Unilateral stimulation of the dorsolateral striatum attenuates
goal-directed action.
Abstract
It has long been known that the dorsomedial (DMS) and dorsolateral
stratium (DLS) mediate distinct forms of action control with DMS
mediating goal-directed actions and DLS mediating habits. Recent
evidence suggests that, in accord with its role in goal-directed
control, unilateral stimulation of dorsomedial striatum (DMS) enhances
actions contralateral to the stimulation in a manner that scales with
the prior reward history of that action. In the current study we
assessed whether the effects of unilateral stimulation of the
dorsolateral striatum (DLS) induces a response bias that reflects
enhanced habitual control, as measured by the effect of stimulation on
on-going goal-directed control. Rats were first trained to press two
levers for distinct outcomes in a manner likely to induce goal-directed
control of these actions. We then assessed the effects of unilateral
hM3D DREADDs-induced stimulation of the DMS or DLS, applied during an
outcome devaluation choice test and outcome-mediated reinstatement, both
known to depend on DMS activity. DMS stimulation had no impact on choice
of either the action ipsilateral or contralateral to the stimulation
either during devaluation or reinstatement. In contrast, stimulation of
the DLS abolished goal-directed control in both tests, reducing
sensitivity to outcome devaluation both on the ipsilateral and
contralateral lever. In addition, stimulation both attenuated
reinstatement and induced a response bias away from the contralateral
lever during reinstated responding. These data suggest that the effects
of stimulation of the DLS are modulated by its role in habitual control.