tail nerves

    DEFF Research Database (Denmark)

    Andersen, H.; Nielsen, J.F.; Sørensen, B.

    2000-01-01

    In normal rat tail nerves the effect of temperature and ischemia on the response to long-term high frequency stimulation (HFS) (143 Hz) was studied. The effect of temperature was studied in two consecutive tests at 14 degrees C and 35 degrees C. Prior to the HFS the peak-to-peak amplitude (PP......-amp) of the compound nerve action potential was 139 +/- 20 microV (mean +/- SD) and 127 +/- 37 microV at 35 degrees C and 14 degrees C, respectively (NS). After 15 min of HFS the PP-amp was reduced to 45.3 +/- 20.5% of baseline level at 14 degrees C as compared with 80.8 +/- 10.2% at 35 degrees C (p

  10. Effective treatment of narcolepsy-like symptoms with high-frequency repetitive transcranial magnetic stimulation

    Science.gov (United States)

    Lai, Jian-bo; Han, Mao-mao; Xu, Yi; Hu, Shao-hua

    2017-01-01

    Abstract Rationale: Narcolepsy is a rare sleep disorder with disrupted sleep-architecture. Clinical management of narcolepsy lies dominantly on symptom-driven pharmacotherapy. The treatment role of repetitive transcranial magnetic stimulation (rTMS) for narcolepsy remains unexplored. Patient concerns: In this paper, we present a case of a 14-year-old young girl with excessive daytime sleepiness (EDS), cataplexy and hypnagogic hallucinations. Diagnoses: After excluding other possible medical conditions, this patient was primarily diagnosed with narcolepsy. Interventions: The patient received 25 sessions of high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC). Outcomes: The symptoms of EDS and cataplexy significantly improved after rTMS treatment. Meanwhile, her score in the Epworth sleep scale (ESS) also remarkably decreased. Lessons: This case indicates that rTMS may be selected as a safe and effective alternative strategy for treating narcolepsy-like symptoms. Well-designed researches are warranted in future investigations on this topic. PMID:29145290

  11. Tunable KTA Stokes laser based on stimulated polariton scattering and its intracavity frequency doubling.

    Science.gov (United States)

    Zang, Jie; Cong, Zhenhua; Chen, Xiaohan; Zhang, Xingyu; Qin, Zengguang; Liu, Zhaojun; Lu, Jianren; Wu, Dong; Fu, Qiang; Jiang, Shiqi; Zhang, Shaojun

    2016-04-04

    This paper presents the tunable Stokes laser characteristics of KTiOAsO4 (KTA) crystal based on stimulated polariton scattering (SPS). When the pumping laser wavelength is 1064.2 nm, the KTA Stokes wave can be discontinuously tuned from 1077.9 to 1088.4 nm with four gaps from 1079.0 to 1080.1 nm, from 1080.8 to 1082.8 nm, from 1083.6 to 1085.5 nm, and from 1085.8 to 1086.8 nm. When a frequency doubling crystal LiB3O5 (LBO) is inserted into the Stokes laser cavity, the frequency-doubled wave can be discontinuously tuned from 539.0 to 539.5 nm, from 540.1 to 540.4 nm, from 541.3 to 541.8 nm, from 542.7 to 542.9 nm and from 543.4 to 544.2 nm. With a pumping pulse energy of 130.0 mJ and an output coupler reflectivity of about 30%, the obtained maximum Stokes laser pulse energy at 1078.6 nm is 33.9 mJ and the obtained maximum frequency-doubled laser pulse energy at 543.8 nm is 15.7 mJ. By using the most probably coupled transverse optical modes obtained from the literature, the polariton refractive indexes, and the simplified polariton Sellmeier equations, the polariton dispersion curve is obtained. The formation of the Stokes frequency gaps is explained.

  12. Stimulated Emission Computed Tomography (NSECT) images enhancement using a linear filter in the frequency domain

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Rodrigo S.S.; Tardelli, Tiago C.; Yoriyaz, Helio, E-mail: hyoriyaz@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Jackowski, Marcel P., E-mail: mjack@ime.usp.b [University of Sao Paulo (USP), SP (Brazil). Dept. of Computer Science

    2011-07-01

    In recent years, a new technique for in vivo spectrographic imaging of stable isotopes was presented as Neutron Stimulated Emission Computed Tomography (NSECT). In this technique, a fast neutrons beam stimulates stable nuclei in a sample, which emit characteristic gamma radiation. The photon energy is unique and is used to identify the emitting nuclei. The emitted gamma energy spectra can be used for reconstruction of the target tissue image and for determination of the tissue elemental composition. Due to the stochastic nature of photon emission process by irradiated tissue, one of the most suitable algorithms for tomographic reconstruction is the Expectation-Maximization (E-M) algorithm, once on its formulation are considered simultaneously the probabilities of photons emission and detection. However, a disadvantage of this algorithm is the introduction of noise in the reconstructed image as the number of iterations increases. This increase can be caused either by features of the algorithm itself or by the low sampling rate of projections used for tomographic reconstruction. In this work, a linear filter in the frequency domain was used in order to improve the quality of the reconstructed images. (author)

  13. Stimulated Emission Computed Tomography (NSECT) images enhancement using a linear filter in the frequency domain

    International Nuclear Information System (INIS)

    Viana, Rodrigo S.S.; Tardelli, Tiago C.; Yoriyaz, Helio; Jackowski, Marcel P.

    2011-01-01

    In recent years, a new technique for in vivo spectrographic imaging of stable isotopes was presented as Neutron Stimulated Emission Computed Tomography (NSECT). In this technique, a fast neutrons beam stimulates stable nuclei in a sample, which emit characteristic gamma radiation. The photon energy is unique and is used to identify the emitting nuclei. The emitted gamma energy spectra can be used for reconstruction of the target tissue image and for determination of the tissue elemental composition. Due to the stochastic nature of photon emission process by irradiated tissue, one of the most suitable algorithms for tomographic reconstruction is the Expectation-Maximization (E-M) algorithm, once on its formulation are considered simultaneously the probabilities of photons emission and detection. However, a disadvantage of this algorithm is the introduction of noise in the reconstructed image as the number of iterations increases. This increase can be caused either by features of the algorithm itself or by the low sampling rate of projections used for tomographic reconstruction. In this work, a linear filter in the frequency domain was used in order to improve the quality of the reconstructed images. (author)

  14. Retinal ganglion cells: mechanisms underlying depolarization block and differential responses to high frequency electrical stimulation of ON and OFF cells

    Science.gov (United States)

    Kameneva, T.; Maturana, M. I.; Hadjinicolaou, A. E.; Cloherty, S. L.; Ibbotson, M. R.; Grayden, D. B.; Burkitt, A. N.; Meffin, H.

    2016-02-01

    Objective. ON and OFF retinal ganglion cells (RGCs) are known to have non-monotonic responses to increasing amplitudes of high frequency (2 kHz) biphasic electrical stimulation. That is, an increase in stimulation amplitude causes an increase in the cell’s spike rate up to a peak value above which further increases in stimulation amplitude cause the cell to decrease its activity. The peak response for ON and OFF cells occurs at different stimulation amplitudes, which allows differential stimulation of these functional cell types. In this study, we investigate the mechanisms underlying the non-monotonic responses of ON and OFF brisk-transient RGCs and the mechanisms underlying their differential responses. Approach. Using in vitro patch-clamp recordings from rat RGCs, together with simulations of single and multiple compartment Hodgkin-Huxley models, we show that the non-monotonic response to increasing amplitudes of stimulation is due to depolarization block, a change in the membrane potential that prevents the cell from generating action potentials. Main results. We show that the onset for depolarization block depends on the amplitude and frequency of stimulation and reveal the biophysical mechanisms that lead to depolarization block during high frequency stimulation. Our results indicate that differences in transmembrane potassium conductance lead to shifts of the stimulus currents that generate peak spike rates, suggesting that the differential responses of ON and OFF cells may be due to differences in the expression of this current type. We also show that the length of the axon’s high sodium channel band (SOCB) affects non-monotonic responses and the stimulation amplitude that leads to the peak spike rate, suggesting that the length of the SOCB is shorter in ON cells. Significance. This may have important implications for stimulation strategies in visual prostheses.

  15. Real-time CARS imaging reveals a calpain-dependent pathway for paranodal myelin retraction during high-frequency stimulation.

    Directory of Open Access Journals (Sweden)

    Terry B Huff

    2011-03-01

    Full Text Available High-frequency electrical stimulation is becoming a promising therapy for neurological disorders, however the response of the central nervous system to stimulation remains poorly understood. The current work investigates the response of myelin to electrical stimulation by laser-scanning coherent anti-Stokes Raman scattering (CARS imaging of myelin in live spinal tissues in real time. Paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation. Retraction was seen to begin minutes after the onset of stimulation and continue for up to 10 min after stimulation was ceased, but was found to reverse after a 2 h recovery period. The myelin retraction resulted in exposure of Kv 1.2 potassium channels visualized by immunofluorescence. Accordingly, treating the stimulated tissue with a potassium channel blocker, 4-aminopyridine, led to the appearance of a shoulder peak in the compound action potential curve. Label-free CARS imaging of myelin coupled with multiphoton fluorescence imaging of immuno-labeled proteins at the nodes of Ranvier revealed that high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down.

  16. Boxcar detection for high-frequency modulation in stimulated Raman scattering microscopy

    Science.gov (United States)

    Fimpel, P.; Riek, C.; Ebner, L.; Leitenstorfer, A.; Brida, D.; Zumbusch, A.

    2018-04-01

    Stimulated Raman scattering (SRS) microscopy is an important non-linear optical technique for the investigation of unlabeled samples. The SRS signal manifests itself as a small intensity exchange between the laser pulses involved in coherent excitation of Raman modes. Usually, high-frequency modulation is applied in one pulse train, and the signal is then detected on the other pulse train via lock-in amplification. While allowing shot-noise limited detection sensitivity, lock-in detection, which corresponds to filtering the signal in the frequency domain, is not the most efficient way of using the excitation light. In this manuscript, we show that boxcar averaging, which is equivalent to temporal filtering, is better suited for the detection of low-duty-cycle signals as encountered in SRS microscopy. We demonstrate that by employing suitable gating windows, the signal-to-noise ratios achievable with lock-in detection can be realized in shorter time with boxcar averaging. Therefore, high-quality images are recorded at a faster rate and lower irradiance which is an important factor, e.g., for minimizing degradation of biological samples.

  17. Multisensory Stimulation to Improve Low- and Higher-Level Sensory Deficits after Stroke : A Systematic Review

    NARCIS (Netherlands)

    Tinga, A.M.; Visser-Meily, Johanna M a; van der Smagt, M.J.; van der Stigchel, S.; van Ee, R.; Nijboer, T.C.W.

    The aim of this systematic review was to integrate and assess evidence for the effectiveness of multisensory stimulation (i.e., stimulating at least two of the following sensory systems: visual, auditory, and somatosensory) as a possible rehabilitation method after stroke. Evidence was considered

  18. Suppression of motor cortical excitability in anesthetized rats by low frequency repetitive transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Paul A Muller

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a widely-used method for modulating cortical excitability in humans, by mechanisms thought to involve use-dependent synaptic plasticity. For example, when low frequency rTMS (LF rTMS is applied over the motor cortex, in humans, it predictably leads to a suppression of the motor evoked potential (MEP, presumably reflecting long-term depression (LTD -like mechanisms. Yet how closely such rTMS effects actually match LTD is unknown. We therefore sought to (1 reproduce cortico-spinal depression by LF rTMS in rats, (2 establish a reliable animal model for rTMS effects that may enable mechanistic studies, and (3 test whether LTD-like properties are evident in the rat LF rTMS setup. Lateralized MEPs were obtained from anesthetized Long-Evans rats. To test frequency-dependence of LF rTMS, rats underwent rTMS at one of three frequencies, 0.25, 0.5, or 1 Hz. We next tested the dependence of rTMS effects on N-methyl-D-aspartate glutamate receptor (NMDAR, by application of two NMDAR antagonists. We find that 1 Hz rTMS preferentially depresses unilateral MEP in rats, and that this LTD-like effect is blocked by NMDAR antagonists. These are the first electrophysiological data showing depression of cortical excitability following LF rTMS in rats, and the first to demonstrate dependence of this form of cortical plasticity on the NMDAR. We also note that our report is the first to show that the capacity for LTD-type cortical suppression by rTMS is present under barbiturate anesthesia, suggesting that future neuromodulatory rTMS applications under anesthesia may be considered.

  19. Reducing Undue Conservatism in "Higher Frequency" Structural Design Loads in Aerospace Components

    Science.gov (United States)

    Knight, J. Brent

    2012-01-01

    This study is intended to investigate the frequency dependency of significant strain due to vibratory loads in aerospace vehicle components. The notion that "higher frequency" dynamic loads applied as static loads is inherently conservative is perceived as widely accepted. This effort is focused on demonstrating that principle and attempting to evolve methods to capitalize on it to mitigate undue conservatism. It has been suggested that observations of higher frequency modes that resulted in very low corresponding strain did so due to those modes not being significant. Two avionics boxes, one with its first significant mode at 341 Hz and the other at 857 Hz, were attached to a flat panel installed on a curved orthogrid panel which was driven acoustically in tests performed at NASA/MSFC. Strain and acceleration were measured at select locations on each of the boxes. When possible, strain gage rosettes and accelerometers were installed on either side of a given structural member so that measured strain and acceleration data would directly correspond to one another. Ultimately, a frequency above which vibratory loads can be disregarded for purposes of static structural analyses and sizing of typical robust aerospace components is sought.

  20. Species With Greater Aerial Maneuverability Have Higher Frequency of Collisions With Aircraft: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Esteban Fernández-Juricic

    2018-03-01

    Full Text Available Antipredator responses may appear unsuccessful when animals are exposed to approaching vehicles, often resulting in mortality. Recent studies have addressed whether certain biological traits are associated with variation in collision risk with cars, but not with higher speed-vehicles like aircraft. Our goal was to establish the association between different species traits (i.e., body mass, eye size, brain size, wing loading, wing aspect ratio and the frequency of bird collisions with aircraft (hereafter, bird strikes using a comparative approach controlling for the effects of shared ancestry. We proposed directional predictions as to how each of the species traits would affect the frequency of bird strikes. Considering 39 bird species with all traits represented, the model containing wing loading had the best fit to account for the variance in bird strikes across species. In another model with 54 species exploring the fit to different polynomial models but considering only wing loading, we found that wing loading was negatively and linearly associated with the frequency of bird strikes. Counterintuitively, species with lower wing loading (hence, greater maneuverability had a higher frequency of bird strikes. We discuss potential non-mutually exclusive explanations (e.g., high wing loading species fly faster, thus gaining some extra time to avoid the aircraft flight path; high wing loading species are hazed more intensively at airports, which could lower collisions, etc.. Ultimately, our findings uncovered that species with low wing loading get struck at a higher rate at airports, which reduces the safety risk for humans because these species tend not to cause damaging strikes, but the ecological consequences of their potentially higher local mortality are unknown.

  1. Skin complications in deep brain stimulation for Parkinson's disease: frequency, time course, and risk factors.

    Science.gov (United States)

    Sixel-Döring, Friederike; Trenkwalder, Claudia; Kappus, Christoph; Hellwig, Dieter

    2010-02-01

    Deep brain stimulation (DBS) has been recognized as an efficacious treatment for movement disorders. Its beneficial effects however may be lost due to skin complications such as erosions or infections over the implanted foreign material. We sought to document skin complications in the entire Parkinson's disease patient population who received a DBS system at the Marburg/Kassel implantation centre since the start of our DBS program in January 2002 to analyze frequency, time course, and possible risk factors. We investigated 85 consecutive patients with Parkinson's disease (PD) from a single center/single surgeon DBS series for the occurrence of skin complications and analyzed localization, time course, and possible risk factors. Mean follow-up was 3 years (range 1-7 years). In total, 21/85 patients (24.7%) suffered a total of 30 single skin complications. Sixty percent of all incidents occurred within the first post-operative year. Forty percent of all incidents occurred later than the first year following primary implantation. Complications involved the burr hole cap in 37%, the course of the cables in 33%, and the impulse generator (IPG) site in 30%. Six of 21 patients suffered recurring skin complications. Eight patients permanently lost their DBS system. Factor analysis for age, gender, disease duration, disease severity, the incidence of hypertension or diabetes as well as a 2-day period with externalized electrodes for continuous test stimulation did not have any statistically significant impact on skin complications. We conclude that (1) PD patients have a risk for skin complications after DBS as long as the system remains in situ and (2) there are at present no identifiable risk factors for skin complications after DBS, other than PD itself.

  2. High frequency deep brain stimulation attenuates subthalamic and cortical rhythms in Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Diane eWhitmer

    2012-06-01

    Full Text Available Parkinson’s disease (PD is marked by excessive synchronous activity in the beta (8-35 Hz band throughout the cortico-basal ganglia network. The optimal location of high frequency deep brain stimulation (HF DBS within the subthalamic nucleus (STN region and the location of maximal beta hypersynchrony are currently matters of debate. Additionally, the effect of STN HF DBS on neural synchrony in functionally connected regions of motor cortex is unknown and of great interest. Scalp EEG studies demonstrated that stimulation of the STN can activate motor cortex antidromically, but the spatial specificity of this effect has not been examined. The present study examined the effect of STN HF DBS on neural synchrony within the cortico-basal ganglia network in patients with PD. We measured local field potentials dorsal to and within the STN of PD patients, and additionally in the motor cortex in a subset of these patients. We used diffusion tensor imaging (DTI to guide the placement of subdural cortical surface electrodes over the DTI-identified origin of the hyperdirect pathway between motor cortex and the STN. The results demonstrated that local beta power was attenuated during HF DBS both dorsal to and within the STN. The degree of attenuation was monotonic with increased DBS voltages in both locations, but this voltage-dependent effect was greater in the central STN than dorsal to the STN (p < 0.05. Cortical signals over the estimated origin of the hyperdirect pathway also demonstrated attenuation of beta hypersynchrony during DBS dorsal to or within STN, whereas signals from non-specific regions of motor cortex were not attenuated. The spatially specific suppression of beta synchrony in the motor cortex support the hypothesis that DBS may treat Parkinsonism by reducing excessive synchrony in the functionally connected sensorimotor network.

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

    Directory of Open Access Journals (Sweden)

    Nathaniel R. Bridges

    2018-03-01

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

  4. The effect of electric field maximum on the Rabi flopping and generated higher frequency spectra

    International Nuclear Information System (INIS)

    Niu Yueping; Cui Ni; Xiang Yang; Li Ruxin; Gong Shangqing; Xu Zhizhan

    2008-01-01

    We investigate the effect of the electric field maximum on the Rabi flopping and the generated higher frequency spectra properties by solving Maxwell-Bloch equations without invoking any standard approximations. It is found that the maximum of the electric field will lead to carrier-wave Rabi flopping (CWRF) through reversion dynamics which will be more evident when the applied field enters the sub-one-cycle regime. Therefore, under the interaction of sub-one-cycle pulses, the Rabi flopping follows the transient electric field tightly through the oscillation and reversion dynamics, which is in contrast to the conventional envelope Rabi flopping. Complete or incomplete population inversion can be realized through the control of the carrier-envelope phase (CEP). Furthermore, the generated higher frequency spectra will be changed from distinct to continuous or irregular with the variation of the CEP. Our results demonstrate that due to the evident maximum behavior of the electric field, pulses with different CEP give rise to different CWRFs, and then different degree of interferences lead to different higher frequency spectral features.

  5. Effects of cervical low-frequency electrical stimulation with various waveforms and densities on body mass, liver and kidney function, and death rate in ischemic stroke rats

    Institute of Scientific and Technical Information of China (English)

    Yonghong Yang; Chengqi He; Lin Yang; Qiang Gao; Shasha Li; Jing He

    2011-01-01

    Low-frequency electrical stimulation has resulted in favorable effects in the treatment of post-stroke dysphagia. However, the safety of cervical low-frequency electrical stimulation remains unclear because of numerous nerves and blood vessels in the neck. In the present study, rats with ischemic stroke underwent low-frequency electrical stimulation, and systemic and local effects of electrical stimulation at different densities and waveforms were investigated. Electrical stimulation resulted in no significant effects on body mass, liver or kidney function, or mortality rate. In addition, no significant adverse reaction was observed, despite overly high intensity of low-frequency electrical stimulation, which induced laryngismus, results from the present study suggested that it is safe to stimulate the neck with a low-frequency electricity under certain intensities.

  6. Metabolic costs of force generation for constant-frequency and catchlike-inducing electrical stimulation in human tibialis anterior muscle

    DEFF Research Database (Denmark)

    Ratkevicius, Aivaras; Quistorff, Bjørn

    2002-01-01

    -frequency trains, catchlike-inducing trains produced a faster force generation and were more effective in maintaining the force--time integral as well as peak force. However, ATP costs of force generation were similar for the catchlike-inducing and constant-frequency stimulation (6.7 plus/minus 1.1 and 6.6 plus......Metabolic costs of force generation were compared for constant-frequency and catchlike-inducing electrical stimulation. Repetitive catchlike-inducing trains consisted of 2 interpulse intervals (IPIs) at 12.5 ms, 1 IPI at 25 ms, and 5 IPIs at 50 ms. Constant-frequency trains consisted of 8 IPIs...... at 37.5 ms. One train was delivered to the peroneal nerve every 2.5 s for 36 times under ischemic conditions. Anaerobic adenosine triphosphate (ATP) turnover was determined using 31-phosphorus magnetic resonance spectroscopy (P-MRS) of the human tibialis anterior muscle. Compared with constant...

  7. Kilohertz and Low-Frequency Electrical Stimulation With the Same Pulse Duration Have Similar Efficiency for Inducing Isometric Knee Extension Torque and Discomfort.

    Science.gov (United States)

    Medeiros, Flávia Vanessa; Bottaro, Martim; Vieira, Amilton; Lucas, Tiago Pires; Modesto, Karenina Arrais; Bo, Antonio Padilha L; Cipriano, Gerson; Babault, Nicolas; Durigan, João Luiz Quagliotti

    2017-06-01

    To test the hypotheses that, as compared with pulsed current with the same pulse duration, kilohertz frequency alternating current would not differ in terms of evoked-torque production and perceived discomfort, and as a result, it would show the same current efficiency. A repeated-measures design with 4 stimuli presented in random order was used to test 25 women: (1) 500-microsecond pulse duration, (2) 250-microsecond pulse duration, (3) 500-microsecond pulse duration and low carrier frequency (1 kHz), (4) 250-microsecond pulse duration and high carrier frequency (4 kHz). Isometric peak torque of quadriceps muscle was measured using an isokinetic dynamometer. Discomfort was measured using a visual analog scale. Currents with long pulse durations induced approximately 21% higher evoked torque than short pulse durations. In addition, currents with 500 microseconds delivered greater amounts of charge than stimulation patterns using 250-microsecond pulse durations (P torque and discomfort. However, neuromuscular electrical stimulation (NMES) with longer pulse duration induces higher NMES-evoked torque, regardless of the carrier frequency. Pulse duration is an important variable that should receive more attention for an optimal application of NMES in clinical settings.

  8. Simultaneous masking between electric and acoustic stimulation in cochlear implant users with residual low-frequency hearing.

    Science.gov (United States)

    Krüger, Benjamin; Büchner, Andreas; Nogueira, Waldo

    2017-09-01

    Ipsilateral electric-acoustic stimulation (EAS) is becoming increasingly important in cochlear implant (CI) treatment. Improvements in electrode designs and surgical techniques have contributed to improved hearing preservation during implantation. Consequently, CI implantation criteria have been expanded toward people with significant residual low-frequency hearing, who may benefit from the combined use of both the electric and acoustic stimulation in the same ear. However, only few studies have investigated the mutual interaction between electric and acoustic stimulation modalities. This work characterizes the interaction between both stimulation modalities using psychophysical masking experiments and cone beam computer tomography (CBCT). Two psychophysical experiments for electric and acoustic masking were performed to measure the hearing threshold elevation of a probe stimulus in the presence of a masker stimulus. For electric masking, the probe stimulus was an acoustic tone while the masker stimulus was an electric pulse train. For acoustic masking, the probe stimulus was an electric pulse train and the masker stimulus was an acoustic tone. Five EAS users, implanted with a CI and ipsilateral residual low-frequency hearing, participated in the study. Masking was determined at different electrodes and different acoustic frequencies. CBCT scans were used to determine the individual place-pitch frequencies of the intracochlear electrode contacts by using the Stakhovskaya place-to-frequency transformation. This allows the characterization of masking as a function of the difference between electric and acoustic stimulation sites, which we term the electric-acoustic frequency difference (EAFD). The results demonstrate a significant elevation of detection thresholds for both experiments. In electric masking, acoustic-tone thresholds increased exponentially with decreasing EAFD. In contrast, for the acoustic masking experiment, threshold elevations were present

  9. Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation.

    Directory of Open Access Journals (Sweden)

    Katsuya Kobayashi

    Full Text Available Physiological high frequency activities (HFA are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections, or different terminal layers (layer IV vs. layer II/III affect its frequency, we, in the primary somatosensory cortex (SI, compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response and N80 (late response of somatosensory evoked potentials (HFA(SEP(N20 and HFA(SEP(N80 and compared those overriding N1 and N2 (first and second responses of cortico-cortical evoked potentials (HFA(CCEP(N1 and HFA(CCEP(N2. HFA(SEP(N20 showed the power peak in the frequency above 200 Hz, while HFA(CCEP(N1 had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFA(CCEP(N1 and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions.

  10. Object Categorization in Finer Levels Relies More on Higher Spatial Frequencies and Takes Longer.

    Science.gov (United States)

    Ashtiani, Matin N; Kheradpisheh, Saeed R; Masquelier, Timothée; Ganjtabesh, Mohammad

    2017-01-01

    advantage of the superordinate (resp. basic) level to basic (resp. subordinate) level is mainly due to the computational constraints (the visual system processes higher spatial frequencies more slowly, and categorization in finer levels depends more on these higher spatial frequencies).

  11. Hippocampal low-frequency stimulation inhibits afterdischarge and increases GABA (A) receptor expression in amygdala-kindled pharmacoresistant epileptic rats.

    Science.gov (United States)

    Wu, Guofeng; Wang, Likun; Hong, Zhen; Ren, Siying; Zhou, Feng

    2017-08-01

    The purpose of the present study was to observe the effects of hippocampal low-frequency stimulation (Hip-LFS) on amygdala afterdischarge and GABA (A) receptor expression in pharmacoresistant epileptic (PRE) rats. A total of 110 healthy adult male Wistar rats were used to generate a model of epilepsy by chronic stimulation of the amygdala. Sixteen PRE rats were selected from 70 amygdala-kindled rats by testing their response to Phenytoin and Phenobarbital, and they were randomly assigned to a pharmacoresistant stimulation group (PRS group, 8 rats) or a pharmacoresistant control group (PRC group, 8 rats). A stimulation electrode was implanted into the hippocampus of all of the rats. Hip-LFS was administered twice per day in the PRS group for two weeks. Simultaneously, amygdala stimulus-induced seizures and afterdischarge were recorded. After the hippocampal stimulation was terminated, the brain tissues were obtained to determine the GABA (A) receptors by a method of immumohistochemistry and a real-time polymerase chain reaction. The stages and duration of the amygdala stimulus-induced epileptic seizures were decreased in the PRS group. The afterdischarge threshold was increased and the duration as well as the afterdischarge frequency was decreased. Simultaneously, the GABA (A) expression was significantly increased in the PRS group. Hip-LFS may inhibit amygdala stimulus-induced epileptic seizures and up-regulate GABA (A) receptor expression in PRE rats. The antiepileptic effects of hippocampal stimulation may be partly achieved by increasing the GABA (A) receptor.

  12. Antihypertensive effect of low-frequency transcutaneous electrical nerve stimulation (TENS) in comparison with drug treatment.

    Science.gov (United States)

    Silverdal, Jonas; Mourtzinis, Georgios; Stener-Victorin, Elisabet; Mannheimer, Clas; Manhem, Karin

    2012-10-01

    Hypertension is a major risk factor for vascular disease, yet blood pressure (BP) control is unsatisfactory low, partly due to side-effects. Transcutaneous electrical nerve stimulation (TENS) is well tolerated and studies have demonstrated BP reduction. In this study, we compared the BP lowering effect of 2.5 mg felodipin once daily with 30 min of bidaily low-frequency TENS in 32 adult hypertensive subjects (mean office BP 152.7/90.0 mmHg) in a randomized, crossover design. Office BP and 24-h ambulatory BP monitoring (ABPM) were performed at baseline and at the end of each 4-week treatment and washout period. Felodipin reduced office BP by 10/6 mmHg (p TENS reduced office BP by 5/1.5 mmHg (p TENS washout, BP was further reduced and significantly lower than at baseline, but at levels similar to BP after felodipin washout and therefore reasonably caused by factors other than the treatment per se. ABPM revealed a significant systolic reduction of 3 mmHg by felodipin, but no significant changes were noted after TENS. We conclude that our study does not present any solid evidence of BP reduction of TENS.

  13. Factor Analysis of Low-Frequency Repetitive Transcranial Magnetic Stimulation to the Temporoparietal Junction for Tinnitus

    Directory of Open Access Journals (Sweden)

    Hui Wang

    2016-01-01

    Full Text Available Objectives. We investigated factors that contribute to suppression of tinnitus after repetitive transcranial magnetic stimulation (rTMS. Methods. A total of 289 patients with tinnitus underwent active 1 Hz rTMS in the left temporoparietal region. A visual analog scale (VAS was used to assess tinnitus loudness. All participants were interviewed regarding age, gender, tinnitus duration, laterality and pitch, audiometric parameters, sleep, and so forth. The resting motor thresholds (RMTs were measured in all patients and 30 age- and gender-matched volunteers. Results. With respect to different factors that contribute to tinnitus suppression, we found improvement in the following domains: shorter duration, normal hearing (OR: 3.25, 95%CI: 2.01–5.27, p=0.001, and without sleep disturbance (OR: 2.51, 95%CI: 1.56–4.1, p=0.005 adjusted for age and gender. The patients with tinnitus lasting less than 1 year were more likely to show suppression of tinnitus (OR: 2.77, 95%CI: 1.48–5.19, p=0.002 compared to those with tinnitus lasting more than 5 years. Tinnitus patients had significantly lower RMTs compared with healthy volunteers. Conclusion. Active low-frequency rTMS results in a significant reduction in the loudness of tinnitus. Significant tinnitus suppression was shown in subjects with shorter tinnitus duration, with normal hearing, and without sleep disturbance.

  14. Factor Analysis of Low-Frequency Repetitive Transcranial Magnetic Stimulation to the Temporoparietal Junction for Tinnitus

    Science.gov (United States)

    Li, Bei; Wang, Meiye; Li, Ming; Yin, Shankai

    2016-01-01

    Objectives. We investigated factors that contribute to suppression of tinnitus after repetitive transcranial magnetic stimulation (rTMS). Methods. A total of 289 patients with tinnitus underwent active 1 Hz rTMS in the left temporoparietal region. A visual analog scale (VAS) was used to assess tinnitus loudness. All participants were interviewed regarding age, gender, tinnitus duration, laterality and pitch, audiometric parameters, sleep, and so forth. The resting motor thresholds (RMTs) were measured in all patients and 30 age- and gender-matched volunteers. Results. With respect to different factors that contribute to tinnitus suppression, we found improvement in the following domains: shorter duration, normal hearing (OR: 3.25, 95%CI: 2.01–5.27, p = 0.001), and without sleep disturbance (OR: 2.51, 95%CI: 1.56–4.1, p = 0.005) adjusted for age and gender. The patients with tinnitus lasting less than 1 year were more likely to show suppression of tinnitus (OR: 2.77, 95%CI: 1.48–5.19, p = 0.002) compared to those with tinnitus lasting more than 5 years. Tinnitus patients had significantly lower RMTs compared with healthy volunteers. Conclusion. Active low-frequency rTMS results in a significant reduction in the loudness of tinnitus. Significant tinnitus suppression was shown in subjects with shorter tinnitus duration, with normal hearing, and without sleep disturbance. PMID:27847647

  15. HIGHER MODE FREQUENCY EFFECTS ON RESONANCE IN MACHINERY, STRUCTURES, AND PIPE SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, R.

    2010-05-02

    The complexities of resonance in multi-degree of freedom systems (multi-DOF) may be clarified using graphic presentations. Multi-DOF systems represent actual systems, such as beams or springs, where multiple, higher order, natural frequencies occur. Resonance occurs when a cyclic load is applied to a structure, and the frequency of the applied load equals one of the natural frequencies. Both equations and graphic presentations are available in the literature for single degree of freedom (SDOF) systems, which describe the response of spring-mass-damper systems to harmonically applied, or cyclic, loads. Loads may be forces, moments, or forced displacements applied to one end of a structure. Multi-DOF systems are typically described only by equations in the literature, and while equations certainly permit a case by case analysis for specific conditions, graphs provide an overall comprehension not gleaned from single equations. In fact, this collection of graphed equations provides novel results, which describe the interactions between multiple natural frequencies, as well as a comprehensive description of increased vibrations near resonance.

  16. High and low frequency stimulation of the subthalamic nucleus induce prolonged changes in subthalamic and globus pallidus neurons

    Directory of Open Access Journals (Sweden)

    Hagar eLavian

    2013-12-01

    Full Text Available High frequency stimulation (HFS of the subthalamic nucleus (STN is widely used to treat the symptoms of Parkinson’s disease but the mechanism of this therapy is unclear. Using a rat brain slice preparation maintaining the connectivity between the STN and one of its target nuclei, the globus pallidus (GP, we investigated the effects of high and low frequency stimulation (HFS 100 Hz, LFS 10 Hz on activity of single neurons in the STN and GP. Both HFS and LFS caused changes in firing frequency and pattern of subthalamic and pallidal neurons. These changes were of synaptic origin, as they were abolished by glutamate and GABA antagonists. Both HFS and LFS also induced a long-lasting reduction in firing frequency in STN neurons possibly contending a direct causal link between HFS and the outcome DBS. In the GP both HFS and LFS induced either a long-lasting depression, or less frequently, a long-lasting excitation. Thus, in addition to the intrinsic activation of the stimulated neurons, long-lasting stimulation of the STN may trigger prolonged biochemical processes.

  17. Analysis of Higher Order Modes in Large Superconducting Radio Frequency Accelerating Structures

    CERN Document Server

    Galek, Tomasz; Brackebusch, Korinna; Van Rienen, Ursula

    2015-01-01

    Superconducting radio frequency cavities used for accelerating charged particle beams are commonly used in accelerator facilities around the world. The design and optimization of modern superconducting RF cavities requires intensive numerical simulations. Vast number of operational parameters must be calculated to ensure appropriate functioning of the accelerating structures. In this study, we primarily focus on estimation and behavior of higher order modes in superconducting RF cavities connected in chains. To calculate large RF models the state-space concatenation scheme, an efficient hybrid method, is employed.

  18. Changes in the frequency of swallowing during electrical stimulation of superior laryngeal nerve in rats.

    Science.gov (United States)

    Tsuji, Kojun; Tsujimura, Takanori; Magara, Jin; Sakai, Shogo; Nakamura, Yuki; Inoue, Makoto

    2015-02-01

    The aim of the present study was to investigate the adaptation of the swallowing reflex in terms of reduced swallowing reflex initiation following continuous superior laryngeal nerve stimulation. Forty-four male Sprague Dawley rats were anesthetized with urethane. To identify swallowing, electromyographic activity of the left mylohyoid and thyrohyoid muscles was recorded. To evoke the swallowing response, the superior laryngeal nerve (SLN), recurrent laryngeal nerve, or cortical swallowing area was electrically stimulated. Repetitive swallowing evoked by continuous SLN stimulation was gradually reduced, and this reduction was dependent on the resting time duration between stimulations. Prior SLN stimulation also suppressed subsequent swallowing initiation. The reduction in evoked swallows induced by recurrent laryngeal nerve or cortical swallowing area stimulation was less than that following superior laryngeal nerve stimulation. Decerebration had no effect on the reduction in evoked swallows. Prior subthreshold stimulation reduced subsequent initiation of swallowing, suggesting that there was no relationship between swallowing movement evoked by prior stimulation and the subsequent reduction in swallowing initiation. Overall, these data suggest that reduced sensory afferent nerve firing and/or trans-synaptic responses, as well as part of the brainstem central pattern generator, are involved in adaptation of the swallowing reflex following continuous stimulation of swallow-inducing peripheral nerves and cortical areas. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. High-frequency epidural stimulation across the respiratory cycle evokes phrenic short-term potentiation after incomplete cervical spinal cord injury.

    Science.gov (United States)

    Gonzalez-Rothi, Elisa J; Streeter, Kristi A; Hanna, Marie H; Stamas, Anna C; Reier, Paul J; Baekey, David M; Fuller, David D

    2017-10-01

    C2 spinal hemilesion (C2Hx) paralyzes the ipsilateral diaphragm, but recovery is possible through activation of "crossed spinal" synaptic inputs to ipsilateral phrenic motoneurons. We tested the hypothesis that high-frequency epidural stimulation (HF-ES) would potentiate ipsilateral phrenic output after subacute and chronic C2Hx. HF-ES (300 Hz) was applied to the ventrolateral C4 or T2 spinal cord ipsilateral to C2Hx in anesthetized and mechanically ventilated adult rats. Stimulus duration was 60 s, and currents ranged from 100 to 1,000 µA. Bilateral phrenic nerve activity and ipsilateral hypoglossal (XII) nerve activity were recorded before and after HF-ES. Higher T2 stimulus currents potentiated ipsilateral phasic inspiratory activity at both 2 and 12 wk post-C2Hx, whereas higher stimulus currents delivered at C4 potentiated ipsilateral phasic phrenic activity only at 12 wk ( P = 0.028). Meanwhile, tonic output in the ipsilateral phrenic nerve reached 500% of baseline values at the high currents with no difference between 2 and 12 wk. HF-ES did not trigger inspiratory burst-frequency changes. Similar responses occurred following T2 HF-ES. Increases in contralateral phrenic and XII nerve output were induced by C4 and T2 HF-ES at higher currents, but the relative magnitude of these changes was small compared with the ipsilateral phrenic response. We conclude that following incomplete cervical spinal cord injury, HF-ES of the ventrolateral midcervical or thoracic spinal cord can potentiate efferent phrenic motor output with little impact on inspiratory burst frequency. However, the substantial increases in tonic output indicate that the uninterrupted 60-s stimulation paradigm used is unlikely to be useful for respiratory muscle activation after spinal injury. NEW & NOTEWORTHY Previous studies reported that high-frequency epidural stimulation (HF-ES) activates the diaphragm following acute spinal transection. This study examined HF-ES and phrenic motor output

  20. Higher moments method for generalized Pareto distribution in flood frequency analysis

    Science.gov (United States)

    Zhou, C. R.; Chen, Y. F.; Huang, Q.; Gu, S. H.

    2017-08-01

    The generalized Pareto distribution (GPD) has proven to be the ideal distribution in fitting with the peak over threshold series in flood frequency analysis. Several moments-based estimators are applied to estimating the parameters of GPD. Higher linear moments (LH moments) and higher probability weighted moments (HPWM) are the linear combinations of Probability Weighted Moments (PWM). In this study, the relationship between them will be explored. A series of statistical experiments and a case study are used to compare their performances. The results show that if the same PWM are used in LH moments and HPWM methods, the parameter estimated by these two methods is unbiased. Particularly, when the same PWM are used, the PWM method (or the HPWM method when the order equals 0) shows identical results in parameter estimation with the linear Moments (L-Moments) method. Additionally, this phenomenon is significant when r ≥ 1 that the same order PWM are used in HPWM and LH moments method.

  1. Both the cutaneous sensation and phosphene perception are modulated in a frequency-specific manner during transcranial alternating current stimulation.

    Science.gov (United States)

    Turi, Zs; Ambrus, G G; Janacsek, K; Emmert, K; Hahn, L; Paulus, W; Antal, A

    2013-01-01

    Transcranial alternating current stimulation (tACS) is a non-invasive stimulation technique for shaping neuroplastic processes and possibly entraining ongoing neural oscillations in humans. Despite the growing number of studies using tACS, we know little about the procedural sensations caused by stimulation. In order to fill this gap, we explored the cutaneous sensation and phosphene perception during tACS. Twenty healthy participants took part in a randomized, single-blinded, sham-controlled study, where volunteers received short duration stimulation at 1.0 mA intensity between 2 to 250 Hz using the standard left motor cortex-contralateral supraorbital montage. We recorded the perception onset latency and the strength of the sensations assessed by visual rating scale as dependent variables. We found that tACS evoked both cutaneous sensation and phosphene perception in a frequency-dependent manner. Our results show that the most perceptible procedural sensations were induced in the beta and gamma frequency range, especially at 20 Hz, whereas minimal procedural sensations were indicated in the ripple range (140 and 250 Hz). We believe that our results provide a relevant insight into the procedural sensations caused by oscillatory currents, and will offer a basis for developing more sophisticated stimulation protocols and study designs for future investigations.

  2. High frequency electrical stimulation concurrently induces central sensitization and ipsilateral inhibitory pain modulation.

    Science.gov (United States)

    Vo, L; Drummond, P D

    2013-03-01

    In healthy humans, analgesia to blunt pressure develops in the ipsilateral forehead during various forms of limb pain. The aim of the current study was to determine whether this analgesic response is induced by ultraviolet B radiation (UVB), which evokes signs of peripheral sensitization, or by high-frequency electrical stimulation (HFS), which triggers signs of central sensitization. Before and after HFS and UVB conditioning, sensitivity to heat and to blunt and sharp stimuli was assessed at and adjacent to the treated site in the forearm. In addition, sensitivity to blunt pressure was measured bilaterally in the forehead. The effect of ipsilateral versus contralateral temple cooling on electrically evoked pain in the forearm was then examined, to determine whether HFS or UVB conditioning altered inhibitory pain modulation. UVB conditioning triggered signs of peripheral sensitization, whereas HFS conditioning triggered signs of central sensitization. Importantly, ipsilateral forehead analgesia developed after HFS but not UVB conditioning. In addition, decreases in electrically evoked pain at the HFS-treated site were greater during ipsilateral than contralateral temple cooling, whereas decreases at the UVB-treated site were similar during both procedures. HFS conditioning induced signs of central sensitization in the forearm and analgesia both in the ipsilateral forehead and the HFS-treated site. This ipsilateral analgesia was not due to peripheral sensitization or other non-specific effects, as it failed to develop after UVB conditioning. Thus, the supra-spinal mechanisms that evoke central sensitization might also trigger a hemilateral inhibitory pain modulation process. This inhibitory process could sharpen the boundaries of central sensitization or limit its spread. © 2012 European Federation of International Association for the Study of Pain Chapters.

  3. Subthalamic nucleus high-frequency stimulation modulates neuronal reactivity to cocaine within the reward circuit.

    Science.gov (United States)

    Hachem-Delaunay, Sabira; Fournier, Marie-Line; Cohen, Candie; Bonneau, Nicolas; Cador, Martine; Baunez, Christelle; Le Moine, Catherine

    2015-08-01

    The subthalamic nucleus (STN) is a critical component of a complex network controlling motor, associative and limbic functions. High-frequency stimulation (HFS) of the STN is an effective therapy for motor symptoms in Parkinsonian patients and can also reduce their treatment-induced addictive behaviors. Preclinical studies have shown that STN HFS decreases motivation for cocaine while increasing that for food, highlighting its influence on rewarding and motivational circuits. However, the cellular substrates of these effects remain unknown. Our objectives were to characterize the cellular consequences of STN HFS with a special focus on limbic structures and to elucidate how STN HFS may interfere with acute cocaine effects in these brain areas. Male Long-Evans rats were subjected to STN HFS (130 Hz, 60 μs, 50-150 μA) for 30 min before an acute cocaine injection (15 mg/kg) and sacrificed 10 min following the injection. Neuronal reactivity was analyzed through the expression of two immediate early genes (Arc and c-Fos) to decipher cellular responses to STN HFS and cocaine. STN HFS only activated c-Fos in the globus pallidus and the basolateral amygdala, highlighting a possible role on emotional processes via the amygdala, with a limited effect by itself in other structures. Interestingly, and despite some differential effects on Arc and c-Fos expression, STN HFS diminished the c-Fos response induced by acute cocaine in the striatum. By preventing the cellular effect of cocaine in the striatum, STN HFS might thus decrease the reinforcing properties of the drug, which is in line with the inhibitory effect of STN HFS on the rewarding and reinforcing properties of cocaine. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Glycogen depletion and resynthesis during 14 days of chronic low-frequency stimulation of rabbit muscle

    DEFF Research Database (Denmark)

    Prats, C; Bernal, C; Cadefau, J A

    2002-01-01

    Electro-stimulation alters muscle metabolism and the extent of this change depends on application intensity and duration. The effect of 14 days of chronic electro-stimulation on glycogen turnover and on the regulation of glycogen synthase in fast-twitch muscle was studied. The results showed that...

  5. The effects of high frequency subthalamic stimulation on balance performance and fear of falling in patients with Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Jarnlo Gun-Britt

    2009-04-01

    Full Text Available Abstract Background Balance impairment is one of the most distressing symptoms in Parkinson's disease (PD even with pharmacological treatment (levodopa. A complementary treatment is high frequency stimulation in the subthalamic nucleus (STN. Whether STN stimulation improves postural control is under debate. The aim of this study was to explore the effects of STN stimulation alone on balance performance as assessed with clinical performance tests, subjective ratings of fear of falling and posturography. Methods Ten patients (median age 66, range 59–69 years with bilateral STN stimulation for a minimum of one year, had their anti-PD medications withdrawn overnight. Assessments were done both with the STN stimulation turned OFF and ON (start randomized. In both test conditions, the following were assessed: motor symptoms (descriptive purposes, clinical performance tests, fear of falling ratings, and posturography with and without vibratory proprioceptive disturbance. Results STN stimulation alone significantly (p = 0.002 increased the scores of the Berg balance scale, and the median increase was 6 points. The results of all timed performance tests, except for sharpened Romberg, were significantly (p ≤ 0.016 improved. The patients rated their fear of falling as less severe, and the total score of the Falls-Efficacy Scale(S increased (p = 0.002 in median with 54 points. All patients completed posturography when the STN stimulation was turned ON, but three patients were unable to do so when it was turned OFF. The seven patients with complete data showed no statistical significant difference (p values ≥ 0.109 in torque variance values when comparing the two test situations. This applied both during quiet stance and during the periods with vibratory stimulation, and it was irrespective of visual input and sway direction. Conclusion In this sample, STN stimulation alone significantly improved the results of the clinical performance tests that mimic

  6. [Health-related quality of life assessment in depression after low-frequency transcranial magnetic stimulation].

    Science.gov (United States)

    Dumas, R; Boyer, L; Richieri, R; Guedj, E; Auquier, P; Lançon, C

    2014-02-01

    Major depressive disorder remains one of the leading causes of disability in developed countries despite pharmacological and psychological treatments. Patients with major depression have poorer health-related quality of life than persons of the general population, or patients with chronic somatic illness. Improvement of health-related quality of life in depression is thus a pertinent treatment objective. Both high-frequency repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex and low-frequency rTMS over the right dorsolateral prefrontal cortex have shown their effectiveness in medication-resistant depression. However, the Health-related Quality of Life questionnaire remains under-utilized to assess the effectiveness of rTMS in research or in a routine clinical setting. Our study aims to investigate in an open label trial the efficacy of low-frequency rTMS over the right dorsolateral prefrontal cortex on health-related quality of life and clinical outcomes in medication-resistant depression. In a naturalistic trial, 33 unipolar and bipolar patients with medication-resistant depression were treated with daily low-frequency rTMS over the right dorsolateral prefrontal cortex for 4 weeks. Health-related quality of life was assessed using the SF-36 questionnaire. The SF-36 is a generic, self-administered, and worldwide-used questionnaire, consisting of 36 items describing eight health dimensions: physical functioning, social functioning, role-physical problems, role-emotional problems, mental health, vitality, bodily pain, and general health. Physical component summary and mental component summary scores were then obtained. Depression severity was assessed using the 21-item self-report Beck Depression Inventory. Anxiety severity was assessed using the State-Trait Anxiety Inventory. The SF-36, the Beck Depression Inventory and the State-Trait Anxiety Inventory were assessed before and after low-frequency rTMS. The effect of r

  7. Preliminary Evidence of the Effects of High-frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Swallowing Functions in Post-Stroke Individuals with Chronic Dysphagia

    Science.gov (United States)

    Cheng, Ivy K. Y.; Chan, Karen M. K.; Wong, C. S.; Cheung, Raymond T. F.

    2015-01-01

    Background: There is growing evidence of potential benefits of repetitive transcranial magnetic stimulation (rTMS) in the rehabilitation of dysphagia. However, the site and frequency of stimulation for optimal effects are not clear. Aims: The aim of this pilot study is to investigate the short-term effects of high-frequency 5 Hz rTMS applied to…

  8. Dynamic stereotypic responses of basal ganglia neurons to subthalamic nucleus high frequency stimulation in the parkinsonian primate

    Directory of Open Access Journals (Sweden)

    Anan eMoran

    2011-04-01

    Full Text Available Deep brain stimulation in the subthalamic nucleus (STN is a well-established therapy for patients with severe Parkinson‟s disease (PD; however, its mechanism of action is still unclear. In this study we explored static and dynamic activation patterns in the basal ganglia during high frequency macro-stimulation of the STN. Extracellular multi-electrode recordings were performed in primates rendered parkinsonian using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Recordings were preformed simultaneously in the STN and the globus pallidus externus and internus. Single units were recorded preceding and during the stimulation. During the stimulation, STN mean firing rate dropped significantly, while pallidal mean firing rates did not change significantly. The vast majority of neurons across all three nuclei displayed stimulation driven modulations, which were stereotypic within each nucleus but differed across nuclei. The predominant response pattern of STN neurons was somatic inhibition. However, most pallidal neurons demonstrated synaptic activation patterns. A minority of neurons across all nuclei displayed axonal activation. Temporal dynamics were observed in the response to stimulation over the first 10 seconds in the STN and over the first 30 seconds in the pallidum. In both pallidal segments, the synaptic activation response patterns underwent delay and decay of the magnitude of the peak response due to short term synaptic depression. We suggest that during STN macro stimulation the STN goes through a functional ablation as its upper bound on information transmission drops significantly. This notion is further supported by the evident dissociation between the stimulation driven pre-synaptic STN somatic inhibition and the post-synaptic axonal activation of its downstream targets. Thus, basal ganglia output maintains its firing rate while losing the deleterious effect of the STN. This may be a part of the mechanism leading to the beneficial

  9. Dynamic stereotypic responses of Basal Ganglia neurons to subthalamic nucleus high-frequency stimulation in the parkinsonian primate.

    Science.gov (United States)

    Moran, Anan; Stein, Edward; Tischler, Hadass; Belelovsky, Katya; Bar-Gad, Izhar

    2011-01-01

    Deep brain stimulation (DBS) in the subthalamic nucleus (STN) is a well-established therapy for patients with severe Parkinson's disease (PD); however, its mechanism of action is still unclear. In this study we explored static and dynamic activation patterns in the basal ganglia (BG) during high-frequency macro-stimulation of the STN. Extracellular multi-electrode recordings were performed in primates rendered parkinsonian using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Recordings were preformed simultaneously in the STN and the globus pallidus externus and internus. Single units were recorded preceding and during the stimulation. During the stimulation, STN mean firing rate dropped significantly, while pallidal mean firing rates did not change significantly. The vast majority of neurons across all three nuclei displayed stimulation driven modulations, which were stereotypic within each nucleus but differed across nuclei. The predominant response pattern of STN neurons was somatic inhibition. However, most pallidal neurons demonstrated synaptic activation patterns. A minority of neurons across all nuclei displayed axonal activation. Temporal dynamics were observed in the response to stimulation over the first 10 seconds in the STN and over the first 30 seconds in the pallidum. In both pallidal segments, the synaptic activation response patterns underwent delay and decay of the magnitude of the peak response due to short term synaptic depression. We suggest that during STN macro-stimulation the STN goes through a functional ablation as its upper bound on information transmission drops significantly. This notion is further supported by the evident dissociation between the stimulation driven pre-synaptic STN somatic inhibition and the post-synaptic axonal activation of its downstream targets. Thus, BG output maintains its firing rate while losing the deleterious effect of the STN. This may be a part of the mechanism leading to the beneficial effect of DBS in PD.

  10. Electrical high frequency stimulation in the dorsal striatum: Effects on response learning and on GABA levels in rats.

    Science.gov (United States)

    Schumacher, Anett; de Vasconcelos, Anne Pereira; Lecourtier, Lucas; Moser, Andreas; Cassel, Jean-Christophe

    2011-09-23

    Electrical high frequency stimulation (HFS) has been used to treat various neurological and psychiatric diseases. The striatal area contributes to response learning and procedural memory. Therefore, we investigated the effect of striatal HFS application on procedural/declarative-like memory in rats. All rats were trained in a flooded Double-H maze for three days (4 trials/day) to swim to an escape platform hidden at a constant location. The starting place was the same for all trials. After each training session, HFS of the left dorsal striatum was performed over 4h in alternating 20 min periods (during rest time, 10a.m. to 3p.m.). Nineteen hours after the last HFS and right after a probe trial assessing the rats' strategy (procedural vs. declarative-like memory-based choice), animals were sacrificed and the dorsal striatum was quickly removed. Neurotransmitter levels were measured by HPLC. Stimulated rats did not differ from sham-operated and control rats in acquisition performance, but exhibited altered behavior during the probe trial (procedural memory responses being less frequent than in controls). In stimulated rats, GABA levels were significantly increased in the dorsal striatum on both sides. We suggest that HFS of the dorsal striatum does not alter learning behavior in rats but influences the strategy by which the rats solve the task. Given that the HFS-induced increase of GABA levels was found 19 h after stimulation, it can be assumed that HFS has consequences lasting for several hours and which are functionally significant at a behavioral level, at least under our stimulation (frequency, timing, location, side and strength of stimulation) and testing conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. High- and low-frequency transcutaneous electrical nerve stimulation does not reduce experimental pain in elderly individuals

    OpenAIRE

    Bergeron-V?zina, Kayla; Corriveau, H?l?ne; Martel, Marylie; Harvey, Marie-Philippe; L?onard, Guillaume

    2015-01-01

    Abstract Despite its widespread clinical use, the efficacy of transcutaneous electrical nerve stimulation (TENS) remains poorly documented in elderly individuals. In this randomized, double-blind crossover study, we compared the efficacy of high-frequency (HF), low-frequency (LF), and placebo (P) TENS in a group of 15 elderly adults (mean age: 67 ? 5 years). The effect of HF-, LF-, and P-TENS was also evaluated in a group of 15 young individuals (26 ? 5 years; same study design) to validate t...

  12. Effect of Low Frequency Neuromuscular Electrical Stimulation on Glucose Profile of Persons with Type 2 Diabetes: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Georges Jabbour

    2015-06-01

    Full Text Available The purpose of this study was to examine the effect of low-frequency neuromuscular electrical stimulation (NMES on glucose profile in persons with type 2 diabetes mellitus (T2DM. Eight persons with T2DM (41 to 65 years completed a glucose tolerance test with and without NMES delivered to the knee extensors for a 1-hour period at 8 Hz. Three blood samples were collected: at rest, and then 60 and 120 minutes after consumption of a glucose load on the NMES and control days. In NMES groups glucose concentrations were significantly lower (P<0.01 than in the control conditions. Moreover, a significant positive correlation (r=0.9, P<0.01 was obtained between the intensity of stimulation and changes in blood glucose. Our results suggest that low-frequency stimulation seem suitable to induce enhance glucose uptake in persons with T2DM. Moreover, the intensity of stimulation reflecting the motor contraction should be considered during NMES procedure.

  13. High-Frequency Stimulation of Dorsal Column Axons: Potential Underlying Mechanism of Paresthesia-Free Neuropathic Pain Relief.

    Science.gov (United States)

    Arle, Jeffrey E; Mei, Longzhi; Carlson, Kristen W; Shils, Jay L

    2016-06-01

    Spinal cord stimulation (SCS) treats neuropathic pain through retrograde stimulation of dorsal column axons and their inhibitory effects on wide dynamic range (WDR) neurons. Typical SCS uses frequencies from 50-100 Hz. Newer stimulation paradigms use high-frequency stimulation (HFS) up to 10 kHz and produce pain relief but without paresthesia. Our hypothesis is that HFS preferentially blocks larger diameter axons (12-15 µm) based on dynamics of ion channel gates and the electric potential gradient seen along the axon, resulting in inhibition of WDR cells without paresthesia. We input field potential values from a finite element model of SCS into an active axon model with ion channel subcomponents for fiber diameters 1-20 µm and simulated dynamics on a 0.001 msec time scale. Assuming some degree of wave rectification seen at the axon, action potential (AP) blockade occurs as hypothesized, preferentially in larger over smaller diameters with blockade in most medium and large diameters occurring between 4.5 and 10 kHz. Simulations show both ion channel gate and virtual anode dynamics are necessary. At clinical HFS frequencies and pulse widths, HFS preferentially blocks larger-diameter fibers and concomitantly recruits medium and smaller fibers. These effects are a result of interaction between ion gate dynamics and the "activating function" (AF) deriving from current distribution over the axon. The larger fibers that cause paresthesia in low-frequency simulation are blocked, while medium and smaller fibers are recruited, leading to paresthesia-free neuropathic pain relief by inhibiting WDR cells. © 2016 International Neuromodulation Society.

  14. Combined sub-threshold dosages of phenobarbital and low-frequency stimulation effectively reduce seizures in amygdala-kindled rats.

    Science.gov (United States)

    Asgari, Azam; Semnanian, Saeed; Atapour, Nafiseh; Shojaei, Amir; Moradi, Homeira; Mirnajafi-Zadeh, Javad

    2014-08-01

    Low-frequency stimulation (LFS) is a potential therapy utilized in patients who do not achieve satisfactory control of seizures with pharmacological treatments. Here, we investigated the interaction between anticonvulsant effects of LFS and phenobarbital (a commonly used medicine) on amygdala-kindled seizures in rats. Animals were kindled by electrical stimulation of basolateral amygdala in a rapid manner (12 stimulations/day). Fully kindled animals randomly received one of the three treatment choices: phenobarbital (1, 2, 3, 4 and 8 mg/kg; i.p.; 30 min before kindling stimulation), LFS (one or 4 packages contained 100 or 200 monophasic square wave pulses, 0.1-ms pulse duration at 1 Hz, immediately before kindling stimulation) or a combination of both (phenobarbital at 3 mg/kg and LFS). Phenobarbital alone at the doses of 1, 2 and 3 mg/kg had no significant effect on the main seizure parameters. LFS application always produced anticonvulsant effects unless applied with the pattern of one package of 100 pulses, which is considered as non-effective. All the seizure parameters were significantly reduced when phenobarbital (3 mg/kg) was administered prior to the application of the non-effective pattern of LFS. Phenobarbital (3 mg/kg) also increased the anticonvulsant actions of the effective LFS pattern. Our results provide an evidence of a positive cumulative anticonvulsant effect of LFS and phenobarbital, suggesting a potential combination therapy at sub-threshold dosages of phenobarbital and LFS to achieve a satisfactory clinical effect.

  15. High-Frequency Stimulation at the Subthalamic Nucleus Suppresses Excessive Self-Grooming in Autism-Like Mouse Models.

    Science.gov (United States)

    Chang, Andrew D; Berges, Victoria A; Chung, Sunho J; Fridman, Gene Y; Baraban, Jay M; Reti, Irving M

    2016-06-01

    Approximately one quarter of individuals with an autism spectrum disorder (ASD) display self-injurious behavior (SIB) ranging from head banging to self-directed biting and punching. Sometimes, these behaviors are extreme and unresponsive to pharmacological and behavioral therapies. We have found electroconvulsive therapy (ECT) can produce life-changing results, with more than 90% suppression of SIB frequency. However, these patients typically require frequent maintenance ECT (mECT), as often as every 5 days, to sustain the improvement gained during the acute course. Long-term consequences of such frequent mECT started as early as childhood in some cases are unknown. Accordingly, there is a need for alternative forms of chronic stimulation for these patients. To explore the feasibility of deep brain stimulation (DBS) for intractable SIB seen in some patients with an ASD, we utilized two genetically distinct mouse models demonstrating excessive self-grooming, namely the Viaat-Mecp2(-/y) and Shank3B(-/-) lines, and administered high-frequency stimulation (HFS) via implanted electrodes at the subthalamic nucleus (STN-HFS). We found that STN-HFS significantly suppressed excessive self-grooming in both genetic lines. Suppression occurs both acutely when stimulation is switched on, and persists for several days after HFS is stopped. This effect was not explained by a change in locomotor activity, which was unaffected by STN-HFS. Likewise, social interaction deficits were not corrected by STN-HFS. Our data show STN-HFS suppresses excessive self-grooming in two autism-like mouse models, raising the possibility DBS might be used to treat intractable SIB associated with ASDs. Further studies are required to explore the circuitry engaged by STN-HFS, as well as other potential stimulation sites. Such studies might also yield clues about pathways, which could be modulated by non-invasive stimulatory techniques.

  16. High-Frequency Repetitive Sensory Stimulation as Intervention to Improve Sensory Loss in Patients with Complex Regional Pain Syndrome I.

    Science.gov (United States)

    David, Marianne; Dinse, Hubert R; Mainka, Tina; Tegenthoff, Martin; Maier, Christoph

    2015-01-01

    Achieving perceptual gains in healthy individuals or facilitating rehabilitation in patients is generally considered to require intense training to engage neuronal plasticity mechanisms. Recent work, however, suggested that beneficial outcome similar to training can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation (rSS). For example, high-frequency repetitive sensory stimulation (HF-rSS) enhances tactile performance and induces cortical reorganization in healthy subjects and patients after stroke. Patients with complex regional pain syndrome (CRPS) show impaired tactile performance associated with shrinkage of cortical maps. We here investigated the feasibility and efficacy of HF-rSS, and low-frequency rSS (LF-rSS) to enhance tactile performance and reduce pain intensity in 20 patients with CRPS type I. Intermittent high- or low-frequency electrical stimuli were applied for 45 min/day to all fingertips of the affected hand for 5 days. Main outcome measures were spatial two-point-discrimination thresholds and mechanical detection thresholds measured on the tip of the index finger bilaterally. Secondary endpoint was current pain intensity. All measures were assessed before and on day 5 after the last stimulation session. HF-rSS applied in 16 patients improved tactile discrimination on the affected hand significantly without changes contralaterally. Current pain intensity remained unchanged on average, but decreased in four patients by ≥30%. This limited pain relief might be due to the short stimulation period of 5 days only. In contrast, after LF-rSS, tactile discrimination was impaired in all four patients, while detection thresholds and pain were not affected. Our data suggest that HF-rSS could be used as a novel approach in CRPS treatment to improve sensory loss. Longer treatment periods might be required to induce consistent pain relief.

  17. High frequency repetitive sensory stimulation as intervention to improve sensory loss in patients with complex regional pain syndrome (CRPS I

    Directory of Open Access Journals (Sweden)

    Marianne eDavid

    2015-11-01

    Full Text Available Achieving perceptual gains in healthy individuals, or facilitating rehabilitation in patients is generally considered to require intense training to engage neuronal plasticity mechanisms. Recent work, however, suggested that beneficial outcome similar to training can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation (rSS. For example, high-frequency repetitive sensory stimulation (HF-rSS enhances tactile performance and induces cortical reorganization in healthy subjects and patients after stroke. Patients with complex regional pain syndrome (CRPS show impaired tactile performance associated with shrinkage of cortical maps. We here investigated the feasibility and efficacy of HF-rSS, and low-frequency rSS (LF-rSS to enhance tactile performance and reduce pain intensity in 20 patients with CRPS type I. Intermittent high or low frequency electrical stimuli were applied for 45min/day to all fingertips of the affected hand for 5 days. Main outcome measures were spatial 2-point-discrimination thresholds and mechanical detection thresholds measured on the tip of the index finger bilaterally. Secondary endpoint was current pain intensity. All measures were assessed before and on day 5 after the last stimulation session. HF-rSS applied in 16 patients improved tactile discrimination on the affected hand significantly without changes contralaterally. Current pain intensity remained unchanged on average, but decreased in 4 patients by 30%. This limited pain relief might be due to the short stimulation period of 5 days only. In contrast, after LF-rSS, tactile discrimination was impaired in all 4 patients, while detection thresholds and pain were not affected. Our data suggest that HF-rSS could be used as a novel approach in CRPS treatment to improve sensory loss. Longer treatment periods might be required to induce consistent pain relief.

  18. Higher balance task demands are associated with an increase in individual alpha peak frequency

    Directory of Open Access Journals (Sweden)

    Thorben eHülsdünker

    2016-01-01

    Full Text Available Balance control is fundamental for most daily motor activities, and its impairment is associated with an increased risk of falling. Growing evidence suggests the human cortex is essentially contributing to the control of standing balance. However, the exact mechanisms remain unclear and need further investigation. In a previous study we introduced a new protocol to identify electrocortical activity associated with performance of different continuous balance tasks with the eyes opened. The aim of this study was to extend our previous results by investigating the individual alpha peak frequency (iAPF, a neurophysiological marker of thalamo-cortical information transmission, which remained unconsidered so far in balance research. Thirty-seven subjects completed nine balance tasks varying in surface stability and base of support. Electroencephalography (EEG was recorded from 32 scalp locations throughout balancing with the eyes closed to ensure reliable identification of the iAPF. Balance performance was quantified as the sum of anterior-posterior and medio-lateral movements of the supporting platform. The iAPF, as well as power in the theta, lower alpha and upper alpha frequency bands were determined for each balance task after applying an ICA-based artifact rejection procedure. Higher demands on balance control were associated with a global increase in iAPF and a decrease in lower alpha power. These results may indicate increased thalamo-cortical information transfer and general cortical activation, respectively. In addition, a significant increase in upper alpha activity was observed in the fronto-central region whereas it decreased in the centro-parietal region. Furthermore, midline theta increased with higher task demands probably indicating activation of error detection/processing mechanisms. IAPF as well as theta and alpha power were correlated with platform movements. The results provide new insights into spectral and spatial characteristics

  19. Measurement of optical-beat frequency in a photoconductive terahertz-wave generator using microwave higher harmonics.

    Science.gov (United States)

    Murasawa, Kengo; Sato, Koki; Hidaka, Takehiko

    2011-05-01

    A new method for measuring optical-beat frequencies in the terahertz (THz) region using microwave higher harmonics is presented. A microwave signal was applied to the antenna gap of a photoconductive (PC) device emitting a continuous electromagnetic wave at about 1 THz by the photomixing technique. The microwave higher harmonics with THz frequencies are generated in the PC device owing to the nonlinearity of the biased photoconductance, which is briefly described in this article. Thirteen nearly periodic peaks in the photocurrent were observed when the microwave was swept from 16 to 20 GHz at a power of -48 dBm. The nearly periodic peaks are generated by the homodyne detection of the optical beat with the microwave higher harmonics when the frequency of the harmonics coincides with the optical-beat frequency. Each peak frequency and its peak width were determined by fitting a Gaussian function, and the order of microwave harmonics was determined using a coarse (i.e., lower resolution) measurement of the optical-beat frequency. By applying the Kalman algorithm to the peak frequencies of the higher harmonics and their standard deviations, the optical-beat frequency near 1 THz was estimated to be 1029.81 GHz with the standard deviation of 0.82 GHz. The proposed method is applicable to a conventional THz-wave generator with a photomixer.

  20. High-frequency stimulation of the globus pallidus interna nucleus modulates GFRα1 gene expression in the basal ganglia.

    Science.gov (United States)

    Ho, Duncun Xun Kiat; Tan, Yong Chee; Tan, Jiayi; Too, Heng Phon; Ng, Wai Hoe

    2014-04-01

    Deep brain stimulation (DBS) is an established therapy for movement disorders such as Parkinson's disease (PD). Although the efficacy of DBS is clear, its precise molecular mechanism remains unknown. The glial cell line derived factor (GDNF) family of ligands has been shown to confer neuroprotective effects on dopaminergic neurons, and putaminal infusion of GDNF have been investigated in PD patients with promising results. Despite the potential therapeutic role of GDNF in alleviating motor symptoms, there is no data on the effects of electrical stimulation on GDNF-family receptor (GFR) expression in the basal ganglia structures. Here, we report the effects of electrical stimulation on GFRα1 isoforms, particularly GFRα1a and GFRα1b. Wistar rats underwent 2 hours of high frequency stimulation (HFS) at the globus pallidus interna nucleus. A control group was subjected to a similar procedure but without stimulation. The HFS group, sacrificed 24 hours after treatment, had a threefold decrease in mRNA expression level of GFRα1b (p=0.037), but the expression level reverted to normal 72 hours after stimulation. Our preliminary data reveal the acute effects of HFS on splice isoforms of GFRα1, and suggest that HFS may modulate the splice isoforms of GFRα1a and GFRα1b to varying degrees. Going forward, elucidating the interactions between HFS and GFR may shed new insights into the complexity of GDNF signaling in the nervous system and lead to better design of clinical trials using these signaling pathways to halt disease progression in PD and other neurodegenerative diseases. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Can Higher Education Stimulate Entrepreneurial Intentions among Engineering and Business Students?

    Science.gov (United States)

    Herman, Emilia; Stefanescu, Daniela

    2017-01-01

    This paper approaches the issue of higher entrepreneurship education in motivating young people to start their own business as a viable alternative to the successful integration of university graduates on the labour market. The fundamental question of this research is if, currently, entrepreneurship education influences students' entrepreneurial…

  2. Radioactive stimulated mutagenesis for a higher crop yield - past and present examples from Slovakia

    International Nuclear Information System (INIS)

    Micieta, K.; Murin, G.

    2015-01-01

    Radiation resistance of Vicia faba L. seeds was studied in this paper. Germination of seeds as well as vitality, cytological evaluation and frequency of chromosomal aberrations for Vicia faba L. seeds sets was also evaluated. The experiment did not show any significant differences between time of seed storage and doses of a radiation. On the other hand tendency of improvement in vitality from oldest to youngest seed sets and from lowest to highest doses of a radiation was more uniform. The wide variety of particular results still made most of comparisons between doses inside of a particular seed set insignificant. We may confirm that with younger seeds sets their vitality improved clearly up to a control level.

  3. Bidirectional Hebbian Plasticity Induced by Low-Frequency Stimulation in Basal Dendrites of Rat Barrel Cortex Layer 5 Pyramidal Neurons.

    Science.gov (United States)

    Díez-García, Andrea; Barros-Zulaica, Natali; Núñez, Ángel; Buño, Washington; Fernández de Sevilla, David

    2017-01-01

    According to Hebb's original hypothesis (Hebb, 1949), synapses are reinforced when presynaptic activity triggers postsynaptic firing, resulting in long-term potentiation (LTP) of synaptic efficacy. Long-term depression (LTD) is a use-dependent decrease in synaptic strength that is thought to be due to synaptic input causing a weak postsynaptic effect. Although the mechanisms that mediate long-term synaptic plasticity have been investigated for at least three decades not all question have as yet been answered. Therefore, we aimed at determining the mechanisms that generate LTP or LTD with the simplest possible protocol. Low-frequency stimulation of basal dendrite inputs in Layer 5 pyramidal neurons of the rat barrel cortex induces LTP. This stimulation triggered an EPSP, an action potential (AP) burst, and a Ca 2+ spike. The same stimulation induced LTD following manipulations that reduced the Ca 2+ spike and Ca 2+ signal or the AP burst. Low-frequency whisker deflections induced similar bidirectional plasticity of action potential evoked responses in anesthetized rats. These results suggest that both in vitro and in vivo similar mechanisms regulate the balance between LTP and LTD. This simple induction form of bidirectional hebbian plasticity could be present in the natural conditions to regulate the detection, flow, and storage of sensorimotor information.

  4. Bidirectional Hebbian Plasticity Induced by Low-Frequency Stimulation in Basal Dendrites of Rat Barrel Cortex Layer 5 Pyramidal Neurons

    Science.gov (United States)

    Díez-García, Andrea; Barros-Zulaica, Natali; Núñez, Ángel; Buño, Washington; Fernández de Sevilla, David

    2017-01-01

    According to Hebb's original hypothesis (Hebb, 1949), synapses are reinforced when presynaptic activity triggers postsynaptic firing, resulting in long-term potentiation (LTP) of synaptic efficacy. Long-term depression (LTD) is a use-dependent decrease in synaptic strength that is thought to be due to synaptic input causing a weak postsynaptic effect. Although the mechanisms that mediate long-term synaptic plasticity have been investigated for at least three decades not all question have as yet been answered. Therefore, we aimed at determining the mechanisms that generate LTP or LTD with the simplest possible protocol. Low-frequency stimulation of basal dendrite inputs in Layer 5 pyramidal neurons of the rat barrel cortex induces LTP. This stimulation triggered an EPSP, an action potential (AP) burst, and a Ca2+ spike. The same stimulation induced LTD following manipulations that reduced the Ca2+ spike and Ca2+ signal or the AP burst. Low-frequency whisker deflections induced similar bidirectional plasticity of action potential evoked responses in anesthetized rats. These results suggest that both in vitro and in vivo similar mechanisms regulate the balance between LTP and LTD. This simple induction form of bidirectional hebbian plasticity could be present in the natural conditions to regulate the detection, flow, and storage of sensorimotor information. PMID:28203145

  5. Frequency-Specific, Binaural Stimulation of Students with Reading and Spelling Difficulties.

    Science.gov (United States)

    Johansen, Kjeld

    A study examined the hearing of learning disabled students (such as dyslexics) in an attempt to classify, identify, and design auditory stimulation procedures. Subjects, 40 students from seventh-grade classes and 40 volunteers (ages 9 to 23) with reading and spelling difficulties, were given listening tests. Results indicated that many of the…

  6. Extending the ICRF to Higher Radio Frequencies: 24 and 43 GHz Astrometry

    Science.gov (United States)

    Jacobs, Christopher S.; Charlot, Patrick; Fomalont, Ed B.; Gordon, David; Lanyi, Gabor E.; Ma, Chopo; Naudet, Charles J.; Sovers, Ojars J.; Zhang, Liwei D.; Kq VLBI Survey Collaboration

    2004-06-01

    Celestial reference frames have been constructed at K-band (24 GHz) and Q-band (43 GHz) based on VLBI astrometric survey observations of active galactic nuclei. Five VLBA observing sessions covered the full 24 hours of right ascension and declinations down to -44°. K-band's 230 sources have median formal position uncertainties of 150 and 290 μas in α cos δ and δ, respectively; the corresponding uncertainties for 132 Q-band sources are 215 and 360 μas, respectively. K-band weighted RMS (WRMS) residuals were 33 ps and 48 fs/s in delay and rate, respectively. Comparison of the K-band frame to the S/X-band ICRF shows WRMS agreement of 330 and 590 μas in α cos δ and δ, respectively. The motivations for extending the ICRF to higher frequencies are to use more compact sources to construct a more stable frame, to provide phase calibrators, and to support spacecraft navigation at Ka-band.

  7. Higher Eating Frequency Does Not Decrease Appetite in Healthy Adults12

    Science.gov (United States)

    Perrigue, Martine M; Drewnowski, Adam; Wang, Ching-Yun; Neuhouser, Marian L

    2016-01-01

    Background: Consumption of small, frequent meals is suggested as an effective approach to control appetite and food intake and might be a strategy for weight loss or healthy weight maintenance. Despite much speculation on the topic, scientific evidence is limited to support such a relation in the absence of changes to diet composition. Objective: We examined the effects of high compared with low eating frequency (EF) on self-reported appetite as a secondary outcome in a controlled trial. Methods: We conducted a randomized, crossover intervention trial in 12 participants (4 men, 8 women) who completed 2 isocaloric 3-wk intervention phases of low EF (3 eating occasions/d) compared with high EF (8 eating occasions/d). On the last morning of each study phase, participants completed a 4-h appetite testing session. During the appetite testing session, participants completing the low EF phase consumed a meal at 0800. Participants completing the high EF intervention consumed the same meal spread evenly over 2 eating occasions at 0800 and 1030. Standardized ratings of hunger, desire to eat, fullness, thirst, and nausea were completed every 30 min with the use of paper-and-pencil semianchored 100-mm visual analog scales. A composite appetite score was calculated as the mean of hunger, desire to eat, and the inverse of fullness (calculated as 100-fullness rating). Linear regression analysis compared ratings between low EF and high EF conditions. Results: The mean composite appetite score was higher in the high EF condition for the total testing period (baseline through 1200) (P appetite. This trial was registered at clinicaltrials.gov as NCT02548026. PMID:26561409

  8. The frequency of genotypes for the SNP Ser/Ser in the studied population of Albanian women is higher in the Balkan region

    Directory of Open Access Journals (Sweden)

    Zafer Gashi

    2016-08-01

    Full Text Available In women undergoing natural cycles, just one oocyte is usually selected for ovulation, yet routine clinical techniques to support the development of multiple follicles using additional gonadotrophins result in numerous ovulations. Several parameters have been postulated as predictors of ovarian response (inhibin B, 17-β-estradiol and antiMüllerian hormone. Nevertheless, the FSH level on the day 3 of menstrual cycle remains, the most widely used biomarker due to its low cost, although, the genetic background of individuals seems to determine the response of patients to rFSH stimulation better than the stimulation design. Consequently, the variants of FSHR were explored and they may be involved in the role of FSH receptor in mediated signal transduction and with ovarian response in infertile women submitted to ovarian stimulation. In this study we examined, for the first time, the prevalence of genotype variants Asn680Ser in population Albanian women from Kosovo Dukagjin region who took part in IVF / ICSI program. The frequencies of the Asn680Ser genotype variants were as follows: Asn/Asn 22.1%, Asn/Ser 47.1%, and Ser/Ser 30.8%, respectively (Table 1. bE2 levels between the three genotype variants showed slight but statistically significant difference (p= 0.0308. No difference was also found between the genotype groups either in terms of AFC, amount of the FSH required for ovulation induction, stimulation length days, number of dominant follicles, oocyte retrieval number or endometrial thickness (Table 2. BMI was significantly higher in the Ser/Ser group as compared to those from the Asn/Ser or the Asn/Asn group (p= 0.0010 (Table 2. In the study population of Albanian women Dukagjin region of Kosovo had a higher incidence of Ser / SER genotype compared to Asn / Asn genotype. Our research results in the Albanian population differ from published data for other ethnic groups in the Balkans.

  9. Low-frequency transcranial magnetic stimulation over left dorsal premotor cortex improves the dynamic control of visuospatially cued actions

    DEFF Research Database (Denmark)

    Ward, Nick S; Bestmann, Sven; Hartwigsen, Gesa

    2010-01-01

    Left rostral dorsal premotor cortex (rPMd) and supramarginal gyrus (SMG) have been implicated in the dynamic control of actions. In 12 right-handed healthy individuals, we applied 30 min of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) over left rPMd to investigate...... the involvement of left rPMd and SMG in the rapid adjustment of actions guided by visuospatial cues. After rTMS, subjects underwent functional magnetic resonance imaging while making spatially congruent button presses with the right or left index finger in response to a left- or right-sided target. Subjects were...... that left rPMd and SMG-AIP contribute toward dynamic control of actions and demonstrate that low-frequency rTMS can enhance functional coupling between task-relevant brain regions and improve some aspects of motor performance....

  10. Effect of low frequency rTMS stimulation over lateral cerebellum: a FDG PET study

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Eun Jin; Cho, Sang Soo; Bang, Soong Ae; Park, Hyun Soo; Kim, Sang Eun [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2007-07-01

    Several lines of evidence suggested the involvement of cerebellum in cognitive function as well as motor function. Because of the measurement difficulty of functional connectivity, little is known about the underlying mechanism involvement of cerebellum in motor and cognitive function in living human brain. To understand the role of cerebellum within the neural network, we investigated the changes of neuronal activity elicited by the cerebellar repetitive transcranial magnetic stimulation (rTMS). 11 right-handed normal volunteers (age: 23.4{+-}2.5 y;6 males) were studied with FDG PET under two conditions; sham and 1Hz rTMS over left lateral cerebellum. With 10 min inter-block interval, three blocks of rTMS were started with the intravenous injection of [18F]FDG. In each block, 5min rTMS were delivered with an intensity of 90% of the resting motor threshold (RMT). Sham rTMS was delivered with same protocol but the coil was positioned perpendicular to the target area with 50% RMT. PET scans were acquired immediately after the rTMS stimulation. Sham and 1Hz rTMS images compared using paired t-test with SPM2. Inhibited neuronal activity compare to the sham condition were revealed in the stimulated left lateral cerebellum and orbitofrontal gyrus and right motor related areas (S1, SMA and posterior parietal cortex). While enhanced neuronal activity compare to the sham condition were revealed in the bilateral inferior frontal gyri including Broca's area and superior temporal gyrus including primary auditory cortex. Bilateral middle temporal, left precentral and right middle occipital gyri were also showed enhanced neuronal activity. This result showed that rTMS over left lateral cerebellum modulate direct vicinity of the targeted region and a large network of remote interconnected contralateral motor and ipsilateral language related brain regions. Present result provide evidence that cerebellum may contribute to language related cognitive function as well as motor

  11. Effect of low frequency rTMS stimulation over lateral cerebellum: a FDG PET study

    International Nuclear Information System (INIS)

    Yoon, Eun Jin; Cho, Sang Soo; Bang, Soong Ae; Park, Hyun Soo; Kim, Sang Eun

    2007-01-01

    Several lines of evidence suggested the involvement of cerebellum in cognitive function as well as motor function. Because of the measurement difficulty of functional connectivity, little is known about the underlying mechanism involvement of cerebellum in motor and cognitive function in living human brain. To understand the role of cerebellum within the neural network, we investigated the changes of neuronal activity elicited by the cerebellar repetitive transcranial magnetic stimulation (rTMS). 11 right-handed normal volunteers (age: 23.4±2.5 y;6 males) were studied with FDG PET under two conditions; sham and 1Hz rTMS over left lateral cerebellum. With 10 min inter-block interval, three blocks of rTMS were started with the intravenous injection of [18F]FDG. In each block, 5min rTMS were delivered with an intensity of 90% of the resting motor threshold (RMT). Sham rTMS was delivered with same protocol but the coil was positioned perpendicular to the target area with 50% RMT. PET scans were acquired immediately after the rTMS stimulation. Sham and 1Hz rTMS images compared using paired t-test with SPM2. Inhibited neuronal activity compare to the sham condition were revealed in the stimulated left lateral cerebellum and orbitofrontal gyrus and right motor related areas (S1, SMA and posterior parietal cortex). While enhanced neuronal activity compare to the sham condition were revealed in the bilateral inferior frontal gyri including Broca's area and superior temporal gyrus including primary auditory cortex. Bilateral middle temporal, left precentral and right middle occipital gyri were also showed enhanced neuronal activity. This result showed that rTMS over left lateral cerebellum modulate direct vicinity of the targeted region and a large network of remote interconnected contralateral motor and ipsilateral language related brain regions. Present result provide evidence that cerebellum may contribute to language related cognitive function as well as motor control

  12. Stimulation of Protein Expression Through the Harmonic Resonance of Frequency-Specific Music.

    Science.gov (United States)

    Orhan, Ibrahim Y; Gulbahar, Burak A

    2016-12-01

    The use of specific frequencies for specific individual amino acids may increase the potential energy of protein molecules in the medium [1]. The resonance would also increase the movement of particles in the cytosol, increasing the collisions necessary for the conduction of protein expression. The clash of two waves that share frequencies will exhibit an increase in energy through an increase in amplitude [2]. The increase in energy would in turn increase the number of collisions forming the tRNA-amino acid, increasing the amino acid acquiry for ribosomes to improve intracellular efficiency in gene expression. To test the hypothesis, Red Fluorescent Protein (RFP) in transformated BL-21 strains of E. coli and p53 protein of MCF-7 were examined after exposure to sounds of specific frequencies. Through the exposure of the experimental systems to a sequence of sounds that match the frequencies of specific amino acids, the levels of RFP exhibition respective to the control groups in the bacterial medium increased two-fold in terms of RFU. The experiments that targeted the p53 protein with the 'music' showed a decrease in the cell prevalence in the MCF-7 type breast cancer cells by 28%, by decreasing the speed of tumour formation. Exposure to 'music' that was designed through assigning a musical note for every single one of the twenty unique amino acids, produced both an analytical and a visible shift in protein synthesis, making it as potential tool for reducing procedural time uptake.

  13. The effects of low frequency electrical stimulation on satellite cell activity in rat skeletal muscle during hindlimb suspension

    Directory of Open Access Journals (Sweden)

    Zhang Hong-Yu

    2010-11-01

    Full Text Available Abstract Background The ability of skeletal muscle to grow and regenerate is dependent on resident stem cells called satellite cells. It has been shown that chronic hindlimb unloading downregulates the satellite cell activity. This study investigated the role of low-frequency electrical stimulation on satellite cell activity during a 28 d hindlimb suspension in rats. Results Mechanical unloading resulted in a 44% reduction in the myofiber cross-sectional area as well as a 29% and 34% reduction in the number of myonuclei and myonuclear domains, respectively, in the soleus muscles (P vs the weight-bearing control. The number of quiescent (M-cadherin+, proliferating (BrdU+ and myoD+, and differentiated (myogenin+ satellite cells was also reduced by 48-57% compared to the weight-bearing animals (P P Conclusion This study shows that electrical stimulation partially attenuated the decrease in muscle size and satellite cells during hindlimb unloading. The causal relationship between satellite cell activation and electrical stimulation remain to be established.

  14. Partial fast-to-slow conversion of regenerating rat fast-twitch muscle by chronic low-frequency stimulation.

    Science.gov (United States)

    Pette, Dirk; Sketelj, Janez; Skorjanc, Dejan; Leisner, Elmi; Traub, Irmtrud; Bajrović, Fajko

    2002-01-01

    Chronic low-frequency stimulation (CLFS) of rat fast-twitch muscles induces sequential transitions in myosin heavy chain (MHC) expression from MHCIIb --> MHCIId/x --> MHCIIa. However, the 'final' step of the fast-to-slow transition, i.e., the upregulation of MHCI, has been observed only after extremely long stimulation periods. Assuming that fibre degeneration/regeneration might be involved in the upregulation of slow myosin, we investigated the effects of CLFS on extensor digitorum longus (EDL) muscles regenerating after bupivacaine-induced fibre necrosis. Normal, non-regenerating muscles responded to both 30- and 60-day CLFS with fast MHC isoform transitions (MHCIIb --> MHCIId --> MHCIIa) and only slight increases in MHCI. CLFS of regenerating EDL muscles caused similar transitions among the fast isoforms but, in addition, caused significant increases in MHCI (to approximately 30% relative concentration). Stimulation periods of 30 and 60 days induced similar changes in the regenerating bupivacaine-treated muscles, indicating that the upregulation of slow myosin was restricted to regenerating fibres, but only during an early stage of regeneration. These results suggest that satellite cells and/or regenerating fast rat muscle fibres are capable of switching directly to a slow program under the influence of CLFS and, therefore, appear to be more malleable than adult fibres.

  15. Low- vs high- frequency Repetitive Transcranial Magnetic Stimulation as an add-on treatment for refractory depression

    Directory of Open Access Journals (Sweden)

    julien eeche

    2012-03-01

    Full Text Available Objectives: Repetitive transcranial magnetic stimulation (rTMS seems to be effective as an antidepressant treatment, however, some confusion remain about the best parameters to apply and the efficacy of its association with pharmacological antidepressant treatments.Method: In a single blind randomized study14 patients with unipolar resistant depression to one antidepressant treatment were enrolled to received, in combination with venlafaxine (150 mg, either 20 sessions of 10Hz rTMS (2 000 pulses per session applied over le left dorsolateral prefrontal cortex (DLPFC or 20 sessions of 1 Hz rTMS (120 stimulations per sessions applied over the right DLPFC. Results: A similar antidepressant effect was observed in both groups with a comparable antidepressant delay of action (2 weeks and a comparable number of patients in remission after 4 weeks of daily rTMS sessions (66 vs 50 %.Conclusion: Low- and high- frequency rTMS seem to be effective as an add-on treatment to venlafaxine in pharmacological refractory major depression. Due to its short duration and its safety, low frequency rTMS may be a useful alternative treatment for patients with refractory depression.

  16. Modulation of the Left Prefrontal Cortex with High Frequency Repetitive Transcranial Magnetic Stimulation Facilitates Gait in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Amer M. Burhan

    2015-01-01

    Full Text Available Multiple Sclerosis (MS is a chronic central nervous system (CNS demyelinating disease. Gait abnormalities are common and disabling in patients with MS with limited treatment options available. Emerging evidence suggests a role of prefrontal attention networks in modulating gait. High-frequency repetitive transcranial magnetic stimulation (rTMS is known to enhance cortical excitability in stimulated cortex and its correlates. We investigated the effect of high-frequency left prefrontal rTMS on gait parameters in a 51-year-old Caucasian male with chronic relapsing/remitting MS with residual disabling attention and gait symptoms. Patient received 6 Hz, rTMS at 90% motor threshold using figure of eight coil centered on F3 location (using 10-20 electroencephalography (EEG lead localization system. GAITRite gait analysis system was used to collect objective gait measures before and after one session and in another occasion three consecutive daily sessions of rTMS. Two-tailed within subject repeated measure t-test showed significant enhancement in ambulation time, gait velocity, and cadence after three consecutive daily sessions of rTMS. Modulating left prefrontal cortex excitability using rTMS resulted in significant change in gait parameters after three sessions. To our knowledge, this is the first report that demonstrates the effect of rTMS applied to the prefrontal cortex on gait in MS patients.

  17. Effects of High Frequency Repeated Transcranial Magnetic Stimulation and Continuous Theta Burst Stimulation on Gambling Reinforcement, Delay Discounting, and Stroop Interference in Men with Pathological Gambling.

    Science.gov (United States)

    Zack, Martin; Cho, Sang Soo; Parlee, Jennifer; Jacobs, Mark; Li, Crystal; Boileau, Isabelle; Strafella, Antonio

    Repeated transcranial magnetic stimulation (rTMS) can reduce cravings and improve cognitive function in substance dependent individuals. Whether these benefits extend to individuals with pathological gambling (PG) is unclear. High-frequency rTMS of the medial prefrontal cortex (PFC) and continuous theta burst stimulation (cTBS) of the right dorsolateral PFC can reduce impulsive choice in healthy volunteers. This study aimed to assess the effects of these two protocols on gambling reinforcement and related responses in otherwise healthy men with PG. Participants (n = 9) underwent active or sham treatments at weekly intervals in a repeated-measures, Latin square design. Subjective and physiological responses were assessed before and after a 15-min slot machine game on each session. Delay discounting and Stroop tasks measured post-game impulsive choice and attentional control. Multivariate analysis of covariance, controlling for winnings on the slot machine under each treatment, found that rTMS reduced the post-game increase in Desire to Gamble; cTBS reduced amphetamine-like effects, and decreased diastolic blood pressure. Treatment had no significant univariate effects on bet size or speed of play in the game; however, a multivariate effect for the two indices suggested that treatment decreased behavioral activation. Neither treatment reduced impulsive choice, while both treatments increased Stroop interference. rTMS and cTBS can reduce gambling reinforcement in non-comorbid men with PG. Separate processes appear to mediate gambling reinforcement and betting behavior as against delay discounting and Stroop interference. Interventions that modify risky as opposed to temporal aspects of decision making may better predict therapeutic response in PG. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. The effect of low frequency stimulation of the pedunculopontine tegmental nucleus on basal ganglia in a rat model of Parkinson's disease.

    Science.gov (United States)

    Park, Eunkyoung; Song, Inho; Jang, Dong Pyo; Kim, In Young

    2014-08-08

    The pedunculopontine nucleus (PPN) has recently been introduced as an alternative target to the subthalamic nucleus (STN) or globus pallidus internus (GPi) for the treatment of advanced Parkinson's disease with severe and medically intractable axial symptoms such as gait and postural impairment. However, it is little known about how electrical stimulation of the PPN affects control of neuronal activities between the PPN and basal ganglia. We examined how low frequency stimulation of the pedunculopontine tegmental nucleus (PPTg) affects control of neuronal activities between the PPN and basal ganglia in 6-OHDA lesioned rats. In order to identify the effect of low frequency stimulation on the PPTg, neuronal activity in both the STN and substantia nigra par reticulata (SNr) were recorded and subjected to quantitative analysis, including analysis of firing rates and firing patterns. In this study, we found that the firing rates of the STN and SNr were suppressed during low frequency stimulation of the PPTg. However, the firing pattern, in contrast to the firing rate, did not exhibit significant changes in either the STN or SNr of 6-OHDA lesioned rats during low frequency stimulation of the PPTg. In addition, we also found that the firing rate of STN and SNr neurons displaying burst and random pattern were decreased by low frequency stimulation of PPTg, while the neurons displaying regular pattern were not affected. These results indicate that low frequency stimulation of the PPTg affects neuronal activity in both the STN and SNr, and may represent electrophysiological efficacy of low frequency PPN stimulation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Fixed-site high-frequency transcutaneous electrical nerve stimulation for treatment of chronic low back and lower extremity pain

    Directory of Open Access Journals (Sweden)

    Gozani SN

    2016-06-01

    Full Text Available Shai N Gozani NeuroMetrix, Inc., Waltham, MA, USA Objective: The objective of this study was to determine if fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS is effective in treating chronic low back and lower extremity pain. Background: Transcutaneous electrical nerve stimulation is widely used for treatment of chronic pain. General-purpose transcutaneous electrical nerve stimulation devices are designed for stimulation anywhere on the body and often cannot be used while the user is active or sleeping. FS-TENS devices are designed for placement at a pre-determined location, which enables development of a wearable device for use over extended time periods. Methods: Study participants with chronic low back and/or lower extremity pain self-administered an FS-TENS device for 60 days. Baseline, 30-, and 60-day follow-up data were obtained through an online questionnaire. The primary outcome measure was the patient global impression of change. Pain intensity and interference were assessed using the Brief Pain Inventory. Changes in use of concomitant pain medications were evaluated with a single-item global self-rating. Results: One hundred and thirty participants were enrolled, with 88 completing the 60-day follow-up questionnaire. Most participants (73.9% were 50 years of age or older. At baseline, low back pain was identified by 85.3%, lower extremity pain by 71.6%, and upper extremity pain by 62.5%. Participants reported widespread pain, at baseline, with a mean of 3.4 (standard deviation 1.1 pain sites. At the 60-day follow-up, 80.7% of participants reported that their chronic pain had improved and they were classified as responders. Baseline characteristics did not differentiate non-responders from responders. There were numerical trends toward reduced pain interference with walking ability and sleep, and greater pain relief in responders. There was a large difference in use of concomitant pain medications, with 80

  20. The Role of Low-frequency TRANS-orbital Magnetic Stimulation in Normalization of Intraocular Pressure in Patients with Primary Open-angle Glaucoma

    Directory of Open Access Journals (Sweden)

    I. A. Makarov

    2016-01-01

    Full Text Available Purpose. Assessment of the effectiveness of low-frequency magnetic therapy on the dynamics of intraocular pressure in the treatment of primary and uncompensated medical means of open-angle glaucoma. Patients and Methods. 46 patients with uncompensated open-angle glaucoma. The first group: 24 patients (42 eyes with open-angle glaucoma (I, II, III stages during 2–13 years. The second group: 22 patients (22 eyes with newly diagnosed elevated intraocular pressure in one eye. The age of patients ranged from 43 to 59 years. Treatment included antiglaucoma hypotensive eye drops and TRANS-orbital magnetic stimulation on the domestic device“Polus-2”. Results. Intraocular pressure before treatment ranged from 25 to 32 mm Hg. (average of 28.9±1.4 mm Hg. in the first group . After magnetic stimulation IOP decreased within 2–5 days in all patients to 18 to 21 mm Hg (average of 17.9±1.1 mm Hg, reaching values “pressure goal.” Second group: in the primary treatment in patients IOP was 28–39 mm Hg (average of 32.6±1.8 mm Hg on one of the eyes. IOP decreased to 16–21 mm Hg in the period from 3 to 9 days in all patients of study group after daily magnetic stimulation and instillation of xalatan and timolol. In the control subgroup of patients with uncompensated openangle glaucoma loweringof the IOP to “pressure goal,” noted only in 7 patients (70,0% 11–14 days after instillation of anti-hypertensive glaucoma eye drops only. Conclusion. Low-frequency TRANS-orbital magnetic stimulation in enhanced hypotensive effect antiglaucomatous eye drops and makes it easier to achieve compensation of IOP to values “pressure goals” in patients with uncompensated open-angle glaucoma. The marked dependence of the efficiency of reduction of IOP from biotropic parameters of the magnetic field. The pulsed mode with a higher amplitude value of the magnetic induction has a more pronounced effect and makes it easier to achieve the reduction of IOP.

  1. Effective treatment of narcolepsy-like symptoms with high-frequency repetitive transcranial magnetic stimulation: A case report.

    Science.gov (United States)

    Lai, Jian-Bo; Han, Mao-Mao; Xu, Yi; Hu, Shao-Hua

    2017-11-01

    Narcolepsy is a rare sleep disorder with disrupted sleep-architecture. Clinical management of narcolepsy lies dominantly on symptom-driven pharmacotherapy. The treatment role of repetitive transcranial magnetic stimulation (rTMS) for narcolepsy remains unexplored. In this paper, we present a case of a 14-year-old young girl with excessive daytime sleepiness (EDS), cataplexy and hypnagogic hallucinations. After excluding other possible medical conditions, this patient was primarily diagnosed with narcolepsy. The patient received 25 sessions of high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC). The symptoms of EDS and cataplexy significantly improved after rTMS treatment. Meanwhile, her score in the Epworth sleep scale (ESS) also remarkably decreased. This case indicates that rTMS may be selected as a safe and effective alternative strategy for treating narcolepsy-like symptoms. Well-designed researches are warranted in future investigations on this topic.

  2. Low-frequency electrical stimulation enhances the effectiveness of phenobarbital on GABAergic currents in hippocampal slices of kindled rats.

    Science.gov (United States)

    Asgari, Azam; Semnanian, Saeed; Atapour, Nafiseh; Shojaei, Amir; Moradi-Chameh, Homeira; Ghafouri, Samireh; Sheibani, Vahid; Mirnajafi-Zadeh, Javad

    2016-08-25

    Low frequency stimulation (LFS) has been proposed as a new approach in the treatment of epilepsy. The anticonvulsant mechanism of LFS may be through its effect on GABAA receptors, which are the main target of phenobarbital anticonvulsant action. We supposed that co-application of LFS and phenobarbital may increase the efficacy of phenobarbital. Therefore, the interaction of LFS and phenobarbital on GABAergic inhibitory post-synaptic currents (IPSCs) in kindled and control rats was investigated. Animals were kindled by electrical stimulation of basolateral amygdala in a semi rapid manner (12 stimulations/day). The effect of phenobarbital, LFS and phenobarbital+LFS was investigated on GABAA-mediated evoked and miniature IPSCs in the hippocampal brain slices in control and fully kindled animals. Phenobarbital and LFS had positive interaction on GABAergic currents. In vitro co-application of an ineffective pattern of LFS (100 pulses at afterdischarge threshold intensity) and a sub-threshold dose of phenobarbital (100μM) which had no significant effect on GABAergic currents alone, increased the amplitude and area under curve of GABAergic currents in CA1 pyramidal neurons of hippocampal slices significantly. Interestingly, the sub-threshold dose of phenobarbital potentiated the GABAergic currents when applied on the hippocampal slices of kindled animals which received LFS in vivo. Post-synaptic mechanisms may be involved in observed interactions. Obtained results implied a positive interaction between LFS and phenobarbital through GABAA currents. It may be suggested that a combined therapy of phenobarbital and LFS may be a useful manner for reinforcing the anticonvulsant action of phenobarbital. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  3. Effectiveness of high-frequency transcutaneous electrical nerve stimulation at tender points as adjuvant therapy for patients with fibromyalgia.

    Science.gov (United States)

    Carbonario, F; Matsutani, L A; Yuan, S L K; Marques, A P

    2013-04-01

    Fibromyalgia is a chronic pain syndrome associated with sleep disorders, fatigue and psychological symptoms. Combinations therapies, such as electrotherapy and therapeutic exercises have been used in the clinical practice. To assess the efficacy of high-frequency transcutaneous electrical nerve stimulation (TENS) as an adjuvant therapy to aerobic and stretching exercises, for the treatment of fibromyalgia. Controlled clinical trial. Unit of rehabilitation of a public hospital. Twenty-eight women aged 52.4±7.5 years, with fibromyalgia. A visual analogue scale measured pain intensity; tender points pain threshold, by dolorimetry; and quality of life, by the Fibromyalgia Impact Questionnaire. All subjects participated in an eight-week program consisting of aerobic exercises, followed by static stretching of muscle chains. In TENS group, high-frequency (150 Hz) was applied on bilateral tender points of trapezium and supraspinatus. TENS group had a greater pain reduction (mean change score=-2.0±2.9 cm) compared to Without TENS group (-0.7±3.7 cm). There was a difference between mean change scores of each group for pain threshold (right trapezium: 0.2±1 kg/cm² in TENS group and -0.2±1.2 kg/cm² in Without TENS group). In the evaluation of clinically important changes, patients receiving TENS had relevant improvement of pain, work performance, fatigue, stiffness, anxiety and depression compared to those not receiving TENS. It has suggested that high-frequency TENS as an adjuvant therapy is effective in relieving pain, anxiety, fatigue, stiffness, and in improving ability to work of patients with fibromyalgia. High-frequency TENS may be used as a short-term complementary treatment of fibromyalgia.

  4. The double-resonance enhancement of stimulated low-frequency Raman scattering in silver-capped nanodiamonds

    Science.gov (United States)

    Baranov, A. N.; Butsen, A. V.; Ionin, A. A.; Ivanova, A. K.; Kuchmizhak, A. A.; Kudryashov, S. I.; Kudryavtseva, A. D.; Levchenko, A. O.; Rudenko, A. A.; Saraeva, I. N.; Strokov, M. A.; Tcherniega, N. V.; Zayarny, D. A.

    2017-09-01

    Hybrid plasmonic-dielectric nano- and (sub)microparticles exhibit magnetic and electrical dipolar Mie-resonances, which makes them useful as efficient basic elements in surface-enhanced spectroscopy, non-linear light conversion and nanoscale light control. We report the stimulated low-frequency Raman scattering (SLFRS) of a nanosecond ruby laser radiation (central wavelength λ = 694.3 nm (full-width at half-maximum ≈ 0.015 cm-1), gaussian 1/e-intensity pulsewidth τ ≈ 20 ns, TEM00-mode pulse energy Emax ≈ 0.3 J) in nanodiamond (R ≈ 120 nm) hydrosols, induced via optomechanical coherent excitation of fundamental breathing eigen-modes, and the two-fold enhancement of SLFRS in Ag-decorated nanodiamonds, characterized by hybrid dipolar resonances of electrical (silver) and magnetic (diamond) nature. Hybrid metal-dielectric particles were prepared by means of nanosecond IR-laser ablation of solid silver target in diamond hydrosols with consecutive Ag-capping of diamonds, and were characterized by scanning electron microscopy, UV-vis, photoluminescence and energy-dispersive X-ray spectroscopy. Intensities of the SLFR-scattered components and their size-dependent spectral shifts were measured in the highly sensitive stimulated scattering regime, indicating the high (≈ 30%) SLFRS conversion efficiency and the resonant character of the scattering species.

  5. A higher meal frequency may be associated with diminished weight loss after bariatric surgery

    OpenAIRE

    RIBEIRO, Angela Gadelha; COSTA, Maria José de Carvalho; FAINTUCH, Joel; DIAS, Maria Carolina Gonçalves

    2009-01-01

    OBJECTIVE: This study aimed to investigate the relationship between meal frequency, the occurrence of vomiting and weight loss among patients submitted to Roux-en-Y gastric bypass up to 9 months after surgery. METHODS: Female patients (n = 80) were followed at 3-month intervals for 9 months. Weight, BMI, 24-hour dietary recall, drug consumption and vomiting episodes were recorded and compared with nutritional outcome. RESULTS: The BMI values at 3, 6 and 9 months were 45.1 ± 9.7, 39.9 ± 7.6 an...

  6. Transcutaneous electrical nerve stimulator of 5000 Hz frequency provides better analgesia than that of 100 Hz frequency in mice muscle pain model

    Directory of Open Access Journals (Sweden)

    Hung-Tsung Hsiao

    2017-04-01

    Full Text Available Transcutaneous electrical nerve stimulators (TENSs have been proved to be effective in muscle pain management for several decades. However, there is no consensus for the optimal TENS program. Previous research demonstrated that a 100 Hz TENS (L-TENS provided better analgesia than a conventional TENS ( 100 Hz TENS with a 100 Hz TENS. We used a 5000 Hz (5 kHz frequency TENS (M-TENS and an L-TENS to compare analgesic effect on a mice skin/muscle incision retraction model. Three groups of mice were used (sham, L-TENS, and M-TENS and applied with different TENS programs on Day 4 after the mice skin/muscle incision retraction model; TENS therapy was continued as 20 min/d for 3 days. Mice analgesic effects were measured via Von Frey microfilaments with the up–down method. After therapy, mice spinal cord dorsal horn and dorsal root ganglion (DRG were harvested for cytokine evaluation (tumor necrosis factor-α and interleukin-1β with the Western blotting method. Our data demonstrated that the M-TENS produced better analgesia than the L-TENS. Cytokine in the spinal cord or DRG all expressed lower than that of the sham group. However, there is no difference in both cytokine levels between TENSs of different frequencies in the spinal cord and DRG. We concluded that the M-TENS produced faster and better mechanical analgesia than the L-TENS in the mice skin/muscle incision retraction model. Those behavior differences were not in accordance with cytokine changes in the spinal cord or DRG.

  7. Adjuvant low-frequency rTMS in treating auditory hallucinations in recent-onset schizophrenia: a randomized controlled study investigating the effect of high-frequency priming stimulation.

    Science.gov (United States)

    Ray, Prasenjit; Sinha, Vinod Kumar; Tikka, Sai Krishna

    2015-01-01

    Repetitive transcranial magnetic stimulation (rTMS) has been found to be effective in reducing frequency and duration of auditory verbal hallucinations (AVH). Priming stimulation, which involves high-frequency rTMS stimulation followed by low-frequency rTMS, has been shown to markedly enhance the neural response to the low-frequency stimulation train. However, this technique has not been investigated in recent onset schizophrenia patients. The aim of this randomized controlled study was to investigate whether the effects of rTMS on AVH can be enhanced with priming rTMS in recent onset schizophrenia patients. Forty recent onset schizophrenia patients completed the study. Patients were randomized over two groups: one receiving low-frequency rTMS preceded by priming and another receiving low-frequency rTMS without priming. Both treatments were directed at the left temporo-parietal region. The severity of AVH and other psychotic symptoms were assessed with the auditory hallucination subscale (AHRS) of the Psychotic Symptom Rating Scales (PSYRATS), the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression (CGI). We found that all the scores of these ratings significantly reduced over time (i.e. baseline through 1, 2, 4 and 6 weeks) in both the treatment groups. We found no difference between the two groups on all measures, except for significantly greater improvement on loudness of AVH in the group with priming stimulation during the follow-ups (F = 2.72; p low-frequency rTMS alone and high-frequency priming of low-frequency rTMS do not elicit significant differences in treatment of overall psychopathology, particularly AVH when given in recent onset schizophrenia patients. Add on priming however, seems to be particularly better in faster reduction in loudness of AVH.

  8. Fixed-site high-frequency transcutaneous electrical nerve stimulation for treatment of chronic low back and lower extremity pain

    Science.gov (United States)

    Gozani, Shai N

    2016-01-01

    Objective The objective of this study was to determine if fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS) is effective in treating chronic low back and lower extremity pain. Background Transcutaneous electrical nerve stimulation is widely used for treatment of chronic pain. General-purpose transcutaneous electrical nerve stimulation devices are designed for stimulation anywhere on the body and often cannot be used while the user is active or sleeping. FS-TENS devices are designed for placement at a pre-determined location, which enables development of a wearable device for use over extended time periods. Methods Study participants with chronic low back and/or lower extremity pain self-administered an FS-TENS device for 60 days. Baseline, 30-, and 60-day follow-up data were obtained through an online questionnaire. The primary outcome measure was the patient global impression of change. Pain intensity and interference were assessed using the Brief Pain Inventory. Changes in use of concomitant pain medications were evaluated with a single-item global self-rating. Results One hundred and thirty participants were enrolled, with 88 completing the 60-day follow-up questionnaire. Most participants (73.9%) were 50 years of age or older. At baseline, low back pain was identified by 85.3%, lower extremity pain by 71.6%, and upper extremity pain by 62.5%. Participants reported widespread pain, at baseline, with a mean of 3.4 (standard deviation 1.1) pain sites. At the 60-day follow-up, 80.7% of participants reported that their chronic pain had improved and they were classified as responders. Baseline characteristics did not differentiate non-responders from responders. There were numerical trends toward reduced pain interference with walking ability and sleep, and greater pain relief in responders. There was a large difference in use of concomitant pain medications, with 80.3% of responders reporting a reduction compared to 11.8% of non

  9. Fixed-site high-frequency transcutaneous electrical nerve stimulation for treatment of chronic low back and lower extremity pain.

    Science.gov (United States)

    Gozani, Shai N

    2016-01-01

    The objective of this study was to determine if fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS) is effective in treating chronic low back and lower extremity pain. Transcutaneous electrical nerve stimulation is widely used for treatment of chronic pain. General-purpose transcutaneous electrical nerve stimulation devices are designed for stimulation anywhere on the body and often cannot be used while the user is active or sleeping. FS-TENS devices are designed for placement at a pre-determined location, which enables development of a wearable device for use over extended time periods. Study participants with chronic low back and/or lower extremity pain self-administered an FS-TENS device for 60 days. Baseline, 30-, and 60-day follow-up data were obtained through an online questionnaire. The primary outcome measure was the patient global impression of change. Pain intensity and interference were assessed using the Brief Pain Inventory. Changes in use of concomitant pain medications were evaluated with a single-item global self-rating. One hundred and thirty participants were enrolled, with 88 completing the 60-day follow-up questionnaire. Most participants (73.9%) were 50 years of age or older. At baseline, low back pain was identified by 85.3%, lower extremity pain by 71.6%, and upper extremity pain by 62.5%. Participants reported widespread pain, at baseline, with a mean of 3.4 (standard deviation 1.1) pain sites. At the 60-day follow-up, 80.7% of participants reported that their chronic pain had improved and they were classified as responders. Baseline characteristics did not differentiate non-responders from responders. There were numerical trends toward reduced pain interference with walking ability and sleep, and greater pain relief in responders. There was a large difference in use of concomitant pain medications, with 80.3% of responders reporting a reduction compared to 11.8% of non-responders. FS-TENS is a safe and effective

  10. Recovery of supraspinal control of leg movement in a chronic complete flaccid paraplegic man after continuous low-frequency pelvic nerve stimulation and FES-assisted training

    DEFF Research Database (Denmark)

    Possover, Marc; Forman, Axel

    2017-01-01

    INTRODUCTION: More than 30 years ago, functional electrical stimulation (FES) was developed as an orthotic system to be used for rehabilitation for SCI patients. In the present case report, FES-assisted training was combined with continuous low-frequency stimulation of the pelvic somatic nerves...... in a SCI patient. CASE PRESENTATION: We report on unexpected findings in a 41-year-old man with chronic complete flaccid paraplegia, since he was 18 years old, who underwent spinal stem cell therapy and a laparoscopic implantation of neuroprosthesis (LION procedure) in the pelvic lumbosacral nerves....... The patient had complete flaccid sensomotoric paraplegia T12 as a result of a motor vehicle accident in 1998. In June 2011, he underwent a laparoscopic implantation of stimulation electrodes to the sciatic and femoral nerves for continuous low-frequency electrical stimulation and functional electrical...

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

    Directory of Open Access Journals (Sweden)

    Leticia Verdugo-Diaz

    2017-01-01

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

  12. Spinal Cord Stimulation for Treating Chronic Pain: Reviewing Preclinical and Clinical Data on Paresthesia-Free High-Frequency Therapy.

    Science.gov (United States)

    Chakravarthy, Krishnan; Richter, Hira; Christo, Paul J; Williams, Kayode; Guan, Yun

    2018-01-01

    Traditional spinal cord stimulation (SCS) requires that paresthesia overlaps chronic painful areas. However, the new paradigm high-frequency SCS (HF-SCS) does not rely on paresthesia. A review of preclinical and clinical studies regarding the use of paresthesia-free HF-SCS for various chronic pain states. We reviewed available literatures on HF-SCS, including Nevro's paresthesia-free ultra high-frequency 10 kHz therapy (HF10-SCS). Data sources included relevant literature identified through searches of PubMed, MEDLINE/OVID, and SCOPUS, and manual searches of the bibliographies of known primary and review articles. The primary goal is to describe the present developing conceptions of preclinical mechanisms of HF-SCS and to review clinical efficacy on paresthesia-free HF10-SCS for various chronic pain states. HF10-SCS offers a novel pain reduction tool without paresthesia for failed back surgery syndrome and chronic axial back pain. Preclinical findings indicate that potential mechanisms of action for paresthesia-free HF-SCS differ from those of traditional SCS. To fully understand and utilize paresthesia-free HF-SCS, mechanistic study and translational research will be very important, with increasing collaboration between basic science and clinical communities to design better trials and optimize the therapy based on mechanistic findings from effective preclinical models and approaches. Future research in these vital areas may include preclinical and clinical components conducted in parallel to optimize the potential of this technology. © 2017 International Neuromodulation Society.

  13. Frequency-domain interferometer simulation with higher-order spatial modes

    International Nuclear Information System (INIS)

    Freise, A; Heinzel, G; Lueck, H; Schilling, R; Willke, B; Danzmann, K

    2004-01-01

    FINESSE is a software simulation allowing one to compute the optical properties of laser interferometers used by interferometric gravitational-wave detectors today. This fast and versatile tool has already proven to be useful in the design and commissioning of gravitational-wave detectors. The basic algorithm of FINESSE numerically computes the light amplitudes inside an interferometer using Hermite-Gauss modes in the frequency domain. In addition, FINESSE provides a number of commands for easily generating and plotting the most common signals including power enhancement, error and control signals, transfer functions and shot-noise-limited sensitivities. Among the various simulation tools available to the gravitational wave community today, FINESSE provides an advanced and versatile optical simulation based on a general analysis of user-defined optical setups and is quick to install and easy to use

  14. [Impacts of the low-frequency electric stimulation at the acupoints on the content of plasma 5-HT and NE in the patients with post-stroke insomnia].

    Science.gov (United States)

    Tang, Lei; Ma, Chaoyan; You, Fei; Ding, Lin

    2015-08-01

    To compare the clinical efficacy on post-stroke insomnia between the low-frequency electric stimulation at the acupoints and the conventional western medication in the patients so as to explore the effect mechanism. One hundred and twenty patients of post-stroke insomnia were randomized into a low-frequency electric stimulation group, a medication group and a placebo group, 40 cases in each one. In the low-frequency electric stimulation group, the low-frequency pulse electric apparatus was applied to stimulate Dazhui (GV 14) and Shenshu (BL 23), once every day. The treatment for 15 days made one session and 2 sessions were required. In the medication group, estazolam was taken orally, 1 mg each time; and in the placebo group, the starch capsules were taken, one capsule each time; in the two groups the treatment was adopted before sleep every night, continuously for 15 days as one session, and 2 sessions were required. The levels of plasma 5-hydroxytryptamine (5-HT) and norepinephrine (NE) were compared before and after treatment in the patients of the three groups and: the efficacy was compared. In the placebo group, 1 case was dropped out. The total effective rate was 95. 0% (38/40), 92. 5% (37/40) and 17. 9% (7/39) in the low-frequency electric stimulation group, the medication group and the placebo group respectively. The effects in the low-frequency electric stimulation group and the medication group were better apparently than that in the placebo group (both Plow-frequency electric stimulation group and the medication group (P>0. 05). The levels of plasma 5-HT and NE were not different significantly between before and after treatment in the placebo group. The level of plasma 5-HT was increased (both Plow-frequency electric stimulation group and the medication group. But the differences were not significant between the two groups (P>0. 05). The low-frequency electric stimlaton a the acupoints is safe and effective in the treatment of post-stroke insomnia, which

  15. The Influence of Higher Protein Intake and Greater Eating Frequency on Appetite Control in Overweight and Obese Men

    Science.gov (United States)

    Leidy, Heather J.; Armstrong, Cheryl L.H.; Tang, Minghua; Mattes, Richard D.; Campbell, Wayne W.

    2014-01-01

    The purpose of this study was to determine the effects of dietary protein intake and eating frequency on perceived appetite, satiety, and hormonal responses in overweight/obese men. Thirteen men (age 51 ± 4 years; BMI 31.3 ± 0.8 kg/m2) consumed eucaloric diets containing normal protein (79 ± 2 g protein/day; 14% of energy intake as protein) or higher protein (138 ± 3 g protein/day; 25% of energy intake as protein) equally divided among three eating occasions (3-EO; every 4 h) or six eating occasions (6-EO; every 2 h) on four separate days in randomized order. Hunger, fullness, plasma glucose, and hormonal responses were assessed throughout 11 h. No protein × eating frequency interactions were observed for any of the outcomes. Independent of eating frequency, higher protein led to greater daily fullness (P < 0.05) and peptide YY (PYY) concentrations (P < 0.05). In contrast, higher protein led to greater daily ghrelin concentrations (P < 0.05) vs. normal protein. Protein quantity did not influence daily hunger, glucose, or insulin concentrations. Independent of dietary protein, 6-EO led to lower daily fullness (P < 0.05) and PYY concentrations (P < 0.05). The 6-EO also led to lower glucose (P < 0.05) and insulin concentrations (P < 0.05) vs. 3-EO. Although the hunger-related perceived sensations and hormonal responses were conflicting, the fullness-related responses were consistently greater with higher protein intake but lower with increased eating frequency. Collectively, these data suggest that higher protein intake promotes satiety and challenge the concept that increasing the number of eating occasions enhances satiety in overweight and obese men. PMID:20339363

  16. Low frequency geomagnetic field fluctuations at low latitude during the passage of a higher pressure solar wind region

    Directory of Open Access Journals (Sweden)

    U. Villante

    1997-06-01

    Full Text Available The passage of a higher pressure solar wind region at the Earth's orbit marked the onset of low latitude (L=1.6 fluctuations in the frequency range (0.8–5.5 mHz for both the horizontal geomagnetic field components. Spectral peaks mostly occur at the same frequencies as the spectral enhancements which appeared in the long term analysis of experimental measurements from the same station and were tentatively interpreted in terms of ground signatures of global magnetospheric modes. A comparison with simultaneous observations discussed by previous investigations allows us to conclude that the same set of frequencies is enhanced in a wide portion of the Earth's magnetosphere.

  17. An investigation into the effects of frequency-modulated transcutaneous electrical nerve stimulation (TENS) on experimentally-induced pressure pain in healthy human participants.

    Science.gov (United States)

    Chen, Chih-Chung; Johnson, Mark I

    2009-10-01

    Frequency-modulated transcutaneous electrical nerve stimulation (TENS) delivers currents that fluctuate between preset boundaries over a fixed period of time. This study compared the effects of constant-frequency TENS and frequency-modulated TENS on blunt pressure pain in healthy human volunteers. Thirty-six participants received constant-frequency TENS (80 pps), frequency-modulated TENS (20 to 100 pps), and placebo (no current) TENS at a strong nonpainful intensity in a randomized cross-over manner. Pain threshold was taken from the forearm using pressure algometry. There were no statistical differences between constant-frequency TENS and frequency-modulated TENS after 20 minutes (OR = 1.54; CI, 0.29, 8.23, P = 1.0). Both constant-frequency TENS and frequency-modulated TENS were superior to placebo TENS (OR = 59.5, P TENS does not influence hypoalgesia to any greater extent than constant-frequency TENS when currents generate a strong nonpainful paraesthesia at the site of pain. The finding that frequency-modulated TENS and constant-frequency TENS were superior to placebo TENS provides further evidence that a strong yet nonpainful TENS intensity is a prerequisite for hypoalgesia. This study provides evidence that TENS, delivered at a strong nonpainful intensity, increases pain threshold to pressure algometry in healthy participants over and above that seen with placebo (no current) TENS. Frequency-modulated TENS does not increase hypoalgesia to any appreciable extent to that seen with constant-frequency TENS.

  18. A higher meal frequency may be associated with diminished weight loss after bariatric surgery.

    Science.gov (United States)

    Ribeiro, Angela Gadelha; Costa, Maria José de Carvalho; Faintuch, Joel; Dias, Maria Carolina Gonçalves

    2009-01-01

    This study aimed to investigate the relationship between meal frequency, the occurrence of vomiting and weight loss among patients submitted to Roux-en-Y gastric bypass up to 9 months after surgery. Female patients (n = 80) were followed at 3-month intervals for 9 months. Weight, BMI, 24-hour dietary recall, drug consumption and vomiting episodes were recorded and compared with nutritional outcome. The BMI values at 3, 6 and 9 months were 45.1 +/- 9.7, 39.9 +/- 7.6 and 35.4 +/- 8.2 kg/m(2), respectively. The corresponding choleric intakes were 535.6 +/- 295.7, 677.1 +/- 314.7 and 828.6 +/- 398.2 kcal/day, and the numbers of daily meals were 5.0 +/- 2.5, 4.7 +/- 1.8 and 4.9 +/- 1.0, respectively. The peak of vomiting episodes occurred within 6 months; however, patients tolerated this complication despite its high prevalence. A significant negative correlation between weight loss and diet fractioning, but not vomiting, was observed throughout the entire postoperative period (P = 0.001). 1) Frequent small meals were associated with a reduction in weight loss after gastric bypass and a decrease in vomiting episodes at 6 months, and 2) vomiting did not interfere with nutritional outcome. Unless required because of vomiting or other reasons, multiple small meals may not be advantageous after such intervention.

  19. Sinusoidal oscillators with lower gain requirements at higher frequencies based on an explicit tanh(x) nonlinearity

    KAUST Repository

    Elwakil, Ahmed S.

    2009-04-28

    Two novel sinusoidal oscillator structures with an explicit tanh(x) nonlinearity are proposed. The oscillators have the attractive feature: the higher the operating frequency, the lower the necessary gain required to start oscillations. A nonlinear model for the two oscillators is derived and verified numerically. Spice simulations using AMS BiCMOS 0.35 μ model parameters and experimental results are shown. Copyright © 2009 John Wiley & Sons, Ltd.

  20. Higher frequency of isolated PMS2 loss in colorectal tumors in Colombian population: preliminary results

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    Shamekh R

    2016-08-01

    Full Text Available Rania Shamekh,1 Mauro Cives,2 Jaime Mejia,3 Domenico Coppola,4 1Department of Pathology, University of South Florida, 2Department of Gastrointestinal Oncology, Moffitt Cancer Center, Tampa, FL, USA; 3Department of Pathology, Institutode Patologia Mejia Jimenez, Cali, Colombia; 4Department of Anatomic Pathology, Moffitt Cancer Center, Tampa, FL, USA Abstract: Colorectal cancer (CRC is the third most common cancer and the fourth most common cause of death worldwide. It accounts for >9% of all cancers. One of the pathogenic factors of CRC is germline mutation, leading to alteration and inactivation in the mismatch repair (MMR genes. The aim of the study is to compare the frequency of alterations in MMR protein expression in Caucasian CRC patients with Colombian CRC patients. A total of 45 Colombians and 48 Caucasians with CRC were studied. The microsatellite instability status of tumors was determined in primary CRC by immunohistochemistry using the automated Ventana Ultra. The combined loss of MLH1 and PMS2 was the most common alteration in both Colombian (11%, five out of 45 and Caucasian (12%, six out of 48 CRC patients. Interestingly, the loss of PMS2 expression in the presence of intact MLH1 was the second most common alteration in Colombians (8%, four out of 45, which was never seen in the Caucasian cohort (P=0.05. The loss of MLH1 alone and the combined loss of MSH6 and PMS2 expression were only observed in one out of 45 (2% Colombians but not in Caucasians. The combined loss of MSH2 and MSH6 was not observed in any of the patients studied. The preliminary findings support a significant difference in alterations of MMR protein expression in Colombian CRC patients compared with Caucasian CRC patients. These findings are novel and warrant further studies in larger cohorts. Keywords: colon cancer, MSI, MMR, immunohistochemistry

  1. A higher meal frequency may be associated with diminished weight loss after bariatric surgery

    Directory of Open Access Journals (Sweden)

    Angela Gadelha Ribeiro

    2009-11-01

    Full Text Available OBJECTIVE: This study aimed to investigate the relationship between meal frequency, the occurrence of vomiting and weight loss among patients submitted to Roux-en-Y gastric bypass up to 9 months after surgery. METHODS: Female patients (n = 80 were followed at 3-month intervals for 9 months. Weight, BMI, 24-hour dietary recall, drug consumption and vomiting episodes were recorded and compared with nutritional outcome. RESULTS: The BMI values at 3, 6 and 9 months were 45.1 ± 9.7, 39.9 ± 7.6 and 35.4 ± 8.2 kg/m², respectively. The corresponding choleric intakes were 535.6 ± 295.7, 677.1 ± 314.7 and 828.6 ± 398.2 kcal/day, and the numbers of daily meals were 5.0 ± 2.5, 4.7 ± 1.8 and 4.9 ± 1.0, respectively. The peak of vomiting episodes occurred within 6 months; however, patients tolerated this complication despite its high prevalence. A significant negative correlation between weight loss and diet fractioning, but not vomiting, was observed throughout the entire postoperative period (P = 0.001. CONCLUSIONS: 1 Frequent small meals were associated with a reduction in weight loss after gastric bypass and a decrease in vomiting episodes at 6 months, and 2 vomiting did not interfere with nutritional outcome. Unless required because of vomiting or other reasons, multiple small meals may not be advantageous after such intervention.

  2. Acupuncture plus Low-Frequency Electrical Stimulation (Acu-LFES Attenuates Diabetic Myopathy by Enhancing Muscle Regeneration.

    Directory of Open Access Journals (Sweden)

    Zhen Su

    Full Text Available Mortality and morbidity are increased in patients with muscle atrophy resulting from catabolic diseases such as diabetes. At present there is no pharmacological treatment that successfully reverses muscle wasting from catabolic conditions. We hypothesized that acupuncture plus low frequency electric stimulation (Acu-LFES would mimic the impact of exercise and prevent diabetes-induced muscle loss. Streptozotocin (STZ was used to induce diabetes in mice. The mice were then treated with Acu-LFES for 15 minutes daily for 14 days. Acupuncture points were selected according to the WHO Standard Acupuncture Nomenclature guide. The needles were connected to an SDZ-II electronic acupuncture device delivering pulses at 20Hz and 1mA. Acu-LFES prevented soleus and EDL muscle weight loss and increased hind-limb muscle grip function in diabetic mice. Muscle regeneration capacity was significantly increased by Acu-LFES. The expression of Pax7, MyoD, myogenin and embryo myosin heavy chain (eMyHC was significantly decreased in diabetic muscle vs. control muscle. The suppressed levels in diabetic muscle were reversed by Acu-LFES. The IGF-1 signaling pathway was also upregulated by Acu-LFES. Phosphorylation of Akt, mTOR and p70S6K were downregulated by diabetes leading to a decline in muscle mass, however, Acu-LFES countered the diabetes-induced decline. In addition, microRNA-1 and -206 were increased by Acu-LFES after 24 days of treatment. We conclude that Acu-LFES is effective in counteracting diabetes-induced skeletal muscle atrophy by increasing IGF-1 and its stimulation of muscle regeneration.

  3. Influence of percutaneous stimulation of hepatic region with mid-frequency pulse current on the activity of serum GSH-PX, SOD, T-AOC and the content of malondialdehyde in exercise-induced fatigued soldiers

    Directory of Open Access Journals (Sweden)

    Peng-yi DAI

    2014-03-01

    Full Text Available Objective  To explore the influence of percutaneous stimulation of the hepatic region with mid-frequency pulsed current on the serum activity of glutathione peroxidase (GSH-PX, superoxide dismutase (SOD and total antioxidant capacity and content of malondialdehyde (MDA in exercise-induced fatigued soldiers. Methods  Sixty healthy male recruits without training history were randomly divided into control group and stimulation group (n=30. Subjects in both groups received intensive training for 5 weeks (trained from Monday to Saturday, and rest on Sunday to establish an exercise-induced fatigue model. The recruits in stimulation group received rehabilitation therapy of percutaneous stimulation of the hepatic region with mid-frequency pulse current (frequency was 1024Hz, dynamic cycle 1s, stimulation time 20min, output intensity ≤80mA after the training immediately. In every Sunday morning of the 1st, 3rd and 5th week, venous blood samples were obtained from recruits of both groups for determination of the serum activity of GSH-PX, SOD and T-AOC and content of MDA. Results  In both groups, the serum activity of GSH-PX and T-AOC on 5th weekend was lower than that of 1st and 3rd weekends, and the serum activity of GSH-PX and T-AOC on 3rd weekend was lower than that of 1st weekend (P0.05; the serum MDA content on 5th weekend was higher than that of 3rd and 1st weekends, and the content on 3rd weekend was higher than that of 1st weekend (P<0.01. The activity of GSH-PX, SOD and T-AOC increased and the MDA content decreased on 1st, 3rd and 5th weekends in stimulation group when compared with control group (P<0.05, P<0.01. Conclusions  The percutaneous stimulation of the hepatic region by mid-frequency pulsed current in exercise-induced fatigued soldiers may improve the activity of antioxidant enzymes in the liver, enhance the function of antioxidant system, promote free radical scavenging, delay the occurrence of and promote the recovery from

  4. A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features

    Science.gov (United States)

    Zhou, Yu-Xuan; Wang, Hai-Peng; Bao, Xue-Liang; Lü, Xiao-Ying; Wang, Zhi-Gong

    2016-02-01

    Objective. Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. Approach. We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. Main Results. The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. Significance. Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle

  5. Modeling seismic stimulation: Enhanced non-aqueous fluid extraction from saturated porous media under pore-pressure pulsing at low frequencies

    Science.gov (United States)

    Lo, Wei-Cheng; Sposito, Garrison; Huang, Yu-Han

    2012-03-01

    Seismic stimulation, the application of low-frequency stress-pulsing to the boundary of a porous medium containing water and a non-aqueous fluid to enhance the removal of the latter, shows great promise for both contaminated groundwater remediation and enhanced oil recovery, but theory to elucidate the underlying mechanisms lag significantly behind the progress achieved in experimental research. We address this conceptual lacuna by formulating a boundary-value problem to describe pore-pressure pulsing at seismic frequencies that is based on the continuum theory of poroelasticity for an elastic porous medium permeated by two immiscible fluids. An exact analytical solution is presented that is applied numerically using elasticity parameters and hydraulic data relevant to recent proof-of-principle laboratory experiments investigating the stimulation-induced mobilization of trichloroethene (TCE) in water flowing through a compressed sand core. The numerical results indicated that significant stimulation-induced increases of the TCE concentration in effluent can be expected from pore-pressure pulsing in the frequency range of 25-100 Hz, which is in good agreement with what was observed in the laboratory experiments. Sensitivity analysis of our numerical results revealed that the TCE concentration in the effluent increases with the porous medium framework compressibility and the pulsing pressure. Increasing compressibility also leads to an optimal stimulation response at lower frequencies, whereas changing the pulsing pressure does not affect the optimal stimulation frequency. Within the context of our model, the dominant physical cause for enhancement of non-aqueous fluid mobility by seismic stimulation is the dilatory motion of the porous medium in which the solid and fluid phases undergo opposite displacements, resulting in stress-induced changes of the pore volume.

  6. Feasibility Studies on the Use of Higher Frequency Bands and Beamforming Selection Scheme for High Speed Train Communication

    Directory of Open Access Journals (Sweden)

    Ayotunde O. Laiyemo

    2017-01-01

    Full Text Available With increasing popularity of high speed trains and traffic forecast for future cellular networks, the need to provide improved data rates using higher frequency bands (HFBs for train passengers is becoming crucial. In this paper, we modify the OFDM frame structure for HST, taking into account the increasing sensitivity to speed at HFBs. A lower bound on the SNR/SINR for a given rate for reliable communication was derived considering the physical layer parameters from the OFDM frame. We also analyze different pathloss models in the context of examining the required gain needed to achieve the same performance as with microwave bands. Finally, we present a time-based analogue beamforming selection approach for HST. We observed that, irrespective of the pathloss models used, the required gains are within the same range. For the same SNR/SINR at different frequency bands, the achievable data rate varies with respect to the frequency bands. Our results show the potential of the use of HFBs. However, due to the increased sensitivity of some channel parameters, a maximum frequency band of 38 GHz is suggested. Evaluation of our proposed beamforming scheme indicates a close performance to the optimal SVD scheme with a marginal rate gap of less than 2 b/s/Hz.

  7. Welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems using fundamental- and higher-resonance frequencies.

    Science.gov (United States)

    Tsujino, Jiromaru; Hongoh, Misugi; Yoshikuni, Masafumi; Hashii, Hidekazu; Ueoka, Tetsugi

    2004-04-01

    The welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems that are driven at only the fundamental-resonance frequency vibration were compared, and also those of the welding systems that were driven at the fundamental and several higher resonance frequencies simultaneously were studied. At high frequency, welding characteristics can be improved due to the larger vibration loss of plastic materials. For welding of rather thin or small specimens, as the fundamental frequency of these welding systems is higher and the numbers of driven higher frequencies are driven simultaneously, larger welded area and weld strength were obtained.

  8. Radio frequency energy harvesting from a feeding source in a passive deep brain stimulation device for murine preclinical research.

    Science.gov (United States)

    Hosain, Md Kamal; Kouzani, Abbas Z; Tye, Susannah J; Samad, Mst Fateha; Kale, Rajas P; Bennet, Kevin E; Manciu, Felicia S; Berk, Michael

    2015-10-01

    This paper presents the development of an energy harvesting circuit for use with a head-mountable deep brain stimulation (DBS) device. It consists of a circular planar inverted-F antenna (PIFA) and a Schottky diode-based Cockcroft-Walton 4-voltage rectifier. The PIFA has the volume of π × 10(2) × 1.5 mm(3), resonance frequency of 915 MHz, and bandwidth of 16 MHz (909-925 MHz) at a return loss of -10 dB. The rectifier offers maximum efficiency of 78% for the input power of -5 dBm at a 5 kΩ load resistance. The developed rectenna operates efficiently at 915 MHz for the input power within -15 dBm to +5 dBm. For operating a DBS device, the DC voltage of 2 V is recorded from the rectenna terminal at a distance of 55 cm away from a 26.77 dBm transmitter in free space. An in-vitro test of the DBS device is presented. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  9. Low-Frequency Repetitive Transcranial Magnetic Stimulation and Intensive Occupational Therapy for Poststroke Patients with Upper Limb Hemiparesis: Preliminary Study of a 15-Day Protocol

    Science.gov (United States)

    Kakuda, Wataru; Abo, Masahiro; Kobayashi, Kazushige; Momosaki, Ryo; Yokoi, Aki; Fukuda, Akiko; Ishikawa, Atsushi; Ito, Hiroshi; Tominaga, Ayumi

    2010-01-01

    The purpose of the study was to determine the safety and feasibility of a 15-day protocol of low-frequency repetitive transcranial magnetic stimulation (rTMS) combined with intensive occupational therapy (OT) on motor function and spasticity in hemiparetic upper limbs in poststroke patients. Fifteen poststroke patients (age at study entry 55 [plus…

  10. Dysregulation of the descending pain system in temporomandibular disorders revealed by low-frequency sensory transcutaneous electrical nerve stimulation: a pupillometric study.

    Directory of Open Access Journals (Sweden)

    Annalisa Monaco

    Full Text Available Using computerized pupillometry, our previous research established that the autonomic nervous system (ANS is dysregulated in patients suffering from temporomandibular disorders (TMDs, suggesting a potential role for ANS dysfunction in pain modulation and the etiology of TMD. However, pain modulation hypotheses for TMD are still lacking. The periaqueductal gray (PAG is involved in the descending modulation of defensive behavior and pain through μ, κ, and δ opioid receptors. Transcutaneous electrical nerve stimulation (TENS has been extensively used for pain relief, as low-frequency stimulation can activate µ receptors. Our aim was to use pupillometry to evaluate the effect of low-frequency TENS stimulation of μ receptors on opioid descending pathways in TMD patients. In accordance with the Research Diagnostic Criteria for TMD, 18 females with myogenous TMD and 18 matched-controls were enrolled. All subjects underwent subsequent pupillometric evaluations under dark and light conditions before, soon after (end of stimulation and long after (recovery period sensorial TENS. The overall statistics derived from the darkness condition revealed no significant differences in pupil size between cases and controls; indeed, TENS stimulation significantly reduced pupil size in both groups. Controls, but not TMD patients, displayed significant differences in pupil size before compared with after TENS. Under light conditions, TMD patients presented a smaller pupil size compared with controls; the pupil size was reduced only in the controls. Pupil size differences were found before and during TENS and before and after TENS in the controls only. Pupillometry revealed that stimulating the descending opioid pathway with low-frequency sensory TENS of the fifth and seventh pairs of cranial nerves affects the peripheral target. The TMD patients exhibited a different pattern of response to TENS stimulation compared with the controls, suggesting that impaired

  11. [The application of high-frequency and iTBS transcranial magnetic stimulation for the treatment of spasticity in the patients presenting with secondary progressive multiple sclerosis].

    Science.gov (United States)

    Korzhova, J E; Chervyakov, A V; Poydasheva, A G; Kochergin, I A; Peresedova, A V; Zakharova, M N; Suponeva, N A; Chernikova, L A; Piradov, M A

    Spasticity is considered to be a common manifestation of multiple sclerosis. Muscle relaxants are not sufficiently effective; more than that, some of them often cause a variety of adverse reactions. Transcranial magnetic stimulation (TMS) can be a promising new tool for the treatment of spasticity. The objective of the present study was to compare the effectiveness of the two TMS protocols: rhythmic (high-frequency) TMS (rTMS) and stimulation with the theta bursts (iTBS) in terms of their ability to reduce spasticity in the patients presenting with multiple sclerosis. Twenty two patients with secondary-progressive multiple sclerosis were pseudo-randomized into two groups: those in the first (high-frequency) group received the treatment with the use of rTMS therapy at a frequency of 10 Hz; the patients of the second group, underwent stimulation with the theta bursts (iTBS). All the patients received 10 sessions of either stimulation applied to the primary motor area (M1) of both legs. The effectiveness of TMS protocols was evaluated before therapy and after 10 sessions of stimulation based on the Modified Ashworth scale (MAS), the expanded disability status scale (EDSS), and the Kurtzke functional scale (Kfs). In addition, the patients were interviewed before treatment, after 10 rTMS sessions, immediately after and within 2 and 12 weeks after the completion of the treatment using questionnaires for the evaluation of spasticity (SESS) , fatigue, and dysfunction of the pelvic organs (severity of defecation and urination disorders), fatigue. The study has demonstrated a significant reduction in spasticity in the patients of both groups at the end of the TMS protocol based on the MAS scale. There was no significant difference between the outcomes of the two protocols. Both had positive effect on the concomitant «non-motor» symptoms (fatigue, dysfunction of the pelvic organs). High-frequency transcranial magnetic stimulation (10 sessions of rTMS therapy at a frequency

  12. Effect of High-Frequency Transcranial Magnetic Stimulation on Craving in Substance Use Disorder: A Meta-Analysis.

    Science.gov (United States)

    Maiti, Rituparna; Mishra, Biswa Ranjan; Hota, Debasish

    2017-01-01

    Repetitive transcranial magnetic stimulation (rTMS), a noninvasive, neuromodulatory tool, has been used to reduce craving in different substance use disorders. There are some studies that have reported conflicting and inconclusive results; therefore, this meta-analysis was conducted to evaluate the effect of high-frequency rTMS on craving in substance use disorder and to investigate the reasons behind the inconsistency across the studies. The authors searched clinical trials from MEDLINE, Cochrane databases, and International Clinical Trials Registry Platform. The PRISMA guidelines, as well as recommended meta-analysis practices, were followed in the selection process, analysis, and reporting of the findings. The effect estimate used was the standardized mean difference (Hedge's g), and heterogeneity across the considered studies was explored using subgroup analyses. The quality assessment was done using the Cochrane risk of bias tool, and sensitivity analysis was performed to check the influences on effect size by statistical models. After screening and assessment of eligibility, finally 10 studies were included for meta-analysis, which includes six studies on alcohol and four studies on nicotine use disorder. The random-model analysis revealed a pooled effect size of 0.75 (95% CI=0.29 to 1.21, p=0.001), whereas the fixed-model analysis showed a large effect size of 0.87 (95% CI=0.63 to 1.12, peffect size of -0.06 (95% CI=-0.89 to 0.77, p=0.88). In the case of nicotine use disorder, random-model analysis revealed an effect size of 1.00 (95% CI=0.48 to 1.55, p=0.0001), whereas fixed-model analysis also showed a large effect size of 0.96 (95% CI=0.71 to 1.22). The present meta-analysis identified a beneficial effect of high-frequency rTMS on craving associated with nicotine use disorder but not alcohol use disorder.

  13. The repetition timing of high frequency afferent stimulation drives the bidirectional plasticity at central synapses in the rat medial vestibular nuclei.

    Science.gov (United States)

    Scarduzio, M; Panichi, R; Pettorossi, V E; Grassi, S

    2012-10-25

    In this study we show that high frequency stimulation (HFS, 100Hz) of afferent fibers to the medial vestibular nucleus (MVN) can induce opposite long-term modifications of synaptic responses in the type B neurons depending upon the stimulation pattern. Long burst stimulation (LBS: 2s) and short burst stimulation (SBS: 0.55s) were applied with different burst number (BN) and inter-burst intervals (IBI). It results that both LBS and SBS can induce either N-methyl-d aspartate receptors (NMDARs)-mediated long-term potentiation (LTP) or long-term depression (LTD), depending on temporal organization of repetitive bursts. In particular, the IBI plays a relevant role in guiding the shift from LTP to LTD since by using both LBS and SBS LTP is induced by shorter IBI than LTD. By contrast, the sign of long-term effect does not depend on the mean impulse frequency evaluated within the entire stimulation period. Therefore, the patterns of repetitive vestibular activation with different ratios between periods of increased activity and periods of basal activity may lead to LTP or LTD probably causing different levels of postsynaptic Ca(2+). On the whole, this study demonstrates that glutamatergic vestibular synapse in the MVN can undergo NMDAR-dependent bidirectional plasticity and puts forward a new aspect for understanding the adaptive and compensatory plasticity of the oculomotor responses. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

  14. Plants experiencing chronic internal exposure to ionizing radiation exhibit higher frequency of homologous recombination than acutely irradiated plants

    Energy Technology Data Exchange (ETDEWEB)

    Kovalchuk, O.; Kovalchuk, I.; Hohn, B. [Friedrich Miescher Institute, P.O. Box 2543, CH-4002 Basel (Switzerland); Arkhipov, A. [Chernobyl Scientific and Technical Center of International Research, Shkolnaya Str. 6, 255620 Chernobyl (Ukraine); Barylyak, I.; Karachov, I. [Ukrainian Scientific Genetics Center, Popudrenko Str. 50, 253660 Kiev (Ukraine); Titov, V. [Ivano-Frankivsk State Medical Academy, Galitska Str.2, 284000 Ivano-Frankivsk (Ukraine)

    2000-04-03

    different chemical composition, but equal radioactivity, exhibited different levels of HR, dependent upon the absorbed dose of radiation. Remarkably, we observed a much higher frequency of HR in plants exposed to chronic irradiation when compared to acutely irradiated plants. Although acute application of 0.1-0.5 Gy did not lead to an increase of frequency of HR, the chronic exposure of the plants to several orders of magnitude lower dose of 200 {mu}Gy led to a 5-6-fold induction of the frequency of HR as compared to the control.

  15. Efficacy of kilohertz-frequency and conventional spinal cord stimulation in rat models of different pain conditions.

    Science.gov (United States)

    Song, Zhiyang; Viisanen, Hanna; Meyerson, Björn A; Pertovaara, Antti; Linderoth, Bengt

    2014-04-01

    The aim was to compare the effects of high-frequency spinal cord stimulation (HF-SCS) at subparesthetic intensity with conventional SCS in rat models of different types of pain. In addition, microrecordings of afferent activity in the dorsal columns during both types of SCS were performed to elucidate their mode of action. Miniature SCS electrodes were implanted in all rats. One group was submitted to the spared nerve injury procedure (SNI) and another to inflammatory pain after carrageenan injection into a hind paw. All animals were tested for hypersensitivity to normally innocuous tactile and thermal stimuli. One group of normal healthy rats was submitted to acute nociceptive (pinch, heat) pain. Microrecording of afferent activity in the gracile nucleus (GN) was performed in a group of nerve-lesioned rats responding to conventional SCS. HF-SCS at 500, 1,000, or 10,000 Hz at subparesthetic amplitudes produced similar reductions in hypersensitivity due to nerve lesion as did conventional SCS at 50 Hz. HF-SCS showed no effect on thermal pain. A trial to rescue non-responders to conventional SCS using HF-SCS was not successful. There were no effects either of conventional or of HF-SCS on acute or inflammatory pain. Conventional SCS produced massive activation in the GN but no activation during HF-SCS, though normal peripherally evoked afferent activity remained. Conventional SCS proved equally effective to HF-SCS in various pain models. As no activity is conveyed rostrally in subparesthetic HF-SCS, we hypothesize that its mechanisms of action are primarily segmental. © 2014 International Neuromodulation Society.

  16. Active sources in the cutoff of centrifugal fans to reduce the blade tones at higher-order duct mode frequencies

    Science.gov (United States)

    Neise, W.; Koopmann, G. H.

    1991-01-01

    A previously developed (e.g., Neise and Koopmann, 1984; Koopmann et al., 1988) active noise control technique in which the unwanted acoustic signals from centrifugal fans are suppressed by placing two externally driven sources near the cutoff of the casing was applied to the frequency region where not only plane sound waves are propagational in the fan ducts but also higher-order acoustic modes. Using a specially designed fan noise testing facility, the performance of two fans (280-mm impeller diam and 508 mm diam) was monitored with static pressure taps mounted peripherally around the inlet nozzle. Experimental results show that the aerodynamically generated source pressure field around the cutoff is too complex to be successfully counterimaged by only two active sources introduced in this region. It is suggested that, for an efficient application of this noise control technique in the higher-order mode frequency regime, it is neccessary to use an active source involving larger number of individually driven loudspeakers.

  17. Low-frequency stimulation in anterior nucleus of thalamus alleviates kainate-induced chronic epilepsy and modulates the hippocampal EEG rhythm.

    Science.gov (United States)

    Wang, Yi; Liang, Jiao; Xu, Cenglin; Wang, Ying; Kuang, Yifang; Xu, Zhenghao; Guo, Yi; Wang, Shuang; Gao, Feng; Chen, Zhong

    2016-02-01

    High-frequency stimulation (HFS) of the anterior nucleus of thalamus (ANT) is a new and alternative option for the treatment of intractable epilepsy. However, the responder rate is relatively low. The present study was designed to determine the effect of low-frequency stimulation (LFS) in ANT on chronic spontaneous recurrent seizures and related pathological pattern in intra-hippocampal kainate mouse model. We found that LFS (1 Hz, 100 μs, 300 μA), but not HFS (100 Hz, 100 μs, 30 μA), in bilateral ANT significantly decreased the frequency of spontaneous recurrent seizures, either non-convulsive focal seizures or tonic-clonic generalized seizures. The anti-epileptic effect persisted for one week after LFS cessation, which manifested as a long-term inhibition of the frequency of seizures with short (20-60 s) and intermediate duration (60-120 s). Meanwhile, LFS decreased the frequency of high-frequency oscillations (HFOs) and interictal spikes, two indicators of seizure severity, whereas HFS increased the HFO frequency. Furthermore, LFS decreased the power of the delta band and increased the power of the gamma band of hippocampal background EEG. In addition, LFS, but not HFS, improved the performance of chronic epileptic mice in objection-location task, novel objection recognition and freezing test. These results provide the first evidence that LFS in ANT alleviates kainate-induced chronic epilepsy and cognitive impairment, which may be related to the modulation of the hippocampal EEG rhythm. This may be of great therapeutic significance for clinical treatment of epilepsy with deep brain stimulation. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Transcranial alternating current stimulation at beta frequency: lack of immediate effects on excitation and interhemispheric inhibition of the human motor cortex

    Directory of Open Access Journals (Sweden)

    Viola Rjosk

    2016-11-01

    Full Text Available Transcranial alternating current stimulation (tACS is a form of noninvasive brain stimulation and is capable of influencing brain oscillations and cortical networks. In humans, the endogenous oscillation frequency in sensorimotor areas peaks at 20 Hz. This beta-band typically occurs during maintenance of tonic motor output and seems to play a role in interhemispheric coordination of movements. Previous studies showed that tACS applied in specific frequency bands over primary motor cortex (M1 or the visual cortex modulates cortical excitability within the stimulated hemisphere. However, the particular impact remains controversial because effects of tACS were shown to be frequency, duration and location specific. Furthermore, the potential of tACS to modulate cortical interhemispheric processing, like interhemispheric inhibition (IHI, remains elusive. Transcranial magnetic stimulation (TMS is a noninvasive and well-tolerated method of directly activating neurons in superficial areas of the human brain and thereby a useful tool for evaluating the functional state of motor pathways. The aim of the present study was to elucidate the immediate effect of 10 min tACS in the β-frequency band (20 Hz over left M1 on IHI between M1s in 19 young, healthy, right-handed participants. A series of TMS measurements (MEP size, RMT, IHI from left to right M1 and vice versa was performed before and immediately after tACS or sham using a double-blinded, cross-over design. We did not find any significant tACS-induced modulations of intracortical excitation (as assessed by MEP size and RMT and/or interhemispheric inhibition (IHI. These results indicate that 10 min of 20 Hz tACS over left M1 seems incapable of modulating immediate brain activity or inhibition. Further studies are needed to elucidate potential aftereffects of 20 Hz tACS as well as frequency-specific effects of tACS on intracortical excitation and interhemispheric inhibition.

  19. How does higher frequency monitoring data affect the calibration of a process-based water quality model?

    Science.gov (United States)

    Jackson-Blake, Leah; Helliwell, Rachel

    2015-04-01

    Process-based catchment water quality models are increasingly used as tools to inform land management. However, for such models to be reliable they need to be well calibrated and shown to reproduce key catchment processes. Calibration can be challenging for process-based models, which tend to be complex and highly parameterised. Calibrating a large number of parameters generally requires a large amount of monitoring data, spanning all hydrochemical conditions. However, regulatory agencies and research organisations generally only sample at a fortnightly or monthly frequency, even in well-studied catchments, often missing peak flow events. The primary aim of this study was therefore to investigate how the quality and uncertainty of model simulations produced by a process-based, semi-distributed catchment model, INCA-P (the INtegrated CAtchment model of Phosphorus dynamics), were improved by calibration to higher frequency water chemistry data. Two model calibrations were carried out for a small rural Scottish catchment: one using 18 months of daily total dissolved phosphorus (TDP) concentration data, another using a fortnightly dataset derived from the daily data. To aid comparability, calibrations were carried out automatically using the Markov Chain Monte Carlo - DiffeRential Evolution Adaptive Metropolis (MCMC-DREAM) algorithm. Calibration to daily data resulted in improved simulation of peak TDP concentrations and improved model performance statistics. Parameter-related uncertainty in simulated TDP was large when fortnightly data was used for calibration, with a 95% credible interval of 26 μg/l. This uncertainty is comparable in size to the difference between Water Framework Directive (WFD) chemical status classes, and would therefore make it difficult to use this calibration to predict shifts in WFD status. The 95% credible interval reduced markedly with the higher frequency monitoring data, to 6 μg/l. The number of parameters that could be reliably auto

  20. An increase in alpha band frequency in resting state EEG after electrical stimulation of the ear in tinnitus patients - a pilot study

    Directory of Open Access Journals (Sweden)

    Marzena Mielczarek

    2016-10-01

    Full Text Available In our clinic invasive transtympanal promontory positive DC stimulations were first used, with a success rate of 42%. However, non-invasive hydrotransmissive negative DC stimulations are now favoured, with improvement being obtained in 37.8% directly after the treatment, and 51.3% in a follow up one month after treatment. The further improvement after one month may be due to neuroplastic changes at central level as a result of altered peripheral input. The aim of the study was to determine how a single electrical stimulation of the ear influences cortical activity, and whether changes observed in tinnitus after electrical stimulation are associated with any changes in cortical activity recorded in EEG.The study included 12 tinnitus patients(F–6, M-6 divided into two groups. Group I comprised six patients with unilateral tinnitus - unilateral, ipsilateral ES was performed. Group II comprised six patients with bilateral tinnitus - bilateral ES was performed.Electrical stimulation was performed using a custom-made apparatus.The active, silver probe – was immersed inside the external ear canal filled with saline. The passive electrode was placed on the forehead. The stimulating frequency was 250Hz, the intensity ranged from 0.14 to 1.08 mA. The voltage was kept constant at 3V. The duration of stimulation was four minutes. The EEG recording (Deymed QEST 32 was performed before and after electrical stimulation. We assessed the intensity of tinnitus on the visual analogue scale (1-10. Results.In both groups an improvement in VAS was observed– in group I - in five ears (83.3%, in group II - in seven ears (58.3%. In Group I,a significant increase in the upper and lower limits of the alpha frequency range was observed in the left central temporal and left frontal regions following electrical stimulation. These changes, however, were not correlated with improvement in tinnitus. No significant changes were observed in the beta and theta bands and in

  1. Prolonged high frequency electrical stimulation is lethal to motor axons of mice heterozygously deficient for the myelin protein P0 gene

    DEFF Research Database (Denmark)

    Alvarez, Susana; Moldovan, Mihai; Krarup, Christian

    2013-01-01

    demyelinating neuropathy reminiscent of CMT Type 1b. Accumulating evidence suggests that impulse conduction can become lethal to acutely demyelinated central and peripheral axons. Here we investigated the vulnerability of motor axons to long-lasting, high-frequency repetitive stimulation (RS) in P₀+/- mice...... as compared to WT littermates at 7, 12, and 20 months of age. RS was carried out in interrupted trains of 200 Hz trains for 3h. Tibial nerves were stimulated at the ankle while the evoked compound muscle action potentials (CMAPs) and the ascending compound nerve action potentials (CNAPs) were recorded from...... aging and the dysmyelinating disease process may contribute to the susceptibility to activity-induced axonal degeneration. It is possible that in aging mice and in P₀+/- there is inadequate energy-dependent Na(+)/K(+) pumping, as indicated by the reduced post-stimulation hyperpolarization, which may...

  2. Recent sediment dynamics in hadal trenches: Evidence for the influence of higher-frequency (tidal, near-inertial) fluid dynamics

    DEFF Research Database (Denmark)

    Turnewitsch, Robert; Falahat, Saeed; Stehlikova, Jirina

    2014-01-01

    finds evidence for another mechanism that is superimposed on, and counteracts, the focussing mechanism. This superimposed mechanism is related to higher-frequency (tidal, near-inertial) fluid dynamics. In particular, there is evidence for a strong and negative relation between the intensity...... but significant influence on particulate-matter dynamics and food supply in hadal trenches in particular, but possibly also in the deep seas in general. A mechanism for the influence of internal tides on sediment dynamics is proposed. (C) 2014 Elsevier Ltd. All rights reserved.......In addition to high hydrostatic pressure, scarcity of food is viewed as a factor that limits the abundance and activity of heterotrophic organisms at great ocean depths, including hadal trenches. Supply of nutritious food largely relies on the flux of organic-rich particulate matter from...

  3. ITER Plasma at Electron Cyclotron Frequency Domain: Stimulated Raman Scattering off Gould-Trivelpiece Modes and Generation of Suprathermal Electrons and Energetic Ions

    Science.gov (United States)

    Stefan, V. Alexander

    2011-04-01

    Stimulated Raman scattering in the electron cyclotron frequency range of the X-Mode and O-Mode driver with the ITER plasma leads to the ``tail heating'' via the generation of suprathermal electrons and energetic ions. The scattering off Trivelpiece-Gould (T-G) modes is studied for the gyrotron frequency of 170GHz; X-Mode and O-Mode power of 24 MW CW; on-axis B-field of 10T. The synergy between the two-plasmon decay and Raman scattering is analyzed in reference to the bulk plasma heating. Supported in part by Nikola TESLA Labs, La Jolla, CA

  4. Focus: Two-dimensional electron-electron double resonance and molecular motions: The challenge of higher frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Franck, John M.; Chandrasekaran, Siddarth; Dzikovski, Boris; Dunnam, Curt R.; Freed, Jack H., E-mail: jhf3@cornell.edu [Department of Chemistry and Chemical Biology and National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York 14853 (United States)

    2015-06-07

    The development, applications, and current challenges of the pulsed ESR technique of two-dimensional Electron-Electron Double Resonance (2D ELDOR) are described. This is a three-pulse technique akin to 2D Exchange Nuclear Magnetic Resonance, but involving electron spins, usually in the form of spin-probes or spin-labels. As a result, it required the extension to much higher frequencies, i.e., microwaves, and much faster time scales, with π/2 pulses in the 2-3 ns range. It has proven very useful for studying molecular dynamics in complex fluids, and spectral results can be explained by fitting theoretical models (also described) that provide a detailed analysis of the molecular dynamics and structure. We discuss concepts that also appear in other forms of 2D spectroscopy but emphasize the unique advantages and difficulties that are intrinsic to ESR. Advantages include the ability to tune the resonance frequency, in order to probe different motional ranges, while challenges include the high ratio of the detection dead time vs. the relaxation times. We review several important 2D ELDOR studies of molecular dynamics. (1) The results from a spin probe dissolved in a liquid crystal are followed throughout the isotropic → nematic → liquid-like smectic → solid-like smectic → crystalline phases as the temperature is reduced and are interpreted in terms of the slowly relaxing local structure model. Here, the labeled molecule is undergoing overall motion in the macroscopically aligned sample, as well as responding to local site fluctuations. (2) Several examples involving model phospholipid membranes are provided, including the dynamic structural characterization of the boundary lipid that coats a transmembrane peptide dimer. Additionally, subtle differences can be elicited for the phospholipid membrane phases: liquid disordered, liquid ordered, and gel, and the subtle effects upon the membrane, of antigen cross-linking of receptors on the surface of plasma membrane

  5. Focus: Two-dimensional electron-electron double resonance and molecular motions: The challenge of higher frequencies

    International Nuclear Information System (INIS)

    Franck, John M.; Chandrasekaran, Siddarth; Dzikovski, Boris; Dunnam, Curt R.; Freed, Jack H.

    2015-01-01

    The development, applications, and current challenges of the pulsed ESR technique of two-dimensional Electron-Electron Double Resonance (2D ELDOR) are described. This is a three-pulse technique akin to 2D Exchange Nuclear Magnetic Resonance, but involving electron spins, usually in the form of spin-probes or spin-labels. As a result, it required the extension to much higher frequencies, i.e., microwaves, and much faster time scales, with π/2 pulses in the 2-3 ns range. It has proven very useful for studying molecular dynamics in complex fluids, and spectral results can be explained by fitting theoretical models (also described) that provide a detailed analysis of the molecular dynamics and structure. We discuss concepts that also appear in other forms of 2D spectroscopy but emphasize the unique advantages and difficulties that are intrinsic to ESR. Advantages include the ability to tune the resonance frequency, in order to probe different motional ranges, while challenges include the high ratio of the detection dead time vs. the relaxation times. We review several important 2D ELDOR studies of molecular dynamics. (1) The results from a spin probe dissolved in a liquid crystal are followed throughout the isotropic → nematic → liquid-like smectic → solid-like smectic → crystalline phases as the temperature is reduced and are interpreted in terms of the slowly relaxing local structure model. Here, the labeled molecule is undergoing overall motion in the macroscopically aligned sample, as well as responding to local site fluctuations. (2) Several examples involving model phospholipid membranes are provided, including the dynamic structural characterization of the boundary lipid that coats a transmembrane peptide dimer. Additionally, subtle differences can be elicited for the phospholipid membrane phases: liquid disordered, liquid ordered, and gel, and the subtle effects upon the membrane, of antigen cross-linking of receptors on the surface of plasma membrane

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

    Directory of Open Access Journals (Sweden)

    Alm PA

    2013-06-01

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

  7. Effects of high-frequency stimulation of the internal pallidal segment on neuronal activity in the thalamus in parkinsonian monkeys

    OpenAIRE

    Kammermeier, Stefan; Pittard, Damien; Hamada, Ikuma; Wichmann, Thomas

    2016-01-01

    It is known that parkinsonism is associated with abnormalities in basal ganglia activity and that deep brain stimulation of these structures, a common treatment for Parkinson's disease, strongly alters basal ganglia output. However, parkinsonism- and stimulation-related activity changes in the ventral thalamus, a major recipient of basal ganglia output, remain controversial. These primate experiments demonstrate such changes, emphasizing emerging oscillatory activity patterns, and changes of ...

  8. Increased Eating Frequency Is Associated with Lower Obesity Risk, But Higher Energy Intake in Adults: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Yue-Qiao Wang

    2016-06-01

    Full Text Available Body weight is regulated by energy intake which occurs several times a day in humans. In this meta-analysis, we evaluated whether eating frequency (EF is associated with obesity risk and energy intake in adults without any dietary restriction. Experimental and observational studies published before July 2015 were selected through English-language literature searches in several databases. These studies reported the association between EF and obesity risk (odd ratios, ORs in adults who were not in dietary restriction. R software was used to perform statistical analyses. Ten cross-sectional studies, consisting of 65,742 participants, were included in this analysis. ORs were considered as effect size for the analysis about the effect of EF on obesity risk. Results showed that the increase of EF was associated with 0.83 time lower odds of obesity (i.e., OR = 0.83, 95% confidence intervals (CI 0.70–0.99, p = 0.040. Analysis about the effect of EF on differences in participants’ energy intake revealed that increased EF was associated with higher energy intake (β = 125.36, 95% CI 21.76–228.97, p = 0.017. We conclude that increased EF may lead to lower obesity risk but higher energy intake. Clinical trials are warranted to confirm these results and to assess the clinical practice applicability.

  9. Influence of extremely low frequency, low energy electromagnetic fields and combined mechanical stimulation on chondrocytes in 3-D constructs for cartilage tissue engineering.

    Science.gov (United States)

    Hilz, Florian M; Ahrens, Philipp; Grad, Sibylle; Stoddart, Martin J; Dahmani, Chiheb; Wilken, Frauke L; Sauerschnig, Martin; Niemeyer, Philipp; Zwingmann, Jörn; Burgkart, Rainer; von Eisenhart-Rothe, Rüdiger; Südkamp, Norbert P; Weyh, Thomas; Imhoff, Andreas B; Alini, Mauro; Salzmann, Gian M

    2014-02-01

    Articular cartilage, once damaged, has very low regenerative potential. Various experimental approaches have been conducted to enhance chondrogenesis and cartilage maturation. Among those, non-invasive electromagnetic fields have shown their beneficial influence for cartilage regeneration and are widely used for the treatment of non-unions, fractures, avascular necrosis and osteoarthritis. One very well accepted way to promote cartilage maturation is physical stimulation through bioreactors. The aim of this study was the investigation of combined mechanical and electromagnetic stress affecting cartilage cells in vitro. Primary articular chondrocytes from bovine fetlock joints were seeded into three-dimensional (3-D) polyurethane scaffolds and distributed into seven stimulated experimental groups. They either underwent mechanical or electromagnetic stimulation (sinusoidal electromagnetic field of 1 mT, 2 mT, or 3 mT; 60 Hz) or both within a joint-specific bioreactor and a coil system. The scaffold-cell constructs were analyzed for glycosaminoglycan (GAG) and DNA content, histology, and gene expression of collagen-1, collagen-2, aggrecan, cartilage oligomeric matrix protein (COMP), Sox9, proteoglycan-4 (PRG-4), and matrix metalloproteinases (MMP-3 and -13). There were statistically significant differences in GAG/DNA content between the stimulated versus the control group with highest levels in the combined stimulation group. Gene expression was significantly higher for combined stimulation groups versus static control for collagen 2/collagen 1 ratio and lower for MMP-13. Amongst other genes, a more chondrogenic phenotype was noticed in expression patterns for the stimulated groups. To conclude, there is an effect of electromagnetic and mechanical stimulation on chondrocytes seeded in a 3-D scaffold, resulting in improved extracellular matrix production. © 2013 Wiley Periodicals, Inc.

  10. Effect of low frequency electrical stimulation on seizure-induced short- and long-term impairments in learning and memory in rats.

    Science.gov (United States)

    Esmaeilpour, Khadijeh; Sheibani, Vahid; Shabani, Mohammad; Mirnajafi-Zadeh, Javad

    2017-01-01

    Kindled seizures can impair learning and memory. In the present study the effect of low-frequency electrical stimulation (LFS) on kindled seizure-induced impairment in spatial learning and memory was investigated and followed up to one month. Animals were kindled by electrical stimulation of hippocampal CA1 area in a semi-rapid manner (12 stimulations per day). One group of animals received four trials of LFS at 30s, 6h, 24h, and 30h following the last kindling stimulation. Each LFS trial was consisted of 4 packages at 5min intervals. Each package contained 200 monophasic square wave pulses of 0.1ms duration at 1Hz. The Open field, Morris water maze, and novel object recognition tests were done 48h, 1week, 2weeks, and one month after the last kindling stimulation respectively. Kindled animals showed a significant impairment in learning and memory compared to control rats. LFS decreased the kindling-induced learning and memory impairments at 24h and one week following its application, but not at 2week or 1month after kindling. In the group of animals that received the same 4 trials of LFS again one week following the last kindling stimulation, the improving effect of LFS was observed even after one month. Obtained results showed that application of LFS in fully kindled animals has a long-term improving effect on spatial learning and memory. This effect can remain for a long duration (one month in this study) by increasing the number of applied LFS. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Clinical and electrophysiological impact of repetitive low-frequency transcranial magnetic stimulation on the sensory–motor network in patients with restless legs syndrome

    Science.gov (United States)

    Cantone, Mariagiovanna; Aricò, Debora; Lanuzza, Bartolo; Cosentino, Filomena Irene Ilaria; Paci, Domenico; Papotto, Maurizio; Pennisi, Manuela; Bella, Rita; Pennisi, Giovanni; Paulus, Walter; Ferri, Raffaele

    2018-01-01

    Background: Based on the hyperexcitability and disinhibition observed in patients with restless legs syndrome (RLS) following transcranial magnetic stimulation (TMS), we conducted a study with low-frequency repetitive TMS (rTMS) over the primary motor (M1) and somatosensory cortical areas (S1) in patients with RLS. Methods: A total of 13 right-handed patients and 10 age-matched controls were studied using clinical scales and TMS. Measurements included resting motor threshold (rMT), motor-evoked potentials (MEPs), cortical silent period (CSP), and central motor conduction time (CMCT). A single evening session of rTMS (1 Hz, 20 trains, 50 stimuli each) was administered over the left M1, left S1, and sham stimulation over M1 in a random order. Clinical and TMS measures were repeated after each stimulation modality. Results: Baseline CSP was shorter in patients than in controls and remained shorter in patients for both motor and somatosensory stimulation. The patients reported a subjective improvement of both initiating and maintaining sleep the night after the rTMS over S1. Patients exhibited a decrease in rMT after rTMS of S1 only, although the effect was smaller than in controls. MEP latency and CMCT changed only in controls after stimulation. Sham stimulation was without effect on the observed variables. Conclusions: rTMS on S1-M1 connectivity alleviated the sensory–motor complaints of RLS patients. The TMS indexes of excitation and inhibition indicate an intracortical and corticospinal imbalance, mainly involving gamma-aminobutyric acid (GABA)ergic and glutamatergic circuitries, as well as an impairment of the short-term mechanisms of cortical plasticity. The rTMS-induced activation of the dorsal striatum with the consequent increase of dopamine release may have contributed to the clinical and neurophysiological outcome. PMID:29511386

  12. Clinical and electrophysiological impact of repetitive low-frequency transcranial magnetic stimulation on the sensory-motor network in patients with restless legs syndrome.

    Science.gov (United States)

    Lanza, Giuseppe; Cantone, Mariagiovanna; Aricò, Debora; Lanuzza, Bartolo; Cosentino, Filomena Irene Ilaria; Paci, Domenico; Papotto, Maurizio; Pennisi, Manuela; Bella, Rita; Pennisi, Giovanni; Paulus, Walter; Ferri, Raffaele

    2018-01-01

    Based on the hyperexcitability and disinhibition observed in patients with restless legs syndrome (RLS) following transcranial magnetic stimulation (TMS), we conducted a study with low-frequency repetitive TMS (rTMS) over the primary motor (M1) and somatosensory cortical areas (S1) in patients with RLS. A total of 13 right-handed patients and 10 age-matched controls were studied using clinical scales and TMS. Measurements included resting motor threshold (rMT), motor-evoked potentials (MEPs), cortical silent period (CSP), and central motor conduction time (CMCT). A single evening session of rTMS (1 Hz, 20 trains, 50 stimuli each) was administered over the left M1, left S1, and sham stimulation over M1 in a random order. Clinical and TMS measures were repeated after each stimulation modality. Baseline CSP was shorter in patients than in controls and remained shorter in patients for both motor and somatosensory stimulation. The patients reported a subjective improvement of both initiating and maintaining sleep the night after the rTMS over S1. Patients exhibited a decrease in rMT after rTMS of S1 only, although the effect was smaller than in controls. MEP latency and CMCT changed only in controls after stimulation. Sham stimulation was without effect on the observed variables. rTMS on S1-M1 connectivity alleviated the sensory-motor complaints of RLS patients. The TMS indexes of excitation and inhibition indicate an intracortical and corticospinal imbalance, mainly involving gamma-aminobutyric acid (GABA)ergic and glutamatergic circuitries, as well as an impairment of the short-term mechanisms of cortical plasticity. The rTMS-induced activation of the dorsal striatum with the consequent increase of dopamine release may have contributed to the clinical and neurophysiological outcome.

  13. The influence of low-frequency left prefrontal repetitive transcranial magnetic stimulation on memory for words but not for faces

    Czech Academy of Sciences Publication Activity Database

    Škrdlantová, L.; Horáček, J.; Dockery, C.; Lukavský, Jiří; Kopeček, M.; Preiss, M.; Novák, T.; Höschl, C.

    2005-01-01

    Roč. 54, č. 1 (2005), s. 123-128 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z70250504 Keywords : face memory * verbal memory * repetitive transcranial magnetic stimulation Subject RIV: AN - Psychology Impact factor: 1.806, year: 2005 http://www.biomed.cas.cz/physiolres/pdf/54/54_123.pdf

  14. Low-frequency brain stimulation to the left dorsolateral prefrontal cortex increases the negative impact of social exclusion among those high in personal distress.

    Science.gov (United States)

    Fitzgibbon, Bernadette Mary; Kirkovski, Melissa; Bailey, Neil Wayne; Thomson, Richard Hilton; Eisenberger, Naomi; Enticott, Peter Gregory; Fitzgerald, Paul Bernard

    2017-06-01

    The dorsolateral prefrontal cortex (DLPFC) is thought to play a key role in the cognitive control of emotion and has therefore, unsurprisingly, been implicated in the regulation of physical pain perception. This brain region may also influence the experience of social pain, which has been shown to activate similar neural networks as seen in response to physical pain. Here, we applied sham or active low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC, previously shown to exert bilateral effects in pain perception, in healthy participants. Following stimulation, participants played the "Cyberball Task"; an online ball-tossing game in which the subject participant is included or excluded. Compared to sham, rTMS did not modulate behavioural response to social exclusion. However, within the active rTMS group only, greater trait personal distress was related to enhanced negative outcomes to social exclusion. These results add further support to the notion that the effect of brain stimulation is not homogenous across individuals, and indicates the need to consider baseline individual differences when assessing response to brain stimulation. This seems particularly relevant in social neuroscience investigations, where trait factors may have a meaningful effect.

  15. Effects of high-frequency stimulation of the internal pallidal segment on neuronal activity in the thalamus in parkinsonian monkeys

    Science.gov (United States)

    Kammermeier, Stefan; Pittard, Damien; Hamada, Ikuma

    2016-01-01

    Deep brain stimulation of the internal globus pallidus (GPi) is a major treatment for advanced Parkinson's disease. The effects of this intervention on electrical activity patterns in targets of GPi output, specifically in the thalamus, are poorly understood. The experiments described here examined these effects using electrophysiological recordings in two Rhesus monkeys rendered moderately parkinsonian through treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), after sampling control data in the same animals. Analysis of spontaneous spiking activity of neurons in the basal ganglia-receiving areas of the ventral thalamus showed that MPTP-induced parkinsonism is associated with a reduction of firing rates of segments of the data that contained neither bursts nor decelerations, and with increased burst firing. Spectral analyses revealed an increase of power in the 3- to 13-Hz band and a reduction in the γ-range in the spiking activity of these neurons. Electrical stimulation of the ventrolateral motor territory of GPi with macroelectrodes, mimicking deep brain stimulation in parkinsonian patients (bipolar electrodes, 0.5 mm intercontact distance, biphasic stimuli, 120 Hz, 100 μs/phase, 200 μA), had antiparkinsonian effects. The stimulation markedly reduced oscillations in thalamic firing in the 13- to 30-Hz range and uncoupled the spiking activity of recorded neurons from simultaneously recorded local field potential (LFP) activity. These results confirm that oscillatory and nonoscillatory characteristics of spontaneous activity in the basal ganglia receiving ventral thalamus are altered in MPTP-induced parkinsonism. Electrical stimulation of GPi did not entrain thalamic activity but changed oscillatory activity in the ventral thalamus and altered the relationship between spikes and simultaneously recorded LFPs. PMID:27683881

  16. Basic and Meal Stimulated Plasma GIP Levels are Higher in Lean PCOS Women with FAI over 5.

    Science.gov (United States)

    Milewicz, T; Migacz, K; Kiałka, M; Rogatko, I; Kowalczuk, A; Spalkowska, M; Mrozińska, S; Czajkowska, Z; Sztefko, K

    2016-02-01

    Glucose dependent insulinotropic peptide (GIP) belongs to the incretins which are responsible for 70% of the insulin release after oral glucose intake. Its impaired secretion was noted in several conditions involving insulin resistance, including polycystic ovary syndrome (PCOS), known as the state with increased testosterone level. This paper considers a possible relationship between the free androgen index (FAI) and basal as well as meal stimulated level of GIP in lean women affected by PCOS. To our knowledge, no previous study has evaluated the matter so far. cross-sectional study 50 age-matched lean women (BMI=20.76±1.83) were enrolled to the study and divided into 2 groups. Patients with phenotype with FAIPCOS patients with FAI>5 formed group 2. All subjects underwent standard meal test. Serum GIP concentration was determined both at fasting and at 60 min of the test. Calculations were carried out using Statistica 10. Mann-Whitney test indicated a statistically significant difference in medians values of GIP plasma levels between groups on fasting (36.4 pg/ml vs. 59.6 pg/ml; p=0.0007) and at 60 min after meal test (50.1 pg/ml vs. 72.5 pg/ml; p=0.006). Spearman test indicated significant positive correlation between FAI and GIP levels at 0' and 60' in total study population (0':R=0.37;p=0.008; 60':R=0.28; p=0.049). Excess androgen activity might be a factor contributing to alter secretion of incretins in lean PCOS women. However it could not be ruled out that it is also possible that increased GIP levels might induce hyperandrogenemia in PCOS. An increased GIP levels may induce hyperinsulinemia and play an additive to insulin resistance role in progression to diabetes mellitus type 2 (DMT2). © Georg Thieme Verlag KG Stuttgart · New York.

  17. Subpopulations of lymphocytes and their bearing on the radiation dose-response of the human lymphocyte (cell survival, mitogenic stimulation and chromosome aberration frequency)

    International Nuclear Information System (INIS)

    Schwartz, J.L.

    1979-01-01

    To determine whether in the lymphocyte the frequency of chromosome aberrations might be influenced by a differential radiation response of the varying types of cells, as well as interactions among them, subpopulations were separated on the basis of differences in cell surface receptors. The subpopulations, namely, T and B lymphocytes and three T subsets, T-M, T-G, T-null, were found to differ in radiosensitivity as measured by survival in culture and mitotic index after PHA stimulation. All the populations studied are represented to varying degrees among the mitotic cells of unirradiated samples 48 hours after PHA stimulation. At increasing doses of 6 Co gamma rays (50, 100, 250, 500 rads), however, their proportions change both as a direct result of irradiation, such as cell killing, and as an indirect effect, such as the reduction in suppressor cell action

  18. High-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS Improves Functional Recovery by Enhancing Neurogenesis and Activating BDNF/TrkB Signaling in Ischemic Rats

    Directory of Open Access Journals (Sweden)

    Jing Luo

    2017-02-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS has rapidly become an attractive therapeutic approach for stroke. However, the mechanisms underlying this remain elusive. This study aimed to investigate whether high-frequency rTMS improves functional recovery mediated by enhanced neurogenesis and activation of brain-derived neurotrophic factor (BDNF/tropomyosin-related kinase B (TrkB pathway and to compare the effect of conventional 20 Hz rTMS and intermittent theta burst stimulation (iTBS on ischemic rats. Rats after rTMS were sacrificed seven and 14 days after middle cerebral artery occlusion (MCAO, following evaluation of neurological function. Neurogenesis was measured using specific markers: Ki67, Nestin, doublecortin (DCX, NeuN and glial fibrillary acidic protein (GFAP, and the expression levels of BDNF were visualized by Western blotting and RT-PCR analysis. Both high-frequency rTMS methods significantly improved neurological function and reduced infarct volume. Moreover, 20 Hz rTMS and iTBS significantly promoted neurogenesis, shown by an increase of Ki67/DCX, Ki67/Nestin, and Ki67/NeuN-positive cells in the peri-infarct striatum. These beneficial effects were accompanied by elevated protein levels of BDNF and phosphorylated-TrkB. In conclusion, high-frequency rTMS improves functional recovery possibly by enhancing neurogenesis and activating BDNF/TrkB signaling pathway and conventional 20 Hz rTMS is better than iTBS at enhancing neurogenesis in ischemic rats.

  19. Frequency and structure of stimulant designer drug consumption among suspected drug users in Budapest and South-East Hungary in 2012-2013.

    Science.gov (United States)

    Institóris, László; Árok, Zsófia; Seprenyi, Katalin; Varga, Tibor; Sára-Klausz, Gabriella; Keller, Éva; Tóth, Réka A; Sala, Leonardo; Kereszty, Éva; Róna, Kálmán

    2015-03-01

    Identification of abuse and frequency patterns of stimulant designer drugs (SDDs) provides important information for their risk assessment and legislative control. In the present study urine and/or blood samples of suspected drug users in criminal cases were analysed by GC-MS for 38 SDDs, and for the most frequent illicit and psychoactive licit drugs in Hungary. Between July 2012 and June 2013, 2744 suspected drug users were sampled in Budapest and during 2012 and 2013, 774 persons were sampled in South-East Hungary (Csongrád County - neighbour the Romanian and Serbian borders). In Budapest 71.4% of cases, and in South-East Hungary 61% of cases were positive for at least one substance. Pentedrone was the most frequent SDD in both regions; however, the frequency distribution of the remaining drugs was highly diverse. SDDs were frequently present in combination with other drugs - generally with amphetamine or other stimulants, cannabis and/or benzodiazepines. The quarterly distribution of positive samples indicated remarkable seasonal changes in the frequency and pattern of consumption. Substances placed on the list of illicit drugs (mephedrone, 4-fluoro-amphetamine, MDPV, methylone, 4-MEC) showed a subsequent drop in frequency and were replaced by other SDDs (pentedrone, 3-MMC, methiopropamine, etc.). Newly identified compounds from seized materials were added to the list of new psychoactive substances ("Schedule C"). While the risk assessment of substances listed in Schedule C has to be performed within 2 years after scheduling, continuous monitoring of their presence and frequency among drug users is essential. In summary, our results suggest which substances should be dropped from the list of SDDs measured in biological samples; while the appearance of new substances from seized materials indicate the need for developing adequate standard analytical methods. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Consumption Frequency of Foods Away from Home Linked with Higher Body Mass Index and Lower Fruit and Vegetable Intake among Adults: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Rebecca A. Seguin

    2016-01-01

    Full Text Available Introduction. Consumption of foods prepared away from home (FAFH has grown steadily since the 1970s. We examined the relationship between FAFH and body mass index (BMI and fruit and vegetable (FV consumption. Methods. Frequency of FAFH, daily FV intake, height and weight, and sociodemographic data were collected using a telephone survey in 2008-2009. Participants included a representative sample of 2,001 adult men and women (mean age 54±15 years residing in King County, WA, with an analytical sample of 1,570. Frequency of FAFH was categorized as 0-1, 2–4, or 5+ times per week. BMI was calculated from self-reported height and weight. We examined the relationship between FAFH with FV consumption and BMI using multivariate models. Results. Higher frequency of FAFH was associated with higher BMI, after adjusting for age, income, education, race, smoking, marital status, and physical activity (women: p=0.001; men: p=0.003. There was a negative association between frequency of FAFH and FV consumption. FAFH frequency was significantly (p<0.001 higher among males than females (43.1% versus 54.0% eating out 0-1 meal per week, resp.. Females reported eating significantly (p<0.001 more FV than males. Conclusion. Among adults, higher frequency of FAFH was related to higher BMI and less FV consumption.

  1. Consumption Frequency of Foods Away from Home Linked with Higher Body Mass Index and Lower Fruit and Vegetable Intake among Adults: A Cross-Sectional Study

    Science.gov (United States)

    Seguin, Rebecca A.; Aggarwal, Anju; Vermeylen, Francoise; Drewnowski, Adam

    2016-01-01

    Introduction. Consumption of foods prepared away from home (FAFH) has grown steadily since the 1970s. We examined the relationship between FAFH and body mass index (BMI) and fruit and vegetable (FV) consumption. Methods. Frequency of FAFH, daily FV intake, height and weight, and sociodemographic data were collected using a telephone survey in 2008-2009. Participants included a representative sample of 2,001 adult men and women (mean age 54 ± 15 years) residing in King County, WA, with an analytical sample of 1,570. Frequency of FAFH was categorized as 0-1, 2–4, or 5+ times per week. BMI was calculated from self-reported height and weight. We examined the relationship between FAFH with FV consumption and BMI using multivariate models. Results. Higher frequency of FAFH was associated with higher BMI, after adjusting for age, income, education, race, smoking, marital status, and physical activity (women: p = 0.001; men: p = 0.003). There was a negative association between frequency of FAFH and FV consumption. FAFH frequency was significantly (p < 0.001) higher among males than females (43.1% versus 54.0% eating out 0-1 meal per week, resp.). Females reported eating significantly (p < 0.001) more FV than males. Conclusion. Among adults, higher frequency of FAFH was related to higher BMI and less FV consumption. PMID:26925111

  2. Low-Magnitude, High-Frequency Vibration Fails to Accelerate Ligament Healing but Stimulates Collagen Synthesis in the Achilles Tendon.

    Science.gov (United States)

    Thompson, William R; Keller, Benjamin V; Davis, Matthew L; Dahners, Laurence E; Weinhold, Paul S

    2015-05-01

    Low-magnitude, high-frequency vibration accelerates fracture and wound healing and prevents disuse atrophy in musculoskeletal tissues. To investigate the role of low-magnitude, high-frequency vibration as a treatment to accelerate healing of an acute ligament injury and to examine gene expression in the intact Achilles tendon of the injured limb after low-magnitude, high-frequency vibration. Controlled laboratory study. Complete surgical transection of the medial collateral ligament (MCL) was performed in 32 Sprague-Dawley rats, divided into control and low-magnitude, high-frequency vibration groups. Low-magnitude, high-frequency vibration started on postoperative day 2, and rats received vibration for 30 minutes a day for 12 days. All rats were sacrificed 2 weeks after the operation, and their intact and injured MCLs were biomechanically tested or used for histological analysis. Intact Achilles tendons from the injured limb were evaluated for differences in gene expression. Mechanical testing revealed no differences in the ultimate tensile load or the structural stiffness between the control and vibration groups for either the injured or intact MCL. Vibration exposure increased gene expression of collagen 1 alpha (3-fold), interleukin 6 (7-fold), cyclooxygenase 2 (5-fold), and bone morphogenetic protein 12 (4-fold) in the intact Achilles tendon when compared with control tendons ( P frequency vibration treatment, significant enhancements in gene expression were observed in the intact Achilles tendon. These included collagen, several inflammatory cytokines, and growth factors critical for tendons. As low-magnitude, high-frequency vibration had no negative effects on ligament healing, vibration therapy may be a useful tool to accelerate healing of other tissues (bone) in multitrauma injuries without inhibiting ligament healing. Additionally, the enhanced gene expression in response to low-magnitude, high-frequency vibration in the intact Achilles tendon suggests the

  3. Cervical vagus nerve stimulation augments spontaneous discharge in second- and higher-order sensory neurons in the rat nucleus of the solitary tract.

    Science.gov (United States)

    Beaumont, Eric; Campbell, Regenia P; Andresen, Michael C; Scofield, Stephanie; Singh, Krishna; Libbus, Imad; KenKnight, Bruce H; Snyder, Logan; Cantrell, Nathan

    2017-08-01

    Vagus nerve stimulation (VNS) currently treats patients with drug-resistant epilepsy, depression, and heart failure. The mild intensities used in chronic VNS suggest that primary visceral afferents and central nervous system activation are involved. Here, we measured the activity of neurons in the nucleus of the solitary tract (NTS) in anesthetized rats using clinically styled VNS. Our chief findings indicate that VNS at threshold bradycardic intensity activated NTS neuron discharge in one-third of NTS neurons. This VNS directly activated only myelinated vagal afferents projecting to second-order NTS neurons. Most VNS-induced activity in NTS, however, was unsynchronized to vagal stimuli. Thus, VNS activated unsynchronized activity in NTS neurons that were second order to vagal afferent C-fibers as well as higher-order NTS neurons only polysynaptically activated by the vagus. Overall, cardiovascular-sensitive and -insensitive NTS neurons were similarly activated by VNS: 3/4 neurons with monosynaptic vagal A-fiber afferents, 6/42 neurons with monosynaptic vagal C-fiber afferents, and 16/21 polysynaptic NTS neurons. Provocatively, vagal A-fibers indirectly activated C-fiber neurons during VNS. Elevated spontaneous spiking was quantitatively much higher than synchronized activity and extended well into the periods of nonstimulation. Surprisingly, many polysynaptic NTS neurons responded to half the bradycardic intensity used in clinical studies, indicating that a subset of myelinated vagal afferents is sufficient to evoke VNS indirect activation. Our study uncovered a myelinated vagal afferent drive that indirectly activates NTS neurons and thus central pathways beyond NTS and support reconsideration of brain contributions of vagal afferents underpinning of therapeutic impacts. NEW & NOTEWORTHY Acute vagus nerve stimulation elevated activity in neurons located in the medial nucleus of the solitary tract. Such stimuli directly activated only myelinated vagal afferents

  4. Higher frequency of brain abnormalities in neuromyelitis optica spectrum disorder patients without primary Sjögren's syndrome.

    Science.gov (United States)

    Gu, Li-Na; Zhang, Min; Zhu, Hui; Liu, Jing-Yao

    2016-10-01

    Neuromyelitis optica spectrum disorder often co-exists with primary Sjögren's syndrome. We compared the clinical features of 16 neuromyelitis optica spectrum disorder patients with ( n = 6) or without primary Sjögren's syndrome ( n = 10). All patients underwent extensive clinical, laboratory, and MRI evaluations. There were no statistical differences in demographics or first neurological involvement at onset between neuromyelitis optica spectrum disorder patients with and without primary Sjögren's syndrome. The laboratory findings of cerebrospinal fluid oligoclonal banding, serum C-reactive protein, antinuclear autoantibody, anti-Sjögren's-syndrome-related antigen A antibodies, anti-Sjögren's-syndrome-related antigen B antibodies, and anti-Sm antibodies were significantly higher in patients with primary Sjögren's syndrome than those without. Anti-aquaporin 4 antibodies were detectable in 67% (4/6) of patients with primary Sjögren's syndrome and in 60% (6/10) of patients without primary Sjögren's syndrome. More brain abnormalities were observed in patients without primary Sjögren's syndrome than in those with primary Sjögren's syndrome. Segments lesions (> 3 centrum) were noted in 50% (5/10) of patients without primary Sjögren's syndrome and in 67% (4/6) of patients with primary Sjögren's syndrome. These findings indicate that the clinical characteristics of neuromyelitis optica spectrum disorder patients with and without primary Sjögren's syndrome are similar. However, neuromyelitis optica spectrum disorder patients without primary Sjögren's syndrome have a high frequency of brain abnormalities.

  5. Recent sediment dynamics in hadal trenches: Evidence for the influence of higher-frequency (tidal, near-inertial) fluid dynamics

    Science.gov (United States)

    Turnewitsch, Robert; Falahat, Saeed; Stehlikova, Jirina; Oguri, Kazumasa; Glud, Ronnie N.; Middelboe, Mathias; Kitazato, Hiroshi; Wenzhöfer, Frank; Ando, Kojiro; Fujio, Shinzou; Yanagimoto, Daigo

    2014-08-01

    In addition to high hydrostatic pressure, scarcity of food is viewed as a factor that limits the abundance and activity of heterotrophic organisms at great ocean depths, including hadal trenches. Supply of nutritious food largely relies on the flux of organic-rich particulate matter from the surface ocean. It has been speculated that the shape of hadal trenches helps to ‘funnel' particulate matter into the deeper parts of the trench, leading to sediment ‘focussing' and improved benthic food supply. Here we investigate for five Northwest Pacific trenches the efficiency of sediment focussing by evaluating ratios of measured (sediment-derived) and expected (water-column-derived) sedimentary inventories of the naturally occurring and radioactive particulate-matter tracer 210Pbxs. The sites comprise a broad range of surface-ocean productivity and physical-oceanographic regimes. Across the five trench-axis settings the inventory ratio varies between 0.5 and 4.1, with four trench-axis settings having ratios>1 (sediment focussing) and one trench-axis setting a ratiowinnowing). Although the fluid- and sediment-dynamical forcing behind sediment focussing remains unclear, this study finds evidence for another mechanism that is superimposed on, and counteracts, the focussing mechanism. This superimposed mechanism is related to higher-frequency (tidal, near-inertial) fluid dynamics. In particular, there is evidence for a strong and negative relation between the intensity of propagating internal tides and the extent of sediment focussing in the trench-axis. The relation can be approximated by a power function and the most intense drop in sediment focussing already occurs at moderate internal-tide intensities. This suggests that propagating internal tides may have a subtle but significant influence on particulate-matter dynamics and food supply in hadal trenches in particular, but possibly also in the deep seas in general. A mechanism for the influence of internal tides on

  6. Enhanced brain responses to C-fiber input in the area of secondary hyperalgesia induced by high-frequency electrical stimulation of the skin.

    Science.gov (United States)

    van den Broeke, Emanuel N; Mouraux, André

    2014-11-01

    High-frequency electrical stimulation (HFS) of the human skin induces an increase in both mechanical and heat pain sensitivity in the surrounding unconditioned skin. The aim of this study was to investigate the effect of HFS on the intensity of perception and brain responses elicited by the selective activation of C fibers. HFS was applied to the ventral forearm of 15 healthy volunteers. Temperature-controlled CO2 laser stimulation was used to activate selectively low-threshold C-fiber afferents without concomitantly activating Aδ-fiber afferents. These stimuli were detected with reaction times compatible with the conduction velocity of C fibers. The intensity of perception and event-related brain potentials (ERPs) elicited by thermal stimuli delivered to the surrounding unconditioned skin were recorded before (T0) and after HFS (T1: 20 min after HFS; T2: 45 min after HFS). The contralateral forearm served as a control. Mechanical hyperalgesia following HFS was confirmed by measuring the change in the intensity of perception elicited by mechanical punctate stimuli. HFS resulted in increased intensity of perception to mechanical punctate stimulation and selective C-fiber thermal stimulation at both time points. In contrast, the N2 wave of the ERP elicited by C-fiber stimulation (679 ± 88 ms; means ± SD) was enhanced at T1 but not at T2. The P2 wave (808 ± 105 ms) was unaffected by HFS. Our results suggest that HFS enhances the sensitivity to thermal C-fiber input in the area of secondary hyperalgesia. However, there was no significant enhancement of the magnitude of the C-fiber ERPs at T2, suggesting that quickly adapting C fibers do not contribute to this enhancement. Copyright © 2014 the American Physiological Society.

  7. A common polymorphic allele of the LH beta-subunit gene is associated with higher exogenous FSH consumption during controlled ovarian stimulation for assisted reproductive technology

    DEFF Research Database (Denmark)

    Alviggi, Carlo; Pettersson, Kim; Longobardi, Salvatore

    2013-01-01

    BACKGROUND: V-betaLH is a common genetic variant of LH caused by two polymorphic base changes in the beta subunit gene, altering the amino acid sequence (Trp8Arg and Ile15Thr). In a previous-preliminary trial performed in women undergoing IVF, it was demonstrated that carriers of v-betaLH show sub......-optimal ovarian response to a standard long GnRH-agonist down -regulation protocol when stimulated with pure recombinant FSH (r-hFSH). The aim of this study was to confirm the hypothesis that women with v-betaLH display hypo-sensitivity to exogenous FSH in a larger IVF population and to explore the frequency...... of this variant in a Danish female population. METHODS: In the present study, the effect of v-betaLH was retrospectively investigated in a larger series of women undergoing controlled ovarian stimulation (COS) and, for the first time, in a Danish IVF population. A total of 220 normogonadotrophic women following...

  8. Higher Thyroid-Stimulating Hormone, Triiodothyronine and Thyroxine Values Are Associated with Better Outcome in Acute Liver Failure.

    Science.gov (United States)

    Anastasiou, Olympia; Sydor, Svenja; Sowa, Jan-Peter; Manka, Paul; Katsounas, Antonios; Syn, Wing-Kin; Führer, Dagmar; Gieseler, Robert K; Bechmann, Lars P; Gerken, Guido; Moeller, Lars C; Canbay, Ali

    2015-01-01

    Changes in thyroid hormone levels, mostly as non-thyroidal illness syndrome (NTIS), have been described in many diseases. However, the relationship between acute liver failure (ALF) and thyroid hormone levels has not yet been clarified. The present study evaluates potential correlations of select thyroid functional parameters with ALF. 84 consecutively recruited ALF patients were grouped according to the outcome of ALF (spontaneous recovery: SR; transplantation or death: NSR). TSH, free thyroxine (fT4), free triiodothyronine (fT3), T4, and T3 were determined. More than 50% of patients with ALF presented with abnormal thyroid parameters. These patients had greater risk for an adverse outcome than euthyroid patients. SR patients had significantly higher TSH, T4, and T3 concentrations than NSR patients. Albumin concentrations were significantly higher in SR than in NSR. In vitro T3 treatment was not able to rescue primary human hepatocytes from acetaminophen induced changes in mRNA expression. In patients with ALF, TSH and total thyroid hormone levels differed significantly between SR patients and NSR patients. This might be related to diminished liver-derived transport proteins, such as albumin, in more severe forms of ALF. Thyroid parameters may serve as additional indicators of ALF severity.

  9. Rapid Identification of Cortical Motor Areas in Rodents by High-Frequency Automatic Cortical Stimulation and Novel Motor Threshold Algorithm

    Directory of Open Access Journals (Sweden)

    Mitsuaki Takemi

    2017-10-01

    Full Text Available Cortical stimulation mapping is a valuable tool to test the functional organization of the motor cortex in both basic neurophysiology (e.g., elucidating the process of motor plasticity and clinical practice (e.g., before resecting brain tumors involving the motor cortex. However, compilation of motor maps based on the motor threshold (MT requires a large number of cortical stimulations and is therefore time consuming. Shortening the time for mapping may reduce stress on the subjects and unveil short-term plasticity mechanisms. In this study, we aimed to establish a cortical stimulation mapping procedure in which the time needed to identify a motor area is reduced to the order of minutes without compromising reliability. We developed an automatic motor mapping system that applies epidural cortical surface stimulations (CSSs through one-by-one of 32 micro-electrocorticographic electrodes while examining the muscles represented in a cortical region. The next stimulus intensity was selected according to previously evoked electromyographic responses in a closed-loop fashion. CSS was repeated at 4 Hz and electromyographic responses were submitted to a newly proposed algorithm estimating the MT with smaller number of stimuli with respect to traditional approaches. The results showed that in all tested rats (n = 12 the motor area maps identified by our novel mapping procedure (novel MT algorithm and 4-Hz CSS significantly correlated with the maps achieved by the conventional MT algorithm with 1-Hz CSS. The reliability of the both mapping methods was very high (intraclass correlation coefficients ≧0.8, while the time needed for the mapping was one-twelfth shorter with the novel method. Furthermore, the motor maps assessed by intracortical microstimulation and the novel CSS mapping procedure in two rats were compared and were also significantly correlated. Our novel mapping procedure that determined a cortical motor area within a few minutes could help

  10. Higher frequency of secretor phenotype in O blood group ? its benefits in prevention and/or treatment of some diseases

    OpenAIRE

    Jaff, Mohamad Salih

    2010-01-01

    Mohamad Salih JaffPathology Department, Hawler Medical University (Formerly Salahaddin University), Erbil, Kurdistan Region, IraqAbstract: ABO blood groups and secretor status are important in clinical and forensic medicine and in relation to some diseases. There are geographic and racial differences in their frequencies, but the frequency of secretor status in different ABO blood group systems has not been determined yet. Therefore, the aim of this study was mainly to determine this point. B...

  11. Frequency-selectivity of a thalamocortical relay neuron during Parkinson's disease and deep brain stimulation: a computational study

    NARCIS (Netherlands)

    Cagnan, Hayriye; Cagnan, H.; Meijer, Hil Gaétan Ellart; van Gils, Stephanus A.; Krupa, M.; Heida, Tjitske; Rudolph, Michelle; Wadman, Wyse J.; Martens, Hubert C.F.

    2009-01-01

    In this computational study, we investigated (i) the functional importance of correlated basal ganglia (BG) activity associated with Parkinson's disease (PD) motor symptoms by analysing the effects of globus pallidus internum (GPi) bursting frequency and synchrony on a thalamocortical (TC) relay

  12. Effects of hippocampal high-frequency electrical stimulation in memory formation and their association with amino acid tissue content and release in normal rats.

    Science.gov (United States)

    Luna-Munguía, Hiram; Meneses, Alfredo; Peña-Ortega, Fernando; Gaona, Andres; Rocha, Luisa

    2012-01-01

    Hippocampal high frequency electrical stimulation (HFS) at 130 Hz has been proposed as a therapeutical strategy to control neurological disorders such as intractable temporal lobe epilepsy (TLE). This study was carried out to determine the effects of hippocampal HFS on the memory process and the probable involvement of amino acids. Using the autoshaping task, we found that animals receiving hippocampal HFS showed augmented short-term, but not long-term memory formation, an effect blocked by bicuculline pretreatment and associated with enhanced tissue levels of amino acids in hippocampus. In addition, microdialysis experiments revealed high extracellular levels of glutamate, aspartate, glycine, taurine, and alanine during the application of hippocampal HFS. In contrast, GABA release augmented during HFS and remained elevated for more than 1 h after the stimulation was ended. HFS had minimal effects on glutamine release. The present results suggest that HFS has an activating effect on specific amino acids in normal hippocampus that may be involved in the enhanced short-term memory formation. These data further provide experimental support for the concept that hippocampus may be a promising target for focal stimulation to treat intractable seizures in humans. Copyright © 2010 Wiley Periodicals, Inc., Inc.

  13. Single-cell resolution of intracellular T cell Ca2+ dynamics in response to frequency-based H2O2 stimulation.

    Science.gov (United States)

    Kniss-James, Ariel S; Rivet, Catherine A; Chingozha, Loice; Lu, Hang; Kemp, Melissa L

    2017-03-01

    Adaptive immune cells, such as T cells, integrate information from their extracellular environment through complex signaling networks with exquisite sensitivity in order to direct decisions on proliferation, apoptosis, and cytokine production. These signaling networks are reliant on the interplay between finely tuned secondary messengers, such as Ca 2+ and H 2 O 2 . Frequency response analysis, originally developed in control engineering, is a tool used for discerning complex networks. This analytical technique has been shown to be useful for understanding biological systems and facilitates identification of the dominant behaviour of the system. We probed intracellular Ca 2+ dynamics in the frequency domain to investigate the complex relationship between two second messenger signaling molecules, H 2 O 2 and Ca 2+ , during T cell activation with single cell resolution. Single-cell analysis provides a unique platform for interrogating and monitoring cellular processes of interest. We utilized a previously developed microfluidic device to monitor individual T cells through time while applying a dynamic input to reveal a natural frequency of the system at approximately 2.78 mHz stimulation. Although our network was much larger with more unknown connections than previous applications, we are able to derive features from our data, observe forced oscillations associated with specific amplitudes and frequencies of stimuli, and arrive at conclusions about potential transfer function fits as well as the underlying population dynamics.

  14. Frequency-swept laser light source at 1050 nm with higher bandwidth due to multiple semiconductor optical amplifiers in series

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Thrane, Lars; Andersen, Peter E.

    2009-01-01

    We report on the development of an all-fiber frequency-swept laser light source in the 1050 nm range based on semiconductor optical amplifiers (SOA) with improved bandwidth due to multiple gain media. It is demonstrated that even two SOAs with nearly equal gain spectra can improve the performance...

  15. Low-Frequency Repetitive Transcranial Magnetic Stimulation Ameliorates Cognitive Function and Synaptic Plasticity in APP23/PS45 Mouse Model of Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Zhilin Huang

    2017-09-01

    Full Text Available Alzheimer’s disease (AD is a chronic neurodegenerative disease leading to dementia, which is characterized by progressive memory loss and other cognitive dysfunctions. Recent studies have attested that noninvasive repetitive transcranial magnetic stimulation (rTMS may help improve cognitive function in patients with AD. However, the majority of these studies have focused on the effects of high-frequency rTMS on cognitive function, and little is known about low-frequency rTMS in AD treatment. Furthermore, the potential mechanisms of rTMS on the improvement of learning and memory also remain poorly understood. In the present study, we reported that severe deficits in spatial learning and memory were observed in APP23/PS45 double transgenic mice, a well known mouse model of AD. Furthermore, these behavioral changes were accompanied by the impairment of long-term potentiation (LTP in the CA1 region of hippocampus, a brain region vital to spatial learning and memory. More importantly, 2-week low-frequency rTMS treatment markedly reversed the impairment of spatial learning and memory as well as hippocampal CA1 LTP. In addition, low-frequency rTMS dramatically reduced amyloid-β precursor protein (APP and its C-terminal fragments (CTFs including C99 and C89, as well as β-site APP-cleaving enzyme 1 (BACE1 in the hippocampus. These results indicate that low-frequency rTMS noninvasively and effectively ameliorates cognitive and synaptic functions in a mouse model of AD, and the potential mechanisms may be attributed to rTMS-induced reduction in Aβ neuropathology.

  16. Effects of non-invasive vagus nerve stimulation on attack frequency over time and expanded response rates in patients with chronic cluster headache: a post hoc analysis of the randomised, controlled PREVA study.

    Science.gov (United States)

    Gaul, Charly; Magis, Delphine; Liebler, Eric; Straube, Andreas

    2017-12-01

    In the PREVention and Acute treatment of chronic cluster headache (PREVA) study, attack frequency reductions from baseline were significantly more pronounced with non-invasive vagus nerve stimulation plus standard of care (nVNS + SoC) than with SoC alone. Given the intensely painful and frequent nature of chronic cluster headache attacks, additional patient-centric outcomes, including the time to and level of therapeutic response, were evaluated in a post hoc analysis of the PREVA study. After a 2-week baseline phase, 97 patients with chronic cluster headache entered a 4-week randomised phase to receive nVNS + SoC (n = 48) or SoC alone (n = 49). All 92 patients who continued into a 4-week extension phase received nVNS + SoC. Compared with SoC alone, nVNS + SoC led to a significantly lower mean weekly attack frequency by week 2 of the randomised phase; the attack frequency remained significantly lower in the nVNS + SoC group through week 3 of the extension phase (P cluster headache attack frequency within 2 weeks after its addition to SoC and was associated with significantly higher ≥25%, ≥50%, and ≥75% response rates than SoC alone. The rapid decrease in weekly attack frequency justifies a 4-week trial period to identify responders to nVNS, with a high degree of confidence, among patients with chronic cluster headache.

  17. The Role of Mechanical Stimulation in Recovery of Bone Loss-High versus Low Magnitude and Frequency of Force.

    Science.gov (United States)

    Nagaraja, Mamta Patel; Jo, Hanjoong

    2014-04-02

    Musculoskeletal pathologies associated with decreased bone mass, including osteoporosis and disuse-induced bone loss, affect millions of Americans annually. Microgravity-induced bone loss presents a similar concern for astronauts during space missions. Many pharmaceutical treatments have slowed osteoporosis, and recent data shows promise for countermeasures for bone loss observed in astronauts. Additionally, high magnitude and low frequency impact such as running has been recognized to increase bone and muscle mass under normal but not microgravity conditions. However, a low magnitude and high frequency (LMHF) mechanical load experienced in activities such as postural control, has also been shown to be anabolic to bone. While several clinical trials have demonstrated that LMHF mechanical loading normalizes bone loss in vivo, the target tissues and cells of the mechanical load and underlying mechanisms mediating the responses are unknown. In this review, we provide an overview of bone adaptation under a variety of loading profiles and the potential for a low magnitude loading as a way to counteract bone loss as experienced by astronauts.

  18. The Role of Mechanical Stimulation in Recovery of Bone Loss—High versus Low Magnitude and Frequency of Force

    Directory of Open Access Journals (Sweden)

    Mamta Patel Nagaraja

    2014-04-01

    Full Text Available Musculoskeletal pathologies associated with decreased bone mass, including osteoporosis and disuse-induced bone loss, affect millions of Americans annually. Microgravity-induced bone loss presents a similar concern for astronauts during space missions. Many pharmaceutical treatments have slowed osteoporosis, and recent data shows promise for countermeasures for bone loss observed in astronauts. Additionally, high magnitude and low frequency impact such as running has been recognized to increase bone and muscle mass under normal but not microgravity conditions. However, a low magnitude and high frequency (LMHF mechanical load experienced in activities such as postural control, has also been shown to be anabolic to bone. While several clinical trials have demonstrated that LMHF mechanical loading normalizes bone loss in vivo, the target tissues and cells of the mechanical load and underlying mechanisms mediating the responses are unknown. In this review, we provide an overview of bone adaptation under a variety of loading profiles and the potential for a low magnitude loading as a way to counteract bone loss as experienced by astronauts.

  19. Realisation of four-wave mixing phase matching for frequency components at intracavity stimulated Raman scattering in a calcite crystal

    International Nuclear Information System (INIS)

    Smetanin, Sergei N; Fedin, Aleksandr V; Shurygin, Anton S

    2013-01-01

    The possibilities of implementing four-wave mixing (FWM) phase matching at stimulated Raman scattering (SRS) in a birefringent SRS-active crystal placed in a cavity with highly reflecting mirrors have been theoretically and experimentally investigated. Phase-matching angles providing conditions for five types of phase matching are determined for a calcite crystal. These types are characterised by different combinations of polarisation directions for the interacting waves and ensure FWM generation of either an anti-Stokes wave or the second Stokes SRS component. In agreement with the calculation results, low-threshold generation of the second Stokes SRS component with a wavelength 0.602 μm was observed at angles of incidence on a calcite crystal of 4.8° and 18.2°, under SRS pumping at a wavelength of 0.532 μm. This generation is due to the FWM coupling of the first and second Stokes SRS components with the SRS-pump wave. (nonlinear optical phenomena)

  20. Bimodal atomic force microscopy driving the higher eigenmode in frequency-modulation mode: Implementation, advantages, disadvantages and comparison to the open-loop case.

    Science.gov (United States)

    Ebeling, Daniel; Solares, Santiago D

    2013-01-01

    We present an overview of the bimodal amplitude-frequency-modulation (AM-FM) imaging mode of atomic force microscopy (AFM), whereby the fundamental eigenmode is driven by using the amplitude-modulation technique (AM-AFM) while a higher eigenmode is driven by using either the constant-excitation or the constant-amplitude variant of the frequency-modulation (FM-AFM) technique. We also offer a comparison to the original bimodal AFM method, in which the higher eigenmode is driven with constant frequency and constant excitation amplitude. General as well as particular characteristics of the different driving schemes are highlighted from theoretical and experimental points of view, revealing the advantages and disadvantages of each. This study provides information and guidelines that can be useful in selecting the most appropriate operation mode to characterize different samples in the most efficient and reliable way.

  1. Eating frequency is higher in weight loss maintainers and normal-weight individuals than in overweight individuals.

    Science.gov (United States)

    Bachman, Jessica L; Phelan, Suzanne; Wing, Rena R; Raynor, Hollie A

    2011-11-01

    Eating frequency has been negatively related to body mass index (BMI). The relationship between eating frequency and weight loss maintenance is unknown. This secondary analysis examined eating frequency (self-reported meals and snacks consumed per day) in weight loss maintainers (WLM) who had reduced from overweight/obese to normal weight, normal weight (NW) individuals, and overweight (OW) individuals. Data collected July 2006 to March 2007 in Providence, RI, included three 24-hour dietary recalls (2 weekdays, 1 weekend day) analyzed using Nutrient Data System for Research software from 257 adults (WLM n=96, 83.3% women aged 50.0±11.8 years with BMI 22.1±1.7; NW n=80, 95.0% women aged 46.1±11.5 years with BMI 21.1±1.4; OW n=81, 53.1% women aged 51.4±9.0 years with BMI 34.2±4.1) with plausible intakes. Participant-defined meals and snacks were ≥50 kcal and separated by more than 1 hour. Self-reported physical activity was highest in WLM followed by NW, and then OW (3,097±2,572 kcal/week, 2,062±1,286 kcal/week, and 785±901 kcal/week, respectively; Pmeals consumed (2.7±0.4 meals/day). Eating frequency, particularly in regard to a pattern of three meals and two snacks per day, may be important in weight loss maintenance. Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

  2. Assessment of the frequency of snack and beverages consumption and stimulants intake in children grown up in orphanages in Krakow.

    Science.gov (United States)

    Pysz, Katarzyna; Leszczyńska, Teresa; Kopeć, Aneta

    2015-01-01

    Childhood is a particular period of life, when nutritional habits are emerging, so much attention should be paid to proper dietary habits, which become a nutritional pattern copied in the future. The aim of this study was to evaluate selected dietary habits and preferences in a group of children living in Krakow orphanages (supervising by the Social Welfare Centre in Krakow), by assessing the frequency of snacks and beverages consumptions as well as an intake of beverages with caffeine, alcohol and smoking cigarettes. Studies were performed in the years 2007-2008 in five orphanages located in Krakow. 181 children, 9 to 20 yrs of age, participated in this study. Assessment of dietary habits and preferences was performed based on anonymous questionnaire which included questions about snacking frequency, favorite and most frequently drank beverages without or with caffeine, alcohol and cigarettes smoking. The analysis of nutritional habits showed that the most popular high-calorie snacks were eaten by the youngest children. Children and adolescents asked for the most commonly consumed beverages indicated on fizzy drinks and fruits juice. Among the youngest children (9-12 years old), 5% reported drinking alcohol, 10% of boys smoked cigarettes, 10% of girls and 21% of boys drank coffee. Among the oldest respondents, about 35% declared drinking coffee, 39% girls and 65% boys declared smoking cigarettes, whereas drinking alcohol reported 22 and 38% subjects, respectively. Results obtained in this study, indicate the necessity of intervention, consisting on running training courses and workshops of the assessed population, i.e. children, adolescents and instructing their educators.

  3. Increased Frequency of Peripheral B and T Cells Expressing Granulocyte Monocyte Colony-Stimulating Factor in Rheumatoid Arthritis Patients

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    Anastasia Makris

    2018-01-01

    Full Text Available ObjectivesGranulocyte monocyte colony-stimulating factor (GM-CSF is currently considered a crucial inflammatory mediator and a novel therapeutic target in rheumatoid arthritis (RA, despite the fact that its precise cellular sources remain uncertain. We studied the expression of GM-CSF in peripheral lymphocytes from RA patients and its change with antirheumatic therapies.MethodsIntracellular GM-CSF expression was assessed by flow cytometry in stimulated peripheral B (CD19+ and T (CD3+ cells from RA patients (n = 40, disease (n = 31 including osteoarthritis n = 15, psoriatic arthritis n = 10, and systemic rheumatic diseases n = 6 and healthy (n = 16 controls. The phenotype of GM-CSF+ B cells was assessed as well as longitudinal changes in GM-CSF+ lymphocytes during methotrexate (MTX, n = 10 or anti-tumor necrosis factor (anti-TNF, n = 10 therapy.ResultsAmong untreated RA patients with active disease (Disease Activity Score 28-C-reactive protein = 5.6 ± 0.89 an expanded population of peripheral GM-CSF+ B (4.1 ± 2.2% and T (3.4 ± 1.6% cells was detected compared with both disease (1.7 ± 0.9%, p < 0.0001 and 1.7 ± 1.3%, p < 0.0001, respectively and healthy (0.3 ± 0.2%, p < 0.0001 and 0.6 ± 0.6%, p < 0.0001 controls. RA GM-CSF+ B cells displayed more commonly a plasmablast or transitional phenotype (37.12 ± 18.34% vs. 14.26 ± 9.46%, p = 0.001 and 30.49 ± 15.04% vs. 2.45 ± 1.84%, p < 0.0001, respectively and less a memory phenotype (21.46 ± 20.71% vs. 66.99 ± 16.63%, p < 0.0001 compared to GM-CSF− cells. GM-CSF expression in RA patients did not correlate to disease duration, activity or serological status. Anti-TNF treatment led to a statistically significant decrease in GM-CSF+ B and T cells while MTX had no significant effect.DiscussionThis is the first study showing an expanded population of GM-CSF+ B and T lymphocytes

  4. Frequency up-shift in the stimulated thermal scattering under two-photon absorption in liquids and colloids of metal nanoparticles

    Science.gov (United States)

    Smetanin, I. V.; Erokhin, A. I.; Baranov, A. N.

    2018-07-01

    We report the results of the experimental and theoretical study of stimulated temperature scattering in toluene and hexane solutions of Ag-nanoparticles, as well as in pure toluene in the two-photon absorption regime. A four-wave mixing scheme with two counter-propagating pump waves of the same frequency is utilised to demonstrate the lasing effect and the amplification of the backscattered anti-Stokes signal. For the first time, we have measured anti-Stokes spectral shifts which turn out to appreciably exceed the Rayleigh line widths in those liquids. It is shown that the amplification effect is provided predominantly by thermally induced coherent polarisation oscillations, while the dynamic interference temperature grating causes the formation of a self-induced optical cavity inside the interaction region.

  5. Lean and Obese Zucker Rat Extensor Digitorum Longus Muscle high-frequency electrical stimulation (HFES Data: Regulation of p70S6kinase Associated Proteins

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    Kevin M. Rice

    2018-02-01

    Full Text Available Anaerobic exercise has been advocated as a prescribed treatment for the management of diabetes: however, alterations in exercise-induced signaling remain largely unexplored in the diabetic muscle. Here, we compare the basal and the in situ contraction-induced phosphorylation of the AKT, GSK3beta, mTor, p70s6K, Pten, and Shp2 in the lean and obese (fa/fa Zucker rat Extensor Digitorum Longus (EDL muscle following a single bout of contractile stimuli. This article represents data associated with prior publications from our lab (Katta et al., 2009a, 2009b; Tullgren et al., 1991 [1–3] and concurrent Data in Brief articles (Ginjupalli et al., 2017a, 2017b; Rice et al., 2017a, 2017b [4–7]. Keywords: Diabetes, Skeletal muscle, High-frequency electrical stimulation (HFES, Zucker rat, Extensor Digitorum Longus, p70s6k

  6. Acute Frontal Lobe Dysfunction Following Prefrontal Low-Frequency Repetitive Transcranial Magnetic Stimulation in a Patient with Treatment-Resistant Depression

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    Guilhem Carle

    2017-05-01

    Full Text Available The potential of repetitive transcranial magnetic stimulation (rTMS to treat numerous neurological and psychiatric disorders has been thoroughly studied for the last two decades. Here, we report for the first time, the case of a 65-year-old woman suffering from treatment-resistant depression who developed an acute frontal lobe syndrome following eight sessions of low-frequency rTMS (LF-rTMS to the right dorsolateral prefrontal cortex while also treated with sertraline and mianserin. The pathophysiological mechanisms underlying such an unexpected acute frontal lobe dysfunction are discussed in relation to the therapeutic use of LF-rTMS in combination with pharmacotherapy in depressed patients.

  7. Extremely low frequency electromagnetic fields stimulation modulates autoimmunity and immune responses: a possible immuno-modulatory therapeutic effect in neurodegenerative diseases

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    Fabio Guerriero

    2016-01-01

    Full Text Available Increasing evidence shows that extremely low frequency electromagnetic fields (ELF-EMFs stimulation is able to exert a certain action on autoimmunity and immune cells. In the past, the efficacy of pulsed ELF-EMFs in alleviating the symptoms and the progression of multiple sclerosis has been supported through their action on neurotransmission and on the autoimmune mechanisms responsible for demyelination. Regarding the immune system, ELF-EMF exposure contributes to a general activation of macrophages, resulting in changes of autoimmunity and several immunological reactions, such as increased reactive oxygen species-formation, enhanced phagocytic activity and increased production of chemokines. Transcranial electromagnetic brain stimulation is a non-invasive novel technique used recently to treat different neurodegenerative disorders, in particular Alzheimer's disease. Despite its proven value, the mechanisms through which EMF brain-stimulation exerts its beneficial action on neuronal function remains unclear. Recent studies have shown that its beneficial effects may be due to a neuroprotective effect on oxidative cell damage. On the basis of in vitro and clinical studies on brain activity, modulation by ELF-EMFs could possibly counteract the aberrant pro-inflammatory responses present in neurodegenerative disorders reducing their severity and their onset. The objective of this review is to provide a systematic overview of the published literature on EMFs and outline the most promising effects of ELF-EMFs in developing treatments of neurodegenerative disorders. In this regard, we review data supporting the role of ELF-EMF in generating immune-modulatory responses, neuromodulation, and potential neuroprotective benefits. Nonetheless, we reckon that the underlying mechanisms of interaction between EMF and the immune system are still to be completely understood and need further studies at a molecular level.

  8. The roles of interleukin-1 and RhoA signaling pathway in rat epilepsy model treated with low-frequency electrical stimulation.

    Science.gov (United States)

    Liu, Ai-Hua; Wu, Ya-Ting; Li, Li-Ping; Wang, Yu-Ping

    2018-03-01

    This study aims to explore the correlation between interleukin-1 (IL-1) and epilepsy in rats when treated with low-frequency electrical stimulation via the RhoA/ROCK signaling pathway. Twenty-four SD rats were elected for this study, among which six rats were assigned as the normal group. And 16 rat models with epilepsy were successfully established and assigned into the model group, the ES group and the ES + IL-8 group, with each group comprising of six rats. The seizure frequency and duration was recorded. Electroencephalogram (EEG) power was detected at α1, α2, β, θ, and δ. The mRNA expressions of IL-1β and IL-1R1 were detected using reverse transcription quantitative polymerase chain reaction (RT-qPCR), and the protein expressions of RhoA, ROCK I and ROCK II were detected by western blotting. In comparison with the model group, the seizure frequency duration, the power of δ, θ, α1, α2, and β, the mRNA and protein expressions of IL-1β and IL-1R1, the expressions of RhoA and ROCK I proteins, and the ratio of RhoA protein between membrane and cytosol decreased in the ES group, while the expression of ROCK II increased (all P  0.05). These findings signified that IL-1 might inhibit the efficacy of low-frequency ES for epilepsy via the RhoA/ROCK signaling pathway, which may provide a theoretical basis for clinical treatment of epilepsy. © 2017 Wiley Periodicals, Inc.

  9. High frequency stimulation of the entopeduncular nucleus sets the cortico-basal ganglia network to a new functional state in the dystonic hamster.

    Science.gov (United States)

    Reese, René; Charron, Giselle; Nadjar, Agnès; Aubert, Incarnation; Thiolat, Marie-Laure; Hamann, Melanie; Richter, Angelika; Bezard, Erwan; Meissner, Wassilios G

    2009-09-01

    High frequency stimulation (HFS) of the internal pallidum is effective for the treatment of dystonia. Only few studies have investigated the effects of stimulation on the activity of the cortex-basal ganglia network. We here assess within this network the effect of entopeduncular nucleus (EP) HFS on the expression of c-Fos and cytochrome oxidase subunit I (COI) in the dt(sz)-hamster, a well-characterized model of paroxysmal dystonia. In dt(sz)-hamsters, we identified abnormal activity in motor cortex, basal ganglia and thalamus. These structures have already been linked to the pathophysiology of human dystonia. EP-HFS (i) increased striatal c-Fos expression in controls and dystonic hamsters and (ii) reduced thalamic c-Fos expression in dt(sz)-hamsters. EP-HFS had no effect on COI expression. The present results suggest that EP-HFS induces a new network activity state which may improve information processing and finally reduces the severity of dystonic attacks in dt(sz)-hamsters.

  10. Optimal duration of ultra low frequency-transcutaneous electrical nerve stimulation (ULF-TENS) therapy for muscular relaxation in neuromuscular occlusion: A preliminary clinical study.

    Science.gov (United States)

    Esclassan, Rémi; Rumerio, Anaïs; Monsarrat, Paul; Combadazou, Jean Claude; Champion, Jean; Destruhaut, Florent; Ghrenassia, Christophe

    2017-05-01

    The primary aim of this work was to determine the duration of ultra-low-frequency transcutaneous electrical nerve stimulation (ULF-TENS) application necessary to achieve sufficient relaxation of the masticatory muscles. A secondary aim was to analyze the influence of stimulation on muscle relaxation in pathological subjects and determine whether ULF-TENS has a noteworthy impact on muscle relaxation. Sixteen adult subjects with temporomandibular disorders (TMD) and muscle pain and a group of four control subjects were included in this study. ULF-TENS was applied, and muscular activities of the masseter, temporal, and sternocleidomastoid muscles (SCM) were recorded for 60 min. Significant relaxation was achieved in the TMD group from 20, 40, and 60 min for the temporal, masseter, and SCM muscles (p TENS application would last 40 min to obtain sufficient muscle relaxation both in patients with masticatory system disorders and healthy subjects, a time constraint that is consistent with everyday clinical practice.

  11. σ2-Adaptin Facilitates Basal Synaptic Transmission and Is Required for Regenerating Endo-Exo Cycling Pool Under High-Frequency Nerve Stimulation in Drosophila.

    Science.gov (United States)

    Choudhury, Saumitra Dey; Mushtaq, Zeeshan; Reddy-Alla, Suneel; Balakrishnan, Sruthi S; Thakur, Rajan S; Krishnan, Kozhalmannom S; Raghu, Padinjat; Ramaswami, Mani; Kumar, Vimlesh

    2016-05-01

    The functional requirement of adapter protein 2 (AP2) complex in synaptic membrane retrieval by clathrin-mediated endocytosis is not fully understood. Here we isolated and functionally characterized a mutation that dramatically altered synaptic development. Based on the aberrant neuromuscular junction (NMJ) synapse, we named this mutation angur (a Hindi word meaning "grapes"). Loss-of-function alleles of angur show more than twofold overgrowth in bouton numbers and a dramatic decrease in bouton size. We mapped the angur mutation to σ2-adaptin, the smallest subunit of the AP2 complex. Reducing the neuronal level of any of the subunits of the AP2 complex or disrupting AP2 complex assembly in neurons phenocopied the σ2-adaptin mutation. Genetic perturbation of σ2-adaptin in neurons leads to a reversible temperature-sensitive paralysis at 38°. Electrophysiological analysis of the mutants revealed reduced evoked junction potentials and quantal content. Interestingly, high-frequency nerve stimulation caused prolonged synaptic fatigue at the NMJs. The synaptic levels of subunits of the AP2 complex and clathrin, but not other endocytic proteins, were reduced in the mutants. Moreover, bone morphogenetic protein (BMP)/transforming growth factor β (TGFβ) signaling was altered in these mutants and was restored by normalizing σ2-adaptin in neurons. Thus, our data suggest that (1) while σ2-adaptin facilitates synaptic vesicle (SV) recycling for basal synaptic transmission, its activity is also required for regenerating SVs during high-frequency nerve stimulation, and (2) σ2-adaptin regulates NMJ morphology by attenuating TGFβ signaling. Copyright © 2016 by the Genetics Society of America.

  12. High-frequency stimulation-induced peptide release synchronizes arcuate kisspeptin neurons and excites GnRH neurons

    Science.gov (United States)

    Qiu, Jian; Nestor, Casey C; Zhang, Chunguang; Padilla, Stephanie L; Palmiter, Richard D

    2016-01-01

    Kisspeptin (Kiss1) and neurokinin B (NKB) neurocircuits are essential for pubertal development and fertility. Kisspeptin neurons in the hypothalamic arcuate nucleus (Kiss1ARH) co-express Kiss1, NKB, dynorphin and glutamate and are postulated to provide an episodic, excitatory drive to gonadotropin-releasing hormone 1 (GnRH) neurons, the synaptic mechanisms of which are unknown. We characterized the cellular basis for synchronized Kiss1ARH neuronal activity using optogenetics, whole-cell electrophysiology, molecular pharmacology and single cell RT-PCR in mice. High-frequency photostimulation of Kiss1ARH neurons evoked local release of excitatory (NKB) and inhibitory (dynorphin) neuropeptides, which were found to synchronize the Kiss1ARH neuronal firing. The light-evoked synchronous activity caused robust excitation of GnRH neurons by a synaptic mechanism that also involved glutamatergic input to preoptic Kiss1 neurons from Kiss1ARH neurons. We propose that Kiss1ARH neurons play a dual role of driving episodic secretion of GnRH through the differential release of peptide and amino acid neurotransmitters to coordinate reproductive function. DOI: http://dx.doi.org/10.7554/eLife.16246.001 PMID:27549338

  13. Host-Parasite Interactions in Individuals with Type 1 and 2 Diabetes Result in Higher Frequency of Ascaris lumbricoides and Giardia lamblia in Type 2 Diabetic Individuals

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    Eleuza Rodrigues Machado

    2018-01-01

    Full Text Available Host-parasite interactions in diabetic patients might influence diabetes complications and intestinal parasitosis. The aim was to investigate the occurrence of enteroparasites in individuals with diabetes types 1 and 2. A descriptive study was designed to estimate frequencies of parasites and to compare them in individuals with diabetes types 1 and 2 from two Health Centers and one hospital in the Federal District of Brazil. Patients were allocated to the study by convenience. Three fecal samples of 156 diabetic individuals (120 type 1 and 36 type 2 were analyzed using two parasitological methods. Enteroparasites or commensals frequency in diabetics was 64%. Diabetics infected with up to six species of intestinal parasites or commensals were found. Frequencies of Ascaris lumbricoides and Giardia lamblia were higher in individuals with type 2 diabetes. The lower frequency of A. lumbricoides found in type 1 diabetes may be related to a strong Th2 response to parasites. Autoimmune response developed in type 1 diabetic individuals characterized by the production of Th1 cytokines could explain low frequency of G. lamblia. High frequency of parasites found in type 2 diabetes emphasizes the importance of periodic parasitological examinations in these individuals.

  14. A higher sink competitiveness of the rooting zone and invertases are involved in dark stimulation of adventitious root formation in Petunia hybrida cuttings.

    Science.gov (United States)

    Klopotek, Yvonne; Franken, Philipp; Klaering, Hans-Peter; Fischer, Kerstin; Hause, Bettina; Hajirezaei, Mohammad-Reza; Druege, Uwe

    2016-02-01

    The contribution of carbon assimilation and allocation and of invertases to the stimulation of adventitious root formation in response to a dark pre-exposure of petunia cuttings was investigated, considering the rooting zone (stem base) and the shoot apex as competing sinks. Dark exposure had no effect on photosynthesis and dark respiration during the subsequent light period, but promoted dry matter partitioning to the roots. Under darkness, higher activities of cytosolic and vacuolar invertases were maintained in both tissues when compared to cuttings under light. This was partially associated with higher RNA levels of respective genes. However, activity of cell wall invertases and transcript levels of one cell wall invertase isogene increased specifically in the stem base during the first two days after cutting excision under both light and darkness. During five days after excision, RNA accumulation of four invertase genes indicated preferential expression in the stem base compared to the apex. Darkness shifted the balance of expression of one cytosolic and two vacuolar invertase genes towards the stem base. The results indicate that dark exposure before planting enhances the carbon sink competitiveness of the rooting zone and that expression and activity of invertases contribute to the shift in carbon allocation. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  15. Higher glucose level and systemic oxidative stress decrease the mean velocity index of the retinal artery during flickering light stimulation in type 1 diabetes.

    Science.gov (United States)

    Debelić, Vladimir; Drnovšek Olup, Brigita; Žižek, Bogomir; Skitek, Milan; Jerin, Aleš

    2016-10-31

    To determine whether higher glucose level and systemic oxidative stress decrease mean velocity (MV) index of the central retinal artery (CRA) during flickering light stimulation in type 1 diabetes (T1D). The study was performed in the period from 2008 to 2015 at the University Eye Clinic in Ljubljana. 41 patients with T1D and 37 participants without diabetes were included. MV in the CRA was measured using Doppler ultrasound diagnostics in basal conditions and during 8 Hz flickering light irritation. The plasma levels of glucose, fructosamine, 8-hydroxy-2'-deoxyguanosine (8-OHdG), triglycerides, cholesterol, and low-density lipoprotein (LDL) were measured. Patients with T1D had significantly higher levels of blood glucose (Ptriglycerides (P=0.108), cholesterol (P=0.531), and LDL (P=0.645) between the groups. Patients with T1D also had a significantly lower MV index in the CRA (1.11±0.15 vs 1.24±0.23; P=0.010). In the T1D group, a significant negative correlation was found between the level of glucose (r=0.58; Pindex in the CRA. At the same time, in this group fructosamine and 8-OHdG levels had a separate effect on the MV index (adjusted R2=0.38, Pglucose levels, the medium-term glucose level, and systemic oxidative stress could importantly reduce retinal vasodilatation during flickering light irritation in patients with T1D.

  16. r-CBF brain SPET before surgery and during subthalamic nuclei (STN) high frequency stimulation (DBS) in Parkinson's Disease

    International Nuclear Information System (INIS)

    Gerundini, P.; Benti, R.; De Notaris, A.; Ferrari, M.; Raimondi, A.; Mariani, C.; Antonini, A.; Pezzoli, G.; Gaini, S.M.

    2002-01-01

    Deep brain stimulation (DBS) of the subthalamic nuclei (STN) can improve motor symptoms and reduces the need for medical therapy in severe Parkinson's Disease (PD). Moreover, DBS can affect, as the medical treatment, cerebral perfusion/metabolism even in cortical/subcortical areas not primarily involved in PD motor symptoms. Aim of the study was the assessment of r-CBF changes by mean of brain SPECT in severe PD .before surgery and during DBS of the STN. Methods. 14 PD patients (duration 15.2±5.1 ys; H and Y off-score 3.6±0.7) underwent STN electrode implantation. Residual motor dysfunction was assessed by UPDRS score up to one year after surgery. SPECT was performed after i.v. injection of Tc-99m ECD (740 MBq) in PD group before and 6-9 months after surgery and in 13 age matched normals. Standardized ROIs templates were applied in brain sections to generate perfusion ratios in the cerebral cortex and basal ganglia. Statistical Parametric Mapping (SPM) analysis of SPET studies was also obtained. Results: 6 months after surgery the mean UPDRS score improvement was 48.8±26.1% (DBS on) vs pre surgery. 8 patients (R+) had UPDRS improvement >50% (mean 67.7±8.8%); 6 patients (R-) had score improvement <50% (mean 22.9±18.9%). Before surgery, motor dysfunction during therapy was similar in R+ and R- groups (mean UPDRS 19.8±8.2 vs. 21.3±9.6). During BDS, UPDRS mean score without medical therapy was lower in R+ (15.6±5.6) vs. R- (35.0±12.4; p<0.001). ROIs and SPM analysis of pre-surgery SPET studies showed significant hypoperfusion (p<0.01) in the occipital gyri of PD vs control groups. No significant differences were found by comparing pre/post surgery SPECT patterns in whole PD group. However, in R- group SPECT showed significant hypoperfusion in pre-frontal areas, parietal and occipital gyri vs R+ patients (p<0.02) and controls (p<0.01). Before surgery, R+ group had borderline occipital hypoperfusion (p=0.04) and mild increase of putaminal perfusion (p=0.03) vs

  17. Higher plant availability and reduced reactor scram frequency in PWRs by appropriate system and I and C design

    International Nuclear Information System (INIS)

    Frei, G.; Weber, J.

    1987-01-01

    High plant availability and reliability are guaranteed by appropriate design of reactor and BOP systems, this including the plant I and C systems. It is of advantage to have design, construction and commissioning of the plant concentrated in the hands of a single company to avoid interface problems between the different areas of the plant. The integrated overall control concept developed by KWU with control, limitation and protection systems as well as optimized operational and monitoring systems assisted by instrumentation channel redundance and logic for selection of the second highest (or second lowest) signal value as appropriate for comparison with limitation setpoints, minimize the severity of transients. This results in a reduction in the frequency of reactor scrams and of unnecessary actuation of safety systems. Dynamic plant behavior is described for a number of examples where the improved plant behavior resulting from the above design features enhances plant availability

  18. A novel MR-compatible sensor to assess active medical device safety: stimulation monitoring, rectified radio frequency pulses, and gradient-induced voltage measurements.

    Science.gov (United States)

    Barbier, Thérèse; Aissani, Sarra; Weber, Nicolas; Pasquier, Cédric; Felblinger, Jacques

    2018-03-30

    To evaluate the function of an active implantable medical device (AIMD) during magnetic resonance imaging (MRI) scans. The induced voltages caused by the switching of magnetic field gradients and rectified radio frequency (RF) pulse were measured, along with the AIMD stimulations. An MRI-compatible voltage probe with a bandwidth of 0-40 kHz was designed. Measurements were carried out both on the bench with an overvoltage protection circuit commonly used for AIMD and with a pacemaker during MRI scans on a 1.5 T (64 MHz) MR scanner. The sensor exhibits a measurement range of ± 15 V with an amplitude resolution of 7 mV and a temporal resolution of 10 µs. Rectification was measured on the bench with the overvoltage protection circuit. Linear proportionality was confirmed between the induced voltage and the magnetic field gradient slew rate. The pacemaker pacing was recorded successfully during MRI scans. The characteristics of this low-frequency voltage probe allow its use with extreme RF transmission power and magnetic field gradient positioning for MR safety test of AIMD during MRI scans.

  19. HIV exposed seronegative (HESN compared to HIV infected individuals have higher frequencies of telomeric Killer Immunoglobulin-like Receptor (KIR B motifs; Contribution of KIR B motif encoded genes to NK cell responsiveness.

    Directory of Open Access Journals (Sweden)

    Elise Jackson

    Full Text Available Previously, we showed that Killer Immunoglobulin-like Receptor (KIR3DS1 homozygotes (hmz are more frequent in HIV exposed seronegative (HESN than in recently HIV infected (HIV+ individuals. KIR3DS1 encodes an activating Natural Killer (NK cell receptor (NKR. The link between KIR genotype and HIV outcomes likely arises from the function that NK cells acquire through expression of particular NKRs. An initial screen of 97 HESN and 123 HIV+ subjects for the frequency of KIR region gene carriage observed between-group differences for several telomeric KIR region loci. In a larger set of up to 106 HESN and 439 HIV+ individuals, more HESN than HIV+ subjects were KIR3DS1 homozygotes, lacked a full length KIR2DS4 gene and carried the telomeric group B KIR haplotype motif, TB01. TB01 is characterized by the presence of KIR3DS1, KIR2DL5A, KIR2DS3/5 and KIR2DS1, in linkage disequilibrium with each other. We assessed which of the TB01 encoded KIR gene products contributed to NK cell responsiveness by stimulating NK cells from 8 HIV seronegative KIR3DS1 and TB01 motif homozygotes with 721.221 HLA null cells and evaluating the frequency of KIR3DS1+/-KIR2DL5+/-, KIR3DS1+/-KIR2DS1+/-, KIR3DS1+/-KIR2DS5+/- NK cells secreting IFN-γ and/or expressing CD107a. A higher frequency of NK cells expressing, versus not, KIR3DS1 responded to 721.221 stimulation. KIR2DL5A+, KIR2DS1+ and KIR2DS5+ NK cells did not contribute to 721.221 responses or modulate those by KIR3DS1+ NK cells. Thus, of the TB01 KIR gene products, only KIR3DS1 conferred responsiveness to HLA-null stimulation, demonstrating its ligation can activate ex vivo NK cells.

  20. Effects of sertraline on brain current source of the high beta frequency band: analysis of electroencephalography during audiovisual erotic stimulation in males with premature ejaculation.

    Science.gov (United States)

    Kwon, O Y; Kam, S C; Choi, J H; Do, J M; Hyun, J S

    2011-01-01

    To identify the effects of sertraline, a selective serotonin reuptake inhibitor, for the treatment of premature ejaculation (PE), changes in brain current-source density (CSD) of the high beta frequency band (22-30 Hz) induced by sertraline administration were investigated during audiovisual erotic stimulation. Eleven patients with PE (36.9±7.8 yrs) and 11 male volunteers (24.2±1.9 years) were enrolled. Scalp electroencephalography (EEG) was conducted twice: once before sertraline administration and then again 4 h after the administration of 50 mg sertraline. Statistical non-parametric maps were obtained using the EEG segments to detect the current-density differences in the high beta frequency bands (beta-3, 22-30 Hz) between the EEGs before and after sertraline administration in the patient group and between the patient group and controls after the administration of sertraline during the erotic video sessions. Comparing between before and after sertraline administration in the patients with PE, the CSD of the high beta frequency band at 4 h after sertraline administration increased significantly in both superior frontal gyri and the right medial frontal gyrus (P<0.01). The CSD of the beta-3 band of the patients with PE were less activated significantly in the middle and superior temporal gyrus, lingual and fusiform gyrus, inferior occipital gyrus and cuneus of the right cerebral hemisphere compared with the normal volunteers 4 h after sertraline administration (P<0.01). In conclusion, sertraline administration increased the CSD in both the superior frontal and right middle temporal gyrus in patients with PE. The results suggest that the increased neural activity in these particular cerebral regions after sertraline administration may be associated with inhibitory effects on ejaculation in patients with PE.

  1. Raclopride or high-frequency stimulation of the subthalamic nucleus stops cocaine-induced motor stereotypy and restores related alterations in prefrontal basal ganglia circuits.

    Science.gov (United States)

    Aliane, Verena; Pérez, Sylvie; Deniau, Jean-Michel; Kemel, Marie-Louise

    2012-11-01

    Motor stereotypy is a key symptom of various neurological or neuropsychiatric disorders. Neuroleptics or the promising treatment using deep brain stimulation stops stereotypies but the mechanisms underlying their actions are unclear. In rat, motor stereotypies are linked to an imbalance between prefrontal and sensorimotor cortico-basal ganglia circuits. Indeed, cortico-nigral transmission was reduced in the prefrontal but not sensorimotor basal ganglia circuits and dopamine and acetylcholine release was altered in the prefrontal but not sensorimotor territory of the dorsal striatum. Furthermore, cholinergic transmission in the prefrontal territory of the dorsal striatum plays a crucial role in the arrest of motor stereotypy. Here we found that, as previously observed for raclopride, high-frequency stimulation of the subthalamic nucleus (HFS STN) rapidly stopped cocaine-induced motor stereotypies in rat. Importantly, raclopride and HFS STN exerted a strong effect on cocaine-induced alterations in prefrontal basal ganglia circuits. Raclopride restored the cholinergic transmission in the prefrontal territory of the dorsal striatum and the cortico-nigral information transmissions in the prefrontal basal ganglia circuits. HFS STN also restored the N-methyl-d-aspartic-acid-evoked release of acetylcholine and dopamine in the prefrontal territory of the dorsal striatum. However, in contrast to raclopride, HFS STN did not restore the cortico-substantia nigra pars reticulata transmissions but exerted strong inhibitory and excitatory effects on neuronal activity in the prefrontal subdivision of the substantia nigra pars reticulata. Thus, both raclopride and HFS STN stop cocaine-induced motor stereotypy, but exert different effects on the related alterations in the prefrontal basal ganglia circuits. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

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

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    Konrad Waldowski

    2012-01-01

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

  3. Will greenhouse gas-induced warming over the next 50 years lead to higher frequency and greater intensity of hurricanes?

    International Nuclear Information System (INIS)

    Bengtsson, L.; Botzet, M.; Esch, M.

    1994-01-01

    The use of a high resolution atmospheric model at T106 resolution, for studying the influence on greenhouse warming on tropical storm climatology, is investigated. The same method for identifying the storms has been used as in a previous study by Bengtsson et al (1994). The sea surface temperature anomalies have been taken from a previous climate change experiment, obtained with a low resolution ocean-atmosphere coupled model. The global distribution of the storms agree in their geographical position and seasonal variability with that of the present climate, but the number of storms is significantly reduced, particularly at the Southern hemisphere. The main reason to this is related to increased tropospheric stability, associated with increased warming at the upper troposphere and changes in the large scale circulation such as a weaker Hadley circulation and stronger upper air westerlies. The surface winds in the tropics are generally weaker and evaporation is also somewhat reduced, in spite of higher sea surface temperatures. (orig.)

  4. Low-frequency repetitive transcranial magnetic stimulation (rTMS) affects event-related potential measures of novelty processing in autism.

    Science.gov (United States)

    Sokhadze, Estate; Baruth, Joshua; Tasman, Allan; Mansoor, Mehreen; Ramaswamy, Rajesh; Sears, Lonnie; Mathai, Grace; El-Baz, Ayman; Casanova, Manuel F

    2010-06-01

    In our previous study on individuals with autism spectrum disorder (ASD) (Sokhadze et al., Appl Psychophysiol Biofeedback 34:37-51, 2009a) we reported abnormalities in the attention-orienting frontal event-related potentials (ERP) and the sustained-attention centro-parietal ERPs in a visual oddball experiment. These results suggest that individuals with autism over-process information needed for the successful differentiation of target and novel stimuli. In the present study we examine the effects of low-frequency, repetitive Transcranial Magnetic Stimulation (rTMS) on novelty processing as well as behavior and social functioning in 13 individuals with ASD. Our hypothesis was that low-frequency rTMS application to dorsolateral prefrontal cortex (DLFPC) would result in an alteration of the cortical excitatory/inhibitory balance through the activation of inhibitory GABAergic double bouquet interneurons. We expected to find post-TMS differences in amplitude and latency of early and late ERP components. The results of our current study validate the use of low-frequency rTMS as a modulatory tool that altered the disrupted ratio of cortical excitation to inhibition in autism. After rTMS the parieto-occipital P50 amplitude decreased to novel distracters but not to targets; also the amplitude and latency to targets increased for the frontal P50 while decreasing to non-target stimuli. Low-frequency rTMS minimized early cortical responses to irrelevant stimuli and increased responses to relevant stimuli. Improved selectivity in early cortical responses lead to better stimulus differentiation at later-stage responses as was made evident by our P3b and P3a component findings. These results indicate a significant change in early, middle-latency and late ERP components at the frontal, centro-parietal, and parieto-occipital regions of interest in response to target and distracter stimuli as a result of rTMS treatment. Overall, our preliminary results show that rTMS may prove to

  5. Electrical stimulation of the midbrain excites the auditory cortex asymmetrically.

    Science.gov (United States)

    Quass, Gunnar Lennart; Kurt, Simone; Hildebrandt, Jannis; Kral, Andrej

    2018-05-17

    Auditory midbrain implant users cannot achieve open speech perception and have limited frequency resolution. It remains unclear whether the spread of excitation contributes to this issue and how much it can be compensated by current-focusing, which is an effective approach in cochlear implants. The present study examined the spread of excitation in the cortex elicited by electric midbrain stimulation. We further tested whether current-focusing via bipolar and tripolar stimulation is effective with electric midbrain stimulation and whether these modes hold any advantage over monopolar stimulation also in conditions when the stimulation electrodes are in direct contact with the target tissue. Using penetrating multielectrode arrays, we recorded cortical population responses to single pulse electric midbrain stimulation in 10 ketamine/xylazine anesthetized mice. We compared monopolar, bipolar, and tripolar stimulation configurations with regard to the spread of excitation and the characteristic frequency difference between the stimulation/recording electrodes. The cortical responses were distributed asymmetrically around the characteristic frequency of the stimulated midbrain region with a strong activation in regions tuned up to one octave higher. We found no significant differences between monopolar, bipolar, and tripolar stimulation in threshold, evoked firing rate, or dynamic range. The cortical responses to electric midbrain stimulation are biased towards higher tonotopic frequencies. Current-focusing is not effective in direct contact electrical stimulation. Electrode maps should account for the asymmetrical spread of excitation when fitting auditory midbrain implants by shifting the frequency-bands downward and stimulating as dorsally as possible. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Primed low-frequency repetitive transcranial magnetic stimulation and constraint-induced movement therapy in pediatric hemiparesis: a randomized controlled trial.

    Science.gov (United States)

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

    2014-01-01

    The aim of this study was to determine the feasibility and efficacy of five treatments of 6 Hz primed, low-frequency, repetitive transcranial magnetic stimulation (rTMS) combined with constraint-induced movement therapy (CIMT) to promote recovery of the paretic hand in children with congenital hemiparesis. Nineteen children with congenital hemiparesis aged between 8 and 17 years (10 males, nine females; mean age 10 years 10 months, SD 2 years 10 months; Manual Ability Classification Scale levels I-III) underwent five sessions of either real rTMS (n=10) or sham rTMS (n=9) alternated daily with CIMT. CIMT consisted of 13 days of continuous long-arm casting with five skin-check sessions. Each child received a total of 10 hours of one-to-one therapy. The primary outcome measure was the Assisting Hand Assessment (AHA) and the secondary outcome variables were the Canadian Occupational Performance Measure (COPM) and stereognosis. A Wilcoxon signed-rank sum test was used to analyze differences between pre- and post-test scores within the groups. Analysis of covariance was used to compute mean differences between groups adjusting for baseline. Fisher's exact test was used to compare individual change in AHA raw scores with the smallest detectable difference (SDD) of 4 points. All participants receiving treatment finished the study. Improvement in AHA differed significantly between groups (p=0.007). No significant differences in the secondary outcome measures were found. Eight out of 10 participants in the rTMS/CIMT group showed improvement greater than the SDD, but only two out of nine in the sham rTMS/CIMT group showed such improvement (p=0.023). No serious adverse events occurred. Primed, low-frequency rTMS combined with CIMT appears to be safe, feasible, and efficacious in pediatric hemiparesis. Larger clinical trials are now indicated. © 2013 Mac Keith Press.

  7. Efficacy of intermittent Theta Burst Stimulation (iTBS) and 10-Hz high-frequency repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant unipolar depression: study protocol for a randomised controlled trial.

    Science.gov (United States)

    Bulteau, Samuel; Sébille, Veronique; Fayet, Guillemette; Thomas-Ollivier, Veronique; Deschamps, Thibault; Bonnin-Rivalland, Annabelle; Laforgue, Edouard; Pichot, Anne; Valrivière, Pierre; Auffray-Calvier, Elisabeth; Fortin, June; Péréon, Yann; Vanelle, Jean-Marie; Sauvaget, Anne

    2017-01-13

    The treatment of depression remains a challenge since at least 40% of patients do not respond to initial antidepressant therapy and 20% present chronic symptoms (more than 2 years despite standard treatment administered correctly). Repetitive transcranial magnetic stimulation (rTMS) is an effective adjuvant therapy but still not ideal. Intermittent Theta Burst Stimulation (iTBS), which has only been used recently in clinical practice, could have a faster and more intense effect compared to conventional protocols, including 10-Hz high-frequency rTMS (HF-rTMS). However, no controlled study has so far highlighted the superiority of iTBS in resistant unipolar depression. This paper focuses on the design of a randomised, controlled, double-blind, single-centre study with two parallel arms, carried out in France, in an attempt to assess the efficacy of an iTBS protocol versus a standard HF- rTMS protocol. Sixty patients aged between 18 and 75 years of age will be enrolled. They must be diagnosed with major depressive disorder persisting despite treatment with two antidepressants at an effective dose over a period of 6 weeks during the current episode. The study will consist of two phases: a treatment phase comprising 20 sessions of rTMS to the left dorsolateral prefrontal cortex, localised via a neuronavigation system and a 6-month longitudinal follow-up. The primary endpoint will be the number of responders per group, defined by a decrease of at least 50% in the initial score on the Montgomery and Asberg Rating Scale (MADRS) at the end of rTMS sessions. The secondary endpoints will be: response rate 1 month after rTMS sessions; number of remissions defined by a MADRS score of iTBS superiority in the management of unipolar depression and we will discuss its effect over time. In case of a significant increase in the number of therapeutic responses with a prolonged effect, the iTBS protocol could be considered a first-line protocol in resistant unipolar depression

  8. Sleep Deprivation in Young and Healthy Subjects Is More Sensitively Identified by Higher Frequencies of Electrodermal Activity than by Skin Conductance Level Evaluated in the Time Domain

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    Hugo F. Posada-Quintero

    2017-06-01

    Full Text Available We analyzed multiple measures of the autonomic nervous system (ANS based on electrodermal activity (EDA and heart rate variability (HRV for young healthy subjects undergoing 24-h sleep deprivation. In this study, we have utilized the error awareness test (EAT every 2 h (13 runs total, to evaluate the deterioration of performance. EAT consists of trials where the subject is presented words representing colors. Subjects are instructed to press a button (“Go” trials or withhold the response if the word presented and the color of the word mismatch (“Stroop No-Go” trial, or the screen is repeated (“Repeat No-Go” trials. We measured subjects' (N = 10 reaction time to the “Go” trials, and accuracy to the “Stroop No-Go” and “Repeat No-Go” trials. Simultaneously, changes in EDA and HRV indices were evaluated. Furthermore, the relationship between reactiveness and vigilance measures and indices of sympathetic control based on HRV were analyzed. We found the performance improved to a stable level from 6 through 16 h of deprivation, with a subsequently sustained impairment after 18 h. Indices of higher frequencies of EDA related more to vigilance measures, whereas lower frequencies index (skin conductance leve, SCL measured the reactiveness of the subject. We conclude that indices of EDA, including those of the higher frequencies, termed TVSymp, EDASymp, and NSSCRs, provide information to better understand the effect of sleep deprivation on subjects' autonomic response and performance.

  9. An investigation into the magnitude of the current window and perception of transcutaneous electrical nerve stimulation (TENS) sensation at various frequencies and body sites in healthy human participants.

    Science.gov (United States)

    Hughes, Nicola; Bennett, Michael I; Johnson, Mark I

    2013-02-01

    Strong nonpainful transcutaneous electrical nerve stimulation (TENS) is prerequisite to a successful analgesic outcome although the ease with which this sensation is achieved is likely to depend on the magnitude of current amplitude (mA) between sensory detection threshold (SDT) and pain threshold, that is, the current window. To measure the current window and participant's perception of the comfort of the TENS sensation at different body sites. A repeated measure cross-over study was conducted using 30 healthy adult volunteers. Current amplitudes (mA) of TENS [2 pulses per second (pps); 30 pps; 80 pps] at SDT, pain threshold, and strong nonpainful intensities were measured at the tibia (bone), knee joint (connective tissue), lower back [paraspinal (skeletal) muscle], volar surface of forearm (nerve) and waist (fat). The amplitude to achieve a strong nonpainful intensity was represented as a percentage of the current window. Data were analyzed using repeated measures analysis of variance. Effects were detected for body site and frequency for SDT (PTENS as a percentage of the current window (P=0.002, PTENS as most comfortable at the lower back (PTENS is most comfortable and easiest to titrate to a strong nonpainful intensity when applied over areas of muscle and soft tissue.

  10. Effects of low-frequency repetitive transcranial magnetic stimulation on upper extremity motor recovery and functional outcomes in chronic stroke patients: A randomized controlled trial.

    Science.gov (United States)

    Aşkın, Ayhan; Tosun, Aliye; Demirdal, Ümit Seçil

    2017-06-01

    Repetitive transcranial magnetic stimulation (rTMS) was suggested as a preconditioning method that would increase brain plasticity and that it would be optimal to combine rTMS with intensive rehabilitation. To assess the efficacy of inhibitory rTMS on upper extremity motor recovery and functional outcomes in chronic ischemic stroke patients. In this randomized controlled trial, experimental group received low-frequency (LF) rTMS to the primary motor cortex of the unaffected side + physical therapy (PT), and control group received PT. No statistically significant difference was found in baseline demographical and clinical characteristics of the subjects including stroke severity or severity of paralysis prior to intervention. There were statistically significant improvements in all clinical outcome measures except for the Brunnstrom Recovery Stages. Fugl-Meyer Assessment, Box and Block test, motor and total scores of Functional Independence Measurement (FIM), and Functional Ambulation Scale (FAS) scores were significantly increased in both groups, however, these changes were significantly greater in the rTMS group except for FAS score. FIM cognitive scores and standardized mini-mental test scores were significantly increased and distal and hand Modified Ashworth Scale scores were significantly decreased only in the rTMS group (p functional, and cognitive deficits in chronic stroke. Further studies with a larger number of patients with longer follow-up periods are needed to establish its effectiveness in stroke rehabilitation.

  11. Combined Electric and Acoustic Stimulation With Hearing Preservation: Effect of Cochlear Implant Low-Frequency Cutoff on Speech Understanding and Perceived Listening Difficulty.

    Science.gov (United States)

    Gifford, René H; Davis, Timothy J; Sunderhaus, Linsey W; Menapace, Christine; Buck, Barbara; Crosson, Jillian; O'Neill, Lori; Beiter, Anne; Segel, Phil

    The primary objective of this study was to assess the effect of electric and acoustic overlap for speech understanding in typical listening conditions using semidiffuse noise. This study used a within-subjects, repeated measures design including 11 experienced adult implant recipients (13 ears) with functional residual hearing in the implanted and nonimplanted ear. The aided acoustic bandwidth was fixed and the low-frequency cutoff for the cochlear implant (CI) was varied systematically. Assessments were completed in the R-SPACE sound-simulation system which includes a semidiffuse restaurant noise originating from eight loudspeakers placed circumferentially about the subject's head. AzBio sentences were presented at 67 dBA with signal to noise ratio varying between +10 and 0 dB determined individually to yield approximately 50 to 60% correct for the CI-alone condition with full CI bandwidth. Listening conditions for all subjects included CI alone, bimodal (CI + contralateral hearing aid), and bilateral-aided electric and acoustic stimulation (EAS; CI + bilateral hearing aid). Low-frequency cutoffs both below and above the original "clinical software recommendation" frequency were tested for all patients, in all conditions. Subjects estimated listening difficulty for all conditions using listener ratings based on a visual analog scale. Three primary findings were that (1) there was statistically significant benefit of preserved acoustic hearing in the implanted ear for most overlap conditions, (2) the default clinical software recommendation rarely yielded the highest level of speech recognition (1 of 13 ears), and (3) greater EAS overlap than that provided by the clinical recommendation yielded significant improvements in speech understanding. For standard-electrode CI recipients with preserved hearing, spectral overlap of acoustic and electric stimuli yielded significantly better speech understanding and less listening effort in a laboratory-based, restaurant

  12. Alterations of the amplitude of low-frequency fluctuation in healthy subjects with theta-burst stimulation of the cortex of the suprahyoid muscles.

    Science.gov (United States)

    Ruan, Xiuhang; Xu, Guangqing; Gao, Cuihua; Liu, Lingling; Liu, Yanli; Jiang, Lisheng; Chen, Xin; Yu, Shaode; Jiang, Xinqing; Lan, Yue; Wei, Xinhua

    2017-12-04

    Theta burst stimulation (TBS) has emerged as a promising tool for the treatment of swallowing disorders; however, the short-term after-effects of brain activation induced by TBS remain unknown. Here, we measured the changes in spontaneous brain activation using the amplitude of low-frequency fluctuation (ALFF) approach in subjects who underwent different TBS protocols. Sixty right-handed healthy participants (male, n=30; female, n=30; mean age=23.5y) were recruited in this study and randomly assigned to three groups that underwent three different TBS protocols. In group 1, continuous TBS (cTBS) was positioned on the left hemisphere of the suprahyoid muscle cortex. For group 2, intermittent TBS (iTBS) was placed on the left hemisphere of the suprahyoid muscle cortex. Group 3 underwent combined cTBS/iTBS protocols in which iTBS on the right hemisphere was performed immediately after completing cTBS on the left suprahyoid muscle cortex. Compared to pre-TBS, post-cTBS showed decreased ALFF in the anterior cingulate gyrus (BA 32); post-iTBS induced an increase in ALFF in the bilateral precuneus (BA 7); and post-cTBS/iTBS induced a decrease in ALFF in the brainstem, and resulted in increased ALFF in the middle cingulate gyrus (BA 24) as well as the left precentral gyrus (BA 6). Compared the effect of post-TBS protocols, increased ALFF was found in left posterior cerebellum lobe and left inferior parietal lobule (BA 40) (post-cTBS vs post-iTBS), and decreased ALFF exhibited in paracentral lobule (BA 4) (post-iTBS vs post-cTBS/iTBS). These findings indicate that multiple brain areas involved in swallowing regulation after stimulation of TBS over the suprahyoid muscles. cTBS induces decreased after-effects while iTBS results in increased after-effects on spontaneous brain activation. Moreover, iTBS can eliminate the after-effects of cTBS applied on the contralateral swallowing cortex and alter the activity of contralateral motor cortex and brainstem. Our findings provide a

  13. Effectiveness of fixed-site high-frequency transcutaneous electrical nerve stimulation in chronic pain: a large-scale, observational study

    Directory of Open Access Journals (Sweden)

    Kong X

    2018-04-01

    Full Text Available Xuan Kong, Shai N Gozani NeuroMetrix, Inc., Waltham, MA, USA Objective: The objective of this study was to assess the effectiveness of fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS in a real-world chronic pain sample. Background: There is a need for nonpharmacological treatment options for chronic pain. FS-TENS improved multisite chronic pain in a previous interventional study. Large observational studies are needed to further characterize its effectiveness. Methods: This retrospective observational cohort study examined changes in chronic pain measures following 60 days of FS-TENS use. The study data were obtained from FS-TENS users who uploaded their device utilization and clinical data to an online database. The primary outcome measures were changes in pain intensity and pain interference with sleep, activity, and mood on an 11-point numerical rating scale. Dose–response associations were evaluated by stratifying subjects into low (≤30 days, intermediate (31–56 days, and high (≥57 days utilization subgroups. FS-TENS effectiveness was quantified by baseline to follow-up group differences and a responder analysis (≥30% improvement in pain intensity or ≥2-point improvement in pain interference domains. Results: Utilization and clinical data were collected from 11,900 people using FS-TENS for chronic pain, with 713 device users meeting the inclusion and exclusion criteria. Study subjects were generally older, overweight adults. Subjects reported multisite pain with a mean of 4.8 (standard deviation [SD] 2.5 pain sites. A total of 97.2% of subjects identified low back and/or lower extremity pain, and 72.9% of subjects reported upper body pain. All pain measures exhibited statistically significant group differences from baseline to 60-day follow-up. The largest changes were pain interference with activity (−0.99±2.69 points and mood (−1.02±2.78 points. A total of 48.7% of subjects exhibited a

  14. Females with paired occurrence of cancers in the UADT and genital region have a higher frequency of either Glutathione S-transferase M1/T1 null genotype

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    Jhavar Sameer G

    2005-03-01

    Full Text Available Abstract Upper Aero digestive Tract (UADT is the commonest site for the development of second cancer in females after primary cervical cancer. Glutathione S-transferase (GSTM1 and / or T1 null genotype modulates the risk of developing UADT cancer (primary as well as second cancer. The aim of this study was to evaluate the difference in GST null genotype frequencies in females with paired cancers in the UADT and genital region as compared to females with paired cancers in the UADT and non-genital region. Forty-nine females with a cancer in the UADT and another cancer (at all sites-genital and non-genital were identified from a database of patients with multiple primary neoplasms and were analyzed for the GSTM1 and T1 genotype in addition to known factors such as age, tobacco habits, alcohol habits and family history of cancer. Frequencies of GSTM1 null, GSTT1 null, and either GSTM1/T1 null were higher in females with paired occurrence of cancer in the UADT and genital site (54%, 33% and 75% respectively in comparison to females with paired occurrence of cancer in the UADT and non-genital sites (22%, 6% and 24% respectively. The significantly higher inherited frequency of either GSTM1/T1 null genotype in females with a paired occurrence of cancers in UADT and genital region (p = 0.01, suggests that these females are more susceptible to damage by carcinogens as compared to females who have UADT cancers in association with cancers at non-genital sites.

  15. High-frequency stimulation of the subthalamic nucleus modifies the expression of vesicular glutamate transporters in basal ganglia in a rat model of Parkinson's disease.

    Science.gov (United States)

    Favier, Mathieu; Carcenac, Carole; Drui, Guillaume; Boulet, Sabrina; El Mestikawy, Salah; Savasta, Marc

    2013-12-05

    It has been suggested that glutamatergic system hyperactivity may be related to the pathogenesis of Parkinson's disease (PD). Vesicular glutamate transporters (VGLUT1-3) import glutamate into synaptic vesicles and are key anatomical and functional markers of glutamatergic excitatory transmission. Both VGLUT1 and VGLUT2 have been identified as definitive markers of glutamatergic neurons, but VGLUT 3 is also expressed by non glutamatergic neurons. VGLUT1 and VGLUT2 are thought to be expressed in a complementary manner in the cortex and the thalamus (VL/VM), in glutamatergic neurons involved in different physiological functions. Chronic high-frequency stimulation (HFS) of the subthalamic nucleus (STN) is the neurosurgical therapy of choice for the management of motor deficits in patients with advanced PD. STN-HFS is highly effective, but its mechanisms of action remain unclear. This study examines the effect of STN-HFS on VGLUT1-3 expression in different brain nuclei involved in motor circuits, namely the basal ganglia (BG) network, in normal and 6-hydroxydopamine (6-OHDA) lesioned rats. Here we report that: 1) Dopamine(DA)-depletion did not affect VGLUT1 and VGLUT3 expression but significantly decreased that of VGLUT2 in almost all BG structures studied; 2) STN-HFS did not change VGLUT1-3 expression in the different brain areas of normal rats while, on the contrary, it systematically induced a significant increase of their expression in DA-depleted rats and 3) STN-HFS reversed the decrease in VGLUT2 expression induced by the DA-depletion. These results show for the first time a comparative analysis of changes of expression for the three VGLUTs induced by STN-HFS in the BG network of normal and hemiparkinsonian rats. They provide evidence for the involvement of VGLUT2 in the modulation of BG cicuits and in particular that of thalamostriatal and thalamocortical pathways suggesting their key role in its therapeutic effects for alleviating PD motor symptoms.

  16. Excitation of higher radial modes of azimuthal surface waves in the electron cyclotron frequency range by rotating relativistic flow of electrons in cylindrical waveguides partially filled by plasmas

    Science.gov (United States)

    Girka, Igor O.; Pavlenko, Ivan V.; Thumm, Manfred

    2018-05-01

    Azimuthal surface waves are electromagnetic eigenwaves of cylindrical plasma-dielectric waveguides which propagate azimuthally nearby the plasma-dielectric interface across an axial external stationary magnetic field. Their eigenfrequency in particular can belong to the electron cyclotron frequency range. Excitation of azimuthal surface waves by rotating relativistic electron flows was studied in detail recently in the case of the zeroth radial mode for which the waves' radial phase change within the layer where the electrons gyrate is small. In this case, just the plasma parameters cause the main influence on the waves' dispersion properties. In the case of the first and higher radial modes, the wave eigenfrequency is higher and the wavelength is shorter than in the case of the zeroth radial mode. This gain being of interest for practical applications can be achieved without any change in the device design. The possibility of effective excitation of the higher order radial modes of azimuthal surface waves is demonstrated here. Getting shorter wavelengths of the excited waves in the case of higher radial modes is shown to be accompanied by decreasing growth rates of the waves. The results obtained here are of interest for developing new sources of electromagnetic radiation, in nano-physics and in medical physics.

  17. Neural dynamics during repetitive visual stimulation

    Science.gov (United States)

    Tsoneva, Tsvetomira; Garcia-Molina, Gary; Desain, Peter

    2015-12-01

    Objective. Steady-state visual evoked potentials (SSVEPs), the brain responses to repetitive visual stimulation (RVS), are widely utilized in neuroscience. Their high signal-to-noise ratio and ability to entrain oscillatory brain activity are beneficial for their applications in brain-computer interfaces, investigation of neural processes underlying brain rhythmic activity (steady-state topography) and probing the causal role of brain rhythms in cognition and emotion. This paper aims at analyzing the space and time EEG dynamics in response to RVS at the frequency of stimulation and ongoing rhythms in the delta, theta, alpha, beta, and gamma bands. Approach.We used electroencephalography (EEG) to study the oscillatory brain dynamics during RVS at 10 frequencies in the gamma band (40-60 Hz). We collected an extensive EEG data set from 32 participants and analyzed the RVS evoked and induced responses in the time-frequency domain. Main results. Stable SSVEP over parieto-occipital sites was observed at each of the fundamental frequencies and their harmonics and sub-harmonics. Both the strength and the spatial propagation of the SSVEP response seem sensitive to stimulus frequency. The SSVEP was more localized around the parieto-occipital sites for higher frequencies (>54 Hz) and spread to fronto-central locations for lower frequencies. We observed a strong negative correlation between stimulation frequency and relative power change at that frequency, the first harmonic and the sub-harmonic components over occipital sites. Interestingly, over parietal sites for sub-harmonics a positive correlation of relative power change and stimulation frequency was found. A number of distinct patterns in delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz) and beta (15-30 Hz) bands were also observed. The transient response, from 0 to about 300 ms after stimulation onset, was accompanied by increase in delta and theta power over fronto-central and occipital sites, which returned to baseline

  18. Challenges in comparing the acute cognitive outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) vs. electroconvulsive therapy (ECT) in major depression: A systematic review.

    Science.gov (United States)

    Kedzior, Karina Karolina; Schuchinsky, Maria; Gerkensmeier, Imke; Loo, Colleen

    2017-08-01

    The present study aimed to systematically compare the cognitive outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) and electroconvulsive therapy (ECT) in head-to-head studies with major depression (MDD) patients. A systematic literature search identified six studies with 219 MDD patients that were too heterogeneous to reliably detect meaningful differences in acute cognitive outcomes after ECT vs. HF-rTMS. Cognitive effects of brain stimulation vary depending on the timeframe and methods of assessment, stimulation parameters, and maintenance treatment. Thus, acute and longer-term differences in cognitive outcomes both need to be investigated at precisely defined timeframes and with similar instruments assessing comparable functions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Warfarin maintenance dose in older patients: higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry.

    Science.gov (United States)

    Garwood, Candice L; Clemente, Jennifer L; Ibe, George N; Kandula, Vijay A; Curtis, Kristy D; Whittaker, Peter

    2010-06-15

    Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed. Our chart review examined 170 patients of African ancestry and 49 patients of European ancestry cared for in our anticoagulation clinic. We calculated the average weekly dose required for each stable, anticoagulated patient to maintain an international normalized ratio of 2.0 to 3.0, determined dose averages for groups 80 years of age and plotted dose as a function of age. The maintenance dose in patients of African ancestry decreased with age (PAfrican ancestry required higher average weekly doses than patients of European ancestry: 33% higher in the 70- to 79-year-old group (38.2+/-1.9 vs. 28.8+/-1.7 mg; P=0.006) and 52% in the >80-year-old group (33.2+/-1.7 vs. 21.8+/-3.8 mg; P=0.011). Therefore, 43% of older patients of African ancestry required daily doses >5mg and hence would have been under-dosed using current starting-dose guidelines. The dose frequency distribution was wider for older patients of African ancestry compared to those of European ancestry (PAfrican ancestry indicate that strategies for initiating warfarin therapy based on studies of patients of European ancestry could result in insufficient anticoagulation and thereby potentially increase their thromboembolism risk. Copyright 2010 Elsevier Inc. All rights reserved.

  20. Effectiveness of fixed-site high-frequency transcutaneous electrical nerve stimulation in chronic pain: a large-scale, observational study

    Science.gov (United States)

    Kong, Xuan; Gozani, Shai N

    2018-01-01

    Objective The objective of this study was to assess the effectiveness of fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS) in a real-world chronic pain sample. Background There is a need for nonpharmacological treatment options for chronic pain. FS-TENS improved multisite chronic pain in a previous interventional study. Large observational studies are needed to further characterize its effectiveness. Methods This retrospective observational cohort study examined changes in chronic pain measures following 60 days of FS-TENS use. The study data were obtained from FS-TENS users who uploaded their device utilization and clinical data to an online database. The primary outcome measures were changes in pain intensity and pain interference with sleep, activity, and mood on an 11-point numerical rating scale. Dose–response associations were evaluated by stratifying subjects into low (≤30 days), intermediate (31–56 days), and high (≥57 days) utilization subgroups. FS-TENS effectiveness was quantified by baseline to follow-up group differences and a responder analysis (≥30% improvement in pain intensity or ≥2-point improvement in pain interference domains). Results Utilization and clinical data were collected from 11,900 people using FS-TENS for chronic pain, with 713 device users meeting the inclusion and exclusion criteria. Study subjects were generally older, overweight adults. Subjects reported multisite pain with a mean of 4.8 (standard deviation [SD] 2.5) pain sites. A total of 97.2% of subjects identified low back and/or lower extremity pain, and 72.9% of subjects reported upper body pain. All pain measures exhibited statistically significant group differences from baseline to 60-day follow-up. The largest changes were pain interference with activity (−0.99±2.69 points) and mood (−1.02±2.78 points). A total of 48.7% of subjects exhibited a clinically meaningful reduction in pain interference with activity or mood. This

  1. Effectiveness of theta burst versus high-frequency repetitive transcranial magnetic stimulation in patients with depression (THREE-D): a randomised non-inferiority trial.

    Science.gov (United States)

    Blumberger, Daniel M; Vila-Rodriguez, Fidel; Thorpe, Kevin E; Feffer, Kfir; Noda, Yoshihiro; Giacobbe, Peter; Knyahnytska, Yuliya; Kennedy, Sidney H; Lam, Raymond W; Daskalakis, Zafiris J; Downar, Jonathan

    2018-04-28

    Treatment-resistant major depressive disorder is common; repetitive transcranial magnetic stimulation (rTMS) by use of high-frequency (10 Hz) left-side dorsolateral prefrontal cortex stimulation is an evidence-based treatment for this disorder. Intermittent theta burst stimulation (iTBS) is a newer form of rTMS that can be delivered in 3 min, versus 37·5 min for a standard 10 Hz treatment session. We aimed to establish the clinical effectiveness, safety, and tolerability of iTBS compared with standard 10 Hz rTMS in adults with treatment-resistant depression. In this randomised, multicentre, non-inferiority clinical trial, we recruited patients who were referred to specialty neurostimulation centres based at three Canadian university hospitals (Centre for Addiction and Mental Health and Toronto Western Hospital, Toronto, ON, and University of British Columbia Hospital, Vancouver, BC). Participants were aged 18-65 years, were diagnosed with a current treatment-resistant major depressive episode or could not tolerate at least two antidepressants in the current episode, were receiving stable antidepressant medication doses for at least 4 weeks before baseline, and had an HRSD-17 score of at least 18. Participants were randomly allocated (1:1) to treatment groups (10 Hz rTMS or iTBS) by use of a random permuted block method, with stratification by site and number of adequate trials in which the antidepressants were unsuccessful. Treatment was delivered open-label but investigators and outcome assessors were masked to treatment groups. Participants were treated with 10 Hz rTMS or iTBS to the left dorsolateral prefrontal cortex, administered on 5 days a week for 4-6 weeks. The primary outcome measure was change in 17-item Hamilton Rating Scale for Depression (HRSD-17) score, with a non-inferiority margin of 2·25 points. For the primary outcome measure, we did a per-protocol analysis of all participants who were randomly allocated to groups and who attained the primary

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

    Science.gov (United States)

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

    2016-07-01

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

  3. Reliability of low-frequency auditory stimulation studies associated with technetium-99m hexamethylpropylene amine oxime single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Le Saco, Y.; Turzo, A.; Guias, B.; Morin, P.P. (Centre Hospitalier Universitaire, 29 - Brest (France). Dept. of Nuclear Medicine); Jezequel, J. (Centre Hospitalier Universitaire, 29 - Brest (France). Dept. of Otorhinolaryngology); Robier, A. (Centre Hospitalier Universitaire, 37 - Tours (France). Dept. of Otorhinolaryngology); Baulieu, J.L. (Centre Hospitalier Universitaire, 37 - Tours (France). Dept. of Nuclear Medicine)

    1993-05-01

    Development of auditory stimulation tests associated with single-photon emission tomography (SPET) shows evidence of variations in perfusion related to the stimuli. Three brain SPET examinations with technetium-99m hexamethylpropylene amine oxime were performed on eight right-handed adults with normal hearing, the first one without stimulation and the other two associated with a 500-Hz/30-dB stimulation of the right ear. Temporal regions of interest covering auditory areas, as well as parietal ones (internal control), were drawn on three successive coronal slices. A cortico-cerebellar index R was calculated, and the variation in activity was defined for each subject using the ratio R[sub poststimulation] - R[sub prestimulation]/R[sub prest]u[sub mulation]. A significant increase in the temporal cortex count occurred in all subjects. This increase was bilateral, except for one subject in whom it was not significant on the right side. This result recurred during the second stimulation study. Overall the response of the left temporal cortex was stronger, although the asymmetry was not significant. The asymmetry repeated itself after each stimulation. The perfursion response is globally reliable in our study. We must ascertainhow sensitive this test is with regard to deaf adults and adults with normal hearing before extending its use to children. (orig.).

  4. Reliability of low-frequency auditory stimulation studies associated with technetium-99m hexamethylpropylene amine oxime single-photon emission tomography

    International Nuclear Information System (INIS)

    Le Saco, Y.; Turzo, A.; Guias, B.; Morin, P.P.; Jezequel, J.; Robier, A.; Baulieu, J.L.

    1993-01-01

    Development of auditory stimulation tests associated with single-photon emission tomography (SPET) shows evidence of variations in perfusion related to the stimuli. Three brain SPET examinations with technetium-99m hexamethylpropylene amine oxime were performed on eight right-handed adults with normal hearing, the first one without stimulation and the other two associated with a 500-Hz/30-dB stimulation of the right ear. Temporal regions of interest covering auditory areas, as well as parietal ones (internal control), were drawn on three successive coronal slices. A cortico-cerebellar index R was calculated, and the variation in activity was defined for each subject using the ratio R poststimulation - R prestimulation /R prest u mulation . A significant increase in the temporal cortex count occurred in all subjects. This increase was bilateral, except for one subject in whom it was not significant on the right side. This result recurred during the second stimulation study. Overall the response of the left temporal cortex was stronger, although the asymmetry was not significant. The asymmetry repeated itself after each stimulation. The perfursion response is globally reliable in our study. We must ascertainhow sensitive this test is with regard to deaf adults and adults with normal hearing before extending its use to children. (orig.)

  5. Quadri-Pulse Theta Burst Stimulation using Ultra-High Frequency Bursts - A New Protocol to Induce Changes in Cortico-Spinal Excitability in Human Motor Cortex

    DEFF Research Database (Denmark)

    Jung, Nikolai H; Gleich, Bernhard; Gattinger, Norbert

    2016-01-01

    Patterned transcranial magnetic stimulation (TMS) such as theta burst stimulation (TBS) or quadri-pulse stimulation (QPS) can induce changes in cortico-spinal excitability, commonly referred to as long-term potentiation (LTP)-like and long-term depression (LTD)-like effects in human motor cortex (M...... of sinusoidal TMS pulses elicited either a posterior-anterior (PA) or anterior-posterior (AP) directed current in M1. Motor evoked potentials (MEPs) were recorded before and after qTBS to probe changes in cortico-spinal excitability. PA-qTBS at 666 Hz caused a decrease in PA-MEP amplitudes, whereas AP...... in cortico-spinal excitability. Induced current direction in the brain appears to be relevant when qTBS targets I-wave periodicity, corroborating that high-fidelity spike timing mechanisms are critical for inducing bi-directional plasticity in human M1....

  6. Real-time monitoring of extracellular l-glutamate levels released by high-frequency stimulation at region CA1 of hippocampal slices with a glass capillary-based l-glutamate sensor

    Directory of Open Access Journals (Sweden)

    Yuki Ikegami

    2014-12-01

    Full Text Available Real-time monitoring of l-glutamate released by high-frequency stimulation in region CA1 of mouse hippocampal slices was performed with a glass capillary-based sensor, in combination with the recoding of excitatory postsynaptic potentials (fEPSPs. A method for extracting l-glutamate currents from the recorded ones was described and applied for determining the level of extracellular l-glutamate released by 100 Hz stimulation. Recording of an l-glutamate current with a current sampling interval of 1 Hz was found to be useful for acquiring a Faradaic current that reflects l-glutamate level released by the high-frequency stimulation of 7 trains, each 20 stimuli at 100 Hz and inter-train interval of 3 s. The l-glutamate level was obtained as 15 ± 6 μM (n = 8 for the persistent enhancement of fEPSPs, i.e., the induction of long-term potentiation (LTP, and 3 ± 1 μM (n = 5 for the case of no LTP induction. Based on these observations, the level of the extracellular l-glutamate was shown to play a crucial role in the induction of LTP.

  7. Music acupuncture stimulation method.

    Science.gov (United States)

    Brătilă, F; Moldovan, C

    2007-01-01

    Harmonic Medicine is the model using the theory that the body rhythms synchronize to an outer rhythm applied for therapeutic purpose, can restores the energy balance in acupuncture channels and organs and the condition of well-being. The purpose of this scientific work was to demonstrate the role played by harmonic sounds in the stimulation of the Lung (LU) Meridian (Shoutaiyin Feijing) and of the Kidney (KI) Meridian (Zushaoyin Shenjing). It was used an original method that included: measurement and electronic sound stimulation of the Meridian Entry Point, measurement of Meridian Exit Point, computer data processing, bio feed-back adjustment of the music stimulation parameters. After data processing, it was found that the sound stimulation of the Lung Meridian Frequency is optimal between 122 Hz and 128 Hz, with an average of 124 Hz (87% of the subjects) and for Kidney Meridian from 118 Hz to 121 Hz, with an average of 120 Hz (67% of the subjects). The acupuncture stimulation was more intense for female subjects (> 7%) than for the male ones. We preliminarily consider that an informational resonance phenomenon can be developed between the acupuncture music stimulation frequency and the cellular dipole frequency, being a really "resonant frequency signature" of an acupoint. The harmonic generation and the electronic excitation or low-excitation status of an acupuncture point may be considered as a resonance mechanism. By this kind of acupunctural stimulation, a symphony may act and play a healer role.

  8. Lack of evidence of HPV etiology of prostate cancer following radical surgery and higher frequency of the Arg/Pro genotype in turkish men with prostate cancer

    Directory of Open Access Journals (Sweden)

    Merve Aydin

    Full Text Available ABSTRACT Objectives The aim of this study was to assess the possible role of HPV in the development of prostate cancer (PCa and investigate the distribution of the p53 codon 72 polymorphism in PCa in a Turkish population. Materials and methods A total of 96 tissues, which had been obtained using a radical surgery method, formalin-fixed and parafin-embedded, were used in this study. The study group consisted of 60 PCa tissues (open radical prostatectomy and the control group contained 36 benign prostatic hyperplasia tissues (BPH (transvesical open prostatectomy. The presence of HPV and the p53 codon 72 polymorphism was investigated in both groups using real-time PCR and pyrosequencing. Results The results of the real-time PCR showed no HPV DNA in any of the 36 BPH tissue samples. HPV-DNA was positive in only 1 of the 60 PCa samples (1.7%. The HPV type of this sample was identified as HPV-57. The distribution of the three genotypes, Arg/Arg, Arg/Pro and Pro/Pro was found to be 45.6, 45.6, and 8.8% in the PCa group and 57.1%, 34.3% and 8.6% in the control group, respectively. Compared with the control group, patients with PCa had a higher frequency of the Arg/Pro genotype and Proline allele (odds ratio (OR=1.67, 95% confidence interval (CI=0.68-4.09, p=0.044; OR=1.13, 95% CI=0.76-1.68, p=0.021, respectively. Conclusions The results of the study do not support the hyphothesis that prostate cancer is associated with HPV infection but indicated that Proline allele can be a risk factor in the development of PCa in the Turkish population.

  9. Endometrial Scratch Injury Induces Higher Pregnancy Rate for Women With Unexplained Infertility Undergoing IUI With Ovarian Stimulation: A Randomized Controlled Trial.

    Science.gov (United States)

    Maged, Ahmed M; Al-Inany, Hesham; Salama, Khaled M; Souidan, Ibrahim I; Abo Ragab, Hesham M; Elnassery, Noura

    2016-02-01

    To explore the impact of endometrial scratch injury (ESI) on intrauterine insemination (IUI) success. One hundred and fifty four infertile women received 100 mg of oral clomiphene citrate for 5 days starting on day 3 of the menstrual cycle. Patients were randomized to 2 equal groups: Group C received IUI without ESI and group S had ESI. Successful pregnancy was confirmed by ultrasound. 13, 21, and 10 women got pregnant after the first, second, and third IUI trials, respectively, with 28.6% cumulative pregnancy rate (PR). The cumulative PR was significantly higher in group S (39%) compared to group C (18.2%). The PR in group S was significantly higher compared to that in group C at the second and third trials. The PR was significantly higher in group S at the second trial compared to that reported in the same group at the first trial but nonsignificantly higher compared to that reported during the third trial, while in group C, the difference was nonsignificant. Eight pregnant women had first trimester abortion with 18.2% total abortion rate with nonsignificant difference between studied groups. The ESI significantly improves the outcome of IUI in women with unexplained infertility especially when conducted 1 month prior to IUI. © The Author(s) 2015.

  10. Evidence for the distortion product frequency place as a source of distribution product otoacoustic emission (DPOAE) fine structure in humans : I. Fine structure and higher-order DPOAE as a function of the frequency ratio f2/f1

    NARCIS (Netherlands)

    Mauermann, M; Uppenkamp, S; van Hengel, P.W.J.; Kollmeier, B

    1999-01-01

    Critical experiments were performed in order to validate the two-source hypothesis of distortion product otoacoustic emissions (DPOAE) generation. Measurements of the spectral fine structure of DPOAE in response to stimulation with two sinusoids have been:performed with normal-hearing subjects. The

  11. Psychophysical Evaluation of Subdermal Electrical Stimulation in Relation to Prosthesis Sensory Feedback.

    Science.gov (United States)

    Geng, Bo; Dong, Jian; Jensen, Winnie; Dosen, Strahinja; Farina, Dario; Kamavuako, Ernest Nlandu

    2018-03-01

    This paper evaluated the psychophysical properties of subdermal electrical stimulation to investigate its feasibility in providing sensory feedback for limb prostheses. The detection threshold (DT), pain threshold (PT), just noticeable difference (JND), as well as the elicited sensation quality, comfort, intensity, and location were assessed in 16 healthy volunteers during stimulation of the ventral and dorsal forearm with subdermal electrodes. Moreover, the results were compared with those obtained from transcutaneous electrical stimulation. Despite a lower DT and PT, subdermal stimulation attained a greater relative dynamic range (i.e., PT/DT) and significantly smaller JNDs for stimulation amplitude. Muscle twitches and movements were more commonly elicited by surface stimulation, especially at the higher stimulation frequencies, whereas the pinprick sensation was more often reported with subdermal stimulation. Less comfort was perceived in subdermal stimulation of the ventral forearm at the highest tested stimulation frequency of 100 Hz. In summary, subdermal electrical stimulation was demonstrated to be able to produce similar sensation quality as transcutaneous stimulation and outperformed the latter in terms of energy efficiency and sensitivity. These results suggest that stimulation through implantable subdermal electrodes may lead to an efficient and compact sensory feedback system for substituting the lost sense in amputees.

  12. Higher Physiotherapy Frequency Is Associated with Shorter Length of Stay and Greater Functional Recovery in Hospitalized Frail Older Adults: A Retrospective Observational Study.

    Science.gov (United States)

    Hartley, P; Adamson, J; Cunningham, C; Embleton, G; Romero-Ortuno, R

    2016-01-01

    Extra physiotherapy has been associated with better outcomes in hospitalized patients, but this remains an under-researched area in geriatric medicine wards. We retrospectively studied the association between average physiotherapy frequency and outcomes in hospitalized geriatric patients. High frequency physiotherapy (HFP) was defined as ≥0.5 contacts/day. Of 358 eligible patients, 131 (36.6%) received low, and 227 (63.4%) HFP. Functional improvement (discharge versus admission) in the modified Rankin scale was greater in the HFP group (1.1 versus 0.7 points, Pphysiotherapy frequency and intensity in geriatric wards.

  13. [Transcranial magnetic stimulation and motor cortex stimulation in neuropathic pain].

    Science.gov (United States)

    Mylius, V; Ayache, S S; Teepker, M; Kappus, C; Kolodziej, M; Rosenow, F; Nimsky, C; Oertel, W H; Lefaucheur, J P

    2012-12-01

    Non-invasive and invasive cortical stimulation allows the modulation of therapy-refractory neuropathic pain. High-frequency repetitive transcranial magnetic stimulation (rTMS) of the contralateral motor cortex yields therapeutic effects at short-term and predicts the benefits of epidural motor cortex stimulation (MCS). The present article summarizes the findings on application, mechanisms and therapeutic effects of cortical stimulation in neuropathic pain.

  14. Higher physiotherapy frequency is associated with shorter length of stay and greater functional recovery in hospitalized frail older adults: a retrospective observational study

    OpenAIRE

    Hartley, Peter; Adamson, Jennifer; Cunningham, Carol; Embleton, Georgina; Romero-Ortuno, Roman

    2016-01-01

    Extra physiotherapy has been associated with better outcomes in hospitalized patients, but this remains an under-researched area in geriatric medicine wards. We retrospectively studied the association between average physiotherapy frequency and outcomes in hospitalized geriatric patients. High frequency physiotherapy (HFP) was defined as ≥0.5 contacts/day. Of 358 eligible patients, 131 (36.6%) received low, and 227 (63.4%) HFP. Functional improvement (discharge versus admission) in the modifi...

  15. ITER Plasma at Ion Cyclotron Frequency Domain: The Fusion Alpha Particles Diagnostics Based on the Stimulated Raman Scattering of Fast Magnetosonic Wave off High Harmonic Ion Bernstein Modes

    Science.gov (United States)

    Stefan, V. Alexander

    2014-10-01

    A novel method for alpha particle diagnostics is proposed. The theory of stimulated Raman scattering, SRS, of the fast wave and ion Bernstein mode, IBM, turbulence in multi-ion species plasmas, (Stefan University Press, La Jolla, CA, 2008). is utilized for the diagnostics of fast ions, (4)He (+2), in ITER plasmas. Nonlinear Landau damping of the IBM on fast ions near the plasma edge leads to the space-time changes in the turbulence level, (inverse alpha particle channeling). The space-time monitoring of the IBM turbulence via the SRS techniques may prove efficient for the real time study of the fast ion velocity distribution function, spatial distribution, and transport. Supported by Nikola Tesla Labs., La Jolla, CA 92037.

  16. Adjunct High Frequency Transcutaneous Electric Stimulation (TENS) for Postoperative Pain Management during Weaning from Epidural Analgesia Following Colon Surgery: Results from a Controlled Pilot Study.

    Science.gov (United States)

    Bjerså, Kristofer; Jildenstaal, Pether; Jakobsson, Jan; Egardt, Madelene; Fagevik Olsén, Monika

    2015-12-01

    The potential benefit of nonpharmacological adjunctive therapy is not well-studied following major abdominal surgery. The aim of the present study was to investigate transcutaneous electrical nerve stimulation (TENS) as a complementary nonpharmacological analgesia intervention during weaning from epidural analgesia (EDA) after open lower abdominal surgery. Patients were randomized to TENS and sham TENS during weaning from EDA. The effects on pain at rest, following short walk, and after deep breath were assessed by visual analog scale (VAS) grading. Number of patients assessed was lower than calculated because of change in clinical routine. Pain scores overall were low. A trend of lower pain scores was observed in the active TENS group of patients; a statistical significance between the groups was found for the pain lying prone in bed (p TENS use in postoperative pain management during weaning from EDA after open colon surgery. Further studies are warranted in order to verify the potential beneficial effects from TENS during weaning from EDA after open, lower abdominal surgery. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  17. Sub-paresthesia spinal cord stimulation reverses thermal hyperalgesia and modulates low frequency EEG in a rat model of neuropathic pain.

    Science.gov (United States)

    Koyama, Suguru; Xia, Jimmy; Leblanc, Brian W; Gu, Jianwen Wendy; Saab, Carl Y

    2018-05-08

    Paresthesia, a common feature of epidural spinal cord stimulation (SCS) for pain management, presents a challenge to the double-blind study design. Although sub-paresthesia SCS has been shown to be effective in alleviating pain, empirical criteria for sub-paresthesia SCS have not been established and its basic mechanisms of action at supraspinal levels are unknown. We tested our hypothesis that sub-paresthesia SCS attenuates behavioral signs of neuropathic pain in a rat model, and modulates pain-related theta (4-8 Hz) power of the electroencephalogram (EEG), a previously validated correlate of spontaneous pain in rodent models. Results show that sub-paresthesia SCS attenuates thermal hyperalgesia and power amplitude in the 3-4 Hz range, consistent with clinical data showing significant yet modest analgesic effects of sub-paresthesia SCS in humans. Therefore, we present evidence for anti-nociceptive effects of sub-paresthesia SCS in a rat model of neuropathic pain and further validate EEG theta power as a reliable 'biosignature' of spontaneous pain.

  18. Neuromuscular electrical stimulation improves exercise tolerance in chronic obstructive pulmonary disease patients with better preserved fat-free mass

    Directory of Open Access Journals (Sweden)

    Lara Maris Nápolis

    2011-01-01

    Full Text Available BACKGROUND: High-frequency neuromuscular electrical stimulation increases exercise tolerance in patients with advanced chronic obstructive pulmonary disease (COPD patients. However, it is conceivable that its benefits are more prominent in patients with better-preserved peripheral muscle function and structure. OBJECTIVE: To investigate the effects of high-frequency neuromuscular electrical stimulation in COPD patients with better-preserved peripheral muscle function. Design: Prospective and cross-over study. METHODS: Thirty COPD patients were randomly assigned to either home-based, high-frequency neuromuscular electrical stimulation or sham stimulation for six weeks. The training intensity was adjusted according to each subject's tolerance. Fat-free mass, isometric strength, six-minute walking distance and time to exercise intolerance (Tlim were assessed. RESULTS: Thirteen (46.4% patients responded to high-frequency neuromuscular electrical stimulation; that is, they had a post/pre Δ Tlim >10% after stimulation (unimproved after sham stimulation. Responders had a higher baseline fat-free mass and six-minute walking distance than their seventeen (53.6% non-responding counterparts. Responders trained at higher stimulation intensities; their mean amplitude of stimulation during training was significantly related to their fat-free mass (r = 0.65; p<0.01. Logistic regression revealed that fat-free mass was the single independent predictor of Tlim improvement (odds ratio [95% CI] = 1.15 [1.04-1.26]; p<0.05. CONCLUSIONS: We conclude that high-frequency neuromuscular electrical stimulation improved the exercise capacity of COPD patients with better-preserved fat-free mass because they tolerated higher training stimulus levels. These data suggest that early training with high-frequency neuromuscular electrical stimulation before tissue wasting begins might enhance exercise tolerance in patients with less advanced COPD.

  19. Acute effects of high-frequency microfocal vibratory stimulation on the H reflex of the soleus muscle. A double-blind study in healthy subjects.

    Science.gov (United States)

    Alfonsi, Enrico; Paone, Paolo; Tassorelli, Cristina; De Icco, Roberto; Moglia, Arrigo; Alvisi, Elena; Marchetta, Lucky; Fresia, Mauro; Montini, Alessandra; Calabrese, Marzia; Versiglia, Vittorio; Sandrini, Giorgio

    2015-01-01

    This study in healthy subjects examined the effects of a system delivering focal microvibrations at high frequency (Equistasi®) on tonic vibration stimulus (TVS)-induced inhibition of the soleus muscle H reflex. Highfrequency microvibrations significantly increased the inhibitory effect of TVS on the H reflex for up to three minutes. Moreover, Equistasi® also significantly reduced alpha-motoneuron excitability, as indicated by the changes in the ratio between the maximumamplitude H reflex (Hmax reflex) and the maximumamplitude muscle response (Mmax response); this effect was due to reduction of the amplitude of the H reflex because the amplitude of muscle response remained unchanged. The present findings indicate that Equistasi® has a modulatory effect on proprioceptive reflex circuits. Therefore, Equistasi® might interfere with some mechanisms involved in both physiological and pathophysiological control of movement and of posture.

  20. The Impact of Accelerated Right Prefrontal High-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS on Cue-Reactivity: An fMRI Study on Craving in Recently Detoxified Alcohol-Dependent Patients.

    Directory of Open Access Journals (Sweden)

    Sarah C Herremans

    Full Text Available In alcohol-dependent patients craving is a difficult-to-treat phenomenon. It has been suggested that high-frequency (HF repetitive transcranial magnetic stimulation (rTMS may have beneficial effects. However, exactly how this application exerts its effect on the underlying craving neurocircuit is currently unclear. In an effort to induce alcohol craving and to maximize detection of HF-rTMS effects to cue-induced alcohol craving, patients were exposed to a block and event-related alcohol cue-reactivity paradigm while being scanned with fMRI. Hence, we assessed the effect of right dorsolateral prefrontal cortex (DLPFC stimulation on cue-induced and general alcohol craving, and the related craving neurocircuit. Twenty-six recently detoxified alcohol-dependent patients were included. First, we evaluated the impact of one sham-controlled stimulation session. Second, we examined the effect of accelerated right DLPFC HF-rTMS treatment: here patients received 15 sessions in an open label accelerated design, spread over 4 consecutive days. General craving significantly decreased after 15 active HF-rTMS sessions. However, cue-induced alcohol craving was not altered. Our brain imaging results did not show that the cue-exposure affected the underlying craving neurocircuit after both one and fifteen active HF-rTMS sessions. Yet, brain activation changes after one and 15 HF-rTMS sessions, respectively, were observed in regions associated with the extended reward system and the default mode network, but only during the presentation of the event-related paradigm. Our findings indicate that accelerated HF-rTMS applied to the right DLPFC does not manifestly affect the craving neurocircuit during an alcohol-related cue-exposure, but instead it may influence the attentional network.

  1. Nanosecond laser pulse stimulation of spiral ganglion neurons and model cells.

    Science.gov (United States)

    Rettenmaier, Alexander; Lenarz, Thomas; Reuter, Günter

    2014-04-01

    Optical stimulation of the inner ear has recently attracted attention, suggesting a higher frequency resolution compared to electrical cochlear implants due to its high spatial stimulation selectivity. Although the feasibility of the effect is shown in multiple in vivo experiments, the stimulation mechanism remains open to discussion. Here we investigate in single-cell measurements the reaction of spiral ganglion neurons and model cells to irradiation with a nanosecond-pulsed laser beam over a broad wavelength range from 420 nm up to 1950 nm using the patch clamp technique. Cell reactions were wavelength- and pulse-energy-dependent but too small to elicit action potentials in the investigated spiral ganglion neurons. As the applied radiant exposure was much higher than the reported threshold for in vivo experiments in the same laser regime, we conclude that in a stimulation paradigm with nanosecond-pulses, direct neuronal stimulation is not the main cause of optical cochlea stimulation.

  2. Stimulated Thomson scattering

    International Nuclear Information System (INIS)

    Spencer, R.L.

    1979-03-01

    The theory of stimulated Thomson scattering is investigated both quantum mechanically and classically. Two monochromatic electromagnetic waves of like polarization travelling in opposite directions are allowed to interact for a time tau with the electrons in a collisionless plasma. The electromagnetic waves have frequencies well above the plasma frequency, and their difference frequency is allowed to range upward from the plasma frequency. With the difference frequency well above the plasma frequency, the rate at which energy is transferred from one wave to the other is calculated quantum mechanically, classically from a fluid theory, and classically from an independent electron theory. The rate is calculated in both the homogeneously broadened limit, and in the inhomogeneously broadened limit

  3. Stimulation of neural differentiation in human bone marrow mesenchymal stem cells by extremely low-frequency electromagnetic fields incorporated with MNPs.

    Science.gov (United States)

    Choi, Yun-Kyong; Lee, Dong Heon; Seo, Young-Kwon; Jung, Hyun; Park, Jung-Keug; Cho, Hyunjin

    2014-10-01

    Human bone marrow-derived mesenchymal stem cells (hBM-MSCs) have been investigated as a new cell-therapeutic solution due to their capacity that could differentiate into neural-like cells. Extremely low-frequency electromagnetic fields (ELF-EMFs) therapy has emerged as a novel technique, using mechanical stimulus to differentiate hBM-MSCs and significantly enhance neuronal differentiation to affect cellular and molecular reactions. Magnetic iron oxide (Fe3O4) nanoparticles (MNPs) have recently achieved widespread use for biomedical applications and polyethylene glycol (PEG)-labeled nanoparticles are used to increase their circulation time, aqueous solubility, biocompatibility, and nonspecific cellular uptake as well as to decrease immunogenicity. Many studies have used MNP-labeled cells for differentiation, but there have been no reports of MNP-labeled neural differentiation combined with EMFs. In this study, synthesized PEG-phospholipid encapsulated magnetite (Fe3O4) nanoparticles are used on hBM-MSCs to improve their intracellular uptake. The PEGylated nanoparticles were exposed to the cells under 50 Hz of EMFs to improve neural differentiation. First, we measured cell viability and intracellular iron content in hBM-MSCs after treatment with MNPs. Analysis was conducted by RT-PCR, and immunohistological analysis using neural cell type-specific genes and antibodies after exposure to 50 Hz electromagnetic fields. These results suggest that electromagnetic fields enhance neural differentiation in hBM-MSCs incorporated with MNPs and would be an effective method for differentiating neural cells.

  4. Comparing the force ripple during asynchronous and conventional stimulation.

    Science.gov (United States)

    Downey, Ryan J; Tate, Mark; Kawai, Hiroyuki; Dixon, Warren E

    2014-10-01

    Asynchronous stimulation has been shown to reduce fatigue during electrical stimulation; however, it may also exhibit a force ripple. We quantified the ripple during asynchronous and conventional single-channel transcutaneous stimulation across a range of stimulation frequencies. The ripple was measured during 5 asynchronous stimulation protocols, 2 conventional stimulation protocols, and 3 volitional contractions in 12 healthy individuals. Conventional 40 Hz and asynchronous 16 Hz stimulation were found to induce contractions that were as smooth as volitional contractions. Asynchronous 8, 10, and 12 Hz stimulation induced contractions with significant ripple. Lower stimulation frequencies can reduce fatigue; however, they may also lead to increased ripple. Future efforts should study the relationship between force ripple and the smoothness of the evoked movements in addition to the relationship between stimulation frequency and NMES-induced fatigue to elucidate an optimal stimulation frequency for asynchronous stimulation. © 2014 Wiley Periodicals, Inc.

  5. High frequency oscillations in brain hemodynamic response

    Science.gov (United States)

    Akin, Ata; Bolay, Hayrunnisa

    2007-07-01

    Tight autoregulation of vessel tone guarantees proper delivery of nutrients to the tissues. This regulation is maintained at a more delicate level in the brain since any decrease in the supply of glucose and oxygen to neuronal tissues might lead to unrecoverable injury. Functional near infrared spectroscopy has been proposed as a new tool to monitor the cerebrovascular response during cognitive activity. We have observed that during a Stroop task three distinct oscillatory patterns govern the control of the cerebrovascular reactivity: very low frequency (0.02-0.05 Hz), low frequency (0.08-0.12 Hz) and high frequency (0.12-0.18 Hz). High frequency oscillations have been shown to be related to stress level of the subjects. Our findings indicate that as the stress level is increased so does the energy of the high frequency component indicating a higher stimulation from the autonomic nervous system.

  6. Higher frequency of cagA EPIYA-C Phosphorylation Sites in H. pylori strains from first-degree relatives of gastric cancer patients

    Directory of Open Access Journals (Sweden)

    Queiroz Dulciene MM

    2012-08-01

    Full Text Available Abstract Background To evaluate the prevalence of more virulent H. pylori genotypes in relatives of gastric cancer patients and in patients without family histories of gastric cancer. Methods We evaluated prospectively the prevalence of the infection by more virulent H. pylori strains in 60 relatives of gastric cancer patients comparing the results with those obtained from 49 patients without family histories of gastric cancer. H. pylori status was determined by the urease test, histology and presence of H. pylori ureA. The cytotoxin associated gene (cagA, the cagA-EPIYA and vacuolating cytotoxin gene (vacA were typed by PCR and the cagA EPIYA typing was confirmed by sequencing. Results The gastric cancer relatives were significant and independently more frequently colonized by H. pylori strains with higher numbers of CagA-EPIYA-C segments (OR = 4.23, 95%CI = 1.53–11.69 and with the most virulent s1m1 vacA genotype (OR = 2.80, 95%CI = 1.04–7.51. Higher numbers of EPIYA-C segments were associated with increased gastric corpus inflammation, foveolar hyperplasia and atrophy. Infection by s1m1 vacA genotype was associated with increased antral and corpus gastritis. Conclusions We demonstrated that relatives of gastric cancer patients are more frequently colonized by the most virulent H. pylori cagA and vacA genotypes, which may contribute to increase the risk of gastric cancer.

  7. Frequency-dependence of the slow force response.

    Science.gov (United States)

    von Lewinski, Dirk; Zhu, Danan; Khafaga, Mounir; Kockskamper, Jens; Maier, Lars S; Hasenfuss, Gerd; Pieske, Burkert

    2008-05-01

    Stretch induces biphasic inotropic effects in mammalian myocardium. A delayed component (slow force response, SFR) has been demonstrated in various species, however, experimental conditions varied and the underlying mechanisms are controversial. The physiological relevance of the SFR is poorly understood. Experiments were performed in ventricular muscle strips from failing human hearts and non-failing rabbit hearts. Upon stretch, twitch force was assessed at basal conditions (1 Hz, 37 degrees C) and after changing stimulation frequency with and without blockade of the Na+/H+-exchanger-1 (NHE1) or reverse-mode Na+/Ca2+-exchange (NCX). Action potential duration (APD) was assessed using floating electrodes. Low stimulation rates (0.2 Hz) potentiated and higher stimulation rates (2 and 3 Hz) reduced the SFR. The extent of SFR inhibition by NHE1 or NCX inhibition was not affected by stimulation rate. APD decreased at 0.2 Hz but was not altered at higher stimulation rates. The data demonstrate frequency-dependence of the SFR with greater positive inotropic effects at lower stimulation rates. Subcellular mechanisms underlying the SFR are not fundamentally affected by stimulation rate. The SFR may have more pronounced physiological effects at lower heart rates.

  8. The positive effects of high-frequency right dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation on memory, correlated with increases in brain metabolites detected by proton magnetic resonance spectroscopy in recently detoxified alcohol-dependent patients.

    Science.gov (United States)

    Qiao, Jun; Jin, Guixing; Lei, Licun; Wang, Lan; Du, Yaqiang; Wang, Xueyi

    2016-01-01

    To explore the effect of right dorsolateral prefrontal cortex (DLPFC) repetitive transcranial magnetic stimulation (rTMS) on memory, and its correlation with levels of hippocampal brain metabolites detected by proton magnetic resonance spectroscopy ( 1 H-MRS) in recently detoxified alcohol-dependent patients. In this randomized, double-blind sham-controlled trial, alcohol-dependent patients were enrolled and randomized into two groups: the experimental group (rTMS, 10 Hz, on right DLPFC, 20 sessions) and the control group (sham stimulation). Memory function was assessed using Hopkins Verbal Learning Test-Revised (HVLT-R) and Brief Visuospatial Memory Test-Revised (BVMT-R) before and after treatment. 1 H-MRS was used to detect the levels of N -acetyl aspartic acid (NAA), choline (Cho), and creatine (Cr) in bilateral hippocampi before and after treatment. Thirty-eight patients (18 in the experimental group and 20 in the control group) were included in the analyses. The experimental group showed significantly greater changes in HVLT-R, BVMT-R, NAA/Cr, and Cho/Cr after rTMS from baseline than the control group. The percentage change in BVMT-R and HVLT-R correlated with the percentage change in NAA/Cr and Cho/Cr in the right brain. High-frequency right DLPFC rTMS was associated with improvement in memory dysfunction, which is correlated with levels of hippocampal brain metabolites detected by 1 H-MRS in recently detoxified alcohol-dependent patients.

  9. High-Frequency Stimulation of the Subthalamic Nucleus Activates Motor Cortex Pyramidal Tract Neurons by a Process Involving Local Glutamate, GABA and Dopamine Receptors in Hemi-Parkinsonian Rats.

    Science.gov (United States)

    Chuang, Chi-Fen; Wu, Chen-Wei; Weng, Ying; Hu, Pei-San; Yeh, Shin-Rung; Chang, Yen-Chung

    2018-04-30

    Deep brain stimulation (DBS) is widely used to treat advanced Parkinson’s disease (PD). Here, we investigated how DBS applied on the subthalamic nucleus (STN) influenced the neural activity in the motor cortex. Rats, which had the midbrain dopaminergic neurons partially depleted unilaterally, called the hemi-Parkinsonian rats, were used as a study model. c-Fos expression in the neurons was used as an indicator of neural activity. Application of high-frequency stimulation (HFS) upon the STN was used to mimic the DBS treatment. The motor cortices in the two hemispheres of hemi-Parkinsonian rats were found to contain unequal densities of c-Fos-positive (Fos+) cells, and STN-HFS rectified this bilateral imbalance. In addition, STN-HFS led to the intense c-Fos expression in a group of motor cortical neurons which exhibited biochemical and anatomical characteristics resembling those of the pyramidal tract (PT) neurons sending efferent projections to the STN. The number of PT neurons expressing high levels of c-Fos was significantly reduced by local application of the antagonists of non-N-methyl-D-aspartate (non-NMDA) glutamate receptors, gammaaminobutyric acid A (GABAA) receptors and dopamine receptors in the upper layers of the motor cortex. The results indicate that the coincident activations of synapses and dopamine receptors in the motor cortex during STN-HFS trigger the intense expression of c-Fos of the PT neurons. The implications of the results on the cellular mechanism underlying the therapeutic effects of STN-DBS on the movement disorders of PD are also discussed.

  10. The positive effects of high-frequency right dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation on memory, correlated with increases in brain metabolites detected by proton magnetic resonance spectroscopy in recently detoxified alcohol-dependent patients

    Directory of Open Access Journals (Sweden)

    Qiao J

    2016-09-01

    Full Text Available Jun Qiao,1,2 Guixing Jin,1,2 Licun Lei,3 Lan Wang,1,2 Yaqiang Du,3 Xueyi Wang1,2 1Institute of Mental Health, The First Hospital of Hebei Medical University, 2Brain Ageing and Cognitive Neuroscience Laboratory, Hebei Medical University, 3Department of Radiology, The First Hospital of Hebei Medical University, Hebei, People’s Republic of China Objective: To explore the effect of right dorsolateral prefrontal cortex (DLPFC repetitive transcranial magnetic stimulation (rTMS on memory, and its correlation with levels of hippocampal brain metabolites detected by proton magnetic resonance spectroscopy (1H-MRS in recently detoxified alcohol-dependent patients. Materials and methods: In this randomized, double-blind sham-controlled trial, alcohol-dependent patients were enrolled and randomized into two groups: the experimental group (rTMS, 10 Hz, on right DLPFC, 20 sessions and the control group (sham stimulation. Memory function was assessed using Hopkins Verbal Learning Test-Revised (HVLT-R and Brief Visuospatial Memory Test-Revised (BVMT-R before and after treatment. 1H-MRS was used to detect the levels of N-acetyl aspartic acid (NAA, choline (Cho, and creatine (Cr in bilateral hippocampi before and after treatment. Results: Thirty-eight patients (18 in the experimental group and 20 in the control group were included in the analyses. The experimental group showed significantly greater changes in HVLT-R, BVMT-R, NAA/Cr, and Cho/Cr after rTMS from baseline than the control group. The percentage change in BVMT-R and HVLT-R correlated with the percentage change in NAA/Cr and Cho/Cr in the right brain. Conclusion: High-frequency right DLPFC rTMS was associated with improvement in memory dysfunction, which is correlated with levels of hippocampal brain metabolites detected by 1H-MRS in recently detoxified alcohol-dependent patients. Keywords: alcohol dependence, memory, repetitive transcranial magnetic stimulation, MR spectroscopy

  11. Low-Frequency Pulsed Current Versus Kilohertz-Frequency Alternating Current: A Scoping Literature Review.

    Science.gov (United States)

    Vaz, Marco Aurélio; Frasson, Viviane Bortoluzzi

    2018-04-01

    To compare the effectiveness of low-frequency pulsed current versus kilohertz-frequency alternating current in terms of evoked force, discomfort level, current intensity, and muscle fatigability; to discuss the physiological mechanisms of each neuromuscular electrical stimulation type; and to determine if kilohertz-frequency alternating current is better than low-frequency pulsed current for clinical treatment. Articles were obtained from PubMed, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, MEDLINE, and SPORTSDiscus databases using the terms Russian current or kilohertz current or alternating current or pulsed current or Aussie current and torque or discomfort or fatigue or current intensity, and through citation tracking up to July 2017. Two independent reviewers selected studies comparing the use of the 2 neuromuscular electrical stimulation currents. Studies describing maximal current intensity tolerated and the main effects of the 2 different current types on discomfort, muscle force, and fatigability were independently reviewed. Data were systematized according to (1) methodology; (2) electrical current characteristics; and (3) outcomes on discomfort level, evoked force, current intensity, and muscle fatigability. The search revealed 15 articles comparing the 2 current types. Kilohertz-frequency alternated current generated equal or less force, similar discomfort, similar current intensity for maximal tolerated neuromuscular electrical stimulation, and more fatigue compared with low-frequency pulsed current. Similar submaximal levels of evoked force revealed higher discomfort and current intensity for kilohertz-frequency alternated current compared with low-frequency pulsed current. Available evidence does not support the idea that kilohertz-frequency alternated current is better than low-frequency pulsed current for strength training and rehabilitation. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier

  12. Add-on high frequency deep transcranial magnetic stimulation (dTMS) to bilateral prefrontal cortex in depressive episodes of patients with major depressive disorder, bipolar disorder I, and major depressive with alcohol use disorders.

    Science.gov (United States)

    Rapinesi, Chiara; Kotzalidis, Georgios D; Ferracuti, Stefano; Girardi, Nicoletta; Zangen, Abraham; Sani, Gabriele; Raccah, Ruggero N; Girardi, Paolo; Pompili, Maurizio; Del Casale, Antonio

    2018-04-03

    Dorsolateral prefrontal cortex (DLPFC) is critically involved in mood and alcohol use disorders. We aimed to investigate the safety of intervention with add-on bilateral prefrontal high-frequency deep transcranial magnetic stimulation (dTMS) and between-group differences in treatment response in patients with different types of depressive episodes, including major depressive episodes in the course of major depressive disorder (MDD), bipolar disorder, type I (BD-I), and MDD with alcohol use disorder (MDAUD). We conducted a 6-month open-label study, involving 82 patients with DSM-5 Depressive Episode. Of these, 41 had diagnosis of MDD, 20 BD-I, and 21 MDAUD. All patients received standard drug treatment and add-on dTMS over the bilateral DLPFC with left prevalence for four weeks, with five sessions in each week. We rated mood state with the Hamilton Depression Rating Scale (HDRS) at baseline, one-month, and six-month follow-up visits. Mean total HDRS scores dropped from 22.8 (SD = 5.9) at baseline to 10.4 (SD = 3.6) at 1 month, to 10.0 (SD = 4.5) at 6 months, while response/remission were 70.73% (N = 58) and 19.51% (N = 16) at 1 month and 76.83% (N = 63) and 32.93% (27) at 6 months, respectively, with no between-group differences. No patient experienced any side effects. High-frequency DLPFC dTMS was well tolerated and did not significantly differ on improvement of depression in MDD, BD-I, and MDAUD. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Induction of self awareness in dreams through frontal low current stimulation of gamma activity.

    Science.gov (United States)

    Voss, Ursula; Holzmann, Romain; Hobson, Allan; Paulus, Walter; Koppehele-Gossel, Judith; Klimke, Ansgar; Nitsche, Michael A

    2014-06-01

    Recent findings link fronto-temporal gamma electroencephalographic (EEG) activity to conscious awareness in dreams, but a causal relationship has not yet been established. We found that current stimulation in the lower gamma band during REM sleep influences ongoing brain activity and induces self-reflective awareness in dreams. Other stimulation frequencies were not effective, suggesting that higher order consciousness is indeed related to synchronous oscillations around 25 and 40 Hz.

  14. 10 kHz High-Frequency Spinal Cord Stimulation for Chronic Axial Low Back Pain in Patients With No History of Spinal Surgery: A Preliminary, Prospective, Open Label and Proof-of-Concept Study.

    Science.gov (United States)

    Al-Kaisy, Adnan; Palmisani, Stefano; Smith, Thomas E; Pang, David; Lam, Khai; Burgoyne, William; Houghton, Russell; Hudson, Emma; Lucas, Jonathan

    2017-01-01

    To explore the effectiveness of 10 kHz high frequency spinal cord stimulation (HF10 therapy) treatment of chronic low back pain in patients who have not had spinal surgery. Patients with chronic low back pain without prior spinal surgery were evaluated by a team of spine surgeons to rule out any spinal pathology amenable to surgical interventions and by a multidisciplinary pain team to confirm eligibility for the study. After a successful (>50% back pain reduction) trial of HF10 therapy, enrolled subjects underwent permanent system implantation and were followed-up one year post-implant. About 95% of the enrolled subjects (20/21) received the permanent system. At 12 months post-implant, both back pain VAS score and ODI were significantly reduced compared with baseline values (by 73% and 48%, respectively); an estimated quality-adjusted life year gain of 0.47 and a reduction in opioid use by 64% was observed. Four more patients among those unable to work at baseline due to back pain were employed at 12 months post-implant. There were no serious adverse events. HF10 therapy may provide significant back pain relief, reduction in disability, improvement quality of life, and reduction in opioid use in chronic low back pain not resulting from spinal surgery. © 2016 The Authors. Neuromodulation: Technology at the Neural Interface published by Wiley Periodicals, Inc. on behalf of International Neuromodulation Society.

  15. growth stimulant

    African Journals Online (AJOL)

    Effects of timing and duration of supplementation of LIVFIT VET ® (growth stimulant) as substitute for fish meal on the growth performance, haematology and clinical enzymes concentration of growing pigs.

  16. Stimulated Brillouin processes in crystals and glasses

    International Nuclear Information System (INIS)

    Faris, G.W.; Hickman, A.P.

    1992-02-01

    The basic physics and material properties needed to describe and predict the Brillouin gain for a variety of materials have been investigated. Lawrence Livermore National Laboratory (LLNL) has identified transverse stimulated Brillouin scattering (SBS) as an important limiting mechanism in high power laser fusion systems. At sufficiently high laser intensities, SBS drives acoustic vibrations that can damage optical components. SRI has performed measurements and developed the corresponding theory for stimulated Brillouin gain spectroscopy in anisotropic crystals. Absolute Brillouin steady-state gain coefficients, linewidths, and frequency shifts have been determined at 532 nm for a number of optical materials of interest to LLNL. This knowledge can be used to select optical materials and devise suppression schemes that will allow much higher laser fluences to be used in laser fusion

  17. Use of a novel cell adhesion method and digital measurement to show stimulus-dependent variation in somatic and oral ciliary beat frequency in Paramecium.

    Science.gov (United States)

    Bell, Wade E; Hallworth, Richard; Wyatt, Todd A; Sisson, Joseph H

    2015-01-01

    When Paramecium encounters positive stimuli, the membrane hyperpolarizes and ciliary beat frequency increases. We adapted an established immobilization protocol using a biological adhesive and a novel digital analysis system to quantify beat frequency in immobilized Paramecium. Cells showed low mortality and demonstrated beat frequencies consistent with previous studies. Chemoattractant molecules, reduction in external potassium, and posterior stimulation all increased somatic beat frequency. In all cases, the oral groove cilia maintained a higher beat frequency than mid-body cilia, but only oral cilia from cells stimulated with chemoattactants showed an increase from basal levels. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

  18. Electrical stimulation in exercise training

    Science.gov (United States)

    Kroll, Walter

    1994-01-01

    muscle strength for over a century. Bigelow reported in 1894, for example, the use of electrical stimulation on a young man for the purpose of increasing muscle strength. Employing a rapidly alternating sinusoidal induced current and a dynamometer for strength testing, Bigelow reported that the total lifting capacity of a patient increased from 4328 pounds to 4639 pounds after only 25 minutes of stimulation. In 1965, Massey et al. reported on the use of an Isotron electrical stimulator that emitted a high frequency current. Interestingly enough, the frequencies used by Massey et al. and the frequencies used by Bigelow in 1894 were in the same range of frequencies reported by Kots as being the most effective in strength development. It would seem the Russian secret of high frequency electrical stimulation for strength development, then, is not a modern development at all.

  19. The frequency of clinical pregnancy and implantation rate after cultivation of embryos in a medium with granulocyte macrophage colony-stimulating factor (GM-CSF) in patients with preceding failed attempts of ART.

    Science.gov (United States)

    Tevkin, S; Lokshin, V; Shishimorova, M; Polumiskov, V

    2014-10-01

    The application in IVF practice of modern techniques can improve positive outcome of each cycle in the assisted reproductive technology (ART) programs and the effectiveness of treatment as a whole. There are embryos in the female reproductive tract in physiological medium which contain various cytokines and growth factors. It plays an important role in the regulation of normal embryonic development, improve implantation and subsequently optimizing the development of the fetus and the placenta. Granulocyte macrophage colony-stimulating factor (GM-CSF is one of the cytokines playing an important role in reproductive function. Addition of recombinant GM-CSF to the culture medium can makes closer human embryos culture to in vivo conditions and improve the efficacy ART cycles. The analysis of culture embryos in EmbryoGen medium has shown that fertilization rate embryo culture and transfer to patients with previous unsuccessful attempts increases clinical pregnancy rate compared to the control group 39.1 versus 27.8%, respectively. It is noted that the implantation rate (on 7 weeks' gestation) and progressive clinical pregnancy rate (on 12 weeks' gestation) were significantly higher in group embryos culture in EmbryoGen medium compared to standard combination of medium (ISM1+VA), and were 20.4 and 17.4% versus 11.6 and 9.1%, respectively.

  20. Brain Stimulation Therapies

    Science.gov (United States)

    ... Magnetic Seizure Therapy Deep Brain Stimulation Additional Resources Brain Stimulation Therapies Overview Brain stimulation therapies can play ... for a shorter recovery time than ECT Deep Brain Stimulation Deep brain stimulation (DBS) was first developed ...

  1. Mulheres com síndrome dos ovários policísticos apresentam maior frequência de síndrome metabólica independentemente do índice de massa corpóreo Women with polycystric ovary syndrome have a higher frequency of metabolic syndrome regardless of body mass index

    Directory of Open Access Journals (Sweden)

    Anderson Sanches Melo

    2012-01-01

    Full Text Available OBJETIVO: Avaliar a prevalência de síndrome metabólica e dos seus critérios definidores em mulheres com síndrome dos ovários policísticos do Sudeste brasileiro, estratificadas de acordo com o índice de massa corpóreo e comparadas com controles ovulatórias. MÉTODOS: Estudo transversal, realizado com 332 mulheres em idade reprodutiva, que foram divididas em dois grupo: Controle, constituído por 186 mulheres com ciclos menstruais regulares, sintomas ovulatórios e sem diagnóstico de síndrome dos ovários policísticos ou outra anovulação crônica; e Síndrome dos ovários policísticos, composto por 146 mulheres com o diagnóstico de síndrome dos ovários policísticos - Consenso de Rotterdam ASRM/ESHRE. Cada um destes grupos foi estratificado de acordo com o índice de massa corpóreo (PURPOSE: To assess the prevalence of metabolic syndrome and of its defining criteria in women with polycystic ovary syndrome from the Brazilian Southeast, who were stratified according to body mass index and compared to ovulatory controls. METHODS: This was a cross-sectional study conducted on 332 women of reproductive age, who were divided into two groups: Control, consisting of 186 women with regular menstrual cycles and ovulatory symptoms and without a diagnosis of polycystic ovary syndrome or other type of chronic anovulation, and the Polycystic ovary syndrome,Group, consisting of 146 women with a diagnosis of polycystic ovary syndrome (Rotterdam Consensus ASRM/ESHRE. Each group was stratified according to the body mass index, as follows: body mass index ( < 25 ≥25 and <30, and ≥ 30 kg/m². The frequencies of metabolic syndrome and of its defining criteria and the clinical and hormonal characteristics (follicle stimulating hormone, total testosterone, dehydroepiandrostenedione sulfate were analyzed. RESULTS: The frequency of metabolic syndrome was six times higher in the obese Polycystic ovary syndrome Group than among control women with the

  2. Comparação do índice de desconforto sensorial durante a estimulação elétrica neuromuscular com correntes excitomotoras de baixa e média frequência em mulheres saudáveis Comparison of the sensory discomfort index during neuromuscular electrical stimulation with low and medium excitomotor frequencies in healthy women

    Directory of Open Access Journals (Sweden)

    Richard Eloin Liebano

    2009-02-01

    Full Text Available INTRODUÇÃO: A estimulação elétrica neuromuscular é uma estratégia clínica para aumento da performance muscular. Sabe-se que um dos principais fatores limitantes da estimulação elétrica para aumento de força é o desconforto causado pelas correntes utilizadas. OBJETIVO: O objetivo deste estudo foi comparar o nível de desconforto sensorial causado por correntes de baixa e média freqüência na estimulação elétrica neuromuscular do músculo quadríceps femoral. MÉTODOS: Participaram do estudo 45 voluntárias saudáveis com idade entre 18 e 30 anos. Todas as voluntárias foram submetidas à estimulação elétrica com correntes de baixa e média freqüência. A análise do desconforto sensorial foi feita por meio de uma escala visual analógica (EVA. RESULTADOS: Os resultados revelaram um valor médio de 6,1 para o desconforto sensorial na estimulação de baixa freqüência (BF e de 6,4 para a estimulação de média freqüência (MF, não havendo diferença estatisticamente significante entre elas (p = 0,61. Em relação às intensidades utilizadas, a média foi de 45,64mA para a estimulação de BF e 121,67mA na estimulação com a MF, sendo essa diferença estatisticamente significante (p INTRODUCTION: Neuromuscular electrical stimulation is a clinical strategy for increasing of muscular performance. It is known that one of the main limiting factors of the electrical stimulation for strength increase is the discomfort caused by the currents used in the process. OBJECTIVE: The objective of this study was to compare the level of sensory discomfort caused by low and medium frequency currents in the neuromuscular electrical stimulation of the quadriceps femoris muscle. METHODS: Forty-five female healthy volunteers with age between 18 and 30 years participated in the study. All the volunteers were submitted to electrical stimulation with low and medium frequency. Sensory discomfort was measured using the Visual Analogue Scale (VAS

  3. The different effects of high-frequency stimulation of the nucleus accumbens shell and core on food consumption are possibly associated with different neural responses in the lateral hypothalamic area.

    Science.gov (United States)

    Wei, N; Wang, Y; Wang, X; He, Z; Zhang, M; Zhang, X; Pan, Y; Zhang, J; Qin, Z; Zhang, K

    2015-08-20

    Obesity may result from dysfunction of the reward system, especially in the nucleus accumbens (Acb). Based on this hypothesis, many researchers have tested the effect of high-frequency stimulation (HFS) of the Acb shell (Acb-Sh) and/or core (Acb-Co) on ingestive behaviors, but few studies have explored the possible mechanisms involved in the differences between the Acb-Sh and Acb-Co. The present study tested effects of HFS of the Acb-Sh and Acb-Co on high-fat food (HFF) consumption in rats after 24h of food deprivation. Microdialysis and electrophysiological experiments were carried out in awake rats to explore potential mechanisms. The results showed that the Acb-Sh decreased HFF consumption after food deprivation both during and post-HFS. However, HFS of the Acb-Co did not induce similar changes in food consumption. HFS of the Acb-Sh (Sh-HFS) induced an increase in GABA level in the lateral hypothalamic area (LHA) during both phases, whereas HFS of the Acb-Co (Co-HFS) did not exhibit similar effects. The electrophysiological experiment showed that nearly all the LHA neurons were inhibited by Sh-HFS, and the mean firing rate decreased significantly both during and post-HFS. In contrast, the mean firing rate of the LHA neurons did not exhibit clear changes during Co-HFS, although some individual neurons appeared to exhibit responses to Co-HFS. Considering all the data, we postulated that Sh-HFS, rather than Co-HFS, might inhibit palatable food consumption after food deprivation by decreasing the reward value of that food, which suggested that it might also disturb the process of developing obesity. The mechanisms involved in the different effects of Sh-HFS and Co-HFS on food consumption may be associated with different neural responses in the LHA. The Acb-Sh has abundant GABAergic projections to the LHA, whereas the Acb-Co has few or no GABAergic innervations to the LHA. Thus, neural activity in the LHA exhibits different responses to Sh-HFS and Co-HFS. Copyright

  4. Resting state cortical oscillations of patients with Parkinson disease and with and without subthalamic deep brain stimulation: a magnetoencephalography study.

    Science.gov (United States)

    Cao, Chunyan; Li, Dianyou; Jiang, Tianxiao; Ince, Nuri Firat; Zhan, Shikun; Zhang, Jing; Sha, Zhiyi; Sun, Bomin

    2015-04-01

    In this study, we investigate the modification to cortical oscillations of patients with Parkinson disease (PD) by subthalamic deep brain stimulation (STN-DBS). Spontaneous cortical oscillations of patients with PD were recorded with magnetoencephalography during on and off subthalamic nucleus deep brain stimulation states. Several features such as average frequency, average power, and relative subband power in regions of interest were extracted in the frequency domain, and these features were correlated with Unified Parkinson Disease Rating Scale III evaluation. The same features were also investigated in patients with PD without surgery and healthy controls. Patients with Parkinson disease without surgery compared with healthy controls had a significantly lower average frequency and an increased average power in 1 to 48 Hz range in whole cortex. Higher relative power in theta and simultaneous decrease in beta and gamma over temporal and occipital were also observed in patients with PD. The Unified Parkinson Disease Rating Scale III rigidity score correlated with the average frequency and with the relative power of beta and gamma in frontal areas. During subthalamic nucleus deep brain stimulation, the average frequency increased significantly when stimulation was on compared with off state. In addition, the relative power dropped in delta, whereas it rose in beta over the whole cortex. Through the course of stimulation, the Unified Parkinson Disease Rating Scale III rigidity and tremor scores correlated with the relative power of alpha over left parietal. Subthalamic nucleus deep brain stimulation improves the symptoms of PD by suppressing the synchronization of alpha rhythm in somatomotor region.

  5. New nonlinear-laser properties of ferroelectric Nd3+:Ba2NaNb5O15 - cw stimulated emission (4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 ), collinear and diffuse self-frequency doubling and summation

    International Nuclear Information System (INIS)

    Kaminskii, Alexandr A; Jaque, D; Garsia, Sole J; Capmany, J; Bagayev, S N; Ueda, Ken-ichi

    1999-01-01

    A new cw laser with self-frequency doubling and summation of 1-μm oscillation ( 4 F 3/2 → 4 I 11/2 ) was constructed on the basis of an orthorhombic Nd 3+ :Ba 2 NaNb 5 O 15 crystal. The 4 F 3/2 → 4 I 13/2 inter-Stark transition was used to excite cw 1.3-μm stimulated emission from this ferroelectric. (letters to the editor)

  6. Diferentes tempos de eletroestimulação neuromuscular (eenm de média frequência (kotz em cães Different times of neuromuscular electrical stimulation medium frequency (kotz in dogs

    Directory of Open Access Journals (Sweden)

    Charles Pelizzari

    2011-09-01

    Full Text Available O objetivo desta pesquisa foi empregar a estimulação elétrica neuromuscular (EENM de média frequência no músculo quadríceps femoral de cães com atrofia muscular induzida, avaliar o ganho de massa muscular e comparar a EENM sob diferentes tempos de tratamento. Foram utilizados oito cães, pesando entre 15 e 25kg e distribuídos aleatoriamente em dois grupos denominados de GI (30minutos e GII (60minutos. Para a indução da atrofia muscular, a articulação do joelho direito foi imobilizada por 30 dias por transfixação percutânea tipo II. Após a retirada do aparelho de imobilização, foi realizada a EENM nos cães dos grupos GI e GII três vezes por semana, com intervalo mínimo de 48 horas entre cada sessão, pelo período de 60 dias. Foram mensuradas a perimetria da coxa, goniometria dos joelhos, atividade da enzima creatina-quinase (CK e morfometria das fibras musculares do vasto lateral em cortes transversais colhido mediante a biópsia muscular. Não houve diferença quanto aos valores da perimetria da coxa e atividade da enzima CK. A goniometria revelou significância (PThe aim of this study was to use medium frequency Neuromuscular Electrical Stimulation (NMES in femoral quadriceps muscle of dogs with induced muscular atrophy to evaluate the occurrence of mass gain in these muscles and to compare NMES in different periods of treatment. Eight dogs, weighing between 15 and 25kg, were randomly placed in two groups: GI (NMES for 30min, GII, (NMES for 60min. For the muscular atrophy induction, the right knee was immobilized for 30 days by the percutaneous transfixation type II method. NMES was carried out in the dogs of which groups, three times a week, in between 48h each session, in a period of 60 days. The parameters measured were: thigh perimetry, knee goniometry, creatine kinase (CK enzyme activity and morphometry of the muscular fibers in transversal cuts of the vastus lateralis muscle, collected through a muscular biopsy

  7. Evaluation of the noradrenergic pathway and alpha-2 and beta-receptors in the modulation of the analgesia induced by transcutaneous electric nerve stimulation of high and low frequencies

    OpenAIRE

    Vasconcellos, Thiago Henrique Ferreira; Pantaleão, Patricia de Fátima; Teixeira, Dulcinéa Gonçalves; Santos, Ana Paula; Ferreira, Célio Marcos dos Reis

    2014-01-01

    Transcutaneous electric nerve stimulation is a noninvasive method used in clinical Physiotherapy to control acute or chronic pain. Different theories have been proposed to explain the mechanism of the analgesic action of transcutaneous electric nerve stimulation, as the participation of central and peripheral neurotransmitters. The aim of this study was to evaluate the involvement of noradrenergic pathway and of the receptors alfa-2 and beta in the modulation of analgesia produced by transcut...

  8. Differential requirements of CD4(+) T-cell signals for effector cytotoxic T-lymphocyte (CTL) priming and functional memory CTL development at higher CD8(+) T-cell precursor frequency.

    Science.gov (United States)

    Umeshappa, Channakeshava S; Nanjundappa, Roopa H; Xie, Yufeng; Freywald, Andrew; Xu, Qingyong; Xiang, Jim

    2013-04-01

    Increased CD8(+) T-cell precursor frequency (PF) precludes the requirement of CD4(+) helper T (Th) cells for primary CD8(+) cytotoxic T-lymphocyte (CTL) responses. However, the key questions of whether unhelped CTLs generated at higher PF are functional effectors, and whether unhelped CTLs can differentiate into functional memory cells at higher PF are unclear. In this study, ovalbumin (OVA) -pulsed dendritic cells (DC(OVA)) derived from C57BL/6, CD40 knockout (CD40(-/-)) or CD40 ligand knockout (CD40L(-/-)) mice were used to immunize C57BL/6, Ia(b-/-), CD40(-/-) or CD40L(-/-) mice, whose PF was previously increased with transfer of 1 × 10(6) CD8(+) T cells derived from OVA-specific T-cell receptor (TCR) transgenic OTI, OTI(CD40(-/-)) or OTI(CD40L(-/-)) mice. All the immunized mice were then assessed for effector and memory CTL responses. Following DC immunization, relatively comparable CTL priming occurred without CD4(+) T-cell help and Th-provided CD40/CD40L signalling. In addition, the unhelped CTLs were functional effectors capable of inducing therapeutic immunity against established OVA-expressing tumours. In contrast, the functional memory development of CTLs was severely impaired in the absence of CD4(+) T-cell help and CD40/CD40L signalling. Finally, unhelped memory CTLs failed to protect mice against lethal tumour challenge. Taken together, these results demonstrate that CD4(+) T-cell help at higher PF, is not required for effector CTL priming, but is required for functional memory CTL development against cancer. Our data may impact the development of novel preventive and therapeutic approaches in cancer patients with compromised CD4(+) T-cell functions. © 2012 Blackwell Publishing Ltd.

  9. Repetitive transcranial magnetic stimulation as a neuropsychiatric tool: present status and future potential.

    Science.gov (United States)

    Post, R M; Kimbrell, T A; McCann, U D; Dunn, R T; Osuch, E A; Speer, A M; Weiss, S R

    1999-03-01

    Repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising therapeutic intervention in the treatment of affective disorders. The differences in the type of electrical stimulation required for therapeutic efficacy by rTMS and electroconvulsive therapy (ECT) are discussed. In contrast to ECT, rTMS would not appear to require the generation of a major motor seizure to achieve therapeutic efficacy. Accordingly, it carries the potentially important clinical advantages of not requiring anesthesia and of avoiding side effects such as transient memory loss. Preclinical studies on long-term potentiation (LTP) and long-term depression (LTD) in hippocampal and amygdala slices, as well as clinical data from neuroimaging studies, have provided encouraging clues for potential frequency-dependent effects of rTMS. Preliminary evidence from position emission tomography (PET) scans suggests that higher frequency (20 Hz) stimulation may increase brain glucose metabolism in a transsynaptic fashion, whereas lower frequency (1 Hz) stimulation may decrease it. Therefore, the ability of rTMS to control the frequency as well as the location of stimulation, in addition to its other advantages, has opened up new possibilities for clinical explorations and treatments of neuropsychiatric conditions.

  10. Electrical stimulation of transplanted motoneurons improves motor unit formation

    Science.gov (United States)

    Liu, Yang; Grumbles, Robert M.

    2014-01-01

    Motoneurons die following spinal cord trauma and with neurological disease. Intact axons reinnervate nearby muscle fibers to compensate for the death of motoneurons, but when an entire motoneuron pool dies, there is complete denervation. To reduce denervation atrophy, we have reinnervated muscles in Fisher rats from local transplants of embryonic motoneurons in peripheral nerve. Since growth of axons from embryonic neurons is activity dependent, our aim was to test whether brief electrical stimulation of the neurons immediately after transplantation altered motor unit numbers and muscle properties 10 wk later. All surgical procedures and recordings were done in anesthetized animals. The muscle consequences of motoneuron death were mimicked by unilateral sciatic nerve section. One week later, 200,000 embryonic day 14 and 15 ventral spinal cord cells, purified for motoneurons, were injected into the tibial nerve 10–15 mm from the gastrocnemii muscles as the only neuron source for muscle reinnervation. The cells were stimulated immediately after transplantation for up to 1 h using protocols designed to examine differential effects due to pulse number, stimulation frequency, pattern, and duration. Electrical stimulation that included short rests and lasted for 1 h resulted in higher motor unit counts. Muscles with higher motor unit counts had more reinnervated fibers and were stronger. Denervated muscles had to be stimulated directly to evoke contractions. These results show that brief electrical stimulation of embryonic neurons, in vivo, has long-term effects on motor unit formation and muscle force. This muscle reinnervation provides the opportunity to use patterned electrical stimulation to produce functional movements. PMID:24848463

  11. A phase I study of different doses and frequencies of pegylated recombinant human granulocyte-colony stimulating factor (PEG rhG-CSF) in patients with standard-dose chemotherapy-induced neutropenia.

    Science.gov (United States)

    Qin, Yan; Han, Xiaohong; Wang, Lin; Du, Ping; Yao, Jiarui; Wu, Di; Song, Yuanyuan; Zhang, Shuxiang; Tang, Le; Shi, Yuankai

    2017-10-01

    The recommended dose of prophylactic pegylated recombinant human granulocyte-colony stimulating factor (PEG rhG-CSF) is 100 μg/kg once per cycle for patients receiving intense-dose chemotherapy. However, few data are available on the proper dose for patients receiving less-intense chemotherapy. The aim of this phase I study is to explore the proper dose and administration schedule of PEG rhG-CSF for patients receiving standard-dose chemotherapy. Eligible patients received 3-cycle chemotherapy every 3 weeks. No PEG rhG-CSF was given in the first cycle. Patients experienced grade 3 or 4 neutropenia would then enter the cycle 2 and 3. In cycle 2, patients received a single subcutaneous injection of prophylactic PEG rhG-CSF on d 3, and received half-dose subcutaneous injection in cycle 3 on d 3 and d 5, respectively. Escalating doses (30, 60, 100 and 200 μg/kg) of PEG rhG-CSF were investigated. A total of 26 patients were enrolled and received chemotherapy, in which 24 and 18 patients entered cycle 2 and cycle 3 treatment, respectively. In cycle 2, the incidence of grade 3 or 4 neutropenia for patients receiving single-dose PEG rhG-CSF of 30, 60, 100 and 200 μg/kg was 66.67%, 33.33%, 22.22% and 0, respectively, with a median duration less than 1 (0-2) d. No grade 3 or higher neutropenia was noted in cycle 3 in all dose cohorts. The pharmacokinetic and pharmacodynamic profiles of PEG rhG-CSF used in cancer patients were similar to those reported, as well as the safety. Double half dose administration model showed better efficacy result than a single dose model in terms of grade 3 neutropenia and above. The single dose of 60 μg/kg, 100 μg/kg and double half dose of 30 μg/kg were recommended to the phase II study, hoping to find a preferable method for neutropenia treatment.

  12. Effects of low frequency repetitive transcrinail magnetic stimulation on auditory hallucination in patients with schizophrenia%低频重复经颅磁刺激治疗精神分裂症患者的顽固性幻听

    Institute of Scientific and Technical Information of China (English)

    权文香; 周东丰; 王向群; 乔宏; 赵志宇; 张五芳; 任艳萍; 谭云龙; 王志仁; 田菊; 杨淑珍

    2012-01-01

    Objective: To investigate the effects and safety of low frequency repetitive transcrinail magnetic stimulation (rTMS) on obstinate auditory hallucination in schizophrenia patients. Methods: Totally 122 schizophrenia patients with obstinate hallucination who met the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-FV) from outpatient and inpatient department They were randomly allocated to receive 1 Hz (n =88,80%MT) or sham (n = 34) rTMS on left dorsolateral prefrontal cortex for 20 sessions (5 session per week and two weeks' break after 10 sessions). The Positive and Negative Syndrome Scale (PANSS), Audi-tory Hallucination Rating Scale( AHRS) and Clinical Global Impressions Scale( CGI) were used to assess the effect of rTMS on clinical features. Subjects in lHz group were followed up in time point of 3rd, 6th and 9th month after treatment Results: Totally 108 patients finished 20 treatment sessions. There were no significant differences between two groups in scores of PANSS, AHRS, CGI at any time point of treatment ( Ps > 0. 05). Meanwhile, in patients with course of disease less than 10 years [ (16. 2 ±4. 9 vs. 20. 3 ±4. 0) ] and 10 - 20 years [ (19. 2 ± 5. 5 vs. 23. 1 ± 6. 5], the AHRS scores were significantly lower in 1 Hz group than in the sham group (Ps < 0. 05). There was no other side effect complaints, except that 4 patients reported headache in treatment Conclusion: It suggests that 1 Hz repetitive transcrinail magnetic stimulation is a safe approach showing efficacy on obstinate auditory hallucination in schizophrenic patients whose course of disease are less than 20 years.%目的:探讨左背外侧前额叶低频重复经颅磁刺激(rTMS)治疗精神分裂症患者顽固性幻听的临床疗效.方法:本研究为随机双盲对照研究.根据美国精神障碍诊断统计手册第4版( DSM-Ⅳ)的诊断标准,选取122例伴顽固性幻听的精神分裂症患者按2∶1随机分为治疗组(n=88)

  13. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    Science.gov (United States)

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect–machine hybrid legged robot). PMID:25140875

  14. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Directory of Open Access Journals (Sweden)

    Feng Cao

    Full Text Available In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot.

  15. The Study of the Frequency Effect of Dynamic Compressive Loading on Primary Articular Chondrocyte Functions Using a Microcell Culture System

    Directory of Open Access Journals (Sweden)

    Wan-Ying Lin

    2014-01-01

    Full Text Available Compressive stimulation can modulate articular chondrocyte functions. Nevertheless, the relevant studies are not comprehensive. This is primarily due to the lack of cell culture apparatuses capable of conducting the experiments in a high throughput, precise, and cost-effective manner. To address the issue, we demonstrated the use of a perfusion microcell culture system to investigate the stimulating frequency (0.5, 1.0, and 2.0 Hz effect of compressive loading (20% and 40% strain on the functions of articular chondrocytes. The system mainly integrates the functions of continuous culture medium perfusion and the generation of pneumatically-driven compressive stimulation in a high-throughput micro cell culture system. Results showed that the compressive stimulations explored did not have a significant impact on chondrocyte viability and proliferation. However, the metabolic activity of chondrocytes was significantly affected by the stimulating frequency at the higher compressive strain of 40% (2 Hz, 40% strain. Under the two compressive strains studied, the glycosaminoglycans (GAGs synthesis was upregulated when the stimulating frequency was set at 1 Hz and 2 Hz. However, the stimulating frequencies explored had no influence on the collagen production. The results of this study provide useful fundamental insights that will be helpful for cartilage tissue engineering and cartilage rehabilitation.

  16. Parametric changes in response equilibrium during an intra-cranial self stimulation (ICSS) task: can reward value be assessed independently of absolute threshold?

    Science.gov (United States)

    Easterling, K W; Holtzman, S G

    1997-01-01

    Traditional ICSS methodologies have attempted to evaluate changes in the rewarding value of brain stimulation by assessing the lowest value of the stimulation that will support responding. However, orderly changes in suprathreshold indicants of hedonic magnitude such as titration point have been shown. In the present experiments, rats were trained to respond on two ICSS autotitration schedules in which every response on one lever produced stimulation of the medial forebrain bundle, and every Xth response decreased either the stimulation current or the stimulation frequency. At any time, a response on a second "reset" lever restored the stimulation current or frequency available on the stimulation lever to its starting level and operationally defined changes in "reward value". In order to study this titration point measure, two response requirements (responses/stepdown; step size) and two stimulation parameters (initial stimulation level; train duration) were systematically varied. Under both current and frequency titration schedules, data indicated that response rate and titration point remained stable over repeated trials and multiple testing days--parameters being constant. Across all conditions, compared to the frequency titration schedule, subjects responding under the current titration schedule showed significantly higher titration points and lower rates of responding. Indicating the independence of rate and titration point data, parametric manipulations did not affect titration point and rate data concurrently. Results support the conclusion that titration point is a relative measure of "reward value" that is generally independent of response rate, but that is affected by manipulations that alter the amount of stimulation available between "resets". Additional work is needed in order to determine the relationship between the magnitude of stimulation needed to maintain minimal responding and that needed to maintain response equilibrium in an autotitration task.

  17. Higher Education

    African Journals Online (AJOL)

    Kunle Amuwo: Higher Education Transformation: A Paradigm Shilt in South Africa? ... ty of such skills, especially at the middle management levels within the higher ... istics and virtues of differentiation and diversity. .... may be forced to close shop for lack of capacity to attract ..... necessarily lead to racial and gender equity,.

  18. Frequency Hopping Transceiver Multiplexer

    Science.gov (United States)

    1983-03-01

    ATC 17 ULR IHQ OCLI CPCTR ULTRA HIGH "OQS" UP TO 4X HIGHER THAN BEST INDUS- TRY STANDARD (ATC 100). MICROWAVE POWER, CURRENT. AND 0 RATINGS5...Q"W were assigned to element (FigC-2); which will be modelled into the transformer previously ment td . The center frequencies, "Q", frequency range...of the TD 1288 system. Temperature stability, change with time or storage. Flexure Frequency, or non-linear change over bandwidth. * Humidity

  19. Autoantibody frequency in celiac disease

    Directory of Open Access Journals (Sweden)

    Erkan Caglar

    2009-01-01

    Full Text Available AIM: In our study, we investigated the levels of glutamic acid decarboxylase antibody (anti-GAD, islet cell antibody (ICA, thyroperoxidase antibody (anti-TPO, thyroglobulin antibody (anti-TG, antinuclear antibodies (FANA, antibodies to double-stranded DNA (anti-ds DNA, antibody to Sjögren syndrome A antigen (anti-SSA, antibody to Sjögren syndrome B antigen (anti-SSB, Smith antibody (anti-Sm, smooth muscle antibodies (ASMA, and antimitochondrial antibody liver-kidney microsome (AMA-LKM in patients with celiac disease as compared to healthy controls and autoimmune hypothyroid patients. MATERIALS AND METHODS: A total of 31 patients with celiac disease, 34 patients with autoimmune hypothyroidism and 29 healthy subjects were included in this study. Anti-SSA, anti-SSB, anti-Sm, anti-ds DNA, anti-GAD, anti-TPO and anti-TG were studied by Enzyme-Linked Immunosorbent Assay (ELISA, and AMA-LKM, ASMA, ANA and ICA were studied by immunofluorescence. Clinical data and the results of free thyroxine-thyroid stimulating hormone (FT4-TSH were collected from the patients' files by retrospective analysis. SPSS ver 13.0 was used for data analysis, and the χ2 method was used for comparisons within groups. RESULTS: The frequency of anti-SSA, anti-SSB, anti-GAD, anti-Sm, anti-ds DNA, AMA-LKM, ASMA, ANA and ICA were not significantly different between the groups. Levels of anti-TPO and anti-TG antibodies were found to be significantly higher (<0.001 in autoimmune hypothyroid patients when compared with other groups. CONCLUSION: In previous studies, an increased frequency of autoimmune diseases of other systems has been reported in patients with celiac disease. We found that the frequency of autoimmune antibodies specific for other autoimmune diseases was not higher in celiac disease.

  20. Transcranial alternating current stimulation (tACS

    Directory of Open Access Journals (Sweden)

    Andrea eAntal

    2013-06-01

    Full Text Available Transcranial alternating current stimulation (tACS seems likely to open a new era of the field of noninvasive electrical stimulation of the human brain by directly interfering with cortical rhythms. It is expected to synchronize (by one single resonance frequency or desynchronize (e.g. by the application of several frequencies cortical oscillations. If applied long enough it may cause neuroplastic effects. In the theta range it may improve cognition when applied in phase. Alpha rhythms could improve motor performance, whereas beta intrusion may deteriorate them. TACS with both alpha and beta frequencies has a high likelihood to induce retinal phosphenes. Gamma intrusion can possibly interfere with attention. Stimulation in the ripple range induces intensity dependent inhibition or excitation in the motor cortex most likely by entrainment of neuronal networks, whereas stimulation in the low kHz range induces excitation by neuronal membrane interference. TACS in the 200 kHz range may have a potential in oncology.

  1. An improved genetic algorithm for designing optimal temporal patterns of neural stimulation

    Science.gov (United States)

    Cassar, Isaac R.; Titus, Nathan D.; Grill, Warren M.

    2017-12-01

    Objective. Electrical neuromodulation therapies typically apply constant frequency stimulation, but non-regular temporal patterns of stimulation may be more effective and more efficient. However, the design space for temporal patterns is exceedingly large, and model-based optimization is required for pattern design. We designed and implemented a modified genetic algorithm (GA) intended for design optimal temporal patterns of electrical neuromodulation. Approach. We tested and modified standard GA methods for application to designing temporal patterns of neural stimulation. We evaluated each modification individually and all modifications collectively by comparing performance to the standard GA across three test functions and two biophysically-based models of neural stimulation. Main results. The proposed modifications of the GA significantly improved performance across the test functions and performed best when all were used collectively. The standard GA found patterns that outperformed fixed-frequency, clinically-standard patterns in biophysically-based models of neural stimulation, but the modified GA, in many fewer iterations, consistently converged to higher-scoring, non-regular patterns of stimulation. Significance. The proposed improvements to standard GA methodology reduced the number of iterations required for convergence and identified superior solutions.

  2. Frequency- and amplitude-transitioned waveforms mitigate the onset response in high-frequency nerve block

    Science.gov (United States)

    Gerges, Meana; Foldes, Emily L.; Ackermann, D. Michael; Bhadra, Narendra; Bhadra, Niloy; Kilgore, Kevin L.

    2010-12-01

    High-frequency alternating currents (HFAC) have proven to be a reversible and rapid method of blocking peripheral nerve conduction, holding promise for treatment of disorders associated with undesirable neuronal activity. The delivery of HFAC is characterized by a transient period of neural firing at its inception, termed the 'onset response'. The onset response is minimized for higher frequencies and higher amplitudes, but requires larger currents. However, the complete block can be maintained at lower frequencies and amplitudes, using lower currents. In this in vivo study on whole mammalian peripheral nerves, we demonstrate a method to minimize the onset response by initiating the block using a stimulation paradigm with a high frequency and large amplitude, and then transitioning to a low-frequency and low-amplitude waveform, reducing the currents required to maintain the conduction block. In five of six animals, it was possible to transition from a 30 kHz to a 10 kHz waveform without inducing any transient neural firing. The minimum transition time was 0.03 s. Transition activity was minimized or eliminated with longer transition times. The results of this study show that this method is feasible for achieving a nerve block with minimal onset responses and current amplitude requirements.

  3. Testing a linear time invariant model for skin conductance responses by intraneural recording and stimulation.

    Science.gov (United States)

    Gerster, Samuel; Namer, Barbara; Elam, Mikael; Bach, Dominik R

    2018-02-01

    Skin conductance responses (SCR) are increasingly analyzed with model-based approaches that assume a linear and time-invariant (LTI) mapping from sudomotor nerve (SN) activity to observed SCR. These LTI assumptions have previously been validated indirectly, by quantifying how much variance in SCR elicited by sensory stimulation is explained under an LTI model. This approach, however, collapses sources of variability in the nervous and effector organ systems. Here, we directly focus on the SN/SCR mapping by harnessing two invasive methods. In an intraneural recording experiment, we simultaneously track SN activity and SCR. This allows assessing the SN/SCR relationship but possibly suffers from interfering activity of non-SN sympathetic fibers. In an intraneural stimulation experiment under regional anesthesia, such influences are removed. In this stimulation experiment, about 95% of SCR variance is explained under LTI assumptions when stimulation frequency is below 0.6 Hz. At higher frequencies, nonlinearities occur. In the intraneural recording experiment, explained SCR variance is lower, possibly indicating interference from non-SN fibers, but higher than in our previous indirect tests. We conclude that LTI systems may not only be a useful approximation but in fact a rather accurate description of biophysical reality in the SN/SCR system, under conditions of low baseline activity and sporadic external stimuli. Intraneural stimulation under regional anesthesia is the most sensitive method to address this question. © 2017 The Authors. Psychophysiology published by Wiley Periodicals, Inc. on behalf of Society for Psychophysiological Research.

  4. Peripheral blood mononuclear cells of patients with latent autoimmune diabetes secrete higher levels of pro- & anti-inflammatory cytokines compared to those with type-1 diabetes mellitus following in vitro stimulation with β-cell autoantigens

    Directory of Open Access Journals (Sweden)

    Darshan Badal

    2017-01-01

    Interpretation & conclusions: There are differences in the portfolio of cytokine secretion in diabetic subjects with varying rates of β-cell destruction as LADA subjects secrete higher levels of both pro- and anti-inflammatory cytokines on exposure to β-cell autoantigens, thus highlighting another distinguishing feature in the pathophysiology of the two forms of autoimmune diabetes.

  5. Higher Education

    Science.gov (United States)

    & Development (LDRD) National Security Education Center (NSEC) Office of Science Programs Richard P Databases National Security Education Center (NSEC) Center for Nonlinear Studies Engineering Institute Scholarships STEM Education Programs Teachers (K-12) Students (K-12) Higher Education Regional Education

  6. Lion's Mane, Hericium erinaceus and Tiger Milk, Lignosus rhinocerotis (Higher Basidiomycetes) Medicinal Mushrooms Stimulate Neurite Outgrowth in Dissociated Cells of Brain, Spinal Cord, and Retina: An In Vitro Study.

    Science.gov (United States)

    Samberkar, Snehlata; Gandhi, Sivasangkary; Naidu, Murali; Wong, Kah-Hui; Raman, Jegadeesh; Sabaratnam, Vikineswary

    2015-01-01

    Neurodegenerative disease is defined as a deterioration of the nervous system in the intellectual and cognitive capabilities. Statistics show that more than 80-90 million individuals age 65 and above in 2050 may be affected by neurodegenerative conditions like Alzheimer's and Parkinson's disease. Studies have shown that out of 2000 different types of edible and/or medicinal mushrooms, only a few countable mushrooms have been selected until now for neurohealth activity. Hericium erinaceus is one of the well-established medicinal mushrooms for neuronal health. It has been documented for its regenerative capability in peripheral nerve. Another mushroom used as traditional medicine is Lignosus rhinocerotis, which has been used for various illnesses. It has been documented for its neurite outgrowth potential in PC12 cells. Based on the regenerative capabilities of both the mushrooms, priority was given to select them for our study. The aim of this study was to investigate the potential of H. erinaceus and L. rhinocerotis to stimulate neurite outgrowth in dissociated cells of brain, spinal cord, and retina from chick embryo when compared to brain derived neurotrophic factor (BDNF). Neurite outgrowth activity was confirmed by the immu-nofluorescence method in all tissue samples. Treatment with different concentrations of extracts resulted in neuronal differentiation and neuronal elongation. H. erinaceus extract at 50 µg/mL triggered neurite outgrowth at 20.47%, 22.47%, and 21.70% in brain, spinal cord, and retinal cells. L. rhinocerotis sclerotium extract at 50 µg/mL induced maximum neurite outgrowth of 20.77% and 24.73% in brain and spinal cord, whereas 20.77% of neurite outgrowth was observed in retinal cells at 25 µg/mL, respectively.

  7. Mimicking muscle activity with electrical stimulation

    Science.gov (United States)

    Johnson, Lise A.; Fuglevand, Andrew J.

    2011-02-01

    Functional electrical stimulation is a rehabilitation technology that can restore some degree of motor function in individuals who have sustained a spinal cord injury or stroke. One way to identify the spatio-temporal patterns of muscle stimulation needed to elicit complex upper limb movements is to use electromyographic (EMG) activity recorded from able-bodied subjects as a template for electrical stimulation. However, this requires a transfer function to convert the recorded (or predicted) EMG signals into an appropriate pattern of electrical stimulation. Here we develop a generalized transfer function that maps EMG activity into a stimulation pattern that modulates muscle output by varying both the pulse frequency and the pulse amplitude. We show that the stimulation patterns produced by this transfer function mimic the active state measured by EMG insofar as they reproduce with good fidelity the complex patterns of joint torque and joint displacement.

  8. CpG Oligonucleotide and Interleukin 2 stimulation enables higher cytogenetic abnormality detection rates than 12-o-tetradecanolyphorbol-13-acetate in Asian patients with B-cell chronic lymphocytic leukemia (B-CLL).

    Science.gov (United States)

    Liaw, Fiona Pui San; Lau, Lai Ching; Lim, Alvin Soon Tiong; Lim, Tse Hui; Lee, Geok Yee; Tien, Sim Leng

    2014-12-01

    The present study was designed to compare abnormality detection rates using DSP30 + IL2 and 12-O-Tetradecanoylphorbol-13-acetate (TPA) in Asian patients with B-CLL. Hematological specimens from 47 patients (29 newly diagnosed, 18 relapsed) were established as 72 h-DSP30 + IL2 and TPA cultures. Standard methods were employed to identify clonal aberrations by conventional cytogenetics (CC). The B-CLL fluorescence in situ hybridization (FISH) panel comprised ATM, CEP12, D13S25, and TP53 probes. DSP30 + IL2 cultures had a higher chromosomal abnormality detection rate (67 %) compared to TPA (44 %, p 0.05). Thirteen cases with abnormalities were found exclusively in DSP30 + IL2 cultures compared to one found solely in TPA cultures. DSP30 + IL2 cultures were comparable to the FISH panel in detecting 11q-, +12 and 17p- but not 13q-. It also has a predilection for 11q- bearing leukemic cells compared to TPA. FISH had a higher abnormality detection rate (84.1 %) compared to CC (66.0 %) with borderline significance (p = 0.051), albeit limited by its coverage. In conclusion, DSP30 + IL2 showed a higher abnormality detection rate. However, FISH is indispensable to circumvent low mitotic indices and detect subtle abnormalities.

  9. Resonant Impulsive Stimulated Raman Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, A; Chesnoy, J

    1988-03-15

    Using a femtosecond dye laser, we observe in real-time vibrational oscillations excited by impulsive stimulated Raman scattering (ISRS) close to an electronic resonance. We perform single-beam Raman excitation and probe the driven coherence by a polarization-sensitive detection. We demonstrate for the first time impulsively Raman-induced dichroism, birefringence as well as frequency and time delay shifts. We analyse the characteristics of resonant ISRS on a vibrational mode of a dye molecule (malachite green) in solution.

  10. Resonant Impulsive Stimulated Raman Scattering

    International Nuclear Information System (INIS)

    Mokhtari, A.; Chesnoy, J.

    1988-01-01

    Using a femtosecond dye laser, we observe in real-time vibrational oscillations excited by impulsive stimulated Raman scattering (ISRS) close to an electronic resonance. We perform single-beam Raman excitation and probe the driven coherence by a polarization-sensitive detection. We demonstrate for the first time impulsively Raman-induced dichroism, birefringence as well as frequency and time delay shifts. We analyse the characteristics of resonant ISRS on a vibrational mode of a dye molecule (malachite green) in solution

  11. Comparison of fMRI BOLD response patterns by electrical stimulation of the ventroposterior complex and medial thalamus of the rat.

    Directory of Open Access Journals (Sweden)

    Pai-Feng Yang

    Full Text Available The objective of this study was to compare the functional connectivity of the lateral and medial thalamocortical pain pathways by investigating the blood oxygen level-dependent (BOLD activation patterns in the forebrain elicited by direct electrical stimulation of the ventroposterior (VP and medial (MT thalamus. An MRI-compatible stimulation electrode was implanted in the VP or MT of α-chloralose-anesthetized rats. Electrical stimulation was applied to the VP or MT at various intensities (50 µA to 300 µA and frequencies (1 Hz to 12 Hz. BOLD responses were analyzed in the ipsilateral forelimb region of the primary somatosensory cortex (iS1FL after VP stimulation and in the ipsilateral cingulate cortex (iCC after MT stimulation. When stimulating the VP, the strongest activation occurred at 3 Hz. The stimulation intensity threshold was 50 µA and the response rapidly peaked at 100 µA. When stimulating the MT, The optimal frequency for stimulation was 9 Hz or 12 Hz, the stimulation intensity threshold was 100 µA and we observed a graded increase in the BOLD response following the application of higher intensity stimuli. We also evaluated c-Fos expression following the application of a 200-µA stimulus. Ventroposterior thalamic stimulation elicited c-Fos-positivity in few cells in the iS1FL and caudate putamen (iCPu. Medial thalamic stimulation, however, produced numerous c-Fos-positive cells in the iCC and iCPu. The differential BOLD responses and c-Fos expressions elicited by VP and MT stimulation indicate differences in stimulus-response properties of the medial and lateral thalamic pain pathways.

  12. Higher Education.

    Science.gov (United States)

    Hendrickson, Robert M.

    This chapter reports 1982 cases involving aspects of higher education. Interesting cases noted dealt with the federal government's authority to regulate state employees' retirement and raised the questions of whether Title IX covers employment, whether financial aid makes a college a program under Title IX, and whether sex segregated mortality…

  13. Human progenitor cells rapidly mobilized by AMD3100 repopulate NOD/SCID mice with increased frequency in comparison to cells from the same donor mobilized by granulocyte colony stimulating factor

    DEFF Research Database (Denmark)

    Hess, David A; Bonde, Jesper; Craft, Timothy P

    2007-01-01

    ) or purified CD34(+) cells was compared at limiting dilution into NOD/SCID mice. Human AMD3100-mobilized MNC possessed enhanced repopulating frequency in comparison to G-CSF-mobilized MNC from paired donors, and purified CD34(+) progenitors were at least as efficient as the G-CSF mobilized cells....... The frequencies of NOD/SCID repopulating cells (SRC) were 1 SRC in 8.7 x 10(6) AMD3100-mobilized MNC compared to 1 SRC in 29.0 x 10(6) G-CSF-mobilized MNC, and 1 SRC in 1.2 x 10(5) AMD3100-mobilized CD34(+) cells compared to 1 SRC in 1.8 x 10(5) G-CSF-mobilized CD34(+) cells. Hematopoietic differentiation...

  14. Ovarian stimulation and embryo quality

    NARCIS (Netherlands)

    Baart, Esther; Macklon, Nick S.; Fauser, Bart J. C. M.

    To Study the effects of different ovarian stimulation approaches on oocyte and embryo quality, it is imperative to assess embryo quality with a reliable and objective method. Embryos rated as high quality by standardized morphological assessment are associated with higher implantation and pregnancy

  15. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  16. Short-term low-frequency electrical stimulation enhanced remyelination of injured peripheral nerves by inducing the promyelination effect of brain-derived neurotrophic factor on Schwann cell polarization.

    Science.gov (United States)

    Wan, Lidan; Xia, Rong; Ding, Wenlong

    2010-09-01

    Electrical stimulation (ES) has been found to aid repair of nerve injuries and have been shown to increase and direct neurite outgrowth during stimulation. However, the effect of ES on peripheral remyelination after nerve damage has been investigated less well, and the mechanism underlying its action remains unclear. In the present study, the crush-injured sciatic nerves in rats were subjected to 1 hr of continuous ES (20 Hz, 100 microsec, 3 V). Electron microscopy and nerve morphometry were performed to investigate the extent of regenerated nerve myelination. The expression profiles of P0, Par-3, and brain-derived neurotrophic factor (BDNF) in the injuried sciatic nerves and in the dorsal root ganglion neuron/Schwann cell cocultures were examined by Western blotting. Par-3 localization in the sciatic nerves was determined by immunohistochemistry to demonstrate Schwann cell polarization during myelination. We reported that 20-Hz ES increased the number of myelinated fibers and the thickness myelin sheath at 4 and 8 weeks postinjury. P0 level in the ES-treated groups, both in vitro and in vivo, was enhanced compared with the controls. The earlier peak of Par-3 in the ES-treated groups indicated an earlier initiation of Schwann cell myelination. Additionally, ES significantly elevated BDNF expression in nerve tissues and in cocultures. ES on the site of nerve injury potentiates axonal regrowth and myelin maturation during peripheral nerve regeneration. Furthermore, the therapeutic actions of ES on myelination are mediated via enhanced BDNF signals, which drive the promyelination effect on Schwann cells at the onset of myelination.

  17. hebp3, a novel member of the heme-binding protein gene family, is expressed in the medaka meninges with higher abundance in females due to a direct stimulating action of ovarian estrogens.

    Science.gov (United States)

    Nakasone, Kiyoshi; Nagahama, Yoshitaka; Okubo, Kataaki

    2013-02-01

    The brains of teleost fish exhibit remarkable sexual plasticity throughout their life span. To dissect the molecular basis for the development and reversal of sex differences in the teleost brain, we screened for genes differentially expressed between sexes in the brain of medaka (Oryzias latipes). One of the genes identified in the screen as being preferentially expressed in females was found to be a new member of the heme-binding protein gene family that includes hebp1 and hebp2 and was designated here as hebp3. The medaka hebp3 is expressed in the meninges with higher abundance in females, whereas there is no expression within the brain parenchyma. This female-biased expression of hebp3 is not attributable to the direct action of sex chromosome genes but results from the transient and reversible action of estrogens derived from the ovary. Moreover, estrogens directly activate the transcription of hebp3 via a palindromic estrogen-responsive element in the hebp3 promoter. Taken together, our findings demonstrate that hebp3 is a novel transcriptional target of estrogens, with female-biased expression in the meninges. The definite but reversible sexual dimorphism of the meningeal hebp3 expression may contribute to the development and reversal of sex differences in the teleost brain.

  18. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  19. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  20. Evaluation of Round Window Stimulation Performance in Otosclerosis Using Finite Element Modeling

    Directory of Open Access Journals (Sweden)

    Shanguo Yang

    2016-01-01

    Full Text Available Round window (RW stimulation is a new type of middle ear implant’s application for treating patients with middle ear disease, such as otosclerosis. However, clinical outcomes show a substantial degree of variability. One source of variability is the variation in the material properties of the ear components caused by the disease. To investigate the influence of the otosclerosis on the performance of the RW stimulation, a human ear finite element model including middle ear and cochlea was established based on a set of microcomputerized tomography section images of a human temporal bone. Three characteristic changes of the otosclerosis in the auditory system were simulated in the FE model: stapedial annular ligament stiffness enlargement, stapedial abnormal bone growth, and partial fixation of the malleus. The FE model was verified by comparing the model-predicted results with published experimental measurements. The equivalent sound pressure (ESP of RW stimulation was calculated via comparing the differential intracochlear pressure produced by the RW stimulation and the normal eardrum sound stimulation. The results show that the increase of stapedial annular ligament and partial fixation of the malleus decreases RW stimulation’s ESP prominently at lower frequencies. In contrast, the stapedial abnormal bone growth deteriorates RW stimulation’s ESP severely at higher frequencies.

  1. Transcranial alternating current stimulation: A review of the underlying mechanisms and modulation of cognitive processes

    Directory of Open Access Journals (Sweden)

    Christoph S Herrmann

    2013-06-01

    Full Text Available Brain oscillations of different frequencies have been associated with a variety of cognitive functions. Convincing evidence supporting those associations has been provided by studies using intracranial stimulation, pharmacological interventions and lesion studies. The emergence of novel non-invasive brain stimulation techniques like repetitive transcranial magnetic stimulation (rTMS and transcranial alternating current stimulation (tACS now allows to modulate brain oscillations directly. Particularly, tACS offers the unique opportunity to causally link brain oscillations of a specific frequency range to cognitive processes, because it uses sinusoidal currents that are bound to one frequency only. Using tACS allows to modulate brain oscillations and in turn to influence cognitive processes, thereby demonstrating the causal link between the two. Here, we review findings about the physiological mechanism of tACS and studies that have used tACS to modulate basic motor and sensory processes as well as higher cognitive processes like memory, ambiguous perception, and decision making.

  2. Optical stimulation of peripheral nerves in vivo

    Science.gov (United States)

    Wells, Jonathon D.

    This dissertation documents the emergence and validation of a new clinical tool that bridges the fields of biomedical optics and neuroscience. The research herein describes an innovative method for direct neurostimulation with pulsed infrared laser light. Safety and effectiveness of this technique are first demonstrated through functional stimulation of the rat sciatic nerve in vivo. The Holmium:YAG laser (lambda = 2.12 mum) is shown to operate at an optimal wavelength for peripheral nerve stimulation with advantages over standard electrical neural stimulation; including contact-free stimulation, high spatial selectivity, and lack of a stimulation artifact. The underlying biophysical mechanism responsible for transient optical nerve stimulation appears to be a small, absorption driven thermal gradient sustained at the axonal layer of nerve. Results explicitly prove that low frequency optical stimulation can reliably stimulate without resulting in tissue thermal damage. Based on the positive results from animal studies, these optimal laser parameters were utilized to move this research into the clinic with a combined safety and efficacy study in human subjects undergoing selective dorsal rhizotomy. The clinical Holmium:YAG laser was used to effectively stimulate human dorsal spinal roots and elicit functional muscle responses recorded during surgery without evidence of nerve damage. Overall these results predict that this technology can be a valuable clinical tool in various neurosurgical applications.

  3. Stimulated coherent transition radiation

    International Nuclear Information System (INIS)

    Hung-chi Lihn.

    1996-03-01

    Coherent radiation emitted from a relativistic electron bunch consists of wavelengths longer than or comparable to the bunch length. The intensity of this radiation out-numbers that of its incoherent counterpart, which extends to wavelengths shorter than the bunch length, by a factor equal to the number of electrons in the bunch. In typical accelerators, this factor is about 8 to 11 orders of magnitude. The spectrum of the coherent radiation is determined by the Fourier transform of the electron bunch distribution and, therefore, contains information of the bunch distribution. Coherent transition radiation emitted from subpicosecond electron bunches at the Stanford SUNSHINE facility is observed in the far-infrared regime through a room-temperature pyroelectric bolometer and characterized through the electron bunch-length study. To measure the bunch length, a new frequency-resolved subpicosecond bunch-length measuring system is developed. This system uses a far-infrared Michelson interferometer to measure the spectrum of coherent transition radiation through optical autocorrelation with resolution far better than existing time-resolved methods. Hence, the radiation spectrum and the bunch length are deduced from the autocorrelation measurement. To study the stimulation of coherent transition radiation, a special cavity named BRAICER is invented. Far-infrared light pulses of coherent transition radiation emitted from electron bunches are delayed and circulated in the cavity to coincide with subsequent incoming electron bunches. This coincidence of light pulses with electron bunches enables the light to do work on electrons, and thus stimulates more radiated energy. The possibilities of extending the bunch-length measuring system to measure the three-dimensional bunch distribution and making the BRAICER cavity a broadband, high-intensity, coherent, far-infrared light source are also discussed

  4. [Electrical acupoint stimulation increases athletes' rapid strength].

    Science.gov (United States)

    Yang, Hua-yuan; Liu, Tang-yi; Kuai, Le; Gao, Ming

    2006-05-01

    To search for a stimulation method for increasing athletes' performance. One hundred and fifty athletes were randomly divided into a trial group and a control group, 75 athletes in each group. Acupoints were stimulated with audio frequency pulse modulated wave and multi-blind method were used to investigate effects of the electric stimulation of acupoints on 30-meter running, standing long jumping and Cybex isokinetic testing index. The acupoint electric stimulation method could significantly increase athlete's performance (P < 0.05), and the biomechanical indexes, maximal peak moment of force (P < 0.05), force moment accelerating energy (P < 0.05) and average power (P < 0.05). Electrical acupoint stimulation can enhance athlete's rapid strength.

  5. Optimized temporal pattern of brain stimulation designed by computational evolution.

    Science.gov (United States)

    Brocker, David T; Swan, Brandon D; So, Rosa Q; Turner, Dennis A; Gross, Robert E; Grill, Warren M

    2017-01-04

    Brain stimulation is a promising therapy for several neurological disorders, including Parkinson's disease. Stimulation parameters are selected empirically and are limited to the frequency and intensity of stimulation. We varied the temporal pattern of deep brain stimulation to ameliorate symptoms in a parkinsonian animal model and in humans with Parkinson's disease. We used model-based computational evolution to optimize the stimulation pattern. The optimized pattern produced symptom relief comparable to that from standard high-frequency stimulation (a constant rate of 130 or 185 Hz) and outperformed frequency-matched standard stimulation in a parkinsonian rat model and in patients. Both optimized and standard high-frequency stimulation suppressed abnormal oscillatory activity in the basal ganglia of rats and humans. The results illustrate the utility of model-based computational evolution of temporal patterns to increase the efficiency of brain stimulation in treating Parkinson's disease and thereby reduce the energy required for successful treatment below that of current brain stimulation paradigms. Copyright © 2017, American Association for the Advancement of Science.

  6. Selective activation of primary afferent fibers evaluated by sine-wave electrical stimulation

    Directory of Open Access Journals (Sweden)

    Katafuchi Toshihiko

    2005-03-01

    Full Text Available Abstract Transcutaneous sine-wave stimuli at frequencies of 2000, 250 and 5 Hz (Neurometer are thought to selectively activate Aβ, Aδ and C afferent fibers, respectively. However, there are few reports to test the selectivity of these stimuli at the cellular level. In the present study, we analyzed action potentials (APs generated by sine-wave stimuli applied to the dorsal root in acutely isolated rat dorsal root ganglion (DRG preparations using intracellular recordings. We also measured excitatory synaptic responses evoked by transcutaneous stimuli in substantia gelatinosa (SG neurons of the spinal dorsal horn, which receive inputs predominantly from C and Aδ fibers, using in vivo patch-clamp recordings. In behavioral studies, escape or vocalization behavior of rats was observed with both 250 and 5 Hz stimuli at intensity of ~0.8 mA (T5/ T250, whereas with 2000 Hz stimulation, much higher intensity (2.14 mA, T2000 was required. In DRG neurons, APs were generated at T5/T250 by 2000 Hz stimulation in Aβ, by 250 Hz stimulation both in Aβ and Aδ, and by 5 Hz stimulation in all three classes of DRG neurons. However, the AP frequencies elicited in Aβ and Aδ by 5 Hz stimulation were much less than those reported previously in physiological condition. With in vivo experiments large amplitude of EPSCs in SG neurons were elicited by 250 and 5 Hz stimuli at T5/ T250. These results suggest that 2000 Hz stimulation excites selectively Aβ fibers and 5 Hz stimulation activates noxious transmission mediated mainly through C fibers. Although 250 Hz stimulation activates both Aδ and Aβ fibers, tactile sensation would not be perceived when painful sensation is produced at the same time. Therefore, 250 Hz was effective stimulus frequency for activation of Aδ fibers initiating noxious sensation. Thus, the transcutaneous sine-wave stimulation can be applied to evaluate functional changes of sensory transmission by comparing thresholds with the three

  7. Frequency specific modulation of human somatosensory cortex

    Directory of Open Access Journals (Sweden)

    Matteo eFeurra

    2011-02-01

    Full Text Available Oscillatory neuronal activities are commonly observed in response to sensory stimulation. However, their functional roles are still the subject of debate. One way to probe the roles of oscillatory neural activities is to deliver alternating current to the cortex at biologically relevant frequencies and examine whether such stimulation influences perception and cognition. In this study, we tested whether transcranial alternating current stimulation (tACS over the primary somatosensory cortex (SI could elicit tactile sensations in humans in a frequency dependent manner. We tested the effectiveness of tACS over SI at frequency bands ranging from 2 to 70 Hz. Our results show that stimulation in alpha (10-14 Hz and high gamma (52-70 Hz frequency range produces a tactile sensation in the contralateral hand. A weaker effect was also observed for beta (16-20 Hz stimulation. These findings highlight the frequency-dependency of effective tACS over SI with the effective frequencies corresponding to those observed in previous EEG/MEG studies of tactile perception. Our present study suggests that tACS could be used as a powerful online stimulation technique to reveal the causal roles of oscillatory brain activities.

  8. Communication calls produced by electrical stimulation of four structures in the guinea pig brain

    Science.gov (United States)

    Green, David B.; Shackleton, Trevor M.; Grimsley, Jasmine M. S.; Zobay, Oliver; Palmer, Alan R.

    2018-01-01

    One of the main central processes affecting the cortical representation of conspecific vocalizations is the collateral output from the extended motor system for call generation. Before starting to study this interaction we sought to compare the characteristics of calls produced by stimulating four different parts of the brain in guinea pigs (Cavia porcellus). By using anaesthetised animals we were able to reposition electrodes without distressing the animals. Trains of 100 electrical pulses were used to stimulate the midbrain periaqueductal grey (PAG), hypothalamus, amygdala, and anterior cingulate cortex (ACC). Each structure produced a similar range of calls, but in significantly different proportions. Two of the spontaneous calls (chirrup and purr) were never produced by electrical stimulation and although we identified versions of chutter, durr and tooth chatter, they differed significantly from our natural call templates. However, we were routinely able to elicit seven other identifiable calls. All seven calls were produced both during the 1.6 s period of stimulation and subsequently in a period which could last for more than a minute. A single stimulation site could produce four or five different calls, but the amygdala was much less likely to produce a scream, whistle or rising whistle than any of the other structures. These three high-frequency calls were more likely to be produced by females than males. There were also differences in the timing of the call production with the amygdala primarily producing calls during the electrical stimulation and the hypothalamus mainly producing calls after the electrical stimulation. For all four structures a significantly higher stimulation current was required in males than females. We conclude that all four structures can be stimulated to produce fictive vocalizations that should be useful in studying the relationship between the vocal motor system and cortical sensory representation. PMID:29584746

  9. Communication calls produced by electrical stimulation of four structures in the guinea pig brain.

    Directory of Open Access Journals (Sweden)

    David B Green

    Full Text Available One of the main central processes affecting the cortical representation of conspecific vocalizations is the collateral output from the extended motor system for call generation. Before starting to study this interaction we sought to compare the characteristics of calls produced by stimulating four different parts of the brain in guinea pigs (Cavia porcellus. By using anaesthetised animals we were able to reposition electrodes without distressing the animals. Trains of 100 electrical pulses were used to stimulate the midbrain periaqueductal grey (PAG, hypothalamus, amygdala, and anterior cingulate cortex (ACC. Each structure produced a similar range of calls, but in significantly different proportions. Two of the spontaneous calls (chirrup and purr were never produced by electrical stimulation and although we identified versions of chutter, durr and tooth chatter, they differed significantly from our natural call templates. However, we were routinely able to elicit seven other identifiable calls. All seven calls were produced both during the 1.6 s period of stimulation and subsequently in a period which could last for more than a minute. A single stimulation site could produce four or five different calls, but the amygdala was much less likely to produce a scream, whistle or rising whistle than any of the other structures. These three high-frequency calls were more likely to be produced by females than males. There were also differences in the timing of the call production with the amygdala primarily producing calls during the electrical stimulation and the hypothalamus mainly producing calls after the electrical stimulation. For all four structures a significantly higher stimulation current was required in males than females. We conclude that all four structures can be stimulated to produce fictive vocalizations that should be useful in studying the relationship between the vocal motor system and cortical sensory representation.

  10. Communication calls produced by electrical stimulation of four structures in the guinea pig brain.

    Science.gov (United States)

    Green, David B; Shackleton, Trevor M; Grimsley, Jasmine M S; Zobay, Oliver; Palmer, Alan R; Wallace, Mark N

    2018-01-01

    One of the main central processes affecting the cortical representation of conspecific vocalizations is the collateral output from the extended motor system for call generation. Before starting to study this interaction we sought to compare the characteristics of calls produced by stimulating four different parts of the brain in guinea pigs (Cavia porcellus). By using anaesthetised animals we were able to reposition electrodes without distressing the animals. Trains of 100 electrical pulses were used to stimulate the midbrain periaqueductal grey (PAG), hypothalamus, amygdala, and anterior cingulate cortex (ACC). Each structure produced a similar range of calls, but in significantly different proportions. Two of the spontaneous calls (chirrup and purr) were never produced by electrical stimulation and although we identified versions of chutter, durr and tooth chatter, they differed significantly from our natural call templates. However, we were routinely able to elicit seven other identifiable calls. All seven calls were produced both during the 1.6 s period of stimulation and subsequently in a period which could last for more than a minute. A single stimulation site could produce four or five different calls, but the amygdala was much less likely to produce a scream, whistle or rising whistle than any of the other structures. These three high-frequency calls were more likely to be produced by females than males. There were also differences in the timing of the call production with the amygdala primarily producing calls during the electrical stimulation and the hypothalamus mainly producing calls after the electrical stimulation. For all four structures a significantly higher stimulation current was required in males than females. We conclude that all four structures can be stimulated to produce fictive vocalizations that should be useful in studying the relationship between the vocal motor system and cortical sensory representation.

  11. Transcranial magnetic stimulation in schizophrenia.

    Science.gov (United States)

    Zaman, Rashid; Thind, Dilraj; Kocmur, Marga

    2008-11-01

    Transcranial magnetic stimulation (TMS) is a non-invasive and painless way of stimulating the neural tissue (cerebral cortex, spinal roots, and cranial and peripheral nerves). The first attempts at stimulating the neural tissue date back to 1896 by d'Arsonval; however, it was successfully carried out by Barker and colleagues in Sheffield, UK, in 1985. It soon became a useful tool in neuroscience for neurophysiologists and neurologists and psychiatrists. The original single-pulse TMS, largely used as an investigative tool, was further refined and developed in the early 1990s into what is known as repetitive TMS (rTMS), having a frequency range of 1-60 Hz. The stimulation by both TMS and rTMS of various cortical regions displayed alteration of movement, mood, and behavior, leading researchers to investigate a number of psychiatric and neuropsychiatric disorders, as well as to explore its therapeutic potential. There is now a large amount of literature on the use of TMS/rTMS in depression; however, its use in schizophrenia, both as an investigative and certainly as a therapeutic tool is relatively recent with a limited but increasing number of publications. In this article, we will outline the principles of TMS/rTMS and critically review their use in schizophrenia both as investigative and potential therapeutic tools.

  12. Cardiac effects produced by long-term stimulation of thoracic autonomic ganglia or nerves: implications for interneuronal interactions within the thoracic autonomic nervous system.

    Science.gov (United States)

    Butler, C; Watson-Wright, W M; Wilkinson, M; Johnstone, D E; Armour, J A

    1988-03-01

    -term stimulation in intrathoracic sympathetic neural elements with frequencies as low as 2 Hz may augment the heart as much as higher stimulation frequencies, depending upon the structure stimulated and the cardiovascular parameter monitored.

  13. Bursting behaviours in cascaded stimulated Brillouin scattering

    International Nuclear Information System (INIS)

    Liu Zhan-Jun; He Xian-Tu; Zheng Chun-Yang; Wang Yu-Gang

    2012-01-01

    Stimulated Brillouin scattering is studied by numerically solving the Vlasov—Maxwell system. A cascade of stimulated Brillouin scattering can occur when a linearly polarized laser pulse propagates in a plasma. It is found that a stimulated Brillouin scattering cascade can reduce the scattering and increase the transmission of light, as well as introduce a bursting behaviour in the evolution of the laser-plasma interaction. The bursting time in the reflectivity is found to be less than half the ion acoustic period. The ion temperature can affect the stimulated Brillouin scattering cascade, which can repeat several times at low ion temperatures and can be completely eliminated at high ion temperatures. For stimulated Brillouin scattering saturation, higher-harmonic generation and wave—wave interaction of the excited ion acoustic waves can restrict the amplitude of the latter. In addition, stimulated Brillouin scattering cascade can restrict the amplitude of the scattered light. (physics of gases, plasmas, and electric discharges)

  14. Spinal cord stimulation

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007560.htm Spinal cord stimulation To use the sharing features on this page, please enable JavaScript. Spinal cord stimulation is a treatment for pain that uses ...

  15. Feldspar, Infrared Stimulated Luminescence

    DEFF Research Database (Denmark)

    Jain, Mayank

    2014-01-01

    This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

  16. Growth hormone stimulation test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003377.htm Growth hormone stimulation test To use the sharing features on this page, please enable JavaScript. The growth hormone (GH) stimulation test measures the ability of ...

  17. Assessment of the risk of fall, related to visual stimulation, in patients with central vestibular disorders.

    Science.gov (United States)

    Suárez, H; Musé, P; Suárez, A; Arocena, M

    2001-01-01

    In order to assess the influence of visual stimulation in the triggering of imbalance and falls in the elderly population, the postural responses of 18 elderly patients with central vestibular disorders and clinical evidence of instability and falls were studied while receiving different types of visual stimuli. The stimulation conditions were: (i) no specific stimuli; (ii) smooth pursuit with pure sinusoids of 0.2 Hz as foveal stimulation; and (iii) optokinetic stimulation (OK) as retinal stimuli. Using a platform AMTI Accusway platform, the 95% confidence ellipse (CE) and sway velocity (SV) were evaluated with a scalogram using wavelets in order to assess the relationship between time and frequency in postural control. Velocity histograms were also constructed in order to observe the distribution of velocity values during the recording. A non-homogeneous postural behavior after visual stimulation was found among this population. In five of the patients the OK stimulation generated: (i) significantly higher average values of CE ( > 3.4+/-0.69 cm2); (ii) a significant increase in the average values of the SV ( > 3.89+/-1.15 cm/s) and a velocity histogram with a homogeneous distribution between 0 and 18 cm/s; and (iii) a scalogram with sway frequencies of up to 4 Hz distributed in both the X and Y directions (backwards and forwards and lateral) during visual stimulation with arbitrary units of energy density > 5. These three qualitative and quantitative aspects could be "markers" of visual dependence in the triggering of the mechanism of lack of equilibrium and hence falls in some elderly patients and should be considered in order to prevent falls and also to assist in the rehabilitation program of these patients.

  18. Towards a Switched-Capacitor Based Stimulator for Efficient Deep-Brain Stimulation

    Science.gov (United States)

    Vidal, Jose; Ghovanloo, Maysam

    2013-01-01

    We have developed a novel 4-channel prototype stimulation circuit for implantable neurological stimulators (INS). This Switched-Capacitor based Stimulator (SCS) aims to utilize charge storage and charge injection techniques to take advantage of both the efficiency of conventional voltage-controlled stimulators (VCS) and the safety and controllability of current-controlled stimulators (CCS). The discrete SCS prototype offers fine control over stimulation parameters such as voltage, current, pulse width, frequency, and active electrode channel via a LabVIEW graphical user interface (GUI) when connected to a PC through USB. Furthermore, the prototype utilizes a floating current sensor to provide charge-balanced biphasic stimulation and ensure safety. The stimulator was analyzed using an electrode-electrolyte interface (EEI) model as well as with a pair of pacing electrodes in saline. The primary motivation of this research is to test the feasibility and functionality of a safe, effective, and power-efficient switched-capacitor based stimulator for use in Deep Brain Stimulation. PMID:21095987

  19. Computational analysis of transcranial magnetic stimulation in the presence of deep brain stimulation probes

    Science.gov (United States)

    Syeda, F.; Holloway, K.; El-Gendy, A. A.; Hadimani, R. L.

    2017-05-01

    Transcranial Magnetic Stimulation is an emerging non-invasive treatment for depression, Parkinson's disease, and a variety of other neurological disorders. Many Parkinson's patients receive the treatment known as Deep Brain Stimulation, but often require additional therapy for speech and swallowing impairment. Transcranial Magnetic Stimulation has been explored as a possible treatment by stimulating the mouth motor area of the brain. We have calculated induced electric field, magnetic field, and temperature distributions in the brain using finite element analysis and anatomically realistic heterogeneous head models fitted with Deep Brain Stimulation leads. A Figure of 8 coil, current of 5000 A, and frequency of 2.5 kHz are used as simulation parameters. Results suggest that Deep Brain Stimulation leads cause surrounding tissues to experience slightly increased E-field (Δ Emax =30 V/m), but not exceeding the nominal values induced in brain tissue by Transcranial Magnetic Stimulation without leads (215 V/m). The maximum temperature in the brain tissues surrounding leads did not change significantly from the normal human body temperature of 37 °C. Therefore, we ascertain that Transcranial Magnetic Stimulation in the mouth motor area may stimulate brain tissue surrounding Deep Brain Stimulation leads, but will not cause tissue damage.

  20. Frequency spirals

    International Nuclear Information System (INIS)

    Ottino-Löffler, Bertrand; Strogatz, Steven H.

    2016-01-01

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  1. Frequency spirals

    Energy Technology Data Exchange (ETDEWEB)

    Ottino-Löffler, Bertrand; Strogatz, Steven H., E-mail: strogatz@cornell.edu [Center for Applied Mathematics, Cornell University, Ithaca, New York 14853 (United States)

    2016-09-15

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  2. Pudendal nerve stimulation and block by a wireless-controlled implantable stimulator in cats.

    Science.gov (United States)

    Yang, Guangning; Wang, Jicheng; Shen, Bing; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2014-07-01

    The study aims to determine the functionality of a wireless-controlled implantable stimulator designed for stimulation and block of the pudendal nerve. In five cats under α-chloralose anesthesia, the stimulator was implanted underneath the skin on the left side in the lower back along the sacral spine. Two tripolar cuff electrodes were implanted bilaterally on the pudendal nerves in addition to one bipolar cuff electrode that was implanted on the left side central to the tripolar cuff electrode. The stimulator provided high-frequency (5-20 kHz) biphasic stimulation waveforms to the two tripolar electrodes and low-frequency (1-100 Hz) rectangular pulses to the bipolar electrode. Bladder and urethral pressures were measured to determine the effects of pudendal nerve stimulation (PNS) or block. The maximal (70-100 cmH2O) urethral pressure generated by 20-Hz PNS applied via the bipolar electrode was completely eliminated by the pudendal nerve block induced by the high-frequency stimulation (6-15 kHz, 6-10 V) applied via the two tripolar electrodes. In a partially filled bladder, 20-30 Hz PNS (2-8 V, 0.2 ms) but not 5 Hz stimulation applied via the bipolar electrode elicited a large sustained bladder contraction (45.9 ± 13.4 to 52.0 ± 22 cmH2O). During cystometry, the 5 Hz PNS significantly (p < 0.05) increased bladder capacity to 176.5 ± 27.1% of control capacity. The wireless-controlled implantable stimulator successfully generated the required waveforms for stimulation and block of pudendal nerve, which will be useful for restoring bladder functions after spinal cord injury. © 2013 International Neuromodulation Society.

  3. In vitro magnetic stimulation: a simple stimulation device to deliver defined low intensity electromagnetic fields

    Directory of Open Access Journals (Sweden)

    Stephanie Grehl

    2016-11-01

    Full Text Available Non-invasive electromagnetic field brain stimulation (NIBS appears to benefit human neurological and psychiatric conditions, although the optimal stimulation parameters and underlying mechanisms remain unclear. Although in vitro studies have begun to elucidate cellular mechanisms, stimulation is delivered by a range of coils (from commercially available human stimulation coils to laboratory-built circuits so that the electromagnetic fields induced within the tissue to produce the reported effects are ill-defined.Here we develop a simple in vitro stimulation device with plug-and-play features that allow delivery of a range of stimulation parameters. We chose to test low intensity repetitive magnetic stimulation (LI-rMS delivered at 3 frequencies to hindbrain explant cultures containing the olivocerebellar pathway. We used computational modelling to define the parameters of a stimulation circuit and coil that deliver a unidirectional homogeneous magnetic field of known intensity and direction, and therefore a predictable electric field, to the target. We built the coil to be compatible with culture requirements: stimulation within an incubator; a flat surface allowing consistent position and magnetic field direction; location outside the culture plate to maintain sterility and no heating or vibration. Measurements at the explant confirmed the induced magnetic field was homogenous and matched the simulation results. To validate our system we investigated biological effects following LI-rMS at 1 Hz, 10 Hz and biomimetic high frequency (BHFS, which we have previously shown induces neural circuit reorganisation. We found that gene expression was modified by LI-rMS in a frequency-related manner. Four hours after a single 10-minute stimulation session, the number of c-fos positive cells increased, indicating that our stimulation activated the tissue. Also, after 14 days of LI-rMS, the expression of genes normally present in the tissue was differentially

  4. Frequency-specific corticofugal modulation of the dorsal cochlear nucleus in mice.

    Science.gov (United States)

    Kong, Lingzhi; Xiong, Colin; Li, Liang; Yan, Jun

    2014-01-01

    The primary auditory cortex (AI) modulates the sound information processing in the lemniscal subcortical nuclei, including the anteroventral cochlear nucleus (AVCN), in a frequency-specific manner. The dorsal cochlear nucleus (DCN) is a non-lemniscal subcortical nucleus but it is tonotopically organized like the AVCN. However, it remains unclear how the AI modulates the sound information processing in the DCN. This study examined the impact of focal electrical stimulation of AI on the auditory responses of the DCN neurons in mice. We found that the electrical stimulation induced significant changes in the best frequency (BF) of DCN neurons. The changes in the BFs were highly specific to the BF differences between the stimulated AI neurons and the recorded DCN neurons. The DCN BFs shifted higher when the AI BFs were higher than the DCN BFs and the DCN BFs shifted lower when the AI BFs were lower than the DCN BFs. The DCN BFs showed no change when the AI and DCN BFs were similar. Moreover, the BF shifts were linearly correlated to the BF differences. Thus, our data suggest that corticofugal modulation of the DCN is also highly specific to frequency information, similar to the corticofugal modulation of the AVCN. The frequency-specificity of corticofugal modulation does not appear limited to the lemniscal ascending pathway.

  5. Single-transducer dual-frequency ultrasound generation to enhance acoustic cavitation.

    Science.gov (United States)

    Liu, Hao-Li; Hsieh, Chao-Ming

    2009-03-01

    Dual- or multiple-frequency ultrasound stimulation is capable of effectively enhancing the acoustic cavitation effect over single-frequency ultrasound. Potential application of this sonoreactor design has been widely proposed such as on sonoluminescence, sonochemistry enhancement, and transdermal drug release enhancement. All currently available sonoreactor designs employed multiple piezoelectric transducers for generating single-frequency ultrasonic waves separately and then these waves were mixed and interfered in solutions. The purpose of this research is to propose a novel design of generating dual-frequency ultrasonic waves with single piezoelectric elements, thereby enhancing acoustic cavitation. Macroscopic bubbles were detected optically, and they were quantified at either a single-frequency or for different frequency combinations for determining their efficiency for enhancing acoustic cavitation. Visible bubbles were optically detected and hydrogen peroxide was measured to quantify acoustic cavitation. Test water samples with different gas concentrations and different power levels were used to determine the efficacy of enhancing acoustic cavitation of this design. The spectrum obtained from the backscattered signals was also recorded and examined to confirm the occurrence of stable cavitation. The results confirmed that single-element dual-frequency ultrasound stimulation can enhance acoustic cavitation. Under certain testing conditions, the generation of bubbles can be enhanced up to a level of five times higher than the generation of bubbles in single-frequency stimulation, and can increase the hydrogen peroxide production up to an increase of one fold. This design may serve as a useful alternative for future sonoreactor design owing to its simplicity to produce dual- or multiple-frequency ultrasound.

  6. Effects of Acute Sacral Neuromodulation at Different Frequencies on Bladder Overactivity in Pigs

    Directory of Open Access Journals (Sweden)

    Xing Li

    2017-06-01

    Full Text Available Purpose We investigated the effects of different stimulation frequencies on the inhibition of bladder overactivity by sacral neuromodulation (SNM in pigs. Methods Implant-driven stimulators were used to stimulate the S3 spinal nerve in 13 pigs. Cystometry was performed by infusing normal saline (NS or acetic acid (AA. SNM (pulse width, 210 µsec at frequencies ranging from 5 to 50 Hz was conducted at the intensity threshold at which observable perianal and/or tail movement was induced. Multiple cystometrograms were performed to determine the effects of different frequencies on the micturition reflex. Results AA-induced bladder overactivity significantly reduced the bladder capacity (BC to 34.4%±4.7% of the NS control level (354.4±35.9 mL (P0.05, but SNM at 15, 30, and 50 Hz significantly increased the BC to 54.5%±7.1%, 55.2%±6.5%, and 57.2%±6.1% of the NS control level (P0.05. Conclusions This study demonstrated that 15 Hz was an appropriate frequency for SNM and that frequencies higher than 15 Hz did not lead to better surgical outcomes.

  7. Effect of Electrical Current Stimulation on Pseudomonas Aeruginosa Growth

    Science.gov (United States)

    Alneami, Auns Q.; Khalil, Eman G.; Mohsien, Rana A.; Albeldawi, Ali F.

    2018-05-01

    The present study evaluates the effect of electrical current with different frequencies stimulation to kill pathogenic Pseudomonas aeruginosa (PA) bacteria in vitro using human safe level of electricity controlled by function generator. A wide range of frequencies has been used from 0.5 Hz-1.2 MHz to stimulate the bacteria at a voltage of 20 p-p volt for different periods of time (5 to 30) minutes. The culture of bacteria used Nickel, Nichrome, or Titanium electrode using agarose in phosphate buffer saline (PBS) and mixed with bacterial stock activated by trypticase soy broth (TSB). The results of frequencies between 0.5-1 KHz show the inhibition zone diameter of 20 mm in average at 30 minutes of stimulation. At frequencies between 3-60 KHz the inhibition zone diameter was only 10mm for 30 minutes of stimulation. While the average of inhibition zone diameter increased to more than 30mm for 30 minutes of stimulation at frequencies between 80-120 KHz. From this study we conclude that at specific frequency (resonance frequency) (frequencies between 0.5-1 KHz) there was relatively large inhibition zone because the inductive reactance effect is equal to the value of capacitive reactance effect (XC = XL). At frequencies over than 60 KHz, maximum inhibition zone noticed because the capacitance impedance becomes negligible (only the small resistivity of the bacterial internal organs).

  8. Spinal Cord Stimulation: Clinical Efficacy and Potential Mechanisms.

    Science.gov (United States)

    Sdrulla, Andrei D; Guan, Yun; Raja, Srinivasa N

    2018-03-11

    Spinal cord stimulation (SCS) is a minimally invasive therapy used for the treatment of chronic neuropathic pain. SCS is a safe and effective alternative to medications such as opioids, and multiple randomized controlled studies have demonstrated efficacy for difficult-to-treat neuropathic conditions such as failed back surgery syndrome. Conventional SCS is believed mediate pain relief via activation of dorsal column Aβ fibers, resulting in variable effects on sensory and pain thresholds, and measurable alterations in higher order cortical processing. Although potentiation of inhibition, as suggested by Wall and Melzack's gate control theory, continues to be the leading explanatory model, other segmental and supraspinal mechanisms have been described. Novel, non-standard, stimulation waveforms such as high-frequency and burst have been shown in some studies to be clinically superior to conventional SCS, however their mechanisms of action remain to be determined. Additional studies are needed, both mechanistic and clinical, to better understand optimal stimulation strategies for different neuropathic conditions, improve patient selection and optimize efficacy. © 2018 World Institute of Pain.

  9. Effects of Vibrotactile Stimulation During Virtual Sandboarding

    DEFF Research Database (Denmark)

    Lind, Stine; Thomsen, Lui; Egebjerg, Mie

    2016-01-01

    This poster details a within-subjects study (n=17) investigating the effects of vibrotactile stimulation on illusory self-motion, presence and perceived realism during an interactive sandboarding simulation. Vibrotactile feedback was delivered using a low frequency audio transducer mounted undern...

  10. Algorithmic design of a noise-resistant and efficient closed-loop deep brain stimulation system: A computational approach.

    Directory of Open Access Journals (Sweden)

    Sofia D Karamintziou

    Full Text Available Advances in the field of closed-loop neuromodulation call for analysis and modeling approaches capable of confronting challenges related to the complex neuronal response to stimulation and the presence of strong internal and measurement noise in neural recordings. Here we elaborate on the algorithmic aspects of a noise-resistant closed-loop subthalamic nucleus deep brain stimulation system for advanced Parkinson's disease and treatment-refractory obsessive-compulsive disorder, ensuring remarkable performance in terms of both efficiency and selectivity of stimulation, as well as in terms of computational speed. First, we propose an efficient method drawn from dynamical systems theory, for the reliable assessment of significant nonlinear coupling between beta and high-frequency subthalamic neuronal activity, as a biomarker for feedback control. Further, we present a model-based strategy through which optimal parameters of stimulation for minimum energy desynchronizing control of neuronal activity are being identified. The strategy integrates stochastic modeling and derivative-free optimization of neural dynamics based on quadratic modeling. On the basis of numerical simulations, we demonstrate the potential of the presented modeling approach to identify, at a relatively low computational cost, stimulation settings potentially associated with a significantly higher degree of efficiency and selectivity compared with stimulation settings determined post-operatively. Our data reinforce the hypothesis that model-based control strategies are crucial for the design of novel stimulation protocols at the backstage of clinical applications.

  11. Algorithmic design of a noise-resistant and efficient closed-loop deep brain stimulation system: A computational approach.

    Science.gov (United States)

    Karamintziou, Sofia D; Custódio, Ana Luísa; Piallat, Brigitte; Polosan, Mircea; Chabardès, Stéphan; Stathis, Pantelis G; Tagaris, George A; Sakas, Damianos E; Polychronaki, Georgia E; Tsirogiannis, George L; David, Olivier; Nikita, Konstantina S

    2017-01-01

    Advances in the field of closed-loop neuromodulation call for analysis and modeling approaches capable of confronting challenges related to the complex neuronal response to stimulation and the presence of strong internal and measurement noise in neural recordings. Here we elaborate on the algorithmic aspects of a noise-resistant closed-loop subthalamic nucleus deep brain stimulation system for advanced Parkinson's disease and treatment-refractory obsessive-compulsive disorder, ensuring remarkable performance in terms of both efficiency and selectivity of stimulation, as well as in terms of computational speed. First, we propose an efficient method drawn from dynamical systems theory, for the reliable assessment of significant nonlinear coupling between beta and high-frequency subthalamic neuronal activity, as a biomarker for feedback control. Further, we present a model-based strategy through which optimal parameters of stimulation for minimum energy desynchronizing control of neuronal activity are being identified. The strategy integrates stochastic modeling and derivative-free optimization of neural dynamics based on quadratic modeling. On the basis of numerical simulations, we demonstrate the potential of the presented modeling approach to identify, at a relatively low computational cost, stimulation settings potentially associated with a significantly higher degree of efficiency and selectivity compared with stimulation settings determined post-operatively. Our data reinforce the hypothesis that model-based control strategies are crucial for the design of novel stimulation protocols at the backstage of clinical applications.

  12. Stimulating at the right time: phase-specific deep brain stimulation.

    Science.gov (United States)

    Cagnan, Hayriye; Pedrosa, David; Little, Simon; Pogosyan, Alek; Cheeran, Binith; Aziz, Tipu; Green, Alexander; Fitzgerald, James; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Friston, Karl J; Denison, Timothy; Brown, Peter

    2017-01-01

    SEE MOLL AND ENGEL DOI101093/AWW308 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Brain regions dynamically engage and disengage with one another to execute everyday actions from movement to decision making. Pathologies such as Parkinson's disease and tremor emerge when brain regions controlling movement cannot readily decouple, compromising motor function. Here, we propose a novel stimulation strategy that selectively regulates neural synchrony through phase-specific stimulation. We demonstrate for the first time the therapeutic potential of such a stimulation strategy for the treatment of patients with pathological tremor. Symptom suppression is achieved by delivering stimulation to the ventrolateral thalamus, timed according to the patient's tremor rhythm. Sustained locking of deep brain stimulation to a particular phase of tremor afforded clinically significant tremor relief (up to 87% tremor suppression) in selected patients with essential tremor despite delivering less than half the energy of conventional high frequency stimulation. Phase-specific stimulation efficacy depended on the resonant characteristics of the underlying tremor network. Selective regulation of neural synchrony through phase-locked stimulation has the potential to both increase the efficiency of therapy and to minimize stimulation-induced side effects. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain.

  13. Molybdenum coated SU-8 microneedle electrodes for transcutaneous electrical nerve stimulation.

    Science.gov (United States)

    Soltanzadeh, Ramin; Afsharipour, Elnaz; Shafai, Cyrus; Anssari, Neda; Mansouri, Behzad; Moussavi, Zahra

    2017-11-21

    Electrophysiological devices are connected to the body through electrodes. In some applications, such as nerve stimulation, it is needed to minimally pierce the skin and reach the underneath layers to bypass the impedance of the first layer called stratum corneum. In this study, we have designed and fabricated surface microneedle electrodes for applications such as electrical peripheral nerve stimulation. We used molybdenum for microneedle fabrication, which is a biocompatible metal; it was used for the conductive layer of the needle array. To evaluate the performance of the fabricated electrodes, they were compared with the conventional surface electrodes in nerve conduction velocity experiment. The recorded signals showed a much lower contact resistance and higher bandwidth in low frequencies for the fabricated microneedle electrodes compared to those of the conventional electrodes. These results indicate the electrode-tissue interface capacitance and charge transfer resistance have been increased in our designed electrodes, while the contact resistance decreased. These changes will lead to less harmful Faradaic current passing through the tissue during stimulation in different frequencies. We also compared the designed microneedle electrodes with conventional ones by a 3-dimensional finite element simulation. The results demonstrated that the current density in the deep layers of the skin and the directivity toward a target nerve for microneedle electrodes were much more than those for the conventional ones. Therefore, the designed electrodes are much more efficient than the conventional electrodes for superficial transcutaneous nerve stimulation purposes.

  14. Effects of Navigated Repetitive Transcranial Magnetic Stimulation After Stroke.

    Science.gov (United States)

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

    2018-03-01

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

  15. A wireless wearable surface functional electrical stimulator

    Science.gov (United States)

    Wang, Hai-Peng; Guo, Ai-Wen; Zhou, Yu-Xuan; Xia, Yang; Huang, Jia; Xu, Chong-Yao; Huang, Zong-Hao; Lü, Xiao-Ying; Wang, Zhi-Gong

    2017-09-01

    In this paper, a wireless wearable functional electrical stimulator controlled by Android phone with real-time-varying stimulation parameters for multichannel surface functional electrical stimulation application has been developed. It can help post-stroke patients using more conveniently. This study focuses on the prototype design, including the specific wristband concept, circuits and stimulation pulse-generation algorithm. A novel stimulator circuit with a driving stage using a complementary current source technique is proposed to achieve a high-voltage compliance, a large output impedance and an accurate linear voltage-to-current conversion. The size of the prototype has been significantly decreased to 17 × 7.5 × 1 cm3. The performance of the prototype has been tested with a loaded resistor and wrist extension/flexion movement of three hemiplegic patients. According to the experiments, the stimulator can generate four-channel charge-balanced biphasic stimulation with a voltage amplitude up to 60 V, and the pulse frequency and width can be adjusted in real time with a range of 100-600 μs and 20-80 Hz, respectively.

  16. Stimulation of phagocytosis by sulforaphane

    International Nuclear Information System (INIS)

    Suganuma, Hiroyuki; Fahey, Jed W.; Bryan, Kelley E.; Healy, Zachary R.; Talalay, Paul

    2011-01-01

    Research highlights: → Sulforaphane stimulates the phagocytosis of RAW 264.7 macrophages under conditions of serum deprivation. → This effect does not require Nrf2-dependent induction of phase 2 genes. → Inactivation of macrophage migration inhibitory factor (MIF) by sulforaphane may be involved in stimulation of phagocytosis by sulforaphane. -- Abstract: Sulforaphane, a major isothiocyanate derived from cruciferous vegetables, protects living systems against electrophile toxicity, oxidative stress, inflammation, and radiation. A major protective mechanism is the induction of a network of endogenous cytoprotective (phase 2) genes that are regulated by transcription factor Nrf2. To obtain a more detailed understanding of the anti-inflammatory and immunomodulatory effects of sulforaphane, we evaluated its effect on the phagocytosis activity of RAW 264.7 murine macrophage-like cells by measuring the uptake of 2-μm diameter polystyrene beads. Sulforaphane raised the phagocytosis activity of RAW 264.7 cells but only in the absence or presence of low concentrations (1%) of fetal bovine serum. Higher serum concentrations depressed phagocytosis and abolished its stimulation by sulforaphane. This stimulation did not depend on the induction of Nrf2-regulated genes since it occurred in peritoneal macrophages of nrf2 -/- mice. Moreover, a potent triterpenoid inducer of Nrf2-dependent genes did not stimulate phagocytosis, whereas sulforaphane and another isothiocyanate (benzyl isothiocyanate) had comparable inducer potencies. It has been shown recently that sulforaphane is a potent and direct inactivator of macrophage migration inhibitory factor (MIF), an inflammatory cytokine. Moreover, the addition of recombinant MIF to RAW 264.7 cells attenuated phagocytosis, but sulforaphane-inactivated MIF did not affect phagocytosis. The inactivation of MIF may therefore be involved in the phagocytosis-enhancing activity of sulforaphane.

  17. Stimulation of phagocytosis by sulforaphane

    Energy Technology Data Exchange (ETDEWEB)

    Suganuma, Hiroyuki, E-mail: hsuganu1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Fahey, Jed W., E-mail: jfahey@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Bryan, Kelley E., E-mail: kbryanm1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Healy, Zachary R., E-mail: zhealy1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Talalay, Paul, E-mail: ptalalay@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States)

    2011-02-04

    Research highlights: {yields} Sulforaphane stimulates the phagocytosis of RAW 264.7 macrophages under conditions of serum deprivation. {yields} This effect does not require Nrf2-dependent induction of phase 2 genes. {yields} Inactivation of macrophage migration inhibitory factor (MIF) by sulforaphane may be involved in stimulation of phagocytosis by sulforaphane. -- Abstract: Sulforaphane, a major isothiocyanate derived from cruciferous vegetables, protects living systems against electrophile toxicity, oxidative stress, inflammation, and radiation. A major protective mechanism is the induction of a network of endogenous cytoprotective (phase 2) genes that are regulated by transcription factor Nrf2. To obtain a more detailed understanding of the anti-inflammatory and immunomodulatory effects of sulforaphane, we evaluated its effect on the phagocytosis activity of RAW 264.7 murine macrophage-like cells by measuring the uptake of 2-{mu}m diameter polystyrene beads. Sulforaphane raised the phagocytosis activity of RAW 264.7 cells but only in the absence or presence of low concentrations (1%) of fetal bovine serum. Higher serum concentrations depressed phagocytosis and abolished its stimulation by sulforaphane. This stimulation did not depend on the induction of Nrf2-regulated genes since it occurred in peritoneal macrophages of nrf2{sup -/-} mice. Moreover, a potent triterpenoid inducer of Nrf2-dependent genes did not stimulate phagocytosis, whereas sulforaphane and another isothiocyanate (benzyl isothiocyanate) had comparable inducer potencies. It has been shown recently that sulforaphane is a potent and direct inactivator of macrophage migration inhibitory factor (MIF), an inflammatory cytokine. Moreover, the addition of recombinant MIF to RAW 264.7 cells attenuated phagocytosis, but sulforaphane-inactivated MIF did not affect phagocytosis. The inactivation of MIF may therefore be involved in the phagocytosis-enhancing activity of sulforaphane.

  18. Major enhancement of extra-low-frequency radiation by increasing the high-frequency heating wave power in electrojet modulation

    International Nuclear Information System (INIS)

    Kuo, S.P.; Lee, S.H.; Kossey, Paul

    2002-01-01

    Extra-low-frequency (ELF) wave generation by modulated polar electrojet currents is studied. The amplitude-modulated high-frequency (HF) heating wave excites a stimulated thermal instability to enhance the electrojet current modulation by the passive Ohmic heating process. Inelastic collisions of electrons with neutral particles (mainly due to vibrational excitation of N 2 ) damp nonlinearly this instability, which is normally saturated at low levels. However, the electron's inelastic collision loss rate drops rapidly to a low value in the energy regime from 3.5 to 6 eV. As the power of the modulated HF heating wave exceeds a threshold level, it is shown that significant electron heating enhanced by the stimulated thermal instability can indeed cause a steep drop in the electron inelastic collision loss rate. Consequently, this instability saturates at a much higher level, resulting to a near step increase (of about 10-13 dB, depending on the modulation wave form) in the spectral intensity of ELF radiation. The dependence of the threshold power of the HF heating wave on the modulation frequency is determined

  19. Stimulation of plasma waves by electron guns on the ISEE-1 satellite

    Science.gov (United States)

    Lebreton, J.-P.; Torbert, R.; Anderson, R.; Harvey, C.

    1982-01-01

    The results of the ISEE-1 satellite experiment relating to observations of the waves stimulated during electron injections, when the spacecraft is passing through the magnetosphere, the magnetosheath, and the solar wind, are discussed. It is shown that the injection of an electron beam current of the order of 10 to 60 microamperes with energies ranging from 0 to 40 eV produces enhancements in the electric wave spectrum. An attempt has been made to identify the low-frequency electrostatic wave observed below the ion plasma frequency as an ion acoustic mode, although the excitation mechanism is not clear. A coupling mechanism between the electron plasma mode and streaming electrons with energies higher than the thermal speed of the cold electron population has been proposed to explain the observations above the electron plasma frequency.

  20. Stimulation of plasma waves by electron guns on the ISEE-1 satellite

    International Nuclear Information System (INIS)

    Lebreton, J.P.; Torbert, R.; Anderson, R.; Harvey, C.

    1982-01-01

    The results of the ISEE-1 satellite experiment relating to observations of the waves stimulated during electron injections, when the spacecraft is passing through the magnetosphere, the magnetosheath, and the solar wind, are discussed. It is shown that the injection of an electron beam current of the order of 10 to 60 microamperes with energies ranging from 0 to 40 eV produces enhancements in the electric wave spectrum. An attempt has been made to identify the low-frequency electrostatic wave observed below the ion plasma frequency as an ion acoustic mode, although the excitation mechanism is not clear. A coupling mechanism between the electron plasma mode and streaming electrons with energies higher than the thermal speed of the cold electron population has been proposed to explain the observations above the electron plasma frequency. 9 references

  1. [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.

  2. Effects of Electrical and Optogenetic Deep Brain Stimulation on Synchronized Oscillatory Activity in Parkinsonian Basal Ganglia.

    Science.gov (United States)

    Ratnadurai-Giridharan, Shivakeshavan; Cheung, Chung C; Rubchinsky, Leonid L

    2017-11-01

    Conventional deep brain stimulation of basal ganglia uses high-frequency regular electrical pulses to treat Parkinsonian motor symptoms but has a series of limitations. Relatively new and not yet clinically tested, optogenetic stimulation is an effective experimental stimulation technique to affect pathological network dynamics. We compared the effects of electrical and optogenetic stimulation of the basal gangliaon the pathologicalParkinsonian rhythmic neural activity. We studied the network response to electrical stimulation and excitatory and inhibitory optogenetic stimulations. Different stimulations exhibit different interactions with pathological activity in the network. We studied these interactions for different network and stimulation parameter values. Optogenetic stimulation was found to be more efficient than electrical stimulation in suppressing pathological rhythmicity. Our findings indicate that optogenetic control of neural synchrony may be more efficacious than electrical control because of the different ways of how stimulations interact with network dynamics.

  3. Deep brain stimulation modulates synchrony within spatially and spectrally distinct resting state networks in Parkinson's disease.

    Science.gov (United States)

    Oswal, Ashwini; Beudel, Martijn; Zrinzo, Ludvic; Limousin, Patricia; Hariz, Marwan; Foltynie, Tom; Litvak, Vladimir; Brown, Peter

    2016-05-01

    Chronic dopamine depletion in Parkinson's disease leads to progressive motor and cognitive impairment, which is associated with the emergence of characteristic patterns of synchronous oscillatory activity within cortico-basal-ganglia circuits. Deep brain stimulation of the subthalamic nucleus is an effective treatment for Parkinson's disease, but its influence on synchronous activity in cortico-basal-ganglia loops remains to be fully characterized. Here, we demonstrate that deep brain stimulation selectively suppresses certain spatially and spectrally segregated resting state subthalamic nucleus-cortical networks. To this end we used a validated and novel approach for performing simultaneous recordings of the subthalamic nucleus and cortex using magnetoencephalography (during concurrent subthalamic nucleus deep brain stimulation). Our results highlight that clinically effective subthalamic nucleus deep brain stimulation suppresses synchrony locally within the subthalamic nucleus in the low beta oscillatory range and furthermore that the degree of this suppression correlates with clinical motor improvement. Moreover, deep brain stimulation relatively selectively suppressed synchronization of activity between the subthalamic nucleus and mesial premotor regions, including the supplementary motor areas. These mesial premotor regions were predominantly coupled to the subthalamic nucleus in the high beta frequency range, but the degree of deep brain stimulation-associated suppression in their coupling to the subthalamic nucleus was not found to correlate with motor improvement. Beta band coupling between the subthalamic nucleus and lateral motor areas was not influenced by deep brain stimulation. Motor cortical coupling with subthalamic nucleus predominantly involved driving of the subthalamic nucleus, with those drives in the higher beta frequency band having much shorter net delays to subthalamic nucleus than those in the lower beta band. These observations raise the

  4. Electrical stimulation of gut motility guided by an in silico model

    Science.gov (United States)

    Barth, Bradley B.; Henriquez, Craig S.; Grill, Warren M.; Shen, Xiling

    2017-12-01

    Objective. Neuromodulation of the central and peripheral nervous systems is becoming increasingly important for treating a diverse set of diseases—ranging from Parkinson’s Disease and epilepsy to chronic pain. However, neuromodulation of the gastrointestinal (GI) tract has achieved relatively limited success in treating functional GI disorders, which affect a significant population, because the effects of stimulation on the enteric nervous system (ENS) and gut motility are not well understood. Here we develop an integrated neuromechanical model of the ENS and assess neurostimulation strategies for enhancing gut motility, validated by in vivo experiments. Approach. The computational model included a network of enteric neurons, smooth muscle fibers, and interstitial cells of Cajal, which regulated propulsion of a virtual pellet in a model of gut motility. Main results. Simulated extracellular stimulation of ENS-mediated motility revealed that sinusoidal current at 0.5 Hz was more effective at increasing intrinsic peristalsis and reducing colon transit time than conventional higher frequency rectangular current pulses, as commonly used for neuromodulation therapy. Further analysis of the model revealed that the 0.5 Hz sinusoidal currents were more effective at modulating the pacemaker frequency of interstitial cells of Cajal. To test the predictions of the model, we conducted in vivo electrical stimulation of the distal colon while measuring bead propulsion in awake rats. Experimental results confirmed that 0.5 Hz sinusoidal currents were more effective than higher frequency pulses at enhancing gut motility. Significance. This work demonstrates an in silico GI neuromuscular model to enable GI neuromodulation parameter optimization and suggests that low frequency sinusoidal currents may improve the efficacy of GI pacing.

  5. Influência da frequência estimulatória envolvida nos efeitos analgésicos induzidos por eletroacupuntura em cervicalgia tensional Influence of the stimulating frequency involved in analgesic effects induced by electroacupuncture for neck pain due to muscular tension

    Directory of Open Access Journals (Sweden)

    P Nohama

    2009-04-01

    Full Text Available OBJETIVO: Avaliar a influência da frequência estimulatória envolvida na analgesia induzida por eletroacupuntura em cervicalgia. MÉTODOS: Comparou-se o desempenho da analgesia produzida em 2Hz, 100Hz, 1000Hz, 2500Hz e um grupo só com acupuntura, sem estímulo elétrico, avaliado por meio de algometria de pressão, Escala Visual Analógica (EVA e frequência cardíaca. Utilizou-se um estimulador elétrico microprocessado, com forma de pulso em padrão pulsado, monofásico, retangular, balanceado assimétrico, com fase secundária em exponencial decrescente, com período de estimulação de 4 segundos e repouso de 3 segundos. A amostra contou com 66 voluntários com cervicalgia tensional, idade média de 33,67±9,97 anos, 89,5% do gênero feminino e 10,5% do masculino. RESULTADOS: Não houve diferenças entre os grupos para as variáveis nota atribuída à dor pela EVA e frequência cardíaca, sendo que em todos os grupos houve melhoras analgésicas. No entanto, quando comparado o comportamento antes-depois, por meio da algometria de pressão, para um mesmo indivíduo, dentro de seu próprio grupo, houve vantagens analgésicas para o uso de 2500Hz (p=0,006 para a base da região occiptal; p=0,003 para o trapézio direito; e p=0,013 para o trapézio esquerdo, seguido de 100Hz (p=0,035, p=0,016 e p=0,038, para as mesmas regiões, respectivamente. CONCLUSÃO: Recomenda-se preferencialmente a aplicação de 2500Hz e 100Hz em eletroacupuntura para analgesia em cervicalgia tensional.OBJECTIVE: To assess the influence of the stimulating frequency involved in analgesia induced by electroacupuncture for neck pain. METHODS: The performance of the analgesia produced by 2Hz, 100Hz, 1000Hz and 2500Hz was compared with a group with acupuncture alone (without electrical stimulation, by means of pressure algometry, a visual analog scale (VAS and heart rate. We used an electrical stimulator with a microprocessor yielding standard, single-phase, rectangular and

  6. Spinal cord stimulation for neuropathic pain: current perspectives.

    Science.gov (United States)

    Wolter, Tilman

    2014-01-01

    Neuropathic pain constitutes a significant portion of chronic pain. Patients with neuropathic pain are usually more heavily burdened than patients with nociceptive pain. They suffer more often from insomnia, anxiety, and depression. Moreover, analgesic medication often has an insufficient effect on neuropathic pain. Spinal cord stimulation constitutes a therapy alternative that, to date, remains underused. In the last 10 to 15 years, it has undergone constant technical advancement. This review gives an overview of the present practice of spinal cord stimulation for chronic neuropathic pain and current developments such as high-frequency stimulation and peripheral nerve field stimulation.

  7. Stimulated brillouin backscatter of a short-pulse laser

    International Nuclear Information System (INIS)

    Hinkel, D.E.; Williams, E.A.; Berger, R.L.

    1994-01-01

    Stimulated Brillouin backscattering (SBBS) from a short-pulse laser, where the pulse length is short compared to the plasma length, is found to be qualitatively different than in the long pulse regime, where the pulse length is long compared to the plasma length. We find that after an initial transient of order the laser pulse length transit time, the instability reaches a steady state in the variables x' = x - V g t, t' = t, where V g is the pulse group velocity. In contrast, SBBS in a long pulse can be absolutely unstable and grows indefinitely, or until nonlinearities intervene. We find that the motion of the laser pulse induces Doppler related effects that substantially modify the backscattered spectrum at higher intensities, where the instability is strongly coupled (i.e. , has a growth rate large compared to the ion acoustic frequency)

  8. Workforce Development, Higher Education and Productive Systems

    Science.gov (United States)

    Hordern, Jim

    2014-01-01

    Workforce development partnerships between higher education institutions and employers involve distinctive social and technical dynamics that differ from dominant higher education practices in the UK. The New Labour government encouraged such partnerships in England, including through the use of funding that aimed to stimulate reform to…

  9. Noninvasive Deep Brain Stimulation via Temporally Interfering Electric Fields.

    Science.gov (United States)

    Grossman, Nir; Bono, David; Dedic, Nina; Kodandaramaiah, Suhasa B; Rudenko, Andrii; Suk, Ho-Jun; Cassara, Antonino M; Neufeld, Esra; Kuster, Niels; Tsai, Li-Huei; Pascual-Leone, Alvaro; Boyden, Edward S

    2017-06-01

    We report a noninvasive strategy for electrically stimulating neurons at depth. By delivering to the brain multiple electric fields at frequencies too high to recruit neural firing, but which differ by a frequency within the dynamic range of neural firing, we can electrically stimulate neurons throughout a region where interference between the multiple fields results in a prominent electric field envelope modulated at the difference frequency. We validated this temporal interference (TI) concept via modeling and physics experiments, and verified that neurons in the living mouse brain could follow the electric field envelope. We demonstrate the utility of TI stimulation by stimulating neurons in the hippocampus of living mice without recruiting neurons of the overlying cortex. Finally, we show that by altering the currents delivered to a set of immobile electrodes, we can steerably evoke different motor patterns in living mice. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Transcranial Alternating Current Stimulation Attenuates Neuronal Adaptation.

    Science.gov (United States)

    Kar, Kohitij; Duijnhouwer, Jacob; Krekelberg, Bart

    2017-03-01

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

  11. Influence of electroencephalograph bionic electrical stimulation on neuronal activities in patients with Alzheimer's disease: A functional magnetic resonance imaging study

    Directory of Open Access Journals (Sweden)

    Liling Jiang

    2018-03-01

    Full Text Available Purpose: To investigate the influence of electroencephalograph bionic electrical stimulation on neuronal activity in patients with Alzheimer's disease (AD using resting-state blood oxygen level dependent functional MRI (BOLD-fMRI and amplitude of low-frequency fluctuation (ALFF and fraction ALFF (fALFF analysis. Methods: 42 AD patients were divided into two groups in accordance with the randomized double blind principle, every group was 21. Treatment group received electroencephalograph bionic electrical stimulation. Both groups received resting-state BOLD-fMRI scanning before and after treatment and comparing differences in ALFF and fALFF in each group by statistical methods. Correlation analysis was performed between ALFF or fALFF images and neuropsychological tests scale after treatment. Results: Post-therapy brain regions with higher ALFF included left cerebellum posterior lobe, right cerebellum posterior lobe, left hippocampus/parahippocampus, left posterior cingulated cortex, left dorsolateral prefrontal cortex, right inferior parietal lobule in treatment group. Higher fALFF was observed in the right inferior parietal lobule. In the placebo group lower ALFF was observed in bilateral cerebellum posterior lobe and left posterior cingulated cortex. Alzheimer's Disease Assessment Scale-Cognitive section was closely correlated with ALFF in left cerebellum posterior lobe and right cerebellum posterior lobe. Conclusion: These results indicated improved neuronal activity in some brain areas could be achieved in AD after treatment of electroencephalograph bionic electrical stimulation. The change of BOLD-fMRI signal might provide a potential imaging strategy for studying neural mechanisms of electroencephalograph bionic electrical stimulation for AD. Keywords: Electroencephalograph bionic electrical stimulation, Alzheimer's disease, Low-frequency fluctuation, Fraction low-frequency fluctuation

  12. Closing the loop of deep brain stimulation.

    Science.gov (United States)

    Carron, Romain; Chaillet, Antoine; Filipchuk, Anton; Pasillas-Lépine, William; Hammond, Constance

    2013-12-20

    High-frequency deep brain stimulation is used to treat a wide range of brain disorders, like Parkinson's disease. The stimulated networks usually share common electrophysiological signatures, including hyperactivity and/or dysrhythmia. From a clinical perspective, HFS is expected to alleviate clinical signs without generating adverse effects. Here, we consider whether the classical open-loop HFS fulfills these criteria and outline current experimental or theoretical research on the different types of closed-loop DBS that could provide better clinical outcomes. In the first part of the review, the two routes followed by HFS-evoked axonal spikes are explored. In one direction, orthodromic spikes functionally de-afferent the stimulated nucleus from its downstream target networks. In the opposite direction, antidromic spikes prevent this nucleus from being influenced by its afferent networks. As a result, the pathological synchronized activity no longer propagates from the cortical networks to the stimulated nucleus. The overall result can be described as a reversible functional de-afferentation of the stimulated nucleus from its upstream and downstream nuclei. In the second part of the review, the latest advances in closed-loop DBS are considered. Some of the proposed approaches are based on mathematical models, which emphasize different aspects of the parkinsonian basal ganglia: excessive synchronization, abnormal firing-rate rhythms, and a deficient thalamo-cortical relay. The stimulation strategies are classified depending on the control-theory techniques on which they are based: adaptive and on-demand stimulation schemes, delayed and multi-site approaches, stimulations based on proportional and/or derivative control actions, optimal control strategies. Some of these strategies have been validated experimentally, but there is still a large reservoir of theoretical work that may point to ways of improving practical treatment.

  13. Closing the loop of deep brain stimulation

    Directory of Open Access Journals (Sweden)

    Romain eCARRON

    2013-12-01

    Full Text Available High-frequency deep brain stimulation is used to treat a wide range of brain disorders, like Parkinson's disease. The stimulated networks usually share common electrophysiological signatures, including hyperactivity and/or dysrhythmia. From a clinical perspective, HFS is expected to alleviate clinical signs without generating adverse effects. Here, we consider whether the classical open-loop HFS fulfils these criteria and outline current experimental or theoretical research on the different types of closed-loop DBS that could provide better clinical outcomes. In the first part of the review, the two routes followed by HFS-evoked axonal spikes are explored. In one direction, orthodromic spikes functionally de-afferent the stimulated nucleus from its downstream target networks. In the opposite direction, antidromic spikes prevent this nucleus from being influenced by its afferent networks. As a result, the pathological synchronized activity no longer propagates from the cortical networks to the stimulated nucleus. The overall result can be described as a reversible functional de-afferentation of the stimulated nucleus from its upstream and downstream nuclei. In the second part of the review, the latest advances in closed-loop DBS are considered. Some of the proposed approaches are based on mathematical models, which emphasize different aspects of the parkinsonian basal ganglia: excessive synchronization, abnormal firing-rate rhythms, and a deficient thalamo-cortical relay. The stimulation strategies are classified depending on the control-theory techniques on which they are based: adaptive and on-demand stimulation schemes, delayed and multi-site approaches, stimulations based on proportional and/or derivative control actions, optimal control strategies. Some of these strategies have been validated experimentally, but there is still a large reservoir of theoretical work that may point to ways of improving practical treatment.

  14. Closing the loop of deep brain stimulation

    Science.gov (United States)

    Carron, Romain; Chaillet, Antoine; Filipchuk, Anton; Pasillas-Lépine, William; Hammond, Constance

    2013-01-01

    High-frequency deep brain stimulation is used to treat a wide range of brain disorders, like Parkinson's disease. The stimulated networks usually share common electrophysiological signatures, including hyperactivity and/or dysrhythmia. From a clinical perspective, HFS is expected to alleviate clinical signs without generating adverse effects. Here, we consider whether the classical open-loop HFS fulfills these criteria and outline current experimental or theoretical research on the different types of closed-loop DBS that could provide better clinical outcomes. In the first part of the review, the two routes followed by HFS-evoked axonal spikes are explored. In one direction, orthodromic spikes functionally de-afferent the stimulated nucleus from its downstream target networks. In the opposite direction, antidromic spikes prevent this nucleus from being influenced by its afferent networks. As a result, the pathological synchronized activity no longer propagates from the cortical networks to the stimulated nucleus. The overall result can be described as a reversible functional de-afferentation of the stimulated nucleus from its upstream and downstream nuclei. In the second part of the review, the latest advances in closed-loop DBS are considered. Some of the proposed approaches are based on mathematical models, which emphasize different aspects of the parkinsonian basal ganglia: excessive synchronization, abnormal firing-rate rhythms, and a deficient thalamo-cortical relay. The stimulation strategies are classified depending on the control-theory techniques on which they are based: adaptive and on-demand stimulation schemes, delayed and multi-site approaches, stimulations based on proportional and/or derivative control actions, optimal control strategies. Some of these strategies have been validated experimentally, but there is still a large reservoir of theoretical work that may point to ways of improving practical treatment. PMID:24391555

  15. Electroacupuncture stimulation using different frequencies (10 and 100 Hz changes the energy metabolism in induced hyperglycemic rats Eletroacupuntura usando diferentes freqüências (10 e 100 Hz altera o metabolismo energético em ratos hiperglicêmicos induzidos

    Directory of Open Access Journals (Sweden)

    Lanese Medeiros Figueiredo

    2011-01-01

    Full Text Available PURPOSE: To investigate the effect of 10 and 100 Hz peripheral electro-estimulation (electroacupuncture, EAc at Zusanli (ST-36 and Zhongwan (CV-12 acupoints on blood glucose and lactate levels and tissue (liver and kidney concentrations of lactate in hyperglycemic induced anesthetized rats. METHODS: Thirty-six rats were randomly assigned to 3 groups (n=12: G1: basal (anesthesia: ketamine (90mg kg-1 body weight+ xylazine (10mg/kg-1 body weight, i.p.; G2: anesthesia+EA10Hz EAc and G3: anesthesia+EA100Hz EAc. EAc stimulation was delivered for 30 min at 10 mA at selected acupoints. Blood and tissue (kidney, liver samples were collected at the end of the EAc application (n=6, T30 and 30 minutes later (n=6, T60 for biochemical analysis. G1 samples were collected at the same timepoints. ANOVA followed by Tukey's Multiple Comparison Test was used for statistical analyses. RESULTS: Glycemia decreased significantly (p0.001 in G2/G3 rats at T-60 and at T30 timepoints in G2 compared with G1 rats. Lactacedemia decreased significantly at T30 timepoint in G2 compared with G1 rats. G1/G3 tissue lactate levels were not different. CONCLUSIONS: Electroacupuncture (10 Hz applied to St-36 and CV-12 acupoints decreases glycemia and lactacedemia and liver and kidney lactate concentrations. We hypothesize that the decrease in lactate levels may be related to greater energy production due to enhanced lactate to pyruvate conversion. Higher frequency (100 Hz failed to promote the same effect.OBJETIVO: Investigar o efeito da eletroacupuntura (10-100 Hz aplicada nos acupontos Zusanli (ST-36 e Zhongwan (CV-12 sobre a glicemia, lactacedemia e concentrações de lactato no fígado/rim em ratos anestesiados. MÉTODOS: Trinta e seis ratos foram distribuídos aleatoriamente em três grupos (n= 12: G1: basal (anestesia: cetamina (90mg kg-1+xilazina (10mg/kg-1, ip, G2: anestesia+10Hz EAc e G3: anestesia+100Hz EAc. EAc foi aplicada por 30 min (10 mA em acupontos selecionados

  16. Frequency Rates and Correlates of Contrapower Harassment in Higher Education

    Science.gov (United States)

    DeSouza, Eros R.

    2011-01-01

    The current study investigated incivility, sexual harassment, and racial-ethnic harassment simultaneously when the targets were faculty members and the perpetrators were students (i.e., academic contrapower harassment; ACH). The sample constituted 257 faculty members (90% were White and 53% were women) from a medium-sized state university in the…

  17. Anal sphincter responses after perianal electrical stimulation

    DEFF Research Database (Denmark)

    Pedersen, Ejnar; Klemar, B; Schrøder, H D

    1982-01-01

    By perianal electrical stimulation and EMG recording from the external anal sphincter three responses were found with latencies of 2-8, 13-18 and 30-60 ms, respectively. The two first responses were recorded in most cases. They were characterised by constant latency and uniform pattern, were...... not fatigued by repeated stimulation, were most dependent on placement of stimulating and recording electrodes, and always had a higher threshold than the third response. The third response was constantly present in normal subjects. It had the longest EMG response and the latency decreased with increasing...... stimulation to a minimum of 30-60 ms. This response represented the clinical observable spinal reflex, "the classical anal reflex". The latencies of the two first responses were so short that they probably do not represent spinal reflexes. This was further supported by the effect of epidural anaesthesia which...

  18. Thermally stimulated exoelectron emission from solid Xe

    International Nuclear Information System (INIS)

    Khyzhniy, I.V.; Grigorashchenko, O.N.; Savchenko, E.V.; Ponomarev, A.N.; Bondybey, V.E.

    2007-01-01

    Thermally-stimulated emission of exoelectrons and photons from solid Xe pre-irradiated by low-energy electrons were studied. A high sensitivity of thermally-stimulated luminescence (TSL) and thermally-stimulated exoelectron emission (TSEE) to sample prehistory was demonstrated. It was shown that electron traps in unannealed samples are characterized by much broader distribution of trap levels in comparison with annealed samples and their concentration exceeds in number that in annealed samples. Both phenomena, TSL and TSEE, were found to be triggered by release of electrons from the same kind of traps. The data obtained suggest a competition between two relaxation channels: charge recombination and electron transport terminated by TSL and TSEE. It was found that TSEE predominates at low temperatures while at higher temperatures TSL prevails. An additional relaxation channel, a photon-stimulated exoelectron emission pre-irradiated solid Xe, was revealed

  19. Pathways of translation: deep brain stimulation.

    Science.gov (United States)

    Gionfriddo, Michael R; Greenberg, Alexandra J; Wahegaonkar, Abhijeet L; Lee, Kendall H

    2013-12-01

    Electrical stimulation of the brain has a 2000 year history. Deep brain stimulation (DBS), one form of neurostimulation, is a functional neurosurgical approach in which a high-frequency electrical current stimulates targeted brain structures for therapeutic benefit. It is an effective treatment for certain neuropathologic movement disorders and an emerging therapy for psychiatric conditions and epilepsy. Its translational journey did not follow the typical bench-to-bedside path, but rather reversed the process. The shift from ancient and medieval folkloric remedy to accepted medical practice began with independent discoveries about electricity during the 19th century and was fostered by technological advances of the 20th. In this paper, we review that journey and discuss how the quest to expand its applications and improve outcomes is taking DBS from the bedside back to the bench. © 2013 Wiley Periodicals, Inc.

  20. Effects of stimulation parameters and electrode location on thresholds for epidural stimulation of cat motor cortex

    Science.gov (United States)

    Wongsarnpigoon, Amorn; Grill, Warren M.

    2011-12-01

    Epidural electrical stimulation (ECS) of the motor cortex is a developing therapy for neurological disorders. Both placement and programming of ECS systems may affect the therapeutic outcome, but the treatment parameters that will maximize therapeutic outcomes and minimize side effects are not known. We delivered ECS to the motor cortex of anesthetized cats and investigated the effects of electrode placement and stimulation parameters on thresholds for evoking motor responses in the contralateral forelimb. Thresholds were inversely related to stimulation frequency and the number of pulses per stimulus train. Thresholds were lower over the forelimb representation in motor cortex (primary site) than surrounding sites (secondary sites), and thresholds at sites 4 mm away. Electrode location and montage influenced the effects of polarity on thresholds: monopolar anodic and cathodic thresholds were not significantly different over the primary site, cathodic thresholds were significantly lower than anodic thresholds over secondary sites and bipolar thresholds were significantly lower with the anode over the primary site than with the cathode over the primary site. A majority of bipolar thresholds were either between or equal to the respective monopolar thresholds, but several bipolar thresholds were greater than or less than the monopolar thresholds of both the anode and cathode. During bipolar stimulation, thresholds were influenced by both electric field superposition and indirect, synaptically mediated interactions. These results demonstrate the influence of stimulation parameters and electrode location during cortical stimulation, and these effects should be considered during the programming of systems for therapeutic cortical stimulation.

  1. Direct Acoustic Stimulation at the Lateral Canal: An Alternative Route to the Inner Ear?

    Directory of Open Access Journals (Sweden)

    Nicolas Verhaert

    Full Text Available Severe to profound mixed hearing loss is associated with hearing rehabilitation difficulties. Recently, promising results for speech understanding were obtained with a direct acoustic cochlear implant (DACI. The surgical implantation of a DACI with standard coupling through a stapedotomy can however be regarded as challenging. Therefore, in this experimental study, the feasibility of direct acoustic stimulation was investigated at an anatomically and surgically more accessible inner ear site. DACI stimulation of the intact, blue-lined and opened lateral semicircular canal (LC was investigated and compared with standard oval window (OW coupling. Additionally, stapes footplate fixation was induced. Round window (RW velocity, as a measure of the performance of the device and its coupling efficiency, was determined in fresh-frozen human cadaver heads. Using single point laser Doppler vibrometry, RW velocity could reliably be measured in low and middle frequency range, and equivalent sound pressure level (LE output was calculated. Results for the different conditions obtained in five heads were analyzed in subsequent frequency ranges. Comparing the difference in RW membrane velocity showed higher LE in the LC opened condition [mean: 103 equivalent dB SPL], than in LC intact or blue-lined conditions [63 and 74 equivalent dB SPL, respectively]. No difference was observed between the LC opened and the standard OW condition. Inducing stapes fixation, however, led to a difference in the low frequency range of LE compared to LC opened. In conclusion, this feasibility study showed promising results for direct acoustic stimulation at this specific anatomically and surgically more accessible inner ear site. Future studies are needed to address the impact of LC stimulation on cochlear micromechanics and on the vestibular system like dizziness and risks of hearing loss.

  2. Ipsilateral masking between acoustic and electric stimulations.

    Science.gov (United States)

    Lin, Payton; Turner, Christopher W; Gantz, Bruce J; Djalilian, Hamid R; Zeng, Fan-Gang

    2011-08-01

    Residual acoustic hearing can be preserved in the same ear following cochlear implantation with minimally traumatic surgical techniques and short-electrode arrays. The combined electric-acoustic stimulation significantly improves cochlear implant performance, particularly speech recognition in noise. The present study measures simultaneous masking by electric pulses on acoustic pure tones, or vice versa, to investigate electric-acoustic interactions and their underlying psychophysical mechanisms. Six subjects, with acoustic hearing preserved at low frequencies in their implanted ear, participated in the study. One subject had a fully inserted 24 mm Nucleus Freedom array and five subjects had Iowa/Nucleus hybrid implants that were only 10 mm in length. Electric masking data of the long-electrode subject showed that stimulation from the most apical electrodes produced threshold elevations over 10 dB for 500, 625, and 750 Hz probe tones, but no elevation for 125 and 250 Hz tones. On the contrary, electric stimulation did not produce any electric masking in the short-electrode subjects. In the acoustic masking experiment, 125-750 Hz pure tones were used to acoustically mask electric stimulation. The acoustic masking results showed that, independent of pure tone frequency, both long- and short-electrode subjects showed threshold elevations at apical and basal electrodes. The present results can be interpreted in terms of underlying physiological mechanisms related to either place-dependent peripheral masking or place-independent central masking.

  3. Estimulação elétrica neuromuscular de média freqüência (russa em cães com atrofia muscular induzida Medium frequency neuromuscular electrical stimulation (russian in dogs with induced muscle atrophy

    Directory of Open Access Journals (Sweden)

    Charles Pelizzari

    2008-06-01

    Full Text Available A estimulação elétrica neuromuscular (EENM de média freqüência (Russa ou de Kotz pode ser empregada para a recuperação de massa muscular em animais apresentando atrofia muscular por desuso. Assim, o objetivo deste trabalho foi empregar a EENM de média freqüência no quadríceps femoral de cães com atrofia muscular induzida, avaliando-se a ocorrência de ganho de massa. Foram utilizados oito cães em dois grupos denominados de GI ou controle e de GII ou tratado. Para a indução da atrofia muscular, a articulação fêmoro-tíbio-patelar esquerda foi imobilizada por 30 dias. Após 48 horas da remoção, foi realizada a EENM nos cães do grupo II, três vezes por semana, com intervalo de 48 horas cada sessão, pelo período de 60 dias. Foram avaliadas a mensuração da perimetria da coxa, da goniometria do joelho, as enzimas creatina-quinase (CK e morfometria das fibras musculares em cortes transversais do músculo vasto lateral, colhido mediante a biópsia muscular. A EENM foi empregada no músculo quadríceps femoral numa freqüência de 2.500Hz, largura de pulso de 50% e relação de tempo on/off de 1:2. Não houve diferença significativa quanto aos valores de perimetria da coxa e a atividade da enzima CK entre os grupos I e II. Na goniometria, houve diminuição significativa (PThe medium frequency neuromuscular electrical stimulation (NMES (Russa or Kotz is designed for recuperation of muscle mass in dogs with muscular atrophy in disuse. This study aims to utilize medium frequency NMES on the femoral quadriceps of dogs with induced muscular atrophy and evaluate the occurrence of gain in mass. Eight dogs in two groups denominated GI, or control, and GII, or treated were used. For the induction of muscular atrophy, the left femoral-tibial-patellar joint was immobilized for 30 days. NMES treatment began 48 hours after the removal of the immobilization device on dogs from group II and was carried out three times per week, with an

  4. Effect of high-frequency excitation on natural frequencies of spinning discs

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2000-01-01

    The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural frequenc......The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural...

  5. Comparing Properties (Concentration, PH and mutans streptococcus Saliva in Both Status Resting Saliva and Stimulated Saliva in Preschoolers of Kerman city

    Directory of Open Access Journals (Sweden)

    Elham Farokh-Gisour,

    2016-08-01

    Full Text Available This paper aimed to compare the characteristics (concentration, PH and mutans streptococcus saliva in both status resting saliva and stimulated saliva in preschoolers of Kerman city. In this study, 100 children aged 5 years among patients admitted to the pediatric ward of Kerman dental school and dental offices, some experts in Kerman dental school participated. Resting and stimulated saliva (after chewing oral paraffin children collected and in concentrations, PH and the amount of mutans streptococcus was measured. Mc Nemar test to compare the frequency of positive and negative cultures before and after stimulation as well as paired t-test to compare the saliva pH and concentration of not stimulated saliva and stimulated saliva in two modes was used. The significance level was set less than 0.05.The mean resting salivary osmolality of the population: 30.42 ± 87.41 and the average salivary osmolality of the total population were 79.81. Osmolality differences in saliva before and after stimulation with each other was significant (p = 0.009, paired t-test. The mean of resting saliva in the total population PH 0.45 ± 7.78 and the average PH stimulated saliva in the total population was 8.22 and the difference before and after each significant (p = 0.02, paired t-test. In mutans streptococcus in test samples in all 71 patients (71% positive test and 29 patients (29% had a negative test that number of positive cultures are equal before and after stimulation of saliva and thus the difference between the two groups (p> 0.05 was observed. In terms of comparing the properties of resting and stimulated saliva can conclude that salivary stimulated PH was significantly higher than resting saliva. While stimulated saliva osmolality was significantly less than resting saliva and the frequency of positive test mutans streptococcus in saliva before and after stimulation had no significant difference (p> 0.05. This means that test results on samples of mutans

  6. Subjective sleep quality, unstimulated sexual arousal, and sexual frequency

    Directory of Open Access Journals (Sweden)

    Rui Costa

    Full Text Available Introduction: REM sleep deprivation increases unstimulated erections in rats, and total sleep deprivation increases erections during audiovisual sexual stimulation in men, but the effects of sleep problems on human unstimulated sexual arousal are unknown. Objective: We examined the associations of subjective sleep quality with unstimulated sexual arousal, satisfaction with sex life, and sexual frequency and desire over the past month. Methods: 275 Portuguese (169 women reported their anxiety, sexual arousal and sexual desire during a resting state, and completed the Pittsburgh Sleep Quality Index, the sexual satisfaction subscale of the LiSat scale, the Desire dimensions of the Female Sexual Function Index (women only and International Index of Erectile Function (men only. They additionally reported how many days in the past month they engaged in penile-vaginal intercourse, noncoital sex, and masturbation. Salivary testosterone (T was assayed by luminescence immunoassays. Results: Poorer sleep quality correlated with greater unstimulated sexual arousal in men with higher T levels and in women with higher T levels not taking oral contraceptives. In women with lower T, poorer subjective sleep quality correlated with greater sexual dissatisfaction. In both sexes, sleep quality was uncorrelated with sexual desire and sexual frequency over the past month. Discussion: Consistently with other studies in humans and animals, the findings are congruent with the notion that lack of sleep can increase sexual arousal, but not sexual frequency. T might play a role in the sexual arousal caused by lack of appropriate sleep.

  7. Microwave Frequency Multiplier

    Science.gov (United States)

    Velazco, J. E.

    2017-02-01

    High-power microwave radiation is used in the Deep Space Network (DSN) and Goldstone Solar System Radar (GSSR) for uplink communications with spacecraft and for monitoring asteroids and space debris, respectively. Intense X-band (7.1 to 8.6 GHz) microwave signals are produced for these applications via klystron and traveling-wave microwave vacuum tubes. In order to achieve higher data rate communications with spacecraft, the DSN is planning to gradually furnish several of its deep space stations with uplink systems that employ Ka-band (34-GHz) radiation. Also, the next generation of planetary radar, such as Ka-Band Objects Observation and Monitoring (KaBOOM), is considering frequencies in the Ka-band range (34 to 36 GHz) in order to achieve higher target resolution. Current commercial Ka-band sources are limited to power levels that range from hundreds of watts up to a kilowatt and, at the high-power end, tend to suffer from poor reliability. In either case, there is a clear need for stable Ka-band sources that can produce kilowatts of power with high reliability. In this article, we present a new concept for high-power, high-frequency generation (including Ka-band) that we refer to as the microwave frequency multiplier (MFM). The MFM is a two-cavity vacuum tube concept where low-frequency (2 to 8 GHz) power is fed into the input cavity to modulate and accelerate an electron beam. In the second cavity, the modulated electron beam excites and amplifies high-power microwaves at a frequency that is a multiple integer of the input cavity's frequency. Frequency multiplication factors in the 4 to 10 range are being considered for the current application, although higher multiplication factors are feasible. This novel beam-wave interaction allows the MFM to produce high-power, high-frequency radiation with high efficiency. A key feature of the MFM is that it uses significantly larger cavities than its klystron counterparts, thus greatly reducing power density and arcing

  8. Effect of low-level laser stimulation on EEG.

    Science.gov (United States)

    Wu, Jih-Huah; Chang, Wen-Dien; Hsieh, Chang-Wei; Jiang, Joe-Air; Fang, Wei; Shan, Yi-Chia; Chang, Yang-Chyuan

    2012-01-01

    Conventional laser stimulation at the acupoint can induce significant brain activation, and the activation is theoretically conveyed by the sensory afferents. Whether the insensible low-level Laser stimulation outside the acupoint could also evoke electroencephalographic (EEG) changes is not known. We designed a low-level laser array stimulator (6 pcs laser diode, wavelength 830 nm, output power 7 mW, and operation frequency 10 Hz) to deliver insensible laser stimulations to the palm. EEG activities before, during, and after the laser stimulation were collected. The amplitude powers of each EEG frequency band were analyzed. We found that the low-level laser stimulation was able to increase the power of alpha rhythms and theta waves, mainly in the posterior head regions. These effects lasted at least 15 minutes after cessation of the laser stimulation. The amplitude power of beta activities in the anterior head regions decreased after laser stimulation. We thought these EEG changes comparable to those in meditation.

  9. Effect of Low-Level Laser Stimulation on EEG

    Directory of Open Access Journals (Sweden)

    Jih-Huah Wu

    2012-01-01

    Full Text Available Conventional laser stimulation at the acupoint can induce significant brain activation, and the activation is theoretically conveyed by the sensory afferents. Whether the insensible low-level Laser stimulation outside the acupoint could also evoke electroencephalographic (EEG changes is not known. We designed a low-level laser array stimulator (6 pcs laser diode, wavelength 830 nm, output power 7 mW, and operation frequency 10 Hz to deliver insensible laser stimulations to the palm. EEG activities before, during, and after the laser stimulation were collected. The amplitude powers of each EEG frequency band were analyzed. We found that the low-level laser stimulation was able to increase the power of alpha rhythms and theta waves, mainly in the posterior head regions. These effects lasted at least 15 minutes after cessation of the laser stimulation. The amplitude power of beta activities in the anterior head regions decreased after laser stimulation. We thought these EEG changes comparable to those in meditation.

  10. Sensitivity evaluation in air and water caloric stimulation of the vestibular organs using videonystagmography.

    Science.gov (United States)

    Jałocha-Kaczka, Anna; Pietkiewicz, Piotr; Zielińska-Bliźniewska, Hanna; Miłoński, Jarosław; Olszewski, Jurek

    2014-01-01

    The aim of the study was to compare air and water caloric stimulation of the vestibular organs using videonystagmography (VNG). The study covered 18 women aged 21-63 and 11 men aged 21-74 years hospitalized at the ENT, without complaints for vertigo and/or balance disorders. The alternate binaural bithermal caloric test with cool 30°C and warm 44°C air or water irrigations (after 2h interval for the recordings) with the use of VNG was done. All parameters of air and water vestibular caloric stimulations, assessed in the VNG, differed significantly but were within the normal range. The research showed a statistically significant difference between canal paresis but only for the left ear at 30°C and 44°C. Absolute directional preponderance, relative directional preponderance, vestibular excitability, slow component velocity, frequency were different statistically for both ears at both temperatures. Our study showed that both air and water caloric stimulations were able to distinguish physiological and impaired vestibular function. The obtained results showed statistically higher response for water than air stimulation. Copyright © 2014 Polish Otorhinolaryngology - Head and Neck Surgery Society. Published by Elsevier Urban & Partner Sp. z.o.o. All rights reserved.

  11. Sphenopalatine ganglion stimulation induces changes in cardiac autonomic regulation in cluster headache

    DEFF Research Database (Denmark)

    Barloese, Mads; Petersen, Anja S; Guo, Song

    2018-01-01

    regulation. MATERIALS AND METHODS: In a double-blind, randomized, sham-controlled crossover design, patients received low-frequency and sham stimulation. RR intervals were recorded, and heart rate variability was analysed (time-domain, frequency-domain, nonlinear parameters). Headache characteristics......-frequency stimulation, there was a greater increase in heart rate compared to sham (Ptime domain (P...INTRODUCTION: Cluster headache is characterized by attacks of severe unilateral pain accompanied by cranial and systemic autonomic changes. Our knowledge of the latter is imperfect. This study aimed to investigate the effect of low-frequency sphenopalatine ganglion stimulation on cardiac autonomic...

  12. Transverse tripolar spinal cord stimulation: results of an international multicenter study.

    Science.gov (United States)

    Oakley, John C; Espinosa, Francisco; Bothe, Hans; McKean, John; Allen, Peter; Burchiel, Kim; Quartey, Gilbert; Spincemaille, Geert; Nuttin, Bart; Gielen, Frans; King, Gary; Holsheimer, Jan

    2006-07-01

    Experienced neurosurgeons at eight spinal cord stimulation centers in the United States, Canada, and Europe participated in a study from 1997 to 2000 investigating the safety, performance, and efficacy of a Transverse Tripolar Stimulation (TTS) system invented at the University of Twente, the Netherlands. This device was proposed to improve the ability of spinal cord stimulation to adequately overlap paresthesia to perceived areas of pain. Fifty-six patients with chronic, intractable neuropathic pain of the trunk and/or limbs more than three months' duration (average 105 months) were enrolled with follow-up periods at 4, 12, 26, and 52 weeks. All patients had a new paddle-type lead implanted with four electrodes, three of them aligned in a row perpendicular to the cord. Fifteen of these patients did not undergo permanent implantation. Of the 41 patients internalized, 20 patients chose conventional programming using an implanted pulse generator to drive four electrodes, while 21 patients chose a tripole stimulation system, which used radiofrequency power and signal transmission and an implanted dual-channel receiver to drive three electrodes using simultaneous pulses of independently variable amplitude. On average, the visual analog scale scores dropped more for patients with TTS systems (32%) than for conventional polarity systems (16%). Conventional polarity systems were using higher frequencies on average, while usage range was similar. Most impressive was the well-controlled "steering" of the paresthesias according to the dermatomal topography of the dorsal columns when using the TTS-balanced pulse driver. The most common complication was lead migration. While the transverse stimulation system produced acceptable outcomes for overall pain relief, an analysis of individual pain patterns suggests that it behaves like spinal cord stimulation in general with the best control of extremity neuropathic pain. This transverse tripole lead and driving system introduced

  13. How to target inter-regional phase synchronization with dual-site Transcranial Alternating Current Stimulation

    DEFF Research Database (Denmark)

    Saturnino, Guilherme Bicalho; Madsen, Kristoffer Hougaard; Siebner, Hartwig Roman

    2017-01-01

    oscillations in two connected cortical areas. While the frequency of ds-TACS is matched, the phase of stimulation is either identical (in-phase stimulation) or opposite (anti-phase stimulation) in the two cortical target areas. In-phase stimulation is thought to synchronize the endogenous oscillations...... and hereby to improve behavioral performance. Conversely, anti-phase stimulation is thought to desynchronize neural oscillations in the two areas, which is expected to decrease performance. Critically, in- and anti-phase ds-TACS should only differ with respect to temporal phase, while all other stimulation...... unambiguously the causal contribution of phase coupling to specific cognitive processes in the human brain....

  14. New York Canyon Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Raemy, Bernard

    2012-06-21

    The New York Canyon Stimulation Project was to demonstrate the commercial application of Enhanced Geothermal System techniques in Buena Vista Valley area of Pershing County, Nevada. From October 2009 to early 2012, TGP Development Company aggressively implemented Phase I of Pre-Stimulation and Site/Wellbore readiness. This included: geological studies; water studies and analyses and procurement of initial permits for drilling. Oversubscription of water rights and lack of water needed for implementation of EGS were identified and remained primary obstacles. Despite extended efforts to find alternative solutions, the water supply circumstances could not be overcome and led TGP to determine a "No Go" decision and initiate project termination in April 2012.

  15. Frequency-specific insight into short-term memory capacity

    OpenAIRE

    Feurra, Matteo; Galli, Giulia; Pavone, Enea Francesco; Rossi, Alessandro; Rossi, Simone

    2016-01-01

    We provided novel evidence of a frequency-specific effect by transcranial alternating current stimulation (tACS) of the left posterior parietal cortex on short-term memory, during a digit span task. the effect was prominent with stimulation at beta frequency for young and not for middle-aged adults and correlated with age. Our findings highlighted a short-term memory capacity improvement by tACS application.

  16. Mutual Information in Frequency and Its Application to Measure Cross-Frequency Coupling in Epilepsy

    Science.gov (United States)

    Malladi, Rakesh; Johnson, Don H.; Kalamangalam, Giridhar P.; Tandon, Nitin; Aazhang, Behnaam

    2018-06-01

    We define a metric, mutual information in frequency (MI-in-frequency), to detect and quantify the statistical dependence between different frequency components in the data, referred to as cross-frequency coupling and apply it to electrophysiological recordings from the brain to infer cross-frequency coupling. The current metrics used to quantify the cross-frequency coupling in neuroscience cannot detect if two frequency components in non-Gaussian brain recordings are statistically independent or not. Our MI-in-frequency metric, based on Shannon's mutual information between the Cramer's representation of stochastic processes, overcomes this shortcoming and can detect statistical dependence in frequency between non-Gaussian signals. We then describe two data-driven estimators of MI-in-frequency: one based on kernel density estimation and the other based on the nearest neighbor algorithm and validate their performance on simulated data. We then use MI-in-frequency to estimate mutual information between two data streams that are dependent across time, without making any parametric model assumptions. Finally, we use the MI-in- frequency metric to investigate the cross-frequency coupling in seizure onset zone from electrocorticographic recordings during seizures. The inferred cross-frequency coupling characteristics are essential to optimize the spatial and spectral parameters of electrical stimulation based treatments of epilepsy.

  17. Transcranial magnetic stimulation changes response selectivity of neurons in the visual cortex

    Science.gov (United States)

    Kim, Taekjun; Allen, Elena A.; Pasley, Brian N.; Freeman, Ralph D.

    2015-01-01

    Background Transcranial magnetic stimulation (TMS) is used to selectively alter neuronal activity of specific regions in the cerebral cortex. TMS is reported to induce either transient disruption or enhancement of different neural functions. However, its effects on tuning properties of sensory neurons have not been studied quantitatively. Objective/Hypothesis Here, we use specific TMS application parameters to determine how they may alter tuning characteristics (orientation, spatial frequency, and contrast sensitivity) of single neurons in the cat’s visual cortex. Methods Single unit spikes were recorded with tungsten microelectrodes from the visual cortex of anesthetized and paralyzed cats (12 males). Repetitive TMS (4Hz, 4sec) was delivered with a 70mm figure-8 coil. We quantified basic tuning parameters of individual neurons for each pre- and post-TMS condition. The statistical significance of changes for each tuning parameter between the two conditions was evaluated with a Wilcoxon signed-rank test. Results We generally find long-lasting suppression which persists well beyond the stimulation period. Pre- and post-TMS orientation tuning curves show constant peak values. However, strong suppression at non-preferred orientations tends to narrow the widths of tuning curves. Spatial frequency tuning exhibits an asymmetric change in overall shape, which results in an emphasis on higher frequencies. Contrast tuning curves show nonlinear changes consistent with a gain control mechanism. Conclusions These findings suggest that TMS causes extended interruption of the balance between sub-cortical and intra-cortical inputs. PMID:25862599

  18. Academically Ambitious and Relevant Higher Education Research: The Legacy of the Consortium of Higher Education Researchers

    Science.gov (United States)

    Teichler, Ulrich

    2013-01-01

    The Consortium of Higher Education Researchers (CHER) was founded in 1988 to stimulate international communication and collaboration of higher education researchers. A need was felt to offset the isolation of the small numbers of scholars in this area of expertise in many countries, as well as the isolation of individual disciplines addressing…

  19. Utilization of multiple frequencies in 3D nonlinear microwave imaging

    DEFF Research Database (Denmark)

    Jensen, Peter Damsgaard; Rubæk, Tonny; Mohr, Johan Jacob

    2012-01-01

    The use of multiple frequencies in a nonlinear microwave algorithm is considered. Using multiple frequencies allows for obtaining the improved resolution available at the higher frequencies while retaining the regularizing effects of the lower frequencies. However, a number of different challenges...... at lower frequencies are used as starting guesses for reconstructions at higher frequencies. The performance is illustrated using simulated 2-D data and data obtained with the 3-D DTU microwave imaging system....

  20. IDEA: Stimulating Oral Production.

    Science.gov (United States)

    Easley, Jacob J.

    1995-01-01

    Presents daily activities that facilitate complete sentence response, promote oral production, and aid the learning of vocabulary in foreign-language classes. Because speech is the primary form of communication in the foreign-language classroom, it is important to stimulate students to converse as soon as possible. (Author/CK)

  1. stimulated BV2 Microglial

    African Journals Online (AJOL)

    2012-03-26

    Mar 26, 2012 ... 2), in LPS-stimulated BV2 microglial cells. The level of NO production was analyzed using Griess reaction. The release of PGE2 was determined using sandwich enzyme-linked immunosorbent assay. The DNA-binding activity of nuclear factor-κB (NF-κB) was measured by electrophoretic mobility shift assay ...

  2. Brain stimulation in migraine.

    Science.gov (United States)

    Brighina, Filippo; Cosentino, Giuseppe; Fierro, Brigida

    2013-01-01

    Migraine is a very prevalent disease with great individual disability and socioeconomic burden. Despite intensive research effort in recent years, the etiopathogenesis of the disease remains to be elucidated. Recently, much importance has been given to mechanisms underlying the cortical excitability that has been suggested to be dysfunctional in migraine. In recent years, noninvasive brain stimulation techniques based on magnetic fields (transcranial magnetic stimulation, TMS) and on direct electrical currents (transcranial direct current stimulation, tDCS) have been shown to be safe and effective tools to explore the issue of cortical excitability, activation, and plasticity in migraine. Moreover, TMS, repetitive TMS (rTMS), and tDCS, thanks to their ability to interfere with and/or modulate cortical activity inducing plastic, persistent effects, have been also explored as potential therapeutic approaches, opening an interesting perspective for noninvasive neurostimulation for both symptomatic and preventive treatment of migraine and other types of headache. In this chapter we critically review evidence regarding the role of noninvasive brain stimulation in the pathophysiology and treatment of migraine, delineating the advantages and limits of these techniques together with potential development and future application. © 2013 Elsevier B.V. All rights reserved.

  3. Transcutaneous electrical nerve stimulation (TENS) improves the diabetic cytopathy (DCP) via up-regulation of CGRP and cAMP.

    Science.gov (United States)

    Ding, Liucheng; Song, Tao; Yi, Chaoran; Huang, Yi; Yu, Wen; Ling, Lin; Dai, Yutian; Wei, Zhongqing

    2013-01-01

    The objective of this study was to investigate the effects and mechanism of Transcutaneous Electrical Nerve Stimulation (TENS) on the diabetic cytopathy (DCP) in the diabetic bladder. A total of 45 rats were randomly divided into diabetes mellitus (DM)/TENS group (n=15), DM group (n=15) and control group (n=15). The rats in the DM/TENS and TENS groups were electronically stimulated (stimulating parameters: intensity-31 V, frequency-31 Hz, and duration of stimulation of 15 min) for three weeks. Bladder histology, urodynamics and contractile responses to field stimulation and carbachol were determined. The expression of calcitonin gene-related peptide (CGRP) was analyzed by RT-PCR and Western blotting. The results showed that contractile responses of the DM rats were ameliorated after 3 weeks of TENS. Furthermore, TENS significantly increased bladder wet weight, volume threshold for micturition and reduced PVR, V% and cAMP content of the bladder. The mRNA and protein levels of CGRP in dorsal root ganglion (DRG) in the DM/TENS group were higher than those in the DM group. TENS also significantly up-regulated the cAMP content in the bladder body and base compared with diabetic rats. We conclude that TENS can significantly improve the urine contractility and ameliorate the feeling of bladder fullness in DM rats possibly via up-regulation of cAMP and CGRP in DRG.

  4. The Underlying Mechanism of Preventing Facial Nerve Stimulation by Triphasic Pulse Stimulation in Cochlear Implant Users Assessed With Objective Measure.

    Science.gov (United States)

    Bahmer, Andreas; Baumann, Uwe

    2016-10-01

    Triphasic pulse stimulation prevents from facial nerve stimulation (FNS) because of a different electromyographic input-output function compared with biphasic pulse stimulation. FNS is sometimes observed in cochlear implant users as an unwanted side effect of electrical stimulation of the auditory nerve. The common stimulation applied in current cochlear implant consists of biphasic pulse patterns. Two common clinical remedies to prevent unpleasant FNS caused by activation of certain electrodes are to expand their pulse phase duration or simply deactivate them. Unfortunately, in some patients these methods do not provide sufficient FNS prevention. In these patients triphasic pulse can prevent from FNS. The underlying mechanism is yet unclear. Electromyographic (EMG) recordings of muscles innervated by the facial nerve (musculi orbicularis ori and oculi) were applied to quantitatively assess the effects on FNS. Triphasic and biphasic fitting maps were compared in four subjects with severe FNS. Based on the recordings, a model is presented which intends to explain the beneficial effects of triphasic pulse application. Triphasic stimulation provided by fitting of an OPUS 2 speech processor device. For three patients, EMG was successfully recorded depending on stimulation level up to uncomfortable and intolerable FNS stimulation as upper boarder. The obtained EMG recordings demonstrated high individual variability. However, a difference between the input-output function for biphasic and triphasic pulse stimulation was visually observable. Compared with standard biphasic stimulation, triphasic pulses require higher stimulation levels to elicit an equal amount of FNS, as reflected by EMG amplitudes. In addition, we assum