Stress and Memory: An Update

Salvador Dali Persistence of Memory at Stresshacker.comStress can interfere with the functioning of memory by either augmenting the impact and persistence of the recollection of an event, or by diminishing both. A recent article by Schwabe et al. (2012) summarizes and updates the most recent findings on the effects of stress on memory. Their research concludes that the timing of the exposure to the stressor is crucial in determining whether memory is improved or impaired. Timing may explain why there are stressful situations in which we are unable to retrieve critical information that we have learned prior to the stressor, e.g. an important phone number or address. In contrast, experiencing stress at the same time as we participate in certain embarrassing, shameful, or frightening events can cause a dramatic enhancement of memory formation.

Schwabe and colleagues examine and attempt to integrate two models of how stress may alter memory processes, the “vertical” model (the mechanisms of stress on memory) and the “horizontal” model (the changes in stress effects on memory over time.)

The vertical perspective implicates principally the action of glucocorticoids (GC) and noradrenaline on the basolateral amygdala. In a typical stress reaction, the hypothalamus activates the hypothalamic-pituitary-adrenal (HPA) axis in response to input from several other brain regions and the sympathetic nervous system (SNS). Through the portal blood system, corticotrophin releasing hormone (CRH) and vasopressin flood the pituitary gland, which trigger its secretion of adrenocorticotropic hormone (ACTH). In response to ACTH release from the pituitary, the adrenal glands secrete glucocorticoids (GCs), of which cortisol is the principal component. GCs, which are lipophilic (fat-loving) steroid hormones, enter the brain relatively easily and can exert their excitatory effect in multiple regions throughout the brain. These effects are often mediated through the binding to the two receptors for the hormone: the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptors differ in their affinity for cortisol (with the MR having a much higher affinity) and also in their localization in the brain. In addition, GCs can exert nongenomic effects (occurring rapidly and acutely) by influencing ion channels or neurotransmitter receptors at the membrane level. It is important to note that CRH, vasopressin, and ACTH can, on their own, influence cognition. When released in concurrence with a stressor, they can have an almost instantaneous effect on memory processes.

The horizontal perspective suggests that the memory of an event or cognition is enhanced when new information is acquired during the stressful situation, whereas the memory process is impaired for information that was acquired prior to or after the stressful situation. In these situations, the flood of GCs acutely enhances memory consolidation of emotional arousing material, while significantly impairing memory retrieval. At the moment of greatest stress, the memory of a significantly stressful event is instantaneously etched into the memory banks in vivid and abundant detail. The recollection of a sometimes important and well-known piece of information is inhibited. It is as if the whole of our attention is absorbed, or mobilized, toward the assessment of the threat presented by the stressor and in the formulation of a reaction to it. The excitatory hormones cursing through the blood system rapidly arouse the nervous, cardio-circulatory, respiratory, and endocrine system. There is no time or resource available for other activities that are not related to the defense of the organism against the perceived (or real) threat of the stressor. Included in these “secondary” activities that are postponed as non-critical is memory retrieval of old information.

Other important findings highlighted in this article are the effects of stress on the striatum, a brain structure that was originally associated with motor control but that is now receiving increased attention as one of the loci of mnemonic function. Secondly, memory is affected by stress not only in terms of its quantity, but also its quality. Lastly, the authors cite important research conducted in the last decade which points to the effects of maternal stress during pregnancy or early childhood stress as harbingers of an individual’s impaired performance as an adult in high-stress environments.

The article concludes with several important questions, which provide an indication of the limits of current research in explaining important aspects of memory formation. For example, it remains difficult to understand how the same neurochemicals can exert opposite effects on the same brain structures, or how individuals in similar situations exhibit such differing recollections of the same event, and other similarly unexplored mysteries. These limitations do not detract from the thoroughness and relevance of this article.

The Seasonal Stress Buster

Oh, for the good old days when people would stop Christmas shopping when they ran out of money. –Author Unknown

I’m not sure where this year has gone, but all of a sudden Christmas is here. With so much going on at this time of year it’s quite common to feel stressed and rushed off our feet. If you’re juggling a million different things, here’s a brilliant time management technique which might help.

I wish I could say that I thought of this technique myself, but must give credit to Time Management guru Mark Forster. According to Mark, we work much more effectively when we do things in short, concentrated bursts. This is definitely true for me. If I sit down at my computer to check emails I’m very likely to still be there an hour later. But if I know I’ve only got 15 minutes to do the task I’ll be considerably more productive.

So, using this principle, if you’ve got several jobs to do, write them down and assign each one a time limit (from 5 – 30 minutes). Set a kitchen timer, start the first task and when the timer goes you must stop and go onto the next one. Again set the timer for the allotted time, work on the task until the timer goes off and move on to the next. Don’t worry if the task isn’t finished; you can go back to the beginning once you’ve worked your way through the list.

This is the best time management technique I know and it works equally well when you have a big chunky job to do. Get stuck into the job for half an hour, have a break/do something else for ten minutes, then go back to it.

At this time of year, with so many demands on our time, this technique will help you to get everything done in the shortest time — leaving you more time to enjoy the seasonal activities.

2012 has been an unusually challenging year for many of us and so as it draws to a close I wish you a healthy and Happy Christmas and all good things in the New Year.

Annabel Sutton
ICF Professional Certified Coach
Author of 52 Ways to Transform Your Life

Connect with Annabel on LinkedIn: http://uk.linkedin.com/in/annabelsutton. Book a FREE Coaching Consultation with Annabel. Find out more about Life Coaching.

Sleep More, Stress Less, Live Longer

iStock_000007980637XSmall People who are sleeping less than six hours a night are at risk for more cardiovascular events, more likely to develop diabetes, and more likely to die sooner, according to a recent study. People who sleep at least seven hours per night have better immune systems, less stress and lower body weight.

Sleep deprivation can be dangerous not only to one’s health but also to that of others around us. US statistics from the Department of Transportation estimate that 20% of drivers doze off regularly at the wheel, while the National Highway Traffic Safety Administration estimates conservatively that, during an average year, “drowsy driving” causes 100,000 automobile wrecks, 71,000 injuries and 1,550 fatalities. These staggering stats are supplemented by data from the US military, surveys of truck drivers, shift workers, couples, medical students. All pointing to one simple fact: if we can’t sleep, sooner or later the body will react negatively, sometimes with tragic consequences.

Physical Threats to Sleep

TIME

Sleep time is under attack from many sources. First and foremost, our work and leisure schedules allow too little time for sleep. While this may seem like a no-brainer and suggest that there is a simple remedy (just allocate more time to sleep!), the problem of sleep scheduling appears to be more complex and somewhat intractable. The reason for this may be below the surface and may be due to a change in how we perceive sleep. While we continue to proclaim its virtues and benefits, at least out loud, aren’t many of us secretly wishing that we could simply do away with sleep altogether?

LIFESTYLE

Many people have a more complex lifestyle that demand an ever finer slicing of time slots. Time is a finite resource that can be neither reduced nor expanded, which forces a setting of priorities. And here is the heart of another problem: for many people sleep is no longer a priority. In fact, it is often considered a time waster that can keep us from other, more important activities.

ENVIRONMENT

Another potential problem is that sleep is not as undisturbed as it once was, in environmental terms. There is the interference of noise, either unwanted or induced (as in keeping music, TV or noise-makers on to “help us fall asleep”). There is the interference of artificial light, or rather too much of it, which we have grown so fond of and subconsciously seek. There is the interference of artificially controlled air, which may be either too dry or too humid or too hot and all variables in between. The A/C or fan or heater is on, adding to noise. One just can’t win the environmental battle in the bedroom!

CHEMICALS

What we eat, drink, smoke, snort, inject, wear, rub or apply can interfere with sleep. Medications, self-care products and nutritional practices that are designed to address specific issues may be very effective, but can cause side effects that have a negative impact on our ability to sleep. These modern chemical helpers may be (or perceived to be) necessary to fix a specific issue, and thus take priority over side effects that may include a negative impact on sleep.

Psychological Threats to Sleep

Individual situations vary greatly, but the following are probably perceived by most sleep-deprived individuals.

STRESSORS

Our own individual and habitual way of reacting to stressors large and small may have a significant impact on sleep. By suppressing a necessary release of emotion in the face of a stressor, we may temporarily “bury” feelings, thoughts, and impressions that find a way of resurfacing later, just when we are trying to relax and fall asleep.

INADEQUATE COPING

Our inability to cope with significant stressors in a timely and effective way may impact our ability to sleep. Not all stressors can be taken care of, i.e. eliminated, in a swift and painless way. Many do linger on, while we are looking for the right solution. Many stressors can be reduced in intensity or frequency. Others can be tolerated or ignored, after a suitable period of adjustment. Some stressors are of such magnitude and impact that we can only resolve them by removing ourselves from their influence, i.e. by moving away. Whatever the case may be, our coping response to stressors is multidimensional along time, frequency, and severity scales, and sleep deprivation is often a byproduct of the coping process.

ALLOSTATIC LOAD

Our stress level may rise and remain at high levels throughout the day, including the time when we’d need it to be lower so that we can fall asleep. This phenomenon is called our individual allostatic load. Allostatic load is the piling up of stress reaction upon stress reaction, without resolution, and without a return to normal arousal levels. Over time, this situation has the effect of permanently raising the set point of our stress level, whereby it is very difficult if not impossible to turn it down at will when we are trying to relax and fall asleep.

The Path to Better and Longer Sleep

There are so many sleep aids available nowadays, it’s a wonder we can even stay awake!  Fact is, most of them don’t work. The ones that do work do so by simply knocking us unconscious via powerful chemical agents. Is that real sleep? Many people report that it does not seem to refresh and restore, and chemically-induced relaxation simply bypasses the issues and turns the switch off. When we reawaken, these issues return and require another dose to be shut off again. This cycle repeats and repeats. Is that the way to fix this and get some rest?

The fix must start with identifying the stressors that keeps us from falling or staying asleep. Each night when you are trying to go to sleep, make a list of the thought-items that are swirling around in your mind. Do so for 7 nights. On the 8th day, look at the 7 lists, group thought-items together into issues. Now, you know within a good approximation what issues are keeping you awake.

Next, address the stressors so that they will no longer keep you from sleeping. Look at your issues and group them into three categories: the ones you can resolve, the ones you need to adapt to, and the ones you can ignore. Call upon your problem-solving skills and address the issues that can be resolved during the day. When you get to bed, intentionally stop trying to solve problems. Give yourself a break until the next day.

What about the issues I can’t resolve?  Here’s a radically different piece of advice: don’t even try to resolve them now. Accept that they cannot be resolved at 10pm or 2am. And, even more importantly, accept the idea that working on these issues will make your sleep more difficult and that it’s an exercise in futility. Instead of becoming more and more frustrated and agitated because you can’t relax, choose not to acknowledge your situation and don’t fight its impact. This may be the time to read a good book, go get a cup of herbal tea, listen to the crickets, make your list, jot down a few ideas about the screenplay, instead of tossing and turning and trying in vain to go to sleep.