Brain Connectivity May Be Linked to IQ

A new brain mapping technique has revealed a link between a person’s intelligence and how well his or her brain regions are connected, according to a new study published in the journal Neuron.

Scientists have been making great strides in mapping the human brain in an effort to understand how it relates to human behaviors, intelligence, and mental health disorders.

Now, an international team of scientists at the University of Cambridge in the U.K. and the National Institutes of Health (NIH) in the U.S., has shown that it is possible to build a map of neural data, which they call the “connectome,” by analyzing conventional brain scans taken with a magnetic resonance imaging (MRI) scanner.

For the study, the researchers compared the brains of 296 typically developing adolescent participants. Their findings were then validated in another group of 124 volunteers.

The team used a conventional 3T MRI scanner (3T represents the strength of the magnetic field); however, Cambridge has recently installed a much more powerful Siemens 7T Terra MRI scanner, which could allow this technique to give an even more accurate mapping of the human brain.

A typical MRI scan provides a single image of the brain, from which it is possible to calculate multiple structural features of the brain. This means that every region of the brain can be described using as many as ten different characteristics. If two regions have similar profiles, it can be assumed they are a connected network.

Based on this data, the researchers were able to build a map showing how well connected the “hubs” — the major connection points between different regions of the brain network — were. They discovered an association between the connectivity in the MSNs in brain regions linked to intelligence and higher order functions, such as problem solving and language.

“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,” said Ph.D. candidate Jakob Seidlitz at the University of Cambridge and NIH.

“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.”

Although IQ varied across the participants, the MSNs accounted for around 40 percent of this variation. It is possible that higher-resolution 7T scanner may be able to account for an even greater proportion of the individual variation, say the researchers.

“What this doesn’t tell us, though, is where exactly this variation comes from,” Seidlitz said. “What makes some brains more connected than others — is it down to their genetics or their educational upbringing, for example? And how do these connections strengthen or weaken across development?”

Source: University of Cambridge

Posted by Patricia Adams