A midbrain-thalamus-cortex circuit reorganizes cortical dynamics to initiate movement.

Motor behaviors are often planned long before execution but only released after specific sensory events. Planning and execution are each associated with distinct patterns of motor cortex activity. Key questions are how these dynamic activity patterns are generated and how they relate to behavior. Here, we investigate the multi-regional neural circuits that link an auditory "Go cue" and the transition from planning to execution of directional licking. Ascending glutamatergic neurons in the midbrain reticular and pedunculopontine nuclei show short latency and phasic changes in spike rate that are selective for the Go cue. This signal is transmitted via the thalamus to the motor cortex, where it triggers a rapid reorganization of motor cortex state from planning-related activity to a motor command, which in turn drives appropriate movement. Our studies show how midbrain can control cortical dynamics via the thalamus for rapid and precise motor behavior. [Display omitted] • Distinct motor cortex activity patterns underlie planning and movement initiation • A contextual cue reorganizes motor cortex activity to initiate planned movements • Midbrain neurons transmit information to cortex via thalamus to release movements • Midbrain activity is causal for reorganizing cortical activity and releasing movements Ascending midbrain neurons trigger rapid reorganization of motor cortex activity via thalamus to switch from planning-related activity to a motor command that initiates movement in mice [ABSTRACT FROM AUTHOR]