FIG. 1.

Anatomical location and cell composition of the SVZ. (A) Schematic showing location of SVZ (red) in the sagittal plane. Neural stem cells and transit amplifying progenitors give rise to neuroblasts which migrate long distance in the rostral migratory stream (RMS) to the olfactory bulb. The RMS route is shown with a thick black line and the normal direction with a thick arrow. Neuroblasts migrate out of the RMS into the olfactory bulb (OB) in random fashion (thin arrows). (B) Whole-mount immunohistochemistry showing SVZ astrocytes (glial fibrillary acidic protein, GFAP - white), neuroblasts (Gad (65)-GFP, green) and blood vessels (platelet endothelial cell adhesion molecule PECAM, red). Note that neuroblasts are frequently associated with astrocytes and blood vessels. (C) Coronal cross section showing location of SVZ (red). (D) Cell composition of SVZ with cells color coded. Note that SVZ astrocytic stem cells have a basal process protruding amongst the ependymal cells and make ventricular contact. Niche astrocytes are generally located on the striatal (STR) side of the SVZ. Small microglial cells have processes that interdigitate other cells. Mercier has described a complex network (fractones) of specialized extracellular matrix around SVZ cells emanating from blood vessels. LV lateral ventricle. (To see this illustration in color the reader is referred to the web version of this article at www.liebertonline.com/ars).