Researchers at Massachusetts General Hospital in Boston are using an MRI technique called diffusion spectrum imaging to create 3D brain models. The method uses magnetic resonance signals to track the movement of water molecules in the brain.

Water diffuses along axons – neural wires. These diffusion measurements map the wires, creating a detailed blueprint of the brain's connectivity. On the medical side, radiologists are beginning to use the method to map the brain prior to surgery, for example, to avoid important fiber tracts when removing a brain tumor. Diffusion imaging is helping better understand the structures that underlie the ability to see, speak, and remember.

A typical brain scan shows a muted gray rendering of the brain, easily distinguished by a series of convoluted folds. But according to Van Wedeen, a neuroscientist at Boston’s Massachusetts General Hospital, that image is just a shadow of the real brain. The actual structure--a precisely organized tangle of nerve cells and the long projections that connect them--has remained hidden until relatively recently. The accompanying photo is an image of a brain was composed by diffusion spectrum imaging.