By any standard, Derek Paravacini is an exceptional pianist. Stephen Wiltshire can draw whole cityscapes from memory with uncanny accuracy. Both are savants with severe learning disabilities due to autism. Focusing on these two case studies, this program looks at how a disability sometimes unlocks extraordinary abilities, as well as how research on savants has led to a better understanding of brain function. Allan Snyder, professor of science and the mind at the University of Sydney, discusses several theories of savant skills, while Dr. Bruce Miller shares his work on dementia which led him to identify a region of the brain that when damaged produces savant behavior. Original BBCW broadcast title: Fragments of Genius. (50 minutes)