Pairings of lever and food induce Pavlovian conditioned approach of sign-tracking and goal-tracking in C57BL/6 mice.

In rats, Pavlovian sign-tracking has been extensively evaluated as a model of compulsiveness in drug addiction and other addictive behaviors, but it remains unexplored in mice, a species with a wealth of genetically modified models, which makes it possible to examine gene-behavior relationships. In C57BL/6 mice, the most commonly used mouse strain for genetic studies, repeated pairings of lever conditioned stimulus (CS) with food unconditioned stimulus (US) induced Pavlovian conditioning of sign-tracking conditioned response (ST CR) performance of lever CS-directed approach, and Pavlovian conditioning of goal-tracking conditioned response (GT CR) performance of approach responses directed at the location of the food trough where the food US was delivered. The CS-US Paired group performed more ST CRs and more GT CRs during sessions 15-16 than did pseudoconditioning controls which received the lever CS and food US randomly with respect to one another.