Figure 10.

Summary and comparative aspects. A, Two main populations of non-newly generated, “immature” DCX⁺ cells are present in the cerebral cortex and capsular/pericapsular regions of the sheep brain. B, Unlike newly generated neuroblasts of the main neurogenic sites and immature neurons of the cortical layer II, which are consistently reduced with age (Fig. 5), the number of DCX⁺ cells in the sheep capsular/pericapsular regions does not vary from neonatal to adult age. Compared with results reported for laboratory rodents, our findings in sheep strongly suggests that parenchymal, non-neurogenic structural plasticity (brown areas) can be maintained/increased in large-brained, long -living mammals, thus following an opposite trend with respect to adult neurogenesis (green). C, Pallial and mixed (pallial and subpallial) origin of the DCX⁺ cells in different brain regions.