Some people remain mentally sharp despite having the brain changes of Alzheimer's disease — and a new study suggests the secret may lie in a rare group of immature brain cells that survive and support surrounding tissue instead of succumbing to damage.
The research
Researchers at the Netherlands Institute for Neuroscience — part of the Royal Netherlands Academy of Arts and Sciences (KNAW) — examined donated brain tissue from the Netherlands Brain Bank. The study, led by senior author Evgenia Salta, compared three groups: healthy individuals, people diagnosed with Alzheimer's disease, and people who had Alzheimer's pathology in their brains but never developed dementia (often called "resilient" individuals).
The team focused on a small region within the brain's memory center — one of the few places where adult neurogenesis, the birth of new neurons, may still occur in humans. Because the target cells are extremely rare, the researchers developed new analytical methods tailored specifically to human tissue, reducing reliance on animal models.
They found that immature neurons — young cells that haven't yet fully matured — were present in all groups, even in people whose average age was over 80. But the surprising part was not the number of cells. Resilient brains did not have dramatically more immature neurons than Alzheimer's-affected brains.
Instead, the key difference was in how the cells behaved. In resilient individuals, the immature neurons appeared to activate programs that help them survive and cope with damage. These brains also showed lower signals related to inflammation and cell death.
"In resilient individuals, these cells seem to activate programs that help them survive and cope with damage," Salta said. "We also see lower signals related to inflammation and cell death."
Salta noted that around 30 percent of older adults who develop Alzheimer's disease never experience its symptoms — a mystery that motivated the study. She cautioned that because the research used donated tissue, the team cannot directly observe how these cells function in living brains, and that resilience is unlikely to have a single explanation. "This is one piece of a very large puzzle," she said.
Why it matters
This study shifts attention from simply counting neurons to understanding how brain cells communicate, survive, and manage inflammation. If immature neurons act as a kind of "fertilizer" for a degenerating network — supporting surrounding tissue and keeping the brain functional — that could open entirely new avenues for protecting memory as we age. For anyone curious about their own cognition, the takeaway is that brain health isn't only about how many cells you have, but about the environment you create for them. Chronic inflammation and cell stress are factors you can influence through lifestyle choices, even if you can't change your genetics.
What you can do
- Keep learning challenging new skills — it supports neuroplasticity and may help maintain cognitive reserve.
- Prioritize sleep, since it helps clear inflammatory waste products from the brain.
- Stay physically active; exercise is linked to lower inflammation and better brain health.
- Eat a Mediterranean-style diet rich in anti-inflammatory foods.
- Manage chronic stress, which can raise inflammation over time.
Source: ScienceDaily Mind & Brain
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