If the memory center of the human brain can grow new cells , it could help people recover from depression, post-traumatic stress disorder, delay the onset of Alzheimer’s disease, deepen our understanding of epilepsy, and offer new insights about memory and learning.
For decades, scientists have debated whether the birth of new neurons, called neurogenesis, is possible in an area of the brain responsible for learning, memory, and mood regulation. Now a new study published in the journal Nature Medicine tips the balance to “yes.” According to the study, a specific region of the human brain – known as the dentate gyrus – produces new neurons up to the age of 90; lifetime.
The researchers, led by María Llorens-Martín, a scientist at the Severo Ochoa Molecular Biology Center (Spain), tested a variety of methods to preserve the brain tissue of 58 recently deceased people. They found that different preservation methods led to different conclusions about whether new neurons could develop in the adult and aging brain.
Llorens-Martin, lead author of the paper, must preserve brain tissue within a few hours after death and be very precise with the specific chemicals used to preserve the tissue or proteins that identify developing cells.
She said she began carefully collecting and preserving brain samples in 2010, when she realized that many brains stored in brain banks were not being properly preserved for this type of research . In her study, she and her colleagues examined the brains of people who died with their memories intact, and those who died at different stages of Alzheimer’s disease. It found that the brains of people with Alzheimer’s showed few if any signs of new neurons in the hippocampus, with fewer signs as they progressed through the disease. This suggests that the loss of new neurons, if it could be detected in the living brain, would be an early indicator of the onset of Alzheimer’s disease, and that promoting new neuronal growth could delay or prevent the disease that now affects millions of people. around the world.
Neurogenesis
Neurogenesis in the hippocampus is important because evidence in animals shows that it is essential for pattern separation. In people, the inability to distinguish between two similar events could explain why PTSD patients continue to relive the same experiences, even though their circumstances have changed. Furthermore, many deficits seen in the early stages of cognitive decline are similar to those seen in animals whose neurogenesis has stopped.
Researchers can stimulate the growth of new neurons in mice and rats by making rodents exercise more or by providing environments that are more cognitively or socially stimulating, Llorens-Martin says. “This could not be applied to advanced Alzheimer’s disease stages. B ut if we could act at an earlier stage where mobility is not compromised, who knows, maybe we could turn slow down or prevent the loss of plasticity the brain “, concludes the expert.
And he ends: “ There is still a long way to go to apply these results to the treatment of human beings, but the results obtained are encouraging as they show the existence of a dynamic population of cells that in other mammalian species have been shown to be important for regulation of the memory”.
Referencia: E. P. Moreno-Jiménez*, M. Flor-García*, J. Terreros-Roncal*, A. Rábano, F. Cafini, N. Pallas-Bazarra, J. Ávila and M. Llorens-Martín. Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer’s disease. Nature Medicine. DOI: 10.1038/s41591-019-0375-9
