The human body harbors trillions of commensal microbes which play a crucial role in host
development of the immune system, gastrointestinal tract, and brain. An alteration in the
composition or function of these microbes has been implicated in numerous neurological,
neuropsychological, and gastrointestinal diseases. The germ-free rodent model, devoid of
all microbes, has been increasingly used to uncover the microbial underpinnings of these
diseases and to investigate potential therapeutic treatment options. This review describes …