| Figure 4 |
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| A. The progression of Q through cortical neurogenesis. Q is plotted as a function of the integer cell cycle of the neurogenetic interval in the mouse. The pseudostratified ventricular epithelium (PVE) expands before Q=0.5 (corresponding to E14, as neurons of layer IV are forming) and contracts afterwards. From Takahashi et al., (1996), reproduced with permission. B. the expansion and contraction of the PVE as calculated from the progression of Q in mouse parallels the growth of the cortical plate and the formation of neocortical layers. Data from Takahashi et al. (1996); image courtesy of Richard Nowakowski. C. (below) symmetrical divisions generating mitotic cells will exponentially increase the progenitor cell population, whereas asymmetric divisions generating a mitotic and a post-mitotic daughter will keep the progenitor population at steady-state levels. |
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published 2000