Study: Human brain consists of two separate organs

Lled by scientists at Stanford University Medical School in the United States, the new investigation “shows that the human brain consists of two intelligently combined old nervous systems,” states a university statement.

One of the “most primitive” parts is responsible for vital functions, such as heart rate, breathing, blood pressure or sleep, while the other “makes us distinctly human, capable of poetry, mathematics and questioning our origins”, he says.

“ We first demonstrated that the frontal part of the brain originates in a parent cell that is totally different from the posterior part,” said Kyle Loh, an associate professor of University Development Biology and one of the authors of the study published today in Nature Neuroscience.

“ Our discovery means that we can now cultivate neurons from the back of the brain, the Rombencephalus [often called the brainstem], on a Petri plate and study its functions,” he added, quoted in the statement.

And this opens up new paths for the study of diseases that affect the brain stem, such as severe degenerative spinal muscle atrophy (AME) and amyotrophic lateral sclerosis (ELA or Lou Gehrig disease).

The study, which has Kyle Loh as senior author and graduate students Carolyn Dundes and Rayyan Jokhai as first co-authors, analyzes the early moments of embryonic development of rats, which allowed the identification of “two different brain progenitor cells”.

One of them “is destined to become the prosencephalus [read with the thought of higher level - language, consciousness and abstract reasoning] and the mesencephalus”, two of the three main regions of the brain, besides the Rombencephalus, whose formation is linked to that of the other progenitor cell.

According to the statement, “these two cell populations never overlap” and “are mutually exclusive since the early stages of development”.

Jokhai and Dundes discovered that the Rombencephalus follows a separate path of development, running parallel (instead of branching) to what creates the prosencephalus and the midbrain.

“ Previous attempts to create Rombencephalus neurons probably tried to transform progenitors of the prosencephalus and mesencephalus into Rombencephalus cells, which our study shows is not possible,” Jokhai explained, quoted in the statement.

After the discovery, scientists were able, for the first time, to “induce human pluripotent stem cells (a type of cell capable of creating any of the human body) to become functional Rombenbrain motor neurons in the laboratory.”.

So far, studying diseases such as AME and ALS was almost impossible because scientists could not obtain brain stem tissue from living patients, but the ability to cultivate those neurons in the laboratory opens up new possibilities to understand what goes wrong.

The treatment of obesity can also benefit, since the Rombencephalus contains circuits that regulate hunger, thus the medicines for weight loss, such as semiglutide, also used to treat type 2 diabetes and sold under the brand Ozempic.

“ We now have a model to better understand these devastating diseases and work on the development of regenerative therapies for them,” Jokhai said, adding that this “is a very exciting new frontier in brain research.”.