Threshold Tracked Short-Interval Intracortical Inhibition More Closely Predicts the Cortical Response to Transcranial Magnetic Stimulation

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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Short Interval Intracortical Inhibition Responses to Low-Frequency Repetitive Transcranial Magnetic Stimulation Under Multiple Interstimulus Intervals and Conditioning Intensities

Neuromodulation Technology at the Neural Interface ◽

10.1111/ner.12773 ◽

2018 ◽

Vol 21 (4) ◽

pp. 368-375

Author(s):

Mo Chen ◽

Maíra C. Lixandrão ◽

Cecília N. Prudente ◽

Rebekah L. S. Summers ◽

Teresa J. Kimberley

Keyword(s):

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Repetitive Transcranial Magnetic Stimulation ◽

Short Interval ◽

Low Frequency ◽

Intracortical Inhibition ◽

Interstimulus Intervals

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Consensus paper on short-interval intracortical inhibition and other transcranial magnetic stimulation intracortical paradigms in movement disorders

Brain Stimulation ◽

10.1016/j.brs.2008.06.005 ◽

2008 ◽

Vol 1 (3) ◽

pp. 183-191 ◽

Cited By ~ 73

Author(s):

Alfredo Berardelli ◽

Giovanni Abbruzzese ◽

Robert Chen ◽

Michael Orth ◽

Michael C. Ridding ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Movement Disorders ◽

Magnetic Stimulation ◽

Short Interval ◽

Intracortical Inhibition ◽

Consensus Paper

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Short-interval intracortical inhibition in human primary motor cortex: A multi-locus transcranial magnetic stimulation study

NeuroImage ◽

10.1016/j.neuroimage.2019.116194 ◽

2019 ◽

Vol 203 ◽

pp. 116194 ◽

Cited By ~ 2

Author(s):

Jaakko O. Nieminen ◽

Lari M. Koponen ◽

Niko Mäkelä ◽

Victor Hugo Souza ◽

Matti Stenroos ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Motor Cortex ◽

Magnetic Stimulation ◽

Primary Motor Cortex ◽

Short Interval ◽

Intracortical Inhibition

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The effect of experimental pain on short-interval intracortical inhibition with multi-locus transcranial magnetic stimulation

Experimental Brain Research ◽

10.1007/s00221-019-05502-5 ◽

2019 ◽

Vol 237 (6) ◽

pp. 1503-1510 ◽

Cited By ~ 5

Author(s):

Karita S.-T. Salo ◽

Selja M. I. Vaalto ◽

Lari M. Koponen ◽

Jaakko O. Nieminen ◽

Risto J. Ilmoniemi

Keyword(s):

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Short Interval ◽

Experimental Pain ◽

Intracortical Inhibition

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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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Transcranial Magnetic Stimulation Markers of Antidepressant Treatment in Adolescents With Major Depressive Disorder

The International Journal of Neuropsychopharmacology ◽

10.1093/ijnp/pyz021 ◽

2019 ◽

Vol 22 (7) ◽

pp. 435-444 ◽

Cited By ~ 2

Author(s):

Deniz Doruk Camsari ◽

Charles P Lewis ◽

Ayse Irem Sonmez ◽

Aiswarya Laks Nandakumar ◽

Marjorie A Gresbrink ◽

...

Keyword(s):

Major Depressive Disorder ◽

Transcranial Magnetic Stimulation ◽

Depressive Disorder ◽

Magnetic Stimulation ◽

Antidepressant Treatment ◽

Short Interval ◽

Intracortical Inhibition ◽

Cortical Inhibition ◽

Major Depressive ◽

Children’S Depression

Abstract Background The goal of this study was to examine baseline transcranial magnetic stimulation measures of cortical inhibition and excitability in depressed patients and characterize their longitudinal posttreatment changes. Methods Fifteen adolescents (age 13–17 years) with moderate to severe major depressive disorder and 22 healthy controls (age 9–17) underwent single- and paired-pulse transcranial magnetic stimulation and clinical assessments. Transcranial magnetic stimulation measures included short-interval intracortical inhibition (2 and 4 milliseconds), long-interval intracortical inhibition (100, 150, and 200 milliseconds), cortical silent period, and intracortical facilitation (10, 15, and 20 milliseconds). Ten participants with major depressive disorder initiated antidepressant treatment or had dose adjustments. These participants were reassessed after treatment. Depression symptom severity was measured with the Children’s Depression Rating Scale, Revised. Robust regression modeling compared healthy and depressed adolescents at baseline. Relationships between changes in cortical inhibition and changes in depressive symptom severity were assessed in the depressed adolescents receiving antidepressant treatment. Results Our results revealed that at baseline, short-interval intracortical inhibition-2 was significantly reduced (Padj = .01) in depressed participants, suggesting impaired cortical inhibition compared with healthy controls. At follow-up, improvement in Children’s Depression Rating Scale, Revised scores correlated with improvement in short-interval intracortical inhibition-4 amplitude (greater inhibition) after antidepressant treatment (R2 = 0.63; P = .01). Conclusions These results suggest that cortical inhibition measures may have promise as biomarkers in adolescents treated for depression.

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Unravelling the modulation of intracortical inhibition during motor imagery: An adaptive threshold-hunting study

10.1101/846931 ◽

2019 ◽

Author(s):

Cécilia Neige ◽

Dylan Rannaud Monany ◽

Cathy M. Stinear ◽

Winston D. Byblow ◽

Charalambos Papaxanthis ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Motor Cortex ◽

Motor Imagery ◽

Magnetic Stimulation ◽

Primary Motor Cortex ◽

Short Interval ◽

Intracortical Inhibition ◽

Adaptive Threshold ◽

Mental Simulation ◽

The Right

AbstractMotor imagery (MI) is the mental simulation of an action without any apparent muscular contraction. By means of transcranial magnetic stimulation, few studies revealed a decrease of short-interval intracortical inhibition (SICI) within the primary motor cortex. However, this decrease is ambiguous, as one would expect greater inhibition during MI to prevent overt motor output. The current study investigated the extent of SICI modulation during MI through a methodological and a conceptual reconsideration of i) the importance of parameters to assess SICI (Exp.1) and ii) the inhibitory process within the primary motor cortex as an inherent feature of MI (Exp.2). Participants performed two tasks: 1) rest and 2) imagery of isometric abduction of the right index finger. Using transcranial magnetic stimulation, motor evoked potentials were elicited in the right first dorsal interosseous muscle. An adaptive threshold-hunting paradigm was used, where the stimulus intensity required to maintain a fixed motor evoked potential amplitude was quantified. To test SICI, we conditioned the test stimulus with a conditioning stimulus (CS) of different intensities. Results revealed an Intensity by Task interaction showing that SICI decreased during MI as compared to rest only for the higher CS intensity (Exp.1). At the lowest CS intensities, a Task main effect revealed that SICI increased during MI (Exp.2). SICI modulation during MI depends critically on the CS intensity. By optimising CS intensity, we have shown that SICI circuits may increase during MI, revealing a potential mechanism to prevent the production of a movement while the motor system is activated.HighlightsExcitatory and inhibitory neural processes interact during motor imagery, as the motor regions are activated but no movement is produced.The current study investigated the extent of short interval intracortical inhibition modulation (SICI) during motor imagery.When using optimal settings, SICI increased during motor imagery, likely to prevent the production of an overt movement.

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Freely chosen cadence during cycling attenuates intracortical inhibition and increases intracortical facilitation compared to a similar fixed cadence

10.1101/2020.04.23.056820 ◽

2020 ◽

Author(s):

Simranjit Sidhu ◽

Benedikt Lauber

Keyword(s):

Energy Consumption ◽

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Short Interval ◽

Intracortical Inhibition ◽

Movement Rate ◽

Intracortical Facilitation ◽

Neurophysiological Mechanisms

AbstractIn contrast to other rhythmic tasks such as running, the preferred movement rate in cycling does not minimize energy consumption. It is possible that neurophysiological mechanisms contribute to the choice of cadence, however this phenomenon is not well understood. Eleven participants cycled at a fixed workload of 125 W and different cadences including a freely chosen cadence (FCC, ∼72), and fixed cadences of 70, 80, 90 and 100 revolutions per minute (rpm) during which transcranial magnetic stimulation (TMS) was used to measure short interval intracortical inhibition (SICI) and intracortical facilitation (ICF). There was significant increase in SICI at 70 (P = 0.004), 80 (P = 0.008) and 100 rpm (P = 0.041) compared to FCC. ICF was significantly reduced at 70 rpm compared to FCC (P = 0.04). Inhibition-excitation ratio (SICI divided by ICF) declined (P = 0.014) with an increase in cadence. The results demonstrate that SICI is attenuated during FCC compared to fixed cadences. The outcomes suggest that the attenuation of intracortical inhibition and augmentation of ICF may be a contributing factor for FCC.

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