Inside Alzheimer’s The PET scan (shown above, left) depicts the brain of a normal person, while the scan (above, right) shows that of a person with Alzheimer’s. Studies using PET suggest a slowing of brain activity in certain regions of the Alzheimer’s brain (Alzheimer’s Association, 2013). The neurofibrillary tangles (far right image, with tangles in pink) result from twisted protein fibers accumulating inside brain cells.

left: Jessica Wilson/Science Source; right: Thomas Deerinck, NCMIR/Science Source