scholarly journals Muscle Relaxation of the Foot Reduces Corticospinal Excitability of Hand Muscles and Enhances Intracortical Inhibition

2016 ◽  
Vol 10 ◽  
Author(s):  
Kouki Kato ◽  
Tetsuro Muraoka ◽  
Nobuaki Mizuguchi ◽  
Kento Nakagawa ◽  
Hiroki Nakata ◽  
...  
Keyword(s):  
Muscle Relaxation ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Hand Muscles

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.

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.

scholarly journals High-Volume Light-Load Strength Training, but Not Low-Volume Heavy-Load Strength Training Increases Corticospinal Excitability

2020 ◽  
Vol 2 (3) ◽  
pp. 1-12
Author(s):  
Rhys Painter ◽  
Simin Rahman ◽  
Woo Kim ◽  
Ummatul Siddique ◽  
Ashlyn Frazer ◽  
...  
Keyword(s):  
Strength Training ◽  
Short Interval ◽  
High Volume ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Control Group ◽  
Heavy Load ◽  
Post Exercise ◽  
Light Load ◽  
Low Volume

Purpose: To determine whether corticospinal excitability (CSE) and inhibition are differentially modulated following high-volume light-load strength training compared to low-volume heavy-load strength training. We hypothesised high-volume light-load strength training would increase CSE and low-volume heavy-load strength training would reduce intracortical inhibition. Methods: Transcranial magnetic stimulation (TMS) was used to assess CSE, short-interval intracortical inhibition (SICI), and silent period duration (SP) following high-volume light-load strength training (n = 9), low-volume heavy-load strength training (n = 8) compared to a control group (n = 10). Twenty-seven participants completed either (1) low-volume heavy-load strength training (80% one-repetition maximum [1RM]); (2) high-volume light-load strength training (20% 1-RM) or (3) a control condition. CSE, SICI and SP were measured using TMS at baseline and four time-points over a 60 min post-exercise period. Results: CSE increased rapidly (within 5 min post-exercise) for high-volume light-load strength training and remained elevated for 60 min compared to low-volume heavy-load strength training and control groups. There were no differences following any training for reduced SICI or SP. Conclusion: These results suggest that high-volume light-load strength training increases the excitability of corticospinal neurons and this increase is likely to be the predominant mechanism for increasing CSE for up to 60 min post training. It may be possible that a greater number of ST sessions are required to observe any differences in the excitability of the intrinsic inhibitory motor-network following high-volume light-load strength training and low-volume heavy-load strength training.

Corticospinal Excitability in the Hand Muscles is Decreased During Eye Movement with Visual Occlusion

2016 ◽  
Vol 122 (1) ◽  
pp. 238-255 ◽  
Author(s):  
Yuta Chujo ◽  
Yasutomo Jono ◽  
Keisuke Tani ◽  
Yoshifumi Nomura ◽  
Koichi Hiraoka
Keyword(s):  
Eye Movement ◽  
Corticospinal Excitability ◽  
Hand Muscles ◽  
Visual Occlusion

scholarly journals Physiological changes underlying bilateral isometric arm voluntary contractions in healthy humans

2011 ◽  
Vol 105 (4) ◽  
pp. 1594-1602 ◽  
Author(s):  
Demetris S. Soteropoulos ◽  
Monica A. Perez
Keyword(s):  
Tibialis Anterior ◽  
Motor Evoked Potentials ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Voluntary Contraction ◽  
Triceps Brachii ◽  
Hand Muscles ◽  
Healthy Humans ◽  
Simultaneous Activation ◽  
The Right

Many bilateral motor tasks engage simultaneous activation of distal and proximal arm muscles, but little is known about their physiological interactions. Here, we used transcranial magnetic stimulation to examine motor-evoked potentials (MEPs), interhemispheric inhibition at a conditioning-test interval of 10 (IHI10) and 40 ms (IHI40), and short-interval intracortical inhibition (SICI) in the left first dorsal interosseous (FDI) muscle during isometric index finger abduction. The right side remained at rest or performed isometric voluntary contraction with the FDI, biceps or triceps brachii, or the tibialis anterior. Left FDI MEPs were suppressed to a similar extent during contraction of the right FDI and biceps and triceps brachii but remained unchanged during contraction of the right tibialis anterior. IHI10 and IHI40 were decreased during contraction of the right biceps and triceps brachii compared with contraction of the right FDI. SICI was increased during activation of the right biceps and triceps brachii and decreased during activation of the right FDI. The present results indicate that an isometric voluntary contraction with either a distal or a proximal arm muscle, but not a foot dorsiflexor, decreases corticospinal output in a contralateral active finger muscle. Transcallosal inhibitory effects were strong during bilateral activation of distal hand muscles and weak during simultaneous activation of a distal and a proximal arm muscle, whereas GABAergic intracortical activity was modulated in the opposite manner. These findings suggest that in intact humans crossed interactions at the level of the motor cortex involved different physiological mechanisms when bilateral distal hand muscles are active and when a distal and a proximal arm muscle are simultaneously active.

Increasing corticospinal excitability in the antagonist muscle during muscle relaxation with a tracking task

2015 ◽  
Vol 32 (1) ◽  
pp. 39-43 ◽  
Author(s):  
Naoshin Yoshida ◽  
Tomofumi Yamaguchi ◽  
Kei Saitou ◽  
Shigeo Tanabe ◽  
Kenichi Sugawara
Keyword(s):  
Muscle Relaxation ◽  
Corticospinal Excitability ◽  
Tracking Task ◽  
Antagonist Muscle

Transfer of ballistic motor skill between bilateral and unilateral contexts in young and older adults: neural adaptations and behavioral implications

2013 ◽  
Vol 109 (12) ◽  
pp. 2963-2971 ◽  
Author(s):  
Mark R. Hinder ◽  
Timothy J. Carroll ◽  
Jeffery J. Summers
Keyword(s):  
Older Adults ◽  
Age Groups ◽  
Motor Task ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Neural Mechanisms ◽  
Ballistic Performance ◽  
Performance Improvements ◽  
Bimanual Movements ◽  
Bilateral Training

Bilateral movement rehabilitation is gaining popularity as an approach to improve the recovery not only of bimanual function but also of unilateral motor tasks. While the neural mechanisms mediating the transfer of bilateral training gains into unimanual contexts are not fully understood, converging evidence from behavioral, neurophysiological, and imaging studies suggests that bimanual movements are not simply the superposition of unimanual tasks undertaken with both (upper) limbs. Here we investigated the neural responses in both hemispheres to bilateral ballistic motor training and the extent to which performance improvements transferred to a unimanual task. Since aging influences interhemispheric interactions during movement production, both young ( n = 9; mean age 19.4 yr; 6 women, 3 men) and older ( n = 9; 66.3 yr; 7 women, 2 men) adults practiced a bilateral motor task requiring simultaneous “fast-as-possible” abductions of their left and right index fingers. Changes in bilateral and unilateral performance, and in corticospinal excitability and intracortical inhibition, were assessed. Strong transfer was observed between bimanual and unimanual contexts for both age groups. However, in contrast to previous reports of substantial bilateral cortical adaptations following unilateral training, increases in corticospinal excitability following bilateral training were not statistically reliable, and a release of intracortical inhibition was only observed for older adults. The results indicate that the neural mechanisms of motor learning for bilateral ballistic tasks differ from those that underlie unimanual ballistic performance improvement but that aging results in a greater overlap of the neural mechanisms mediating bilateral and unilateral ballistic motor performance.

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