This is what neurologists know about the brains of these seniors who age without losing any of their cognitive faculties

This is what neurologists know about the brains of these seniors who age without losing any of their cognitive faculties
This is what neurologists know about the brains of these seniors who age without losing any of their cognitive faculties

Considering the overall weakening of cognitive abilities with age as inevitable is in fact a bit simplistic.

Atlantico: Forgetting, confused thoughts… Very often, cognition deteriorates as we age. However, certain individuals called the “super-aged” mysteriously seem to struggle more easily against the ravages of time. Who are these “super-elders”? Are there any significant differences in their lifestyle or habits compared to other people their age?

André Nieoullon: Considering the overall weakening of cognitive abilities with age as inevitable is in fact a bit simplistic. For at least two reasons. Firstly because if indeed certain aspects of cognition are clearly sensitive to aging such that this can be understood by measuring cognitive abilities in relation to the speed of processing the information necessary for reasoning, what we call “working memory” particularly important for the realization of so-called “executive” functions, or what is referred to as “episodic memory”, other aspects of cognitive functions seem, on the contrary, not to be significantly affected with advanced age; such as verbal skills, so-called “procedural” skills or even semantic memory, in relation to the meaning of words, or even skills linked to mental calculation, for illustration. Then, and this is the second reason why it is, from my point of view, too simplistic to consider the weakening of cognitive abilities with age as inevitable, because not all individuals are affected in the same way. It is in this context that the concept that you evoke of these “super-aged” people appeared who, according to the latest studies, present around the age of 80 cognitive capacities equivalent to those of individuals with 20 to 30 years of age. less, which could represent around 5% of the population of elderly people exempt from neurological and psychiatric disorders.

For several decades, numerous studies have been devoted to them as the cognitive abilities of these individuals are remarkable, leading to the conclusion that, if the skills linked to knowledge and acquired experience are, in general, rather maintained with age, those related to reasoning abilities are particularly preserved in these “super-elders”. All of the work aims to understand what could explain the remarkable resistance to advancing age of these people compared to others. At this stage, the question remains open and it turns out that a priori neither the way of life, diet or education is able to really account for this particular resistance to the effects of time, except perhaps these subjects present particularly developed social relationships and very preserved physical activity, and present damage to their mental health assessed in terms of anxiety and depression that is much less than that of subjects showing “normal” cognitive functions in relation to their age. But, at this stage, nothing definitive has been achieved and studies are continuing on the one hand at the genetic level, on the other hand by questioning possible characteristics of cerebral organization.

A study published in the Journal of Neuroscience helps shed light on what makes super-elders so special, highlighting differences in the structure of their brains. What are we talking about ? What are these differences due to?

You are referring to a recent study by a group of Spanish researchers, who studied the cerebral organization of these “super-aged” people using MRI, to find out if the structure of the brain itself was rather preserved compared to that of individuals presenting aging considered “normal”. Overall, the main result of this study is to show that, if we are interested in the evolution of the structure of the brain over a follow-up of 5 years from the age of 75, the structural modifications apprehended in terms of volume of gray matter and white matter were characterized by a form of brain preservation over time in the “super-aged” while the other subjects saw their brain volume significantly altered during this same period of time. These data were linked to the particular cognitive abilities of “super-aged” individuals.

Interestingly, however, when researchers are more particularly interested in the white matter, which represents the bundles of fibers connecting the different brain regions together, it turns out that these brain connections appear particularly preserved in the areas represented by the anterior brain, what we call on the one hand the frontal lobe involved in cognitive functions or the cingulate gyrus, without major differences in the regions contributing to memory and attentional processes, in particular the hippocampus, in relation to what It is generally considered that these structures are more sensitive to aging than the rest of the brain. However, other studies focused this time on the study of the gray matter, where the neurons are located, tend to show that on the contrary there is in the “super-aged” a relative preservation in these regions involved in the memory processes, suggesting better control of these processes from the prefrontal cortex. But, at this stage, no explanatory elements are provided on the origin of these structural preservations of the brain in relation to advancing age.

Are there reflexes to adopt to “preserve” our brain as we age?

From the moment when no determining factor of these mechanisms could be identified in terms of demographic factors, lifestyle or even genetics (at this stage) to account for the particular cognitive performances of the “super-aged” , it is difficult to propose recipes likely to attenuate the effects of aging on behavior. We will therefore stick to the usual considerations according to which a healthy lifestyle, including diets designed to reduce the effects of obesity or even diabetes and cardiovascular diseases, as well as regular physical activity and sustained, with the maintenance of strong social relationships, clearly have a positive effect on the consequences of aging.

Most research on aging and memory focuses on people who develop dementia in their later years of life. Should research focus more on studying healthy aging individuals?

Basically, you are right, but one does not exclude the other. In terms of public health, priority is legitimately given to research on Alzheimer’s disease given the burden that dementia represents for our society. But it is interesting to note, which is noted by several studies, that the “super-elderly” are, it seems, less likely to develop Alzheimer’s disease than their less cognitively favored peers. This is perhaps a direction of research in which we should invest in trying to understand why these individuals are particularly resistant to the onset of dementia.

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