Comparison of the effects of frontal, striatal, and septal lesions in paradigms thought to measure incentive motivation or behavioral inhibition

Bilateral electrolytic lesions of the ventral, but not dorsal, anterior striatum produced over-responding in rats performing on a modified DRL-30 sec schedule of reinforcement. This effect appears similar to that previously seen in rats with septal lesions but an analysis of the types of errors indicated important differences between the effects of septal and striatal lesions. Comparisons of rats with frontal, striatal and septal lesions with respect to their acquisition of saccharine licking, latency to eat in a novel environment, and acquisition of a runway response indicated that only septal lesions reliably enhance approach tendencies in these tests. The data suggest that the behavioral changes seen after striatal or frontal damage in the rat are not due to enhanced responsivity to rewarding stimuli.