# Socioeconomic context influences the heritability of child cortical structure

## TL;DR

This study finds that the genetic influence on children's brain structure is weaker in those from lower socioeconomic backgrounds.

## Contribution

The study demonstrates that genetic contributions to brain structure vary with socioeconomic status.

## Key findings

- Cortical thickness and surface area showed high heritability.
- Lower-SES children had cortical differences more influenced by environment than genetics.

## Abstract

Children differ in brain cortical morphometry and microstructure, which together form the structural foundation for cognition. Cortical structure is highly heritable, but whether heritability varies across socioeconomic status (SES) is unknown. In this preregistered study, we estimated single-nucleotide polymorphism (SNP)-based heritability of cortical thickness, surface area, sulcal depth, and grey-/white-matter contrast (GWC) among 9,080 US 10-year-olds. We then tested whether genetic and environmental contributions were moderated by parental SES, defined as a composite of income, education, and neighbourhood deprivation. Cortical thickness and surface area showed high heritability, while sulcal depth and GWC exhibited moderate heritability. However, among children from lower-SES backgrounds, cortical differences were less genetically related and more uniquely environmentally related, at times exceeding genetic contributions. These findings suggest that in contexts of socioeconomic disadvantage, children’s brain structure reflect lived experience more strongly than previously recognized.

Socioeconomic status influences cortical heritability. In > 9000 US 10-year-olds, cortical features were highly heritable overall, yet among lower-SES children differences were less genetic and more tied to unique environmental experiences.