Genetics of brain fiber architecture and intellectual performance
Source: The Journal of Neuroscience
2009 Feb;7(29):2212-2224.
Author: Chiang MC, Barysheva M, Shattuck DW, Lee AD, Madsen SK, Avedissian C, Klunder AD, Toga AW, McMahon KL, de Zubicaray GI, Wright MJ, Srivastava A, Balov N, Thompson PM PubMed ID: 19228974
Abstract:
The study is the first to analyze genetic and environmental factors that affect brain fiber architecture and its genetic linkage with cognitive
function.Weassessed white matter integrity voxelwise using diffusion tensor imaging at high magnetic field (4 Tesla), in 92 identical and
fraternal twins. White matter integrity, quantified using fractional anisotropy (FA), was used to fit structural equation models (SEM) at
each point in the brain, generating three-dimensional maps of heritability. We visualized the anatomical profile of correlations between
white matter integrity and full-scale, verbal, and performance intelligence quotients (FIQ, VIQ, and PIQ). White matter integrity (FA) was
under strong genetic control and was highly heritable in bilateral frontal (a20.55, p0.04, left; a20.74, p0.006, right), bilateral
parietal (a20.85, p0.001, left; a20.84, p0.001, right), and left occipital (a20.76, p0.003) lobes, and was correlated with FIQ
and PIQ in the cingulum, optic radiations, superior fronto-occipital fasciculus, internal capsule, callosal isthmus, and the corona radiata
( p0.04 for FIQ and p0.01 for PIQ, corrected for multiple comparisons). In a cross-trait mapping approach, common genetic factors
mediated the correlation between IQ and white matter integrity, suggesting a common physiological mechanism for both, and common
genetic determination. These genetic brain maps reveal heritable aspects of white matter integrity and should expedite the discovery of
single-nucleotide polymorphisms affecting fiber connectivity and cognition.