The creation of new neurons, known as neurogenesis, is an important process. It is by this process that the brain forms, and most of it occurs during pre-natal development. An early theory proposed by neuroanatomists that has recently been refuted by experimental evidence is that adult neurogenesis does not occur. In adult neurogenesis, it has been observed that most of the new neurons die shortly after their formation, while only a few become integrated into the functioning structure of the brain. So what is the significance of adult neurogenesis?
While the functioning of this process is not known, it has been speculated that it is important for memory and learning processes, and is linked to stress. Stress causes a lot of people a lot of harm, and has been linked to many disorders, such as depression. Depression is a condition that is regulated by antidepressants. Know what other activity is regulated by the activity of antidepressants? You guessed it, NEUROGENESIS! A recent study showed that the brain responds to stress-relieving situations, such as those that build learning and memory, with increased neurogenesis. Stressful situations, such as those that induce physiological or psychological stress, are marked by decreased neurogenesis. A decrease in neurogenesis has been indicated to be a key factor in the progression of depression.
Of course, there are individuals out there who have reported experiments that refute the process of adult neurogenesis. One author speculates on whether or not there is true scientific evidence to back these findings, and that perhaps the new cells being formed are glial cells.
So, how can one keep the level of neurogenesis up and reduce depression? By removing oneself from physiologically and psychologically stressful situations, and getting some exercise.