Strategies for direct reprogramming of iNPCs from somatic cells. iNPCs generated from different strategies. (A) Direct reprogramming of iNPCs by ectopic expression of defined transcription factors. (B) Direct reprogramming of region-specific iNPCs by expression of lineage-specific transcription factors. (C) Direct reprogramming of neuronal subtypes-specific iNPCs by using sets of defined transcription factors. (D) Generation of neuronal subtypes through direct reprogramming in vitro and in vivo.