AUTHOR=Fiore Vincenzo G., Sperati Valerio , Mannella Francesco , Mirolli Marco , Gurney Kevin , Friston Karl , Dolan Raymond J., Baldassarre Gianluca TITLE=Keep focussing: striatal dopamine multiple functions resolved in a single mechanism tested in a simulated humanoid robot JOURNAL=Frontiers in Psychology VOLUME=5 YEAR=2014 URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2014.00124 DOI=10.3389/fpsyg.2014.00124 ISSN=1664-1078 ABSTRACT=

The effects of striatal dopamine (DA) on behavior have been widely investigated over the past decades, with “phasic” burst firings considered as the key expression of a reward prediction error responsible for reinforcement learning. Less well studied is “tonic” DA, where putative functions include the idea that it is a regulator of vigor, incentive salience, disposition to exert an effort and a modulator of approach strategies. We present a model combining tonic and phasic DA to show how different outflows triggered by either intrinsically or extrinsically motivating stimuli dynamically affect the basal ganglia by impacting on a selection process this system performs on its cortical input. The model, which has been tested on the simulated humanoid robot iCub interacting with a mechatronic board, shows the putative functions ascribed to DA emerging from the combination of a standard computational mechanism coupled to a differential sensitivity to the presence of DA across the striatum.