[Functional dissociation of parts of the "sensorimotor complex" in the human cortex with the method of magnetoencephalography].

A method of non-invasive human primary motor cortex mapping has been developed. In 18 healthy right-handed subjects magnetic brain responses caused by repeated voluntary left or right index finger movements were studied. Movement onsets were derived from the accelerometer signal. Recordings of magnetic activity throughout whole experimental sessions in all subjects were concatenated into a single sequence, which was separated into independent components using independent component analysis and ranked according to the amount of mutual information with the modified accelerometer signal. Independent components that demonstrated maximum relation to the finger movement were averaged relative to the movement onset. The results of the distributed brain source modeling of the two independent components that manifested maximum amount of mutual information has demonstrated that their sources localize in the cortical areas corresponding to anatomical markers of hand representation in the primary motor and the primary sensory cortices contralateral to the movement. The method developed has demonstrated the fundamental possibility of localizing the M1 area in healthy subjects.