Full-blown Alzheimer pathology in the brains does not always bring about Alzheimer's disease, concluded scientists at Northwestern’s Cognitive Neurology and Alzheimer’s Disease Center (CNADC).
The scientists looked at the brains of eight ‘SuperAgers’ older than ninety years old, who still had superior brain performance, and discovered that most of them had the plaques and tangles of Alzheimer’s disease. These mostly result in the death of neurons, but it did not seem to harm the brain cells of these SuperAgers, who still had superior memory test results.
Changiz Geula, professor of Cognitive Neurology at the neurology center, presented the groundbreaking results at the Society for Neuroscience 2016 Annual Conference. His team found that the cells of some elderly are immune to the toxic plaques and tangles, which usually cause cell death in the hippocampus and other areas of the brain that control cognitive function.
“We are actively investigating psychosocial, biological and genetic factors associated with SuperAging. Thus far, we have identified that SuperAgers have a thicker cortex and more Von Economo neurons,” says Emily Rogalski, Director of Neuroimaging at CNADC.
Von Economo neurons or ‘Spindle neurons’ are a specific class of neurons that are larger than regular cells and allow rapid communication between the brains. These special neurons are also present in the larger brains of animal species like elephants, whales and some types of monkeys and are linked to social intelligence.
“SuperAgers have a slower rate of atrophy over time, less Alzheimer’s pathology and are less likely to have the APOE E4 gene risk factor. The APOE E4 is the gene identified as the one with the biggest impact on the development of Alzheimer,” explains Rogalski. “We expect to have new results soon regarding the potential psychological and genetic factors.”
What factors exactly cause the brains of SuperAgers to stay healthy is not entirely clear yet. Geula and his team of neurologists have started a large-scale study to investigate how these SuperAgers could avoid the potentially deadly spread of Alzheimer. Genetical factors can play a role, as well as dietary and environmental influences.