Super Neurons of superstars
Large neurons turned out to be a marker of successful aging
Alexandra Medvedeva, Naked Science
Studying the brains of elderly people with good memory, scientists from Northwestern University (USA) found that the neurons in their entorhinal cortex (the area of the brain responsible for memory) are much larger than those of peers with average cognitive abilities and even in people 20-30 years younger. The results of the study are published in The Journal of Neuroscience (Nassif et al., Integrity of neuronal size in the entorhinal cortex is a biological substrate of exceptional cognitive aging).
In addition, these large neurons did not contain tangles of tau protein, which accumulate in cells with various cognitive impairments associated with age, including Alzheimer's disease. According to the authors, this may mean that large neurons were originally present in the cortex of centenarians and structurally preserved throughout life. Probably, such cells represent a marker of "super-aging".
The study was conducted within the framework of the SuperAging program, which involves unique people known as "SuperAgers" ("superstars") who lived to 80 years and retained exceptional memory — at least as good as people aged 50-60 years. To understand what caused these features, and to understand why "superstars" are resistant to the development of Alzheimer's disease, the authors posthumously studied the brains of six centenarians who bequeathed the body to science.
Scientists have especially focused on the entorhinal cortex of the brain. It is located in the temporal lobe and belongs to the hippocampal formation, participates in memory processes and is the first to suffer from Alzheimer's disease. This cortex consists of six layers of neurons arranged on top of each other. In particular, the second layer receives information from other memory centers and serves as a very specific and important center of the brain's memory chain.
It turned out that the "superstar" second layer of the entorhinal cortex contained larger and healthier neurons compared to their peers, patients with early-stage Alzheimer's disease and even people 20-30 years younger than centenarians. The researchers also showed that these large neurons of the second layer are spared from the formation of tangles of tau, which, on the contrary, lead to a decrease in the size of neurons.
For still unknown reasons, neurons in the entorhinal cortex are selectively susceptible to the formation of tangles of tau protein both during normal aging and in the early stages of Alzheimer's disease. However, the neurons of the "superstars" practically did not contain such structures. Now scientists plan to continue their research to understand what determines the size and integrity of the neurons of centenarians.
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