Lesions of the basolateral amygdala abolish the ability of drug associated cues to reinstate responding during withdrawal from self-administered cocaine

This study investigated the ability of bilateral excitotoxic lesions of the basolateral amygdala (BLA) to disrupt cocaine self-administration, responding during extinction sessions, and stimulus cued recovery of extinguished responding in rats. BLA and sham lesions following 7 days of 3 h limited access cocaine self-administration sessions (0.33 mg/infusion) on a fixed ratio I (FR1) schedule of reinforcement failed to alter cocaine intake and responding on 7 subsequent days of self-administration. This lack of effect suggests that the BLA is not paramount for the maintenance of cocaine's reinforcing effects. In contrast, BLA lesions, but not sham lesions, following 7 or 14 days of cocaine self-administration attenuated responding on a lever associated with cocaine infusions on the first day of extinction sessions and blocked the ability of drug associated stimuli to reinstate extinguished responding following 20 daily extinction sessions. However, lesions of the BLA did not attenuate stimulus cued recovery of responding following 43 days of withdrawal. These results are consistent with the hypothesis that the BLA is important for the conditioned incentive properties of reinforcers, but not primary reinforcement itself. (C) 1997 Elsevier Science B.V.