Effects of excitotoxic lesions of the basolateral amygdala on cocaine-seeking behavior and cocaine conditioned place preference in rats

Brain Res. 2002 Mar 1;929(1):15-25. doi: 10.1016/s0006-8993(01)03366-2.


Incentive motivation for cocaine, elicited by cocaine-associated stimuli, is thought to be involved in craving and relapse. To examine the role of the basolateral amygdala complex (BLC) in this phenomenon, we assessed the effects of post-training BLC lesions on extinction of cocaine-seeking behavior and cocaine-conditioned place preference (CPP) and the effects of pre-training BLC lesions on acquisition of cocaine-CPP. In Experiment 1, rats were first trained to self-administer cocaine and then received bilateral infusions of the excitotoxin, N-methyl-D-aspartic acid (NMDA, 0.12 M; 0.3 microl/side), or vehicle into the BLC. They were then tested repeatedly for extinction of cocaine-seeking behavior (i.e. nonreinforced responses in the presence of cocaine-paired stimuli). Subsequently, they were trained and tested for acquisition of cocaine-CPP (i.e. increased time spent in a previously cocaine-paired, relative to a saline-paired, environment). Locomotion and compartment entries were also measured. In Experiment 2, rats were first trained and tested for cocaine-CPP, and then received NMDA or vehicle infusions into the BLC. Subsequently, they were tested repeatedly for extinction of cocaine-CPP. Post-training BLC lesions retarded extinction of cocaine-seeking behavior and cocaine-CPP, whereas pre-training lesions disrupted acquisition of cocaine-CPP. These effects did not appear to be related to changes in general activity. We suggest that pre-training BLC lesions disrupted acquisition of cocaine-CPP by impairing assignment of incentive value to cocaine-paired stimuli, whereas post-training BLC lesions disrupted extinction of cocaine-conditioned behaviors by impairing the assessment of the current incentive value of cocaine-paired stimuli.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amygdala / drug effects*
  • Amygdala / physiology
  • Animals
  • Cocaine / pharmacology*
  • Cocaine-Related Disorders / pathology
  • Cocaine-Related Disorders / physiopathology*
  • Conditioning, Psychological / drug effects*
  • Conditioning, Psychological / physiology
  • Denervation
  • Discrimination Learning / drug effects*
  • Discrimination Learning / physiology
  • Exploratory Behavior / drug effects*
  • Exploratory Behavior / physiology
  • Extinction, Psychological / drug effects
  • Extinction, Psychological / physiology
  • Male
  • Motor Activity / drug effects
  • Motor Activity / physiology
  • Neurotoxins / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Reward*
  • Self Administration / psychology


  • Neurotoxins
  • Cocaine