a, b, CRS induces increased immobility and decreased latency to immobility in the FST (a) and decreases sucrose preference in the SPT (b). n = 8, 14 mice (a) and 7, 8 mice (b) for control and CRS group, respectively. c, CRS increases locomotion in the OFT. n = 8 mice per group. d, e, Ketamine suppresses immobility of CRS mice in the FST (d) and increases sucrose preference (e) in CRS mice. f, Ketamine decreases locomotion of CRS mice in the OFT. n = 8, 12 mice (d, f) and 14, 21 mice (e) for saline and ketamine groups, respectively. g–j, Burst firing is significantly increased in CRS mice, and this increase is reversed by ketamine (i.p., 10 mg kg–1). g, Whole-cell patch-clamp recording sites across different subregions of LHb in mice. h, Pie charts illustrating the per cent abundance of the three types of LHb neurons. i, Bar graph illustrating the percentage of burst- and tonic-type spikes in all spikes recorded. j, Histogram of distribution of inter-spike intervals (ISIs). n = 63, 69, 57 neurons, 4 control, saline-treated mice, 3 CRS, saline-treated mice and 5 CRS, ketamine-treated mice. Data are mean ± s.e.m.; *P < 0.05, **P < 0.01, ****P < 0.0001, n.s., not significant. Two-tailed Mann–Whitney test and unpaired t-test (a– f), Chi-square test (h), Fisher’s exact test (i).