An enhanced level of motor cortical excitability during the control of human standing

Tokuno, C. D., Taube, W. and Cresswell, A. G. (2009) An enhanced level of motor cortical excitability during the control of human standing. Acta Physiologica, 195 3: 385-395. doi:10.1111/j.1748-1716.2008.01898.x

Author Tokuno, C. D.
Taube, W.
Cresswell, A. G.
Title An enhanced level of motor cortical excitability during the control of human standing
Journal name Acta Physiologica   Check publisher's open access policy
ISSN 1748-1708
Publication date 2009-03-01
Year available 2008
Sub-type Article (original research)
DOI 10.1111/j.1748-1716.2008.01898.x
Volume 195
Issue 3
Start page 385
End page 395
Total pages 11
Editor Jan Henriksson
Place of publication Oxford, U.K
Publisher Blackwell Publishing for the Scandinavian Physiological Society
Language eng
Subject C1
920111 Nervous System and Disorders
110601 Biomechanics
1109 Neurosciences
Formatted abstract
Aim: The study examined the role of the motor cortex in the control of human standing.

Methods: Subjects (n = 15) stood quietly with or without body support. The supported standing condition enabled subjects to stand with a reduced amount of postural sway. Peripheral electrical stimulation, transcranial magnetic stimulation (TMS) or transcranial electrical stimulation (TES) was applied to elicit a soleus (SOL) H-reflex, or motor-evoked potentials (MEPs) in the SOL and the tibialis anterior (TA). Trials were grouped based on the standing condition (i.e. supported vs. normal) as well as sway direction (i.e. forward and backward) while subjects were standing normally.

Results: During normal when compared to supported standing, the SOL H-reflex was depressed (−11 ± 4%), while the TMS-evoked MEPs from the SOL and TA were facilitated (35 ± 11% for the SOL, 51 ± 15% for the TA). TES-evoked SOL and TA MEPs were, however, not different between the normal and supported standing conditions. The data based on sway direction indicated that the SOL H-reflex, as well as the SOL TMS- and TES-evoked MEPs were all greater during forward when compared to backward sway. In contrast, the TMS- and TES-evoked MEPs from the TA were smaller when swaying forward as compared to backward.

Conclusions: The results indicated the presence of an enhanced cortical excitability because of the need to control for postural sway during normal standing. The increased cortical excitability was, however, unlikely to be involved in an on-going control of postural sway, suggesting that postural sway is controlled at the spinal and/or subcortical levels.
© 2008 The Authors
Journal compilation © 2008 Scandinavian Physiological Society

Keyword H-reflex
Transcranial Magnetic Stimulation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Article first published online: 4 SEP 2008

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Health and Rehabilitation Sciences Publications
School of Human Movement and Nutrition Sciences Publications
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Citation counts: TR Web of Science Citation Count  Cited 43 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 24 Nov 2009, 09:21:47 EST by Deborah Noon on behalf of School of Human Movement and Nutrition Sciences