Excessive incentive salience (‘wanting’/desire) in some individuals has also been posited to play a role in eating disorders and obesity. Obesity is especially prevalent in a modern junk food environment. In a recent collaboration with researchers at the University of Michigan, including Carrie Ferrario in the Department of Pharmacology, we have examined an animal model of excessive incentive salience and obesity induced by junk food. Some rats given a sweet and high fat ‘junk food’ diet become intensely obese, whereas other individuals remain at normal weight. The individuals that become obese also come to attribute higher incentive salience to sucrose cues, becoming less likely to ignore food cues in extinction and seeking out the cues more in an instrumental conditioned reinforcement paradigm. We are also examining the before vs. after time course of incentive salience and brain signatures to find out whether vulnerable individuals start out with higher ‘wanting’ or become changed over time by their experiences with junk food. Our aim is also to examine the effects of early-life and maternal exposure to a junk food diet and how this may affect the attribution of incentive salience to reward related cues.