scholarly journals Different Modulation of the Cortical Silent Period by Two Phases of Short Interval Intracortical Inhibition

2007 ◽  
Vol 48 (5) ◽  
pp. 795 ◽  
Author(s):  
Suk Yun Kang ◽  
Hae-Won Shin ◽  
Young Ho Sohn
Keyword(s):  
Short Interval ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Cortical Silent Period ◽  
Two Phases

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 Fatigue-induced changes in short-interval intracortical inhibition and the silent period with stimulus intensities evoking maximal versus submaximal responses

2020 ◽  
Vol 129 (2) ◽  
pp. 205-217
Author(s):  
Callum G. Brownstein ◽  
Loïc Espeit ◽  
Nicolas Royer ◽  
Thomas Lapole ◽  
Guillaume Y. Millet
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Short Interval ◽  
Conditioning Stimulus ◽  
Silent Period ◽  
Single Pulse ◽  
Intracortical Inhibition ◽  
Fatiguing Exercise ◽  
Induced Changes

This study compared the change in silent period (SP) and short-interval intracortical inhibition (SICI) with conditioning stimulus and single-pulse transcranial magnetic stimulation (TMS) intensities (for SICI and SP, respectively) eliciting maximal and submaximal SICI and SP during fatiguing exercise. The results showed that changes in SICI were only detectable with intensities evoking maximal responses, with no difference between intensities for SP. These findings highlight the importance of maximizing SICI with appropriate intensities before measuring SICI during fatiguing exercise.

scholarly journals Determining the early corticospinal-motoneuronal responses to strength training: a systematic review and meta-analysis

2019 ◽  
Vol 30 (5) ◽  
pp. 463-476 ◽  
Author(s):  
Joel Mason ◽  
Ashlyn K. Frazer ◽  
Alan J. Pearce ◽  
Alicia M. Goodwill ◽  
Glyn Howatson ◽  
...  
Keyword(s):  
Systematic Review ◽  
Strength Training ◽  
Primary Motor Cortex ◽  
Meta Analysis ◽  
Short Interval ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Inhibitory Circuits ◽  
Intracortical Circuits ◽  
Meta Analyses

Abstract Several studies have used transcranial magnetic stimulation to probe the corticospinal-motoneuronal responses to a single session of strength training; however, the findings are inconsistent. This systematic review and meta-analysis examined whether a single bout of strength training affects the excitability and inhibition of intracortical circuits of the primary motor cortex (M1) and the corticospinal-motoneuronal pathway. A systematic review was completed, tracking studies between January 1990 and May 2018. The methodological quality of studies was determined using the Downs and Black quality index. Data were synthesised and interpreted from meta-analysis. Nine studies (n=107) investigating the acute corticospinal-motoneuronal responses to strength training met the inclusion criteria. Meta-analyses detected that after strength training compared to control, corticospinal excitability [standardised mean difference (SMD), 1.26; 95% confidence interval (CI), 0.88, 1.63; p<0.0001] and intracortical facilitation (ICF) (SMD, 1.60; 95% CI, 0.18, 3.02; p=0.003) were increased. The duration of the corticospinal silent period was reduced (SMD, −17.57; 95% CI, −21.12, −14.01; p=0.00001), but strength training had no effect on the excitability of the intracortical inhibitory circuits [short-interval intracortical inhibition (SICI) SMD, 1.01; 95% CI, −1.67, 3.69; p=0.46; long-interval intracortical inhibition (LICI) SMD, 0.50; 95% CI, −1.13, 2.13; p=0.55]. Strength training increased the excitability of corticospinal axons (SMD, 4.47; 95% CI, 3.45, 5.49; p<0.0001). This systematic review and meta-analyses revealed that the acute neural changes to strength training involve subtle changes along the entire neuroaxis from the M1 to the spinal cord. These findings suggest that strength training is a clinically useful tool to modulate intracortical circuits involved in motor control.

Late Cortical Disinhibition in Human Motor Cortex: A Triple-Pulse Transcranial Magnetic Stimulation Study

2010 ◽  
Vol 103 (1) ◽  
pp. 511-518 ◽  
Author(s):  
R. F. H. Cash ◽  
U. Ziemann ◽  
K. Murray ◽  
G. W. Thickbroom
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Short Interval ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Human Motor Cortex ◽  
Acid Type ◽  
Human Motor

In human motor cortex transcranial magnetic stimulation (TMS) has been used to identify short-interval intracortical inhibition (SICI) corresponding to γ-aminobutyric acid type A (GABAA) effects and long-interval intracortical inhibition (LICI) and the cortical silent period (SP) corresponding to postsynaptic GABAB effects. Presynaptic GABAB effects, corresponding to disinhibition, can also be identified with TMS and have been shown to be acting during LICI by measuring SICI after a suprathreshold priming stimulus (PS). The duration of disinhibition is not certain and, guided by studies in experimental preparations, we hypothesized that it may be longer-lasting than postsynaptic inhibition, leading to a period of late cortical disinhibition and consequently a net increase in corticospinal excitability. We tested this first by measuring the motor-evoked potential (MEP) to a test stimulus (TS), delivered after a PS at interpulse intervals (IPIs) ≤300 ms that encompassed the period of PS-induced LICI and its aftermath. MEP amplitude was initially decreased, but then increased at IPIs of 190–210 ms, reaching 160 ± 17% of baseline 200 ms after PS ( P < 0.05). SP duration was 181 ± 5 ms. A second experiment established that the onset of the later period of increased excitability correlated with PS intensity ( r2 = 0.99) and with the duration of the SP ( r2 = 0.99). The third and main experiment demonstrated that SICI was significantly reduced in strength at all IPIs ≤220 ms after PS. We conclude that TMS-induced LICI is associated with a period of disinhibition that is at first masked by LICI, but that outlasts LICI and gives rise to a period during which disinhibition predominates and net excitability is raised. Identification of this late period of disinhibition in human motor cortex may provide an opportunity to explore or modulate the behavior of excitatory networks at a time when inhibitory effects are restrained.

Impaired motor cortex inhibition in patients with amyotrophic lateral sclerosis

Neurology ◽  
1997 ◽  
Vol 49 (5) ◽  
pp. 1292-1298 ◽  
Author(s):  
Ulf Ziemann ◽  
Martin Winter ◽  
Carl D. Reimers ◽  
Karin Reimers ◽  
Frithjof Tergau ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Cortex ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Control Group ◽  
Cortical Silent Period ◽  
Healthy Control ◽  
Als Patients ◽  
Period Duration ◽  
Lateral Sclerosis

We investigated 14 patients with amyotrophic lateral sclerosis (ALS) by paired conditioning-test transcranial magnetic stimulation to test the hypothesis that the motor cortex is hyperexcitable in ALS. Intracortical(corticocortical) inhibition was significantly less in the ALS group than in an age-matched healthy control group (85.3 ± 27.0% versus 45.2± 15.5%, respectively; p < 0.0001). In contrast, intracortical facilitation, motor threshold, and cortical silent period duration in the ALS patients were not different from the control group. We suggest that the selective abnormality of intracortical inhibition is best compatible with an impaired function of inhibitory interneuronal circuits in the motor cortex that in turn renders the corticomotoneuron hyperexcitable.

scholarly journals Human Theta Burst Stimulation Combined with Subsequent Electroacupuncture Increases Corticospinal Excitability

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Jiali Li ◽  
Meng Ren ◽  
Wenjing Wang ◽  
Shutian Xu ◽  
Sicong Zhang ◽  
...  
Keyword(s):  
Motor Evoked Potentials ◽  
Short Interval ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Conduction Time ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Clinical Trial Registry ◽  
Theta Burst

Objective. Intermittent theta burst stimulation (iTBS) is a widely used noninvasive brain stimulation for the facilitation of corticospinal excitability (CSE). Previous studies have shown that acupuncture applied to acupoints associated with motor function in healthy people can reduce the amplitude of the motor-evoked potentials (MEPs), which reflects the inhibition of CSE. In our work, we wanted to test whether the combination of iTBS and electroacupuncture (EA) would have different effects on CSE in humans. Methods. A single-blind sham-controlled crossover design study was conducted on 20 healthy subjects. Subjects received 20 minutes’ sham or real EA stimulation immediately after sham or real iTBS. MEPs, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), cortical silent period (CSP), and central motor conduction time (CMCT) were recorded before each trial, and immediately, 20 minutes, and 40 minutes after the end of stimulation. Results. In the sham iTBS group, EA produced a reduction in MEPs amplitude, lasting approximately 40 minutes, while in the real iTBS group, EA significantly increased MEPs amplitude beyond 40 minutes after the end of stimulation. In sham EA group, the recorded MEPs amplitude showed no significant trend over time compared to baseline. Among all experiments, there were no significant changes in SICI, ICF, CSP, CMCT, etc. Conclusion. These data indicate that immediate application of EA after iTBS significantly increased corticospinal excitability. This trial was registered in the Chinese Clinical Trial Registry (registration no. ChiCTR1900025348).

Motor cortical disinhibition with baroreceptor unloading induced by orthostatic stress

2014 ◽  
Vol 111 (12) ◽  
pp. 2656-2664 ◽  
Author(s):  
Vasiliy E. Buharin ◽  
Andrew J. Butler ◽  
Minoru Shinohara
Keyword(s):  
Heart Rate ◽  
Lower Body Negative Pressure ◽  
Short Interval ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Frequency Component ◽  
Orthostatic Stress ◽  
Intracortical Facilitation ◽  
Arterial Blood ◽  
Intracortical Excitability

Unloading of the baroreceptors due to orthostatic stress increases corticospinal excitability. The purpose of this study was to examine the effects of baroreceptor unloading due to orthostatic stress on intracortical excitatory and inhibitory pathways in the motor cortex. With transcranial magnetic stimulation, measures of intracortical excitability for a hand muscle were tested on 2 days in healthy young adults. Lower body negative pressure (LBNP) of 40 mmHg was applied during one of the days and not during the Control day. During application of LBNP heart rate and the low-frequency component of heart rate variability increased, while mean arterial blood pressure was maintained. In the resting state, LBNP decreased short-interval intracortical inhibition (SICI) and had no effect on intracortical facilitation (ICF) or short-interval intracortical facilitation (SICF) compared with the Control day. During isometric contraction, no effects of LBNP were observed on tested measures of intracortical excitability including SICI, SICF, and cortical silent period. It was concluded that baroreceptor unloading due to orthostatic stress results in diminished intracortical inhibition, at least in the resting muscle.

scholarly journals Hyperexcitability and impaired intracortical inhibition in patients with fragile-X syndrome

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Florence Morin-Parent ◽  
Camille Champigny ◽  
Angelina Lacroix ◽  
François Corbin ◽  
Jean-François Lepage
Keyword(s):  
Fragile X Syndrome ◽  
Fragile X ◽  
Short Interval ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Primary Objective ◽  
Healthy Controls ◽  
Intracortical Facilitation ◽  
Cortical Hyperexcitability ◽  
Resting Motor Threshold

AbstractFragile-X syndrome (FXS) is characterized by neurological and psychiatric problems symptomatic of cortical hyperexcitability. Recent animal studies identified deficient γ-aminobutyricacid (GABA) inhibition as a key mechanism for hyperexcitability in FXS, but the GABA system remains largely unexplored in humans with the disorder. The primary objective of this study was to assess GABA-mediated inhibition and its relationship with hyperexcitability in patients with FXS. Transcranial magnetic stimulation (TMS) was used to assess cortical and corticospinal inhibitory and excitatory mechanisms in 18 patients with a molecular diagnosis of FXS and 18 healthy controls. GABA-mediated inhibition was measured with short-interval intracortical inhibition (GABAA), long-interval intracortical inhibition (GABAB), and the corticospinal silent period (GABAA+B). Net intracortical facilitation involving glutamate was assessed with intracortical facilitation, and corticospinal excitability was measured with the resting motor threshold. Results showed that FXS patients had significantly reduced short-interval intracortical inhibition, increased long-interval intracortical inhibition, and increased intracortical facilitation compared to healthy controls. In the FXS group, reduced short-interval intracortical inhibition was associated with heightened intracortical facilitation. Taken together, these results suggest that reduced GABAA inhibition is a plausible mechanism underlying cortical hyperexcitability in patients with FXS. These findings closely match those observed in animal models, supporting the translational validity of these markers for clinical research.

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