Deciphering the Brain-Gut Connection in Children

Baby’s Microbiome and Brain 

As a first step in understanding the relationship the microbiome might play in brain development, Bonham worked on a project while he was a senior research scientist in the Klepac-Ceraj Lab at Wellesley College to measure and describe the infant microbiome and how it transforms in the first months of life, using data from more than 1,800 babies in 12 countries. Each baby’s microbiome composition was determined by analyzing stool samples. 

“When infants shift from liquids to solid foods, we see this dramatic shift in the composition of the microbiome,” Bonham said, with certain species of microbes becoming more abundant and other species declining. Remarkably, the shift in species composition was largely consistent across the globe, despite cultural differences in lifestyle and diet. Based on these patterns, the team found they could predict a baby’s age to within three months by analyzing its microbiome.

Next, as part of a large worldwide study of children’s health called 1kD and funded by Wellcome Leap, Bonham and the research team collected microbiome and neural data from 194 typically developing children in South Africa at three times between the ages of 0 and 14 months. The neural data was collected via electroencephalogram “hairnets” placed on babies’ heads while they were shown a checkerboard pattern. Analyzing the types of brain waves produced can indicate how developed the brain’s visual cortex is. 

Bonham and his team found that the composition of the microbiome at four months of age was correlated to the level of visual cortex development between nine and 15 months. While this observation doesn’t prove that the microbiome composition is necessary for the development of the visual cortex, it raises intriguing possibilities. Bonham noted that some of the molecules produced by the microbe species that were abundant at four months are the same ones needed for the brain development seen several months later.

He plans to continue this line of inquiry at Tufts, and hopes to search for evidence that the changing microbiome composition in fact supports brain development. 

“We think that understanding the way the microbiome is related to typical development will give us insights into instances where there is some abnormality,” he said. In the future, it’s possible that analyzing the microbiome from a baby’s stool sample could be a way to screen for their risk of developmental delays.