The gut microbiota is an essential part of the gastrointestinal tract and recent research, including clinical and preclinical studies, shed light on the interaction between the gut and the brain. A rising amount of evidence strongly proves the involvement of gut microbes in brain function and their contribution in altering behavior, mood, and ultimately in the pathogenesis of certain neurological conditions. The gut microbiota produces and modulates neurotransmitters such as GABA, serotonin, dopamine, glutamate, etc. Furthermore, there is a presence of a biological link between the microbiota, immune signaling, and CNS suggesting that microbial metabolites could regulate both neurological and immunological activities in the brain. Thus, this review focuses on the bidirectional communication between the gut and brain, its impact and role in the modulation of various neurological disorders, such as schizophrenia, depression, anxiety, etc., and attempts to explore the underlying mechanism for the same. The article also discusses studies involving germ-free mice, studies on the effects of faeces transfer of microbiota, and research involving gut microbiota composition in animal models. The effects of probiotics and prebiotics on neurological disorders are also discussed, along with the clinical studies for each of them. In a nutshell, extensive studies are required to explore this bidirectional communication between the gut and brain, which might help researchers develop new therapeutic targets in treating neurological disorders and increase our understanding of the gut-brain axis.
