抄録
Distribution of cortico-muscular coherence was investigated between local field potential of primary motor (M1) cortex with distal and proximal forearm representations and EMG of various forearm muscles in a macaque monkey during performance of the precision grip task. Muscle field of the recording sites in M1 was assessed by the stimulus triggered averaging of the EMG activities with the stimulus intensity below 40 μA with single pulses. We have found that M1 sites that have muscle field in the distal muscles showed clear task-related β band coherent activity (15–30 Hz) with EMG of the distal muscles. However, the sites that have muscle fields in proximal muscles showed no coherence with proximal muscles, but showed clear coherence with distal muscles. Even if we increased the stimulus intensity up to 40 μA and applied repetitive stimulus (20 pulses at 333 Hz), no post-stimulus effect could be observed in distal muscles from these sites. We conclude that task-related β coherent activity in M1 areas of both distal and proximal muscle representation may engage networks of neurons controlling the distal muscles. [J Physiol Sci. 2007;57 Suppl:S160]
