Modulation of the magnitude of conditioned taste aversion in rats with excitotoxic lesions of the basolateral amygdala.

The amygdala is one of the structures involved in the acquisition of conditioned taste aversion (CTA). Nevertheless, the specific roles that the nuclei of this structure play in CTA learning are controversial. Electrolytic lesions applied to the basolateral nucleus of the amygdala can eliminate or reduce the acquisition of this learning. This effect has been attributed to the involvement of fibers that pass through this nucleus and connect with other structures that are critical for CTA. Excitotoxic lesions may allow a clearer insight as to the potential involvement of this nucleus in the acquisition of CTA. The few studies to date that have used this paradigm have shown effects on taste aversion learning after applying extensive lesions to the amygdala. Thus, the aim of the present study was to determine the effect of selective excitotoxic lesions of the basolateral amygdala on the acquisition of CTA. The effects of these lesions on learning were compared with the effects observed in animals with sham lesions and animals with lesions of the hippocampus, which is a structure apparently not involved in CTA. The results revealed a decreased aversion in animals with basolateral lesions compared with both the sham and hippocampus-lesioned groups. Based on these findings, the role of this specific nucleus of the amygdala in the acquisition of taste aversion is briefly discussed.