 While it has yet to have been studied in-depth in the human brain, the SVZ function in the rodent brain has been, to a certain extent, examined and defined for its abilities.With such research, it has been found that the dual-functioning astrocyte is the dominant cell in the rodent SVZ; this astrocyte acts as not only a neuronal stem cell, but also as a supporting cell that promotes neurogenesis through interaction with other cells.This function is also induced by microglia and endothelial cells that interact cooperatively with neuronal stem cells to promote neurogenesis in vitro, as well as extracellular matrix components such as tenascin-C (helps define boundaries for interaction) and Lewis X (binds growth and signaling factors to neural precursors).