Stimulus Site Effects on Skin Conductance Responses From the Volar Surfaces

Pulse trains were applied separately to each forefinger and to each hallux of 23 Ss to assess stimulus site effects on the relative amplitudes of skin conductance responses recorded concurrently from each palm and from each plantar surface. A binaurally presented tone was used as a non-lateralized stimulus. Analyses of the ratio of response amplitudes from contralateral recording sites indicated that for both the upper and lower extremities, responses from the volar surface of the stimulated extremity were augmented in amplitude. Responses from the volar surface of the extremity ipsilateral to the stimulus and recording sites involved the same extremity. Analyses of the ratio of response amplitudes from the palmar and plantar surfaces on the same side of the body indicated that the specific effects of stimulation did not cross the body midline. The results were interpreted as indicating a regionally differentiated sympathetic outflow to the volar sweat glands that reflects the locus of cutaneous stimulation.