SYP and post-traumatic stress disorder: Hippocampal function-related genes (BDNF, PSD-95, Synaptophysin, Cholecystokinin, Calbindin 1, Syntaxin 1a, NeuroD6, and NeuroD2) were significantly downregulated in the hippocampus of PTSD mice, although they were restored by HFE treatment.