The Number of active (drug-paired) lever presses, and cocaine infusions across cocaine self-administration sessions in ShA (a), first 2 hr of LgA (b), and the entire 6 hr sessions of LgA groups (c). The number of active lever presses (d), cocaine infusions (e), and amount of cocaine intake (mg/kg, f) during the first and the last day of ShA, first 2 hr of LgA, and the entire LgA 6-hr sessions. Significant differences between the first and last day within each group are indicated (**p<0.01; N=6-9 per group).