Cortical magnetic activation following voluntary movement and several types of somatosensory stimulation

Abstract

Magnetoencephalography is primarily sensitive to current sources tangential to the skull. Therefore, currents generated in area 3b of the primary somatosensory cortex (S1) and area 4 of primary motor cortex (M1) located on the posterior and anterior banks of the central sulcus, respectively, are easily detected. The movement-related cortical magnetic fields (MRCFs) following voluntary movement and the somatosensory magnetic fields (SEFs) generated by peripheral mixed nerve stimulation (e.g., median nerve) have been widely used to investigate the physiology of normal somatosensory cortical processing. Here, we describe the MRCFs produced by two types of movement (experiment 1) and the SEFs elicited by motor point stimulation (experiment 2), passive movement (experiments 3 and 4), and mechanical stimulation (experiments 5, 6, and 7). In addition, we examined the modulation of these fields.