Inhibitory learning tests of conditioned stimulus associability in rats with lesions of the amygdala central nucleus.

Normal rats showed faster inhibitory learning about a light conditioned stimulus (CS) if it had previously been an inconsistent predictor of a tone CS than if it had been a consistent predictor of the tone. In contrast, the inhibitory learning of rats with ibotenic acid lesions of the amygdala central nucleus (CN) was unaffected by the prior predictive value of the light. These results support claims that the CN is critical to surprise-induced enhancement of attentional processing of CSs.