Scientists have reached a major milestone in an ambitious initiative to chart how different types of brain cells arise and mature from the earliest embryonic and fetal stages to adulthood, knowledge that could point to new ways to fight certain brain-related diseases such as autism and schizophrenia.
The researchers said they have completed the first draft of the atlases of human and mammalian brain development.
The research focused on human and mouse brain cells, as well as monkey brain cells. In their initial project, the scientists mapped the development of different types of brain cells – tracking how they are born, differentiate and mature into different types with unique functions. They also tracked how genes were turned on or off in these cells over time.
Scientists have identified key genes that control brain processes and discovered some common features of brain cell development between human and animal brains, as well as some unique aspects of the human brain, including the identification of previously unknown cell types.
The results are detailed in a collection of studies published in Nature and related journals.
The study is part of the BRAIN Initiative Cell Atlas Network, or BICAN, an international scientific collaboration to create a comprehensive atlas of the human brain.
“Our brain has thousands of cell types with an extraordinary variety of cell properties and functions, and these diverse cell types work together to produce diverse behaviors, emotions, and cognition,” said neuroscientist Hongkui Zeng, director of brain science at the Allen Institute in Seattle and lead author of the two studies.
Researchers have found more than 5,000 types of cells in the mouse brain. It is believed that there are at least that many in the human brain.
“The developing brain is an incredibly enigmatic structure because it is difficult to access, made up of many different cell types, and changes rapidly. “While we knew the large-scale shifts that occur during brain development, we now have a much more detailed understanding of what the parts of the developing brain are, thanks to this set of atlases,” said UCLA neuroscientist Aparna Bhaduri, another of the study’s leaders.
The research promises important practical applications. “First, by studying and comparing brain development in humans and animals, we will better understand human specialization and where our unique intelligence comes from. Second, by understanding normal brain development in humans and animals, we will be able to better study what changes occur in the diseased brain—when and where—both in diseased human tissue and in animal disease models,” Zeng said.
By gaining this knowledge, scientists hope to achieve more precise gene and cell therapy for a range of human diseases, Zeng said. It is hoped that the results will lead to a deeper understanding of autism, attention deficit hyperactivity disorder, schizophrenia and other diseases known to occur during brain development.
Areas of the brain for which the researchers created atlases for cell type development included the neocortex, which is part of the outer layer of the brain where higher cognitive functions originate, and the hypothalamus, a small structure deep in the brain that helps regulate body temperature, blood pressure, mood, sleep, sex drive, hunger and thirst.
One study found that a subset of cells in human brain tumors resemble embryonic progenitor cells — a kind of cell in an embryo that can change into specific types in a specific brain region — raising the possibility that such tumors can hijack developmental processes to cause malignancy.
Researchers have discovered some unique aspects of the human brain. One example is the long process of differentiation of cortical cell types due to the long period of development of the human brain from the fetus to adolescence compared to the more rapid development time in animals.
Among the newly identified types of brain cells were some in the cerebral cortex and the striatum, an area that controls movement and some other functions.
There is still work ahead. “The goal is to eventually understand not only what parts of the developing brain are, but also to describe what happens in neuropsychological and neuropsychiatric disorders that cause vulnerability during development,” Bhaduri said.
“This is also relevant to brain cancer, which my lab is also studying, because in brain cancer these parts of development reoccur. So this is a really big goal and it will take time to fully understand and treat all of these disorders. But this set of documents is good progress,” Bhaduri said.
Published – 07 Nov 2025 16:15 IST
