Subthreshold 5-Hz repetitive transcranial magnetic stimulation of the human primary motor cortex reduces intracortical paired-pulse inhibition.
Paired-pulse transcranial magnetic stimulation (TMS) at short interstimulus intervals was employed to investigate short-term effects of 5-Hz repetitive TMS (rTMS) over the primary motor hand area (M1(HAND)) on intracortical excitability. In ten healthy individuals, 1250 pulses of 5-Hz rTMS were applied at 90% of motor resting threshold over the left M1(HAND). Ten minutes after 5-Hz rTMS, paired-pulse inhibition was significantly reduced, whereas paired-pulse facilitation was not modified. Sham-rTMS had no lasting effect on intracortical excitability. These findings suggest that subthreshold 5-Hz rTMS causes a short-term modulation of the excitability of intracortical circuitry in the stimulated M1(HAND). The lasting effect of subthreshold 5-Hz rTMS on intracortical inhibition provides a useful probe for studying short-term plasticity of the human M1(HAND).
Peinemann
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A
Department of Neurology, Technische Universität München, D-81675, Munich, Germany. alexander.peinemann@neuro.med.tu-muenchen.de
Lehner
C
C
Mentschel
C
C
Münchau
A
A
Conrad
B
B
Siebner
H R
HR
D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D055590:Electromagnetic Phenomena; D004576:Electromyography; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000294:innervation; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation*; D013997:Time Factors