A comparative evaluation of sudomotor innervation to the limbs and perineum was made using electrical stimulation of the median nerve at the wrist and transcranial magnetic stimulation of the brain. Sympathetic skin responses (SSRs) were recorded from the palms (SSR-1), the soles (SSR-2) and the perineum (SSR-3). Normative data in 25 volunteers showed the following latencies in seconds: [table: see text].