This week we have Guillaume Sescousse from the Donders Institute for Brain, Cognition and Behaviour at Radboud University (Nijmegen, Netherlands) visiting us and giving a talk in the Social, Economic, and Decision Psychology colloquium (Thursday,  May 19, 2016, 13:00, title and abstract follow).

Exploring the links between reward, dopamine and gambling addiction

Despite the pervasive hypothesis that reward sensitivity, dopamine, and gambling addiction are intimately related, the specific nature and direction of these links remain elusive. In this talk I will present a series of recent experiments tackling this question, using a combination of psychopharmacology, neurochemical PET and fMRI in humans. I will show that dopaminergic drugs modulate the relative sensitivity to reward vs punishment, but in opposite directions in healthy participants and gambling addicts. I will provide suggestive evidence that this individual variability in drug effects is related to an underlying variability in baseline dopamine synthesis capacity, which is enhanced in gambling addicts. I will also show that in the context of risky decision-making, dopamine modulates the subjective distortion of winning probabilities. Finally, I will present evidence showing that gambling addicts might not suffer from enhanced brain responses to winning, but to nearly winning (so-called ‘near-misses’). Together, these results shed light on the role of dopamine in reward sensitivity and gambling addiction. They also reinforce the baseline-dependency principle of dopaminergic drug effects, thus demonstrating the importance of a dimensional as opposed to a categorical approach to dopaminergic treatment in psychiatry.