Our research focuses on brain mechanisms of motivation and reward, especially related to neural generators of reward ‘wanting’ (incentive salience) and ‘liking’ (hedonic impact). We are particularly interested in how pathological function in these systems can lead to excessive motivation and addiction. Our studies combine optogenetic manipulations (such as stimulating neural systems via viral vector gene-transfer techniques and laser light) with neural imaging analyses (e.g., immunohistochemical assessment of anatomical patterns of genomic activation in limbic brain systems), and sensitive psychological analyses of behavior related to ‘wanting’ and ‘liking’ (e.g., Pavlovian sign-tracking and goal-tracking; optogenetic brain self-stimulation; operant conditioning; preference conditioning; taste reactivity; etc.). Our goal is to better understand how brain systems generate intense levels of motivation relevant to normal intense appetites and to pathological cases of eating disorders and obesity and of drug addiction and gambling.
A major focus is to understand when and how reward-associated cues become potent triggers that elicit craving, relapse and consumption, especially striking in cases of addiction and eating disorders. Reward cues are a chief cause of addictive relapse, yet the same cues can be motivationally impotent at other times. The key lies in the response to cues of brain mesocorticolimbic systems of incentive motivation, and the response of those brain systems can vary across time. Current work uses optogenetic stimulation techniques to elevate mesocorticolimbic reactivity in ways that amplify the motivational impact of reward cues, making the cues more attractive. Other recent work has used natural physiological appetites and natural junk-food induction of obesity to intensify the incentive salience of relevant reward cues via natural stimulation of mesocorticolimbic systems. These findings together provide insights towards treating disorders such as drug addiction, gambling, and eating disorders including obesity. In the sections below, I discuss some of my main recent findings and future directions.