Khaberni - An analysis of more than 10,000 MRI scans showed that memory loss with age reflects a weakness in entire neural networks, not just one region or gene.
A comprehensive international study involving more than 10,000 MRI scans and over 13,000 memory tests on 3700 cognitively healthy adults from 13 independent projects found that age-related memory loss is linked to widespread structural changes in several brain regions.
The analysis showed that brain volume loss and memory decline are non-linearly related; as long as structural changes remain moderate, memory can be maintained at a stable level. However, with an increase in the rate of atrophy, cognitive decline disproportionately increases and progresses faster, especially in old age.
As researchers expected, the strongest connections were in the hippocampus, the key area for forming and retaining memories, but the changes are not confined to this area. Significant correlations were found in many cortical and deep brain structures, indicating that the impairment affects the entire neural networks. Thus, memory weakness reflects not just the failure of one area, but the overall condition of the brain.
The researchers confirmed that the patterns identified cannot only be explained by known genetic risk factors for Alzheimer's disease, such as the APOE ε4 variant, as individuals without these genetic traits also exhibited structural changes accompanied by memory impairment.
This suggests that normal brain aging cannot be reduced to a simple model defining "one gene or one disease"; age-related memory loss reflects the accumulated biological deterioration of the brain over decades. The hippocampus plays a significant role, but it is part of a broader network that includes the entire brain.
