Ann Arbor Times

Researchers from the University of Michigan and Columbia University have found that certain regions of the brain in people with Alzheimer’s disease tend to reorganize more frequently while at rest than in people without the condition. The study, published in the Journal of Alzheimer’s Disease, investigated neural flexibility—the brain's ability to shift its functional networks—using functional MRI data from 862 older adults.

Eleanna Varangis, assistant professor at the U-M School of Kinesiology and first author of the study, explained: “Our brain is always organizing and reorganizing regions into different functional networks in order to make sure it has the resources it needs to complete a variety of cognitive tasks. We found that in Alzheimer’s disease the brain tends to reorganize more frequently.

“Overall, our paper suggests that we can use information about the way our brain organizes into functional networks to possibly help identify whether or not someone has Alzheimer’s disease.”

The research analyzed participants from three groups: cognitively normal individuals, those with mild cognitive impairment, and those diagnosed with Alzheimer’s disease. It aimed to determine whether neural flexibility was altered by Alzheimer’s-related damage and if this metric could predict who among healthy individuals might develop Alzheimer's later on.

Findings indicated that neural flexibility was higher across all measured brain regions in participants with Alzheimer’s compared to cognitively normal peers. In addition, within specific networks such as the visual network, those with mild cognitive impairment also showed increased flexibility compared to healthy individuals. Among 617 healthy participants followed over 11 years, 8.6% developed dementia—a rate consistent with national averages for older adults.

“While this was only a modest effect, it is a good hint that activity in these visual regions may be telling us something about risk for Alzheimer’s disease years before formal diagnosis,” Varangis said. “Since we think of cognitive impairment being the primary symptom of Alzheimer’s disease, the finding that this sensory network was the one that predicted Alzheimer’s conversion was a bit unexpected, but it wasn’t necessarily surprising.

“In typical Alzheimer’s disease, the brain pathology that causes the disease does not progress to sensory regions until later stages of the disease. It could be that these regions show more flexibility because they are among the healthier regions of the brain that have not yet been affected by Alzheimer’s disease pathology.”

Varangis noted that although flexibility is generally considered positive for brain health, increased neural flexibility during rest could indicate dysfunction as Alzheimer's progresses.

“But once we see the disease process setting in, it could be the case that if we’re just resting and we are showing this frequent reassignment of brain regions to different functions it could be that parts of the brain aren’t working the way that they should be,” she said.

She emphasized that using neural flexibility as a diagnostic tool remains experimental at this stage.

“The positive here is that I think a lot of people think that in neurodegenerative disease you see this general brain slowing over time,” she said. “But to me, these findings also speak to the fact that the brain is such a dynamic organ, that even when folks are experiencing these cognitive changes or getting worse over time, there’s so much flexibility for our brains to adapt, which I think is also a sign of hope and resilience.”

The study included co-authors Jun Liu, Yuqi Miao, Xi Zhu, Yaakov Stern, and Seonjoo Lee from Columbia University. Funding came from grants provided by the National Institutes of Health and a Brain & Behavior Research Foundation NARSAD Young Investigator Grant.