Exploring the Role of the Gut-Brain Axis in Infant Brain and Behavioral Development

Background: Research is beginning to accumulate suggesting that the gut microbiome may play an important role in early postnatal brain and behavioral development. Incorporating information regarding the gut microbiome into psychobiological research thus promises to shed new light on how individual differences in brain and cognitive development emerge. Here, we examined the link between gut microbiome diversity, functional brain network connectivity, and behavioral temperament in newborn infants.
Method: Newborn infants were recruited from a local hospital as part of a larger longitudinal study. Stool samples were collected and sequenced using shotgun metagenomic sequencing. Using a resting-state functional near-infrared spectroscopy (rs-fNIRS) procedure, we measured brain connectivity in three functional brain networks (fronto-parietal network, default mode network, homologous-interhemispheric network) and one (non-functional) control network. Infant temperament was assessed using parental report.
Results: Our results show that functional connectivity networks are linked to behavioral temperament traits already within the first weeks of life. Moreover, we test and provide evidence for a potential mechanism by which the gut microbiome composition is linked to functional connectivity networks in the brain that in turn influences infant behavioral temperament.
Conclusions: The current results suggest that already in newborns a positive association between gut-microbiome diversity and functional brain connectivity patterns exists, highlighting the potential importance of the microbiome in human brain function. This study should thus be considered a first proof-of-principle study with newborns, which may serve as the foundation for systematic longitudinal work, deciphering the role of the gut microbiome in early human development and infant mental health.