scholarly journals The primary motor cortex is critical for the retention of implicit sensorimotor adaptation

2016 ◽  
Author(s):  
Li-Ann Leow ◽  
Welber Marinovic ◽  
Timothy J Carroll ◽  
Stephan Riek
Keyword(s):  
Motor Cortex ◽  
Implicit Learning ◽  
Visual Feedback ◽  
Primary Motor Cortex ◽  
Single Pulse ◽  
Sensorimotor Adaptation ◽  
List Type ◽  
Movement Preparation ◽  
Implicit Processes

AbstractSensorimotor adaptation, or adaptation of movements to external perturbations, is thought to involve the primary motor cortex (M1). In addition to implicit error-driven remapping, explicit re-aiming strategies also contribute to sensorimotor adaptation. However, no studies to date have examined the role of M1 in implicit learning in isolation from explicit strategies. Because the application of explicit strategies requires time, it is possible to emphasise implicit learning by controlling the time available to prepare movement. Here, we examined the role of M1’s role in implicit adaptation to rotated visual feedback whilst suppressing the use of explicit re-aiming strategies by limiting movement preparation times to less than 350ms. Perturbing M1 activity via single-pulse TMS during adaptation to a 30 ° rotation of visual feedback did not alter the rate or extent of error compensation, but elicited poorer retention in post-adaptation trials with no perturbation. This work shows that M1 is critical in the retention of new visuomotor maps as a result of implicit adaptation to a perturbation in sensory feedback when strategic error correction processes are suppressed.HighlightsAdaptation of movements to perturbations occurs through explicit and implicit processes.Here, explicit strategies were suppressed by shortening movement preparation time.Perturbing motor cortex (M1) with TMS selectively impaired retention but not acquisition of sensorimotor adaptation.M1 plays a crucial role in retention of sensorimotor adaptation obtained via implicit learning.

scholarly journals Competition, Conflict and Change of Mind: A Role of GABAergic Inhibition in the Primary Motor Cortex

2022 ◽  
Vol 15 ◽  
Author(s):  
Bastien Ribot ◽  
Aymar de Rugy ◽  
Nicolas Langbour ◽  
Anne Duron ◽  
Michel Goillandeau ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Silent Period ◽  
Single Pulse ◽  
Electromyographic Activity ◽  
Continuous Control ◽  
Gabaergic Inhibition ◽  
Inhibitory Mechanisms ◽  
Post Onset

Deciding between different voluntary movements implies a continuous control of the competition between potential actions. Many theories postulate a leading role of prefrontal cortices in this executive function, but strong evidence exists that a motor region like the primary motor cortex (M1) is also involved, possibly via inhibitory mechanisms. This was already shown during the pre-movement decision period, but not after movement onset. For this pilot experiment we designed a new task compatible with the dynamics of post-onset control to study the silent period (SP) duration, a pause in electromyographic activity after single-pulse transcranial magnetic stimulation that reflects inhibitory mechanisms. A careful analysis of the SP during the ongoing movement indicates a gradual increase in inhibitory mechanisms with the level of competition, consistent with an increase in mutual inhibition between alternative movement options. However, we also observed a decreased SP duration for high-competition trials associated with change-of-mind inflections in their trajectories. Our results suggest a new post-onset adaptive process that consists in a transient reduction of GABAergic inhibition within M1 for highly conflicting situations. We propose that this reduced inhibition softens the competition between concurrent motor options, thereby favoring response vacillation, an adaptive strategy that proved successful at improving behavioral performance.

scholarly journals Online and offline effects of transcranial alternating current stimulation of the primary motor cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ivan Pozdniakov ◽  
Alicia Nunez Vorobiova ◽  
Giulia Galli ◽  
Simone Rossi ◽  
Matteo Feurra
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Random Noise ◽  
Single Pulse ◽  
Alternating Current ◽  
Online Application ◽  
Transcranial Random Noise Stimulation ◽  
Transcranial Alternating Current Stimulation

AbstractTranscranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that allows interaction with endogenous cortical oscillatory rhythms by means of external sinusoidal potentials. The physiological mechanisms underlying tACS effects are still under debate. Whereas online (e.g., ongoing) tACS over the motor cortex induces robust state-, phase- and frequency-dependent effects on cortical excitability, the offline effects (i.e. after-effects) of tACS are less clear. Here, we explored online and offline effects of tACS in two single-blind, sham-controlled experiments. In both experiments we used neuronavigated transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) as a probe to index changes of cortical excitability and delivered M1 tACS at 10 Hz (alpha), 20 Hz (beta) and sham (30 s of low-frequency transcranial random noise stimulation; tRNS). Corticospinal excitability was measured by single pulse TMS-induced motor evoked potentials (MEPs). tACS was delivered online in Experiment 1 and offline in Experiment 2. In Experiment 1, the increase of MEPs size was maximal with the 20 Hz stimulation, however in Experiment 2 neither the 10 Hz nor the 20 Hz stimulation induced tACS offline effects. These findings support the idea that tACS affects cortical excitability only during online application, at least when delivered on the scalp overlying M1, thereby contributing to the development of effective protocols that can be applied to clinical populations.

scholarly journals Role of cutaneous and proprioceptive inputs in sensorimotor integration and plasticity occurring in the facial primary motor cortex

2020 ◽  
Vol 598 (4) ◽  
pp. 839-851 ◽  
Author(s):  
Giovanna Pilurzi ◽  
Francesca Ginatempo ◽  
Beniamina Mercante ◽  
Luigi Cattaneo ◽  
Giovanni Pavesi ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Sensorimotor Integration ◽  
Primary Motor Cortex ◽  
Proprioceptive Inputs

scholarly journals Corticospinal excitability underlying digit force planning for grasping in humans

2014 ◽  
Vol 111 (12) ◽  
pp. 2560-2569 ◽  
Author(s):  
Pranav Parikh ◽  
Marco Davare ◽  
Patrick McGurrin ◽  
Marco Santello
Keyword(s):  
Primary Motor Cortex ◽  
Single Pulse ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Reach To Grasp ◽  
Grasp Planning ◽  
Sensorimotor Memory ◽  
Force Planning ◽  
Intracortical Inhibition And Facilitation

Control of digit forces for grasping relies on sensorimotor memory gained from prior experience with the same or similar objects and on online sensory feedback. However, little is known about neural mechanisms underlying digit force planning. We addressed this question by quantifying the temporal evolution of corticospinal excitability (CSE) using single-pulse transcranial magnetic stimulation (TMS) during two reach-to-grasp tasks. These tasks differed in terms of the magnitude of force exerted on the same points on the object to isolate digit force planning from reach and grasp planning. We also addressed the role of intracortical circuitry within primary motor cortex (M1) by quantifying the balance between short intracortical inhibition and facilitation using paired-pulse TMS on the same tasks. Eighteen right-handed subjects were visually cued to plan digit placement at predetermined locations on the object and subsequently to exert either negligible force (“low-force” task, LF) or 10% of their maximum pinch force (“high-force” task, HF) on the object. We found that the HF task elicited significantly smaller CSE than the LF task, but only when the TMS pulse coincided with the signal to initiate the reach. This force planning-related CSE modulation was specific to the muscles involved in the performance of both tasks. Interestingly, digit force planning did not result in modulation of M1 intracortical inhibitory and facilitatory circuitry. Our findings suggest that planning of digit forces reflected by CSE modulation starts well before object contact and appears to be driven by inputs from frontoparietal areas other than M1.

Role of Voluntary Drive in Encoding an Elementary Motor Memory

2005 ◽  
Vol 93 (2) ◽  
pp. 1099-1103 ◽  
Author(s):  
Alain Kaelin-Lang ◽  
Lumy Sawaki ◽  
Leonardo G. Cohen
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Motor Memory ◽  
Motor Drive ◽  
Motor Training ◽  
Corticomotor Excitability ◽  
Proprioceptive Input ◽  
Active Training ◽  
Passive Movements

Motor training consisting of repetitive thumb movements results in encoding of motor memories in the primary motor cortex. It is not known if proprioceptive input originating in the training movements is sufficient to produce this effect. In this study, we compared the ability of training consisting of voluntary (active) and passively-elicited (passive) movements to induce this form of plasticity. Active training led to successful encoding accompanied by characteristic changes in corticomotor excitability, while passive training did not. These results support a pivotal role for voluntary motor drive in coding motor memories in the primary motor cortex.

scholarly journals Chronic low-frequency rTMS of primary motor cortex diminishes exercise training-induced gains in maximal voluntary force in humans

2009 ◽  
Vol 106 (2) ◽  
pp. 403-411 ◽  
Author(s):  
Tibor Hortobágyi ◽  
Sarah Pirio Richardson ◽  
Mikhael Lomarev ◽  
Ejaz Shamim ◽  
Sabine Meunier ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Motor Evoked Potential ◽  
Single Pulse ◽  
Compound Action Potential ◽  
Voluntary Contraction ◽  
Maximal Voluntary Force ◽  
Resting Motor Threshold

Although there is consensus that the central nervous system mediates the increases in maximal voluntary force (maximal voluntary contraction, MVC) produced by resistance exercise, the involvement of the primary motor cortex (M1) in these processes remains controversial. We hypothesized that 1-Hz repetitive transcranial magnetic stimulation (rTMS) of M1 during resistance training would diminish strength gains. Forty subjects were divided equally into five groups. Subjects voluntarily (Vol) abducted the first dorsal interosseus (FDI) (5 bouts × 10 repetitions, 10 sessions, 4 wk) at 70–80% MVC. Another group also exercised but in the 1-min-long interbout rest intervals they received rTMS [Vol+rTMS, 1 Hz, FDI motor area, 300 pulses/session, 120% of the resting motor threshold (rMT)]. The third group also exercised and received sham rTMS (Vol+Sham). The fourth group received only rTMS (rTMS_only). The 37.5% and 33.3% gains in MVC in Vol and Vol+Sham groups, respectively, were greater ( P = 0.001) than the 18.9% gain in Vol+rTMS, 1.9% in rTMS_only, and 2.6% in unexercised control subjects who received no stimulation. Acutely, within sessions 5 and 10, single-pulse TMS revealed that motor-evoked potential size and recruitment curve slopes were reduced in Vol+rTMS and rTMS_only groups and accumulated to chronic reductions by session 10. There were no changes in rMT, maximum compound action potential amplitude (Mmax), and peripherally evoked twitch forces in the trained FDI and the untrained abductor digiti minimi. Although contributions from spinal sources cannot be excluded, the data suggest that M1 may play a role in mediating neural adaptations to strength training.

Cerebral Blood-Flow Changes Induced by Paired-Pulse Transcranial Magnetic Stimulation of the Primary Motor Cortex

2001 ◽  
Vol 85 (6) ◽  
pp. 2624-2629 ◽  
Author(s):  
A. P. Strafella ◽  
T. Paus
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Single Pulse ◽  
Paired Pulse ◽  
Positive Correlation

Positron emission tomography (PET) was used to assess changes in regional cerebral blood flow (CBF) induced by paired-pulse transcranial magnetic stimulation (TMS) of primary motor cortex (M1). The study was performed in eight normal volunteers using two Magstim-200 stimulators linked with a Bistim module. A circular TMS coil was held in the scanner by a mechanical arm and located over the left M1. Surface electrodes were used to record motor evoked potentials (MEPs) from the contralateral first dorsal interosseous muscle (FDI). Cortical excitability was evaluated in the relaxed FDI using a paired conditioning-test stimulus paradigm with two interstimulus intervals (ISIs): 3 and 12 ms. The subjects were scanned three times during each of the following four conditions: 1) baseline with no TMS (BASE); 2) single-pulse TMS (TMSsing); 3) 3-ms paired-pulse TMS (TMS3); and 4) 12-ms paired-pulse TMS (TMS12). CBF and peak-to-peak MEP amplitudes were measured over each 60-s scanning period. To assess TMS-induced changes in CBF, a t-statistic map was generated by first subtracting the single-pulse TMS condition from the 3- and 12-ms paired-pulse TMS conditions and then correlating the CBF differences, respectively, with the amount of suppression and facilitation of the EMG responses. A significant positive correlation was observed between the CBF difference (TMS3-TMSsing) and the amount of suppression of EMG response, as well as between the CBF difference (TMS12-TMSsing) and the amount of facilitation of EMG response. This positive correlation was observed in the left M1, left lateral premotor cortex, and right M1 in the case of 3-ms paired-pulse TMS, but only in the left M1 in the case of 12-ms paired-pulse TMS. The above pattern of CBF response to paired-pulse TMS supports the possibility that suppression and facilitation of the EMG response are mediated by different populations of cortical interneurons.

scholarly journals The Role of Human Primary Motor Cortex in the Production of Skilled Finger Sequences

2018 ◽  
Vol 38 (6) ◽  
pp. 1430-1442 ◽  
Author(s):  
Atsushi Yokoi ◽  
Spencer A. Arbuckle ◽  
Jörn Diedrichsen
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex

scholarly journals Dexterous Object Manipulation Requires Context-Dependent Sensorimotor Cortical Interactions in Humans

2019 ◽  
Vol 30 (5) ◽  
pp. 3087-3101 ◽  
Author(s):  
Pranav J Parikh ◽  
Justin M Fine ◽  
Marco Santello
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Object Manipulation ◽  
Storage And Retrieval ◽  
Relative Contribution ◽  
Contact Points ◽  
Behavioral Studies ◽  
Online Feedback ◽  
Digit Position

Abstract Dexterous object manipulation is a hallmark of human evolution and a critical skill for everyday activities. A previous work has used a grasping context that predominantly elicits memory-based control of digit forces by constraining where the object should be grasped. For this “constrained” grasping context, the primary motor cortex (M1) is involved in storage and retrieval of digit forces used in previous manipulations. In contrast, when choice of digit contact points is allowed (“unconstrained” grasping), behavioral studies revealed that forces are adjusted, on a trial-to-trial basis, as a function of digit position. This suggests a role of online feedback of digit position for force control. However, despite the ubiquitous nature of unconstrained hand–object interactions in activities of daily living, the underlying neural mechanisms are unknown. Using noninvasive brain stimulation, we found the role of primary motor cortex (M1) and somatosensory cortex (S1) to be sensitive to grasping context. In constrained grasping, M1 but not S1 is involved in storing and retrieving learned digit forces and position. In contrast, in unconstrained grasping, M1 and S1 are involved in modulating digit forces to position. Our findings suggest that the relative contribution of memory and online feedback modulates sensorimotor cortical interactions for dexterous manipulation.

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