White matter structure and genetics may reveal links to brain-related diseases

thank you. Listen to this article in the player above. ✖

new study used brain imaging of more than 30,000 individuals to map genetic associations with structural differences in the brain’s white matter, showing possible associations with several hereditary brain-related disorders. . This research scientific progress.

Brain structure and genetics

two different types The tissues that make up our brain are gray and white matter. Gray matter is common in functionally important regions of the brain, such as the cerebellum and cerebral cortex, and the importance of white matter is sometimes overlooked.

Named for the color of the fatty myelin sheath that surrounds the axons of nerve cells in the brain, white matter conducts nerve signals along connections between different regions of the brain and is part of the structural ‘connectome’. Form a large network as a department.

Research so far suggested that alterations in white matter structure may be associated with a genetic predisposition to several psychiatric and neurological conditions, such as major depressive disorder and schizophrenia. However, various brain imaging These methods have not been successful in linking structural changes in white matter to specific genes or locations within the genome (locus).

Studies investigating how DNA variants, genes, and pathways alter white matter structure are desperately needed to understand how this influences predisposition to brain damage.

In the current study, researchers aimed to determine how genes or genetic variants affect the white matter connectome and potential links to brain disorders and behavioral traits.

written on a blank sheet of paper

Researchers analyzed brain imaging and genotyping data from 30,810 adult participants. UK BiobankThey looked at brain imaging obtained using diffusion tensor imaging (DTI) – a type of MRI scan – applied a technique called tractography It visualizes white matter fibers (tracts) in 3D to identify common structural variations.

They then performed a genome-wide association analysis using the participants’ genotyping data and found 325 loci associated with the identified structural alterations.

“Nerve fibers in the brain are arranged in bundles, linking different parts of the brain together to form larger networks. Hundreds of variants associated with variation were found in the genome.” Professor Clyde FranksSenior Fellow at the Max Planck Institute for Psycholinguistics and senior author of the study.

Furthermore, using previously published genetic data collected over the human lifetime, Franks and colleagues found that these genetic variants tended to be most active during embryonic and fetal brain development. discovered. Their roles include generating new neurons and “wiring” them to their correct location in the brain, suggesting that some structural changes may be established early in life. doing.

The findings also shed light on a possible link between these structural changes and brain-related disorders. “People with a higher genetic predisposition to mental disorders tended to have slightly reduced amounts of white matter connections in their brains, which were very widespread throughout the brain, but varied somewhat from disorder to disorder,” Franks explained. For example, genetic predisposition to autism was associated with white matter connectivity in brain regions associated with attention and working memory, whereas predisposition to bipolar disorder was associated with brain regions involved in mood. I was.

“These findings suggest that a reduced network of white matter connections is a risk factor for psychiatric disorders, and that the specific connections affected may affect the exact types of psychiatric traits a person is prone to. It suggests that

Connectome and other brain functions

Franks mentioned some limitations of the study, emphasizing that the methodology used is limited by the need to analyze over 30,000 brain images in a few months. “There are other computational approaches that have advantages in terms of allowing finer-grained functionality of the white matter network, but that would have made our runtime last several years,” he explained. The approach has worked well enough to identify many new genetic influences on white matter in the brain, but there is certainly more to discover.”

Francks also explained that his department’s area of ​​expertise, the study of language centers in the brain, is currently the subject of further research. “Future studies on the genetics of dyslexia and other language-related traits and disorders will pay particular attention to genes involved in the wiring of language networks in the brain.”

reference: Sha Z, Schijven D, Fisher S, Francks C. The genetic architecture of the human brain white matter connectome. 2023. Science.advance sale. Doi: 10.1126/sciadv.add2870

Professor Clyde Francks was talking with Dr. Sarah Whelan, science writer at Technology Networks.