Beta event-related synchronization after muscle contraction is modulated by voluntary movement patterns: An EEG and MEG study

Beta-band event-related synchronization (βERS) in the contralateral sensorimotor cortex is induced by voluntary movement and somatosensory input, suggesting its deep involvement in afferent information processing, but the precise generative mechanisms require further investigation. This study examined the contributions of joint movement to βERS following self-paced voluntary movement. The βERS was recorded from 15 healthy adults while performing a task involving contraction of the right extensor indicis proprius muscle with and without metacarpophalangeal joint movement using electroencephalography (EEG) and magnetoencephalography (MEG). In both joint movement and non-movement conditions, βERS amplitude was significantly greater than baseline, whether measured by EEG or MEG, but was significantly greater in the joint movement condition. In addition, βERS amplitude was significantly greater when measured by MEG. These findings suggest that, in addition to changes in muscle tension, afferent inputs associated with changes in joint position may contribute to the increase in βERS amplitude. The stronger βERS detected by MEG further suggests that neuronal activity in cortical sulci is a major contributor to βERS generation. This study provides new insights into the physiological mechanisms underlying βERS.