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Showing posts with label brain. Show all posts
Showing posts with label brain. Show all posts

Monday, August 19, 2013

Learning To Be Stressed

People are constantly exposed to stressful situations. These may be physical (like participating in marathons, being exposed to radiation, and, perhaps surprisingly, exposed to sedatives or anesthetics). But stress can also be mental, wherein we become anxious and worried over certain events, existing or anticipated. Whether physical or mental, stress activates a brain network involving most directly the hypothalamus, the pituitary gland, and the adrenal cortex to release stress hormones. Such hormones include several cortisone-like compounds called glucocorticoids, and the most prominent one in humans is cortisol.

Glucocorticoids have profound effects on both body and brain. Regulation of glucocorticoids is accomplished by the brain, and learning experiences have profound effects on this control system. Most of what was initially known about glucocorticoids was their effect on the body. I had the great thrill of visiting the pioneer in this field, Hans Selye, in his laboratory complex at the University of Montreal. He had a whole room full of medals, awards, and honorary doctorate diplomas. He won practically every research accolade there was, except the Nobel Prize, one of several grievous slights by the Nobel committee. Dr. Selye wrote an autobiography for my book, Discovery Processes in Modern Biology.

Effects on the Body


Selye’s research led him to formulate the widely accepted concept of the glucocorticoid system as accounting for a “General Adaptation Syndrome,” which basically explained how the brain and body respond to stress. He discovered that glucocorticoids are “Goldilocks” compounds. That is, a little doesn’t do much, a lot is damaging, and intermediate levels are “just right.”

A moderate amount of cortisol is what is normally released every morning before you awaken. By the way, this is the reason surgeons want to operate early in the morning. This release helps prepare the body for the day’s activities by mobilizing blood glucose, typically by breaking down fat and, if needed, protein stores. Glucose is especially important for the brain, which has huge demands for energy, and which can only burn glucose for energy. Neurons are energized and memory ability is enhanced. Another useful thing cortisol does is to reduce the release of cellular chemicals that cause inflammation.

However, the hormone also inhibits systems that channel resources for growth and reproduction, impairs bone formation, and inhibits the immune system. Basically, the idea is that glucocorticoids help brain and body to respond to temporary emergencies by assigning lower priority to other physiological needs.

The rub comes when stress is prolonged. Selye discovered that the beneficial adaptation to temporary stress cannot be sustained in chronic stress. The system becomes exhausted and control breaks down.[1] Under chronic stress, body muscle mass decreases because the system has been breaking down proteins in order to generate energy. Inflammation bathes cells in toxic chemicals. Infections increase because the immune system has been compromised. In obese people, glucocorticoid levels cumulatively increase in fat cells, increase fat deposits still further, and increase the likelihood of type 2 diabetes and cardiovascular disease.[2]

Effects on the Brain


In the case of brain, persistent high levels of glucocorticoid often causes depression. Memory ability is impaired. Brain degeneration and cognitive decline accelerate. Many neurons are actually killed. What I want to stress here is that chronic high levels of cortisone change the neural circuitry that regulates its release. In other words, the brain learns a new way of functioning if constantly bathed in high levels of cortisone.

Effects of Learning


Few people make the connection between glucocorticoid control and learning. The neuronal circuits that control hormone secretion learn from stressful experience, just as all neurons learn from whatever they experience. What neurons in the cortisol control circuit learn in chronic stress is that the usual controls can’t work any more.

A typical response to a repeated stress of a certain type (for example, constant quarrels with a spouse or repeated job failures) can be habituation. It’s like “tuning out.” Repeated exposure to the same stress teaches the neurons to stop responding as much as usual. Thus, there is less of the benefits that glucocorticoids provide.

At the same time, the hormone control system becomes hypersensitive to other stresses, especially unpredictable or especially severe stresses. The control system learns to over-react to everything other than the stress to which it has habituated. Now, the damaging effect of too much glucocorticoid becomes pervasive, both for body and brain.

Whether the brain learns stress-coping strategies depends on conscious over-ride of hyper-active responses to stress, because the neural system (the limbic system) that operates our emotions also regulates the glucocorticoid control system. We can not only reduce excessive glucocorticoid but also teach our brain better ways to deal with stress by doing the following:

·         Simplify and organize our life,
·         Do one thing at a time and finish it,
·         Find pleasure in the little things,
·         Learn to have a more positive attitude,
·         Laugh and be happy,
·         Suppress anxiety,
·         Be more rational and less emotional,
·         Develop supportive social relations,
·         Reduce exposure to stressors. 

For more on learning and memory in general, see Dr. Klemm’s new book, Memory Power 101, Skyhorsepublishing.com.


Photos courtesy of FreeDigitalPhotos.net, by Artur  84 and Ambro

[1] Herman, James P. 2013. Neural control of chronic stress adaptation. Frontiers in Behavioral Neuroscience. August 8. Doi: 10.3389/fnbeh.2013.00061

[2] Vogelzangs N. et al. 2009. Late-life depression, cortisol, and the metabolic syndrome. Am J Geriatr Psychiatry. 2009 Aug;17(8):716-21. doi: 10.1097/JGP.0b013e3181aad5d7.

Monday, September 10, 2012

10 Ways to Slow Mental Decline with Age


Deterioration of the brain usually sneaks up on us. By the time we realize it, it may be too late. As we get older, we more frequently start asking questions like “Where did I put the car keys?” “What was it I was supposed to get at the store?” “What’s your name again?” Most of us have had to ask questions like this, and it seems to happen more often as we get older. We can’t turn back our biological clock, but there are things seniors can do to reduce the rate of their mental decline. The time to act is while you are still relatively young.

 I have made a career out of studying brain and behavioral research literature, and I know some of this research is relevant to everyday memory problems. I have summarized these findings in my new book, Memory Power 101 (298 pages, $14.95, Skyhorse.com), and keep readers up to date with my blog (thankyoubrain.blogspot.com).

As people age, beginning in early middle age, many of them experience a brain deterioration that progresses silently over the next decade or two, sometimes ending in devastating senility. Behaviorally, aging can cause your reflexes to slow. You walk and act slower. You even talk slower. Our memory starts to fail, especially the short-term form of memory ability that is so crucial for learning new things.

Now that bran-scan technology is widely available, physicians have discovered that the brain usually shrinks as people get older. The shrinkage increases the space between the brain surface and the skull. The cavities that hold cerebrospinal fluid get bigger. Nerve tracts in the brain shrivel, even leaving gaping holes in the brain. The “dendritic trees” shrivel, and these have major consequences because dendrites are the parts of neurons that form the contact points, and their loss reduces brain circuitry. You may also lose 40% or more of your dopamine neurons, and that may lead to Parkinson’s disease

For aging individuals, the challenge is to reduce the rate of their decline. This has created a growth anti-aging industry focused on vitamins and supplements, fad diets, gym facilities, mind training programs.  The good news is that some of these things work, if they are begun while people are in early middle age. Given that our country now has so many baby boomers in the over-50 category, it seems useful to summarize some things people can do to prevent or slow memory decline as they age. I particularly like the summary at this site.

Here is an expanded list of things I think are especially important for people entering middle age.

1. Get better organized. Many things we try to remember do not have to be remembered if we get better organized. Car keys, for example, should ONLY be in the car, your pocket/purse, or the same place in your house. Ditto for many other objects, such as purse, hat, glasses, etc. Life is a lot simpler when you have a place for everything, with everything in its place. Habit relieves the memory.

2. Make a special effort to pay attention, concentrate. Research shows that aging reduces a person’s ability to focus and pay attention. This also means that seniors have to work harder at filtering distractions, such as when we open the refrigerator door and forget what we are looking for because we thought of something else before we opened the door. New learning has to be consolidated to form lasting memory, and this takes a little uninterrupted time and conscious rehearsal right after you learn it. Seniors are especially susceptible to having temporary memories wiped out by distractions.

3. Challenge yourself mentally. Seek out new experiences, an active social life, and mental demands such as learning a new language, playing chess, or getting an advanced college degree. Learning new things always has the benefit of making you feel good about yourself, and this is especially true for seniors who accomplish things most people think they can’t do. By the way, there is abundant research literature showing that a lifetime of vigorous learning helps stave off Alzheimer’s disease.

4. Reduce Stress. Acute stress helps you be alert, pay attention better, and increase your chances of remembering what is happening at the time of stress. But chronic stress, whether caused by the same or different stressors, clearly disrupts memory formation and recall. Chronic stress and the hormones it releases can actually kill neurons and shrink the brain (which shrinks with age anyway, and only gets worse with chronic stress).

5. Eat foods with vitamins and anti-oxidants. Make certain you have a balanced diet. Supplements usually won’t help memory unless you have a nutritional deficiency. But even with a good died, adding vitamins C, D, and E can be helpful. Several research studies indicate a memory benefit from eating foods loaded with anti-oxidants. Blueberries (especially on an empty stomach). Another potent anti-oxidant is an ingredient in red wine, resveratrol, but there is no way you could drink enough; however, resveratrol supplements are now on the market. There is also suggestive evidence for memory improvement from omega-3 fatty acids and folic acid. Pharmaceuticals to improve memory are in the works, but you may have to wait quite a while before research shows which ones really work.

6. Don’t get obese, especially in middle age.
Confocal microscopy reveals that every added pound of fat adds approximately one mile of capillary tubing. Obviously, all these added vascular tubing puts a strain on the heart. A diet that produces new fat may well contribute to hardening of the arteries, which in turn compounds the added workload on the heart. People who are obese commonly have high blood pressure and other risk factors involving metabolism.

Obesity is a common cause of diabetes, which adds its own toll on blood vessels and the heart, as well as on nerve cells. No wonder then that obese people may develop mental deterioration. The problem may be worse in women. The more a woman weighs, the worse her memory. No, I am not a chauvinist pig. This claim comes from actual research —by a woman, no less. Diana Kerwin and her colleagues at Northwestern University studied 8,745 ages 65 to 79 and found that for every one-point increase in body mass index, the score on a 100 point memory test dropped by one point.

A likely cause of mental decline in most people is diminished blow flow in small vessels that are easily plugged by cholesterol and lipids or ruptured by high blood pressure. These “mini-strokes” are probably quite common as we age, and though they go undetected, they cause a cumulative damage which progressively affects our behavioral and mental capabilities. Brain cells are among the most metabolically active of all cells: they constantly fire electrical pulses and secrete relatively huge amounts of secretions (neurotransmitters). The brain consumes about 20% of all the body’s oxygen, even though it only ways about 3.5 pounds.

When brain cells do die or are damaged for any reason, healthy neurons are assaulted by inflammatory chemicals, like cytokines, that are released by the brain’s immune cell system. Fat deposits not only stress the heart, they also increase the amount of cytokines, which are hormones that can cause inflammation. Brain inflammation is also commonly caused by infections such as colds and flu and by diets deficient in anti-oxidants.

7. Exercise the body. Though exercise doesn’t do much to cause weight loss unless you are a marathon runner of tennis singles champion, it has many other benefits (improved circulation of blood to the brain, improved levels of HDL cholesterol) that can directly benefit memory and cognitive function. Vigorous aerobic exercise can improve your circulation and perhaps blood flow in the brain. But there also seem to be memory benefits from exercise that is independent of blood circulation. We don’t know why. Maybe relief of stress and improved mood are factors. We know that positive emotions help memory, but for unknown reasons.

8. Exercise the memory. The more you make an effort to memorize, the easier it seems to get. Practice the memorization tricks used by “memory athletes” that I describe in my book. I describe in my book specific image-based systems (“peg systems”) for performing astonishing memory feats, such as card counting, remembering long strings of numbers, and remembering the gist of what is on every page of a magazine or book.

9. Get plenty of sleep. Many studies show the brain is processing the day’s events while you sleep and consolidating them in memory. This kind of “off-line” rehearsal occurs just for the learning experiences on the day of sleep. Naps help too! How’s that for good news?

10. Believe in your brain’s ability to get better. Of course genes and luck have a lot to do with how well one ages mentally. But genes and luck seem to be more common in people who do the nine things mention above. Too many seniors buy into the popular myth that old dogs can’t learn new tricks. They resign themselves to defeatism. But the bottom line is that, unless you have Alzheimer’s disease, you can improve your mental sharpness. Getting older has enough frustrations. Don’t compound them by tolerating mental decline. Enjoy an improved brain. 

Thursday, October 15, 2009

Multi-tasking May Damage the Brain

We older adults tend to be awed at how young people today can multi-task. They seem to text message on cells phones, watch TV, listen to music, play a video or computer game, carrying on a conversation, and maybe even study their school lessons all simultaneously with apparent ease. Many adults, and even teachers, encourage multi-tasking because they think it is good stimulus for the brain and that learning how to multi-task is a useful skill. But I have already identified many research reports that show multi-tasking to impair formation of memory. Multi-tasking prevents the focused attention and reduction of distractions that are necessary for good memory.

Now there is a research report suggesting that the brain itself may be damaged by multi-tasking. Investigators at Stanford University gave questionnaires to their subjects to identify how much multi-tasking each person did. Nineteen subjects were "heavy multi-taskers" and 22 were "light multi-taskers." Comparison of how these two groups in thinking control tasks revealed that heavy media multi-taskers were more susceptible to interference from irrelevant environmental stimuli and from irrelevant representations in memory.In other words, they were more distractible. Then researchers tested the subjects for ability to filter relevant information from the environment and from their memories and to switch thinking tasks. A typical filtering test, for example, required subjects to detect changes in red triangles on a screen while ignoring blue triangles in the same pictures.

The heavy multi-taskers performed worse, even though their experience and presumed skill at multi-tasking should have made them more effective at these tasks. The heavy multi-taskers believed that they were good at multi-tasking, when in fact they were bad at every task that required multi-tasking.

It is not clear how much physical deterioration has occurred in brain from chronic multi-tasking. But at a minimum, multi-tasking is likely to reduce the brain's ability to develop concentration and thinking skills. Why do I suggest diminished thinking skills? Thinking is done with an orderly progression of items in working memory. Multi-tasking bombards working memory with scrambled and unfocused information and probably keeps the brain from learning how to optimize focus and orderly sequencing of thoughts through what I call the brain's "thought engine."

Source: Ophir, E., Nass, C. and Wagner, A. D. 2009. Cognitive control in media multitaskers. Procedings of the National Academy of Science. Aug. 24. doi: 10.1073/pnas0903620106