Most people have heard about stem cells and their possible use with growing all kinds of new structures in the body, including growing new neurons. But what is less known is that there are really two types of stem cells. Pluripotent stem cells are what most people are familiar with. These are the types of cells that can utilized to grow into virtually any type of cell in the body. The other type of stem cells are known as multipotent cells. These are stem cells that can become only certain types of cells in a specific category, such as those that can become different types of cells in the blood, such as monocytes, lymphocytes or neutrophils. But, they cannot become anything other than a type of blood cell. One of the greatest challenges facing the field of stem cell research is in relation to the possibility of identifying and activating the correct type of multipotent stem cells for their designated use, including the correct cells that can become specific types of brain cells. Some of the things that we do know about stem cells in the brain are where they are created and replenished. One of these areas is known as the subventricular zone, just adjacent to the ventricles. Another area of stem cell production is in the olfactory bulb. As this is the area which controls the sense of smell, it is thought that more cell replenishment might be needed in this area because the cells in this area might die at a higher rate than other brain cells. This is also related to why we lose our acuity of smell as we grow older, when these cells are not replenished with the frequency and volume of our youth. Still another area of stem cell production is in the subgranular zone/dentate gyrus of the hippocampus. This area is heavily involved with memory functions and as you might suppose, requires frequent replenishment as you add more memories.
Because all of us are capable of producing our own stem cells, the ultimate possibility of being able, in the future, to use our own stem cells would virtually negate the current political and religious controversy regarding the acquisition and use of stem cells from others, if a way can be found to turn our own stem cells "on or off" as we need them.