Working Memory May possibly Be Improved By Short Stressful Events no comments
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Experiencing chronic anxiety day after day can produce wear and tear on the body physically and mentally, and can have a detrimental effect on studying and emotion. However, acute anxiety — a short stressful incident — might enhance studying and memory.
Researchers at the University at Buffalo have shown, in trials using rodents as an animal model, that acute stress can generate a useful effect on learning and memory, by way of the effect of the anxiety hormone corticosterone (cortisol in humans) on the brain’s prefrontal cortex, a crucial region that controls studying and emotion.
Specifically, they demonstrated that acute tension increases transmission of the neurotransmitter glutamate and improves working memory.
“Stress hormones have each protective and damaging effects on the body,” said Zhen Yan, professor of physiology and biophysics at UB and senior author on the study. “This paper and other people we have within the pipeline clarify why we need to have anxiety to perform greater, but don’t need to be stressed out.”
The study appeared July 20 within the on-line edition of Proceedings of the National Academy of Sciences and is going to be published in an upcoming print version of the journal. Eunice Y. Yuen, Ph.D., UB research assistant professor of physiology and biophysics, may be the first author on the study.
To test the impact of acute tension on working memory, Yan, Yuen and colleagues trained rats in a maze till they could complete it properly 60-70 percent of the time. When the rodents reached this level of accuracy for two consecutive days, half had been put via a 20-minute forced swim, which served as acute tension, and then had been put via the maze once more.
Results showed that the stressed rats produced considerably fewer mistakes as they went by means of the maze each 4 hours soon after the stressful knowledge and one day post-stress, compared towards the non-stressed rats.
To decide if the corticosterone neuropathway was responsible for the improved memory, as they proposed, researchers injected one group of rats just before the stressful forced-swim with a medicinal compound that blocks the pathway, and injected another group with saline. Outcomes showed that the saline group, in which the corticosterone neuropathway was not blocked, performed better inside the maze than the blocked group.
The researchers also determined that the stressful encounter did not increase depression or anxiety-related behavior in the animals.
“It is known that anxiety has both positive and negative actions inside the brain, but the underlying mechanism is elusive,” said Yan. “Several crucial brain regions involved in cognition and emotions, including the prefrontal cortex, have been identified as the main target of corticosteroid, the main pressure hormone.
“Our present study identifies a novel mechanism that underlies the impact of acute anxiety on working memory, a cognitive approach depending on glutamate receptor-mediated excitatory signals in prefrontal cortex circuits.”
The investigators have expanded this analysis in a number of directions. In a paper at present under evaluation, they have identified the key signaling molecules that link acute tension to the enhancement of glutamate receptors and working memory.
“In addition,” noted Yan, “we have found that chronic stress suppresses the transmission of glutamate within the prefrontal cortex of male rodents, which is opposite towards the facilitating effect of acute tension, and that estrogen receptors in female rodents make them more resilient to chronic pressure than male rats.
“All these studies ought to bring new insights into the complex actions of tension in various circumstances that may be applicable to humans in the future,” she stated.
Wenhua Liu, Ph.D., postdoctoral associate, and Jain Feng, Ph.D., associate professor, each inside the UB Department of Physiology and Biophysics, are co-authors on the study, in addition to Ilia N. Karatsoreos, Ph.D., and Bruce S. McEwen, Ph.D., from The Rockefeller University.
The investigation was supported by grants from the National Institutes of Well being to Yan plus a National Alliance for Research on Schizophrenia and Depression Young Investigator Award to Yuen.
Source:
Lois Baker
University at Buffalo