Scientists Create Wiring Diagram of a Mouse Brain

Posted on April 2, 2014

Connectome or wiring diagram of a mouse brain

Scientists from the Allen Institute for Brain Science have created a wiring diagram - or connectome - of a mouse brain. The scientists say they have also published the very first "comprehensive, large-scale data set on how the brain of a mammal is wired." A research paper, "A mesoscale connectome of the mouse brain," was published here in Nature. The scientists built the Allen Mouse Brain Connectivity Atlas, a genome-wide, high-resolution atlas of gene expression throughout the adult mouse brain. It has been made available at The Atlas contains more than 1.8 petabytes of data.

The scientists say the mouse brain has 75 million neurons which are arranged in a similar structure to the human brain. By comparison, the human brain has 100 billion neurons which is as many stars as there are in the Milky Way. To map the mouse brain scientists collected imaging data at resolutions smaller than a micrometer from more than 1,700 mouse brains, each of which was divided into 140 serial sections.

Ed Lein, an investigator at the Allen Institute for Brain Science, told NPR, "It's a pretty big leap. Basically, there was no information of this sort prior to this project."

David Anderson, Professor of Biology and Howard Hughes Medical Institute Investigator at the California Institute of Technology, says in a statement, "The Allen Mouse Brain Connectivity Atlas provides an initial road-map of the brain, at the level of interstate highways and the major cities that they link. Smaller road networks and their intersections with the interstates will be the next step, followed by maps of local streets in different municipalities. This information will provide a framework for what we ultimately want to understand: 'traffic patterns' of information flow in the brain during various activities such as decision-making, mapping of the physical environment, learning and remembering, and other cognitive or emotional processes."

This video shows 21 mapping experiments from the Allen Mouse Brain Connectivity Atlas. The density of axons at each voxel (dot) are displayed as overlapping circles color-coded by the area of the brain from which the axons are projecting. Take a look:

Image: Allen Institute for Brain Science