On the previous slide is a composite "mesh" map of an average healthy elderly brain. Even healthy brains lose some cells over time, but the image on the right reveals how dramatic cell loss in the brain of an Alzheimer's victim can be. The blue areas are where no excess tissue is lost relative to an average brain. Green shows areas of some neurodegeneration, and red indicates significant loss. While ADNI researchers use maps such as these to study the pattern and range of degeneration among groups of patients over time, this model could also be used to monitor the progress of the disease in a single patient.