The majority of iN cells described in this report are excitatory and express markers of cortical identity. One of the next important steps will be to generate iN cells of other specific neuronal subtypes and from human cells. A low proportion of iN cells expressed markers of GABAergic neurons, but no other neurotransmitter phenotypes were detected. Our data suggest the intriguing possibility that additional combinations of neural transcription factors might also be able to generate functional neurons whose phenotypes remain to be explored.
