Cit+ cells included both neurons and oligodendrocyte precursors. LGE-like neurons (nLGE), which expressed SP8, and only constituted 6% of the Cit+ total. As with the pTEL PAX6+ populations, this may suggest that at the earliest timepoint, D24, progenitors and the neurons that arise from them are incompletely ventralized. ERBB4− neurons (nMGE) constituted 28% of the Cit+ population, and were observed at every timepoint. These neurons could be potential striatal neurons, as many clusters lacked ZEB2 or LHX6 expression, but they may also be immature cortical interneurons yet to initiate the genetic program necessary for tangential migration. The majority of Cit+ cells were GAD1+ERBB4+SST+ cortical interneurons (nCTX), constituting 64% of all Cit+ cells. We did not observe significant PVALB RNA expression in any cluster. Lastly, oligodendrocyte precursors (oMGE) were observed at and after D100. These trends mimic in vivo patterns of cell type production.
