Gastrointestinal Pathophysiology Following Early Life Environmental Exposure The microbiota-gut-brain axis (MGB axis) is an important pathway for maintaining health and well-being. Disruptions in the axis have been identified in numerous disease states, including inflammatory bowel disease, diabetes and autism spectrum disorder. Early development is an important life stage for normal establishment of the microbiota, development of the gastrointestinal (GI) tract and neurobiological growth and maturation, which together modulate the MGB axis.