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.

The cortical silent period

2012 ◽  
Author(s):  
Alexander Wolters ◽  
Ulf Ziemann ◽  
Reiner Benecke
Keyword(s):  
Silent Period ◽  
Cortical Inhibition ◽  
Gamma Aminobutyric Acid ◽  
Cortical Silent Period ◽  
Standardized Protocol ◽  
Pathological Conditions ◽  
Health And Disease ◽  
Voluntary Muscle Contraction ◽  
Contralateral Motor ◽  
Stimulation Of

The cortical silent period (cSP) refers to an interruption of voluntary muscle contraction by transcranial stimulation of the contralateral motor cortex. This article summarizes the physiology of cSP and gives guidelines as to how the cSP should be recorded and analysed, and refers to useful clinical applications. It describes the mechanisms at the spinal and supraspinal level can account for the cSP. It is currently thought that the cSP is mediated by gamma-aminobutyric acid receptors. cSP measurements are easy to obtain but require a standardized protocol to allow useful interpretation. Conditioning electrical stimulation of cutaneous nerves shortens the cSP. A conditioning transcranial magnetic stimulation pulse also affects cSP duration. The cSP duration is influenced by pathological conditions. cSP is an attractive probe to assess motor cortical inhibition in health and disease.

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.

Drug-induced changes in cortical inhibition in medication overuse headache

Cephalalgia ◽  
2011 ◽  
Vol 31 (12) ◽  
pp. 1282-1290 ◽  
Author(s):  
Antonio Currà ◽  
Gianluca Coppola ◽  
Manuela Gorini ◽  
Elisa Porretta ◽  
Martina Bracaglia ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Primary Motor Cortex ◽  
Medication Overuse ◽  
Medication Overuse Headache ◽  
Silent Period ◽  
Cortical Inhibition ◽  
Drug Induced ◽  
Normal Limits ◽  
Inhibitory Mechanisms ◽  
Episodic Migraineurs

Background: We investigated whether chronic headache related to medication overuse (MOH) is associated with changes in brain mechanisms regulating inhibitory cortical responses compared with healthy volunteers and episodic migraineurs recorded between attacks, and whether these changes differ according to the drug overused. Subjects and Methods: We studied 40 MOH patients whose symptoms were related to triptans alone, non-steroidal anti-inflammatory drugs (NSAIDs) or both medications combined, 12 migraineurs and 13 healthy volunteers. We used high-intensity transcranial magnetic stimulation over the primary motor cortex to assess the silent period from contracted perioral muscles. Results: In MOH patients the cortical silent period differed according to the type of headache medication overused: in patients overusing triptans alone it was shorter than in healthy volunteers (44.7 ± 14.2 vs. 108.1 ± 30.1 ms), but similar to that reported in migraineurs (59.9 ± 30.4 ms), whereas in patients overusing NSAIDs alone or triptans and NSAIDs combined duration of silent period was within normal limits (80.6 ± 46.4 and 103.8 ± 47.2 ms). Conclusions: Compared with episodic migraineurs, MOH patients overusing triptans have no significant change in cortical inhibition, whereas those overusing NSAIDs have an increase in cortical inhibitory mechanisms. We attribute these changes to medication-induced neural adaptation promoted by changes in central serotonin neurotransmission.

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 Ultrasound stimulation of the motor cortex during tonic muscle contraction

2021 ◽  
Author(s):  
Ian Szwast Heimbuch ◽  
Tiffany Fan ◽  
Allan Wu ◽  
Guido C Faas ◽  
Andrew C Charles ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Muscle Contraction ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Silent Period ◽  
Transcranial Ultrasound ◽  
Emg Activity ◽  
Ultrasound Stimulation ◽  
Tonic Muscle

Transcranial ultrasound stimulation (tUS) shows potential as a noninvasive brain stimulation (NIBS) technique, offering increased spatial precision compared to other NIBS techniques. However, its reported effects on primary motor cortex (M1) are limited. We aimed to better understand tUS effects in human M1 by performing tUS of the hand area of M1 (M1hand) during tonic muscle contraction of the index finger. Stimulation during muscle contraction was chosen because of the transcranial magnetic stimulation-induced phenomenon known as cortical silent period (cSP), in which transcranial magnetic stimulation (TMS) of M1hand involuntarily suppresses voluntary motor activity. Since cSP is widely considered an inhibitory phenomenon, it presents an ideal parallel for tUS, which has often been proposed to preferentially influence inhibitory interneurons. Recording electromyography (EMG) of the first dorsal interosseous (FDI) muscle, we investigated effects on muscle activity both during and after tUS. We found no change in FDI EMG activity concurrent with tUS stimulation. Using single-pulse TMS, we found no difference in M1 excitability before versus after sparsely repetitive tUS exposure. Using acoustic simulations in models made from structural MRI of the participants that matched the experimental setups, we estimated in-brain pressures and generated an estimate of cumulative tUS exposure experienced by M1hand for each subject. We were unable to find any correlation between cumulative M1hand exposure and M1 excitability change. We also present data that suggest a TMS-induced MEP always preceded a near-threshold cSP.

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 Sphingolipid lysosomal storage diseases: from bench to bedside

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Muna Abed Rabbo ◽  
Yara Khodour ◽  
Laurie S. Kaguni ◽  
Johnny Stiban
Keyword(s):  
Basic Research ◽  
Lysosomal Storage Diseases ◽  
Therapeutic Strategies ◽  
Clinical Applications ◽  
Late Nineteenth Century ◽  
Lysosomal Storage ◽  
Storage Diseases ◽  
The Past ◽  
Health And Disease ◽  
General Aspects

AbstractJohann Ludwig Wilhelm Thudicum described sphingolipids (SLs) in the late nineteenth century, but it was only in the past fifty years that SL research surged in importance and applicability. Currently, sphingolipids and their metabolism are hotly debated topics in various biochemical fields. Similar to other macromolecular reactions, SL metabolism has important implications in health and disease in most cells. A plethora of SL-related genetic ailments has been described. Defects in SL catabolism can cause the accumulation of SLs, leading to many types of lysosomal storage diseases (LSDs) collectively called sphingolipidoses. These diseases mainly impact the neuronal and immune systems, but other systems can be affected as well. This review aims to present a comprehensive, up-to-date picture of the rapidly growing field of sphingolipid LSDs, their etiology, pathology, and potential therapeutic strategies. We first describe LSDs biochemically and briefly discuss their catabolism, followed by general aspects of the major diseases such as Gaucher, Krabbe, Fabry, and Farber among others. We conclude with an overview of the available and potential future therapies for many of the diseases. We strive to present the most important and recent findings from basic research and clinical applications, and to provide a valuable source for understanding these disorders.

scholarly journals The exosome journey: from biogenesis to uptake and intracellular signalling

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Sonam Gurung ◽  
Dany Perocheau ◽  
Loukia Touramanidou ◽  
Julien Baruteau
Keyword(s):  
Clinical Trials ◽  
Plasma Membrane ◽  
Scientific Community ◽  
Cell Types ◽  
Clinical Applications ◽  
Clinical Development ◽  
Intracellular Signalling ◽  
Clinical Settings ◽  
Health And Disease ◽  
Adequate Definition

AbstractThe use of exosomes in clinical settings is progressively becoming a reality, as clinical trials testing exosomes for diagnostic and therapeutic applications are generating remarkable interest from the scientific community and investors. Exosomes are small extracellular vesicles secreted by all cell types playing intercellular communication roles in health and disease by transferring cellular cargoes such as functional proteins, metabolites and nucleic acids to recipient cells. An in-depth understanding of exosome biology is therefore essential to ensure clinical development of exosome based investigational therapeutic products. Here we summarise the most up-to-date knowkedge about the complex biological journey of exosomes from biogenesis and secretion, transport and uptake to their intracellular signalling. We delineate the major pathways and molecular players that influence each step of exosome physiology, highlighting the routes of interest, which will be of benefit to exosome manipulation and engineering. We highlight the main controversies in the field of exosome research: their adequate definition, characterisation and biogenesis at plasma membrane. We also delineate the most common identified pitfalls affecting exosome research and development. Unravelling exosome physiology is key to their ultimate progression towards clinical applications.

Shortened cortical silent period in facial muscles of patients with migraine

Pain ◽  
2007 ◽  
Vol 132 (1) ◽  
pp. 124-131 ◽  
Author(s):  
Antonio Curra ◽  
Francesco Pierelli ◽  
Gianluca Coppola ◽  
Piero Barbanti ◽  
Maria Gabriella Buzzi ◽  
...  
Keyword(s):  
Silent Period ◽  
Cortical Silent Period ◽  
Facial Muscles
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