title: Time representation in reinforcement learning models of the basal ganglia.
abstract: Reinforcement learning (RL) models have been influential in understanding many aspects of basal ganglia function, from reward prediction to action selection. Time plays an important role in these models, but there is still no theoretical consensus about what kind of time representation is used by the basal ganglia. We review several theoretical accounts and their supporting evidence. We then discuss the relationship between RL models and the timing mechanisms that have been attributed to the basal ganglia. We hypothesize that a single computational system may underlie both RL and interval timing-the perception of duration in the range of seconds to hours. This hypothesis, which extends earlier models by incorporating a time-sensitive action selection mechanism, may have important implications for understanding disorders like Parkinson's disease in which both decision making and timing are impaired.
authors.affiliation: Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology Cambridge, MA, USA.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Gershman
authors.affiliation: School of Social Sciences and Psychology, Marcs Institute for Brain and Behaviour, University of Western Sydney Sydney, NSW, Australia.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Moustafa
authors.affiliation: Princeton Neuroscience Institute and Department of Mechanical and Aerospace Engineering, Princeton University Princeton, NJ, USA ; Department of Psychology, University of Warwick Coventry, UK.
authors.forename: Elliot A
authors.initials: EA
authors.lastname: Ludvig
keywords: Parkinson's disease; basal ganglia; dopamine; interval timing; reinforcement learning