Why do we have a bigger brain? Neuroscientists reveal the mystery of cell development.

The brain is the most important organ of the human body and probably the most complex object in the universe.
During the evolution, the cortex of the human brain increased significantly, providing a structural basis for various advanced cognitive functions.
decode the development of the human brain, will provide us with a close-to-essential answer to how "human beings are human".
, in exploring the question of why the human cerebral cortex can become larger, people often focus on the gray matter regions in which neurons are concentrated.
in fact, the white matter of the cerebral cortex has also increased dramatically during evolution.
compared to rodents such as mice, the skin of the skin white matter has 3000 times the volume of white matter.
, a study published online by the leading academic journal Cell reveals an important mechanism for the human brain to expand in the white matter region during embryonic development. "This discovery could help us better understand the development of the human brain's cortex and provide a basis for exploring the pathogenesis and treatment of diseases associated with white matter damage,"
.
" lead author and co-author dr. Dr. Wei Huang.
in the cerebral cortex, white matter is the area where nerve fibers are concentrated, consisting mainly of neuroxics with myelin, which connect various regions of the brain and are essential for the normal functioning of the brain.
white matter injuries are associated with a variety of diseases, which are common in diseases caused by abnormal skin development and, in severe cases, can lead to cerebral palsy.
in white matter, oligodendrocyte plays an extremely important role.
these cells form the myelin that wraps the neuronal axons, promoting the jumping conduction of nerve signals.
they are also the largest cell types in white matter, meeting the need to increase myelin formation as white matter expands sharply.
previously, some scientific teams used mice and other animals as models to gain a basic understanding of how less protrusion cells are produced and differentiated.
However, the brain structure of rodents is very different from that of humans, what are the special developmental properties of the less protrusion cells in the human brain? The answer to this question is particularly important.
this is the breakthrough in this study.
in the brain structure of humans and mice (photo: MSU Human Health Atlas, Brainmaps.org) In this work, researchers used antibodies from cell surface proteins to enrich stem cells in the cerebral cortex of human embryos, combined with single-cell sequencing, brain chip culture, and real-time microscopy techniques to achieve specific types of fluorescent markers, genealogy tracing and genetic mutations in different human cortex stem cells.
they observed that a class of glial cells, endemic to primates, with outer radioactive glial cells (oRG) not only helped to produce large numbers of neurons in the gray matter of the brain, but also provided an additional source of small glial cells for white matter in the human brain.
in addition, in the late pregnancy, the protrusion precursor cells (OPC) undergo continuous symmetrical division, expanding their numbers exponentially, in preparation for the production of a large number of protrusion cells.
interesting, the new large number of OPC will also be mutually exclusive, moving in the opposite direction, to avoid local accumulation, to ensure a wide distribution of the effect.
the study authors concluded that the three properties of additional sources, continuous division and rapid diffusion significantly increased the number of protrusion cells produced, thus promoting the expansion of white matter in the cerebral cortex.
the study diagram (Picture Source: References) It is worth noting that the study authors also pointed out in the discussion section of the paper that past studies of epithelial developmental abnormal diseases such as microcephaly tend to focus on neurons, with little regard for glial cell development almost abnormalities.
," however, our study found that clinically reported disease-causing genes were not only expressed within neurons, but also had higher levels of expression in cells with fewprogenic gel precursors.
," Dr. Huang said, "this suggests that the primary role of glial cells in these genetic diseases is noteworthy."
"references " Wei Huang et al., (2020) Origins and Proliferative State of Human Oligodendrocyte Cells. Cell. DOI: