THE PERIPHERAL MECHANISM OF THE GALVANIC SKIN RESPONSE

Darrow held that the galvanic skin response (GSR) appears to be a complicated phenomenon because a number of events are sequentially involved. The mechanism resulting in the peripheral components of electrodermal phenomena is not complicated. Following excitation, sympathetic impulses to cutaneous tissues and subsequent release of acetylcholine account for initial negative polarity and resistance changes. When these incoming impulses are sufficiently persistent and strong, and when the cholinergic response of the sweat glands is sufficient, then if temperature and circulatory conditions are favorable, secretion by the sweat glands is initiated. Sweating is the major factor contributing to the positive potential and large drops in skin resistance during excitation, but at low levels of excitation, when skin resistance is high and before sweating has reached a critical level, epidermal activities other than those of the sweat glands may contribute appreciably to negative potential and resistance changes.