It is well-known that chronic stress increases our risk for obesity and heart disease, and research has also shown that it impairs memory.
However, scientists have been unclear how short bursts of stress—like writing a final exam or competing in a tournament—affect the brain. Now, a new study led by Senior Fellow Daniela Kaufer (UC Berkeley) shows that short-lived stress, also called acute stress, improves cognition.
Brain cells called astrocytes (pink) appear to be key players in the response to acute stress. CREDIT: Daniela Kaufer & Liz Kirby.
Using rats as their experimental model, the research team looked specifically at the hippocampus, an area of the brain responsible for memory, and found that short moderate stress produced new neurons. And two weeks later, once the new brain cells matured, the rats had better memory. The findings are published in the journal eLife.
“We are so used to thinking about the harmful effects of stress that we were surprised to see it can have a positive effect on the brain, including performance,” says Kaufer. “It will be interesting to look deeper into the role of the new born cells in memory function and ask how it relates to mental health, particularly in instances of post-traumatic stress disorder, depression and anxiety.” Once Kaufer and her team noticed the positive effect of stress on the brain, they began to ask how it was actually happening. They suspected that an array of proteins called growth factors that are known to regulate the growth and proliferation of new brain cells could be implicated.
Sure enough, the team found that the levels of one protein in particular, called fibroblast growth factor 2, were elevated in response to the stress and that the protein was triggering the stem cells in the hippocampus to develop into neurons.
“My interactions in CIFAR’s Child & Brain Development program were critical in shaping my research questions in this study,” says Kaufer. “During the preliminary stages of my work, I received feedback from Tom Boyce and Marla Sokolowski, co-directors of the program, as well as other members of the group when I presented my findings at meetings.”
Although Kaufer and her team have identified a mechanism by which moderate acute stress can have beneficial effects on cognition, experts also know that acute stress can be harmful, like when painful experiences lead to post-traumatic stress disorder. More research is now needed to better understand how and why our responses to stress can differ so greatly.
This research was funded by the National Institute of Mental Health of the National Institutes of Health, the National Alliance for Research on Schizophrenia and Depression, the California Institute for Regenerative Medicine, and the U.S. Department of Defense.