White matter microstructure correlates of mathematical giftedness and intelligence quotient

Abstract

Recent functional neuroimaging studies have shown differences in brain activation between mathematically gifted adolescents and controls. The aim of this study was to investigate the relationship between mathematical giftedness, intelligent quotient (IQ), and the microstructure of white matter tracts in a sample composed of math-gifted adolescents and aged-matched controls. Math-gifted subjects were selected through a national program based on detecting enhanced visuospatial abilities and creative thinking. We used diffusion tensor imaging to assess white matter microstructure in neuroanatomical connectivity. The processing included voxel-wise and region of interest-based analyses of the fractional anisotropy (FA), a parameter which is purportedly related to white matter microstructure. In a whole-sample analysis, IQ showed a significant positive correlation with FA, mainly in the corpus callosum, supporting the idea that efficient information transfer between hemispheres is crucial for higher intellectual capabilities. In addition, math-gifted adolescents showed increased FA (adjusted for IQ) in white matter tracts connecting frontal lobes with basal ganglia and parietal regions. The enhanced anatomical connectivity observed in the forceps minor and splenium may underlie the greater fluid reasoning, visuospatial working memory, and creative capabilities of these children.

White matter integrity and cognitive performance in school-age children: A population-based neuroimaging study

“…In an early study of roughly 50 children, 5 to 18 years old, Schmithorst et al (2005) found positive associations between white matter microstructure (i.e., DTI metrics) and intelligence, irrespective of age and sex. A more recent study of 36 children and adolescents 11 to 15 years of age also showed a positive association between white matter microstructure and intelligence (Navas-Sanchez et al, 2014). These studies show IQ to be linked to white matter microstructure in multiple regions, including frontal, parietal and occipital lobes, and the corpus callosum.…”

“…Previous work in children has demonstrated associations between white matter microstructure and IQ (Navas-Sanchez et al, 2014;Schmithorst et al, 2005). Schmithorst et al (2005) used a voxel-based approach to show positive associations between IQ and FA in multiple regions, particularly association bundles connecting frontal, parietal and occipital lobes.…”

“…The same study also showed negative associations between IQ and MD, mostly in frontal white matter. Using voxelbased and region-of-interest methods, Navas-Sanchez et al (2014) found associations between IQ and FA, primarily in the corpus callosum. In the present study, the association fibers included in these analyses, especially the SLF, overlap well with voxel-wise clusters observed in Schmithorst et al (2005).…”

“…First, to assess whether global measures of white matter integrity predict cognitive performance, a number of tracts commonly reported in the literature were combined into a single latent factor ("global factor"). Large, commonly studied fiber tracts were selected for inclusion in the global factor based on previous reports (Navas-Sanchez et al, 2014;Schmithorst et al, 2005) and detailed descriptions of the anatomy and function of the tracts (Schmahmann et al, 2007) in order to encompass a broad range of cognitive abilities. Prior to SEM analyses, in order to ensure that the global DTI latent predictor was statistically valid, a confirmatory factor analysis (CFA) was run.…”

“…While studied to a lesser extent than white matter maturation, associations between white matter and cognitive performance have also been examined in children (Erus et al, 2015;Fryer et al, 2008;Johansen-Berg et al, 2007;Muetzel et al, 2008;Navas-Sanchez et al, 2014;Schmithorst et al, 2005). In an early study of roughly 50 children, 5 to 18 years old, Schmithorst et al (2005) found positive associations between white matter microstructure (i.e., DTI metrics) and intelligence, irrespective of age and sex.…”