A Functional Taxonomy of Bottom-Up Sensory Feedback Processing for Motor Actions.

Humans are adept at performing an extraordinary breadth of voluntary motor actions that allow us to rapidly move around and interact with the environment. While voluntary motor actions necessarily include top-down intention to generate a motor act, a key to voluntary control is the selective use of bottom-up sensory feedback to select and guide motor actions. This review classifies the many ways in which sensory feedback is used by the motor system and highlights regularities in the timing of each class of motor responses to sensory stimuli, revealing a functional hierarchical organization of motor control. The highly automatic way in which feedback is typically used in goal-directed action blurs the distinction between reflexes and voluntary control.