One of the most puzzling aspects of Alzheimer’s disease is why it affects people so differently. Some develop memory loss and dementia as Alzheimer’s progresses while others show little or no cognitive decline despite having the same underlying brain pathology. It is estimated that about thirty percent of older adults who develop Alzheimer’s disease never experience its symptoms, and scientists still aren’t sure why. An understanding of this could lead to new ways to treat or even prevent dementia.
Research from the Netherlands Institute for Neuroscience (published in 2026*) suggests that the answer may lie in how a rare group of brain cells, called immature neurons, responds to damage. These findings offer new insight into cognitive resilience, the brain’s ability to continue functioning despite disease. This idea focuses on adult neurogenesis, the process through which new neurons are generated in the adult brain. The researchers examined brain tissue samples from healthy individuals, people with Alzheimer’s disease, and people whose brains showed Alzheimer’s pathology even though they never developed dementia.
They found immature neurons in all three groups, even in the brains of people over the age of 80. In resilient individuals, these cells appeared to activate programs that helped them survive and cope with damage, suggesting that these immature neurons may do more than simply replace cells lost during disease. Researchers think it is possible that these cells support the surrounding tissue and help the brain stay functional and youthful.
A direction for future research is to explore how immature neurons communicate with other brain cells and whether those interactions help preserve memory and cognitive function. This study does not explain why those immature cells behave differently in resilient individuals than in people who develop dementia, but it does reflect a shift in Alzheimer’s research. Instead of studying how this disease damages the brain, scientists are asking why some brains can withstand that damage.
*Tosoni, G., et al. Transcriptional profiles of immature neurons in aged human hippocampus track Alzheimer’s pathology and cognitive resilience. Cell Stem Cell, 2026; 33 (5): 763 DOI: 10.1016/j.stem.2026.04.002