The subgranular zone (in rat brain). (A) Regions of the dentate gyrus: the hilus, subgranular zone (sgz), granule cell layer (GCL), and molecular layer (ML). Cells were stained for doublecortin (DCX), a protein expressed by neuronal precursor cells and immature neurons. (B) Closeup of subgranular zone, located between the hilus and GCL. From a paper by Charlotte A. Oomen, et al., 2009.