Abstract
The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effect of low-frequency and short-term rTMS. We investigated the effect of P300 latency by 1.0 or 0.5 rTMS over the supramarginal gyrus (SMGs) and dorsolateral prefrontal cortex (DLPFCs). The P300 of ERP was elicited by auditory odd-ball task, which was delivered before and shortly after rTMS. ERP was measured prior to rTMS as a control, and after the rTMS. The rTMS was performed for 100 pulses. We found that the individual frequency difference of rTMS affected P300 latencies. Compared to the control, with 1.0 Hz-rTMS to the left-SMG, P300 latencies decreased. Latencies were shorted by approximately 18 ms at Fz electrode. With 0.5 Hz-rTMS to the left-SMG and 1.0 Hz-rTMS to the left-DLPFC, P300 latencies increased. Latencies were lengthened by approximately 26 ms at Fz electrode with 0.5 Hz-rTMS to the left-SMG, and by approximately 18 ms at Fz electrode with 1 Hz-rTMS to the left-DLPFC. In contrast, P300 latency was little altered by rTMS over the right-SMG and right-DLPFC. The results suggested that the effect of low-frequency rTMS had difference by stimulus frequency and stimulation point.
