Stress can stimulate production of new adult neural stem cells. An area of the brain known as the hippocampus responds to environmental conditions, including stress such as being held in isolation, and produces new neural stem cells that are stockpiled for later use. As conditions become more favorable, such as being moved to an enriched environment with various stimuli, the neural stem cells can be used to produce new brain neurons. The new study, published in the journal Neuron, shows that adult stem cell production in the brain is responsive to experience and the environment, indicating that this may act as a form of cellular plasticity for adapting to environmental changes.

A new paper published in the journal Nature further suggests that if those stored neural adult stem cells are not used to produce new neurons, you could be more susceptible to depression. NIH researchers found that new neurons formed by adult stem cells in the brain could protect against depression and stress in a mouse model. However, mice that could not form new neurons had elevated levels of stress hormones and showed more depressive behaviors. The authors note that their results provide evidence to support a direct role for adult neuron formation in depressive illness.