Place Conditioning to Study Drug Reward and Aversion

Place conditioning is a classical conditioning paradigm in which animals (typically rats or mice) learn to associate the effects of a drug (or other discrete treatment) with a particular environment. Although it is often referred to as the “Conditioned Place Preference (CPP)” paradigm, this designation fails to capture the flexibility of the assay: it identifies both conditioned place preferences and conditioned place aversions, and thus it can be used to study both rewarding drug effects and aversive drug effects. There are several comprehensive place conditioning reviews in which methodology is described, results are summarized, and the theoretical underpinnings of the behavior are discussed (1 –3 ). The purpose of this chapter is to describe methodology that, at least in rats, minimizes training time and maximizes the sensitivity of the assay to reward, diminished reward (anhedonia), and aversion. As such, place conditioning can be used as a relatively high-throughput assay to study addiction (4 –7 ) and other neuropsychiatric disorders involving brain reward systems, including depression (8 ,9 ).