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

Objective: To study the aftereffects ghrepetitive transcranial magnetic stimulation (rTIVIS) primary motor cortex on cortical excitability Method: Twentyhealthyvolunteers received 1,000stimuli of 10 Hz rTMS. Repetitive mils 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 was measurement, the amplitude as 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 1,000stimuli of 0 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.