All methods used were in compliance with National Institutes of Health guidelines for care of laboratory animals and were approved by the Medical University of South Carolina or the University of Iowa Internal Animal Care and Use Committee. Male Sprague-Dawley rats were single, housed with a 12-hour reverse light/dark cycle. Animals were anesthetized and virus (rAAV2-hSyn-eNpHR3.0-EYFP, rAAV5-hSyn-EYFP, rAAV2-CAG-ArchT-GFP or rAAV5-CMV-GFP in |1012 viral molecules in 0.7 μl, University of North Carolina Vector Core) was stereotaxically delivered into the PL or NAcore. Twelve daily self-administration sessions lasted 2 hours or until the rats had taken a maximum of 200 infusions. Cocaine was self-administered using a Fixed Ratio 1 schedule with a 20-second timeout. Active lever presses produced a 0.05-ml infusion of 200 μg of cocaine and a 5-second tone/light cue. Rats underwent 10 d of extinction and then underwent either a cocaine- (10 mg/kg, ip) or a cocaine + cue-induced reinstatement where lever presses had no consequences. Rats underwent two reinstatement sessions for one or both types of reinstatement, counterbalanced with respect to whether illumination was provided. Illumination (10 mW of
