18 results on '"Sara Tremblay"'
Search Results
2. No aftereffects of high current density 10 Hz and 20 Hz tACS on sensorimotor alpha and beta oscillations
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Hugo Théoret, Jean-François Lepage, Sara Tremblay, Dave Saint-Amour, Kevin Pacheco-Barrios, Manon Desforges, Felipe Fregni, Louis-Philippe Lafleur, and Audrey Murray
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Adult ,Male ,Adolescent ,Brain activity and meditation ,Science ,Finite Element Analysis ,Models, Neurological ,Alpha (ethology) ,Stimulation ,Electroencephalography ,Transcranial Direct Current Stimulation ,Article ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Double-Blind Method ,Oscillometry ,medicine ,Humans ,Beta (finance) ,High current density ,030304 developmental biology ,Transcranial alternating current stimulation ,Brain Mapping ,0303 health sciences ,Excitability ,Neuronal Plasticity ,Multidisciplinary ,medicine.diagnostic_test ,Oscillation ,business.industry ,Brain ,Bayes Theorem ,Healthy Volunteers ,Alpha Rhythm ,Motor cortex ,Medicine ,Female ,Sensorimotor Cortex ,Beta Rhythm ,business ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Application of transcranial alternating current stimulation (tACS) is thought to modulate ongoing brain oscillations in a frequency-dependent manner. However, recent studies report various and sometimes inconsistent results regarding its capacity to induce changes in cortical activity beyond the stimulation period. Here, thirty healthy volunteers participated in a randomized, cross-over, sham-controlled, double-blind study using EEG to measure the offline effects of tACS on alpha and beta power. Sham and high current density tACS (1 mA; 10 Hz and 20 Hz; 0.32 mA/cm2) were applied for 20 min over bilateral sensorimotor areas and EEG was recorded at rest before and after stimulation for 20 min. Bilateral tACS was not associated with significant changes in local alpha and beta power frequencies at stimulation sites (C3 and C4 electrodes). Overall, the present results fail to provide evidence that bilateral tACS with high current density applied over sensorimotor regions at 10 and 20 Hz reliably modulates offline brain oscillation power at the stimulation site. These results may have implications for the design and implementation of future protocols aiming to induce sustained changes in brain activity, including in clinical populations. more...
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- 2021
Catalog
3. Pulse width biases the balance of excitation and inhibition recruited by transcranial magnetic stimulation
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John C. Rothwell, Lorenzo Rocchi, Eleanor Wilson, Ricci Hannah, and Sara Tremblay
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Physics ,0303 health sciences ,Short-interval intracortical inhibition ,General Neuroscience ,medicine.medical_treatment ,Biophysics ,Controllable pulse parameter TMS ,lcsh:RC321-571 ,Transcranial magnetic stimulation ,03 medical and health sciences ,0302 clinical medicine ,Nuclear magnetic resonance ,medicine.anatomical_structure ,medicine ,Motor cortex ,Neurology (clinical) ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,030217 neurology & neurosurgery ,Excitation ,Pulse-width modulation ,030304 developmental biology ,Balance (ability) - Published
- 2020
4. A review of the effects of physical activity and sports concussion on brain function and anatomy
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Hugo Théoret, Alvaro Pascual-Leone, and Sara Tremblay
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medicine.medical_specialty ,Brain Structure and Function ,Context (language use) ,Physical exercise ,Grey matter ,03 medical and health sciences ,0302 clinical medicine ,Physical medicine and rehabilitation ,Physiology (medical) ,Concussion ,medicine ,Humans ,Aerobic exercise ,Neurochemistry ,Gray Matter ,Exercise ,Brain Concussion ,biology ,Athletes ,General Neuroscience ,Motor Cortex ,030229 sport sciences ,Anatomy ,medicine.disease ,biology.organism_classification ,White Matter ,Neuropsychology and Physiological Psychology ,medicine.anatomical_structure ,Athletic Injuries ,Psychology ,030217 neurology & neurosurgery - Abstract
Physical activity has been associated with widespread anatomical and functional brain changes that occur following acute exercise or, in the case of athletes, throughout life. High levels of physical activity through the practice of sports also lead to better general health and increased cognitive function. Athletes are at risk, however, of suffering a concussion, the effects of which have been extensively described for brain function and anatomy. The level to which these effects are modulated by increased levels of fitness is not known. Here, we review literature describing the effects of physical activity and sports concussions on white matter, grey matter, neurochemistry and cortical excitability. We suggest that the effects of sports concussion can be coufounded by the effects of exercise. Indeed, available data show that the brain of athletes is different from that of healthy individuals with a non-active lifestyle. As a result, sports concussions take place in a context where structural/functional plasticity has occurred prior to the concussive event. The sports concussion literature does not permit, at present, to separate the effects of intense and repeated physical activity, and the abrupt removal from such activities, from those of concussion on brain structure and function. more...
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- 2018
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5. Assessment of Effective Connectivity and Plasticity With Dual-Coil Transcranial Magnetic Stimulation
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Louis-Philippe Lafleur, Jean-François Lepage, Kevin Whittingstall, and Sara Tremblay
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0301 basic medicine ,medicine.medical_treatment ,Biophysics ,Neuroimaging ,Stimulation ,lcsh:RC321-571 ,Functional connectivity ,03 medical and health sciences ,0302 clinical medicine ,Twin coil ,Motor system ,medicine ,Humans ,Neurostimulation ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,Neuronal Plasticity ,Orientation (computer vision) ,General Neuroscience ,Motor Cortex ,Neurosciences ,Brain ,Dual coil ,Cognition ,Human brain ,Transcranial Magnetic Stimulation ,Transcranial magnetic stimulation ,030104 developmental biology ,medicine.anatomical_structure ,Paired-associative stimulation ,Neurology (clinical) ,Nerve Net ,Psychology ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Background Understanding how different brain regions interact with one another is at the heart of current endeavors in cognitive and basic neuroscience. Unlike most neuroimaging techniques, transcranial magnetic stimulation (TMS) allows the establishment of causal relationships in the study of the functional architecture of the human brain. While this tool is increasingly used to probe the functional and causal nature of the associations between brain regions, a comprehensive guide documenting the various existing stimulation protocols is currently lacking, limiting its use. Objective The main objective of the current work is to characterize the various dual-coil TMS protocols used to probe effective connectivity and plasticity within the motor system. In addition, we want to propose a short TMS battery that could be used in clinical and research settings. Method Articles using dual-coil TMS indexed in PubMed and Medline published between 1990 and 2015 were included in the review. Results A wide range of stimulation parameters has been used to probe connectivity and plasticity. However, a few protocols have been shown to produce robust effects, mostly inhibitory in nature. Conclusion Dual-coil TMS offers the distinctive opportunity to investigate effective connectivity and plasticity between different parts of the brain. Sites of stimulation, stimulation intensity, inter-stimulus interval and coil orientation are crucial factors to consider when using this technique. We propose a brief battery of tests that could be used to assess effective brain connectivity in clinical populations. more...
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- 2016
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6. Probing the effects of mild traumatic brain injury with transcranial magnetic stimulation of the primary motor cortex
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Hugo Théoret, Geneviève Lefebvre, and Sara Tremblay
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Adult ,Male ,Traumatic brain injury ,medicine.medical_treatment ,Neuroscience (miscellaneous) ,Inhibitory postsynaptic potential ,Young Adult ,Neuroplasticity ,Concussion ,Developmental and Educational Psychology ,medicine ,Humans ,Brain Concussion ,Aged ,Neuronal Plasticity ,Motor Cortex ,Middle Aged ,Evoked Potentials, Motor ,medicine.disease ,Transcranial Magnetic Stimulation ,Transcranial magnetic stimulation ,Brain Injuries ,Synaptic plasticity ,Facilitation ,Female ,Neurology (clinical) ,Primary motor cortex ,Psychology ,Neuroscience - Abstract
The present paper systematically reviews studies using transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) to assess cortical excitability, intra-cortical inhibition/facilitation and synaptic plasticity following mild traumatic brain injury (mTBI).Articles using TMS over M1 in patients with mTBI or sport-related concussion indexed in PubMed and published between 1998 and September 2014 were included in the present review.From the 17 articles that matched search criteria, results from various TMS paradigms were summarized and divided in three main areas of interest: motor cortical excitability/facilitation, motor cortical inhibition and cortical plasticity. Although studies suggest a trend of abnormal intra-cortical inhibition following mTBI, no clear and specific pattern emerges from the surveyed data.At this time and with the possible exception of intra-cortical inhibitory measures, TMS cannot reliably detect changes in M1 excitability in individuals with mTBI or a concussion at both the acute and chronic stages of injury. This may be explained by the small number of studies and large variety of stimulation parameters. Additional longitudinal and multimodal studies are needed to better understand the nature of the excitability changes that may occur within M1 following mTBI. more...
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- 2015
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7. Multimodal assessment of primary motor cortex integrity following sport concussion in asymptomatic athletes
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Vincent Beaulé, Julien Doyon, Hugo Théoret, Maryse Lassonde, Małgorzata Marjańska, Sara Tremblay, Sébastien Tremblay, and Sébastien Proulx
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Male ,medicine.medical_specialty ,Traumatic brain injury ,medicine.medical_treatment ,Football ,Glutamic Acid ,Poison control ,Asymptomatic ,Young Adult ,Neurochemical ,Physical medicine and rehabilitation ,Surveys and Questionnaires ,Physiology (medical) ,medicine ,Humans ,Brain Concussion ,gamma-Aminobutyric Acid ,Brain Mapping ,Trauma Severity Indices ,biology ,Athletes ,business.industry ,Motor Cortex ,biology.organism_classification ,medicine.disease ,Magnetic Resonance Imaging ,Transcranial Magnetic Stimulation ,Sensory Systems ,Transcranial magnetic stimulation ,medicine.anatomical_structure ,Neurology ,Athletic Injuries ,Neurology (clinical) ,Primary motor cortex ,medicine.symptom ,business ,Motor cortex - Abstract
Recent studies have shown, in asymptomatic concussed athletes, metabolic disruption in the primary motor cortex (M1) and abnormal intracortical inhibition lasting for more than six months. The present study aims to assess if these neurochemical and neurophysiological alterations are persistent and linked to M1 cortical thickness.Sixteen active football players who sustained their last concussion, on average, three years prior to testing and 14 active football players who never sustained a concussion were recruited for a single session of proton magnetic resonance spectroscopy ((1)H-MRS) and transcranial magnetic stimulation (TMS). Measures of M1 and whole brain cortical thickness were acquired, and (1)H-MRS data were acquired from left M1 using a MEGA-PRESS sequence. Cortical silent period (CSP) and long-interval intracortical inhibition (LICI) were measured with TMS applied over left M1.No significant group differences were observed for metabolic concentrations, TMS measures, and cortical thickness. However, whereas GABA and glutamate levels were positively correlated in control athletes, this relationship was absent in concussed athletes.These data suggest the general absence of neurophysiologic, neurometabolic and neuroanatomical disruptions in M1 three years following the last concussive event. However, correlational analyses suggest the presence of a slight metabolic imbalance between GABA and glutamate concentrations in the primary motor cortex of concussed athletes.The present study highlights the importance of multimodal assesments of the impacts of sport concussions. more...
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- 2014
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8. Relationship between transcranial magnetic stimulation measures of intracortical inhibition and spectroscopy measures of GABA and glutamate+glutamine
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Małgorzata Marjańska, Julien Doyon, Louis De Beaumont, Vincent Beaulé, Alvaro Pascual-Leone, Sara Tremblay, Sébastien Proulx, Hugo Théoret, and Maryse Lassonde
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Adult ,Male ,Magnetic Resonance Spectroscopy ,Physiology ,Glutamine ,medicine.medical_treatment ,Glutamic Acid ,GABAB receptor ,Inhibitory postsynaptic potential ,gamma-Aminobutyric acid ,chemistry.chemical_compound ,medicine ,Humans ,Neurotransmitter ,gamma-Aminobutyric Acid ,GABAA receptor ,General Neuroscience ,Motor Cortex ,Glutamate receptor ,Neural Inhibition ,Articles ,Glutamic acid ,Transcranial Magnetic Stimulation ,Transcranial magnetic stimulation ,nervous system ,chemistry ,Female ,Psychology ,Neuroscience ,medicine.drug - Abstract
Transcranial magnetic stimulation (TMS) can provide an index of intracortical excitability/inhibition balance. However, the neurochemical substrate of these measures remains unclear. Pharmacological studies suggest the involvement of GABAA and GABAB receptors in TMS protocols aimed at measuring intracortical inhibition, but this link remains inferential. Proton magnetic resonance spectroscopy (1H-MRS) permits measurement of GABA and glutamate + glutamine (Glx) concentrations in the human brain and might help in the direct empirical assessment of the relationship between TMS inhibitory measures and neurotransmitter concentrations. In the present study, MRS-derived relative concentrations of GABA and Glx measured in the left M1 of healthy participants were correlated with TMS measures of intracortical inhibition. Glx levels were found to correlate positively with TMS-induced silent period duration, whereas no correlation was found between GABA concentration and TMS measures. The present data demonstrate that specific TMS measures of intracortical inhibition are linked to shifts in cortical Glx, rather than GABA neurotransmitter levels. Glutamate might specifically interact with GABAB receptors, where higher MRS-derived Glx concentrations seem to be linked to higher levels of receptor activity. more...
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- 2013
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9. Anodal transcranial direct current stimulation modulates GABAB-related intracortical inhibition in the M1 of healthy individuals
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Hugo Théoret, Sara Tremblay, Jean-François Lepage, and Vincent Beaulé
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Adult ,Male ,Time Factors ,medicine.medical_treatment ,Biophysics ,Stimulation ,GABAB receptor ,Inhibitory postsynaptic potential ,Young Adult ,Humans ,Medicine ,Evoked potential ,Electrodes ,Transcranial direct-current stimulation ,Electromyography ,business.industry ,General Neuroscience ,Cortical Spreading Depression ,Motor Cortex ,Neural Inhibition ,Evoked Potentials, Motor ,Transcranial Magnetic Stimulation ,Transcranial magnetic stimulation ,Female ,Silent period ,Primary motor cortex ,business ,Neuroscience - Abstract
It is known that transcranial direct current stimulation (tDCS) can induce polarity-specific shifts in brain excitability of the primary motor cortex (M1) with anodal tDCS enhancing and cathodal tDCS reducing cortical excitability. However, less is known about its impact on specific intracortical inhibitory mechanisms, such as γ-aminobutyric acid B (GABAB)-mediated inhibition. Consequently, the aim of the present study was to assess the impact of anodal and cathodal tDCS on M1 intracortical inhibition in healthy individuals. Long-interval intracortical inhibition (LICI) and cortical silent period (CSP) duration, both presumably mediated by GABAB receptors, were assessed using transcranial magnetic stimulation immediately before and after a 20 min session of tDCS over the left M1. Anodal tDCS significantly enhanced motor evoked potential size and reduced CSP duration, whereas it had no effect on LICI. Cathodal stimulation did not significantly modulate motor evoked potential size, CSP duration or LICI. This study provides evidence that anodal tDCS, presumably by synaptic plasticity mechanisms, has a direct effect on GABAB-meditated inhibition assessed by the CSP, but not by LICI. Our results further suggest that CSP and LICI probe distinct intracortical inhibitory mechanisms as they are differentially modulated by anodal tDCS. Finally, these data may have clinical value in patients in whom a pathological increase in CSP duration is present, such as schizophrenia. more...
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- 2013
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10. Non-invasive brain stimulation as a tool to study cerebellar-M1 interactions in humans
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Sara Tremblay, Duncan Austin, Ricci Hannah, and John C. Rothwell
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0301 basic medicine ,medicine.medical_specialty ,Cerebellum ,Neurology ,Primary motor cortex ,medicine.medical_treatment ,Stimulation ,Review ,03 medical and health sciences ,0302 clinical medicine ,Theta burst stimulation ,medicine ,Non-invasive brain stimulation ,Transcranial direct-current stimulation ,Transcranial magnetic stimulation ,030104 developmental biology ,medicine.anatomical_structure ,nervous system ,Paired-associative stimulation ,Brain stimulation ,Transcranial direct current stimulation ,Neurology (clinical) ,Psychology ,Neuroscience ,030217 neurology & neurosurgery ,Motor cortex - Abstract
The recent development of non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) has allowed the non-invasive assessment of cerebellar function in humans. Early studies showed that cerebellar activity, as reflected in the excitability of the dentate-thalamo-cortical pathway, can be assessed with paired stimulation of the cerebellum and the primary motor cortex (M1) (cerebellar inhibition of motor cortex, CBI). Following this, many attempts have been made, using techniques such as repetitive TMS and transcranial electrical stimulation (TES), to modulate the activity of the cerebellum and the dentate-thalamo-cortical output, and measure their impact on M1 activity. The present article reviews literature concerned with the impact of non-invasive stimulation of cerebellum on M1 measures of excitability and “plasticity” in both healthy and clinical populations. The main conclusion from the 27 reviewed articles is that the effects of cerebellar “plasticity” protocols on M1 activity are generally inconsistent. Nevertheless, two measurements showed relatively reproducible effects in healthy individuals: reduced response of M1 to sensorimotor “plasticity” (paired-associative stimulation, PAS) and reduced CBI following repetitive TMS and TES. We discuss current challenges, such as the low power of reviewed studies, variability in stimulation parameters employed and lack of understanding of physiological mechanisms underlying CBI. more...
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- 2016
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11. The effects of bi-hemispheric M1-M1 transcranial direct current stimulation on primary motor cortex neurophysiology and metabolite concentration
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Małgorzata Marjańska, Louis-Philippe Lafleur, Hugo Théoret, Alex Latulipe-Loiselle, Julien Doyon, Sara Tremblay, Vincent Beaulé, and Sébastien Proulx
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Adult ,Male ,medicine.medical_treatment ,Metabolite ,Proton Magnetic Resonance Spectroscopy ,Pyramidal Tracts ,Glutamic Acid ,Stimulation ,Transcranial Direct Current Stimulation ,050105 experimental psychology ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Young Adult ,0302 clinical medicine ,Developmental Neuroscience ,medicine ,Humans ,0501 psychology and cognitive sciences ,gamma-Aminobutyric Acid ,Transcranial direct-current stimulation ,05 social sciences ,Glutamate receptor ,Motor Cortex ,Neurophysiology ,Evoked Potentials, Motor ,Transcranial Magnetic Stimulation ,Transcranial magnetic stimulation ,medicine.anatomical_structure ,Neurology ,chemistry ,Female ,Neurology (clinical) ,Primary motor cortex ,Psychology ,Neuroscience ,030217 neurology & neurosurgery ,Motor cortex - Abstract
PURPOSE. The aim of the present study was to assess, in healthy individuals, the impact of M1-M1 tDCS on primary motor cortex excitability using transcranial magnetic stimulation and sensorimotor metabolite concentration using (1)H-MRS. METHODS. For both experiments, each participant received the three following interventions (20 min tDCS, 1mA): left-anodal/right-cathodal, left-cathodal/right-anodal, sham. The effects of tDCS were assessed via motor evoked potentials (experiment 1) and metabolite concentrations (experiment 2) immediately after and 12 minutes following the end of stimulation and compared to baseline measurement. RESULTS. No effect of M1-M1 tDCS on corticospinal excitability was found. Similarly, M1-M1 tDCS did not significantly modulate metabolite concentrations. High inter-subject variability was noted. Response rate analysis showed a tendency towards inhibition following left-anodal/right-cathodal tDCS in 50% of participants and increased GABA levels in 45% of participants. CONCLUSION. In line with recent studies showing important inter-subject variability following M1-supraorbital tDCS, the present data show that M1-M1 stimulation is also associated with large response variability. The absence of significant effects suggests that current measures may lack sensitivity to assess changes in M1 neurophysiology and metabolism associated with M1-M1 tDCS. more...
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- 2016
12. Modulation of physiological mirror activity with transcranial direct current stimulation over dorsal premotor cortex
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Jean-François Lepage, Vincent Beaulé, Hugo Théoret, Sara Tremblay, Louis-Philippe Lafleur, and Marie Chantal Ferland
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Dorsum ,Male ,medicine.medical_treatment ,Movement ,Stimulation ,Transcranial Direct Current Stimulation ,Mirror movements ,050105 experimental psychology ,Functional Laterality ,Premotor cortex ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,medicine ,Humans ,0501 psychology and cognitive sciences ,Mirror Neurons ,Transcranial direct-current stimulation ,General Neuroscience ,05 social sciences ,Motor Cortex ,Motor control ,Hand ,medicine.anatomical_structure ,Bilateral stimulation ,Cortical network ,Female ,Psychology ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Humans have a natural tendency towards symmetrical movements, which rely on a distributed cortical network that allows for complex unimanual movements. Studies on healthy humans using rTMS have shown that disruption of this network, and particularly the dorsal premotor cortex (dPMC), can result in increased physiological mirror movements. The aim of the present set of experiments was to further investigate the role of dPMC in restricting motor output to the contralateral hand and determine whether physiological mirror movements could be decreased in healthy individuals. Physiological mirror movements were assessed before and after transcranial direct current stimulation (tDCS) over right and left dPMC in three conditions: bilateral, unilateral left and unilateral right stimulation. Mirror EMG activity was assessed immediately before, 0, 10 and 20 min after tDCS. Results show that physiological mirroring increased significantly in the hand ipsilateral to cathodal stimulation during bilateral stimulation of the dPMC, 10 and 20 min after stimulation compared to baseline. There was no significant modulation of physiological mirroring in the hand ipsilateral to anodal stimulation in the bilateral condition or following unilateral anodal or unilateral cathodal stimulation. The present data further implicate the dPMC in the control of unimanual hand movements and show that physiological mirroring can be increased but not decreased with dPMC tDCS. more...
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- 2016
13. Early non-specific modulation of corticospinal excitability during action observation
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Sara Tremblay, Jean-François Lepage, and Hugo Théoret
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Male ,Autism-spectrum quotient ,medicine.medical_specialty ,Photic Stimulation ,Movement ,medicine.medical_treatment ,Pyramidal Tracts ,Empathy quotient ,Young Adult ,Physical medicine and rehabilitation ,medicine ,Humans ,Social Behavior ,Mirror neuron ,General Neuroscience ,Motor Cortex ,Evoked Potentials, Motor ,Transcranial Magnetic Stimulation ,body regions ,Transcranial magnetic stimulation ,medicine.anatomical_structure ,Imagination ,Facilitation ,Female ,Primary motor cortex ,Psychology ,Neuroscience ,Motor cortex - Abstract
Activity of the primary motor cortex (M1) during action observation is thought to reflect motor resonance. Here, we conducted three studies using transcranial magnetic stimulation (TMS)-induced motor-evoked potentials (MEPs) of the first dorsal interosseus muscle (FDI) during action observation to determine: (i) the time course of M1 corticospinal excitability during the observation of a simple finger movement; (ii) the specificity of M1 modulation in terms of type of movement and muscle; and (iii) the relationship between M1 activity and measures of empathy and autistic traits. In a first study, we administered single-pulse TMS at 30-ms intervals during the observation of simple finger movements. Results showed enhanced corticospinal excitability occurring between 60 and 90 ms after movement onset. In a second experiment, TMS-induced MEPs were recorded from the FDI and abductor digiti minimi muscles while pulses were delivered 90 ms after movement onset during observation of simple finger movement and dot movement. Increased corticospinal excitability was restricted to finger movement and was present in both muscles. Finally, in an exploratory experiment, single-pulse TMS was administered at 30, 90 and 150 ms after movement onset, and participants were asked to complete the Empathy Quotient (EQ) and the Autism Spectrum Quotient (AQ). Correlational analysis revealed a significant link between motor facilitation at 90 ms and the EQ and AQ scores. These results suggest that corticospinal excitability modulation seen at M1 during action observation is the result of a rapid and crude automatic process, which may be related to social functioning. more...
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- 2010
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14. Theta burst stimulation to characterize changes in brain plasticity following mild traumatic brain injury: A proof-of-principle study
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Alvaro Pascual-Leone, Shahid Bashir, Marine Vernet, Hugo Theoret, Sara Tremblay, Département de Psychologie [Montréal], Université de Montréal (UdeM), and Berenson-Allen Center for Noninvansive Brain Stimulation (CNBS) more...
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Adult ,Male ,Traumatic brain injury ,medicine.medical_treatment ,CTBS ,Article ,03 medical and health sciences ,Young Adult ,[SCCO]Cognitive science ,0302 clinical medicine ,Developmental Neuroscience ,Neuroplasticity ,Concussion ,medicine ,Humans ,ComputingMilieux_MISCELLANEOUS ,030304 developmental biology ,0303 health sciences ,Neuronal Plasticity ,Electromyography ,[SCCO.NEUR]Cognitive science/Neuroscience ,Motor Cortex ,medicine.disease ,Evoked Potentials, Motor ,Transcranial Magnetic Stimulation ,Transcranial magnetic stimulation ,medicine.anatomical_structure ,Neurology ,Brain Injuries ,Synaptic plasticity ,Feasibility Studies ,Female ,[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC] ,Neurology (clinical) ,Primary motor cortex ,Psychology ,Neuroscience ,030217 neurology & neurosurgery ,[SDV.MHEP]Life Sciences [q-bio]/Human health and pathology ,Motor cortex - Abstract
Purpose: Recent studies investigating the effects of mild traumatic brain injury (mTBI) suggest the presence of unbalanced excitatory and inhibitory mechanisms within primary motor cortex (M1). Whether these abnormalities are associated with impaired synaptic plasticity remains unknown. 11 12 13 Methods: The effects of continuous theta burst stimulation (cTBS) on transcranial magnetic stimulation-induced motor evoked potentials (MEPs) were assessed on average two weeks and six weeks following mTBI in five individuals. 14 15 Results: The procedure was well-tolerated by all participants. Continuous TBS failed to induce a significant reduction of MEP amplitudes two weeks after the injury, but response to cTBS normalized six weeks following injury, as a majority of patients became asymptomatic. 16 17 18 Conclusions: These preliminary results suggest that cTBS can be used to assess M1 synaptic plasticity in subacute phase following mTBI and may provide insights into neurobiological substrates of symptoms and consequences of mTBI. 19 20 more...
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- 2015
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15. The Use of Magnetic Resonance Spectroscopy as a Tool for the Measurement of Bi-hemispheric Transcranial Electric Stimulation Effects on Primary Motor Cortex Metabolism
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Sébastien Proulx, Vincent Beaulé, Hugo Théoret, Julien Doyon, Louis Philippe Lafleur, Małgorzata Marjańska, and Sara Tremblay
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Proton Magnetic Resonance Spectroscopy ,medicine.medical_treatment ,General Chemical Engineering ,Glutamic Acid ,Transcranial Direct Current Stimulation ,gamma-Aminobutyric acid ,General Biochemistry, Genetics and Molecular Biology ,chemistry.chemical_compound ,medicine ,Humans ,Neurotransmitter ,Stroke ,gamma-Aminobutyric Acid ,Transcranial direct-current stimulation ,General Immunology and Microbiology ,business.industry ,General Neuroscience ,Motor Cortex ,Glutamate receptor ,medicine.disease ,Electric Stimulation ,Neuromodulation (medicine) ,medicine.anatomical_structure ,chemistry ,Primary motor cortex ,business ,Neuroscience ,medicine.drug ,Motor cortex - Abstract
Transcranial direct current stimulation (tDCS) is a neuromodulation technique that has been increasingly used over the past decade in the treatment of neurological and psychiatric disorders such as stroke and depression. Yet, the mechanisms underlying its ability to modulate brain excitability to improve clinical symptoms remains poorly understood 33. To help improve this understanding, proton magnetic resonance spectroscopy (1H-MRS) can be used as it allows the in vivo quantification of brain metabolites such as γ-aminobutyric acid (GABA) and glutamate in a region-specific manner 41. In fact, a recent study demonstrated that 1H-MRS is indeed a powerful means to better understand the effects of tDCS on neurotransmitter concentration 34. This article aims to describe the complete protocol for combining tDCS (NeuroConn MR compatible stimulator) with 1H-MRS at 3 T using a MEGA-PRESS sequence. We will describe the impact of a protocol that has shown great promise for the treatment of motor dysfunctions after stroke, which consists of bilateral stimulation of primary motor cortices 27,30,31. Methodological factors to consider and possible modifications to the protocol are also discussed. more...
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- 2014
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16. Interhemispheric Control of Unilateral Movement
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Sara Tremblay, Hugo Théoret, and Vincent Beaulé
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Nerve net ,Movement ,medicine.medical_treatment ,Review Article ,Corpus callosum ,050105 experimental psychology ,Lateralization of brain function ,Corpus Callosum ,lcsh:RC321-571 ,Premotor cortex ,03 medical and health sciences ,0302 clinical medicine ,Basal ganglia ,medicine ,Humans ,0501 psychology and cognitive sciences ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,Supplementary motor area ,05 social sciences ,Age Factors ,Motor Cortex ,medicine.anatomical_structure ,Neurology ,Neurology (clinical) ,Nerve Net ,Stroke recovery ,Psychology ,Neuroscience ,Psychomotor Performance ,030217 neurology & neurosurgery ,Motor cortex - Abstract
To perform strictly unilateral movements, the brain relies on a large cortical and subcortical network. This network enables healthy adults to perform complex unimanual motor tasks without the activation of contralateral muscles. However, mirror movements (involuntary movements in ipsilateral muscles that can accompany intended movement) can be seen in healthy individuals if a task is complex or fatiguing, in childhood, and with increasing age. Lateralization of movement depends on complex interhemispheric communication between cortical (i.e., dorsal premotor cortex, supplementary motor area) and subcortical (i.e., basal ganglia) areas, probably coursing through the corpus callosum (CC). Here, we will focus on transcallosal interhemispheric inhibition (IHI), which facilitates complex unilateral movements and appears to play an important role in handedness, pathological conditions such as Parkinson’s disease, and stroke recovery. more...
- Published
- 2012
17. Evidence for the specificity of intracortical inhibitory dysfunction in asymptomatic concussed athletes
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Louis De Beaumont, Sara Tremblay, Hugo Théoret, and Maryse Lassonde
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Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,Neural Conduction ,Poison control ,Stimulation ,Somatosensory system ,Asymptomatic ,Physical medicine and rehabilitation ,Evoked Potentials, Somatosensory ,medicine ,Humans ,Brain Concussion ,Analysis of Variance ,biology ,Athletes ,business.industry ,Motor Cortex ,Neural Inhibition ,biology.organism_classification ,Transcranial Magnetic Stimulation ,Electric Stimulation ,Median Nerve ,Transcranial magnetic stimulation ,Somatosensory evoked potential ,Athletic Injuries ,Neurology (clinical) ,Primary motor cortex ,medicine.symptom ,business - Abstract
Sports concussions affect thousands of individuals every year and are a major public health concern. Still, little is known about the long-term and cumulative effects of concussions on brain neurophysiology. The principal objective of this study was to investigate the long-lasting effects of multiple sports concussions on sensorimotor integration and somatosensory processing in a sample of 12 concussed athletes and 14 non-concussed athletes of similar age (mean, 23 years) and education (mean, 16 years). Right median nerve stimulation was paired with transcranial magnetic stimulation (TMS) of the left primary motor cortex to investigate sensorimotor integration with short latency afferent inhibition (SAI) and long latency afferent inhibition (LAI) at five interstimulus intervals (18, 20, 22, 100, 200 msec). Somatosensory evoked potentials (SEP) were recorded from the left centro-parietal region. We also investigated primary motor cortex inhibitory mechanisms with three TMS protocols: cortical silent period, long interval intracortical inhibition, and short interval intracortical inhibition. Motor evoked potentials were recorded from the right abductor pollicis brevis muscle. No differences were observed between groups for SAI, LAI, and SEP. However, cortical silent period duration was prolonged and long interval intracortical inhibition was enhanced in the concussed group. These findings suggest that multiple sports concussions lead to specific, long-term neurophysiological dysfunctions of intracortical inhibitory mechanisms in primary motor cortex while somatosensory processing and sensorimotor integration are spared. This study provides additional evidence for the presence of specific and stable alterations of GABA(B) receptor activity in primary motor cortex that may be of clinical value for prognosis and diagnosis. more...
- Published
- 2011
18. Action related sounds induce early and late modulations of motor cortex activity
- Author
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Dang Khoa Nguyen, Sara Tremblay, Hugo Théoret, Maryse Lassonde, François Champoux, and Jean-François Lepage
- Subjects
Auditory perception ,Visual perception ,Time Factors ,Movement ,Electroencephalography ,Brain mapping ,Fingers ,Rhythm ,Tongue ,otorhinolaryngologic diseases ,medicine ,Reaction Time ,Humans ,Child ,Evoked Potentials ,Brain Mapping ,Epilepsy ,medicine.diagnostic_test ,General Neuroscience ,Motor Cortex ,Human brain ,Electrophysiology ,medicine.anatomical_structure ,Sound ,Acoustic Stimulation ,Auditory Perception ,Female ,Psychology ,Neuroscience ,Motor cortex - Abstract
It is now well established that the human brain is endowed with a mechanism that pairs action perception with its execution. This system has been extensively studied using visual stimuli and recent evidence suggests that it is also responsive to the sound of motor actions. Here, we presented action (finger and tongue clicks) and acoustically matched sounds to investigate action-related sound processing in a 12-year-old child undergoing intracranial monitoring of epileptic seizures. Electroencephalography grids were located over a large portion of the right hemisphere, including motor cortex. Wavelet analysis carried out on electrodes overlying the functionally defined hand representation of the motor cortex revealed early (100 ms) and late (250-450 ms) decreases in mu rhythm power (12 and 20 Hz) selective for natural finger-clicks compared with control sounds. These data suggest the presence of a rapid, multimodal resonance mechanism modulating motor cortex activity. more...
- Published
- 2010
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