Footshock facilitates the expression of aversively motivated memory in rats given post-training amygdala basolateral complex lesions

Abstract

We previously reported that increased training in an escape task partially attenuates the memory impairment produced by large amygdala lesions induced 1 week following training. The present study examined the effect of amount of preoperative training on the retention of rats with lesions restricted to the amygdala basolateral complex. Rats received 1 or 10 training trials in a footshock-motivated escape task and 1 week later sham lesions or neurotoxic lesions of the basolateral complex. Four days after recovery from the surgery they were tested for inhibitory avoidance retention and then 2 days later given continuous multiple trial inhibitory avoidance training (CMIA) in the same apparatus. The basolateral complex lesions significantly decreased the retention latencies of rats given 1 or 10 trials. However, following administration of footshock on the CMIA task, the performance of the lesioned rats reflected the degree of preoperative escape training. The basolateral complex lesions also increased open field locomotor activity, an effect that may have contributed to the shorter retention latencies in lesioned animals. These findings indicate that an intact amygdala basolateral complex is not critical for the retention of the escape training.