Effects of 1,4-BD on duration to complete the fine-motor task across dosing conditions. Data shown are the mean (SEM) durations to complete the task (maximum of 120 sec) across daily presentations during 7 days of the vehicle (“VEH”) baseline, during the first 7 days of 400-600 mg/kg 1,4-BD, across 7 seven days during week 2 (400 mg/kg), week 3 (500 and 600 mg/kg), and week 4 (600 mg/kg) of chronic 1,4-BD, and during weeks 1 and 2 of the spontaneous withdrawal phase. a indicates significantly different from vehicle baseline, b indicates significantly different from the first week of chronic 400-600 mg/kg 1,4-BD dosing for that respective dose, and c indicates significantly different from week 4 of chronic 600 mg/kg 1,4-BD dosing (for spontaneous withdrawal comparisons only).