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Researchers compared “resting functional connectivity” networks in a small group of collegiate cross-country runners with those of healthy peers.

The book The Runner’s Brain told runners how their minds could change their running. Now a University of Arizona study says the reverse might be true as well.

Parts of our brains remain active even while we rest. They form a pattern visible in functional connectivity MRIs, which track oxygenated blood flow in the brain. When Gene Alexander, UA professor of neuroscience, and his colleagues compared these “resting functional connectivity” networks in a small group of collegiate cross-country runners with those of healthy peers, they found significant differences.

“The ones that we saw that were correlated with the network, involving the frontal cortex, are the ones that we were predicting as being important, because they engage in planning, executive function and working memory kinds of areas of the brain," said Alexander.

The results appeared in the Nov. 20 edition of Frontiers in Human Neuroscience.

Researchers used functional connectivity MRI (fcMRI), an imaging technique that spots activity patterns by tracking changes in the flow of oxygenated blood in the brain, to monitor subjects' idle brains.

“Essentially, we have people lying in a scanner, at rest, while they’re awake. The brain is active even in those cases where you’re not thinking about specific kinds of cognitive tasks, and these areas of the brain are associated with each other in specific ways, forming a pattern,” said Alexander.

Alexander said this paper expanded the growing body of studies regarding exercise’s effects on the brain.

“There’s been a great deal of work looking at older adults to see how exercise benefits the brain in aging. And so, in this case, we were really trying to see whether we could identify effects in young people,” said Alexander.

Neuroscientists can look at brain connections in a number of ways. Structurally, they might consider which areas have the strongest or most plentiful neural connections. But they might also look for functional connectivity: patterns of areas that become active (or not), in sync, during some activity — or, as in the case of this study, while resting.

This “resting-state functional connectivity” comprises the areas — or, more precisely, networks — that are active when the brain is at rest, like an idling engine or a just-booted computer. The study looked at three such networks that link motor control with executive functions like working memory and planning: the default mode network, the frontoparietal network and the motor network.

Alexander said that these networks could play a key role in the effects of aging and neurodegenerative diseases.

“These networks have implications, because they do engage areas of the brain that we think are important as we age, that involve executive motor and executive planning ability, decision making, processing of multitasking kinds of activities.”

The study is part of a larger research program in that examines the relationship between physical activity and brain activity, and how they affect aging and the risk for disease.

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How these functional connectivity changes might affect cognitive function — processes like thinking, reasoning and remembering — remains a question for future research. But if they pose a benefit, Alexander and his colleagues will want to know whether that benefit carries forward in the brain as it ages. If so, it could add to the growing body of research suggesting that exercise can improve cognition and functional connectivity as we age.

“Do you find that these kinds of structural or functional differences in the brain afford some kind of resilience to the effects of aging? And that’s simply a question we don’t know, but an important one.”