FOR MANY YEARS the accepted dogma of neuroscience was that there was no neurogenesis, or birth of new neurons, in the adult brain. A corollary of this dogma was therefore that the brain did not contain stem cells. This dogma was established by the father of neuroscience, Santiago Ramon y Cajal. Today, scientists accept the presence of stem cells in the adult brain as fact. The first scientist to report adult neurogenesis was Fernando Nottebohm. Dr. Nottebohm saw new neurons in adult male canaries as they learned a new song in the spring. He was most likely not the first scientist to see adult neurogenesis, but he was the first to report it. Scientists had probably seen adult neurogenesis before, but refrained from reporting these findings—the view that there were no new neurons in the brain was accepted as fact and reporting data against this fact was a difficult action. ...