OSCILLATORY BRAIN ACTIVITY DURING A MOTOR TASK

CHANGES in spectral power in neuromagnetic fields associated with a ma nual task requiring a high level of sensorimotor integration (SMI) wer e investigated by analysing spontaneous, non-invasively recorded activ ity during motor preparation (WAIT), task performance (SMI), and contr ol (REST) conditions in four healthy, right-handed human subjects. Neu romagnetic fields were recorded over the left sensorimotor cortex usin g a 37-channel instrument. In all subjects, a prominent narrow-band mo tor preparation rhythm centred near 19 Hz was consistently observed du ring the WAIT state. During SMI, mean relative increases in 26-30 Hz a ctivity appeared in two of the subjects, paralleling gamma band enhanc ement recently observed during SMI in monkeys.