THE BUTTERFLY EFFECTMeteorologist and mathematician Edward Lorenz wanted to know how to model weather patterns. Instead, he discovered two great truths: First, even the tiniest of events can generate enormous consequences; and second, it’s impossible to forecast weather very far into the future.
At the Massachusetts Institute of Technology in 1961, Lorenz created a rudimentary computer program that simulated basic weather. The computer ran 12 equations to crunch weather data, such as air pressure, temperature, wind, and so on, that ran to six digits after the decimal point. One day, Lorenz wanted to run a longer-than-usual test, so he restarted a previous weather computation from the middle instead of the beginning. To make a compact printout, he decided to enter only the first three digits after the decimal point—representing his measurements to the thousandth part instead of the millionth. He figured that because he had made only the most minuscule changes to his input, the weather patterns would look the same.
Surprise. The new weather pattern veered dramatically away from the original. That fourth decimal place mattered. A lot.
Lorenz had discovered the roots of chaos theory. Science cannot measure everything, in infinite detail, that might affect a complex physical system. This means it is impossible to perfectly predict the system’s performance in the future. Long-term meteorological forecasts fail because humans can never measure every variable, such as air temperature, down to the individual molecules of atmospheric gases. Nor can they predict when a particular unmeasured quality plays a crucial role in the system’s performance.
THE BUTTERFLY EFFECTLorenz’s discovery has become known as the butterfly effect, after the title of his famous 1972 paper (“Does the Flap of a Butterfly’s Wings in Brazil Set Off a Tornado in Texas?”). Most of the time, a butterfly flapping its wings doesn’t alter weather patterns. But it can! Under the right conditions, the chain of events sparked by a butterfly fluttering or not fluttering its wings can lead to a storm.
Although weather is extremely complex, the human brain is ever so much more so. As a complex physical system, it too is subject to chaos theory. The tiniest thing can become its tipping point, leading to a significant, concrete change.
It could tip for bad or good. Missing the bus to work by ten seconds might aggravate preexisting emotions enough for something truly bad to happen, such as causing you to get fired. Or, finding an Indian head penny in the dirt could lead to coin collecting as a new hobby, or drive away a dark mood and lead to a significant stretch of happiness. The decision to go for a walk around the block tomorrow morning before work, eat fresh fruit for breakfast, or do a crossword puzzle while waiting to see the dentist could signal the start of a new lifestyle that strengthens both body and brain.
The difference between the brain’s bad and good tipping points is largely a matter of choice. Humans don’t have the ability to stop bad things from happening. They can, however, use free will—the power to choose, embedded in the uniquely human prefrontal cortex—to opt to take steps to improve brain health. Chaos theory says the smallest step can lead to enormous alterations. You might do a brain exercise or two in this book and find yourself liking how you feel afterward. That may lead you to check out other mental or physical routines, within these pages or without. Before you know it, you’ve made a noticeable change in your mental circuitry. Your brain’s plasticity ensures it will change as it makes new connections among your billions of neurons and even grows new brain cells in the hippocampus. Your free will makes you the engineer of those changes in your brain.
GET PHYSICALYour brain and body are connected by nerve bundles that move muscles and keep organs functioning. Nerves also provide sensory stimuli from your body for your brain to process. It should be no surprise, then, that a healthy brain begins with a healthy body. Recognition of the mental–physical relationship dates at least to ancient Rome, which gave us the Latin phrase Mens sana in corpore sano (“A sound mind in a healthy body”).
BRAIN INSIGHT
A Walk in the Park
Sometimes, helping your brain may be as simple as a walk in the park
Marc Berman, a postdoctoral fellow at Toronto’s Rotman Research Institute, found that walking for an hour improved cognitive function and mood among adults diagnosed with clinical depression. Berman recruited 20 clinically depressed subjects in and around Ann Arbor, Michigan, and assigned them to two groups. The first walked for an hour in a peaceful woodland setting and the second for an hour in a noisy urban setting. A week later, the two groups switched venues and repeated the experiment.
Berman was skeptical: People with depression often seize on dark thoughts, and a solitary walk might give them time to focus on painful times in their lives.
Surprisingly, the 2012 study found that walkers in both settings experienced a boosted mood. Furthermore, those in the natural setting improved attention and working memory by 16 percent compared with those in the urban setting.
The study built upon a 2008 experiment that demonstrated that people without any diagnosis of illness enjoyed increased memory and attention after a woodsy walk.
Berman believes a peaceful, natural setting eliminates distractions that bombard the brain’s memory and attention circuits, allowing the brain to relax and restore itself.
Many brain health programs begin by focusing on the body’s physical health. The brain’s around-the-clock work schedule consumes a quarter of all the blood the heart circulates. The stronger the pumping heart, the more efficient the functioning of the brain. Having a healthy heart requires a proper diet, low in fat and high in fiber and antioxidants, as well as a regimen of regular exercise and abstention from dangerous toxins such as those in tobacco and illegal drugs.
Any kind of exercise is better than none. Walking, swimming, dancing, biking … whatever elevates your pulse and gets you sweating improves the function of your heart and lungs, sending life-giving oxygen to your neurons. Exercise has been found to reduce the risk of heart attack, diabetes, and colon cancer, and also beneficially affects blood pressure and mood. But exercise also physically changes the brain. Aside from boosting the amount of oxygen red blood cells carry to the neurons, exercise increases the density and number of blood vessels in the motor cortex and cerebellum, which control conscious and unconscious movement. True exercise is the key—you can’t boost the amount of oxygen to your brain simply by speeding your breathing patterns. Deliberately trying to hyperventilate, by taking fast and shallow breaths, actually decreases oxygen levels in the brain. Cerebral hypoxia, or low levels of brain oxygen, can cause fainting.
In addition to heart and artery disease and lack of exercise, factors that limit the flow of blood to the brain include:
Nicotine. Smoking cuts the flow of blood to every organ, and the brain is no exception.
Dehydration. No surprise here: The brain is 80 percent water. When starved for water, it staggers to perform physical functions and struggles to focus attention.
Caffeine. Not only does it directly reduce blood flow, but it also can disrupt sleep and cause dehydration. On the other hand, some evidence suggests benefits to the brain from the daily stimulus of a measured amount of caffeine in coffee or tea. For example, caffeine improves attention, which is essential to learning and memory.
Lack of sleep. Studies have shown that people who sleep less than six hours per night have decreased blood flow to the brain. As anyone would know when getting out of bed after a fitful night of tossing and turning, a poor night’s sleep also impairs memory, mood, and overall cognitive function.
Drug and alcohol abuse. Drugs and alcohol have a toxic effect on vessels that carry blood and other bodily fluids. Like caffeine, however, red wine may have some benefits for the brain—not because of its alcohol content, but rather because of an ingredient called resveratrol that protects blood vessels.
Other toxins. Many environmental poisons damage blood vessels.
Diabetes. The disease causes blood vessels to grow brittle and interferes with proper healing of damaged tissue. It also increases risk of stroke.
Stress. When the body reacts to potential danger, whether real or imagined, the endocrine glands prepare it for “fight or flight”—to supercharge it for combat against an enemy or predator, or to prepare it to run away. The flood of the stress hormone adrenaline shunts blood to the muscles at the expense of other regions.
A small amount of stress can spark the brain to higher achievement, but stress that’s too intense or chronic can damage the brain through changes in blood flow and pressure. Spikes in pressure caused by adrenaline can leave blood vessels vulnerable to breaking, which can be catastrophic in the brain. In addition to adrenaline, the stress hormone cortisol appears to impair memory. Studies of elderly adults demonstrated that those with high cortisol levels from long-term exposure to stress did worse on memory tests than similar adults with low levels of cortisol. The high-cortisol group also had smaller hippocampi, the brain region most closely associated with integration of memories. Children who experience prolonged exposure to high-stress environments also have trouble concentrating and learning.
VITALITYBesides improving physical health, exercise boosts self-esteem. That’s a part of vitality, another major component of brain health. Vitality includes feeling that your life has meaning, and that you enjoy living it. It means handling the storms and sunshine of life, mentally holding both positives and negatives in balance. A healthy social life is crucial to vitality, whether found in a circle of friends, co-workers, relatives, a church, or a community group.
Moods arise from chemical reactions in the brain. They also cause the brain to release chemicals that affect mood. It can be a vicious cycle. Negative mental states such as depression cause the brain to alter its balance of neurotransmitters in a way that supports a negative mood and interferes with brain functions. The mood-altered brain then mechanically releases even more chemicals linked to depression. Unchecked, this cycle can lead to isolation from a social circle (which usually enhances depression), and correlates with higher risk of dementia. On the other hand, happiness releases brain chemicals that benefit both brain and body even after the moment of joy passes. Laughter truly is a form of medicine.
Introspective techniques such as meditation can improve vitality and increase brain health. But you don’t have to be a yogi to boost your inner peace. Because brain and body are so closely connected, you are, in part, what you eat, reinforcing the body’s mental–physical relationship. Take fish, for example. A diet rich in fish and shellfish has been shown in multiple studies to keep the mind sharp and lower the risk of certain brain disorders. Residents of Iceland, who eat about five times as much seafood as Americans and Canadians, rarely have depression. Fish oil and, in particular, omega-3 fatty acids have been linked not only to brighter mood but also more efficient transmission of electrochemical signals between the synapses. Eating more fish may even raise the brain’s shields to fight the onset of dementia.
WORK IT OUTAlong with physical health and vitality, a healthy brain requires something known as cognitive fitness. It’s a measurement of the brain’s functioning in four arenas: perception, attention, thinking, and language. All respond to the stimuli of new, complex activities by sprouting tangled thickets of axon-dendrite connections. The greater the complexity and novelty, the more the brain responds by making its internal connections even more complex.
Enhanced brain fitness has value in its own right. It feels satisfying at any age when you demonstrate mental agility and speed, as when you answer the questions while watching a game show on television or solve clever puzzles in the Sunday newspaper. But there’s another, long-term benefit to engaging in brain-challenging games and activities: They raise your chances of maintaining your cognitive skills into old age. It appears that having a “brain reserve” of extra neural connections may provide a buffer against mental and physical decline with age.
Some loss is inevitable. The average human brain weighs about 1,400 grams, or roughly three pounds, at age 30. By age 90, the brain has lost 90 to 100 grams. The drop could be the result of neural death, loss of axon–dendrite connections that shrink neurons’ weight, or both. Still, a popular theory posits that complexly wired brains have greater ability to hold on to their cognitive skills with advancing age. If something affects a number or percentage of neurons, it will have more impact on brains that are less fit and that have fewer neural connections. Richly wired brains still suffer neural losses, but they’ll cope by shifting cognitive tasks to the web of neurons that remains.
A cognitive reserve acts like a savings account tapped on a rainy day to pay unexpected bills, which would break the bank of someone without the extra money. To use a computer example, imagine two brains as two internal hard drives. One brain, which has undergone fitness training, has added the equivalent of a supplementary memory, such as a flash drive or CD-ROM reader and stack of computer disks. When the enhanced computer loses its supplementary memory, its hard drive still functions. The loss may not even be noticeable. Such appeared to be the case with a study of nuns in Mankato, Minnesota, whose shared lifestyle made them ideal subjects. The nuns who had developed neurally enhanced brains through a lifetime of challenges appeared to keep their cognitive skills longer than those whose brains had less cognitive fitness. Sometimes, an autopsied nun’s brain revealed the physical signs of Alzheimer’s disease, even though the nun showed no evidence of Alzheimer’s while alive.
Just as the body grows stronger when its muscles are challenged, the brain grows more fit when taxed by new kinds of learning. Adding a new language, musical instrument, or cooking skill are examples of creative categories of brain challenges. Smaller versions of those challenges work, too, thanks to chaos theory and neural plasticity. You don’t have to learn Italian to enhance your brain fitness, for example, but if you’re an opera buff, you might try learning the words—and meaning—of the soaring “Nessun dorma” (“None shall sleep!”) from Giacomo Puccini’s Turandot. Not an opera fan? If you’ve played the same six chords on the guitar since you were 15, you don’t have to take up the clarinet. Instead, try mastering the melody of George Harrison’s “Here Comes the Sun” on your six-string, or any other song that stretches your skills beyond your old limits. Always enjoyed basic Mexican cooking? Try making a mole sauce next time.
The glory of a good brain workout is that you don’t have to pay for a gym membership or set aside a regular part of your daily schedule to take part. Many of the brain fitness activities explained in these pages can be done in just a few minutes, virtually anywhere and at any time.
If you want to go beyond the suggestions in this book, many games are available online, and software packages designed specifically to build skills, such as short-term memory, or build a reserve through intellectual engagement, such as learning a new instrument or traveling, are offered for purchase by a variety of manufacturers.
BRAIN INSIGHT
The Homer Simpson Gene
Could evolution have selected for a gene that makes us stupider?
Normally, when a gene is disabled or mutated, bad things result. However, knocking out a mouse gene known as RGS14 actually increases the mouse’s ability to learn and remember information. A protein produced by the gene is believed to play a crucial role in the creation of memories, but strangely, when the gene is deleted in genetically altered mice, they get better at remembering and recognizing objects, easily recalling locations to help them speed more quickly through water mazes.
Pharmacologist John Hepler and colleagues at Emory University are so confident that RGS14, also found in humans, lowers brain performance that they have nicknamed it the “Homer Simpson gene,” in honor of the cognitively challenged cartoon character. Mice without the gene created long-term, strong connections among neurons in the CA2 region of the hippocampus.
This raises what Hepler calls a big question: Why would evolution select for a gene that makes the brain less smart?
“I believe that we are not really seeing the full picture,” he said. “RGS14 may be a key control gene in a part of the brain that, when missing or disabled, knocks brain signals important for learning and memory out of balance.”
Further in the future are potential studies of the gene’s impact on performance of the human brain.