In the rodent brain, neural progenitor cells born in the ventral subventricular zone (V-SVZ) migrate to and populate the olfactory bulb with various cell types, including interneurons. The authors observed previously unknown progenitor-producing microdomains within the adult rodent V-SVZ that produced four novel subtypes of olfactory bulb interneurons and that expressed members of the NKX6.2 and ZIC family of transcription factors. This study shows an unexpected level of complexity in the postnatal V-SVZ and highlights its utility for the study of neuronal subtype specification.