Assessing both Primary Motor and Somatosensory Cortexes using Neuromagnetic Median Nerve Task

In the past, hemiplegia or hemiparesis after primary motor cortex (MI) damage made it difficult to evaluate the neurophysiological basis for restoration of motor function using functional imaging technologies. This is because traditional assessments of MI tissue viability have depended on measurements requiring movement of the fingers, hand, or limb, which is either impossible or significantly compromised in patients with these disorders. In this paper, we will first review our recent findings in healthy subjects using magnetoencephalography (MEG), a non-invasive neuromagnetic functional imaging technique, to show that electrical median nerve stimulation is a reliable procedure for eliciting activity in MI, as well as primary somatosensory cortex (SI). The rationale underlying this approach was suggested by neuronal interconnectivity of MI. Then, we will present the results of using median nerve MEG task on acute ischemic stroke patients to monitor the patients ’ primary motor, as well as somatosensory functions, when they have difficulties in performing the traditional active motor tasks