imroos miller is professor of neurology and psychiatry at the university of psychiatry san francisco and once again my cohost is dr. eric kandel. he is as you know a nobel lawyer yet at the university and a howard hughes medical investigators. he gets our program off this evening telling us what it is we're about to see and talk about. we're full of stories of alzheimer's. people have been touched by it, their parents, somebody, their grandparents. we know there's something called age-related memory loss. how can we understand what we want to discover in this conversation? >> as you pointed out, it's very helpful to divide memory loss with age into two categories. what's called age-related memory loss, normal energy or benign senescent forgetfulness and the dementias. benign senescence forgetfulness like your muscles get weaker and stiffer so there's a weakening with age. this is in contrs to dementia which is a progressive much more serious disease. and it's impacts other aspects of memory storage. with normal aging, there's good news. as you're going to hear from david holtsman. >>