New MRI brain mapping method links between connectivity, IQ

Researchers have found a correlation between interconnectivity of brain regions and individual intelligence using brain MRI. The study, led by scientists at the University of Cambridge in the U.K., was published Dec. 21, 2017 online in Neuron.

“Despite decades of neuroscience research using MRI, there is still a lack of validated and widely accessible tools for mapping the large-scale network architecture of anatomically connected regions in an individual human brain,”

wrote lead author Jakob Seidlitz, PhD student in Oxford-Cambridge Scholars Program, and colleagues.

The team also included researchers from the National Institutes of Health.

The group analyzed MRI of 296 young adult volunteers, with results later validated in a group of 124 volunteers. Using a standard 3T scanner, researchers were able to demonstrate that if two regions of the brain have similar profiles, these areas have morphometric similarity and thus a connected network or morphometric similarity network (MSN). This assumption was backed up by using publically available MRI data on a group of 31 juvenile rhesus macaque monkeys to compare to “gold standard” connectivity estimates in the species.

These MSNs were then used to create a map demonstrating the relationship between brain “hubs”—major connection points between the connectivity in the MSNs in brain regions linked to higher order functions—and individual intelligence.

“Morphometric similarity mapping provides a novel, robust, and biologically plausible approach to understanding how human cortical networks underpin individual differences in psychological functions,” wrote Seidlitz et al.

They found a link between the density of connectedness of hubs of higher order brain regions and an individual’s IQ. In fact, MSN nodes accounted for nearly 40 percent of participant variation in IQ.

“The availability of a new method for mapping the anatomical connectome of a single human is likely to be helpful in understanding how its network topology relates to the cognitive or psychological functions of the brain,” according to researchers in the study. “[I]t is particularly important to understand more clearly how integrative elements of connectome topology like hubs …  might be linked to cognitive processing.”