Most adults fear the onset of dementia in general, and Alzheimer's disease in particular, more than physical disability. Many ask: What is Alzheimer's disease? Could I have it? Clear answers about Alzheimer's dementia and what is required to live a long, mentally healthy life requires first an understanding of how the brain's many types of cells connect, share and disengage. Recent studies show unequivocally that the non-neuron cells of the brain, the glia and microglia, actively participate in maintaining its well-being. Yet, glia and microglia are also significant participants in the demise...