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

Rita A. Fuchs, Suzanne M. Weber, Heather J. Rice, Janet Neisewander

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Abstract

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 μl/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.

Original languageEnglish (US)
Pages (from-to)15-25
Number of pages11
JournalBrain Research
Volume929
Issue number1
DOIs
StatePublished - Mar 1 2002

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Keywords

  • Basolateral amygdala
  • Cocaine
  • Cocaine-seeking behavior
  • Conditioned place preference
  • Incentive motivation
  • Stimulus-reward learning

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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