Document Detail

Increased primary motor cortical excitability by a single-pulse transcranial magnetic stimulation over the supplementary motor area.
MedLine Citation:
PMID:  22532164     Owner:  NLM     Status:  MEDLINE    
The supplementary motor area (SMA) is a secondary motor area that is involved in various complex hand movements. In animal studies, short latency and probably direct excitatory inputs from SMA to the primary motor cortex (M1) have been established. Although human imaging studies revealed functional connectivity between SMA and M1, its electrophysiological nature has been less studied. This study explored the connection between SMA and M1 in humans using a single-pulse transcranial magnetic stimulation (TMS) over SMA. First, TMS over SMA did not alter the corticospinal tract excitability measured by the size of motor evoked potential elicited by single-pulse TMS over M1. Next, we measured short-interval intracortical facilitation (SICF), which reflects the function of a facilitatory circuit within M1, with or without a single-pulse TMS over SMA. When the intensity of the second pulse in the SICF paradigm (S2) was as weak as 1.0 active motor threshold for a hand muscle, SMA stimulation significantly enhanced the SICF. Furthermore, this enhancement by SMA stimulation was spatially confined and had a limited time window. On the other hand, SMA stimulation did not alter short-interval intracortical inhibition or contralateral silent period duration, which reflects the function of an inhibitory circuit mediated by gamma-aminobutyric acid A (GABA(A)) or GABA(B) receptors, respectively. We conclude that a single-pulse TMS over SMA modulates a facilitatory circuit within M1.
Yuichiro Shirota; Masashi Hamada; Yasuo Terao; Shinya Ohminami; Ryosuke Tsutsumi; Yoshikazu Ugawa; Ritsuko Hanajima
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-04-25
Journal Detail:
Title:  Experimental brain research     Volume:  219     ISSN:  1432-1106     ISO Abbreviation:  Exp Brain Res     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-05-24     Completed Date:  2013-03-11     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  339-49     Citation Subset:  IM    
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MeSH Terms
Evoked Potentials, Motor / physiology*
Frontal Lobe / anatomy & histology,  physiology*
Middle Aged
Motor Cortex / anatomy & histology,  physiology*
Neural Pathways / anatomy & histology,  physiology*
Transcranial Magnetic Stimulation / methods*

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