title: The Dopaminergic Midbrain Encodes the Expected Certainty about Desired Outcomes.
abstract: Dopamine plays a key role in learning; however, its exact function in decision making and choice remains unclear. Recently, we proposed a generic model based on active (Bayesian) inference wherein dopamine encodes the precision of beliefs about optimal policies. Put simply, dopamine discharges reflect the confidence that a chosen policy will lead to desired outcomes. We designed a novel task to test this hypothesis, where subjects played a "limited offer" game in a functional magnetic resonance imaging experiment. Subjects had to decide how long to wait for a high offer before accepting a low offer, with the risk of losing everything if they waited too long. Bayesian model comparison showed that behavior strongly supported active inference, based on surprise minimization, over classical utility maximization schemes. Furthermore, midbrain activity, encompassing dopamine projection neurons, was accurately predicted by trial-by-trial variations in model-based estimates of precision. Our findings demonstrate that human subjects infer both optimal policies and the precision of those inferences, and thus support the notion that humans perform hierarchical probabilistic Bayesian inference. In other words, subjects have to infer both what they should do as well as how confident they are in their choices, where confidence may be encoded by dopaminergic firing.
authors: The Wellcome Trust Centre for Neuroimaging, UCL, London WC1N 3BG, UK Centre for Neurocognitive Research and Department of Psychology, University of Salzburg, Salzburg, Austria Neuroscience Institute and Centre for Neurocognitive Research, Christian-Doppler-Klinik, Paracelsus Medical University Salzburg, Salzburg, Austria.
authors: Philipp
authors: P
authors: Schwartenbeck
authors: The Wellcome Trust Centre for Neuroimaging, UCL, London WC1N 3BG, UK.
authors: Thomas H B
authors: TH
authors: FitzGerald
authors: The Wellcome Trust Centre for Neuroimaging, UCL, London WC1N 3BG, UK Max Planck UCL Centre for Computational Psychiatry and Ageing Research, London, UK.
authors: Christoph
authors: C
authors: Mathys
authors: The Wellcome Trust Centre for Neuroimaging, UCL, London WC1N 3BG, UK.
authors: Ray
authors: R
authors: Dolan
authors: The Wellcome Trust Centre for Neuroimaging, UCL, London WC1N 3BG, UK.
authors: Karl
authors: K
authors: Friston
mesh_terms: D000328:Adult; D001499:Bayes Theorem; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology; D002755:Choice Behavior / Q000502:physiology*; D003220:Conflict, Psychological; D004298:Dopamine / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012306:Risk; D013378:Substantia Nigra / Q000502:physiology*; D017557:Ventral Tegmental Area / Q000502:physiology*; D055815:Young Adult
chemical_list: D004298:Dopamine
keywords: active inference; confidence; dopamine; neuroeconomics; precision