title: Dopamine, time, and impulsivity in humans.
abstract: Disordered dopamine neurotransmission is implicated in mediating impulsiveness across a range of behaviors and disorders including addiction, compulsive gambling, attention-deficit/hyperactivity disorder, and dopamine dysregulation syndrome. Whereas existing theories of dopamine function highlight mechanisms based on aberrant reward learning or behavioral disinhibition, they do not offer an adequate account of the pathological hypersensitivity to temporal delay that forms a crucial behavioral phenotype seen in these disorders. Here we provide evidence that a role for dopamine in controlling the relationship between the timing of future rewards and their subjective value can bridge this explanatory gap. Using an intertemporal choice task, we demonstrate that pharmacologically enhancing dopamine activity increases impulsivity by enhancing the diminutive influence of increasing delay on reward value (temporal discounting) and its corresponding neural representation in the striatum. This leads to a state of excessive discounting of temporally distant, relative to sooner, rewards. Thus our findings reveal a novel mechanism by which dopamine influences human decision-making that can account for behavioral aberrations associated with a hyperfunctioning dopamine system.
authors.affiliation: Wellcome Trust Centre for Neuroimaging, London WC1N 3BG, United Kingdom. a.pine@ucl.ac.uk
authors.forename: Alex
authors.initials: A
authors.lastname: Pine
authors.forename: Tamara
authors.initials: T
authors.lastname: Shiner
authors.forename: Ben
authors.initials: B
authors.lastname: Seymour
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Dolan
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D001931:Brain Mapping; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology; D003657:Decision Making / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D007175:Impulsive Behavior / Q000175:diagnosis / Q000503:physiopathology*; D007980:Levodopa / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D008297:Male; D012055:Reinforcement Schedule; D012201:Reward; D013997:Time Factors; D055815:Young Adult
chemical_list: D015259:Dopamine Agents; D018492:Dopamine Antagonists; D007980:Levodopa; D006220:Haloperidol; D004298:Dopamine