Splintered by Stress: The Good and Bad of Psychological Pressure

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In Brief

Stress and Memory

Stress hormones such as adrenaline and cortisol can either facilitate or impair memory, depending on when these hormones are released.

Stress hormones may affect memory by strengthening or weakening the connections between nerve cells in the brain.

Drugs that mimic cell-adhesion molecules, which bridge the gaps between nerve cells, may help restore memory in people with stress-induced cognitive disorders.

A needling twinge in the torso or a tense interaction with a boss is all you need to get your nerves on edge. The bills are piling up and?of course?your spouse is on your case about them. You feel as if an extra weight is pressing down on your mind.

The all too familiar sensation of stress can preoccupy your thoughts, narrowing attention to the sphere of your concerns. But its effects do not end there?stress also causes physical changes in the body. In a stressful situation, alarm systems in the brain trigger the release of hormones that prepare you to fight back or flee the scene. Among other results, these chemicals may boost blood pressure, speed up heart rate and make you breathe faster. They may also affect your ability to learn and remember things.

Think back on the tests you took in school. Even when you crammed like crazy, your performance on exams may have left something to be desired. Maybe key pieces of knowledge simply escaped you?until they came to mind, unbidden, several hours too late. One possible explanation for this phenomenon is stress: your anxiety may have impaired your recall.

That reasoning sounds simple enough, but it turns out that the effect of stress on ?memory is surprisingly nuanced. Studies have shown that under certain circumstances, psychological pressure may actually improve recall?but not necessarily of the facts you were hoping to summon to pass the class. People who have trouble remembering information during a test often have strong recollections of the frustration and embarrassment they felt at the time. Emotionally charged experiences?whether positive or negative?remain extraordinarily well anchored in memory. Recall your most vivid experiences from last year. Most likely they were accompanied by particular joy, pain or stress.

Researchers have long struggled to untangle the role of emotions and other factors in the encoding of stressful memories. In the past few years we and other researchers have come to the conclusion that the effects of stress depend on its timing and duration: the details of the moment make a big difference as to whether the stressor enhances recall or impedes it. And the memory boost happens for only a relatively short period?beyond a certain window, all stress becomes deleterious. Understanding the distinctions between different physiological responses may lead to new treatments that can reduce or even reverse the debilitating impacts of stress on memory.

Muddled Memories
In 2005 Sabrina Kuhlmann of the University of D?sseldorf in Germany and two colleagues conducted an experiment to test the effects of stress on memory. They wanted to know whether stress affects recall of either emotionally charged or neutral material. The three researchers had 19 young men memorize a list of 30 words that had either positive, negative or neutral associations. The next day the psychologists subjected some of the men to the Trier social stress test, a procedure that puts participants through a series of stressful experiences, including making a job-application speech to a panel of three people playing the role of company managers and then performing some mental arithmetic for the panel. A short time afterward, the men were asked to remember the words they had learned the day before. The result: stress reduced the number of emotionally charged words that the men were able to recall, although it did not affect their memory of neutral words.

Earlier experiments had found that administering the stress hormone cortisol can impair our ability to retrieve memories, but the D?sseldorf study was the first to show that stress itself can have this effect on humans, presumably by triggering the release of cortisol and other hormones. The finding may help explain why people who are feeling stressed?during an exam or a job interview, for example?sometimes have trouble remembering important information. The results also suggest that emotionally arousing material may be especially sensitive to the memory-altering effects of stress hormones, perhaps because these hormones activate the amygdala?a brain structure that plays a critical part in processing emotions.

Source: http://rss.sciam.com/click.phdo?i=145ef4a2c80c2f0886338a8278ca693b

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