Anhedonic mice display lasting increases in home cage activity during the dark phase of the day. (A) During the dark phase of the diurnal cycle, mean time of horizontal movement of the anhedonic group (dashed line) is significantly elevated during 2nd-4th weeks of stress, and during weeks 1 and 2 after the termination of the stress procedure, as compared to the non-anhedonic (plain thick line) and control (plain thin line) groups (*p < 0.05 vs. control group and # p < 0.05 vs. non-anhedonic group; Mann-Whitney). This parameter does not change in the non-anhedonic group throughout the entire experiment (p > 0.05 vs. control group). (B) During the light phase of the day, no difference between the groups in home cage activity is observed (p > 0.05). Data are expressed as mean ± (SEM).