Bilateral Differences in Skin Resistance and Vasomotor Activity

Bilateral basal skin resistance (BSR) and bilateral photoplethysmographic vasomotor measures were obtained for 16 Ss. Ten Ss were found to have bilateral differences in BSR. The direction of these differences was not related to handedness. Bilateral differences in vasomotor resting levels, variability, and reactivity were also observed in the majority of Ss. Some relationships among bilateral patterns of vasomotor responsivity and BSR emerged. Thus, the side of the body having lower BSR was identical to the side with the lesser vasomotor constriction during experimental stress (breath holding). Also, the side of the body having the lower vasomotor amplitude had less vasomotor variability. The findings suggest that asymmetry of autonomic activity is typical rather than atypical for the normal individual, and that various autonomic variables form patterns of asymmetry.