Measurements of BEG Evoked by Transcranial Magnetic Stimulation at Various Stimulus Points on the Head

The combined measurement of EEG and transcranial magnetic stimulation (TMS) in an effective method for investigating the cortical activity and the functional connectivity in the brain. This study focused on the differences in the cortical activity of motor area, posterior parietal cortex and cerebellum when the TMS was applied to each area. The EEG over the whole head was measured, and the EEG topography and current distribution was obtained. In a part study, when motor area was stimulated by TMS, it was observed that the spreading of the EEG response to the contralateral hemisphere in about 20 mn[1]. In order to investigate the relationship between the stimulus point and the evoked potential, the stimulus points were selected at motor area, posterior parietal cortex and cerebellum. We observed the difference in cortical activity of motor area, posterior parietal cortex and cerebellum. When motor area was stimulated, transmitting of the cortical activity from the stimulated hemisphere to the contralateral hemisphere was observed. However, when posterior parietal cortex was stimulated, such transmitting was not observed.