From Kurzweil:
UC Berkeley researchers have uncovered exactly how acute stress — short-lived, not chronic — primes the brain for improved performance. In studies on rats, Daniela Kaufer, associate professor of integrative biology at the University of California, Berkeley and post-doctoral fellow Elizabeth Kirby they found that significant but brief stressful events caused stem cells in rat brains to proliferate into new nerve cells that, when mature two weeks later, improved the rats’ mental performance. “I think intermittent stressful events are probably what keeps the brain more alert, and you perform better when you are alert,” said Kaufer. Kaufer is especially interested in how both acute and chronic stress affect memory, and since the brain’s hippocampus is critical to memory, she and her colleagues focused on the effects of stress on neural stem cells in the hippocampus of the adult rat brain. Neural stem cells are a sort of generic or progenitor brain cell that, depending on chemical triggers, can mature into neurons, astrocytes or other cells in the brain.
…What exactly is “good” stress?
Kaufer noted that exposure to acute, intense stress can sometimes be harmful, leading, for example, to post-traumatic stress disorder. Further research could help to identify the factors that determine whether a response to stress is good or bad. “I think the ultimate message is an optimistic one,” she concluded. “Stress can be something that makes you better, but it is a question of how much, how long and how you interpret or perceive it.”
More here.