Prefrontal cortex lesions attenuate substantia nigra self-stimulation: a reward summation analysis.

A curve-shift paradigm was used to assess the effects of lesions of the prefrontal cortex on self-stimulation from electrode sites in the substantia nigra. Combined lesions of the medial and sulcal cortical regions severely attenuated substantia nigra self-stimulation. These results are discussed in the context of the frontal cortex and the substantia nigra as belonging to a reinforcement system that is largely independent of the medial forebrain bundle system.