Mean number of Fos-positive nuclei/mm2 (±SEM) in the orbital (A), primary motor (B), infralimbic (C) and prelimbic (D) cortex regions of rats following challenge injections under isoflurane (ISO groups, shaded) or no anesthesia (NoA groups, white). Rats received repeated daily treatments across 7 days of either cocaine (C; 2 mg/kg, i.v.) or saline (S), followed by a challenge injection of C or S, with group names representing these sequential treatments. * p < 0.05 different from CC-ISO (Newman-Keuls). + p < 0.05 different from SS-NoA. Group sizes are SC-NoA: n=6, CC-NoA: n=9, CC-ISO: n=5, SS-NoA: n=5, SS-ISO: n=6.