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Intermittent single-joint fatiguing exercise reduces TMS-EEG measures of cortical inhibition.
J Neurophysiol 2019; 121(2):471-479JN

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.

Authors+Show Affiliations

Discipline of Physiology, Adelaide Medical School, The University of Adelaide , Adelaide, South Australia , Australia.Discipline of Physiology, Adelaide Medical School, The University of Adelaide , Adelaide, South Australia , Australia. Robinson Research Institute, Adelaide Medical School, The University of Adelaide , Adelaide, South Australia , Australia.Discipline of Physiology, Adelaide Medical School, The University of Adelaide , Adelaide, South Australia , Australia.Robinson Research Institute, Adelaide Medical School, The University of Adelaide , Adelaide, South Australia , Australia.Discipline of Physiology, Adelaide Medical School, The University of Adelaide , Adelaide, South Australia , Australia.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30565971

Citation

Otieno, Lavender A., et al. "Intermittent Single-joint Fatiguing Exercise Reduces TMS-EEG Measures of Cortical Inhibition." Journal of Neurophysiology, vol. 121, no. 2, 2019, pp. 471-479.
Otieno LA, Opie GM, Semmler JG, et al. Intermittent single-joint fatiguing exercise reduces TMS-EEG measures of cortical inhibition. J Neurophysiol. 2019;121(2):471-479.
Otieno, L. A., Opie, G. M., Semmler, J. G., Ridding, M. C., & Sidhu, S. K. (2019). Intermittent single-joint fatiguing exercise reduces TMS-EEG measures of cortical inhibition. Journal of Neurophysiology, 121(2), pp. 471-479. doi:10.1152/jn.00628.2018.
Otieno LA, et al. Intermittent Single-joint Fatiguing Exercise Reduces TMS-EEG Measures of Cortical Inhibition. J Neurophysiol. 2019 02 1;121(2):471-479. PubMed PMID: 30565971.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intermittent single-joint fatiguing exercise reduces TMS-EEG measures of cortical inhibition. AU - Otieno,Lavender A, AU - Opie,George M, AU - Semmler,John G, AU - Ridding,Michael C, AU - Sidhu,Simranjit K, Y1 - 2018/12/19/ PY - 2018/12/20/pubmed PY - 2018/12/20/medline PY - 2018/12/20/entrez KW - TMS-EEG KW - cortical excitability KW - cortical inhibition KW - fatigue SP - 471 EP - 479 JF - Journal of neurophysiology JO - J. Neurophysiol. VL - 121 IS - 2 N2 - 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. SN - 1522-1598 UR - https://www.unboundmedicine.com/medline/citation/30565971/Intermittent_single_joint_fatiguing_exercise_reduces_TMS_EEG_measures_of_cortical_inhibition_ L2 - http://www.physiology.org/doi/full/10.1152/jn.00628.2018?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -