Can a poverty-stricken childhood influence the wiring of a child's brain?

According to a recent study carried out by Washington University School of Medicine in St. Louis, Missouri, poverty-stricken childhoods may influence the wiring within a child's brain.

The study, which was published on June 27th in the JAMA Network Open medical journal, suggests a link between household poverty and the brain's white matter tracts, which plays a critical role in communication between the various brain regions, and helping the brain process information.

White matter is used to describe the densely-packed nerve fibres in the brain, getting their white colour from the fatty substance that surrounds nerve fibres. This fatty coating is responsible for the rapid transmission of information along nerve cell tracts, with the organisation and connectivity between these tracts supporting learning and communication across brain regions.

These findings stem from accumulated data from the Adolescent Brain Cognitive Development (ABCD) Study, the most extensive, long-term study of brain development and child health conducted in the United States. Washington University is a national leader in studying the developing brain and is one of the few sites around the country participating in the ABCD study, which has followed the cognitive journeys of nearly 12,000 children, beginning at the ages 9 to 10, for at least a decade.

Zhaolong Li, first author and neuroimaging research technician in the Department of Psychiatry, said: "White matter integrity is very important in brain development. For example, weaknesses in white matter are linked to visuospatial and mental health challenges in children. If we can capture how socioeconomic status affects white matter early on in a child's life, the hope is we can, one day, translate these findings to preventive measures."

The researchers also discovered that childhood obesity and lower cognitive function could explain poverty's influence on differences in white matter. Children who generally grow up in poverty tend to have a higher risk of obesity and score considerably lower on tests of cognitive function when compared to their peers in higher-income neighbourhoods and households.

Scientists used the publicly available ABCD database in order to monitor water movement as an indicator of white matter integrity in the brain scans of over 8,800 children aged between 9 and 11. Much like how rocks and boulders impact the water flow in a river, diverse brain cell structures create barriers that hinder water diffusion.

Subsequently, the researchers found less directional movement of water molecules in the brains of children living in poverty, which signifies structural changes in white matter regions. High water content was also located within the spherical spaces in the brain, hinting at a possible neuro-inflammation in those living in poverty-stricken childhoods.

Scott Marek, PhD, co-corresponding author and an assistant professor of radiology and psychiatry, commented on the study, saying: "Wealth and income inequality are accelerating in the U.S. We and others are starting to scratch the surface of how inequality may harm the developing brain and affect mental health outcomes."

Marek concluded by stating: "Our findings emphasise shifting away from the thinking that socioeconomics is a unitary construct. It's not schools or parenting alone that matter for brain health. It's likely the collection of many neighbourhood and familial life factors."

Adding to this, Tamara Hershey, PhD, professor of cognitive neuroscience, psychiatry and radiology, said: "Our finding that obesity and cognitive enrichment may be relevant mediators, if confirmed, would provide strong support for managing healthy weight and encouraging cognitively stimulating activities to support brain health in disadvantaged children."

Hershey concluded: "We hope this work encourages future studies to examine modifiable health risk factors in large and longitudinal samples that would one day translate to intervention."