The brain is also renewed in mature age: confirmation from a Swedish study that opens new perspectives

The adult human brain is not a fixed and immutable structure: it continues to generate new neurons even beyond youth. To demonstrate it, with more solid data than ever and the help of algorithms of Machine Learningis a study by Karolinska Institutet In Sweden, recently published in the magazine Cell Stem Cell. This research represents a crucial step forward in the debate, which lasted decades and with conflicting positions by experts, on the possibility of neurogenesis in the adult hippocampusa key brain region for functions such as memory and learning but also for the regulation of mood. And therefore, it is clear without too much difficulty, even for crucial pathologies such as Alzheimer’s disease.

For many years the scientific community has in fact been divided on the matter. Some studies had indicated the presence of new neurons in the adult brain but others had not been able to confirm these resultsraising doubts about the real existence of this phenomenon in the human being. With the research conducted by the Swedish team, however, more convincing tests come thanks to a combination of genetic techniques and analysis on human brain fabrics of teenagers and adults.

A new approach

The group led by Jonas Frisénprofessor at the Department of Cell and Molecular Biology of the Karolinska Institutet, used an innovative method based on DNA Barcoding. This approach allows you to trace the cell descent into the brain tissueidentifying which cells derive from common progenitors. In practice, it was possible to see If new nerve cells of subjects between 0 and 78 years with data taken from different international biobes had actually generated progenitor cells in the hippocampus of adult individuals.

“We analyzed the human hippocampus from birth to adulthood using the Single nucleus sequencing – reads the study – We have identified all the phases of neural progenitor cells in early childhood. In adults, using antibodies against the Ki67 proliferation marker and automatic learning algorithms, we have identified neural pro -themal progenitor cells. In addition, the transcriptomic data showed that neural progenitor cells were located inside the tooth. The results contribute to understanding neurogenesis in adult human beings ». The sequencing of the single nucleus AR is a technique that allows you to analyze the gene expression in terms of single cell nucleus, a methodology is particularly useful when working with fabrics that are difficult to dissociate or when you want to avoid induction of changes in gene expression due to cell dissociation.

Thanks to this sophisticated method, reconstructing a kind of genealogical tree of neurons, the researchers managed to identify different phases of neuronal development, from stem cells to immature neurons, many of which were in the division phase. To locate these cells they have used two techniques that allow you to identify where, inside the tissue, the different genes are active: Rnascope and Xenium. These methods confirmed that new training cells were located in a specific area of the hippocampus called giropart of the hippocampus located in the most medial part of the cerebral cortex. These cells they shared the same genetic codeunequivocal sign that had developed from the same progenitor cell. A genetic evidence confirms that Adult neurogenesis is also a reality in mannot only in laboratory animals such as pigs, rats and monkeys where the phenomenon had already been observed and confirmed.

How the perspective changes

The discovery naturally has very large implications. The formation of new neurons could play a fundamental role in memory and learning processes but also in brain response to stressful or traumatic events. In addition, understanding neurogenesis could offer new reading keys to face neurological and psychiatric disorders such as depression or neurodegenerative diseases, including Alzheimer’s.

Frisén stresses that the results of the study are encouraging also on the clinical levelbecause they indicate that The adult human brain maintains greater plasticity than you thought so far. According to the scientist, the ability to produce new neurons could one day be stimulated in a targeted waywith possible therapeutic repercussions precisely for different brain diseases.

Despite the importance of the results, Frisén specifies that they are still Further research is needed to better understand the functional meaning of these new neurons in the adult hipocampus. It remains to be clarified, for example, what theirs is specific contribution To the already existing neuronal circuits – are neurons that repair, which they replace, what feature that show off? – And if the quantity of new neurons produced can vary in relation to factors such as age, state of health or environmental conditions. In fact they emerged great variations between individuals: Some adults owned numerous neural progenitor cells while others had very few or almost none.

The study of the Karolinska Institutet still represents a significant turning point, finally providing A direct and robust test that the adult human brain never stops generating new nerve cells.

Scientific sources mentioned in this article:

Identification of proliferating neural progenors in the adult Human hippocampus