Distinct dopaminergic spike-timing-dependent plasticity rules are suited to different functional roles.

Learning from feedback is a crucial ability that allows humans and other animals to respond and adapt to their environments. One important locus for such learning is the basal ganglia, where dopamine-modulated corticostriatal plasticity shapes the dynamics of the cortico-basal ganglia-thalamic network in response to feedback signals to promote adaptive behavior. In this paper we ask, what learning rule is best suited to modeling this dopamine-modulated plasticity? To that end we investigate three learning rules that incorporate spike-timing-dependent plasticity as well as dopaminergic modulation. We study their performance in several settings meant to model the kinds of tasks and scenarios that striatal neurons are likely to be involved in. Each plasticity rule we examined performs well in some settings but fails in others. Different plasticity mechanisms may therefore be better suited to different functional roles and potentially to different regions of the brain.