Immature brain cells behave differently in resilient Alzheimer’s brains
Some people remain mentally sharp even when their brains show clear signs of Alzheimer’s disease. Researchers in the Netherlands may have found a clue hidden in a rare group of cells that normally go unnoticed.
Scientists at the Netherlands Institute for Neuroscience examined donated brain tissue collected through the Netherlands Brain Bank. They compared three groups: people without detectable brain pathology, patients who had developed dementia, and individuals whose brains showed Alzheimer’s changes but who had remained cognitively healthy. That last group exhibits what researchers call cognitive resilience: the ability to stay mentally stable despite brain damage.
The team searched for immature neurons (nerve cells that have not yet fully matured) in a small region within the brain’s memory center. “These cells are extremely rare, so we had to develop new ways to find them,” says senior author Evgenia Salta. They found them in all three groups, including in brains of people averaging over 80 years of age.
Not the number, but the behavior
The surprise was that the cognitively resilient group did not have more immature neurons than people with dementia. The difference lay in how those cells responded to disease. In resilient brains, the immature neurons showed signs of processes associated with survival and protection against damage. Signals related to inflammation and cell death were lower. Persistent inflammation in the brain can disrupt connections between neurons; these cells appeared better equipped to withstand that.
Cautious about conclusions
Salta stresses that the researchers have not established what these immature neurons actually do. “We assume the cells’ function based on the data, but we cannot confirm it in this type of study,” she explains. The findings are based on patterns observed in brain tissue, not direct experiments. It also remains unclear whether the presence of these cells means the aging human brain continues to produce new neurons. That remains an open scientific debate.
“This is one piece of a very large puzzle,” Salta concludes. “There will never be just one factor that explains resilience.” Follow-up research will examine how these immature cells communicate with neighboring brain cells.
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