PET Scans of Healthy and Alzheimer’s Brains PET scans are one of a variety of brain imaging technologies that psychologists use to observe the living brain. The four brain images on the top each come from a person suffering from Alzheimer’s disease; the four on the bottom each come from a healthy person of similar age. The red and green areas reflect higher levels of brain activity compared to the blue areas, which reflect lower levels of activity. In each image, the front of the brain is on the top and the back of the brain is on the bottom. You can see that the person with Alzheimer’s disease, compared with the healthy person, shows more extensive areas of lowered activity toward the front of the brain.
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