scholarly journals Anatomo-Functional Origins of the Cortical Silent Period: Spotlight on the Basal Ganglia

2021 ◽  
Vol 11 (6) ◽  
pp. 705
Author(s):  
David Zeugin ◽  
Silvio Ionta
Keyword(s):  
Basal Ganglia ◽  
Primary Motor Cortex ◽  
Technological Development ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Cortical Silent Period ◽  
Relevant Evidence ◽  
Attentional Load ◽  
Fundamental Research ◽  
Future Work

The so-called cortical silent period (CSP) refers to the temporary interruption of electromyographic signal from a muscle following a motor-evoked potential (MEP) triggered by transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). The neurophysiological origins of the CSP are debated. Previous evidence suggests that both spinal and cortical mechanisms may account for the duration of the CSP. However, contextual factors such as cortical fatigue, experimental procedures, attentional load, as well as neuropathology can also influence the CSP duration. The present paper summarizes the most relevant evidence on the mechanisms underlying the duration of the CSP, with a particular focus on the central role of the basal ganglia in the “direct” (excitatory), “indirect” (inhibitory), and “hyperdirect” cortico-subcortical pathways to manage cortical motor inhibition. We propose new methods of interpretation of the CSP related, at least partially, to the inhibitory hyperdirect and indirect pathways in the basal ganglia. This view may help to explain the respective shortening and lengthening of the CSP in various neurological disorders. Shedding light on the complexity of the CSP’s origins, the present review aims at constituting a reference for future work in fundamental research, technological development, and clinical settings.

scholarly journals Cortical silent period reflects individual differences in action stopping performance

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mario Paci ◽  
Giulio Di Cosmo ◽  
Mauro Gianni Perrucci ◽  
Francesca Ferri ◽  
Marcello Costantini
Keyword(s):  
Individual Differences ◽  
Response Inhibition ◽  
Primary Motor Cortex ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Stop Signal ◽  
Stop Signal Task ◽  
Behavioral Differences ◽  
Cortical Silent Period ◽  
Stop Signal Reaction Time

AbstractInhibitory control is the ability to suppress inappropriate movements and unwanted actions, allowing to regulate impulses and responses. This ability can be measured via the Stop Signal Task, which provides a temporal index of response inhibition, namely the stop signal reaction time (SSRT). At the neural level, Transcranial Magnetic Stimulation (TMS) allows to investigate motor inhibition within the primary motor cortex (M1), such as the cortical silent period (CSP) which is an index of GABAB-mediated intracortical inhibition within M1. Although there is strong evidence that intracortical inhibition varies during action stopping, it is still not clear whether differences in the neurophysiological markers of intracortical inhibition contribute to behavioral differences in actual inhibitory capacities. Hence, here we explored the relationship between intracortical inhibition within M1 and behavioral response inhibition. GABABergic-mediated inhibition in M1 was determined by the duration of CSP, while behavioral inhibition was assessed by the SSRT. We found a significant positive correlation between CSP’s duration and SSRT, namely that individuals with greater levels of GABABergic-mediated inhibition seem to perform overall worse in inhibiting behavioral responses. These results support the assumption that individual differences in intracortical inhibition are mirrored by individual differences in action stopping abilities.

scholarly journals Mechanisms and Dynamics of Cortical Motor Inhibition in the Stop-signal Paradigm: A TMS Study

2010 ◽  
Vol 22 (2) ◽  
pp. 225-239 ◽  
Author(s):  
Wery P. M. van den Wildenberg ◽  
Borís Burle ◽  
Franck Vidal ◽  
Maurits W. van der Molen ◽  
K. Richard Ridderinkhof ◽  
...  
Keyword(s):  
Time Course ◽  
Primary Motor Cortex ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Single Pulse ◽  
Stop Signal ◽  
Neural Basis ◽  
Manual Response ◽  
Inhibitory Circuits ◽  
Voluntary Behavior

The ability to stop ongoing motor responses in a split-second is a vital element of human cognitive control and flexibility that relies in large part on prefrontal cortex. We used the stop-signal paradigm to elucidate the engagement of primary motor cortex (M1) in inhibiting an ongoing voluntary motor response. The stop-signal paradigm taps the ability to flexibly countermand ongoing voluntary behavior upon presentation of a stop signal. We applied single-pulse TMS to M1 at several intervals following the stop signal to track the time course of excitability of the motor system related to generating and stopping a manual response. Electromyography recorded from the flexor pollicis brevis allowed quantification of the excitability of the corticospinal tract and the involvement of intracortical GABABergic circuits within M1, indexed respectively by the amplitude of the motor-evoked potential and the duration of the late part of the cortical silent period (SP). The results extend our knowledge of the neural basis of inhibitory control in three ways. First, the results revealed a dynamic interplay between response activation and stopping processes at M1 level during stop-signal inhibition of an ongoing response. Second, increased excitability of inhibitory interneurons that drives SP prolongation was evident as early as 134 msec following the instruction to stop. Third, this pattern was followed by a stop-related reduction of corticospinal excitability implemented around 180 after the stop signal. These findings point to the recruitment of GABABergic intracortical inhibitory circuits within M1 in stop-signal inhibition and support the notion of stopping as an active act of control.

The effect of acetaminophen ingestion on cortico-spinal excitability

2013 ◽  
Vol 91 (2) ◽  
pp. 187-189 ◽  
Author(s):  
Alexis R. Mauger ◽  
James G. Hopker
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Sodium Currents ◽  
Cortical Silent Period ◽  
Voltage Gated ◽  
Spinal Excitability

Acetaminophen (ACT) facilitates the inhibition of voltage-gated calcium and sodium currents, which may effect cortico-spinal excitability. Twelve subjects ingested acetaminophen or a placebo and underwent transcranial magnetic stimulation to assess the motor evoked potential (MEP), and cortical silent period (CSP). ACT significantly increased MEP response (P > 0.05) but had no effect on CSP (P > 0.05). This indicates that ACT increases MEP and should be controlled for in studies where these measures are of interest.

Cortical silent period

2021 ◽  
Author(s):  
Markus Kofler ◽  
Ulf Ziemann ◽  
Vasilios K. Kimiskidis
Keyword(s):  
Primary Motor Cortex ◽  
Silent Period ◽  
Clinical Applications ◽  
Emg Activity ◽  
Cortical Silent Period ◽  
Physiological Basis ◽  
Inhibitory Mechanisms ◽  
Magnetic Stimulus ◽  
Health And Disease ◽  
Voluntary Muscle Contraction

The cortical silent period (cSP) refers to a period of suppression or silencing of ongoing electromyographic (EMG) activity during voluntary muscle contraction induced by a magnetic stimulus over the contralateral primary motor cortex. This chapter summarizes the physiological basis of the cSP, discusses technical aspects and recommendations on how to record and analyze it, and provides an overview of useful clinical applications. Evidence is presented that multiple spinal mechanisms are implicated in the initial part of the cSP, but some may be also active further on, whereas long-lasting cortical inhibitory mechanisms operate throughout the entire cSP, with an emphasis during its later part. The cSP is a highly relevant and clinically useful tool to assess inhibitory corticomotoneuronal mechanisms in health and disease.

scholarly journals Cerebellar Transcranial Magnetic Stimulation Reduces the Silent Period on Hand Muscle Electromyography During Force Control

2020 ◽  
Vol 10 (2) ◽  
pp. 63 ◽  
Author(s):  
Akiyoshi Matsugi ◽  
Shinya Douchi ◽  
Kodai Suzuki ◽  
Kosuke Oku ◽  
Nobuhiko Mori ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Maximum Voluntary Contraction ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Voluntary Contraction ◽  
Resting Motor Threshold ◽  
First Dorsal Interosseous Muscle ◽  
The Right

This study aimed to investigate whether cerebellar transcranial magnetic stimulation (C-TMS) affected the cortical silent period (cSP) induced by TMS over the primary motor cortex (M1) and the effect of interstimulus interval (ISI) on cerebellar conditioning and TMS to the left M1 (M1-TMS). Fourteen healthy adult participants were instructed to control the abduction force of the right index finger to 20% of the maximum voluntary contraction. M1-TMS was delivered during this to induce cSP on electromyograph of the right first dorsal interosseous muscle. TMS over the right cerebellum (C-TMS) was conducted prior to M1-TMS. In the first experiment, M1-TMS intensity was set to 1 or 1.3 × resting motor threshold (rMT) with 20-ms ISI. In the second experiment, the intensity was set to 1 × rMT with ISI of 0, 10, 20, 30, 40, 50, 60, 70, or 80 ms, and no-C-TMS trials were inserted. In results, cSP was significantly shorter in 1 × rMT condition than in 1.3 × rMT by C-TMS, and cSP was significantly shorter for ISI of 20–40 ms than for the no-C-TMS condition. Further, motor evoked potential for ISI40-60 ms were significantly reduced than that for ISI0. Thus, C-TMS may reduce cSP induced by M1-TMS with ISI of 20–40 ms.

Motor-Evoked Potentials of the Abductor Hallucis Muscle and Their Relationship with Foot Arch Functional Anatomy

2017 ◽  
Vol 107 (5) ◽  
pp. 467-470
Author(s):  
Tyrone Mayorga ◽  
Erato Giokas ◽  
Anaida Abagyan ◽  
Dhaval Patel ◽  
Yasmin Sarraf ◽  
...  
Keyword(s):  
Motor Evoked Potential ◽  
Silent Period ◽  
Functional Neuroanatomy ◽  
Motor Threshold ◽  
Abductor Hallucis ◽  
Cortical Silent Period ◽  
Foot Length ◽  
Resting Motor Threshold ◽  
Foot Arch ◽  
Period Duration

Background: The present study aimed to investigate the correlation between abductor hallucis (AH) muscle motor evoked potential (MEP) amplitude and foot arch anatomy. Methods: Twelve healthy individuals underwent foot arch measurement using a digital photographic technique and measurements of cortical excitability using transcranial magnetic stimulation applied on the cortical representation area of the right AH muscle. Truncated foot length and dorsal height were then measured and used to create the arch height index (AHI). Resting motor threshold, MEP amplitude (using a stimulation intensity of 110% resting motor threshold), and cortical silent period duration were also measured. Results: Mean ± SE values were as follows: truncated foot length, 16.72 ± 0.3 cm; dorsal height, 5.62 ± 0.13 cm; AHI, 0.34 ± 0.01; resting motor threshold, 81.6% ± 2.12%; MEP amplitude, 0.71 ± 0.1 mV; and cortical silent period duration, 108.05 ± 0.45 msec. A significant correlation was found between MEP amplitude and AHI (Spearman's rho: P < .01). Conclusions: These results indicate that AH muscle functional neuroanatomy measurements are reliable and might be used by clinicians and therapists to investigate foot arch physiology and monitor the efficacy of treatments and rehabilitative protocols.

scholarly journals Supraspinal fatigue impedes recovery from a low-intensity sustained contraction in old adults

2012 ◽  
Vol 112 (5) ◽  
pp. 849-858 ◽  
Author(s):  
Tejin Yoon ◽  
Bonnie Schlinder-Delap ◽  
Manda L. Keller ◽  
Sandra K. Hunter
Keyword(s):  
Young Adults ◽  
Pressor Response ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Voluntary Activation ◽  
Age Difference ◽  
Task Failure ◽  
Old Adults ◽  
Sustained Contraction ◽  
Low Intensity

This study determined the contribution of supraspinal fatigue and contractile properties to the age difference in neuromuscular fatigue during and recovery from a low-intensity sustained contraction. Cortical stimulation was used to evoke measures of voluntary activation and muscle relaxation during and after a contraction sustained at 20% of maximal voluntary contraction (MVC) until task failure with elbow flexor muscles in 14 young adults (20.9 ± 3.6 yr, 7 men) and 14 old adults (71.6 ± 5.4 yr, 7 men). Old adults exhibited a longer time to task failure than the young adults (23.8 ± 9.0 vs. 11.5 ± 3.9 min, respectively, P < 0.001). The time to failure was associated with initial peak rates of relaxation of muscle fibers and pressor response ( P < 0.05). Increments in torque (superimposed twitch; SIT) generated by transcranial magnetic stimulation (TMS) during brief MVCs, increased during the fatiguing contraction ( P < 0.001) and then decreased during recovery ( P = 0.02). The increase in the SIT was greater for the old adults than the young adults during the fatiguing contraction and recovery ( P < 0.05). Recovery of MVC torque was less for old than young adults at 10 min post-fatiguing contraction (75.1 ± 8.7 vs. 83.6 ± 7.8% of control MVC, respectively, P = 0.01) and was associated with the recovery of the SIT ( r = −0.59, r2 = 0.35, P < 0.001). Motor evoked potential (MEP) amplitude and the silent period elicited during the fatiguing contraction increased less for old adults than young adults ( P < 0.05). The greater fatigue resistance with age during a low-intensity sustained contraction was attributable to mechanisms located within the muscle. Recovery of maximal strength after the low-intensity fatiguing contraction however, was impeded more for old adults than young because of greater supraspinal fatigue. Recovery of strength could be an important variable to consider in exercise prescription of old populations.

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