Luca BONFANTI - Comparative neuroplasticity - from cell markers to evolution

Despite a huge amount of new knowledge gathered in the field of brain structural plasticity, some issues remain ill-defined, creating confusion in the interpretation of results. Beside stem cell-driven neurogenesis occurring in adult neurogenic niches (adult neurogenesis), neuronal precursors in arrested maturation have also been described neurogenesis without division, based on the so-called "immature" neurons). These processes occur in different brain regions yet sharing some markers and some temporal windows. In addition, recent studies in comparative neuroplasticity introduced new elements of complexity, revealing a reduction of adult neurogenesis in the olfactory bulb and hippocampus of large-brained, gyrencephalic species if compared with small-brained rodents. Conversely, a higher occurrence of immature neurons has been found in the neocortex and amygdala of large-brained, gyrencephalic mammals. Overall, the emerging complexity is due to the incoming awareness that different plastic processes have undergone evolutionary trade-offs leading to a prevalence of some types in some species with respect to others yet coexisting at some levels.