When we are fetuses, are huge number of neurons are produced. They then migrate, differentiate, and some die. Up until recently scientists thought that the neurons that we were born with were the only ones that we would ever get. However, new evidence shows that this is not the case. In fact, thousands of new cells are produced in the hippocampus daily, but they soon die. Since the hippocampus is related to learning and memory, it is safe to assume that these neurons are produced as a result of learning or memorizing something. Studies on mice show that this is the case. The mice that had learned more retained more of their neurons.
They also found that exercise had a factor in whether or not the new neurons survived. The scientists researched further and found that a mood-elevating chemical that is present during physical activity, beta-endorphin, could be the reason for this. Mice who were allowed to exercise kept more of their hippocampal neurons, but mice who had beta-endorphin inhibited and were allowed to exercise did not show an increase in the retention of their neurons. It was also found that perhaps stress had the opposite affect, and decreased the chance that the new neurons would survive.
This is very big for the science community. If we can pinpoint this mechanism it can be used to treat retrograde brain diseases such as Alzheimers and stroke. Also, it poses the question of whether or not there are other areas of the brain that can possibly regenerate themselves, or could regenerate themselves with some help. Some say that there is muscle memory, I would like to know whether or not these new neurons have anything to do with that and if the new neurons were still located in the hippocampus or in the connections between the hippocampus and the motor cortex or other areas.