Using an extraordinary group of volunteers with highly localized brain injuries suffered while serving in Vietnam, scientists have been able to create a map of the specific brain regions involved in intelligence. Published in Brain: A Journal of Neurology, the study has yielded the most detailed and comprehensive picture yet of the regions involved in comprehension and working memory.
“It’s a significant challenge to find patients (for research) who have brain damage, and even further, it’s very hard to find patients who have focal brain damage,” said Dr. Aron Barbey from the University of Illinois, the study lead. These very localized brain injuries allow researchers “to draw inferences about how specific brain structures are necessary for performance.”
Creating a matrix of about 3,000 three-dimensional brain regions the scientists mapped functions against regions. “We found that general intelligence depends on a remarkably circumscribed neural system,” Barbey said. “Several brain regions, and the connections between them, were most important for general intelligence.”
In addition, the brain regions involved in forward thinking, impulse-control and other aspects of executive processing overlap significantly with regions key to general intelligence, further evidence that intelligence involves very specific brain areas working closely together.
“In fact, the particular regions and connections we found support an emerging body of neuroscience evidence indicating that intelligence depends on the brain’s ability to integrate information from verbal, visual, spatial and executive processes,” Barbey said. “This will open the door to further investigations into the biological basis of intelligence, exploring how the brain, genes, nutrition and the environment together interact to shape the development and continued evolution of the remarkable intellectual abilities that make us human.”