Temporal and spatial dynamics of biomagnetic event-related desynchronization/synchronization during voluntary movement

We studied event-related desynchronization/synchronization (ERD/ERS) during voluntary movement. Ten healthy volunteers participated in this study and a whole head type magnetoencephalography (MEG) with 102 orthogonal paired planar type gradiometers was used. The task was self-paced right index finger extension by 10 s. Trigger point was set at rapid build up on electromyogram measured from right common digital extensor muscle. MEG data were processed through band-pass filter by 2 Hz (0-40 Hz) and bootstrap method with 95% confidence intervals. Processed data were projected over subjects' individual brain surface images and interpolated. Consecutive ERD/ERS brain surface images suggested there are at least three ERD/ERS patterns during voluntary movement. The first pattern is simple narrow beta band ERD, the second pattern is simple narrow beta band ERS, and the last pattern consists of preceding broad band ERD and following broad band ERS.