Fig. 1.

Food-maintained behavior after i.g. MDMA (0.32–7.8 mg/kg) or vehicle administration in four baboons during the daily 20-hour period of food pellet availability. The solid line presents the mean (± S.D.) cumulative total of 1 g food pellets earned from 15 minutes to 20 hours after vehicle was infused in control sessions (n = 5 for GD, n = 6 for PY and YO, and n = 4 for SHA). Open and closed symbols present the cumulative total food pellets earned from 15 minutes to 20 hours after the MDMA dose was infused. Note difference in the scale of y-axis in panels on the left compared with those on the right. MDMA doses were studied once in each baboon (see Table 1 for dose order; note that 0.32 was not studied in SHA and 7.8 mg/kg was not studied in GD and SHA). For GD, unprogrammed restricted access to pellets (i.e., feeder malfunction) on the day preceding 3.2 mg/kg MDMA preclude including data for this dose. *Indicates the total number of food pellets earned over the 20-hour period was significantly lower compared with vehicle (value fell outside the 95% confidence limits of the calculated z-scores for vehicle).