Children's intellectual ability is associated with structural network integrity

Abstract

Recent structural and functional neuroimaging studies of adults suggest that efficient patterns of brain connectivity are fundamental to human intelligence. Specifically, whole brain networks with an efficient small-world organization, along with specific brain regions (i.e., Parieto-Frontal Integration Theory, P-FIT) appear related to intellectual ability. However, these relationships have not been studied in children using structural network measures. This cross-sectional study examined the relation between non-verbal intellectual ability and structural network organization in 99 typically developing healthy preadolescent children. We showed a strong positive association between the network's global efficiency and intelligence, in which a subtest for visuo-spatial motor processing (Block Design, BD) was prominent in both global brain structure and local regions included within P-FIT as well as temporal regions involved with pattern and form processing. BD was also associated with rich club organization, which encompassed frontal, occipital, temporal, hippocampal, and neostriatal regions. This suggests that children's visual construction ability is significantly related to how efficiently children's brains are globally and locally integrated. Our findings indicate that visual construction and reasoning may make general demands on globally integrated processing by the brain.

Keywords: Children; Connectivity; Diffusion tensor imaging; Intelligence; Network.

Figure 1

Partial correlations between global network efficiency and intelligence scores with perceptual reasoning index (PRI) and its subtests: block design (BD), picture concepts (PC), and matrix reasoning (MR). Significant positive correlations (solid line) were found in BD and MR as well as PRI (p<0.05, after controlling for age, sex, and overall connectivity differences – i.e., the number and strength of connections).

Figure 2

Regions with significant correlations (highlighted in red, orange and yellow coloration) between local network measures and intelligence scores. Children’s block design (BD) scores showed (A) significant negative associations with network path length at each node and (B) positive associations with local efficiency (p<0.05, FDR corrected after covarying with age, sex, and the number and strength of connections). ACC, anterior cingulate cortex; IFGoper, inferior frontal gyrus (pars opercularis); ITG, inferior temporal gyrus; MCC, middle cingulate cortex; PCL, paracentral lobule; PCUN, precuneus; PoCG, postcentral gyrus; PreCG, precentral gyrus; SFG, superior frontal gyrus; SFGmed, medial superior frontal gyrus; SMA, supplementary motor area; SMG, supramarginal gyrus; STG, superior temporal gyrus.

Figure 3

Rich club connectivity. Significant rich club nodes (red spheres in the left diagram) were found in the wide range of degree k>25 including the superior frontal (orbital) gyrus (SFGorb), putamen (PUT), hippocampus (HIP), inferior temporal gyrus (ITG), precuneus (PCUN), lingual gyrus (LING), middle occipital gyrus (MOG), and superior occipital gyrus (SOG). Structural connectivity, as measured by averaged fractional anisotropy (FA) value of fiber tracts, was positively correlated among rich club nodes with perceptual reasoning index (PRI), while children’s block design (BD) score was correlated for rich club, feeder (blue), and local nodes (yellow) (p<0.05 with covariates of age, sex, and the number and strength of connections).