You are here : Home > News > 17000 brains screened for a better characterization of anatomical asymmetries

Scientific result | Brain | MRI | Medical imaging

17000 brains screened for a better characterization of anatomical asymmetries

Being part of an international consortium, the Neurofunctional Imaging Group (NeuroSpin, Bordeaux) and the Max Planck Institute for Psycholinguinstics have characterized the asymmetries of surface and thickness of the cerebral cortex of 17,141 individuals from MRI. This study published in PNAS, the largest ever done, provides a unique reference for studying the genetic basis of cerebral asymmetries and the alteration of lateralization during cognitive, neurological and psychiatric disorders.

Published on 13 June 2018


Hemispheric asymmetry is a cardinal feature of human brain organization. Altered brain asymmetry has also been linked to some cognitive and neuropsychiatric disorders. Here, the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Consortium presents the largest-ever analysis of cerebral cortical asymmetry and its variability across individuals. Cortical thickness and surface area were assessed in MRI scans of 17,141 healthy individuals from 99 datasets worldwide. Results revealed widespread asymmetries at both hemispheric and regional levels, with a generally thicker cortex but smaller surface area in the left hemisphere relative to the right. Regionally, asymmetries of cortical thickness and/or surface area were found in the inferior frontal gyrus, transverse temporal gyrus, parahippocampal gyrus, and entorhinal cortex. These regions are involved in lateralized functions, including language and visuospatial processing. In addition to population-level asymmetries, variability in brain asymmetry was related to sex, age, and intracranial volume. Interestingly, we did not find significant associations between asymmetries and handedness. Finally, with two independent pedigree datasets (n = 1,443 and 1,113, respectively), we found several asymmetries showing significant, replicable heritability. The structural asymmetries identified and their variabilities and heritability provide a reference resource for future studies on the genetic basis of brain asymmetry and altered laterality in cognitive, neurological, and psychiatric disorders.

Top page