PSD-95 KO show long-term loss of EtOH conditioned place preference. (a) Schematic of study design. (b) WT and KO showed significant preference for the EtOH-paired compartment 1 day after conditioning. When tested 14 days after conditioning, WT retained a significant preference for the EtOH-paired side while KO showed a significant aversion to the EtOH-paired side. (c) Both genotypes preferred the EtOH-paired side, as measured by cumulative time spent in that compartment, 1 day after conditioning. (d) WT preference for the EtOH-paired side was intact 14 days post-conditioning, while KO showed an increasing aversion to the EtOH-paired side, as measured by cumulative time spent in the EtOH-paired side (n = 10/genotype). Data are Means ± SEM. #P < 0.05 versus 50% chance/same genotype, **P < 0.01 versus WT/same test day