Fig. 1.

UCMS protocol and physical, corticosterone regulation, and behavioral alterations. (A) Overview of the protocol. Mice were randomly assigned to the control (gray) or the UCMS (red) group. (B) Body weight, (C) coat state, (D) HPA axis negative feedback [dexamethasone (DEX) suppression test; DST; n = 5–7 per group], (E and F) self-centered behavior (grooming test; GT), (G) motivation (nest building test; NBT), and (H and I) locomotor activity, were measured at baseline and during the 9-wk UCMS. From day 43, several behavioral domains were evaluated, including (J and K) anhedonia-like (reward-driven exploratory test assessing the motivation to collect a palatable stimulus; latency and number of chews), (L) despair (depressive-like) behavior assessed by increased immobility in the forced swim test (FST; n = 8 per group), (M) anxiety-like behavior evaluated by increased latency to eat the food pellet in the novelty-suppressed feeding test (NSF), (N) aggressiveness identified by shorter attack latency in the resident-intruder (RI) test, and (O) social disturbances reflected by reduced time spent with the unfamiliar conspecific in the UCMS group (social novelty preference test; SNP). Data are shown for n = 9 per group (unless specified otherwise), as LSmean ± 95% CIs, except for (L–O) mean ± SEM; *P < 0.05, ^#P < 0.01, ^$P < 0.001 (post hoc comparisons for significant “treatment” × “day” interaction in general linear mixed model, or significant t test for nonrepeated measures). For detailed statistics, see Dataset S1. S, session.