Acute stress enhances memory: Study

A new study investigating the manifestations of acute stress on performance reveals that short-term or acute physical stress may enhance learning and memory.

Researchers at the University at Buffalo (UB), using rodents as an animal model, discovered acute stress could have a positive impact on memory and learning via the effect of the stress hormone corticosterone (cortisol in humans) on the brain’s prefrontal cortex, which is a vital region controlling learning and emotions.

Specifically, it was observed that a short stressful incident increases transmission of the neurotransmitter glutamate thereby boosting the working memory.

A senior author of the study, Zhen Yan, professor of physiology and biophysics at UB stated, “Stress hormones have both protective and damaging effects on the body. This paper and others we have in the pipeline explain why we need stress to perform better, but don’t want to be stressed out.”

The study on rodents
To analyze the effect of acute stress on working memory, the researchers trained rats in a maze until they could accomplish it accurately 60-70 percent of the time.

After the animals acquired perfection for two consecutive days, half of them were put through a 20-minute forced swim, which served as a stressful incident. They were then were put through the maze again.

Observations by the researchers
The researchers observed that the strained rats were prone to making less mistakes when put through the maze both four hours after the tense experience and one day post-stress, as opposed to the relaxed rats.

In order to verify if the corticosterone neuropathway attributed to the enhanced memory, researchers injected one group of rats before the stressful forced-swim with a medicinal compound that blocks the pathway, and injected another group with saline.

The research established that the group administered saline which did not disrupt the corticosterone neuropathway performed better in the maze than the other group.

In addition the investigators also noted that the stressful experience did not increase depression or anxiety in the animals.

Study identifies a novel mechanism
Yan stated, “Several key brain regions involved in cognition and emotions, including the prefrontal cortex, have been identified as the primary target of corticosteroid, the major stress hormone.

“Our current study identifies a novel mechanism that underlies the impact of acute stress on working memory, a cognitive process depending on glutamate receptor-mediated excitatory signals in prefrontal cortex circuits.”

The researchers state that the study may aid in a getting a better perspective into the complex actions of stress in human beings in varying situations.

The study appears in the on line edition of Proceedings of the National Academy of Sciences.