Funding Source: Wellcome Leap 1kD – Brain structure and function are sensitive and responsive to environmental conditions and individual experiences such as nutrition, gut microbiome, household environment and levels of stress. The main goals of this multi-scale, and multi-modal study is to comprehensively characterize the development of executive functions over the first 1000 days of life in two African cohorts (South Africa and Malawi) to identify developmental patterns, windows for intervention, and inform on therapeutic agents. Here at Wellesley, we will characterize the gut microbiome collected over the first two years of life and link the acquisition of the microbiome to executive functions.