Scott Simon talks with neurologist Richard Restak, M.D., author of the book The Secret Life of the Brain. The book accompanies a new public television series of the same name. They discuss how the brain changes after adolescence, the vividness of hallucinations in schizophrenia, and why people's names are sometimes difficult to remember. The series begins Tuesday night on PBS and runs for five weeks. Check your local listings. The companion book is published by Joseph Henry Press.