Fig. 2

Effects of different dosages of MK-801, haloperidol, and SCH23390 on the percentage of foraged standard food pellets (a–c), amount of foraged food (d–f), and amount of eaten food (g–i) under Condition 2. a There are no differences in the ratio of foraged standard food pellets from the cage with or without a residing rat after administration of 0.1, 0.15, or 0.2 mg/kg MK-801; b–c. the percentage of foraged standard food pellets from the rat-residing cage in vehicle, haloperidol, and SCH23390 treatment groups were significantly increased compared with the no-rat cage. *p<0.05, **p<0.01, ***p<0.001 represent statistically significant differences compared to foraged standard food pellets from the no-rat cage; d–f. The total amount of foraged food decreased with increasing dosages of MK-801, haloperidol, and SCH 23390 treatment. d *p<0.05 vs veh group, ##p<0.01 vs veh, 0.05 mg/kg and 0.10 mg/kg group, $p<0.05 vs 0.15 mg/kg group; e *p<0.05 vs veh group, ##p<0.01 vs veh group, $p<0.05 vs 0.01 mg/kg group; f *p<0.05 vs veh group; g–i no obvious alterations of the amount of food eaten were observed after MK-801 or SCH 23390 treatment; The amount of food eaten decreased after 0.05 mg/kg haloperidol injection. **p<0.01 vs the other group