Disguising adult neural stem cells.

A description of adult neural stem cells has remained somewhat elusive. With no unique and definitive markers to label stem cells in general, neural stem cells are difficult to identify definitively and one is forced to examine cell behavior - leading to the retrospective identification of a stem cell. The most prevalent view in the literature describes the adult forebrain neural stem cell as a relatively quiescent subependymal cell that expresses glial fibrillary acidic protein. In this review we summarize some of the recent studies that have supported or challenged this conception of the nature of the adult forebrain neural stem cell. We highlight and compare the experimental paradigms that have led to our current state of knowledge and conclude that there is no reason at present to abandon the prevailing view of adult neural stem cell identity.