The three-dimensional shape of the cerebral cortex, the wrinkled outer layer of the brain controlling many functions of thinking and sensation, strongly correlates with ancestral background, researchers at the University of California, San Diego have found.
The study could lead to more precise studies of brain anatomy going forward, and could eventually open the door to more personalized medicine approaches for diagnosing and treating brain diseases.
“If we can account for a large percentage of brain structure based on an individual’s genes, we’re in a better position to detect smaller variations in the brain that might be important in understanding disease or developmental issues.”
High Degree of Accuracy
Researchers found they could predict with “a relatively high degree of accuracy an individual’s genetic ancestry based on the geometry of their cerebral cortex.”
No relationship between brain shape and functional or cognitive abilities was found, Dale said, but instead a hoard of information about how minute differences in brain geometry could be correlated with genetic lineage.
First author, Chun Chieh Fan, MD, a graduate student in cognitive science, said:
“The geometry of the brain’s cortical surface contains rich information about ancestry. Even in the modern contemporary U.S. population, with its melting pot of different cultures, it was still possible to correlate brain cortex structure to ancestral background.”
Cortex Folding and Gyrification Patterns
The researchers analyzed data from the Pediatric Imaging, Neurocognition and Genetics (PING) study, a major data collection project funded by the National Institute on Drug Abuse and the National Institute of Child Health and Human Development in 2009.
The project collected neuroimaging and genotyping data from more than 1,200 children and adolescents at 10 sites in the United States to create a data repository to advance research efforts worldwide. UC San Diego was the coordinating center for the PING study and Dale and Jernigan were its co-principal investigators.
Co-author Terry Jernigan, PhD, professor of cognitive science, psychiatry and radiology, said:
“We looked to see how well we could predict how much genetic ancestry they had from Africa, Europe and so forth. There were various systematic differences, particularly in the folding and gyrification patterns of the cortex. Those patterns were quite strongly reflective of genetic ancestry.”
Dale said differences in cortex shapes between the various ancestries are “subtle, but systematic,” adding that understanding these differences will be important in refining future brain research and also in creating appropriate standards of comparison for the various ancestral groups, and for those which are a mixture of different groups.