Chapter 2: Development of the Microbiota–Gut–Brain Axis in Early Life

The microbiota–gut–brain (MGB) axis is important for health regulation. It is established in early life, beginning with the colonization of microbiota at birth, and subsequent maturation of the gastrointestinal tract following diet changes, antigen exposure, and coupled with significant neurodevelopment during the first years of life. Given this concurrent development, insult to any of the compartments in the MGB axis may impact proper communication, leading to impairment in signaling. In this chapter, we highlight the key steps in establishing the MGB axis in neonatal life, the known pathways involved in this communication signaling, and examples of disease where impairments in signaling play a role, including inflammatory bowel disease and autism spectrum disorders.