Linked Life Data

11685398

Source:http://linkedlifedata.com/resource/pubmed/id/11685398

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-10-30
pubmed:abstractText
Trains of repetitive transcranial magnetic stimuli (rTMS) appear to have effects on corticospinal excitability that outlast the duration of the train. In order to investigate the mechanism of this effect in more detail we applied short periods of rTMS consisting of up to 20 stimuli at 5 Hz, 10 Hz or 20 Hz (rTMS) to the motor cortex at an intensity equal to resting threshold in 11 healthy, relaxed subjects. Spinal excitability, as judged by effects on the H-reflex or on transcranial anodal facilitation of the H-reflex, was not affected by the rTMS. However, cortical excitability, as judged by the effect on the size of EMG responses evoked by a suprathreshold TMS pulse, was decreased for up to 1 s after the end of rTMS. Post-train suppression was more powerful following longer trains or higher frequencies of rTMS. The predominant suppression contrasts with previous reports of facilitation, particularly after high-frequency rTMS. A second set of experiments, however, showed that this could be converted into facilitation if the intensity of rTMS was increased. We conclude that the after-effects of rTMS depend on its frequency, intensity and duration. The results are consistent with a model in which inhibition and facilitation build up gradually during the course of a conditioning train. Inhibition reaches its maximum effect after only a small number of stimuli, whereas facilitation takes longer. The threshold for evoking inhibition is lower than that for facilitation. Thus if moderate intensities of conditioning train are applied, inhibition is predominant after short trains, whereas facilitation dominates after long trains.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0014-4819
pubmed:author
pubmed:issnType
Print
pubmed:volume
140
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
453-9
pubmed:dateRevised
2009-11-11
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Motor cortex excitability following short trains of repetitive magnetic stimuli.
pubmed:affiliation
Sobell Department of Neurophysiology, The Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't