Neurotoxic lesions of ventrolateral but not anteromedial neostriatum in rats impair differential reinforcement of low rates (DRL) performance.

In two separate experiments, rats received either kainic acid (KA), 6-hydroxydopamine (6-OHDA) or control lesions bilaterally into either the anteromedial or ventrolateral neostriatum. Both ventrolateral neurotoxic lesions disrupted post-operative body weight regulation and the acquisition of a DRL-20 sec operant schedule of reinforcement. The pattern of operant responding suggested that these animals had an impairment in response sequencing or switching. Rats with anteromedial lesions manifested neither body-weight nor DRL impairments.