Nobel-prize-winning Colombian novelist Gabriel Garcia Marquez once wrote of a mythical town in the middle of the jungle whose residents suffer from a mysterious affliction that erases their memories. Today, in a region of Colombia called Antioquia, reality appears to be imitating fiction -- in a way that may answer questions for all of us.An extended family in Colombia with a genetic mutation causing Alzheimer’s may help scientists prevent the disease someday. Lesley Stahl reports on the groundbreaking study, featuring University of California, Santa Barbara's Dr. Ken Kosik.