The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Pierre Besson - One of the best experts on this subject based on the ideXlab platform.
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Concurrent anodal transcranial direct-current stimulation and Motor Task to influence sensoriMotor cortex activation.
Brain research, 2019Co-Authors: Pierre Besson, Makii Muthalib, Gérard Dray, John C. Rothwell, Stéphane PerreyAbstract:Abstract Functional targeting with anodal high-definition transcranial direct current stimulation (HD-atDCS) of involved brain areas during performance of a Motor Task (online) may facilitate sensoriMotor cortex neuroplasticity compared to performing the Motor Task after HD-atDCS (offline). The aim of this study was to employ functional near-infrared spectroscopy to compare the time course of Motor Task-related changes in sensoriMotor cortex activation between online and offline HD-atDCS. We hypothesized that online HD-atDCS would have a greater effect on Task-related sensoriMotor cortex activation than offline HD-atDCS. In a within-subject sham controlled and randomized study design, 9 healthy participants underwent 3 HD-atDCS sessions (online, offline and sham) targeting the left sensoriMotor cortex separated by 1 week. Functional near-infrared spectroscopy hemodynamic changes were measured from the left sensoriMotor cortex during a simple finger opposition Motor Task before (Pre), immediately (T1) and 30 min after (T2) each session. The movement rates were not different between (online, offline, sham) or within (Pre, T1, T2) sessions. At T2, online HD-atDCS was associated with a significant increase (large effect size) in sensoriMotor cortex activation (Hedges g = 1.01, p
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Using of transcranial direct-current stimulation during Motor Task for a better outcome
2017Co-Authors: Pierre BessonAbstract:Historically, humans have sought various ways to improve their daily lives. With the current technological advances, this quest is facilitated, especially in the desire to increase their cognitive and / or Motor skills. Neuro imagery now makes it possible to inform the areas activated during different functional Tasks. Today, it is now possible to modulate brain activity by stimulating the brain locally with weak electrical currents. One of the most common techniques for this purpose is called tDCS for transcranial direct current stimulation. The polarity of the induced current (anodal or cathodal stimulation) allows to modulate upward or downward cortico-spinal excitability by depolarizing or hyperpolarizing the membrane of the neurons, respectively. Despite a growing interest of neuromodulation techniques via tDCS, the results reported by the scientific community are relatively heterogeneous. The work initiated at the beginning of the 2000s is called into question by current results showing a rather large inter and intra variability. This stumbling block requires the development of new protocols for the application of anodal tDCS (atDCS). In this thesis, we were interested in optimizing atDCS protocols in order to increase the persistence of the induced-neuroplastic effects and to increase the behavioral performances. Two studies were carried out in order to first reveal the impact from the Motor Task/atDCS coupling and then to highlight the cumulative effects of multiple Motor-tDCS Task sessions with priming atDCS on Motor performance. The first study through the use of near infrared spectroscopy allowed to report various hemodynamic changes subsequent to the Motor Task/atDCS coupling with respect to independent and controlled stimulation protocols. The primacy of the concomitant use of tDCS with the Motor Task was revealed by the slightest activation of the sensoriMotor cortex during stimulation and by an increased delayed cerebral activation which could represent a neuroplastic reorganization. The second study examined the effects of repeated atDCS sessions with anoadal or cathodal tDCS priming in order to improve the learning and retention gains of the sensoriMotor system. TDCS priming was more favorable for repeated atDCS sessions to generate higher Motor performances contrary to sham. The cathodal polarity produced prolonged persistence. The major findings of this work allow to support the concomitant use of atDCS with the Motor Task. Future research is needed to study the transfer of these results into the fields of coaching and rehabilitation.
Stéphane Perrey - One of the best experts on this subject based on the ideXlab platform.
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Concurrent anodal transcranial direct-current stimulation and Motor Task to influence sensoriMotor cortex activation.
Brain research, 2019Co-Authors: Pierre Besson, Makii Muthalib, Gérard Dray, John C. Rothwell, Stéphane PerreyAbstract:Abstract Functional targeting with anodal high-definition transcranial direct current stimulation (HD-atDCS) of involved brain areas during performance of a Motor Task (online) may facilitate sensoriMotor cortex neuroplasticity compared to performing the Motor Task after HD-atDCS (offline). The aim of this study was to employ functional near-infrared spectroscopy to compare the time course of Motor Task-related changes in sensoriMotor cortex activation between online and offline HD-atDCS. We hypothesized that online HD-atDCS would have a greater effect on Task-related sensoriMotor cortex activation than offline HD-atDCS. In a within-subject sham controlled and randomized study design, 9 healthy participants underwent 3 HD-atDCS sessions (online, offline and sham) targeting the left sensoriMotor cortex separated by 1 week. Functional near-infrared spectroscopy hemodynamic changes were measured from the left sensoriMotor cortex during a simple finger opposition Motor Task before (Pre), immediately (T1) and 30 min after (T2) each session. The movement rates were not different between (online, offline, sham) or within (Pre, T1, T2) sessions. At T2, online HD-atDCS was associated with a significant increase (large effect size) in sensoriMotor cortex activation (Hedges g = 1.01, p
Maureen Clerc - One of the best experts on this subject based on the ideXlab platform.
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Automatic Motor Task selection via a bandit algorithm for a brain-controlled button.
Journal of neural engineering, 2013Co-Authors: Joan Fruitet, Alexandra Carpentier, Rémi Munos, Maureen ClercAbstract:Objective. Brain–computer interfaces (BCIs) based on sensoriMotor rhythms use a variety of Motor Tasks, such as imagining moving the right or left hand, the feet or the tongue. Finding the Tasks that yield best performance, specifically to each user, is a time-consuming preliminary phase to a BCI experiment. This study presents a new adaptive procedure to automatically select (online) the most promising Motor Task for an asynchronous brain-controlled button. Approach. We develop for this purpose an adaptive algorithm UCB-classif based on the stochastic bandit theory and design an EEG experiment to test our
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Automatic Motor Task selection via a bandit algorithm for a brain-controlled button
Journal of Neural Engineering, 2013Co-Authors: Joan Fruitet, Alexandra Carpentier, Rémi Munos, Maureen ClercAbstract:Objective. Brain-computer interfaces (BCIs) based on sensoriMotor rhythms use a variety of Motor Tasks, such as imagining moving the right or left hand, the feet or the tongue. Finding the Tasks that yield best performance, specifically to each user, is a time-consuming preliminary phase to a BCI experiment. This study presents a new adaptive procedure to automatically select (online) the most promising Motor Task for an asynchronous brain-controlled button. Approach. We develop for this purpose an adaptive algorithm UCB-classif based on the stochastic bandit theory and design an EEG experiment to test our method. We compare (offline) the adaptive algorithm to a naïve selection strategy which uses uniformly distributed samples from each Task. We also run the adaptive algorithm online to fully validate the approach. Main results. By not wasting time on inefficient Tasks, and focusing on the most promising ones, this algorithm results in a faster Task selection and a more efficient use of the BCI training session. More precisely, the offline analysis reveals that the use of this algorithm can reduce the time needed to select the most appropriate Task by almost half without loss in precision, or alternatively, allow us to investigate twice the number of Tasks within a similar time span. Online tests confirm that the method leads to an optimal Task selection. Significance. This study is the first one to optimize the Task selection phase by an adaptive procedure. By increasing the number of Tasks that can be tested in a given time span, the proposed method could contribute to reducing 'BCI illiteracy'.
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Bandit Algorithms boost Brain Computer Interfaces for Motor-Task selection of a brain-controlled button
2012Co-Authors: Joan Fruitet, Alexandra Carpentier, Rémi Munos, Maureen ClercAbstract:Brain-computer interfaces (BCI) allow users to ''communicate'' with a computer without using their muscles. BCI based on sensori-Motor rhythms use imaginary Motor Tasks, such as moving the right or left hand, to send control signals. The performances of a BCI can vary greatly across users but also depend on the Tasks used, making the problem of appropriate Task selection an important issue. This study presents a new procedure to automatically select as fast as possible a discriminant Motor Task for a brain-controlled button. We develop for this purpose an adaptive algorithm, \textit{UCB-classif}, based on the stochastic bandit theory. This shortens the training stage, thereby allowing the exploration of a greater variety of Tasks. By not wasting time on inefficient Tasks, and focusing on the most promising ones, this algorithm results in a faster Task selection and a more efficient use of the BCI training session. Comparing the proposed method to the standard practice in Task selection, for a fixed time budget, \textit{UCB-classif} leads to an improved classification rate, and for a fixed classification rate, to a reduction of the time spent in training by $50\%$.
Catherine F. Siengsukon - One of the best experts on this subject based on the ideXlab platform.
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Performance on a functional Motor Task is enhanced by sleep in middle-aged and older adults.
Journal of neurologic physical therapy : JNPT, 2014Co-Authors: Alham Al-sharman, Catherine F. SiengsukonAbstract:BACKGROUND AND PURPOSE Although sleep has been shown to enhance Motor skill learning, it remains unclear whether sleep enhances learning of a functional Motor Task in middle-aged and older individuals. The purpose of this study was to examine whether sleep enhances Motor learning of a functional Motor Task in middle-aged and older adults. METHODS Twenty middle-aged and 20 older individuals were randomly assigned to either the sleep condition or the no-sleep condition. Participants in the sleep condition practiced a novel walking Task in the evening, and returned the following morning for retesting. Participants in the no-sleep condition practiced the walking Task in the morning and returned the same day in the evening for a retest. Outcome measures included time around the walking path and spatiotemporal gait parameters. RESULTS Only the middle-aged and older adults in the sleep condition demonstrated significant off-line improvement in performance, measured as a decline in time to walk around the novel path and improvement in spatiotemporal gait parameters. The middle-aged and older adults in the no-sleep condition failed to demonstrate off-line improvements in performance of this functional Task. CONCLUSIONS This is the first study to provide evidence that sleep facilitates learning a clinically relevant functional Motor Task in middle-aged and older adults. Because many neurologic conditions occur in the middle-aged and older adults and sleep issues are very prevalent in many neurologic conditions, it is imperative that physical therapists consider sleep as a factor that may impact Motor learning and recovery in these individuals. VIDEO ABSTRACT AVAILABLE (See Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A73) for more insights from the authors.
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Sleep Enhances Learning of a Functional Motor Task in Young Adults
Physical therapy, 2013Co-Authors: Alham Al-sharman, Catherine F. SiengsukonAbstract:Background Sleep has been demonstrated to enhance simple Motor skill learning “offline” in young adults. “Offline learning” refers to either the stabilization or the enhancement of a memory through the passage of time without additional practice. It remains unclear whether a functional Motor Task will benefit from sleep to produce offline Motor skill enhancement. Physical therapists often teach clients functional Motor skills; therefore, it is important to understand how sleep affects learning of these skills. Objective The purpose of this study was to determine whether sleep enhances the learning of a functional Motor Task. Design A prospective, cross-sectional, repeated-measures design was used. Methods Young participants who were healthy (N=24) were randomly assigned to either a sleep group or a no-sleep group. The sleep group practiced a novel walking Task in the evening and underwent retention testing the following morning, and the no-sleep group practiced the Task in the morning and underwent retention testing in the evening. Outcome measures included time around the walking path and spatiotemporal gait parameters. Results Only participants who slept after practicing the novel walking Task demonstrated a significant offline improvement in performance. Compared with the no-sleep group, participants in the sleep group demonstrated a significant decrease in the time around the walking path, an increase in tandem velocity, an increase in tandem step length, and a decline in tandem step time. Limitations Time-of-day effect and inability to ensure a certain amount of sleep quantity and quality of participants were limitations of the study. Conclusions This study is the first to provide evidence that sleep facilitates learning clinically relevant functional Motor Tasks. Sleep is an important factor that physical therapists should consider when teaching clients Motor skills.
Wilfried Lang - One of the best experts on this subject based on the ideXlab platform.
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Fatigue in a simple repetitive Motor Task: a combined electrophysiological and neuropsychological study.
Brain research, 2004Co-Authors: Georg Dirnberger, Gerald Lindinger, Cornelia Duregger, Eva Trettler, Wilfried LangAbstract:Fatigue is one of the most common psychophysiological symptoms that interact with the control mechanisms regulating Task behaviour. The cortical processes involved in preparation and feedback control of voluntary movement are associated with EEG activity time-locked to movement onset: a pre-movement Movement-Related Cortical Potential (MRCP) is followed by a post-movement potential (PMP). The aim of this study was to determine whether changes in subjective fatigue which arise in the course of a simple repetitive Motor Task affect cortical information processing as measured by MRCPs or PMPs. MRCPs/PMPs were recorded in 33 healthy subjects while they made 100 self-paced unilateral button presses with their left or right index finger, and then continued with the other index finger for another 100 movements. Before and after the Motor Tasks, subjective fatigue was assessed via questionnaire. (1) Subjects who reported a higher increase of fatigue when they had finished the Motor Tasks showed smaller (more negative) amplitudes of the PMP. (2) This increase of negativity was strongest during the initial part of the Tasks. (3) Physical aspects of perceived fatigue had a stronger effect on PMP amplitude than cognitive aspects. Smaller amplitudes of the PMP in more fatigued subjects might be explained by reduced attention to somatosensory feedback. Adaptation of this effect may result from more automatic performance at later stages of the Task when all subjects required a lower degree of attentional control. In conjunction with previous studies, effects of fatigue could be separated from habituation.
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High resolution spatiotemporal analysis of the contingent negative variation in simple or complex Motor Tasks and a non-Motor Task.
Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology, 2000Co-Authors: R.q. Cui, A. Egkher, Daniela Huter, Wilfried Lang, Gerald Lindinger, Lueder DeeckeAbstract:Objectives: Since the characteristics of the Bereitschaftspotential (BP) ‐ voluntary movement paradigm of internally-driven movements ‐ have been established recently by our group using high resolution DC-EEG techniques, it was of great interest to apply similar techniques to the other slow brain potential ‐ contingent negative variation (CNV) of externally-cued movements ‐ with the same Motor Tasks using the same subjects. Methods: The CNV for simple bimanual sequential movements (Task 1), complex bimanual sequential movements (Task 2) and a nonMotor condition (Task 3) was recorded on the scalp using a 64 channel DC-EEG in 16 healthy subjects, and the data were analyzed with high resolution spatiotemporal statistics and current source density (CSD). Results: (1) The CNV was distributed over frontal, frontocentral, central and centroparietal regions; a negative potential was found at the frontal pole and a positive potential was found over occipital regions. (2) CNV amplitudes were higher for Task 2 than for Task 1, and there was no late CNV for Task 3. (3) A high resolution spatiotemporal analysis revealed that during the early CNV component, statistical differences existed between the Motor Tasks (Tasks 1 and 2) and the non-Motor Task (Task 3), which occurred at frontocentral, central, centroparietal, parietal and parieto-occipital regions. During the late CNV component, additional significant differences were found not only between the Motor Tasks and the non-Motor Task but also between Motor Task 1 and Task 2 at frontocentral, central and centroparietal regions. (4) Comparison of the CNV between the frontomesial cortex (situated over the supplementary/cingulate areas, SCMA) and both lateral pre-central areas (situated over the primary Motor areas, MIs) showed that there was no statistically significant difference between the two cortical Motor areas except for the early CNV. (5) Comparison of the CNV between the 3 Tasks over the cortical Motor areas showed that there were significant differences between the Motor Tasks and the non-Motor Task regarding the auditory evoked potential (AEP) and the early CNV component, and between all 3 Tasks in the late CNV, the visual evoked potential (VEP2) and the N-P component. (6) The ranges and the densities of the CSD maps were larger and higher for complex than for simple Tasks. The current sinks of the AEP and the early CNV were located at Fz, the late CNV at FCz and surrounding regions. As to be expected, current sources of the VEPs were located at the occipital lobes. The CNV was a current sink (negative) except for the VEP’s main component which was a current source (positive). Conclusions: (1) The CNV topography over the scalp varied with the complexity of Motor Tasks and between Motor and non-Motor conditions. (2) The origin of the early CNV may rest in the frontal lobes, while the late CNV may stem from more extensive cortical areas including SCMA, MIs, etc. (3) The late CNV component is not identical with the BP. q 2000 Elsevier Science Ireland Ltd. All rights reserved.