Amygdala central nucleus lesions disrupt increments, but not decrements, in conditioned stimulus processing

Abstract

The effects of neurotoxic lesions of the amygdala central nucleus (CN) on changes in the associability of a conditioned stimulus (CS) in appetitive Pavlovian conditioning were examined in 2 experiments with rats. In Experiment 1, CN lesions had no effect on the reduction in the associability of a CS produced by preexposure to that cue (latent inhibition). In Experiment 2, CN lesions prevented the enhancement of the associability of a CS that is normally observed when an inconsistent predictive relation is arranged between that CS and another cue. The results support previous claims that the amygdala CN is involved in broad-based incremental, but not decremental, changes in the processing of CSs in Pavlovian conditioning.