Involvement of the rat prefrontal cortex in a delayed reinforcement operant task

To determine whether the rat medial prefrontal cortex (PFC) is involved in delayed reinforcement operant behavior, we studied the effects of transient inactivation of the medial PFC (or the hippocampus as a control) during a delayed reinforcement lever-press task. We demonstrated the involvement of the PFC in this task: PFC inactivation but not hippocampal inactivation significantly impaired performance. In a separate experiment, we also recorded the prefrontal multiple unit activities during the task to determine the roles of the PFC in detail. Neuronal activity decreased during the delay period, suggesting that this decrease plays a role in delayed reinforcement operant behavior. (C) 2007 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.