The anatomy of the neurogenic subventricular zone in the adult rodent and human brain. (A) Sagittal view of a rodent brain showing the sites of neurogenesis in the subventricular zone/olfactory bulb (SVZ/OB) system. (B) Schematic drawing of the composition and cytoarchitecture of the adult rodent SVZ. (C) Coronal view of the adult human brain showing the basal ganglia and lateral ventricles. (D) Schematic drawing depicting the cellular composition and cytoarchitecture of the adult human SVZ, consisting of four layers: Layer I – ependymal cell layer (green), Layer II – hypocellular gap, Layer III – astrocytic ribbon, containing astrocytes and migrating neuroblasts, Layer IV – transitional zone, containing oligodendrocytes and separating the SVZ from the striatum rich in neurons. RMS: rostral migratory stream; DG: dentate gyrus; LV: lateral ventricle.