SC Connecticut News

The human brain undergoes significant development during the final prenatal months and the first year of life. While scientists have started mapping developmental trajectories for this period, a comprehensive blueprint of healthy development is still lacking.

A recent study by Yale researchers suggests that models of brain age can be effective in tracking healthy brain development and identifying environmental factors that influence its pace. The study also highlights that advanced development is not always beneficial.

Published on November 26 in Nature Communications, the research utilized structural and functional brain images from over 600 term and preterm infants collected via MRI in the UK as part of the Developing Human Connectome Project. Researchers trained machine learning models to predict an infant's brain age using neuroimaging data.

"Typically, researchers study brain age from either structural or functional imaging data, but here we used both," said Huili Sun, lead author of the study and a Ph.D. candidate in Dustin Scheinost's lab at Yale School of Medicine. "Brain age is a novel concept in terms of taking all of the very high-dimension brain data and summarizing it into a single, but meaningful, number for an individual."

The models accurately predicted infants' ages based on whole-brain data or specific brain networks. Researchers then examined "brain age gaps," which are differences between an infant's actual age and their predicted age based on brain images. These gaps can indicate whether an infant is developing faster or slower than expected.

"We wanted to understand which type of factors might influence brain age gaps," Sun explained. "Since the brain images were collected from infants shortly after birth, many environmental factors would have had an influence during pregnancy. So we looked at maternal demographics and whether they had any associations with brain age gaps."

Maternal demographics such as age, education, mental health history, physical conditions, and substance use were considered. Maternal age showed the strongest association; higher maternal age correlated with more mature structural brain age for term infants.

Although one might assume that more developed brains are advantageous for infants, researchers found this isn't always true. "We found that while the older a child’s brain appeared to be in infancy, the better their cognitive abilities were as toddlers; their ability to regulate their behavior and emotions was worse," said Sun. "So there are costs and benefits to advanced development and following the normative trajectory is probably best according to our findings."

Future research will explore further into infancy and toddlerhood to understand genetics' role in brain age gaps. Since this study's data was European-based, conducting similar studies across different regions and cultures will be crucial.

"Brain age and brain age gaps are valuable tools for studying neurodevelopment in infants and children," stated Sun. "Establishing normative trajectories of development early in life will help identify why individuals deviate from those trajectories and could point to how and when to intervene."