(a) Viral vectors expressing Cre Recombinase were delivered to the PL of ‘floxed’ Bdnf mice, generating a site-selective knockdown. Control mice received a viral vector expressing Green Fluorescent Protein (GFP). The largest viral vector spread is represented in gray, the smallest in black. (b) Bdnf knockdown caused a persistent drop in responding for food reinforcers on a progressive ratio schedule of reinforcement; meanwhile, knockdown increases cocaine-reinforced responding on a progressive ratio schedule (Sadri-Vakili et al., 2010). (c) We re-analyzed data from typical mice or mice chronically exposed to the stress hormone corticosterone in Gourley et al. (2012a), generating groups based on a median split of endogenous PL BDNF levels. Corticosterone reduced BDNF overall. Additionally, “high” BDNF was associated with high break point ratios, while “low” BDNF was associated with low break point ratios, again pointing to differential roles for mPFC BDNF in regulating food- vs. cocaine-reinforced responding on a progressive ratio schedule (cf., Sadri-Vakili et al., 2010). Figure components are compiled or reprinted from Gourley et al., 2012a. Bars and symbols represent group means+SEMs, *p<0.05.