What is it about?
The hippocampus is a key brain region for memory and one of the first areas affected by aging and Alzheimer’s disease. Using advanced MRI methods, we measured microscopic tissue properties in the living human hippocampus over time. These “in vivo histology” scans revealed early changes in myelin, iron, and water content that occur before visible shrinkage of the brain. Our findings show that these subtle microstructural changes, especially those linked to Alzheimer’s-related proteins, provide an earlier and more detailed picture of brain health than traditional MRI measures.
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Why is it important?
This work provides the most detailed map to date of how the hippocampus changes with age and early Alzheimer’s disease, combining multiple MRI measures to separate different biological processes. By linking these changes to Alzheimer’s-related proteins and genetic risk, this study shows that microstructural MRI can detect signs of disease long before symptoms appear. These findings could help researchers develop earlier and more targeted strategies to preserve brain health and memory function as we age.
Perspectives
This article was a pleasure to write, and a excellent exercise in data presentation. The paper truly highlights the beauty of the hippocampus, this fascinating and extremely important brain region that is so central to disease and behaviour. It also highlights the continued value of the PREVENT-AD dataset, an invaluable resource for studying early brain changes due to Alzheimer's disease.
Alfie Wearn
McGill University
Read the Original
This page is a summary of: Quantitative MRI of the hippocampus reveals microstructural trajectories of aging and Alzheimer’s disease pathology, Proceedings of the National Academy of Sciences, October 2025, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2502674122.
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