Different neuronal contribution to N20 somatosensory evoked potential and to CO2 laser evoked potentials: an intracerebral recording study

Abstract Objective : To investigate the possible contribution of the primary somatosensory area (SI) to pain sensation. Methods : Depth recordings of CO 2 laser evoked potentials (LEPs) and somatosensory evoked potentials (SEPs) were performed in an epileptic patient with a stereotactically implanted electrode (Talairach coordinates y =−23, z =40) that passed about 10 mm below the hand representation in her left SI area, as assessed by the source of the N20 SEP component. Results : The intracerebral electrode was able to record the N20 SEP component after non-painful electrical stimulation of her right median nerve. The N20 potential showed a phase reversal in the bipolar montage (at about …