J Korean Acad Rehabil Med.  2006 Oct;30(5):436-440.

The After-effect of Sub-threshold 10 Hz Repetitive Transcranial Magnetic Stimulation on Motor Cortical Excitability

• Ko MH
• Jeong YC
• Seo JH
• Kim YH

Abstract

OBJECTIVE
To study the after effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex on cortical excitability METHOD: Twenty healthy volunteers received 1,000 stimuli of 10 Hz rTMS. Repetitive TMS was given over the 'motor hot spot' of the right first dorsal interosseus muscle using an intensity of 80% of resting motor threshold. We evaluated the amplitude of motor evoked potential (MEP) using single pulse TMS and intracortical inhibition and intracortical facilitation with paired pulse TMS paradigm. After baseline measurement, the amplitude was measured immediately after stimulation and 10, 20, 30 and 40 minutes after rTMS.
RESULTS
The amplitude of MEP was significantly increased for 10 minutes after applying 1,000 stimuli of 10 Hz rTMS. Additionally, intracortical inhibition was significantly reduced and intracortical facilitation was significantly enhanced for 10 minutes after 10 Hz rTMS.
CONCLUSION
These results showed that 1,000 stimuli of 10 Hz rTMS over primary motor cortex increased the corticospinal excitability for 10 minutes. In addition, 10 Hz rTMS induced a suppression of the intracortical inhibitory circuitry and facilitation of the excitatory circuity for 10 minutes.

Keyword

Repetitive transcranial magnetic stimulation; Motor cortex; Cortical excitability

MeSH Terms

Evoked Potentials, Motor
Healthy Volunteers
Motor Cortex
Transcranial Magnetic Stimulation*