Some brains age better than others
As we age, the neurons in our brain deteriorate, which can lead to the loss of certain cognitive abilities, such as memory. However, the brains of some seniors seem to escape it. According to a recent study, the size of neurons in the brains of “ super-seniors ” who retain good memories are larger than average.
“ Super-seniors ” (in English, SuperAgers) are people aged 80 and over whose memory capacity is not only above the average of “normal” seniors, but as good as that of adults 20 to 30 years younger.
This “ super-power ” would be attributable to larger neurons. This is the main conclusion of the study conducted by the team of Tamar Gefen, assistant professor in the department of psychiatry and behavioral sciences at Northwestern University, in the United States.
To reach this conclusion, Professor Gefen's team conducted autopsies on the brains of six “super-elders” whose average age was 91 at the time of death. The researchers were interested in a very specific area of their brain: the entorhinal cortex. This area is responsible for episodic memory, the one that helps recall past events.
For comparison, the team also conducted autopsies on the entorhinal cortex of the brains of three other groups  ;: seven “normal seniors”, six adults between the ages of 26 and 61 with no cognitive impairment at the time of death, and five people with memory impairment diagnosed during their lifetime.
The results show that the average size of neurons in the entorhinal cortex of the “super-elders” is higher than that of the other groups. About 10% higher than that of “normal seniors” and 5% higher than that of adults aged 26 and 61 according to this New Scientist article.
Furthermore, the density of neurons showing signs of degeneration in the entorhinal cortex is lower: 700 neurons per cubic millimeter in “ super-elders ” versus 1500 in “ normal elders ”.
< p>This means that the brains of “ super-elders ” seem to age better than those of other groups. However, researchers are unable to determine what explains it. Have these neurons always been larger than those of others? Do they resist the passage of time better? Is the brain of “ super-elders ” less affected by the decrease in the number of neurons?
You should know that as we age, neurons inevitably deteriorate. And the deterioration of neurons is one of the brain damage associated with Alzheimer's disease.