Necessity of Hippocampal Neurogenesis for the Therapeutic Action of Antidepressants in Adult Nonhuman Primates
Tarique D. Perera, Andrew J. Dwork, Kathryn A. Keegan, Lakshmi Thirumangalakudi, Cecilia M. Lipira, Niamh Joyce, Christopher Lange, J. Dee Higley, Gorazd Rosoklija, Rene Hen, Harold A. Sackeim, Jeremy D. Coplan
The idea of neurogenesis in adult animals including humans, is a little over a decade old. Neurogenesis has been found in the hyppocampus, the neocortex, and the olfactory bulb. The focus has been on the hyppocampus and in particular the anterior dentrate gyrus and the relationship of neurogenesis to depression. Several factors are known to stimulate neurogenesis, including exercise, meditation and antidepressants. In addition, such minor changes as providing a larger and more stimulating environment can stimulate neurogenesis in rodents.
The authors have extended these studies to a major primate, the macaque, which can be induced to show symptoms of chronic depression through social isolation. The monkeys were isolated and not, given antidepressants and not, and irradiated to kill neurogenesis or not. They were tested for symptoms of depression, then terminated and their brains were examined. Their findings show that in macaques, like rodents and other mammals, antidepressants stimulate neurogenesis and this relieves depression.
Social isolation can cause depression. This can be losing a job, a loved one, being alone in a strange place, living under unhappy or unrewarding circumstances. We talk about social bonds as connection, we literally build these connections inside our brains. When these connections are broken, synapses are lost, dendrites and axons deteriorate, and even cells die. Neurogenesis in the anterior dendrate gyrus is a plastic response to this loss. Once the mechanism is revealed then ways to maximize and enhance this process can be found.
Elizabeth Gould – How Does Experience Influence the Brain?
The Royal Society for the encouragement of Arts, Manufactures and Commerce – talk – March, 2010