AD causes profound degeneration cerebral cortex and loss of neurons in neocortex and hippocampus (119-121). AD is the most common type of dementia occurring in middle and late life, affecting 7-10% of individuals >65 years of age and possibly 40% of people >80 years of age (122). The prevalence of AD is increasing proportionally to increased life expectancy (estimates predict that 25% of the population will be >65 years of age in the year 2050). In the United States, AD now affects >4 million people (123).