Cognitive ability in childhood predicts adolescent structural and functional brain development: A longitudinal study

General cognitive ability in childhood has been linked to differences in brain structure and connectivity in numerous studies. However, longitudinal examinations of links between early cognitive ability and multimodal brain development are limited. Leveraging longitudinal data from 10,495 participants of the Adolescent Brain Cognitive Development study, we examined whether childhood cognitive ability was associated with differences in longitudinal development of gray and white matter structure and resting state functional connectivity (rsFC). Linear mixed-effects models tested associations between baseline cognition-matrix reasoning, fluid cognition, crystallized cognition-and trajectories of whole-brain and regional brain measures. Brain measures included cortical thickness, surface area, and volume, fractional anisotropy, mean diffusivity, and rsFC across four time points. Across modalities, higher baseline cognitive scores were associated with slower increases in measures that normatively increased over adolescence and faster decreases for those that were found to decline. Specifically, higher childhood fluid cognition was associated with faster contraction of gray matter area and volume, and higher matrix reasoning was related to slower increases in white matter fractional anisotropy. Meanwhile, lower values in all cognitive measures-early matrix reasoning, fluid cognition, and crystallized cognition-were associated with greater increases in between-network rsFC that were absent in those with higher baseline cognitive scores. Regionally, differences in gray matter structural trajectories by cognitive ability were most prominent in the frontal lobe, while effects for white matter and rsFC trajectories varied across distributed brain systems. Findings provide insight into theories of cognition and highlight possible neurobiological pathways linking early cognition to long-term outcomes.