Event-related synchronization of mu rhythm in the EEG over the cortical hand area in man.

Spontaneous EEG activity was recorded at 56 electrodes in 3 healthy subjects. All subjects displayed event-related desynchronization (ERD) of mu rhythms over the cortical hand area during discrete finger movement. In contrast to this, foot movement resulted in an enhancement or event-related synchronization (ERS) of mu rhythms over the hand area. This phasic synchronization of mu waves was circumscribed and found at electrodes overlying both cortical hand areas. It is speculated, that this ERS represents a short lasting 'idling state' of hand area neurons when other body parts are moved.