The basal ganglia (BG) are essential for learning and adapting movements, yet their output is often unnecessary for executing well-learned actions. This paradox challenges existing models of BG function. I will present a biologically grounded model of the cortico-BG-thalamocortical loop, showing how this closed-loop network supports efficient motor adaptation and early movement acquisition. In our model, dopamine-driven plasticity, recurrent cortical dynamics, and feedback from the BG together shape motor output, even when BG output is not directly required for execution. This work provides a unified framework explaining how the BG-cortical circuit contributes to both learning and refinement of goal-directed actions. One important assumption of the model if that parallel feedback loops in the BG-cortical circuits form functional channels driving specific motor output, and I will show recent analysis of neuronal activity in the song-related circuit of zebra finch supporting this assumption.