clusters displayed weak enrichment for NPC character, but lacked mature neuronal identity (Figure S4B), and thus, were classified as intermediate progenitors. Three of the six intermediate clusters highly expressed ATP and oxidoreduction metabolic genes, and were marked as high-metabolic intermediates (HMI1-3). Because the metabolic process is known to switch from aerobic glycolysis to oxidative phosphorylation throughout neuronal development (Zheng et al., 2016), HMIs are perhaps progenitor cells undergoing the adaptation of the energy metabolism.