Figure 4.

Comparison of the length of the cell cycle (Tc) between monkey and mouse during cortical neurogenesis. Tc is compared at the beginning of the first (early), middle, and last (late) third of the total period of neurogenesis, corresponding to E40, E60, and E80 in monkeys and E11, E13, and E15 in mice. These three stages correlate respectively to the onset of neurogenesis for layer VI, the end of layer VI/onset of layer V neurogenesis, and the end of layer IV/onset of layer III neurogenesis (8, 9). (A) Tc expressed in absolute time. (B) Tc expressed as a proportion of the duration of the total neurogenetic period, which is 60 days in monkeys and 6 days in mice. Data for mice are from ref. 15.