FMT from (S)-ketamine -treated CCI mice can ameliorate the working memory impairment, but not mechanical allodynia and thermal hyperalgesia in CCI mice. a: flow chart of fecal sample collection from the donor mice. b: the spontaneous alternation in Y-maze of the donor mice (one-way ANOVA: F (2, 27) = 8.112, p = 0.0017). c: the protocol of the FMT experiment. d: OFT: (one-way ANOVA: F (3, 36) = 0.1794, p = 0.9097). e: PWT: (one-way ANOVA: F (3, 36) = 36.90, p < 0.0001). f: PWL: (one-way ANOVA: F (3, 36) = 22.98, p < 0.0001). g: number of arm entries in Y-maze (one-way ANOVA: F (3, 36) = 1.940, p = 0.1405). h: the spontaneous alternation in Y-maze (one-way ANOVA: F (3, 36) = 9.594, p < 0.0001). i: BDNF levels in hippocampus (one-way ANOVA: F (3, 36) = 4.410, p = 0.0097). j: HDAC2 levels in hippocampus (one-way ANOVA: F (3, 36) = 1.124, p = 0.3522). N = 10/group. *p < 0.05; **p < 0.01; ***p < 0.001. FMT, fecal microbiota transplantation; FMT1, sham + saline-treated sham mice feces; FMT2, sham + saline-treated CCI mice’ feces; FMT3, CCI + saline-treated CCI mice feces; FMT4, CCI + (S)-ketamine-treated CCI mice feces.PWT, paw withdrawal threshold; PWL, paw withdrawal latency; OFT, open field test; CCI, chronic constriction injury.