MAPT and early-onset autosomal dominant Alzheimer disease: Because memory impairment is the earliest symptom of Alzheimer’s disease, we have found that loss of neurons in the CA3 area of the hippocampus due to ischemia-reperfusion episode is sufficient and contributes to memory impairment in a manner dependent on amyloid and tau protein at very early stages after brain ischemia and Alzheimer’s disease.