Mean center entries (± SEM) displayed by male and female rats in round and square chambers on Baseline (left), ND1 (middle), and ND21 (right). **Male and female rats in square chambers (MS and FS) display lower levels of center entry than those in round chambers [F(1,78) = 35.124, p ≤ 0.001]. *Animals in round chambers (MR and FR) exhibit a sex difference with the MR group entering the center of the chamber more often than the FR group [F(1,78) = 4.817, p ≤ 0.031]. Note: unadjusted data from ND1 and ND21 were not analyzed using ANOVA due to sex differences at baseline. Thus, no asterisks are provided in the middle and right panels.