Neural stem cells in the adult ventricular-subventricular zone (V-SVZ) continuously generate new neurons throughout life. These new neurons tangentially migrate through the pathway called the rostral migratory stream (RMS) towards the olfactory bulbs. They form elongated cell aggregates surrounded by astrocytic tunnels and maintain their immature, migratory phenotype until they reach the core of the olfactory bulbs. In the olfactory bulbs, the new neurons leave the RMS for one of the two layers, granule cell layer and glomerular layer, where they are differentiated into interneurons. Although recent studies suggest that sensory input affects several steps in neurogenesis, the mechanisms regulating the migration and maturation of neurons in the adult olfactory bulbs are not fully understood. My laboratory is studying neurogenesis in the V-SVZ in the physiological and pathological conditions using mice, zebrafish and common marmosets. Using in vitro and in vivo imaging techniques in combination with various genetic approaches, we have studied the morphology and movement of new neurons migrating towards and within the olfactory bulbs. I will present our recent progress towards understanding the molecular and cellular mechanisms regulating olfactory bulb neurogenesis. Our data indicate that the migration and maturation of new neurons depend on their interaction with other cell types including glial cells. We will also compare the mechanisms for neuronal migration in the injured brain with those in the normal condition.