Postoperative performance under an FR-1 schedule for delayed reinforcement Data plotted to show the effects of delays. All groups discriminated between the active and the inactive lever, and delays retarded acquisition of the active lever response in both groups. Postoperatively, shams' performance was unaltered, as was that of AcbC-lesioned rats in the 0 s delay condition. However, active lever responding was impaired postoperatively in AcbC-lesioned rats in the 10 s and 20 s conditions. (a) Responding of sham-operated control rats, under all three response-reinforcer delay conditions. The vertical black line indicates the time of surgery, between testing sessions 14 and 15. (b) Responding of AcbC-lesioned rats under all delay conditions. The next figure replots these data to show the effect of the lesion more clearly.