Fig. 2. Rats were allowed to survive for 3 months after 10 min of severe forebrain ischemia while anesthetized with fentanyl–nitrous oxide or isoflurane. Concurrent sham-operated animals were not subjected to ischemia. On days 86 –90 after ischemia (or sham surgery), place-set Morris water maze performance was assessed. Although performance improved over the 5-day training intervals in all groups (P <0.001), there were no differences among groups (P = 0.29). Values are presented as mean ± SD.