Timeline of chronic subcutaneous THC injection and voluntary alcohol drinking. (A) In Experiment 1a (EtOH, n = 8; CTL, THC, & COM, n = 10/group), 3 mg/kg/day THC lasted for 8 days, while the 5 and 10 mg/kg/day THC each lasted for 4 days. Sucrose preference (SP) and Barnes maze (BM) tests were performed as indicated. (B) In Experiment 1b (n = 10/group), the four THC doses (3, 5, 10, & 20 mg/kg/day) each spanned 4 days. BM & SP tests were performed as indicated. Spatial learning (BML) occurred during the last 8 days of drug treatment.