Effects of high frequency repetitive transcranial magnetic stimulation on P 300 event-related potentials

Abstract

Objective: Auditory event-related potentials (P 300-ERPs) were analyzed before and after repetitive transcranial magnetic stimulation (rTMS). Methods: Two rTMS trains (10 Hz, 3 s, 100% motor threshold and 5 min interval) were delivered over the left frontal area in healthy subjects. P 300-ERPs were recorded at 14 electrode sites on the scalp using a typical oddball paradigm before and after rTMS. The latencies and amplitudes of N 100, P 200, N 200 and P 300 were measured and compared. The directed coherence (DCOH) was estimated to demonstrate information flow between different cortical areas. Results: rTMS significantly influenced P 300-ERPs. The effects differed on the different components ( P<0.001). The latency of P 300 significantly increased after stimulation, which was more obvious in the frontal and central areas. The changes in P 300 amplitude were not significant ( P>0.05). The DCOH from the frontal, central, parietal and occipital areas to the temporal area was significantly higher than the DCOH from the temporal area to the former 4 areas ( P<0.01). Conclusions: rTMS with the present parameters can affect P 300-ERPs, leading to a delayed P 300 component and changes in information connections around the stimulated site. Our data suggest that rTMS may postpone neuronal activities related to cognitive processing.