While it’s well-established that chronic stress has all sorts of harmful effects, including on memory and cognition, the judgment on brief bouts of acute stress has been more equivocal. There is a certain amount of evidence that brief amounts of stress can be stimulating rather than harmful, and perhaps even necessary if we are to reach our full potential.
A recent rat study has found that brief stressful events caused stem cells in the hippocampus to proliferate into new neurons that, when mature two weeks later, improved the rats’ mental performance. But note that their performance took time to improve — there was no benefit only two days after.
Chronic stress also impacts the creation of new neurons, but in the opposite direction — it suppresses neurogenesis. The difference probably lies in how long the stress hormones remain elevated. Previous research modeling PTSD in rodents has found that severity and length are crucial variables.
This new study shows that higher levels of stress hormone initially increase the production of new neurons in response to the release of a protein, fibroblast growth factor 2 (FGF2), but these need time to develop. Interestingly, FGF2 deficiency has been linked to depression, and depression is also known to be associated with a reduction in neurogenesis.
(2013). Acute stress enhances adult rat hippocampal neurogenesis and activation of newborn neurons via secreted astrocytic FGF2.
eLife. 2, e00362 - e00362.
Full text available at http://elife.elifesciences.org/content/2/e00362