title: Sensitivity of the nucleus accumbens to violations in expectation of reward.
abstract: This study examined whether ventral frontostriatal regions differentially code expected and unexpected reward outcomes. We parametrically manipulated the probability of reward and examined the neural response to reward and nonreward for each probability condition in the ventral striatum and the orbitofrontal cortex (OFC). By late trials of the experiment, subjects showed slower behavioral responses for the condition with the lowest probability of reward, relative to the condition with the highest probability of reward. At the neural level, both the nucleus accumbens (NAcc) and OFC showed greater activation to rewarded relative to nonrewarded trials, but the accumbens appeared to be most sensitive to violations in expected reward outcomes. These data suggest distinct roles for frontostriatal circuitry in reward prediction and in responding to violations in expectations.
authors.affiliation: The Sackler Institute for Developmental Psychobiology, Weill Cornell Medical College of Cornell University, 1300 York Avenue, Box 140, New York, NY 10021, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Spicer
authors.forename: Adriana
authors.initials: A
authors.lastname: Galvan
authors.forename: Todd A
authors.initials: TA
authors.lastname: Hare
authors.forename: Henning
authors.initials: H
authors.lastname: Voss
authors.forename: Gary
authors.initials: G
authors.lastname: Glover
authors.forename: Bj
authors.initials: B
authors.lastname: Casey
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009714:Nucleus Accumbens / Q000502:physiology*; D012201:Reward