From habits to actions: dorsolateral striatum lesions alter the content of learning

Actions are controlled by the expectation of an outcome, whereas habits are elicited by the prevailing stimuli, autonomous of the outcome. In this study, the dorsolateral striatum is shown to be necessary for the formation of a habit. Rats were trained to press a lever under interval schedules, which generated habitual responses in sham operated controls. These rats showed similar response rates whether or not the outcome had been independently made aversive to them In contrast, although rats with dorsolateral striatal lesions acquired the instrumental response, they refrained from responding almost completely after the goal had been devalued. Thus, damage to the dorsolateral striatum prevented habit formation, resulting in goal-directed behavior under conditions which generated habits in normal animals.