title: Balancing reward and work: anticipatory brain activation in NAcc and VTA predict effort differentially.
abstract: Complex decision-making involves anticipation of future rewards to bias effort for obtaining it. Using fMRI, we investigated 50 participants employing an instrumental-motivation task that cued reinforcement levels before the onset of the motor-response phase. We extracted timecourses from regions of interest (ROI) in the mesocorticolimbic system and used a three-level hierarchical model to separate anticipatory brain responses predicting value and subsequent effort on a trial-by-trial basis. Whereas all ROIs scaled positively with value, higher effort was predicted by higher anticipatory activation in nucleus accumbens (NAcc) but lower activation in ventral tegmental area/substantia nigra (VTA/SN). Moreover, anticipatory activation in the dorsal striatum predicted average effort whereas higher activation in the amygdala predicted above-average effort. Thus, anticipatory activation entails the appetitive drive towards reinforcement that requires effort in order to be obtained. Our results support the role of NAcc as the main hub supported by the salience network operating on a trial-by-trial basis, while the dorsal striatum incorporates habitual responding.
authors.affiliation: Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Nils B
authors.initials: NB
authors.lastname: Kroemer
authors.affiliation: Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany; Escuela de Matemática Universidad de Costa Rica, San José, Costa Rica.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Guevara
authors.affiliation: Department of Mathematics, University of Oxford, Oxford, UK; Mathematical Institute, Leiden University, Leiden, Netherlands.
authors.forename: Iuliana
authors.initials: I
authors.lastname: Ciocanea Teodorescu
authors.affiliation: Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Wuttig
authors.affiliation: Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Kobiella
authors.affiliation: Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany. Electronic address: michael.smolka@tu-dresden.de.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Smolka
mesh_terms: D000328:Adult; D059031:Anticipation, Psychological / Q000502:physiology*; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D003463:Cues; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009042:Motivation / Q000502:physiology*; D009714:Nucleus Accumbens / Q000502:physiology*; D005082:Physical Exertion; D012201:Reward; D017557:Ventral Tegmental Area / Q000502:physiology*
keywords: Effort discounting; Instrumental motivation; Midbrain; Ventral striatum; fMRI