Specific role of dopamine in striatum during instrumental learning.

Research of dopamine's role in behavior is seemingly in a state of permanent controversy over all major topics. The notion of 'prediction error' is a central component of current reward leaning models, but there are many caveats and contradictions in supporting data. In this paper we propose that the same dopamine signal can promote action and reinforce this action, and outline novel model of reward learning in which dopamine provides a kind of teaching signal with DA release starting well before and persisting beyond the to-be reinforced action. The post-response signal that provides the true excitatory drive for LTP comes from intralaminar thalamus. The main part of hypothesized mechanism constitutes the direct pathway of striatal projection neurons and there are reasons to believe that the indirect pathway has the essential possibility to modulate the direct pathway, thus providing behavioral flexibility.