Neurogenesis and the olfactory bulb

Professor Pierre Lledo explains that the olfactory bulb is a primary site of neurogenesis - one of the few areas in the brain where new neurons are generated throughout life.

The olfactory bulb is able to incorporate newborn neurons throughout life. This continuous production of newborn neurons was really a surprise when it came. It was really a very recent discovery which was probably less than 15 years ago. In fact we are discovering that the brain can produce newborn neurons that are completely immature - they don't know where they have to go, they are just arriving. Then there is a very unique way to select them. Basically, most of them are dying when they arrive in the olfactory bulb after a few weeks. In two weeks, for instance, we lose 50% of them that just arrived. But in fact, there is a selection, for those that are located in the right place when these circuits will be activated by some specific odorants, then these newborn ones will be instructed to survive, and they will never die. Therefore, this is a way to build circuits and to keep information right there in the olfactory bulb, by having these newcomers throughout life.