台大心理系

A fascinating feature of the nervous system is that it provides plasticity of brain structure and function that allows animals to adapt to changes in their environment. Ongoing neurogenesis in the postnatal brain may be one of the mechanisms by which animals respond to change in their world. Adult neurogenesis in the central nervous system of higher vertebrates occurs from songbirds, rodents, nonhuman primates to humans. Postnatal neural stem cells are present in the mammalian subventricular zone (SVZ) adjacent to the lateral ventricle and in the subgranular zone (SGZ) of hippocampal dentate gyrus (DG). Neural stem cells in the SVZ generate transit-amplifying cells and then neuroblasts, which migrate tangentially along the rostral migratory stream (RMS) to the olfactoey bulb (OB) and differentiate into interneurons, whereas neuroblasts generated in the SGZ migrate radially into the nearby dentate gyrus and differentiate into granule cells. Accumulating evidence indicates that adult-generated OB and DG neurons are functionally incorporated into existing neural circuits and play important roles in innate behaviors. Here, I am going to show that pheromones from familiar and unfamiliar males exert different effects on neurogenesis in the adult female OB, which may provide a mechanism for the Bruce effect. In addition, I will present that maternal immune activation (MIA) during pregnancy, a risk factor for schizophrenia, leads to defective adult neurogenesis in the SVZ–OB pathway, and the impairment of adult neurogenesis may cause deficits in olfactory functions. Finally, I will discuss that Rab18, a Ras-like small GTPase, modulates adult neurogenesis and maternal behaviors. Taken together, intrinsic and extrinsic factors regulate adult neurogenesis, which is required for physiological and pathological functions in the mammalian brain.