Three-electrode method to study event-related responses in skin electrical potential, admittance and blood flow.

Abstract

To investigate a broader spectrum of responses to the activity of efferent sympathetic nerve endings in blood vessels and sweat glands of the human palmar skin, we have developed a method to measure skin potential, skin unipolar electrical admittance (conductance and capacitance), skin blood flow, and skin temperature simultaneously at the same site of human palmar skin. The electrical variables were measured with a specially designed probe and a three electrode lock-in amplifier measuring system. The aim of the paper is to evaluate this method and its potential application in clinical work. The experimental results from five subjects during 5 min of baseline condition and during repeated acoustic stimulation are presented. The skin temperature was displayed digitally. During basal condition the activities in skin electrical variables and in blood vessel vasomotion were largely independent (asynchronous), whereas efferent sympathetic discharges due to stimulation were followed by parallel evoked responses in skin admittance, skin potential and skin blood flow. Habituation to the repeated stimuli occurred differently in the four variables.