Researchers at the University of California, Berkeley, have started an ambitious project to build a brain atlas. According to neuroscientist John Ngai, the goal is to create a catalogue of different brain cells. "The human brain contains about 80 billion neurons, nerve cells. And of the neurons we suspect there could be hundreds, if not thousands of types of distinct types of those cells, but until recently we really haven’t had a way of categorizing or classifying those cells in a quantitative or rational way." But why do researchers need this mapping tool? "In order to understand how the brain processes information and gives raise to things like cognition, emotion, we really need to know what different parts are." Ngai also hopes this atlas will help scientists understand brain cells’ connections well enough to launch new therapies for treating cognitive and neurological diseases.