FIGURE 1.

Comparison of central nervous system plasticity and adult neurogenesis in the animal world. (A) Strong reduction of brain neurogenic and reparative capacity occurs in vertebrates from non-mammals to mammals. (B) Among mammals, striking reduction is detectable in SVZ neurogenesis (a process which in laboratory rodents provides new neurons for the olfactory bulb throughout life) of large brained, long living species with reduced (humans) and absent (dolphins) olfactory brain structures. Images adapted from Sanai et al. (2011) and Parolisi et al. (2017) (reproduced with permission of Nature Publishing Group and Springer). Yellow panel: schematic representation of the reduction of SVZ neurogenesis in different animal species and at different ages (continuous red line, SGZ neurogenic niche; red dots, occurrence of scattered newly born/immature neurons).