“Old age is a shipwreck“, affirmed Charles de Gaulle. With all due respect to the General, not everyone seems on the verge of sinking: old age is not always synonymous with senility. Some members of the very closed club of fourth age – octogenarians, nonagenarians, or even centenarians – defy the passage of time and retain, despite the years, amazing cognitive abilities, which rival those of their younger siblings.
To manage to maintain their brain in great shape, the “super-seniors” have a secret. And even several. Emily Rogalski, a professor at Northwestern University near Chicago, USA, is managed to discover some, which she revealed during the annual meeting of the American Association for the Advancement of Science, AAAS, held in 2018 in Austin, Texas.
More specific neurons
The first peculiarity observed in “super-seniors” is hidden in their brain. During autopsy of ten of them, Emily Rogalski resulted in a unexpected observation : among “super-seniors”, a certain type of neuron is present in greater numbers than in the others. These are von Economo neurons, also called spindle neurons, very specific brain cells that are distinguished by their slender shape, but also and above all by their scarcity in the human brain.
They are only found in three brain regions, especially in the anterior cingulate cortex, an area involved in maintaining attention and working memory, a capacity that allows both temporarily keep information, but also to manipulate it. The main reason, no doubt, of the amazing cognitive youth “super-seniors”. “This zone was thicker in these “super-seniors” than in the average fifty and sixty-year-olds “, explique Emily Rogalski.
A protein that spares some
A another secret representatives of the fourth age still as quick-witted as when they were twenty, also resides in their brains. Not in their cells, but rather in the form of a particular protein : beta-amyloid. When she accumulates between brain cells, it forms plaques that can cause a cognitive decline, and which even seem responsible for the appearance of Alzheimer’s disease.
The brains of some “super-seniors” actually also concealed this deleterious protein, but against all expectations, among them, the presence of beta-amyloid had not degraded their cognitive faculties or their ability to memorization. An unexpected discovery that should allow researchers to better understand how some manage to cope with the senile dementia and resist the Alzheimer’s disease.
Some “super-seniors” stronger than excess
To achieve such cerebral freshness in a advanced age, you might think that a healthy life is essential. And yet, even if the excesses are generally synonymous with a premature decline, for some privileged, to drink or smoke does not prevent living old and in good mental shape. “We asked them why they thought they had become “super-seniors”, how they got there, and two or three ladies happily answered us, well that’s because I take a Martini with my friends every day at five o’clock “, tells, amused, Emily Rogalski.
Keeping the line doesn’t seem to guarantee longevity either. In the elderly, a low body mass index in fact increases the risk of premature death. To live old, it seems better to have a good fork and some fat reserves.
Scientists nonetheless temper their findings. Even if they are harmless to some, the excesses do not spare the health from everyone, as Emily Rogalski explains: “It doesn’t mean that people have to take bad habits to live longer. Some people might have a genetic predisposition which allows them to better endure drinking or smoking. “
Anyway, the “super-seniors” could bring us the keys to happy old age, in full possession of our cognitive faculties. “We do quite well at lengthen our life expectancy, but our health does not keep up, and what the “super-seniors” are capable of is morea balance between these two aspects, they live long and they live well“, concludes Emily Rogalski. Nature does seem to have endowed some privileged people with brain features out of the ordinary, which spares them cognitive wreck promised by old age.