It’s no surprise that our brains our wired differently — that’s what makes some of us good at math and gives others perfect pitch or a way with words. A new brain imaging study, published 6 February in Neuron, maps out the regions in which neural connections seem to vary most among people.

The study focused on typical adults, but lead investigator Hesheng Liu, assistant professor of radiology at Harvard Medical School in Boston, is beginning to use the same approach to study connectivity differences in autism.

Liu and his collaborators used an approach called resting-state functional magnetic resonance imaging, also referred to as functional connectivity. This technique measures synchrony between different parts of the brain while the participant lies quietly in the scanner.

The researchers scanned 23 typical adults five times over a period of six months and compared differences in connectivity among them.

They found that the greatest variability is in parts of the brain involved in synthesizing different types of information, as well as in networks involved in higher-level cognitive tasks, such as attention. Brain systems involved in sensory and motor function and vision vary the least.

The most highly variable regions are those that have evolved most recently. They also overlap with those that previous functional connectivity studies have linked to individual differences in behavior or cognitive performance, such as memory, anxiety and intelligence.

The findings may be important for interpreting results from functional connectivity studies. Brain imaging studies often average data from a number of people, an approach that might miss out on differences in these regions.

The approach may also lend insight into developmental and psychiatric disorders. For example, do these circuits range beyond the normal level of variability in people with these conditions? Or is it the more stable regions that tend to be disrupted in these disorders? 

Liu says he is particularly interested in looking at individual differences in hemispheric specialization — meaning one hemisphere is specialized for certain tasks, such as language — in the autism population. Previous research has linked the degree of asymmetry in brain wiring in the hemispheres to severity of autism symptoms.