FIGURE 2.

Temporal patterning in neurogenesis. (A) Generating distinct neurons at different stages could be either achieved by a common multipotent progenitor that undergoes a cascade (left) or by a pool of progenitors that differ both in potency and in the time to commit to neurogenesis (right). (B) Mammalian temporal patterning and neurons generated in each temporal window. Upper panel: Birth date of cortical projection neurons (Caviness, 1982) and V1 spinal interneuron (Stam et al., 2012) with temporal transcription factor expression in neural progenitors at each temporal window (Sagner et al., 2021); lower panel: Birth date of retinal cells and corresponding temporal transcription factors in retinal progenitors [RGC: retinal ganglion cell; HC: horizontal cell; AC: amacrine cell; Rod: rod cell (photoreceptor); BC: bipolar cell; MC: Müller cell] (Elliott et al., 2008; Mattar et al., 2015; Javed et al., 2020). (C) Different regions in the fly nervous system undergo different cascades of temporal factors to generate different types of neurons.