DRL performance following ventromedial hypothalamic lesions in rats

Obese ventromedial hypothalamic lesioned rats obtained more reinforcers than control or lean VMH animals when switched from a continuous reinforcement schedule to a differential-reinforcement-of-low-rate (DRL) operant schedule for food reinforcement. There was no significant difference among the three groups in the number of responses emitted on the DRL schedule. An examination of interresponse times revealed that both lean and obese VMH animals suppressed post-reinforcement short-latency responding earlier than control animals. The results do not support the hypothesis that VMH lesions cause a general deficit in response inhibition.