This image of an Alzheimer's patient's neural network--viewed from above, with the front of the brain on the right--was created using diffusion tensor imaging, a technique that tracks water molecules moving along the length of the axons that link neuron to neuron.

Drawing on ADNI data, which helped link Alzheimer's disease to a common gene called CLU, researchers used this imaging technique in other people to discover that the brain wiring of gene carriers is impaired decades before the disease typically strikes. As the ADNI initiative grows, so will its power to uncover and attack AD at its genetic roots.