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https://hdl.handle.net/2440/118447
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Type: | Journal article |
Title: | Intermittent single-joint fatiguing exercise reduces TMS-EEG measures of cortical inhibition |
Author: | Otieno, L.A. Opie, G. Semmler, J. Ridding, M. Sidhu, S. |
Citation: | Journal of Neurophysiology, 2019; 121(2):471-479 |
Publisher: | American Physiological Society |
Issue Date: | 2019 |
ISSN: | 0022-3077 1522-1598 |
Statement of Responsibility: | Lavender A. Otieno, George M. Opie, John G. Semmler, Michael C. Ridding and Simranjit K. Sidhu |
Abstract: | Fatiguing intermittent single-joint exercise causes an increase in corticospinal excitability and a decrease in intracortical inhibition when measured with peripherally recorded motor evoked potentials (MEPs) after transcranial magnetic stimulation (TMS). Combined TMS and electroencephalography (TMS-EEG) allows for more direct recording of cortical responses through the TMS-evoked potential (TEP). The aim of this study was to investigate the changes in the excitatory and inhibitory components of the TEP during fatiguing single-joint exercise. Twenty-three young (22 ± 2 yr) healthy subjects performed intermittent 30-s maximum voluntary contractions of the right first dorsal interosseous muscle, followed by a 30-s relaxation period repeated for a total of 15 min. Six single-pulse TMSs and one peripheral nerve stimulation (PNS) to evoke maximal M wave (Mmax) were applied during each relaxation period. A total of 90 TMS pulses and 5 PNSs were applied before and after fatiguing exercise to record MEP and TEP. The amplitude of the MEP (normalized to Mmax) increased during fatiguing exercise ( P < 0.001). There were no changes in local and global P30, N45, and P180 of TEPs during the development of intermittent single-joint exercise-induced fatigue. Global analysis, however, revealed a decrease in N100 peak of the TEP during fatiguing exercise compared with before fatiguing exercise ( P = 0.02). The decrease in N100 suggests a fatigue-related decrease in global intracortical GABAB-mediated inhibition. The increase in corticospinal excitability typically observed during single-joint fatiguing exercise may be mediated by a global decrease in intracortical inhibition. NEW & NOTEWORTHY Fatiguing intermittent single-joint exercise causes an increase in corticospinal excitability and a decrease in intracortical inhibition when measured with transcranial magnetic stimulation (TMS)-evoked potentials from the muscle. The present study provides new and direct cortical evidence, using TMS-EEG to demonstrate that during single-joint fatiguing exercise there is a global decrease in intracortical GABAB-mediated inhibition. |
Keywords: | TMS-EEG cortical excitability cortical inhibition fatigue |
Rights: | © 2019 the American Physiological Society |
DOI: | 10.1152/jn.00628.2018 |
Grant ID: | http://purl.org/au-research/grants/nhmrc/1139723 |
Published version: | http://dx.doi.org/10.1152/jn.00628.2018 |
Appears in Collections: | Aurora harvest 8 Medicine publications |
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