scholarly journals The fall and rise of corticomotor excitability with cancellation and reinitiation of prepared action

2014 ◽  
Vol 112 (11) ◽  
pp. 2707-2717 ◽  
Author(s):  
H. J. MacDonald ◽  
J. P. Coxon ◽  
C. M. Stinear ◽  
W. D. Byblow
Keyword(s):  
Motor Behavior ◽  
Motor Evoked Potentials ◽  
Threshold Model ◽  
Intracortical Inhibition ◽  
Initial Increase ◽  
Delayed Response ◽  
Corticomotor Excitability ◽  
Left Hand ◽  
Human Participants ◽  
Response Task

The sudden cancellation of a motor action, known as response inhibition (RI), is fundamental to human motor behavior. The behavioral selectivity of RI can be studied by cueing cancellation of only a subset of a planned response, which markedly delays the remaining executed components. The present study examined neurophysiological mechanisms that may contribute to these delays. In two experiments, human participants received single- and paired-pulse transcranial magnetic stimulation while performing a bimanual anticipatory response task. Participants performed most trials bimanually (Go trials) and were sometimes cued to cancel the response with one hand while responding with the other (Partial trials). Motor evoked potentials were recorded from left first dorsal interosseous (FDI) as a measure of corticomotor excitability (CME) during Go and Partial trials. CME was temporally modulated during Partial trials in a manner that reflected anticipation, suppression, and subsequent initiation of a reprogrammed response. There was an initial increase in CME, followed by suppression 175 ms after the stop signal, even though the left hand was not cued to stop. A second increase in excitability occurred prior to the (delayed) response. We propose an activation threshold model to account for nonselective RI. To investigate the inhibitory component of our model, we investigated short-latency intracortical inhibition (sICI), but results indicated that sICI cannot fully explain the observed temporal modulation of CME. These neurophysiological and behavioural results indicate that the default mode for reactive partial cancellation is suppression of a unitary response, followed by response reinitiation with an inevitable time delay.

scholarly journals Inhibition during response preparation is sensitive to response complexity

2015 ◽  
Vol 113 (7) ◽  
pp. 2792-2800 ◽  
Author(s):  
Ian Greenhouse ◽  
Dylan Saks ◽  
Timothy Hoang ◽  
Richard B. Ivry
Keyword(s):  
Primary Motor Cortex ◽  
Response Selection ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Delayed Response ◽  
Response Preparation ◽  
Response Hand ◽  
Left Hand ◽  
Movement Complexity ◽  
Response Task

Motor system excitability is transiently suppressed during the preparation of movement. This preparatory inhibition is hypothesized to facilitate response selection and initiation. Given that demands on selection and initiation processes increase with movement complexity, we hypothesized that complexity would influence preparatory inhibition. To test this hypothesis, we probed corticospinal excitability during a delayed-response task in which participants were cued to prepare right- or left-hand movements of varying complexity. Single-pulse transcranial magnetic stimulation was applied over right primary motor cortex to elicit motor evoked potentials (MEPs) from the first dorsal interosseous (FDI) of the left hand. MEP suppression was greater during the preparation of responses involving coordination of the FDI and adductor digiti minimi relative to easier responses involving only the FDI, independent of which hand was cued to respond. In contrast, this increased inhibition was absent when the complex responses required sequential movements of the two muscles. Moreover, complexity did not influence the level of inhibition when the response hand was fixed for the trial block, regardless of whether the complex responses were performed simultaneously or sequentially. These results suggest that preparatory inhibition contributes to response selection, possibly by suppressing extraneous movements when responses involve the simultaneous coordination of multiple effectors.

Intracortical Inhibition During Volitional Inhibition of Prepared Action

2006 ◽  
Vol 95 (6) ◽  
pp. 3371-3383 ◽  
Author(s):  
James P. Coxon ◽  
Cathy M. Stinear ◽  
Winston D. Byblow
Keyword(s):  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Corticomotor Excitability ◽  
Hand Muscles ◽  
Cortical Level ◽  
A Site ◽  
Intrinsic Hand Muscles ◽  
Inhibitory Networks

Volitional inhibition is the voluntary prevention of a prepared movement. Here we ask whether primary motor cortex (M1) is a site of convergence of cortical activity associated with movement preparation and volitional inhibition. Volitional inhibition was studied by presenting a stop signal before execution of an anticipated response that requires a key lift to intercept a revolving dial. Motor evoked potentials (MEPs) were elicited in intrinsic hand muscles by transcranial magnetic stimulation (TMS) to assess corticomotor excitability and short interval intracortical inhibition (sICI) during task performance. The closer the stop cue was presented to the anticipated response, the harder it was for subjects to inhibit their response. Corticomotor pathway excitability was temporally modulated during volitional inhibition. Using subthreshold TMS, corticomotor excitability was reduced for Stop trials relative to Go trials from 140 ms after the cue. sICI was significantly greater for Stop trials compared with Go trials at a time that preceded the onset of muscle activity associated with the anticipated response. These results provide evidence that volitional inhibition is exerted at a cortical level and that inhibitory networks within M1 contribute to volitional inhibition of prepared action.

Corticomotor plasticity and learning of a ballistic thumb training task are diminished in older adults

2009 ◽  
Vol 107 (6) ◽  
pp. 1874-1883 ◽  
Author(s):  
Nigel C. Rogasch ◽  
Tamara J. Dartnall ◽  
John Cirillo ◽  
Michael A. Nordstrom ◽  
John G. Semmler
Keyword(s):  
Older Adults ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Training Task ◽  
Abductor Pollicis Brevis ◽  
Corticomotor Excitability ◽  
Old Adults ◽  
Young Subjects

This study examined changes in corticomotor excitability and plasticity after a thumb abduction training task in young and old adults. Electromyographic (EMG) recordings were obtained from right abductor pollicis brevis (APB, target muscle) and abductor digiti minimi (ADM, control muscle) in 14 young (18–24 yr) and 14 old (61–82 yr) adults. The training task consisted of 300 ballistic abductions of the right thumb to maximize peak thumb abduction acceleration (TAAcc). Transcranial magnetic stimulation (TMS) of the left primary motor cortex was used to assess changes in APB and ADM motor evoked potentials (MEPs) and short-interval intracortical inhibition (SICI) before, immediately after, and 30 min after training. No differences in corticomotor excitability (resting and active TMS thresholds, MEP input-output curves) or SICI were observed in young and old adults before training. Motor training resulted in improvements in peak TAAcc in young (177% improvement, P < 0.001) and old (124%, P = 0.005) subjects, with greater improvements in young subjects ( P = 0.002). Different thumb kinematics were observed during task performance, with increases in APB EMG related to improvements in peak TAAcc in young ( r2 = 0.46, P = 0.008) but not old ( r2 = 0.09, P = 0.3) adults. After training, APB MEPs were 50% larger ( P < 0.001 compared with before) in young subjects, with no change after training in old subjects ( P = 0.49), suggesting reduced use-dependent corticomotor plasticity with advancing age. These changes were specific to APB, because no training-related change in MEP amplitude was observed in ADM. No significant association was observed between change in APB MEP and improvement in TAAcc with training in individual young and old subjects. SICI remained unchanged after training in both groups, suggesting that it was not responsible for the diminished use-dependent corticomotor plasticity for this task in older adults.

scholarly journals Between-hand coupling during response inhibition

2019 ◽  
Vol 122 (4) ◽  
pp. 1357-1366 ◽  
Author(s):  
Corey G. Wadsley ◽  
John Cirillo ◽  
Winston D. Byblow
Keyword(s):  
Response Inhibition ◽  
Interference Effect ◽  
Primary Motor Cortex ◽  
Temporal Dynamics ◽  
Motor Evoked Potentials ◽  
Intracortical Inhibition ◽  
The Novel ◽  
Unitary Response ◽  
First Dorsal Interosseous Muscle ◽  
Response Task

Response inhibition reflects the process of terminating inappropriate preplanned or ongoing movements. When one hand is cued to stop after preparing a bimanual response (Partial trial), there is a substantial delay on the responding side. This delay is termed the interference effect and identifies a constraint that limits selective response inhibition. γ-Aminobutyric acid (GABA)-mediated networks within primary motor cortex (M1) may have distinct roles during response inhibition. In this study we examined whether the interference effect is the consequence of between-hand “coupling” into a unitary response and whether this is reflected in GABAergic intracortical inhibition within M1. Eighteen healthy right-handed participants performed a bimanual synchronous and asynchronous anticipatory response inhibition task. Electromyographic recordings were obtained from the first dorsal interosseous muscle bilaterally. Motor evoked potentials were elicited by single- and paired-pulse transcranial magnetic stimulation over right M1. As expected, Go trial performance was better with the synchronous compared with the asynchronous version of the task. Paradoxically, response delays during Partial trials were longer with the synchronous compared with the asynchronous task. Although task difficulty did not modulate GABAergic intracortical inhibition, there was a trend for between-hand coupling on asynchronous trials to be associated with greater GABAB receptor-mediated inhibition and lesser recruitment of GABAA receptor-mediated inhibition. The novel findings indicate that the interference effect is in part a consequence of between-hand coupling into a unitary response during movement preparation. The ability to respond independently with the two hands may rely on modulation of distinct inhibitory processes. NEW & NOTEWORTHY The temporal dynamics of an anticipated response task were manipulated to effect the difficulty of behavioral stopping and the underlying effects on motor neurophysiology. There were large response delays during trials where a subcomponent of an upcoming bimanual response was cued to stop in conditions where the anticipated action of the hands were synchronous, but not when asynchronous. Response delays reflected the integration of actions of both hands into a unitary response.

Suppression of Corticospinal Excitability During Negative Motor Imagery

2003 ◽  
Vol 90 (4) ◽  
pp. 2303-2309 ◽  
Author(s):  
Young H. Sohn ◽  
Nguyet Dang ◽  
Mark Hallett
Keyword(s):  
Motor Imagery ◽  
Motor Evoked Potentials ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Intracortical Facilitation ◽  
Abductor Pollicis Brevis ◽  
Paired Pulse ◽  
Left Hand ◽  
Resting Motor Threshold ◽  
Conditioning Stimuli

To investigate the effect of negative motor imagery on corticospinal excitability, we performed transcranial magnetic stimulation (TMS) studies in seven healthy subjects during imagination of suppressing movements. Subjects were asked to imagine suppression of TMS-induced twitching movement of their nondominant left hands by attempting to increase the amount of relaxation after receiving an auditory NoGo cue (negative motor imagery), but to imagine squeezing hands after a Go cue (positive motor imagery). Single- and paired-pulse TMS were triggered at 2 s after Go or NoGo cues. Motor-evoked potentials (MEPs) were recorded in the first dorsal interosseus (FDI), abductor pollicis brevis (APB), and abductor digiti minimi (ADM) muscles of the left hand. Paired-pulse TMS with subthreshold conditioning stimuli at interstimulus intervals of 2 (short intracortical inhibition) and 15 ms (intracortical facilitation) and that with suprathreshold conditioning stimuli at interstimulus interval of 80 ms (long intracortical inhibition) were performed in both negative motor imagery and control conditions. Compared with the control state (no imagination), MEP amplitudes of FDI (but not APB and ADM) were significantly suppressed in negative motor imagery, but those from all three muscles were unchanged during positive motor imagery. F-wave responses (amplitudes and persistence) were unchanged during both negative and positive motor imagery. During negative motor imagery, resting motor threshold was significantly increased, but short and long intracortical inhibition and intracortical facilitation were unchanged. The present results demonstrate that excitatory corticospinal drive is suppressed during imagination of suppressing movements.

Cutaneous anesthesia of the forearm enhances sensorimotor function of the hand

2013 ◽  
Vol 109 (4) ◽  
pp. 1091-1096 ◽  
Author(s):  
Matthew A. Petoe ◽  
Felipe A. Molina Jaque ◽  
Winston D. Byblow ◽  
Cathy M. Stinear
Keyword(s):  
Randomized Study ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Manual Dexterity ◽  
Cutaneous Sensation ◽  
Corticomotor Excitability ◽  
Left Hand ◽  
Spatial Acuity ◽  
Before And After ◽  
Neurophysiological Mechanisms

Temporary deafferentation of the upper limb, with ischemic or anesthetic nerve block, has rapid effects on sensorimotor cortex. Cutaneous anesthesia of the forearm has recently been found to improve sensory and motor function of the paretic hand in chronic stroke patients. However, the neurophysiological mechanisms are unknown. The aim of this study was to investigate the behavioral and neurophysiological effects of cutaneous forearm anesthesia. Twenty-five healthy right-handed adults participated in this double-blind, randomized study. Participants completed two sessions, with either a topical anesthesia cream (EMLA) or placebo applied to their left forearm in each session. Thresholds for cutaneous sensation and spatial acuity of the left hand were measured before and after the intervention. Transcranial magnetic stimulation was used to measure corticomotor excitability and short-interval intracortical inhibition in the left first dorsal interosseous and abductor digiti minimi muscles before and after the intervention. Manual dexterity was assessed with the grooved pegboard task after the intervention in each session. Left-hand dexterity improved to a greater extent after treatment with EMLA than placebo, and this was related to improved spatial acuity at the fingertips. Corticomotor excitability remained stable, and short-interval intracortical inhibition increased after EMLA treatment. We have confirmed and extended previous reports that cutaneous forearm anesthesia results in improved spatial acuity and manual dexterity of the ipsilateral hand. The neurophysiological mechanisms involve an increase in intracortical inhibition, which may improve the precision of voluntary movement. These results lend support to the therapeutic application of EMLA in movement rehabilitation.

scholarly journals Modulation of intracortical inhibition during physically performed and mentally simulated balance tasks

2021 ◽  
Vol 121 (5) ◽  
pp. 1379-1388
Author(s):  
A. Mouthon ◽  
J. Ruffieux ◽  
W. Taube
Keyword(s):  
Motor Evoked Potentials ◽  
Action Observation ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Mental Simulation ◽  
Task Execution ◽  
Postural Tasks ◽  
Execution Condition ◽  
The One ◽  
Postural Task

Abstract Purpose Action observation (AO) during motor imagery (MI), so-called AO + MI, has been proposed as a new form of non-physical training, but the neural mechanisms involved remains largely unknown. Therefore, this study aimed to explore whether there were similarities in the modulation of short-interval intracortical inhibition (SICI) during execution and mental simulation of postural tasks, and if there was a difference in modulation of SICI between AO + MI and AO alone. Method 21 young adults (mean ± SD = 24 ± 6.3 years) were asked to either passively observe (AO) or imagine while observing (AO + MI) or physically perform a stable and an unstable standing task, while motor evoked potentials and SICI were assessed in the soleus muscle. Result SICI results showed a modulation by condition (F2,40 = 6.42, p = 0.009) with less SICI in the execution condition compared to the AO + MI (p = 0.009) and AO (p = 0.002) condition. Moreover, switching from the stable to the unstable stance condition reduced significantly SICI (F1,20 = 8.34, p = 0.009) during both, physically performed (− 38.5%; p = 0.03) and mentally simulated balance (− 10%, p < 0.001, AO + MI and AO taken together). Conclusion The data demonstrate that SICI is reduced when switching from a stable to a more unstable standing task during both real task execution and mental simulation. Therefore, our results strengthen and further support the existence of similarities between executed and mentally simulated actions by showing that not only corticospinal excitability is similarly modulated but also SICI. This proposes that the activity of the inhibitory cortical network during mental simulation of balance tasks resembles the one during physical postural task execution.

Prefrontal Cortical Representation of Visuospatial Working Memory in Monkeys Examined by Local Inactivation With Muscimol

2001 ◽  
Vol 86 (4) ◽  
pp. 2041-2053 ◽  
Author(s):  
Toshiyuki Sawaguchi ◽  
Michiyo Iba
Keyword(s):  
Working Memory ◽  
Functional Organization ◽  
Visual Fields ◽  
Local Injection ◽  
Delayed Response ◽  
Visually Guided ◽  
Visuospatial Working Memory ◽  
Prefrontal Cortical ◽  
Response Task ◽  
Spatial Locations

In primates, dorsolateral areas of the prefrontal cortex (PFC) play a major role in visuospatial working memory. To examine the functional organization of the PFC for representing visuospatial working memory, we produced reversible local inactivation, with the local injection of muscimol (5 μg, 1 μl), at various sites ( n = 100) in the dorsolateral PFC of monkeys and observed the behavioral consequences in an oculomotor delayed-response task that required memory-guided saccades for locations throughout both visual fields. At 82 sites, the local injection of muscimol induced deficits in memory-guided saccades to a few specific, usually contralateral, target locations that varied with the location of the injection site. Such deficits depended on the delay length, and longer delays were associated with larger deficits in memory-guided saccades. The injection sites and affected spatial locations of the target showed a gross topographical relationship. No deficits appeared for a control task in which the subject was required to make a visually guided saccade to a visible target. These findings suggest that a specific site in the dorsolateral PFC is responsible for the working memory process for a specific visuospatial coordinate to guide goal-directed behavior. Further, memoranda for specific visuospatial coordinates appear to be represented in a topographical memory mapwithin the dorsolateral PFC to represent visuospatial working memory processes.

scholarly journals Modulation of corticomotor excitability in response to distal focal cooling

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6163 ◽  
Author(s):  
Yekta Ansari ◽  
Anthony Remaud ◽  
François Tremblay
Keyword(s):  
Skin Temperature ◽  
Motor Evoked Potentials ◽  
Secondary Analysis ◽  
Initial Study ◽  
Primary Analysis ◽  
Single Digit ◽  
Corticomotor Excitability ◽  
Individual Level ◽  
Cooling Phase ◽  
The Individual

Background Thermal stimulation has been proposed as a modality to facilitate motor recovery in neurological populations, such as stroke. Recently (Ansari, Remaud & Tremblay, 2018), we showed that application of cold or warm stimuli distally to a single digit produced a variable and short lasting modulation in corticomotor excitability. Here, our goal was to extend these observations to determine whether an increase in stimulation area could elicit more consistent modulation. Methods Participants (n = 22) consisted of a subset who participated in our initial study. Participants were asked to come for a second testing session where the thermal protocol was repeated but with extending the stimulation area from single-digit (SD) to multi-digits (MD, four fingers, no thumb). As in the first session, skin temperature and motor evoked potentials (MEPs) elicited with transcranial magnetic stimulation were measured at baseline (BL, neutral gel pack at 22 °C), at 1 min during the cooling application (pre-cooled 10 °C gel pack) and 5 and 10 min post-cooling (PC5 and PC10). The analysis combined the data obtained previously with single-SD cooling (Ansari, Remaud & Tremblay, 2018) with those obtained here for MD cooling. Results At BL, participants exhibited comparable measures of resting corticomotor excitability between testing sessions. MD cooling induced similar reductions in skin temperature as those recorded with SD cooling with a peak decline at C1 of respectively, −11.0 and −10.3 °C. For MEPs, the primary analysis revealed no main effect attributable to the stimulation area. A secondary analysis of individual responses to MD cooling revealed that half of the participants exhibited delayed MEP facilitation (11/22), while the other half showed delayed inhibition (10/22); which was sustained in the post-cooling phase. More importantly, a correlation between variations in MEP amplitude recorded during the SD cooling session with those recorded in the second session with MD cooling, revealed a very good degree of correspondence between the two at the individual level. Conclusion These results indicate that increasing the cooling area in the distal hand, while still eliciting variable responses, did produce more sustained modulation in MEP amplitude in the post-cooling phase. Our results also highlight that responses to cooling in terms of either depression or facilitation of corticomotor excitability tend to be fairly consistent in a given individual with repeated applications.

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