Effects of nucleus basolateralis amygdalae neurotoxic lesions on aversive conditioning in the rat.

After bilateral stereotaxic administration of ibotenic acid on the n. basolateralis amygdalae, male adult rats were tested in the light-dark box apparatus to measure the time-course of the acquisition and retention of passive and active avoidance responses. The results show that after the lesions both passive avoidance and active avoidance acquisition were impaired. Passive avoidance responses were retained quite well, while active avoidance responses disappeared quickly. Conditioned freezing was almost completely absent. Thus it appears that the n. basolateralis plays a facilitatory role in all the conditioned responses which were investigated.