Alcohol dependence has repeatedly been associated with impulsive choice, or the inability to choose large delayed rewards over smaller, but more immediate rewards. However, the neural basis of impulsive choice in alcohol use disorders is not well understood.
One hundred fifty one individuals with a range of alcohol use from social drinking to severe alcohol dependence completed a delay discounting task while undergoing functional magnetic resonance imaging (fMRI). Participants received customized trials designed to ensure an approximately equivalent number of immediate responses.
Delaying gratification recruited regions involved in cognitive control, conflict monitoring, and the interpretation of somatic states. Individuals with more severe alcohol use problems showed increased discounting of delayed rewards and greater activation in several regions including supplementary motor area, insula/orbitofrontal cortex, inferior frontal gyrus, and the precuneus.
These results suggest that impulsive choice in alcohol dependence is the result of functional anomolies in widely distributed, but interconnected brain regions involved in cognitive and emotional control. Further, our results suggest that the neural mechanisms of impulsive choice in alcohol use disorders both overlaps with that observed in previous studies, and shows that individuals with alcohol use disorders recruit additional mechanisms when making intertemporal choices.