Abstract

Purpose The aim of this study is to better understand the neural substrate of intelligence in children, through the characterization of the brain's structural connectivity (graph measures), as well as the major white matter (WM) fibers microstructure.

Materials and methods Fourty-three children (8 to 12 years) were include in this study. MRI acquisition included conventional and diffusion tensor imaging sequences. Children also underwent neuropsychological tests, providing the ten WISC-subtests. A factor analysis was performed to explore the inter-correlations of WISC-IV subtests and to extract intelligence domains as well as the general intelligence factor (g-score). Correlations between the intelligence domains and both graphs and diffusivity metrics were also explored.

Results Global graph metrics revealed a strong relationship between high intelligence scores and brain network homogeneity (high density and low modularity), mainly in the temporal and parietal lobes. Furthermore, quantitative WM fiber-bundle analysis showed an increased axonal density in the major WM fiber-bundles that was associated to increased intelligence performances.