Double dissociation of the effects of lesions of basolateral and central amygdala on conditioned stimulus-potentiated feeding and Pavlovian-instrumental transfer

Pavlovian conditioned stimuli (CSs) for food can enhance both the performance of instrumental responses that earn food (Pavlovian-instrumental transfer; PIT) and the consumption of food itself (CS-potentiated feeding). After a single phase of Pavlovian training, each rat was tested in both PIT and potentiated feeding tasks. Rats with lesions of the central nucleus of the amygdala failed to exhibit PIT but showed normal CS-potentiated feeding. By contrast, rats with lesions of the basolateral amygdala showed normal PIT but failed to display CS-potentiated feeding. Performances in a variety of comparison conditions suggested that both lesion effects reflected impairment of acquired motivational functions, rather than with attentional processes or the display of specific learned responses. Implications of the double dissociation of these two aspects of Pavlovian conditioned incentive motivation for amygdala function in associative learning are considered.