Topic: medium spiny neurons

I will discuss work with Jack Lindsey modeling reinforcement learning for action selection in the basal ganglia. I will argue that the presence of multiple brain regions, in addition to the basal ganglia, that contribute to motor control motivates the need for an off-policy basal ganglia learning algorithm. I will then describe a biological implementation of such an algorithm that predicts tuning of dopamine neurons to a quantity we call "action surprise," in addition to reward prediction error. In the same model, an implementation of learning from a motor efference copy also predicts a novel

Arginase 2 (Arg2), an arginine-metabolizing, mitochondrial enzyme, has been recently found to be enriched in the striatum, and progressive loss of Arg2 has been proposed as a potential factor contributing to the pathogenesis of Huntington’s disease (HD), a disorder primarily involving this region of the brain. Although direct metabolic role of Arg2 is well established, the importance of this enzyme for striatal function and dysfunction is not known. The purpose of this work was to identify cellular pathways potentially controlled by Arg2 in the striatum. In our experiments, we have used wild-t