Perry Francis Bartlett, through his discovery of stem cells in the developing and adult brain of mammals and his recent successful isolation and characterisation of this stem cell, provided the first definitive evidence of the adult brain's capacity to produce new neurons, which has led to a fundamental change of view about the brain's capacity for repair and plasticity. Also, it has allowed the verification of his earlier prescient proposal that stem cells in the brain are pluripotent. Other major discoveries in developmental neurobiology include defining the regulatory actions of FGF-2, LIF and the p75NGF receptor.