Alzheimer performed an autopsy on Auguste D. and found three specific alterations in the cerebral cortex that have since proven to be characteristic of the disease. First, her brain was shrunken and atrophied. Second, the outside of the nerve cells contained deposits of a dense material that formed what we now call amyloid plaques. Third, inside the neurons was an accumulation of tangled protein fibers that we now call neurofibrillary tangles.
