Analysis of microarray data to identify DEGs between BPD and control samples failed to detect significant changes at NP or E stage neurons. It should be noted that we applied criteria that we believed would minimize false positives in our identification of DEGs (see Materials and Methods). The ability to identify DEGs only in the L neuronal population indicates that the maturity level of neurons may be an important factor to consider for transcriptomic studies of iPSC-derived neurons. This contention is supported by our observations (Fig 3 and S5 Table) that expression of key synaptic markers and proteins involved in the regulation of neuronal function progressively increase in expression from E to L neurons. The timing of neuronal differentiation from iPSCs has been intensively debated in the field with a longer differentiation duration reported to have clearer impact on neuronal function [48].
