More Brain Points

Neurogenesis, or the generation of new neurons, was once thought to only occur during embryonic development. It is now known that neurogenesis continues well beyond embryonic and juvenile development in three areas of the nervous system. Those three areas are the hippocampus, the olfactory bulb, and the olfactory neuroepithelia. Jessica H. Brann and Stuart J. Firestein of Loyola University Chicago are interested in neurogenesis beyond embryonic and early postnatal development in the olfactory bulb and and olfactory neuroepithelia. Their main focus is how neurogenesis declines with age. There are less stem cells present for neurogenesis as an individual ages because more mutations occur making them unfit for neurogenesis. It was always known that the environment affects stem cells and their ability to create new neurons. Brann and Firestein came to the conclusion that the environment affects stem cells more than previously thought. They found that stem cells in the olfactory epithelium are more active than the stem cells in the remainder of the nervous system. This means that these cells are under some sort of constant stress that requires higher rates of neurogenesis. From these findings, they concluded that neurogenesis plays an important role in combatting environmental damage in the olfactory system.
Kevin G. Bath and Colleagues of Cornell University are also interested in lifelong neurogenesis in the olfactory system. They identified a signaling molecule that regulates neurogenesis. This molecule is known as Brain Derived Neurotrophic Factor (BDNF). Lack of, or a mutation to the molecule in rats showed poor survival rates of newborn neurons. This is indicative for the Loyola team because it may give some insight as to how age affects BDNF which would in turn affect neurogenesis as individuals aged.
There is still much to be to explored in the field of lifelong neurogenesis; but with each new discovery, we are one step closer to understand the process and its necessity.

Variant Brain Derived Neurotrophic Factor (Val66Met) Alters Adult Olfactory Bulb Neurogenesis and Spontaneous Olfactory Discrimination
http://www.jneurosci.org/content/28/10/2383.full

A Lifetime of Neurogenesis in the Olfactory System
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4071289/