Memory center ages through DNA reorganization
The brain’s memory hub, the hippocampus, changes with age not only in activity but in how its DNA is physically organized. A new study maps those changes in detail and links them to cognitive decline.
DNA inside every cell nucleus is tightly folded. The three-dimensional structure of that folding partly determines which genes are switched on or off. With aging, that structure shifts, and so does gene activity. That this occurs in the human brain has now been examined in detail for the first time in human hippocampal tissue.
The study, published in Science, combined two techniques: epigenetic profiling (measuring chemical modifications on DNA) and 3D genome mapping (measuring how DNA regions make spatial contact with each other). Together, they reveal how the spatial organization of the genome in the hippocampus shifts as people age.
Genes supporting memory become less accessible
The researchers found that DNA regions involved in synaptic function (the connections between brain cells) become less accessible with age. At the same time, the spatial contacts between DNA regions shift, suggesting that gene regulation in the aging hippocampus is structurally altered. These are associations, not proven causal pathways. Whether these changes cause cognitive decline or result from it has not been established.
What the study adds is precision. It was previously known that epigenetic changes occur in the aging brain. Now it is apparent that such changes coincide with reorganization of three-dimensional genome structure, specifically in a brain region strongly linked to age-related memory problems.
Implications for future research
The findings are relevant to Alzheimer’s research: the hippocampus is among the first regions affected by the disease. If specific structural DNA changes precede symptoms, they might eventually serve as early markers. That remains speculative at this stage; the study presents an observational map, not an intervention. Science published this as part of a broader thematic issue on the 3D genome in health and disease.
Want to research this yourself? Search for: 3D genome organization hippocampus aging, epigenetic reprogramming neuronal aging, chromatin structure cognitive decline