Models of Dopamine-Modulated Corticostriatal Plasticity

The corticostriatal synapses are a major site of neural plasticity in the brain. They form the primary input to the basal ganglia as part of the broader cortico-basal ganglia-thalamic loop, a circuit that plays an important role in action selection. Corticostriatal plasticity is modulated by the neurotransmitter dopamine, which is believed to signal a reward prediction error that allows the brain to perform reinforcement learning, strengthening pathways corresponding to rewarding actions and weakening the pathways for actions that do not lead to reward. In this talk I will discuss three models of corticostriatal plasticity incorporating both spike-timing-dependent plasticity and dopaminergic modulation. I examine several different tasks that we believe are representative of the kinds of tasks this plasticity mechanism likely performs in the brain. While each plasticity model performs well on some tasks, none are able to accomplish all of them, suggesting that our models of corticostriatal plasticity are currently incomplete.