In the SVZ, the neuregulin receptor, ErbB4, is primarily expressed by immature neuroblasts but is also detected in a subset of astrocytes, ependymal cells, and Dlx2+ precursors. Of the neuregulin ligands, both neuregulin-1 and -2 are expressed by immature neuroblasts. ErbB4 activation is thought to be required for neuregulin-1 and -2-mediated regulation of cell proliferation and neuroblast migration in the SVZ (Ghashghaei et al., 2006). ErbB4 regulates neuroblast migration and organization in the RMS (Anton et al., 2004). In the DG, ErbB4 regulates formation of radial glial cells (Zheng and Feng, 2006). All of the above mentioned critical players in the neurogenic niche interact with known mediators of AD pathology, as described in detail in the following paragraphs, providing an intriguing mechanistic link between AD and neurogenesis (Fig. 1).
