MOTOR CORTEX ACTIVITY AND PREDICTING SIDE OF MOVEMENT - NEURAL-NETWORK AND DIPOLE ANALYSIS OF PRE-MOVEMENT MAGNETIC-FIELDS

Neuromagnetic fields were recorded from human subjects during the perf ormance of left and right voluntary finger movements. Modeling of curr ent dipole sources indicated symmetric activation of both motor cortic es beginning 600 ms prior to movement onset. This activity became late ralized to the contralateral hemisphere 200-300 ms prior to movement o nset, the period during which an artificial neural network showed incr eased ability to predict side of movement within single trials. The re sults describe the mechanism of lateralization of cortical brain activ ity preceding voluntary movement and provide further evidence of the i nvolvement of ipsilateral motor cortex in unilateral movements.