New depth short-latency somatosensory evoked potential (SEP) component recorded in human SI area

To analyse short and long-latency (SEPs) recorded by chronically stereotactically electrodes implanted in SI area of two epileptic patients. Two drug-resistant epileptic patients (2 females, 38 and 15 years, respectively) suffering from left temporal and right frontal epilepsy respectively, were investigated by an electrode-chronically implanted in SI area. Short and long latency somatosensory evoked potentials were recorded by depth electrodes 10 days after implantation. This is the first study to describe a depth N36 response by an intracerebral recording electrode in the SI area, probably generated by a radially oriented generator, located in area 1. Furthermore, we confirmed a role of SI in the genesis of N60 component. Finally, our present data suggest that the SI area is still active at 120 ms after the stimulus, since in one patient (no. 2) we identified a N120 potential, reaching its maximal amplitude at the same depth as the N20 response.