Discrimination Behavior and Conditioned Suppression (CER) following Localized Lesions in the Amygdala and Putamen

Abstract

In an effort to localize and interrelate amygdaloid functions in the rat required for (a) suppression of response during nonreinforced components of a discrimination and in extinction of response, and (b) those required for development of a conditioned emotional response (CER), lesions were prepared in different parts of the amygdaloid complex and overlying putamen. Large lesions of the amygdala blocked formation of the CER and interfered with response suppression under nonreinforced conditions but not to the extent of seriously disrupting discrimination performance. Putamen lesions, on the other hand, seriously disrupted discrimination performance but had no reliable effect upon CER. Results on subtotal amygdaloid lesions implicated the medial region in the area of basomedial and cortical and perhaps central nuclei in both the control of nonreinforced behavior and formation of the CER. The more lateral components of the amygdala appear less essential for these functions.