Sunday, November 10, 2013
It’s normal to get depressed. Let’s face it, a lot of life experience IS depressing. Depression that is severe enough to be considered a clinical malady is a state that persists for long periods. It’s not the initial depression that is the problem, but rather its sustained nature.
So, the issue is what sustains the depression. I contend that continual rehearsal of negative emotions, which can be done explicitly or implicitly, is the driver of clinical depression. I don’t know if psychologists agree or not, but as a neuroscientist I know that rehearsal of thoughts and feelings strengthens the mediating synapses and circuits.
Obviously, consciously rehearsing bad events and our depressive response will help to cement depression in neural circuitry. But even implicit rehearsal can have the same effect. This being the case, it seems important to focus on the triggers that activate recall, explicit or implicit, of stored representations of depressed feelings. Bad events and their associated feelings are stored in memory. As long as such memory is stored and not activated in recall, little harm is done. But environmental and mental cues can dredge depression from its hidden stores. Repeated retrieval is what makes depression pervasive and persistent.
So, it would seem important to focus on ways to block the retrieval cues. Yet, part of the problem is in recognizing what these cues are, as they are frequently buried do deep in memory that the cues are no longer available for explicit recognition. Yet, subconsciously, the cues still wrench the sadness from memory storage.
One solution that sometimes works is to change environments. Even if you don’t know what the depression cues are, you know they can somehow be embedded in the current environment and lifestyle. Maybe the problem is with some of the people you run around with. People who drag you down are not all that hard to spot. Avoid them. Maybe the problem is with your career or work environment, which has saddled you with depressing experiences from time to time. Staying in that environment assures that depression triggering cues will be encountered again.
It is not always feasible to change environment or lifestyle. You can’t abandon those you love just because
Common experience and a great deal of formal research have shown the usefulness of “happy thoughts” as a way to boost positive mood. Here, the trick is to enhance recall of the buried memories of happy experiences. The same neural mechanisms involved in rehearsal and recall of depressing experiences are involved. But, you can’t be sad and happy at the same time. Thus, triggers that recall happy experiences do so at the expense of triggers that would trigger depressive feelings.
Recent research emphasizes the importance of memory cues as therapy for depression. In this study, clinically depressed patients were asked to recall 15 positive memories. Patients in one group, the controls, were asked to rehearse these positive experiences by grouping them according to similarities. Patients in the experimental group were taught to use a mnemonic technique to rehearse the positive memories. This technique, the ancient “method-of-loci” method, entails associating a mental image of an item to be remembered to an image of a well-known physical location. For example, to remember a grocery list, you might use location of objects in your car. You might picture a banana in your side view mirror, apples on the steering wheel, bread on the dashboard, cereal in the rear-view mirror. As you drive to the grocery store, you rehearse the items in terms of their mental images and locations within the car. There are many powerful permutations of this method that I explain in my recent book, Memory Power 101.
Results of the experiment showed that both memorization methods were equally effective when recall was tested right after the training. But a week later, experimenters made a surprise phone call to each patient and asked them to recall the happy thoughts again. This time, clearly better recall occurred in the patients who had used the method-of-loci method. If we can generalize these results, it means that patients can alleviate their depression if they train their brains to be more effective at remembering positive events. This can be done at any stage of life, as we all have a past and there typically were some good moments in that past. Whether you use a method-of-loci method to remember happy times or some other memory device, your life should be more satisfying and less depressing when you consciously train your brain to remember the good times.
Dalgleish, T. et al. (2013). Method-of_Loci as a mnemonic device to facilitate access to self-affirming
Sunday, November 03, 2013
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 women ages 65 to 79 and found that for every one-point increase in female body mass index, the score on a 100 point memory test dropped by one point.
The problem was greatest in women who had put the weight on around the hips, which is fairly typical for weight gain in women. Nobody knows why this is so. Fat deposits may increase the amount of cytokines, which are hormones that can cause inflammation. In a couple of earlier columns I explained how body inflammation, from sore joints or sore throat, for example, can trigger inflammation in the brain. I explained that brains can get inflamed too, irritated from the release of cytokines and other toxins from the brain’s immune cells in response to inflammation. In both genders, these toxins diminish mental capabilities, especially memory. Remember, everything the brain does affects memory (and everything affecting memory affects the brain).
Another obvious possibility is that excess weight often creates vascular problems, and everybody tends to have a problem with circulation in small arteries as they get older. Excess weight is a risk factor for stroke, as well as Alzheimer’s Disease.
This finding about memory loss is just one of many good reasons to lose weight. There are only two ways to lose weight: eat fewer calories and exercise more. Though exercise doesn’t do much to cause weight loss, it has many other benefits (improved circulation of blood to the brain) that can directly benefit memory and cognitive function.
It is not surprising then to learn of recent studies showing that losing weight can improve thinking and memory, in both men and women. John Gunstad, at Kent State University, compared attentiveness and memory test scores in 150 overweight subjects 109 of whom who had bariatric stomach by-pass surgery and 41 controls who did not. Those who lost weight because of gastric bypass surgery showed mental function improvements within 12 weeks after surgery. Those without hypertension improved more than the bariatric patients who had hypertension. Memory performance of the obese controls actually decreased over this period. Gunstad has a U tube video on his work at www.youtube.com/watch?v=gsFP2zAkStU.
Of course bariatric surgery is not without its problems. This surgery can lead to Wernicke's encephalopathy, a condition associated with thiamin or vitamin B1 deficiency. Symptoms of Wernicke's encephalopathy include loss of short-term memory, vision and muscle coordination. Presumably, vitamin supplements prevent this problem.
Most of us lose weight the old fashioned way: diet and exercise. Will weight loss help mental function, especially in people who are overweight but not to the point of obesity? What Gunstad hopes to test next is the possible mental benefit from losing weight through diet and exercise rather than surgery. I suspect he will see a benefit, but it could come from exercise as such rather than the weight loss. As I have reported in earlier columns, normal-weight people see a mental improvement from aerobic exercise.
But up to a point, you can just sit in your lounge chair and munch potato chips and still improve your memory—if you are learning from my book, Memory Power 101.
Gunstad, J. et al. (2013). Improved memory function 12 weeks after bariatric surgery. Surgery for Obesity and Related Diseases. 7 (4): 465-472. http://www.soard.org/article/S1550-7289%2810%2900688-X/abstract
Kerwin, D. R. et al. 2010. The cross-sectional relationship between body mass index, waist–hip ratio, and cognitive performance in postmenopausal women enrolled in the Women's Health Initiative. Journal of the American Geriatrics Society. 58 (8): 1427–1432.
Neurologic Complications Associated with Novel Influenza A (H1N1) Virus Infection in Children. Center for Disease Control, July 24 2009