Many different kinds of experiments support the hypothesis that memory is a brain process. I have already mentioned the sad case of people with damage to the hippocampus who are unable to form memories. When people with Alzheimer's disease lose their memories, autopsies show buildup of plaques that have destroyed neural connections. Brain scans measuring the flow of blood to regions as small as a few millimeters show what anatomical areas become active when people are presented with stimuli of different kinds similar to ones they remember. Together, such experiments provide strong evidence that when you remember something, it is because your brain has revived patterns of neural activation.