Figure 1.

Methamphetamine and saline self-administration training. Data are the mean ± SEM number of methamphetamine (0.1 mg/kg/infusion) or saline infusions during the 10 9 h daily self-administration sessions for Experiment 1 (A: total, n = 23), Experiment 2 (B: total, n = 25), and Experiment 3 (C: total, n = 65). During training, active lever presses were reinforced on an FR1 20 s time-out reinforcement schedule, and methamphetamine or saline infusions were paired with a 5 s tone/light cue.