Dr. Jeff Lichtman likes his brains sliced thin—very, very thin. Dr. Lichtman and his team of researchers at Harvard have built some unusual contraptions that carve off slivers of mouse brains as part of a quest to understand how the mind works. Their goal is to run slice after minuscule slice under a powerful electron microscope, develop detailed pictures of the brain’s complex wiring and then stitch the images back together. In short, they want to build a full map of the mind. The field, at a very nascent stage, is called connectomics, and the neuroscientists pursuing it compare their work to early efforts in genetics.