Interneuron migration genes DCX, CXCR4, CXCR7, and ERBB4 were expressed at moderate or high levels in postmitotic cells, with CXCR4 and CXCR7 also expressed in Cit− cells (Figure 2B)(Anton et al., 2004; Friocourt et al., 2007; Vogt et al., 2014; Wang et al., 2011). SST was expressed in both Cit-negative and -positive populations at D54 and 100. DCX expression is highest in immature neurons and downregulated in the most mature and functional cells during development (Brown et al., 2003; Couillard-Despres et al., 2005). SST expression in Cit− cells represents a small number of SST neurons that downregulates DCX and Citrine, as 3.3 ± 1% and 9.6 ± 2.9% of SST-expressing cells were Cit− at D54 and D100, respectively (Figure S3). SST subtype markers, NPY and CALB2 were expressed in Cit+ cells at D54 and D100, but CCK, RELN and NOS1 expression were low. AMPA receptors (GRIA2, GRIA4) were expressed in Cit+ cells at D54 and D100 (Akgul and McBain, 2016). There was low or no expression of PVALB, VIP or HTR3A, indicating that these interneuron subtypes were not produced. Raw
