Short interval intracortical inhibition and facilitation during the silent period in human

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.

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

Reviews in the Neurosciences ◽

10.1515/revneuro-2018-0054 ◽

2019 ◽

Vol 30 (5) ◽

pp. 463-476 ◽

Cited By ~ 11

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.

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

Journal of Neurophysiology ◽

10.1152/jn.00782.2009 ◽

2010 ◽

Vol 103 (1) ◽

pp. 511-518 ◽

Cited By ~ 60

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.

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Motor Cortex Excitability in Patients with Migraine with Aura and Hemiplegic Migraine

Cephalalgia ◽

10.1046/j.1468-2982.2000.00011.x ◽

2000 ◽

Vol 20 (1) ◽

pp. 45-50 ◽

Cited By ~ 55

Author(s):

KJ Werhahn ◽

K Wiseman ◽

J Herzog ◽

S Foörderreuther ◽

M Dichgans ◽

...

Keyword(s):

Motor Cortex ◽

Migraine With Aura ◽

Silent Period ◽

Intracortical Inhibition ◽

Familial Hemiplegic Migraine ◽

Hemiplegic Migraine ◽

Cortical Hyperexcitability ◽

Motor Cortex Excitability ◽

Patient Groups ◽

Intracortical Inhibition And Facilitation

We studied the excitability of the motor cortex using transcranial magnetic stimulation (TMS) in 12 patients with migraine with aura (MA) and nine patients with familial hemiplegic migraine (FHM). Motor thresholds at rest, the duration of the cortical and peripheral silent period and intracortical inhibition and facilitation using paired-pulse TMS at intervals of 2 to 15 ms were measured with patients free of attacks for at least 48 h. In contrast to previous reports we could not find any significant differences between patient groups and compared to controls ( n = 17) in the parameters tested. The results suggest that there are no interictal changes of excitability of the motor cortex in migraine. This study does not support the concept of general cortical hyperexcitability in migraine secondary to a genetic predisposition or a structural alteration of inhibitory interneurones in the cortex due to repeated parenchymal insults during attacks.

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

Yonsei Medical Journal ◽

10.3349/ymj.2007.48.5.795 ◽

2007 ◽

Vol 48 (5) ◽

pp. 795 ◽

Cited By ~ 6

Author(s):

Suk Yun Kang ◽

Hae-Won Shin ◽

Young Ho Sohn

Keyword(s):

Short Interval ◽

Silent Period ◽

Intracortical Inhibition ◽

Cortical Silent Period ◽

Two Phases

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Motor system inhibition in dopa-responsive dystonia and its modulation by treatment

Neurology ◽

10.1212/01.wnl.0000214304.03105.f4 ◽

2006 ◽

Vol 66 (7) ◽

pp. 1088-1090 ◽

Cited By ~ 20

Author(s):

Y. -Z. Huang ◽

I. Trender-Gerhard ◽

M. J. Edwards ◽

P. Mir ◽

J. C. Rothwell ◽

...

Keyword(s):

Motor System ◽

Silent Period ◽

Intracortical Inhibition ◽

Reciprocal Inhibition ◽

Blink Reflex ◽

Recovery Cycle ◽

Third Phase ◽

Intracortical Inhibition And Facilitation

Dopa-responsive dystonia (DRD) causes dystonia–parkinsonism, which is abolished by levodopa. The authors assessed short intracortical inhibition and facilitation, silent period, blink reflex recovery cycle, and reciprocal inhibition in seven patients with DRD on and off treatment. Short intracortical inhibition and blink reflex recovery cycle were reduced, but increased with treatment. Silent period was normal on and off treatment. Third phase of reciprocal inhibition was reduced on and off treatment. A discrete pattern of motor inhibitory dysfunction occurs in DRD.

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Human Theta Burst Stimulation Combined with Subsequent Electroacupuncture Increases Corticospinal Excitability

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/8824530 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8 ◽

Cited By ~ 1

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).

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Motor cortical disinhibition with baroreceptor unloading induced by orthostatic stress

Journal of Neurophysiology ◽

10.1152/jn.00778.2013 ◽

2014 ◽

Vol 111 (12) ◽

pp. 2656-2664 ◽

Cited By ~ 5

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.

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