Power Up Your Brain (14 page)

David:
The Greatest Thing

In the spring of 2001, I had the opportunity to present a lecture titled “Stress, Aging, and Neurodegenerative Disorders” at the International Symposium on Functional Medicine in Vancouver, British Columbia. During my presentation, I explained to the physicians and researchers the concepts of stress, the hippocampus, and resetting the hippocampus set point, as described above, using various technical slides and animations to help clarify the relationship between stress and actual functional loss in the brain.

As I was doing so, it became clear to me that most of the research, and even most of my slides, focused on the negative— that stress is bad news. But I wanted to share the good news, too— that positive emotion can heal the brain. So I chose to end the presentation with a slide that showed a photograph of my daughter, perhaps four months old at the time, sleeping peacefully on my wife’s chest. I included an audio clip of Nat King Cole’s song “Nature Boy,” in which he sings about the importance of learning how to love and accept love in return.

THE POSITIVES OF STRESS

But we must remember that stress isn’t all bad. In fact, it is essential for all human progress, just as necessity is the mother of invention. When we are unable to respond with creativity to a challenging situation, it is because we are caught in a neural rut. Our brain’s wiring won’t permit it. When you go to the gym for strength training, you put stress on your muscles, and at the end of the workout, you leave with a toned body and a feeling of accomplishment. Biological stress on a species, such as that caused by a change in food availability due to long-term drought, is resolved through creative coping or adapting. Without the stress of a changing ecosystem, our apelike ancestors would never have left the savannas of Africa for more fertile areas in Asia and Europe; they would not have started walking on two legs instead of four. In those cases, stress was nature’s way of inviting the wisest and most adaptable to survive.

At our present point in human history, with a changing ecosystem and an increased toxic load from poisons in our food and water, our species is once again faced with the challenge of long-term survival. And the enlightenment required of us may be no less daunting than having to learn to walk upright on two legs.

CHAPTER 7

THE GIFT OF
NEUROPLASTICITY

Although we originally developed our amygdala-based fight-or-flight response and our instinctual emotions in order to ensure our survival as a species, allowing the amygdala to control our brain can result, as we’ve seen, in a virtually crippling situation in which our survival is actually compromised.

Luckily, the human brain has the ability to rewire itself and form new connections between neurons so that we do not continue playing over again the tired primitive programs of aggression and fear. Only recently have researchers discovered the potential of the human brain and come to truly appreciate the positive implications of neuroplasticity—the brain’s ability to create new neural networks—for both our individual health as well as for society in general.

We now understand how to harness our brain’s neuroplasticity to enhance certain neural pathways. In essence, we can alter our brain function so that we can more fully access those areas that pave the way for freedom from trauma and destructive emotions; this also allows us to express the genes for health and longevity and even enlightenment.

Neuroscientists have come a long way over the past 25 years. They have replaced the once-accepted paradigm of the brain as a hardwired, fixed, and immutable organ with the belief in neuroplasticity, which celebrates its dynamic ability to learn, adapt, and change.

David:
A Shift in My Understanding

When I was young, I didn’t have the opportunity to spend much time with my father because he maintained a very busy practice in neurosurgery in south Florida. Clearly, he too recognized this shortcoming in our relationship, and one day he came up with a solution: he invited me to the operating room to watch him remove a tumor from the base of a patient’s brain. What a way to spend a Saturday afternoon, especially considering that I was a young teenager at the time! I soon made these visits to the operating room a regular part of my weekends. In retrospect, I believe my dad even made the effort to schedule surgery on Saturdays so I could join him. And, of course, he taught me the proper procedures to maintain a sterile operating room. These procedures would take many hours, so, to pass the time, my father would explain the specific function of that part of the brain upon which we were operating. “This area,” he would say, for example, “is called Broca’s Area, named for Pierre-Paul Broca, a French fellow who, back in 1861, determined that this area controlled speech.” Over time, he described the entire brain in detail, always weaving some bit of historical color into the description.

These experiences at a very impressionable age provided me with a rich and expansive understanding of neuroscience. Later, the idea that specific parts of the brain were dedicated to specific functions was reinforced by the brain research I pursued in college, and it was also one of the key themes in my early publications in the
Journal of Neurosurgery.
Medical school further stressed this connection between particular functions and specific parts of the brain. Hearing of this relationship from so many sources, including my dad, certainly demonstrated that this mentality was pervasive throughout the medical field. And this concept was further reinforced during my years of neurology training. Indeed, it was often said that neurologists learned functional brain anatomy “stroke by stroke.” That is to say, whenever a patient was admitted to the hospital with a stroke in a particular area of the brain, neurologists would note the physical disability that correlated with it and thereby identified which function the damaged brain area served.

This simple mechanical structure/function relationship began to unravel, at least for me, in the late 1980s, when I began to note that some patients would regain considerable function of a particular area of the body following a stroke, even though there had been no observable change in their brain imaging studies. So, while a patient’s MRI continued to show damage in, for example, the part of the brain that controls the left hand, not infrequently the brain would somehow “heal” and functionality of the left hand would return. As more and more neurologists, therapists, and patients observed this unusual phenomenon, neuroscientists began to offer explanations that contradicted the prevailing view of the brain’s abilities.

To this day, I vividly recall what would later become a turning point for me in my understanding of the brain. “Michael,” a 58-year-old graphic designer from North Carolina, came to see me in 1988. He reported that 14 months prior to his visit he suddenly became unable to speak. “I knew what I wanted to say, but I just couldn’t produce the words,” he recounted with perfect fluency. My first thought was that he had experienced a transient ischemic attack (TIA), characterized by a brief decline in blood supply to a particular region of the brain—in this case, an area associated with language expression. But, as he continued, he revealed that his speech had been compromised for at least six months following the attack. There was nothing “transient” about it. And while his recovery had been profound, clearly he wanted to do everything he could to prevent any further brain events.

We reviewed an MRI scan of his brain that had been taken just two months prior to his visit at our clinic, and there, for all to see, was evidence of severe damage and loss of tissue, not only in the area associated with speech, but also in the adjacent areas associated with facial movement and control of the right arm. Nonetheless, his examination revealed no deficits whatsoever. What had happened? Clearly, his brain hadn’t “healed”—at least not physically—because the area of his initial stroke was still damaged, according to the MRI. Yet, his brain had
adapted;
that is, it had begun to use
alternative pathways
to regain functionality of the related affected part of his body.

Of course, the accepted paradigm at the time considered this concept fanciful. Now, however, we know that the brain does have the ability to change and reorganize itself in regard to the functions it performs. This process is called neuroplasticity, and it is a gift on par with neurogenesis, the brain’s ability to generate new cells throughout our lifetimes.

CHANGING OUR NEURAL NETWORKS

Through neuroplasticity the brain is able to rewire neural pathways, and even establish new neural superhighways. When a person suffers a stroke and loses function in the right hand, for example, the brain can create new pathways that may allow the left hand to perform some of the functions previously done only by the right.

Neural networks are created by focused, engaged stimulation. It takes more than simple repetition to create neural networks. Professional athletes have long known that practice does not necessarily make perfect, because bad practice simply reinforces a less than ideal pathway in the brain. Likewise, repeating a prayer over and over without positive focused intention makes enlightenment less likely. If you want to experiment, try brushing your teeth or holding your fork with your nondominant hand and notice how much concentration is required to perform this simple task. Likewise, the practice of joy, kindness, and forgiveness take focused attention to develop, but the more you exercise them, the more easily and naturally they come.

Michael Merzenich, professor emeritus at the University of California, San Francisco, performed a series of experiments in the mid-1990s that demonstrate the need for focused attention in order to learn new skills and behaviors. In one experiment, he applied a tapping stimulus to the fingers of two groups of monkeys. When the rhythm of the tapping occasionally changed, monkeys in one group received a reward of juice for responding to the change. The other group of monkeys was not rewarded for responding. After six weeks, Merzenich examined the monkeys’ brains. The animals who had paid close attention to the stimulus, waiting for the change in rhythm so they could collect their reward, exhibited profound differences in the areas of the brain associated with processing tactile stimuli. No such changes were seen in the brains of the monkeys who were not rewarded for paying attention to the stimulus even though the stimulus, the tapping on their fingers, was exactly the same for both groups.
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