Colored 3D diffusion imaging—using MRI technology and computer analysis—maps the brain’s white matter tracts, or fibers. The colors in this image, known as a tractogram, show the position and direction of the tracts, which connect different areas of the brain. Tractograms help neuroscientists identify white matter lesions, see the location of brain tumors in relation to the tracts, and plan neurosurgery to avoid the most critical tracts, including those that affect motor skills or senses.