title: Human Choice Strategy Varies with Anatomical Projections from Ventromedial Prefrontal Cortex to Medial Striatum.
abstract: Two distinct systems, goal-directed and habitual, support decision making. It has recently been hypothesized that this distinction may arise from two computational mechanisms, model-based and model-free reinforcement learning, neuronally implemented in frontostriatal circuits involved in learning and behavioral control. Here, we test whether the relative strength of anatomical connectivity within frontostriatal circuits accounts for variation in human individuals' reliance on model-based and model-free control. This hypothesis was tested by combining diffusion tensor imaging with a multistep decision task known to distinguish model-based and model-free control in humans. We found large interindividual differences in the degree of model-based control, and those differences are predicted by the structural integrity of white-matter tracts from the ventromedial prefrontal cortex to the medial striatum. Furthermore, an analysis based on masking out of bottom-up tracts suggests that this effect is driven by top-down influences from ventromedial prefrontal cortex to medial striatum. Our findings indicate that individuals with stronger afferences from the ventromedial prefrontal cortex to the medial striatum are more likely to rely on a model-based strategy to control their instrumental actions. These findings suggest a mechanism for instrumental action control through which medial striatum determines, at least partly, the relative contribution of model-based and model-free systems during decision-making according to top-down model-based information from the ventromedial prefrontal cortex. These findings have important implications for understanding the neural circuitry that might be susceptible to pathological computational processes in impulsive/compulsive psychiatric disorders.
authors.affiliation: Donders Institute for Brain, Cognition, and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands p.piray@donders.ru.nl.
authors.forename: Payam
authors.identifier: http://orcid.org/0000-0002-8100-6628
authors.initials: P
authors.lastname: Piray
authors.affiliation: Donders Institute for Brain, Cognition, and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands.
authors.forename: Ivan
authors.identifier: http://orcid.org/0000-0003-0936-3601
authors.initials: I
authors.lastname: Toni
authors.affiliation: Donders Institute for Brain, Cognition, and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands.
authors.forename: Roshan
authors.initials: R
authors.lastname: Cools
mesh_terms: D000328:Adult; D001499:Bayes Theorem; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology*; D003198:Computer Simulation; D003342:Corpus Striatum / Q000033:anatomy & histology* / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016015:Logistic Models; D008297:Male; D008960:Models, Psychological; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D010812:Physical Stimulation; D017397:Prefrontal Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D055815:Young Adult
keywords: connectivity; decision making; diffusion tensor imaging; reinforcement learning; striatum; ventromedial prefrontal cortex