The<unk>  is a known site of neurogenesis and self-renewing neurons in the adult brain, serving as such due to the interacting cell types, extracellular molecules, and localized epigenetic regulation promoting such cellular proliferation. Along with the subgranular<unk>  of the dentate gyrus, the<unk>  serves as a source of neural stem cells (NSCs) in the process of adult neurogenesis. It harbors the largest population of proliferating cells in the adult brain of rodents, monkeys and humans. In 2010, it was shown that the balance between neural stem cells and neural progenitor cells (NPCs) is maintained by an interaction between the epidermal growth factor receptor signaling pathway and the Notch signaling pathway. While it has yet to have been studied in-depth in the human brain, the<unk>  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<unk> ; 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). The human<unk>  is different, however, from the rodent<unk>  in two distinct ways; the first is that the astrocytes of humans are not in close juxtaposition to the ependymal layer, rather separated by a layer lacking cell bodies; the second is that the human<unk>  lacks chains of migrating neuroblasts seen in rodent<unk> , in turn providing for a lesser number of neuronal cells in the human than the rodent. For this reason, while rodent<unk>  proves as a valuable source of information regarding the<unk>  and its structure-to-function relationship, the human model will prove significantly different. Epigenetic DNA modifications have a central role in regulating gene expression during differentiation of neural stem cells. The conversion of cytosine to 5-methylcytosine (5mC) in DNA by DNA methyltransferase DNMT3A appears to be an important type of epigenetic modification occurring in the<unk> . In addition, some current theories propose that the<unk>  may also serve as a site of proliferation for brain tumor stem cells (BTSCs), which are similar to neural stem cells in their structure and ability to differentiate into neurons, astrocytes, and oligodendrocytes. Studies have confirmed that a small population of BTSCs can not only produce tumors, but they can also maintain it through innate self-renewal and multipotent abilities. While this does not allow for inference that BTSCs arise from neural stem cells, it does raise an interesting question as to the relationship that exists from our own cells to those that can cause so much damage.
Subventricular zone
Proisocortex
Watershed area 
Periventricular nucleus
Fusiform body area
Postcentral sulcus
Periaqueductal gray
Cortical minicolumn