Cell type specification within the embryonic basal ganglia is regulated at multiple levels. Distinct subdivisions within this region generate distinct neurons. For instance, the lateral ganglionic eminence (LGE) generates striatal projection neurons whereas the medial ganglionic eminence (MGE) generates pallidal projection neurons. Domains within the MGE are biased towards generating different cell types; whereas the rostrodorsal MGE largely produces cortical and striatal interneurons, the caudoventral MGE largely produces pallidal projection neurons (Flandin et al., 2010; Nobrega-Pereira et al., 2010). Distinct MGE-derived cortical interneuron subtypes appear to be generated from the same progenitors, perhaps in a temporal sequence (Brown et al., 2011).
