These are all the connections in a bit of mouse brain the size of a grain of sand

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Previous wiring diagrams, as the images are known, have mapped “connectomes” for the fruit fly and human brains. One reason MICrONS has been so well received is that the data set has the potential to improve scientist’s understanding of the brain and possibly help them treat brain disorders.

Venkatesh Murthy, a professor of molecular and cellular biology at Harvard University who studies neural activity in mice but was not involved in the study, says the project gives him and other scientists “a bird’s-eye view” into how single neurons interact, offering an exquisitely high-resolution “freeze frame” image that they can zoom into.

R. Clay Reid, a senior investigator at the Allen Institute and another lead scientist for the MICrONS project, says that before the program’s research was complete, he would’ve thought this level of reconstruction was impossible.

Reid says that with machine learning, the process of turning two-dimensional wiring diagrams of the brain into three-dimensional models has gotten exponentially better. “It’s a funny combination of a very old field and a new approach to it,” he says.

Reid compared the new images to the first maps of the human genome, in that they provide foundational knowledge for others to use. He envisions them helping others to see structures and relationships inside the brain that were previously invisible.

“I consider this, in many ways, the beginning,” says Reid. “These data and these AI-powered reconstructions can be used by anyone with an internet connection and a computer, to ask an extraordinary range of questions about the brain.”