in fact, dr. gieddays right now if you look at college kids there are no alarming findings their brains are turning into mush. they seem to be handling all this incoming data, and that pruning seems to be working. and that's what they could be learning. so for parents keep your eyes on their grades, and one thing we're really going to talk about, and that's tomorrow night, brian, is the sleep deprivation. because sleep absolutely has an effect on brains, and that's going to be the subject of tomorrow night's segment. >> all right. nancy snyderman, as always, thanks. and by the way, we should point out, much more on this topic on the web. dr. nancy will host a live chat tomorrow afternoon on nightly.msnbc.com. but she won't be performing any primary care. >>> up next, what does april 12th mean to you? in the history business it means a lot of things. >>> and now a word about today. this day, the 12th of april, in history. in the history business this is a big one, from small events to large. on this date