There is compelling evidence for a critical role of the maternal and infant gut microbiome in early infant brain
neurodevelopment. Temporal milestones in postnatal infant gut microbiome development align with changes in
early infant brain development, suggesting functional relationships between these two pivotal events. The
premise of our proposal is based on a wealth of studies and new preliminary analyses reported below linking
maternal prenatal anxiety (PNA), a prominent prenatal maternal risk factor, and child neurodevelopment. We
hypothesize that the prenatal maternal microbiome and its influence on newborn neurodevelopment is shaped
by PNA, and that early infant cognition is determined by mother-to-infant microbiome transfer, postnatal
development and biosynthesis of microbiota-derived neuroactive metabolites (NAMs). Our study is framed by a
proposed developmental model that includes two major components; prenatal anxiety and developmental phase
trajectories of the infant gut microbiome. The proposed model has scientific as well as practical strengths, as it
leverages a wealth of existing data collected as part of a large, prospective longitudinal and diverse pregnancy
cohort that has been followed from the first trimester through the child’s 4th year, with extensive longitudinal
characterization of prenatal exposures, child microbiome and other key biological samples, and child
neurodevelopment assessed longitudinally that will enable important and previously neglected incorporation of
potential confounds. We use these components to test the central hypothesis that neurodevelopment is
dependent on age-driven biosynthesis of NAMs through the postnatal period of infant gut-microbiome (IGM)
development. In Aim 1, we use metagenomic analysis of the prenatal maternal vaginal microbiome (MVM) to
identify species and functional biosynthetic pathways for NAMs associated with PNA. We also assess the
potential transfer of maternal anxiety through the initial colonization of the infant gut microbiome by an anxiety
“imprinted” MVM. In Aim 2, we use metagenomic and metabolomic analyses to determine the association
between key stages of IGM development and differential synthesis of NAMs over the first year, attending to
confounds and competing exposures, most notably, maternal diet and infant feeding. In Aim 3, we apply this rich
data to predict neurocognitive assessments from age 1 to 4 years to formally test the temporal relationship
between microbiome phase and neurodevelopment in the first year of life and durability of the microbiota-
neurodevelopment relationship through 4 years of age. The scientific impact of the study will be on advanced
understanding of the role of prenatal exposures; documenting sources of between- and within-individual
differences in the IGM through the first years of life; identifying NAMs with a possible mechanistic role in the
MGB axis; documenting a potentially broad and persistent impact on neurodevelopment.