Effects of regional striatal lesions on motor, motivational, and executiveaspects of progressive-ratio performance in rats

The striatum is implicated in response selection and performance, the dorsa l striatum in sensorimotor control and habit learning, and the ventral stri atum in motivation and rewarded behaviors. Ventral striatal lesions produce performance changes on food-reinforced, progressive-ratio (PR) schedules, but the effects of dorsal striatal lesions on this task are not known. In t his study, neither medial nor lateral dorsal striatal lesions produced defi cits on the main motivational indices of PR performance. In contrast, signi ficant impairments were observed in motoric or "executive" aspects of perfo rmance. Motivationally related manipulations of the task (food deprivation and reward magnitude) produced some subtle lesion-specific changes in behav ior on these motoric or executive aspects of performance. Findings are disc ussed in relation to the roles of the dorsal and ventral striatum in reward -related behaviors.