Document Detail

Mechanisms of motor-evoked potential facilitation following prolonged dual peripheral and central stimulation in humans.
MedLine Citation:
PMID:  11731592     Owner:  NLM     Status:  MEDLINE    
1. Repetitive electrical peripheral nerve or muscle stimulation can induce a lasting increase in the excitability of the corticomotor projection. By pairing peripheral stimulation with transcranial magnetic brain stimulation it is possible to shorten the duration of stimulation needed to induce this effect. This ability to induce excitability changes in the motor cortex may be of significance for the rehabilitation of brain-injured patients. The mechanisms responsible for the increases in excitability have not been investigated thoroughly. 2. Using two paired transcranial magnetic stimuli protocols we investigated the excitability of intracortical inhibitory and excitatory systems before and following a period of repetitive dual muscle and brain stimulation. The dual stimulation consisted of motor point stimulation of first dorsal interosseous (FDI; 10 Hz trains of 1 ms square waves for 500 ms) delivered at one train every 10 s, paired with single transcranial magnetic stimulation given 25 ms after the onset of the train. 3. Following 30 min of dual stimulation, motor-evoked potentials (MEPs) were significantly increased in amplitude. During this period of MEP facilitation there was no significant difference in the level of intracortical inhibition. There was, however, a significant increase in the intracortical facilitation demonstrated with paired magnetic stimuli. The increase in facilitation was seen only at short interstimulus intervals (0.8-2.0 ms). These intervals comprised a peak in the time course of facilitation, which is thought to reflect I wave interaction within the motor cortex. 4. The relevance of this finding to the MEP facilitation seen following dual peripheral and central stimulation is discussed.
M C Ridding; J L Taylor
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of physiology     Volume:  537     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2001 Dec 
Date Detail:
Created Date:  2001-12-03     Completed Date:  2002-02-11     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  623-31     Citation Subset:  IM    
Department of Medicine, Royal Adelaide Hospital, Adelaide 5000, Australia.
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MeSH Terms
Electric Stimulation / methods
Evoked Potentials, Motor*
Motor Cortex / physiology*
Muscle, Skeletal / physiology*
Peripheral Nerves / physiology*
Recruitment, Neurophysiological
Time Factors

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