The BRAIN Initiative, the 9-year-old, multibillion-dollar U.S. neuroscience effort, today announced its most ambitious challenge yet: compiling the world’s most comprehensive map of cells in the human brain. Scientists say the BRAIN Initiative Cell Atlas Network (BICAN), funded with $500 million over 5 years, will help them understand how the human brain works and how diseases affect it. BICAN “will transform the way we do neuroscience research for generations to come,” says BRAIN Initiative Director John Ngai of the National Institutes of Health (NIH).
BRAIN, or Brain Research Through Advancing Innovative Neurotechnologies, was launched by then-President Barack Obama in 2013. It began with a focus on tools, then developed a program called the BRAIN Initiative Cell Census Network, resulting in a raft of papers in 2021. The studies combined data on the genetic features, shapes, locations, and electrical activity of millions of cells to identify more than 100 cell types across the primary motor cortex—which coordinates movement—in mice, marmosets, and humans. Hundreds of researchers involved in the network are now completing a cell census for the rest of the mouse brain. It is expected to become a widely used, free resource for the neuroscience community.
Now, BICAN will characterize and map neural and nonneuronal cells across the entire human brain, which has 200 billion cells and is 1000 times larger than a mouse brain. “It’s using similar approaches but scaling up,” says Hongkui Zeng, director of the Allen Institute for Brain Science, which won one-third of the BICAN funding. Zeng says the results of the effort will serve as a reference—a kind of Human Genome Project for neuroscience.
Other groups will add data from human brains across a range of ancestries and ages, including fetal development. “We will try to cover the breadth of human development and aging,” says Joseph Ecker of the Salk Institute for Biological Studies, which leads BICAN studies of epigenetics, the study of heritable changes that are passed on without changes to the DNA. Ngai expects BICAN to study several hundred human brains overall, although investigators are just starting to work out details. “The sampling and coverage is going to be a big, big topic of discussion,” Ngai says.
Another $36 million over 3 years announced today will fund the BRAIN Armamentarium, which will develop viral vectors and lipid nanoparticles that home in on and genetically tweak specific types of brain cells. These tools will help scientists study cell function and develop disease treatments.
A third project called BRAIN CONNECTS focuses on tracing wiring diagrams in mammalian brains; early next year it will make $30 million in grants running up to 5 years. Altogether, NIH has spent $2.5 billion so far on BRAIN, a figure it expects to reach $5.2 billion by the end of 2026.