As we grow older, our brains don’t just shrink—they actually change shape in noticeable ways.
A new study led by researchers from the University of California, Irvine’s Center for the Neurobiology of Learning and Memory has found that these changes in brain shape are closely linked to how well we think, remember, and reason as we age.
The research team, which included international collaborators, didn’t just focus on the size of brain areas as most previous studies have done. Instead, they used a new technique to look at how the entire shape of the brain changes over time. Their findings show that these shape shifts can be strong indicators of brain health.
The study, published in the journal Nature Communications, was supported by the National Institute on Aging. It looked at more than 2,600 brain scans from adults aged between 30 and 97 years.
What the scientists found was surprising: the bottom front parts of the brain tend to expand outward, while the top back parts shrink inward. These uneven changes in shape were especially clear in older people who had problems with thinking and memory.
For example, people who showed more inward shrinking at the back of the brain often had trouble with reasoning skills. This suggests that how the brain bends and stretches could be linked directly to how it works. What’s more, these same results were found in two different sets of brain scans, which makes the findings more trustworthy.
One especially important area affected by shape changes is the entorhinal cortex. This is a small region deep in the brain that helps us store and retrieve memories. Scientists already know that this area is one of the first to be affected in Alzheimer’s disease, where a harmful protein called tau builds up.
The new study suggests that as the brain changes shape with age, this region may get pushed closer to the hard bottom part of the skull. That pressure could make it more likely to become damaged.
According to Dr. Michael Yassa, one of the study’s authors, this could explain why the entorhinal cortex is often the first area affected in Alzheimer’s.
If the brain’s shape is slowly shifting in a way that puts physical stress on this sensitive area, it may help trigger the disease. Understanding this could lead to new ways to detect Alzheimer’s earlier and possibly even prevent it.
The researchers believe their method of studying brain shape could be used in the future to spot people at risk of dementia before they show any signs. This could lead to earlier treatments and better outcomes.
Dr. Niels Janssen, another senior author of the study, explained that this work isn’t just about seeing which parts of the brain are smaller. It’s about understanding how the whole structure of the brain reacts to aging, and how that structure can predict who might have problems with memory and thinking in the future.
This study was made possible by a strong partnership between researchers in the United States and Spain, showing the power of global collaboration in solving major health challenges.
The findings open a new path in brain research. As Dr. Yassa put it, the shape of the brain might hold clues that have been right in front of us all along. Now, scientists are starting to look at those clues more closely to better understand brain aging and disease.
If you care about dementia, please read studies about Early heart rhythm problem linked to higher dementia risk and findings of Green leafy vegetables may help reduce Alzheimer’s risk.
For more about dementia, please read studies about Research shows an important cause of frontotemporal dementia and findings of New way to detect Lewy body disease early, a leading cause of dementia.
The study is published in Nature Communications.
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