Fig. 4

Three-month-old iHip14 ^Δ/Δ mice have increased escape response and display anhedonic-like behavior. iHip14 ^Δ/Δ mice spent significantly less time immobile in the forced swim test (a; ANOVA: p = 0.0272; N = 15–19). Mice were placed in an open field under bright lighting. iHip14 ^Δ/Δ mice explored the field to the same extent as the control mice (b; ANOVA p = 0.0844; N = 24–25) but spent less time in the center (c; ANOVA: p < 0.0001; N = 24–25). iHip14 ^Δ/Δ mice spent more time in the open arms of the elevated plus maze (d; ANOVA: p < 0.0001; N = 25–34; EPM), explored the maze less (e; ANOVA: p = 0.0007; N = 25–34), and dipped their heads off the edge of the open arms more (f; ANOVA: p = 0.0001; N = 25–34) than controls. Mice were placed in an enclosed box with a brightly lit side and a dark side. iHip14 ^Δ/Δ mice spent the same amount of the time in the light box as control mice (g; ANOVA: p = 0.58; N = 13–16). Mice were allowed free access to a 2% sucrose solution and water over a 24-h period, and the total fluid consumption (g/kg of body weight; h) was measured. iHip14 ^Δ/Δ mice had no change in total fluid intake (h; ANOVA: p = 0.27; N = 14–16) but had decreased preference for the sucrose solution (i; ANOVA: p = 0.0066; N = 14–16)