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Fong PY, Spampinato D, Rocchi L, Hannah R, Teng Y, Di Santo A, Shoura M, Bhatia K, Rothwell JC. Two forms of short-interval intracortical inhibition in human motor cortex. Brain Stimul 2021; 14:1340-1352. [PMID: 34481097 PMCID: PMC8460995 DOI: 10.1016/j.brs.2021.08.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 08/21/2021] [Accepted: 08/31/2021] [Indexed: 11/24/2022] Open
Abstract
Background Pulses of transcranial magnetic stimulation (TMS) with a predominantly anterior-posterior (AP) or posterior-anterior (PA) current direction over the primary motor cortex appear to activate distinct excitatory inputs to corticospinal neurons. In contrast, very few reports have examined whether the inhibitory neurons responsible for short-interval intracortical inhibition (SICI) are sensitive to TMS current direction. Objectives To investigate whether SICI evaluated with AP and PA conditioning stimuli (CSPA and CSAP) activate different inhibitory pathways. SICI was always assessed using a PA-oriented test stimulus (TSPA). Methods Using two superimposed TMS coils, CSPA and CSAP were applied at interstimulus intervals (ISI) of 1–5 ms before a TSPA, and at a range of different intensities. Using a triple stimulation design, we then tested whether SICI at ISI of 3 ms using opposite directions of CS (SICICSPA3 and SICICSAP3) interacted differently with three other forms of inhibition, including SICI at ISI of 2 ms (SICICSPA2), cerebellum-motor cortex inhibition (CBI 5 ms) and short-latency afferent inhibition (SAI 22 ms). Finally, we compared the effect of tonic and phasic voluntary contraction on SICICSPA3 and SICICSAP3. Results CSAP produced little SICI at ISIs = 1 and 2 ms. However, at ISI = 3 ms, both CSAP and CSPA were equally effective at the same percent of maximum stimulator output. Despite this apparent similarity, combining SICICSPA3 or SICICSAP3 with other forms of inhibition led to quite different results: SICICSPA3 interacted in complex ways with CBI, SAI and SICICSPA2, whereas the effect of SICICSAP3 appeared to be quite independent of them. Although SICICSPA and SICICSAP were both reduced by the same amount during voluntary tonic contraction compared with rest, in a simple reaction time task SICICSAP was disinhibited much earlier following the imperative signal than SICICSPA. Conclusions SICICSPA appears to activate a different inhibitory pathway to that activated by SICICSAP. The difference is behaviourally relevant since the pathways are controlled differently during volitional contraction. The results may explain some previous pathological data and open the possibility of testing whether these pathways are differentially recruited in a range of tasks. Opposite directions of conditioning stimulus (CS) used to suppress MEPs evoked by a conventional test stimulus. Different directions of CS have different time courses of short-interval intracortical inhibition (SICI). They also interact differently with short-latency afferent inhibition and with cerebellar inhibition. They are differently affected in a reaction time task. We suggest there are two forms of SICI in motor cortex.
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Affiliation(s)
- Po-Yu Fong
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, UK; Division of Movement Disorders, Department of Neurology and Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan City, Taiwan; Medical School, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
| | - Danny Spampinato
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, UK; Non-invasive Brain Stimulation Unit, IRCCS Santa Lucia Foundation, Via Ardeatina 306/354, 00142, Rome, Italy
| | - Lorenzo Rocchi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, UK; Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
| | - Ricci Hannah
- Department of Psychology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Yinghui Teng
- Division of Biosciences, University College London, London, UK
| | - Alessandro Di Santo
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, UK; Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Mohamed Shoura
- Department of Neurology, Heliopolis and Al Azhar University Hospitals, Cairo, Egypt
| | - Kailash Bhatia
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - John C Rothwell
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, UK
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Advanced TMS approaches to probe corticospinal excitability during action preparation. Neuroimage 2020; 213:116746. [DOI: 10.1016/j.neuroimage.2020.116746] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/02/2020] [Accepted: 03/13/2020] [Indexed: 12/13/2022] Open
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Hendy AM, Ekblom MM, Latella C, Teo WP. Investigating the effects of muscle contraction and conditioning stimulus intensity on short-interval intracortical inhibition. Eur J Neurosci 2019; 50:3133-3140. [PMID: 31199534 DOI: 10.1111/ejn.14488] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/14/2019] [Accepted: 05/22/2019] [Indexed: 12/14/2022]
Abstract
A reduction in short-interval intracortical inhibition (SICI) has been shown to accompany acute or chronic resistance exercise; however, little is known about how SICI is modulated under different contraction intensities. Therefore, the purpose of this study was to assess the effect of muscle contraction and conditioning stimulus intensity on the modulation of SICI. Single- and paired-pulse transcranial magnetic stimulation was applied to the primary motor cortex (M1), and motor evoked potentials (MEPs) were recorded from the biceps brachii in 16 adults (10M/6F). A conditioning-test stimulus paradigm (3 ms inter-stimulus intervals) was delivered during 10%, 20%, 40% and 75% of maximal voluntary isometric contraction (MVIC). At each force level, conditioning stimulus intensities of 60%, 70% and 80% of active motor threshold (AMT) were tested. Single-pulse MEPs were expressed as a proportion of the maximal muscle compound action potential, while SICI was quantified as a ratio of the unconditioned MEP. MEP amplitude increased with force output, with the greatest increase at 75% of MVIC. A reduction in SICI was observed from 40% to 75% of MVIC, but not 10%-40% of MVIC. There was no significant interaction between conditioning stimulus intensity and force level. The conditioning stimulus intensity (60%, 70% or 80% of AMT) did not alter the modulation of SICI. SICI was reduced at 75% of MVIC compared with the lower force outputs, and the magnitude of SICI in individual participants at different force outputs was not related. The findings suggest that strong muscle contractions are accompanied by less inhibition, which may have implications for neuroplasticity in exercise interventions.
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Affiliation(s)
- Ashlee M Hendy
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition, Deakin University, Geelong, Victoria, Australia
| | - Maria M Ekblom
- The Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Christopher Latella
- Centre for Exercise and Sports Science Research (CESSR), School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Wei-Peng Teo
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition, Deakin University, Geelong, Victoria, Australia
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4
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Alcock LR, Spence AJ, Lockyer EJ, Button DC, Power KE. Short-interval intracortical inhibition to the biceps brachii is present during arm cycling but is not different than a position- and intensity-matched tonic contraction. Exp Brain Res 2019; 237:2145-2154. [DOI: 10.1007/s00221-019-05579-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 06/08/2019] [Indexed: 10/26/2022]
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5
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Suran T, Rumiati RI, Piretti L. The contribution of the left inferior frontal gyrus in affective processing of social groups. Cogn Neurosci 2019; 10:186-195. [PMID: 30913979 DOI: 10.1080/17588928.2019.1593127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We investigated the contribution of the pars opercularis of the left inferior frontal gyrus (LIFGop) in representing knowledge about social groups. We asked healthy individuals to categorize words preceded by semantically congruent or incongruent primes while stimulating the LIFGop. Previous studies showing an involvement of the LIFGop both in processing social stimuli and negative valence words led us to predict that its stimulation would affect responses to negative social category words. Compared to the Vertex as control site, the stimulation of the LIFGop increased the speed of categorization of negative social groups, and disrupted the semantic priming effect for negative words overall. Within the framework of recent theories of semantic memory, we argue that the present results provide initial evidence of the representation of social groups being characterized by affective properties, whose processing is supported by the LIFGop.
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Affiliation(s)
| | | | - Luca Piretti
- a Area of Neuroscience, SISSA , Trieste , Italy.,c Department of Psychology and Cognitive Sciences, University of Trento , Rovereto , Italy.,d Fondazione ONLUS Marica De Vincenzi , Rovereto , Italy
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Ruddy K, Balsters J, Mantini D, Liu Q, Kassraian-Fard P, Enz N, Mihelj E, Subhash Chander B, Soekadar SR, Wenderoth N. Neural activity related to volitional regulation of cortical excitability. eLife 2018; 7:e40843. [PMID: 30489255 PMCID: PMC6294548 DOI: 10.7554/elife.40843] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/26/2018] [Indexed: 12/26/2022] Open
Abstract
To date there exists no reliable method to non-invasively upregulate or downregulate the state of the resting human motor system over a large dynamic range. Here we show that an operant conditioning paradigm which provides neurofeedback of the size of motor evoked potentials (MEPs) in response to transcranial magnetic stimulation (TMS), enables participants to self-modulate their own brain state. Following training, participants were able to robustly increase (by 83.8%) and decrease (by 30.6%) their MEP amplitudes. This volitional up-versus down-regulation of corticomotor excitability caused an increase of late-cortical disinhibition (LCD), a TMS derived read-out of presynaptic GABAB disinhibition, which was accompanied by an increase of gamma and a decrease of alpha oscillations in the trained hemisphere. This approach paves the way for future investigations into how altered brain state influences motor neurophysiology and recovery of function in a neurorehabilitation context.
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Affiliation(s)
- Kathy Ruddy
- Neural Control of Movement LabETH ZürichZürichSwitzerland
- Institute of NeuroscienceTrinity College DublinDublinIreland
| | - Joshua Balsters
- Neural Control of Movement LabETH ZürichZürichSwitzerland
- Department of PsychologyRoyal Holloway University of LondonLondonUnited Kingdom
| | - Dante Mantini
- Neural Control of Movement LabETH ZürichZürichSwitzerland
- Movement Control and Neuroplasticity Research GroupKU LeuvenLeuvenBelgium
| | - Quanying Liu
- Neural Control of Movement LabETH ZürichZürichSwitzerland
- Movement Control and Neuroplasticity Research GroupKU LeuvenLeuvenBelgium
| | | | - Nadja Enz
- Neural Control of Movement LabETH ZürichZürichSwitzerland
| | - Ernest Mihelj
- Neural Control of Movement LabETH ZürichZürichSwitzerland
| | | | - Surjo R Soekadar
- Applied Neurotechnology LaboratoryUniversity of TübingenTübingenGermany
- Clinical Neurotechnology Laboratory, Neuroscience Research Center (NWFZ), Department of Psychiatry and PsychotherapyCharité – University Medicine BerlinBerlinGermany
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Kalmar JM. On task: Considerations and future directions for studies of corticospinal excitability in exercise neuroscience and related disciplines. Appl Physiol Nutr Metab 2018; 43:1113-1121. [DOI: 10.1139/apnm-2018-0123] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Over the last few decades, transcranial magnetic stimulation (TMS) has emerged as a conventional laboratory technique in human neurophysiological research. Exercise neuroscientists have used TMS to study central nervous system contributions to fatigue, training, and performance in health, injury, and disease. In such studies, corticospinal excitability is often assessed at rest or during simple isometric tasks with the implication that the results may be extrapolated to more functional and complex movement outside of the laboratory. However, the neural mechanisms that influence corticospinal excitability are both state- and task-dependent. Furthermore, there are many sites of modulation along the pathway from the motor cortex to the muscle; a fact that is somewhat obscured by the all-encompassing and poorly defined term “corticospinal excitability”. Therefore, the tasks we use to assess corticospinal excitability and the conclusions that we draw from such a global measure of the motor pathway must be taken into consideration. The overall objective of this review is to highlight the task-dependent nature of corticospinal excitability and the tools used to assess modulation at cortical and spinal sites of modulation. By weighing the advantages and constraints of conventional approaches to studying corticospinal excitability, and considering some new and novel approaches, we will continue to advance our understanding of the neural control of movement during exercise.
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Affiliation(s)
- Jayne M. Kalmar
- Wilfrid Laurier University, Department of Kinesiology and Physical Education, Waterloo, ON N2L 3C5, Canada
- Wilfrid Laurier University, Department of Kinesiology and Physical Education, Waterloo, ON N2L 3C5, Canada
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8
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Vallence AM, Smalley E, Drummond PD, Hammond GR. Long-interval intracortical inhibition is asymmetric in young but not older adults. J Neurophysiol 2017. [PMID: 28637819 DOI: 10.1152/jn.00794.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aging is typically accompanied by a decline in manual dexterity and handedness; the dominant hand executes tasks of manual dexterity more quickly and accurately than the nondominant hand in younger adults, but this advantage typically declines with age. Age-related changes in intracortical inhibitory processes might play a role in the age-related decline in manual dexterity. Long-interval intracortical inhibition (LICI) is asymmetric in young adults, with more sensitive and more powerful LICI circuits in the dominant hemisphere than in the nondominant hemisphere. Here we investigated whether the hemispheric asymmetry in LICI in younger adults persists in healthy older adults. Paired-pulse transcranial magnetic stimulation was used to measure LICI in the dominant and nondominant hemispheres of younger and older adults; LICI stimulus-response curves were obtained by varying conditioning stimulus intensity at two different interstimulus intervals [100 ms (LICI100) and 150 ms]. We have replicated the finding that LICI100 circuits are more sensitive and more powerful in the dominant than the nondominant hemisphere of young adults and extend this finding to show that the hemispheric asymmetry in LICI100 is lost with age. In the context of behavioral observations showing that dominant hand movements in younger adults are more fluent than nondominant hand movements in younger adults and dominant hand movements in older adults, we speculate a role of LICI100 in the age-related decline in manual dexterity.NEW & NOTEWORTHY In younger adults, more sensitive and more powerful long-interval intracortical inhibitory circuits are evident in the hemisphere controlling the more dexterous hand; this is not the case in older adults, for whom long-interval intracortical inhibitory circuits are symmetric and more variable than in younger adults. We speculate that the highly sensitive and powerful long-interval intracortical inhibition circuits in the dominant hemisphere play a role in manual dexterity.
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Affiliation(s)
- A-M Vallence
- School of Psychology and Exercise Science, Murdoch University, Murdoch, Australia; and
| | - E Smalley
- School of Psychology and Exercise Science, Murdoch University, Murdoch, Australia; and
| | - P D Drummond
- School of Psychology and Exercise Science, Murdoch University, Murdoch, Australia; and
| | - G R Hammond
- School of Psychology, The University of Western Australia, Crawley, Australia
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9
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Chong BWX, Stinear CM. Modulation of motor cortex inhibition during motor imagery. J Neurophysiol 2017; 117:1776-1784. [PMID: 28123007 DOI: 10.1152/jn.00549.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 01/23/2017] [Accepted: 01/23/2017] [Indexed: 11/22/2022] Open
Abstract
Motor imagery (MI) is similar to overt movement, engaging common neural substrates and facilitating the corticomotor pathway; however, it does not result in excitatory descending motor output. Transcranial magnetic stimulation (TMS) can be used to assess inhibitory networks in the primary motor cortex via measures of 1-ms short-interval intracortical inhibition (SICI), long-interval intracortical inhibition (LICI), and late cortical disinhibition (LCD). These measures are thought to reflect extrasynaptic GABAA tonic inhibition, postsynaptic GABAB inhibition, and presynaptic GABAB disinhibition, respectively. The behavior of 1-ms SICI, LICI, and LCD during MI has not yet been explored. This study aimed to investigate how 1-ms SICI, LICI, and LCD are modulated during MI and voluntary relaxation (VR) of a target muscle. Twenty-five healthy young adults participated. TMS was used to assess nonconditioned motor evoked potential (MEP) amplitude, 1-ms SICI, 100- (LICI100) and 150-ms LICI, and LCD in the right abductor pollicis brevis (APB) and right abductor digiti minimi during rest, MI, and VR of the hand. Compared with rest, MEP amplitudes were facilitated in APB during MI. SICI was not affected by task or muscle. LICI100 decreased in both muscles during VR but not MI, whereas LCD was recruited in both muscles during both tasks. This indicates that VR modulates postsynaptic GABAB inhibition, whereas both tasks modulate presynaptic GABAB inhibition in a non-muscle-specific way. This study highlights further neurophysiological parallels between actual and imagined movement, which may extend to voluntary relaxation.NEW & NOTEWORTHY This is the first study to investigate how 1-ms short-interval intracortical inhibition, long-interval intracortical inhibition, and late cortical disinhibition are modulated during motor imagery and voluntary muscle relaxation. We present novel findings of decreased 100-ms long-interval intracortical inhibition during voluntary muscle relaxation and increased late cortical disinhibition during both motor imagery and voluntary muscle relaxation.
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Affiliation(s)
| | - Cathy M Stinear
- Department of Medicine, University of Auckland, Auckland, New Zealand
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Duque J, Greenhouse I, Labruna L, Ivry RB. Physiological Markers of Motor Inhibition during Human Behavior. Trends Neurosci 2017; 40:219-236. [PMID: 28341235 DOI: 10.1016/j.tins.2017.02.006] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 01/25/2023]
Abstract
Transcranial magnetic stimulation (TMS) studies in humans have shown that many behaviors engage processes that suppress excitability within the corticospinal tract. Inhibition of the motor output pathway has been extensively studied in the context of action stopping, where a planned movement needs to be abruptly aborted. Recent TMS work has also revealed markers of motor inhibition during the preparation of movement. Here, we review the evidence for motor inhibition during action stopping and action preparation, focusing on studies that have used TMS to monitor changes in the excitability of the corticospinal pathway. We discuss how these physiological results have motivated theoretical models of how the brain selects actions, regulates movement initiation and execution, and switches from one state to another.
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Affiliation(s)
- Julie Duque
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.
| | - Ian Greenhouse
- Department of Psychology, University of California, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - Ludovica Labruna
- Department of Psychology, University of California, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - Richard B Ivry
- Department of Psychology, University of California, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
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Opie GM, Rogasch NC, Goldsworthy MR, Ridding MC, Semmler JG. Investigating TMS–EEG Indices of Long-Interval Intracortical Inhibition at Different Interstimulus Intervals. Brain Stimul 2017; 10:65-74. [DOI: 10.1016/j.brs.2016.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 08/02/2016] [Accepted: 08/06/2016] [Indexed: 10/21/2022] Open
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Abstract
Preparing actions requires the operation of several cognitive control processes that influence the state of the motor system to ensure that the appropriate behavior is ultimately selected and executed. For example, some form of competition resolution ensures that the right action is chosen among alternatives, often in the presence of conflict; at the same time, impulse control ought to be deployed to prevent premature responses. Here we review how state-changes in the human motor system during action preparation can be studied through motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation over the contralateral primary motor cortex (M1). We discuss how the physiological fingerprints afforded by MEPs have helped to decompose some of the dynamic and effector-specific influences on the motor system during action preparation. We focus on competition resolution, conflict and impulse control, as well as on the influence of higher cognitive decision–related variables. The selected examples demonstrate the usefulness of MEPs as physiological readouts for decomposing the influence of distinct, but often overlapping, control processes on the human motor system during action preparation.
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Affiliation(s)
- Sven Bestmann
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London, London, UK
| | - Julie Duque
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
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