New research connects sustained neurogenesis and epigenetic regulation with preserved memory in aging and resistance to Alzheimer’s.
A long-running question in neuroscience – whether the adult human brain continues to generate new neurons – has tended to produce more heat than light. Now, a new study drawing on postmortem human hippocampal tissue offers a more constructive direction, moving beyond existence to mechanism. By combining single-nucleus RNA sequencing with chromatin accessibility profiling (a method of identifying the brain’s active ‘genetic switches’), researchers have mapped the molecular landscape of neurogenesis across aging, cognitive decline and exceptional cognitive performance [1].
The findings point to a gradient rather than a binary state. Neurogenesis appears to persist into later life; it falters in Alzheimer’s disease but in a small but revealing group of “SuperAgers”, it remains unusually robust. These individuals, aged over 80 yet performing on memory tests at levels comparable to those decades younger, appear to generate substantially more new neurons than their peers, alongside maintaining a distinct molecular profile associated with resilience [1].
Longevity.Technology: For a field that has spent years arguing over whether adult human neurogenesis is real, this study does something far more useful – it begins to show why it matters. The headline finding, that SuperAgers appear to generate roughly twice as many new hippocampal neurons as their cognitively normal age-matched peers, is striking enough; more interesting still is the suggestion that what protects memory into very old age may not be a vague notion of “brain maintenance” but a distinct, regulated and potentially targetable biology of resilience. The paper’s emphasis on chromatin accessibility is especially telling – the earliest changes seem to occur not simply at the level of gene expression, but in the epigenetic architecture that governs which regenerative programs remain available and which are quietly shut down with age and disease. That matters because it nudges the conversation away from the rather fatalistic idea of cognitive aging as an inevitable neuronal dwindling, and toward a more provocative possibility: that some brains retain a younger, more plastic operating system well into later life. If so, SuperAgers may be less a biological curiosity than a preview – albeit an early one – of what brain healthspan interventions might one day try to preserve, or even restore.
Mapping neurogenesis across the lifespan
The study analyzed nearly 356,000 nuclei from human hippocampi spanning five groups – young adults, cognitively healthy older adults, individuals with preclinical pathology, those with Alzheimer’s disease and SuperAgers [1]. This allowed the authors to identify distinct stages of the neurogenic trajectory, from neural stem cells through neuroblasts to immature neurons and ultimately mature granule cells.
“Using multiomic single-cell sequencing… we identified neural stem cells, neuroblasts and immature granule neurons,” the authors write, adding that these populations form a continuous developmental pathway within the adult hippocampus [1].
What changes with age is not simply the presence of these cells, but their behavior. In Alzheimer’s disease, the number of immature neurons is reduced, while neural stem cells may accumulate without successfully progressing through the differentiation pipeline. It is less a failure of supply than of completion – a stalled assembly line rather than an empty factory.
Epigenetic drift and early vulnerability
One of the more revealing aspects of the work lies in its focus on chromatin accessibility. Differences between groups were more pronounced at the level of open chromatin regions than gene expression, suggesting that epigenetic regulation plays a central role in determining neurogenic capacity.
The authors note that “the majority of age-driven and diagnosis-driven alterations in neurogenesis were observed in the number of [differentially accessible regions] compared with [genes]”, pointing to chromatin state as a more stable indicator of cognitive trajectory [1].
Crucially, these changes are detectable in preclinical stages. Alterations in chromatin accessibility appear before overt cognitive impairment, hinting at a window in which intervention might still redirect the trajectory. Subtle shifts. Early signals.
SuperAgers and the biology of resilience
Within this framework, SuperAgers offer a useful contrast. Their hippocampi show increased numbers of immature neurons and neuroblasts, alongside a distinct regulatory landscape – what the authors describe as a “resilience signature” that preserves neurogenic function despite chronological age [1].
“We’ve always said that SuperAgers show that the aging brain can be biologically active, adaptable, flexible, but we didn’t know why,” said Tamar Gefen, coauthor of the paper and associate professor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine and a neuropsychologist at Northwestern’s Mesulam Institute for Cognitive Neurology and Alzheimer’s Disease. “This is biological proof that their brains are more plastic, and a real discovery that shows that neurogenesis of young neurons in the hippocampus may be a contributing factor [2].”
This plasticity appears to extend beyond neuron production. The study also highlights the role of astrocytes and CA1 neurons in maintaining cognitive integrity, with gene regulatory programs supporting synaptic function and communication remaining active in SuperAgers but diminished in Alzheimer’s disease [1].
“What’s emerging from this study is this idea that SuperAgers are, in general, very distinct,” said Changiz Geula, research professor at the Mesulam Institute. “The genetic programs that support brain cell survival and communication stay on in SuperAgers in these cells, but they’re switched off in Alzheimer’s disease [2].”
From mechanism to intervention
If the biology is complex, the translational implications are nonetheless clear. The pathways implicated – synaptic plasticity, neuronal development, epigenetic regulation – offer multiple points of entry for therapeutic exploration. Targeting chromatin accessibility, modulating transcription factor networks or preserving synaptic signaling could, in principle, help sustain neurogenesis or prevent its decline.
“Determining why some brains age more healthily than others can help researchers make therapeutics for healthy aging, cognitive resilience and the prevention of Alzheimer’s disease and related dementia,” said correspondng author Orly Lazarov, professor in the University of Illinois College of Medicine and director of UIC’s Alzheimer’s Disease and Related Dementia Training Program. [2].
Still, caution is warranted. The study is based on postmortem tissue, with inherent variability and limited sample sizes; it describes associations rather than causation. Even so, it refines the map – and maps tend to matter.
A shifting baseline
Perhaps the more subtle implication lies in how we think about aging itself. If neurogenesis persists, if it can be sustained, if it varies so markedly between individuals, then cognitive decline begins to look less like a fixed endpoint and more like a contingent outcome – shaped by regulatory networks, cellular environments and time.
Not inevitable. Not uniform.
And, increasingly, not beyond influence.
Main photo shows a donated SuperAger brain. (All photos credit: Shane Collins, Northwestern University)
[1] https://www.nature.com/articles/s41586-026-10169-4
[2] https://news.northwestern.edu/stories/2026/02/as-superagers-age-they-make-at-least-twice-as-many-new-neurons-as-their-peers
