Final answer:
In old age, neurogenesis occurs in the hippocampus and olfactory bulb.
Step-by-step explanation:
In old age, neurogenesis occurs in two parts of the brain: the hippocampus and the olfactory bulb.
The hippocampus is a brain structure involved in learning and memory. Approximately 1000 new neurons develop in the hippocampus each day, although most of them will die. Researchers have found that an increase in the number of surviving new neurons in the hippocampus is correlated with how well rats learn a new task.
The olfactory bulb is responsible for processing odors. Neurogenesis in the olfactory bulb allows for the integration of new olfactory sensory neurons that detect and process smells.