How Health & Environment Change Your Brain
In our last newsletter, we explored those programs that run automatically in your brain and influence the way you see the world. In this issue, we flip our perspective 180 degrees and view those outside events that physically change your brain's internal structure.
When you think about it, it's actually pretty amazing that seemingly unrelated external events or circumstances can literally alter your brain for good or ill -- sometimes permanently, unless somehow it's deliberately changed back. What external events am I talking about? Well, there are actually a large number, but for the purposes of our discussion, we will limit ourselves to four: obesity, where you live, music, and meditation and/or deep prayer. That's right! As we are about to explore, your weight determines your ability to perceive pleasure, which leads to more weight. Where you live affects the function of your amygdala, which affects your ability to deal with stress. Or to put it another way, the more stressful your living environment, the less capable your amygdala is of dealing with stress, and once it's changed, simply moving to a less stressful environment will not change it back. Listening to and playing music literally improves your language skills and ramps up your intelligence. And meditation and deep prayer can repair much of the damage caused by other outward circumstances. As I mentioned earlier, these are not the only things that can change our brains, but they are significant and they provide an effective representation of the entire category. With that in mind, let's take a look at them in some detail.
Ultimately, obesity is a matter of calories in VS calories out. The more you eat, the more you have to burn to prevent weight from piling on. Nowadays, we not only eat more than ever before, but we also burn less. It sounds simple, but several factors complicate the equation.
- First, the more muscle you have the more calories you burn even at rest. A pound of muscle burns up to nine times the calories of a pound of fat. The reason for this is that muscle is active tissue. In other words, it requires a lot of energy just to maintain itself. In fact, every pound of new muscle you add to your body will burn about 60 calories per day. Adding just 10 pounds of muscle to your body, will burn off 62 pounds of fat over the next year -- even while you are sleeping! And it will continue to do so the next year…and the next.
- Stress and/or lack of sleep increases cortisol levels, which stimulates the production of insulin and raises blood sugar levels. As a reaction to this flood of insulin and sugar produced by the body, we begin to crave even more of it. Elevated levels of cortisol enhance our desire for sugar and carbohydrate-rich food, otherwise known as comfort food. And not only can cortisol cause you to eat more, but it also affects the way your body distributes its fat stores. Research indicates that stress and high cortisol levels promote weight gain around the midsection rather than in the lower half of the body. This type of core fat is the most dangerous type of weight gain as it is a major risk factor for heart attacks, strokes, and diabetes.
- For similar reasons, certain foods, such as high fructose corn syrup (HFCS) create cravings for more of the same. The more HFCS you eat, the more you feel compelled to eat -- thus piling on the weight.
And now recent studies suggest a much more insidious complication. It seems that the more you weigh, the more your brain is fundamentally altered so as to compel you to eat ever more and become ever more obese.1 If true, it means, yet again, that although everyone is faced with the same "calories in VS calories out" equation, it is nevertheless fundamentally harder for overweight people to regulate their weight than for fit people.
The key to it all is insulin, which circulates in blood in proportion to your fat mass.
For many years, it has been known that insulin acts as a metabolic signal transmitter in the hypothalamus, providing information to the brain about the body's state of satiety.2 Insulin, which can pass through the blood-brain barrier, binds to nerve cells in the hypothalamus and gives the signal for satiety. The higher the levels of insulin in the blood, the greater the sense of satiety. According to this feedback system, the more you weigh, the higher the levels of circulating insulin will be in your body. Theoretically, then, the more you weigh, the less your appetite should be. But as we know, the exact opposite seems to be true.
The new study, however, found that insulin also acts as a signaling agent in the midbrain, where it acts on dopamine-producing cells. In this feedback system, insulin rewards you for eating more by creating a sense of pleasure in the brain and body. What makes this study so important is that the researchers determined that this dopaminergic mechanism is superior to the satiety mechanism in the hypothalamus. In other words, it overrides it. The reason it is so powerful is that dopamine is known as the "happy hormone" and plays a major role in stimulating addictive behavior. In effect, this system turns overeating into an addiction -- and being overweight is your pusher.
The bottom line is that researchers seem to have proven that insulin plays a direct role as a transmitter in the brain's reward system. As the scientists admit, there are questions still to be answered. For example, why does the brain have two regulatory systems for satiety, and how do they work together? But what does seem pretty clear is that the signals from the midbrain override the hypothalamic satiety system and reward you for eating more and for being overweight despite any signals you may receive that say you've eaten enough. Quite simply, the more you eat and the more overweight you are, the more insulin you produce, and thus the stronger the dopamine reward system in your midbrain. The more you weigh, the harder it is to avoid eating to excess, and so more and more weight piles on, which makes it ever harder to avoid ever more overeating.
Urban living VS country living
Okay, I realize that there are some who might argue that the changes to the obesity mechanisms described above don't qualify as fundamental. If you simply lose the weight, the mechanism shuts off. I would tend to disagree, but since this newsletter is not about obesity, but about the ability of outward circumstances to effect fundamental changes in the brain, let's take a look at another study that concerns the impact of where you live on your brain.
As with the obesity study, the latest study does not exist in a vacuum. Researchers have known for some time that country life and city life affect our mental states. For example, a 2009 study published in Acta Psychiatrica Scandinavica showed a 21% increased risk of anxiety disorders and a 39% increased risk of mood disorders for people living in urban environments.3 In addition, a 2005 study published in the Oxford Journal's Schizophrenia Bulletin found that the incidence of schizophrenia is twice as high for those born and raised in a city environment.4 In addition, it has been shown that the larger the city, the greater the risk of psychiatric illness. And in fact, this is hardly a mystery. We know that the pressures of city life are more stressful then the idylls of country life -- a motif exploited in films such as Doc Hollywood and its more recent cartoon clone, Cars. (You do know they are the same movie, right?)
But the most recent study has taken our understanding of how city brains and country brains differ to a whole new level. In this study, the researchers used brain scans to determine that two regions in the brain, both involved in the regulation of emotion and anxiety, become overactive in city-dwellers -- permanently.5 Or to put it another way, city life causes fundamental changes in the stress center of the brain. Specifically, the study showed that the amygdalas (the area of the brain involved in regulating anxiety, fear, worry, and other stress related emotions) of participants who currently live in cities were over-active during stressful situations. The other region of the brain that became overactive in city dwellers was the perigenual anterior cingulate cortex (PACC), which is important in controlling emotion and dealing with environmental adversity.
This was determined through the use of functional MRI (magnetic resonance imaging) brain scans on students who were asked to solve mathematical problems while being stressed through forced time constraints and derogatory harassment by the researchers. Based on where the participants were raised and where they currently lived, the researchers found that the students who currently lived in a major city showed significantly higher activity in their amygdalas and cingulated cortexes than the country dwellers. Considering that by 2050, it is predicted that almost 70% of people will be living in urban areas, this is significant.
The researchers speculated that stress is not only the most likely cause of these structural abnormalities in the first place, but that these abnormalities then express themselves as increased stress in the individual -- and that the net result is an increased risk of mental illness. To quote from the researchers, city dwellers tend to be "wealthier and receive improved sanitation, nutrition, contraception and healthcare," but in exchange, city dwellers are more likely to see an "increased risk for chronic disorders, a more demanding and stressful social environment, and greater social disparities." One other observation that the researchers made is, "There's prior evidence that if someone invades your personal space, comes too close to you, it's exactly that amygdala-cingulate circuit that gets [switched on] so it could be something as simple as density [of a population living in a given environment that triggers the changes in the brain]."
The key point, though, in terms of our discussion, is that this observed increased vulnerability to stress found in city dwellers is permanent. Moving to the country after being raised in the city doesn't "repair" the brain. The increased sensitivity to stress created in the city continues unabated across the entire lifespan even if you retire to the country. On the other hand, that observation of permanence is based on the relatively passive action of merely moving to another environment. Can the brain's stress response be repaired if you take more proactive actions? In fact, the answer is yes, and we will discuss that a bit later.
Sherlock Holmes didn't play the violin for nothing
Not all changes to the brain affected by outward circumstances are negative. The right stimuli can actually improve brain function. Let's take a look at a couple of positive stimuli.
The benefits of music on the brain are some of the most studied in the field of psychological research. For example, in a blog earlier this year, we examined a study out of McGill University in Montreal, Canada that demonstrated that music, an abstract stimulus, can arouse feelings of euphoria and craving, similar to tangible rewards that involve the striatal dopaminergic system.6 In effect, music affects the brain chemistry the same way that other activities associated with satisfaction, such as having sex, eating, and being overweight do; and it elicits the exact same response. When we listen to a favorite piece of music -- whether it is a symphony, jazz, or even a gangsta rap song -- the brain releases dopamine, which provides the sensation of pleasure. And yes, this is virtually the same midbrain dopaminergic response produced by excess insulin as cited earlier in our discussion of obesity.
Using PET scans, the researchers discovered that neurons were pumping out more dopamine when they were hearing the pieces they favor than other more neutral songs. The scans also showed that the dopamine was traveling through circuits to the striatum (an area of the brain associated with executive decisions and rewards) when the subjects were anticipating highlights of the music and to the mesolimbic pathway (an area of the brain associated with memory and rewards) when the climax of the song was playing. MRI scans were used as well to pinpoint exactly when during the music and where in the brain these surges in dopamine delivery occurred.
The same research team had conducted an earlier study that demonstrated the ability of music to bring about intense emotional feelings, such as changes in temperature, heart rate, pulse, and breathing. They used PET scans to obtain evidence that blood flow increases to the regions of the brain connected with dopamine release.
Again, as with the dopamine kick provided by obesity, this might be considered a non-fundamental change, since it's easily reversed or prevented by simply not listening to your favorite music. But this is only one study. There are others.
In 2008, we posted a blog about a study published in PLoS ONE that revealed that after studying a musical instrument for at least three years, elementary school kids not only trounced their peers in tests of auditory discrimination and finger dexterity, as might be expected, but they also outperformed them in both verbal ability and non-verbal reasoning, as measured by IQ tests.7 Even more striking was the fact that the longer and more consistently the kids had been playing their instruments, the higher their scores.
And this is supported by earlier studies. For example, a 2003 study found that cardiac rehabilitation patients who listened to music while exercising increased their verbal fluency scores.8 A 2002 study found that a professional musician's auditory cortex contains 130 percent more gray matter than that of non-musicians, suggesting that the regular music practice required by a professional musician, increases the growth of brain matter. And musicians who began study early in life appear to have an especially enhanced neural bridge between the brain's hemispheres.9 Then there's the 2006 research out of Canada that found that the brain develops differently in children who receive even a year of musical training, and that those children have superior memory capacity and cognitive ability.10 And a 2007 study found that adults who had completed at least three years of musical training before the age of 12 had far more linguistic capacity when compared to non-musicians. The researchers in that case found that the musically trained subjects had changes in their brain stems -- the part of the brain that controls breathing and heartbeat.11 These studies and others add hard evidence to the argument that musical study actually changes the brain.
The bottom line is that listening to and playing music permanently enhance the brain in multiple ways.
Meditation, deep prayer, and focused chanting
We all understand that if we want to be good tennis players, we need to practice for hours on end for many years. If we want to be a good doctor, we have to go to school for many years. If we want to be good at anything, we have to pay our dues in terms of long hours of practice. And yet for some reason, most people assume that somehow we should just be born with the ability to maximize our minds. If only! As it says in the Bhagavad Gita, "The mind is restless, impetuous, self-willed, hard to train: to master the mind seems as difficult as to master the mighty winds."
And it is in this particular discipline that religion has taken the lead. Yes, much of religion is rife with dogma, bigotry, and narrow mindedness, not to mention its role as a catalyzing agent in many wars. But that said, probably no activity in the history of humankind has done more to develop the disciplines required to consciously change the structure of the brain and harness the power of the mind than religion. Rituals, austerities, the use of music (as noted above), and spiritual drills, etc. have all been used by the world's religions to learn to control the mind and maximize its potential. But of all the disciplines developed by the world's great religions, meditation, deep prayer, and focused chanting are probably preeminent in this regard. I am not talking about casual prayer such as asking for a parking space when pulling into the mall parking lot. I am talking about formalized meditation, disciplined deep prayer, and prolonged focused chanting as taught by most of the world's religions. These are brain changers. These are health changers.
And finally, earlier this year, scientific research verified exactly how these disciplines actually work. According to the study, which appeared in the January 30th issue of Psychiatry Research: Neurology, focused meditation appears to make measurable changes in brain regions associated with memory, sense of self, empathy, and stress.12 This is, in fact, the first study ever that proved that meditation produces changes over time in the brain's grey matter. (Note: meditation, deep prayer, and focused chanting essentially accomplish the same thing.)
Although previous studies had been able to associate changes in brain structure as the result of meditation, such as thickening of the cerebral cortex in areas associated with attention and emotional integration, those studies had not been able to prove that the observed differences were actually caused by meditation. This year's study, though, finally proved the long suspected cause and effect relationship. For the current study, MR Images taken before and after an eight-week program of approximately 30-minutes a day of mindfulness meditation were compared. Before and after sets of MRI scans were also taken of a control group of non-meditators at the same time.
Analysis of the scans, which focused on areas where meditation-associated differences were seen in earlier studies, found increased grey-matter density in the hippocampus, known to be important for learning and memory, and in structures associated with self-awareness, compassion, and introspection. Participant-reported reductions in stress also were correlated with decreased grey-matter density in the amygdala. Remember earlier when I said that there might be more to the story concerning researchers' declaration that changes to the amygdala as a result of city living were permanent? Well, it would appear that, contrary to what the researchers said, it's absolutely within your power to change your brain back to a lower stress mode…if you work at it. And as you probably suspected, none of these changes were seen in the control group, indicating that the beneficial brain changes had not resulted merely from the passage of time.
Britta Hölzel, the study's lead author, put it beautifully when she said, "It is fascinating to see the brain's plasticity and that, by practicing meditation, we can play an active role in changing the brain and can increase our well-being and quality of life."
So where does that leave us? In our last newsletter, we learned about those programs which are hard-wired into our brains and that put us into stimulus/response mode. Given a particular stimulus, such as a challenge to one of our core beliefs, our brains, without any conscious thought on our part, start running preprogrammed responses -- such as an irrational defense of those beliefs, no matter how compelling the arguments against them. The only way to stop those automatic programs is to be completely aware of them and to stop them from running the moment they begin to run…if appropriate.
On the other hand, in this newsletter, we learned that stimuli from outside our brains can actually make physical changes in our brains that also automate our responses to and feelings about certain things and situations such as food and stress.
But more importantly, we learned that we have the ability to override each and every one of these things. With conscious effort, we can stop automated programs from running…when those programs are counterproductive. By taking certain actions, such as listening to music or practicing meditation and/or deep prayer, we can actually "repair" areas of our brains that have been previously altered to our detriment.
This is hugely liberating and life-altering if you choose to act on it.
I have always said that the most important and least understood chapter in Lessons from the Miracle Doctors is the one entitled: The Thought that Kills. Do yourself a favor and read it now. If you don't already have the book, you can download it for free at jonbarron.org.
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