Neocortico-amygdalar interaction in the conditioned taste aversion in rats

Corticoamygdalar interaction in the acquisition and retrieval of the conditioned taste aversion (CTA) was studied in rats by combination of unilateral lesion of basolateral amygdala with unilateral functional decortication by cortical spreading depression (CSD). Sodium saccharin (0.1%, 15 min) served as the CS, intraperitoneal injection od LiCl (0.15 M, 4% body weight) as the US. The CS-US delay was 20 min. Aversion was tested by measuring sacharin consumption 5 days later. Marked CTA was found in the unoperated and in the unilaterally lesioned controls. Amygdalectomized rats subjected during CTA acquisition to unilateral CSD ipsilateral or contralateral to the lesion, drank less saccharin and developed weaker CTA than the controls. Retrieval of CTA acquired by undepressed operated animals was prevented by funcitonal hemidecortication of the intact but not of the lesioned hemisphere. It is concluded that ipsilateral connections between neocortex and basolateral amygdala are more important for retrieval than for acquisition of CTA.