Abstract
Despite clear evidence linking basal ganglia control to habits, it remains unclear through what mechanisms this control occurs. Here, we demonstrate that a key function of the dorsolateral striatum (DLS) is to regulate the vigor of a learned behavior at the moment of initiation in a habit-promoting manner. Shifts in vigor by phasic DLS perturbations coincide closely with how outcome-insensitive (i.e., habitual) the behaviors are in both response-based and cue-based task situations. Surprisingly, the control over habit strength by way of changes in vigor occurs without consistent changes in accuracy, suggesting that mechanisms controlling habit and vigor are dissociable from performance governed task rules. Finally, we show that increased DLS activity improves vigor preferentially when learned outcome values are stable, while reduced DLS activity dampens vigor preferentially when outcome values change. These data indicate that improving action vigor could be a principle route by which the basal ganglia facilitate habits.
Contributions
KSS and ACGC: designed research, analyzed data, wrote the paper; ACGC, FS, AGM, MVDM, and EC: Performed research.
Acknowledgements
We thank Kenneth Amaya, Jacqueline Perron-Smith, Elizabeth McNalley, Alyssa DiLeo, Alex Brown, and Dr. Stephen Chang for assistance. This work was supported by an NSF research grant to KSS (IOS 1557987).
Footnotes
Conflict of interest: The authors declare no competing financial interests.








