A new study from the University of California, Irvine has found that aging affects the shape of our brains in ways that can be measured—and these changes may help explain memory loss and other cognitive problems as we get older.
Instead of looking only at the size or volume of certain brain areas, the research team used a new method to study how the brain’s shape changes over time. They found that the overall structure of the brain shifts in specific ways with age, and these changes are linked to thinking and memory abilities.
The study, published in the journal Nature Communications, was led by researchers from UC Irvine’s Center for the Neurobiology of Learning and Memory (CNLM). They analyzed over 2,600 brain scans from adults aged 30 to 97.
They discovered that as people age, certain parts of the brain expand outward—mostly in the lower front regions—while other parts, like the upper back regions, shrink inward. These uneven shape changes were especially noticeable in people showing signs of cognitive decline, such as memory or reasoning problems.
One interesting finding was that people whose brains had more shrinkage in the back part tended to do worse on reasoning tests. These shape changes were seen again in two other independent sets of brain scans, which shows that the results are consistent and reliable.
A key area affected by these shape changes is the entorhinal cortex. This small part of the brain plays a big role in memory. It’s also one of the first places where a harmful protein called tau builds up in people with Alzheimer’s disease.
The study suggests that, over time, the shifting shape of the brain may push the entorhinal cortex closer to the base of the skull. This could put pressure on the area and make it more vulnerable to damage. Until now, researchers hadn’t considered that physical pressure from brain shape changes could be a cause of Alzheimer’s disease.
According to Dr. Michael Yassa, co-author of the study and director of the CNLM, this idea might help explain why the entorhinal cortex is often one of the first places to show damage in Alzheimer’s. He said that understanding how brain shape shifts might help scientists find new ways to detect the disease early—possibly even before symptoms appear.
This new method of studying the brain’s geometry could become a powerful tool for spotting early warning signs of dementia and other age-related brain conditions. It’s part of a bigger effort by scientists to understand how and why the brain becomes more vulnerable with age.
Dr. Niels Janssen, another lead author, explained that this research is about more than just brain shrinkage. It’s about how the brain’s shape changes, and how those changes can predict who might have problems with memory or thinking later on.
The study was done in partnership with researchers from the Universidad de La Laguna in Spain and involved many scientists, including co-first authors Yuritza Escalante and Dr. Jenna Adams. It also shows how working across countries can help tackle big health challenges, like Alzheimer’s disease.
Dr. Yassa summed it up best: “We’re just beginning to understand how brain shape affects disease. But this research shows that the answers may be right in front of us—in the shape of the brain itself.”
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