Imaging and lesion studies support the view that goal-oriented and routine behaviors are supported by different mechanisms. While the execution of routine behaviors can be achieved autonomously by posterior cortical networks, which include sensory and motor areas, the orchestration of complex goal-directed behaviors requires the interaction of prefrontal networks with the posterior system. These interactions are thought to be the neural signature of supervisory attention to action. It is believed that this interaction can serve as a scaffold for the formation of habits and skills. After extensive practice, learned behaviors become resistant to reward devaluation and can execute seamlessly without attentional supervision. Here I review candidate mechanisms at the network and cellular levels that can explain these phenomena.