Abstract: | Short latency median nerve somatosensory evoked potentials (SEPs) were studied in two patients presenting with well localized unilateral pontine lesions producing hemisensory deficits. Both the early subcortical (N11-N13) and the later cortical component (N19-P22) of the SEP were abnormal in the patient whose lesion involved the medial lemniscus, while they remained unaffected in a second case of lateral inferior pontine infarction in which the medial lemniscus was spread. These results suggest that the N11-N13 component of the scalp recorded SEP emanates from the brain stem medial lemniscal pathway. |