Abstract
Timed dopamine signals underlie reinforcement learning, favoring neural activity patterns that drive behaviors with positive outcomes. In the striatum, dopamine activates five dopamine receptors (D1R-D5R), which are differentially expressed in striatal neurons. However, the role of specific dopamine receptors in reinforcement is poorly understood. Using our cell-specific D1R photo-agonist, we find that D1R activation in D1-expressing neurons in the dorsomedial striatum is sufficient to reinforce preceding neural firing patterns in defined ensembles of layer 5 cortico-striatal neurons of the mouse motor cortex. The reinforcement is cumulative and time dependent, with an optimal effect when D1R activation follows the selected neural pattern after a short interval. Our results show that D1R activation in striatal neurons can selectively reinforce cortical activity patterns, independent of a behavioral outcome or a reward, crucially contributing to the fundamental mechanisms that support cognitive functions like learning, memory, and decision-making.
Keywords:
D1R; cortico-striatal-thalamocortical loop; dopamine; learning; motor cortex; neuroprosthetic learning; reinforcement; striatum.