Figure 2.

(A) Infusions earned on the first day of initial reduction (open symbols) and the average infusions earned over the last three sessions of Reduction 1 (closed symbols) for each group. Baseline infusions earned are shown for all rats at training dose (60 µg/kg/infusion). All groups have at least nine rats. (B) Infusions earned on the first day of each reduction (open symbols) and the average earned infusions over the last three sessions at each dose (closed symbols) for the gradual reduction group. Group size for the gradual reduction group is 15 rats at 60 and 30 µg/kg/infusion, 13 rats at 15, 7.5, and 3.75 µg/kg/infusion, and 12 rats at 1.875 µg/kg/infusion. Error bars are standard error of the mean in both graphs. Significant change from baseline is denoted by *. Significant change from first day to stable behavior is denoted by **. All ps < 0.05. Data from the 30 µg/kg/infusion dose are the same in both (A) and (B).