Observing the Evoked Thumb Sensation under TENS in the Cerebral Cortex by MEG

Abstract

After amputation, the somatosensory cortex corresponding to lost fingers might be invaded by other cortical areas due to cerebral plasticity. However, it was seldom observed how the amputees could feel the evoked tactile sensation in the cerebral cortex under transcutaneous electrical nerve stimulation (TENS). By using magnetoencephalography (MEG), we investigated the cortical response under TENS of the evoked thumb territory and normal thumb. It was found that the maximum positive peak latencies of the event-related magnetic field were 60 ± 1.41 ms for the evoked thumb and 46 ± 1.25 ms for the normal counterpart. The strongest Equivalent Current Dipole (ECD) corresponding to evoked thumb was located in the central sulcus. And the lost-finger tactile sensation via TENS of the evoked finger territories was produced in the cerebral cortex near the mirror location of the normal thumb counterpart.