Figure 1.

The microbiota-gut-brain-axis. Gut microbiota affect gut permeability and brain function through multiple humoral and neuronal signals and routes, including vagal and spinal afferents as well as circulating metabolites and immune cells. These pathways are important to maintain host homeostasis and gut function. Imbalances can lead to altered neuron function and information processing in the enteric, peripheral, and central nervous system and inflammation, which affects the host health status. Bioactive signals emerge from gut microbiota which releases a multitude of bioactive substances including neurotransmitters such as serotonin (5-HT), and short-chain fatty acids (SCFAs). Created with BioRender.com.