Effects of ECS following one-trial discriminated avoidance conditioning

Abstract

Because passive avoidance procedures confound the effects of electroconvulsive shock (ECS) on memory and the conditioned emotional response (CER), the present experiments used a discriminated avoidance technique in which response choice served as a relatively unequivocal indicator of retention. ECS slightly impaired discriminated avoidance in 4 experiments, although the magnitude of the impairment did not depend on the time interval between learning and ECS for intervals between 100 sec and about 1 hr. The effect of ECS on response latency, however, depended upon both the learning-ECS interval and the way in which Ss were tested. If testing was free choice, where Ss could repeat the punished response or make an alternative unpunished response, response latency decreased as the learning-ECS interval was lengthened. If testing was forced choice, where Ss were allowed only to repeat the punished response as in passive avoidance, the typical increasing latency gradient with increasing learning-ECS interval was obtained. Comparable latency gradients were obtained with both free and forced choice testing when Ss were tested at the various post-learning intervals rather than given an ECS. The results were interpreted as indicating that ECS given 100 sec to 1 hr after learning fails to affect memory consolidation but does interfere with the temporal development (incubation) of the CER.