Scientists have reached a major breakthrough in an ambitious global effort to map how different types of brain cells form and mature from early embryonic and fetal stages through adulthood. Experts say the findings could pave the way for new approaches to conditions such as autism and schizophrenia.
Researchers announced that they have completed the first draft of atlases for both the developing human brain and the developing mammalian brain. The work primarily examined human and mouse brain cells, with additional data from monkey brain development.
In this draft release, the research team traced how various brain cells originate, diversify and eventually mature into highly specialized types with distinct functions. They also observed how genes switch on and off at different stages of the developmental timeline.
The scientists identified key genes involved in major brain processes and uncovered similarities in brain cell development across humans and animals, along with features that are uniquely human. The studies, which also revealed previously unknown cell types, were published in Nature and affiliated journals.
This research is part of the US National Institutes of Health’s BRAIN Initiative Cell Atlas Network, an international project aimed at producing a complete atlas of the human brain.
Neuroscientist Hongkui Zeng, director of brain science at the Allen Institute in Seattle and a leader of two studies, said the brain contains thousands of cell types with remarkable diversity in their functions, collectively influencing behavior, emotions and cognition.
More than 5,000 cell types have already been identified in the mouse brain, and scientists believe the human brain contains at least as many. UCLA neuroscientist Aparna Bhaduri, another research leader, said the developing brain has long been difficult to study because of its rapid transformation, numerous cell types and limited accessibility. She noted that the new atlases now offer a far clearer picture of the components and structure of the developing brain.
The researchers said the findings have significant practical potential. By comparing human and animal brain development, scientists expect to gain deeper insights into human-specific traits, including intelligence. They added that understanding normal brain development will help identify what changes occur in diseased brains and when those changes arise, both in human tissues and in animal models.