Behavioral analysis of experimental (vehicle-treated) and CPP-treated rats in a multicompartment environment. A, Numbers of movements (30 min session, 5 min bins) on day 1 did not differ between CPP and experimental (EXP) rats; these groups exhibited comparable decreases in activity over the test session (***p = 0.0004, **p = 0.002, *p = 0.05 vs 30 min of the EXP group; +++p = 0.0001, ++p = 0.008 vs 30 min of the CPP group). B, Numbers of movements for the first 20 min of testing on day 1 versus the same period on day 2. The mean number of events decreased on day 2 in EXP but not CPP-treated rats (**p = 0.02). C, Mean duration of visits to the object area during the first 20 min of testing on days 1 and 2. This value, which was not correlated with numbers of movements (r = 0.26), decreased between the 2 d for EXP but not CPP rats (***p < 0.001). D, Total time visiting the objects during days 1 and 2. This measure, which combines number and mean duration of visits, decreased for EXP but not for CPP rats (***p = 0.001).