The Specific Role of Dopamine in the Striatum during Operant Learning

Abstract

The role of dopamine in behavior is in a state of permanent controversy. The notion of ‘prediction error’ is a central component in current reward-based models of learning, but there are many caveats and contradictions in the supporting data. In this paper we propose that the same dopamine signal can both promote an action and reinforce it and we outline a novel model of reward-based learning in which dopamine operates as a teaching signal with DA release starting well before and persisting beyond the action being reinforced. The post-response signal providing the true excitatory drive for long-term potentiation (LTP) comes from the intralaminar nuclei of the thalamus. The main component of this hypothetical mechanism is the direct striatal projection neuron pathway, while there are indications that the indirect pathway is fundamentally able to modulate the direct pathway, thus providing behavioral flexibility.