 Reinforcement learning algorithms such as TD learning are under investigation as a model for dopamine-based learning in the brain.In this model, the dopaminergic projections from the substantia nigra to the basal ganglia function as the prediction error.Reinforcement learning has been used as a part of the model for human skill learning, especially in relation to the interaction between implicit and explicit learning in skill acquisition (the first publication on this application was in 1995–1996).