 The human SVZ is different, however, from the rodent SVZ 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 SVZ lacks chains of migrating neuroblasts seen in rodent SVZ, in turn providing for a lesser number of neuronal cells in the human than the rodent.For this reason, while rodent SVZ proves as a valuable source of information regarding the SVZ 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.