Figure 1.The mechanisms of microbiota-gut-brain axis. Gut microbiota can influence the cognitive function of brain through neural signalling, endocrine, metabolic and immune pathways. 5-HT: 5-hydroxytryptamine; ACTH: adrenocorticotropic hormone; BBB: blood-brain barrier; CRH: corticotropin releasing hormone; EC: enteroendocrine cell; ENS: enteric nervous system; GABA: gamma amino butyric acid; Glu: glutamic acid; HPA: hypothalamic-pituitary-adrenal; SCFA: short-chain fatty acids.
