The most detailed map of the human brain in history has been published
As part of a massive project, scientists have detailed the location and inner workings of 3,300 types of brain cells. And they have only a vague idea of what most of them do. Only a fraction of these new cells were previously known to science. As part of the project, the scientists published 21 new papers in three journals, Science, Science Advances and Science Translational Medicine.
The atlas of the human brain used advanced techniques that had previously mostly been used on animals. The scientists applied transcriptomics, which involves cataloging all the RNA in individual cells (RNA is a genetic molecule that contains instructions for building proteins and performs other important functions).
The researchers also used epigenomics, which involves studying the chemical tags that sit on top of DNA and control the use of genes. The individual studies included in BICCN included data from hundreds of thousands to millions of brain cells .
By combining these methods, researchers have created single-cell-scale maps of the developing and adult human brain, as well as the brains of primates such as monkeys (Callithrix) and macaques (Macaca). In some studies, scientists have also examined the brains of chimpanzees (Pan troglodytes) and gorillas (Gorilla).
This allowed for a direct comparison between the brains of humans and non-human primates and showed that many cell types found in our brains are also found in chimpanzees and gorillas, The New York Times reported. But while we have the same cell types, the gene activity of these cells in humans and apes is markedly different, and that changes how these cells work together.
"It's actually the connections - the way these cells talk to each other - that differentiate us from chimpanzees," Trygve Bakken, a neuroscientist at the Allen Institute who worked on the primate research, told the Times.
"This is not just an atlas," Ed Lane, a neurobiologist at the Allen Institute for Brain Research and lead author of five papers, told MIT Technology Review. "The project opens up a whole new field. You can now look into the brains of species at extremely high cellular resolution. This has not normally been possible in the past."
The research was conducted as part of a National Institutes of Health project known as Brain Research through Advancing Innovative Neurotechnologies or BICCN. It was launched in 2017; the goal is to catalog cells found in the brains of mice, humans, and monkeys.