The brain forms according to a unique principle - new discovery

Scientists have established that the human and animal brain develops from two independent populations of progenitor cells that form during early embryonic development. The first group forms the forebrain and midbrain, the second forms the hindbrain. The study, published in Nature, was conducted on mice and confirmed using human stem cells. The division was found in monkeys, chickens, zebrafish, and acorn worms, indicating an ancient origin of the mechanism.

Scientists have established that the brain of humans and other animals develops from two independent populations of progenitor cells that form during early embryonic development. The study, published in the journal Nature, showed that during gastrulation, two separate groups of cells are established. The first, called the anterior neuroectoderm, becomes the source of the forebrain and midbrain. The second, the posterior neuroectoderm, forms the hindbrain. Thus, different brain regions initially have distinct cellular origins, rather than separating later from a single set of progenitor cells. After experiments on mice, researchers confirmed the mechanism using human pluripotent stem cells. Scientists were able to direct their development along two scenarios: some cells acquired characteristics of the forebrain and midbrain, others of the hindbrain. Notably, the possibility of obtaining motor neurons of the hindbrain from stem cells was highlighted, which was previously challenging. The two cell groups differ in genetic programs: forebrain and midbrain cells activate the Otx2 gene, while future hindbrain cells activate Gbx2. A similar division was found in monkeys, chickens, zebrafish, and acorn worms, whose evolutionary lineages diverged about 550 million years ago, indicating an ancient origin of the scheme. Researchers emphasize that the results do not mean the brain once consisted of two separate organs — the modern brain is a single organ formed from two ancient lineages of progenitor cells.