Discusses the aging brain and dementia, providing an overview of Alzheimer's disease. Illustrates affected areas of the brain and the abnormal cellular structures involved with AD: granulovacuolar degeneration, neurofibrillary tangles, and amyloid plaques. Discusses the stages of Alzheimer's disease and shows the physical changes in the brain cortex caused by alzheimer's. Illustrates and defines the role of neurotransmitters as messengers.