Cortical lesions interfere with behavioral recovery from unilateral substantia nigra lesions induced by brain grafts

Effects of aspiration lesions of the cerebral cortex on the behavioral effects of intraventricular substantia nigra grafts were investigated. Apomorphine-induced rotational behavior consequent to unilateral lesions of the substantia nigra was used as a behavioral measure. Substantia nigra grafts reduced rotational behavior in animals with sham cortical lesions. Cortical lesions also decreased rotational behavior and, in these animals, no additional decrease in rotational behavior was induced by substantia nigra grafts. It is concluded that cortical lesions alter striatal circuitry so as to preclude a behavioral effect of substantia nigra grafts.