Some Effects of Prior Experience with Electric Shock on the Acquisition of a Conditioned Emotional Response

Abstract

This thesis is concerned with the effects of previous ex­perience with electric shock on the acquisition of a conditioned emotional response (CER) to a signal preceding shock. Rats with prior shock experience were slow to acquire the normal CER, which is manifested by a decrease in the rate of food-motivated lever pressing. However, this slow acquisition did not seem to result from adaptation or habituation to shock, as had previously been proposed. Rather, prior experience with unsignalled shock tended in itself to inhibit the rate of lever pressing. When later presented with a warning signal preceding shock, rats with prior shock ex­perience increased their rate of responding. This "dis-inhibition" persisted for several days, after which the usual decrease in rate occurred.