Lesions of the basolateral amygdala disrupt selective aspects of reinforcer representation in rats

The amygdala is known to play a role in learning about motivationally signi ficant events. We investigated this role further by examining the effects o f excitotoxic lesions of the basolateral amygdala on the ability of rats to use instrumental outcomes to direct responding (the differential outcomes effect) and on the ability of Pavlovian cues to modulate instrumental perfo rmance based on shared outcomes (reinforcer-selective Pavlovian-to-instrume ntal transfer). We found that basolateral amygdala (BLA) lesions did not af fect the ability of rats to learn a basic instrumental conditional discrimi nation, but did disrupt the ability of differential outcomes to facilitate acquisition. In Pavlovian-to- instrumental transfer, BLA lesions did not di srupt the basic enhancement of instrumental performance but did abolish the reinforcer specificity of that enhancement. These results suggest that the BLA is involved in the representation of the sensory aspects of motivation ally significant events.