1. Neurogenesis occurs in the subventricular zone of the lateral ventricles in infants and adults. Neural stem cells and progenitor cells in the SVZ generate new neurons that migrate to other areas of the brain. 2. In infants, neuroblasts migrate from the SVZ to the olfactory bulb through the rostral migratory stream. Some cells branch off the RMS to supply the ventromedial prefrontal cortex. 3. There is evidence of declining neurogenesis with age as shown by a decrease in immature neurons in the RMS and olfactory tract between infants and adults. However, the existence of neurogenesis in the adult human brain remains an open question requiring further study.