Fig. 2.

Effects of M100907 on cocaine self-administration, expressed as the mean ± SEM number of reinforcers (infusions of cocaine with cues) received over a 1-h test session in each dosage group (a) and collapsed across dosage groups (b). Animals assigned to receive 0.1 (n=6), 0.3 (n= 6), 1.0 (n=6), or 1.5 (n=5) μg/0.2 μl/side M100907 into the vmPFC were tested on 1 day with their assigned dose (striped bar) and on another day with the vehicle (black bar), with order counterbalanced. Baselines (white bar) were calculated as the average number of reinforcers obtained during the first hour of the self-administration sessions immediately preceding each test. There was a small, but significant decrease in responding on the M100907 test day relative to baseline when collapsed across dose (i.e., main effect of test day). The asterisk (*) represents a significant difference from extinction baseline, test of simple main effects, P<0.05