University of Cambridge researchers have found a correlation between how well connected an individual's brain regions are and their intelligence. Their research was published last month in Neuron.
Using a conventional 3T MRI scanner to map the wiring of the brain, the team compared the brains of 296 typically developing adolescent volunteers. Their results were then validated in a cohort of a further 124 volunteers.
A typical MRI scan will provide a single image of the brain. The researchers showed that if two regions have similar profiles, then they are described as having morphometric similarity and it can be assumed that they are a connected network.
Using these morphometric similarity networks (MSNs), the researchers were able to build up a map showing how well connected the hubs—the major connection points between different regions of the brain network—were. They found a link between the connectivity in the MSNs in brain regions linked to higher order functions—such as problem solving and language—and intelligence.
"We saw a clear link between the “hubbiness” of higher-order brain regions—in other words, how densely connected they were to the rest of the network—and an individual's IQ," explains Ph.D. candidate Jakob Seidlitz. "This makes sense if you think of the hubs as enabling the flow of information around the brain—the stronger the connections, the better the brain is at processing information."
While IQ varied across the participants, the MSNs accounted for around 40% of this variation—it is possible that higher-resolution multi-modal data provided by a 7T scanner may be able to account for an even greater proportion of the individual variation, says the researchers.
"This could take us closer to being able to get an idea of intelligence from brain scans, rather than having to rely on IQ tests," says professor Ed Bullmore, head of psychiatry at Cambridge. "Our new mapping technique could also help us understand how the symptoms of mental health disorders such as anxiety and depression or even schizophrenia arise from differences in connectivity within the brain."