Imaging genetics for utility of risks over gains and losses.

One tenet of behavioral economics is the asymmetry in how decision makers evaluate risks involving gains versus risks involving losses. Correspondingly, an increasingly important question is what neuroanatomical and neurochemical correlates underpin valuation over gains and losses. By employing an imaging genetics strategy, this paper aims at identifying the specific neurotransmitter pathways underlying these decision making processes. We find enhanced striatal activation responding to increases in the magnitude of utility for risks over gains and to increases in the magnitude of disutility for risks over losses, while increased amygdala activation correlates only with the disutility for risks over losses. Stratifying brain activation by genotype, we find that a well-characterized polymorphism in the dopamine transporter (DAT1) contributes to individual differences in striatal response for gain-oriented risks, whereas a polymorphism in the serotonin transporter (STin2) partially accounts for individual differences in amygdala responses for loss-oriented risks. Together, our results suggest the role of the amygdala and corresponding serotonergic pathway in evaluating losses. This further corroborates the hypothesis of serotonin being linked to dopamine in an "opponent partnership".