The biological restoration of central nervous system architecture and function: Part 2 - Emergence of the realization of adult neurogenesis

BEFORE THE 1960s, adult mammalian neurogenesis was conceptually unimaginable. Despite 45 years of observations supporting this revolutionary phenomenon, many scientists rejected this notion until irrefutable evidence provided at the end of the 20th century established that lifelong neuronal generation occurs in the adult mammalian brain. Today, in place of being viewed as a nonregenerative dormant organ, a defining characteristic of the brain is its plasticity, or capacity to undergo environment- and activity-related cytophysiological remodeling. In this second article in a 5-part series on stem cells, we trace the milestones that gave birth to a new era in neuroscience: the realization of adult mammalian neurogenesis.