Early life adversities associated with reduced brain connectivity and cognitive performance

Early life adversities associated with reduced brain connectivity and cognitive performance

Mass General Brigham's investigators have linked difficult early life experiences to reduced quality and quantity of white matter communication pathways throughout the adolescent brain. This reduced connectivity is also associated with lower performance on cognitive tasks. However, certain social resilience factors such as neighborhood cohesion and positive parenting may have a protective effect. Results will be published inProceedings of the National Academy of Sciences (PNAs).

White matter is the communication pathways that allow brain networks to carry out the functions necessary for cognition and behavior. They develop throughout childhood, and childhood experiences can influence individual differences in white matter maturity. Lead author Sofia Carozza, PhD, and senior author Amar Dhand, MD, PhD, of the Department of Neurology at Brigham and Women's Hospital, a founding member of the General Brigham Healthcare System, wanted to understand the role this process plays in cognition as children reach adolescence.

The aspects of white matter that show a relationship to our early life environment are much more ubiquitous throughout the brain than we thought. Rather than just one or two areas important for cognition, the entire brain is related to the adversities someone might experience early in life. “

Sofia Carozza, PhD, lead author

The team examined data from 9,082 children (about half of them girls with an average age of 9.5) in the Adolescent Cognitive Development Study (ABCD). This study, funded by the National Institutes of Health and conducted at 21 centers across the United States, collected information on brain activity and structure, cognitive ability, environment, mood and mental health. Researchers examined several categories of early environmental factors, including prenatal risk factors, interpersonal adversity, household economic deprivation, neighborhood adversity, and social resilience factors.

Carozza and Dhand used diffusion imaging scanning of the brain to measure the fractional anisotropy (FA)-A method to estimate the integrity of white matter connections, and the number of counts, an estimate of their strength. They then used a computational model to compare how these white matter characteristics relate to both childhood environmental factors and current cognitive abilities such as language skills and mental arithmetic.

Their analysis revealed widespread differences in white matter connections throughout the brain that vary from children's early environments in the child's early life. Specifically, the researchers found lower quality white matter connections in parts of the brain tied to mental arithmetic and receptive language. These white matter differences accounted for part of the relationship between adverse life experiences in early childhood and lower cognitive performance in adolescence.

“We are all embedded in an environment, and features of that environment, such as our relationships, home, neighborhood, or material circumstances, can grow our brains and bodies, which in turn influences what we can do with them,” Carozza said. “We should work to ensure that more people can have those stable, healthy home experiences that the brain expects, especially during childhood.”

The researchers note that their study relies on observational data, meaning they cannot make strong causal conclusions. Brain imaging was also only available in a single time point, which offered a snapshot but did not allow changes to be tracked over time. Prospective studies that follow children over time and collect information at multiple time points were needed to definitively link adversity and cognitive performance.

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