Double Generalized Linear Model Reveals Those with High Intelligence are More Similar in Cortical Thickness

TL;DR

This study uses double generalized linear models to analyze how cortical thickness and its variability relate to intelligence in adolescents, revealing that higher IQ is associated with more uniform cortical thickness.

Contribution

It introduces the use of DGLM to simultaneously analyze mean and dispersion of cortical thickness in relation to intelligence, highlighting the importance of variability.

Findings

Higher IQ linked to more similar cortical thickness across individuals.

Negative correlation between intelligence and cortical thickness dispersion.

Frontal lobe thickness shows complex associations with intelligence.

Abstract

Most studies indicate that intelligence (g) is positively correlated with cortical thickness. However, the interindividual variability of cortical thickness has not been taken into account. In this study, we aimed to identify the association between intelligence and cortical thickness in adolescents from both the group's mean and dispersion point of view, utilizing the structural brain imaging from the Adolescent Brain and Cognitive Development (ABCD) Consortium, the largest cohort in early adolescents around 10 years old. The mean and dispersion parameters of cortical thickness and their association with intelligence were estimated using double generalized linear models(DGLM). We found that for the mean model part, the thickness of the frontal lobe like superior frontal gyrus was negatively related to intelligence, while the surface area was most positively associated with intelligence in the frontal lobe. In the dispersion part, intelligence was negatively correlated with the dispersion of cortical thickness in widespread areas, but not with the surface area. These results suggested that people with higher IQ are more similar in cortical thickness, which may be related to less differentiation or heterogeneity in cortical columns.