Yves Simon, Educator
World's biggest human brain map unveiled
(Images: Allen Institute for Brain Science)
The world's biggest computerised map of the brain was released yesterday by scientists at the Allen Institute for Brain Science, in Seattle, Washington, after more than four years of cutting-edge research.
The Human Brain Atlas is an interactive research tool that will help scientists to understand how the brain works and aid new discoveries in disease and treatments.
The information used to build it comes from the analysis of two human brains, using magnetic resonance imaging (MRI) and a variation of MRI called diffusion tensor imaging.
Allan Jones, the CEO of the institute, told Wired how the brains were also chopped up into small pieces, and RNA extracted from the tissue. They used this RNA to obtain a read-out of the 25,000 genes in the human genome.
All this information was put together to create a detailed map of the brain. One thousand anatomical sites in the brain can be searched, supported by more than 100 million data points that indicate the gene expression and biochemistry of each site.
For example, a researcher could quickly create a 3D snapshot (see image below) of all the locations in the brain where Prozac's biochemical targets are expressed.
The researchers found a striking 94 per cent similarity in the biochemistry between the two brains, and discovered that at least 82 per cent of all human genes are expressed in the brain.
Allan says this isn't too surprising: When you think about the complexity of the functions of the brain, and the variety of different cell types found within the brain, it's not quite as surprising to see how much of the genome is used to serve the brain
Both brains used in the $55 million project were male, which prompted The Wall Street Journal to ask why a woman's brain had not been included. Allan told Bloomberg that eligible brain donors usually die from accidental causes or cardiac arrest, both of which disproportionately affect men. However, he says the project is currently processing a female brain, and that ultimately, the facility will run at least 10 brains through the process.
Other researchers are also attempting to map neural connections in a mouse brain, something MRI cannot do. They will turn slices of brain into digital images by an automated electron microscope. A computer will read those images, trace the outlines of nerve cells, and stack the pictures into a 3D reconstruction. Maps like these have limitless potential in drug discovery and human genetics and will no doubt be an essential step forward in the fight against disease.