If some people don’t forget the slightest thing despite their advanced age, it may be due to the large size of some vital brain cells. People over 80 who keep their memories nearly intact have “super” neurons in their brains that are significantly larger than the average of their peers but are healthier, a new American study shows for the first time.

Researchers led by Associate Professor of Psychiatry and Neuropsychology Tamar Geffen of the Northwestern University School of Medicine in Chicago, published in the Journal of Neuroscience, concluded that “larger neurons constitute the biological ‘signature’ of the superaging course” ( super aging).

Post-mortem comparative study of the brains of six people with very good memory who died on average at age 91, seven people who died on average at age 89 and had memory impairment typical for their age, six people who died at an average age of 49 people and in five people at an early stage of Alzheimer’s disease, identified in the first group, in their memory area, especially affected by dementia (entorhinal cortex), the presence of neurons was found, which are even larger than people 20-30 years younger.

It has been found that older people with excellent memory (so-called “super-aged”) have about 10% more neurons than the corresponding neurons in people who died at the same age but with worse memory. The super-old also had about 5% more neurons than those who died 40 years younger. These superneurons, in addition to being unusually large, also lack the “plaques” of toxic proteins that are a characteristic pathological feature of Alzheimer’s disease.

“The remarkable observation that these individuals have larger neurons than younger individuals may suggest that such large nerve cells were present from birth and structurally preserved throughout life,” Dr. Geffen said.

Alexandra Turutoglu, a Greek associate professor of neuroscience at Harvard Medical School who has studied “super old people” for years, told New Scientist that the new study “adds to the growing evidence that super old people are different from typical adults.” at several levels of the brain. The sample (study) is relatively small, but this is understandable. “The overage is a rare group, so it’s hard to find large numbers of them for post-mortem research on their brains.”

Scientists have been trying for years to understand why some people are immune to Alzheimer’s disease and retain excellent memories despite advancing age. The new study provides a biological explanation for why this might be the case, although the question remains why the “lucky ones” have such large and healthy neurons to such an advanced age.

Link to scientific publication: https://www.jneurosci.org/content/early/2022/09/26/JNEUROSCI.0679-22.2022

Source: RES-EMI