Why Stress Jumbles the Brain

Last week, I wrote about how a greater capacity for working memory actually hinders children with math anxiety. In short, their large mental capacities allows their brains the luxury of worrying, which detracts from their other mental calisthenics.

Maybe they just need to be stressed out before their test.

A new study from the University of Wisconsin recently revealed why stress detracts from our working memory. The ability to remember recent information and recall it for manipulation and use resides completely in the prefrontal cortex. By studying how the neurons work during a maze test both with and without external stressors, researchers were able to show what happens in a rat’s brain to cause the loss of working memory.

Craig Berridge, University of Wisconsin professor of psychology, and David Devilbiss, scientist in the University of Wisconsin’s Laboratory of Neurophysiological Modulation and Behavior, monitored the prefrontal cortex of rats as they maneuvered through a maze to earn chocolate chips. When functioning properly, the rats’ neurons fired at regular intervals in order to keep recent information fresh in their memories. Without these constant refreshers, the information would be lost.

Then, the duo added some stress to the situation. While trying to score their chocolate fix, a loud blast of white noise interrupted the rats’ train of thought. But rather than suppressing the refresher firings, the stress caused the prefrontal cortex to go into a bit of overdrive, causing them to fail in their task of retaining the information needed to complete the maze.

Rats without the stressing noise successfully completed the maze 90 percent of the time, while those under stress only got their chocolaty reward 65 percent of the time. Recordings of the electrical activity of prefrontal cortex neurons in the maze-running rats showed these neurons were unable to hold information key to finding the next chocolate chip reward. Instead, the neurons were frenetic, reacting to distractions such as noises and smells in the room.

It seems a little counterintuitive, but the loss in working memory actually is the result of your brain working too hard, rather than not hard enough. Or is it that your brain isn’t working hard enough to suppress those additional nerve firings, as another previous post might have you believe?

Who knows.

The only thing we know for sure is that the brain is wonderfully complex, and a fascinating place for research and discovery.


About bigkingken

A science writer dedicated to proving that the Big Ten - or the Committee on Institutional Cooperation, if you will - is more than athletics.
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