The striatum multiplexes contextual and kinematic information to constrain motor habits execution

The authors recorded spiking activity in the sensorimotor striatum of rats performing a motor sequence in an automatic manner. They report continuous and integrative representation of contextual and kinematic information. Reversible perturbation of these representation increased execution variability, suggesting a strong contribution in constraining the execution motor habits. The striatum is required for the acquisition of procedural memories, but its contribution to motor control once learning has occurred is unclear. We created a task in which rats learned a difficult motor sequence characterized by fine-tuned changes in running speed adjusted to spatial and temporal constraints. After training and extensive practice, we found that the behavior was habitual, yet tetrode recordings in the dorsolateral striatum (DLS) revealed continuous integrative representations of running speed, position and time. These representations were weak in naive rats that were hand-guided to perform the same sequence and developed slowly after learning. Finally, DLS inactivation in well-trained animals preserved the structure of the sequence while increasing its trial-by-trial variability. We conclude that, after learning, the DLS continuously integrates task-relevant information to constrain the execution of motor habits. Our results provide a straightforward mechanism by which the basal ganglia may contribute to habit formation and motor control.