The origin of the scalp recorded P14 following electrical stimulation of the median nerve: intraoperative observations.

Direct and far-field recorded somatosensory evoked potentials (SEPs) obtained from 2 patients during neurosurgical procedures are presented. A previous report (Møller et al. 1986) has suggested that the P14 component of the SEP following median nerve stimulation is generated at the cuneate nucleus. The present data suggest that the scalp recorded P14 component (scalp-noncephalic electrode derivation) is generated rostral to the junction of the cervical cord and the medulla.