Adult neural stem cells: attempting to solve the identity crisis.

A prevailing view in the literature is that the central nervous system (CNS) develops from a population of self-renewing, multipotential stem cells that persist throughout life. The in vivo identification and isolation of this rare subpopulation of cells has been the focus of much attention. This review will discuss the in vivo characterization of neural stem cells in the embryonic and adult CNS and some recent discrepancies and limitations between in vivo and in vitro assays used to identify neural stem cells. Copyright 2004 S. Karger AG, Basel.