Many of you are aware that my brother Steve had a stroke in October. I’m glad to report that he’s recovered almost completely. His voice is still a little flat, but it’s greatly improved from just a month ago. And he’s gotten serious about taking care of himself. When I talked to him on Christmas Day, he sounded almost like his old self—except for the fact that he said he’d just gotten back from a four and a half mile walk!

Steve was lucky. The stroke occurred while he was at home. His wife, Lavinia, knew what was happening and got him to the hospital within that golden three hour window when the clot busting drug TPA can be administered.

Every year some 750,000 Americans suffer a stroke; it is the country’s leading cause of disability, and it can occur at any age. Getting medical help soon enough can make all the difference but many stroke victims don’t because they and the people around them don’t even realize they are having a stroke. There are three simple tests to tell whether someone is having a stroke. Does anyone know what they are? Ask the person to smile; ask them to talk—to speak a simple sentence; ask them to raise both arms above their head. If the person has difficulty with any of these tasks, you should call 911 immediately. These three tests are easy to remember because the tasks—smile, talk, raise - begin with the first three letters of stroke. STR—smile, talk, raise both arms. Okay—that’s my public service announcement for the day.

You might be wondering how we got from the dream of world peace to talking about stroke. Well, there is a connection—and I hope that by the end of this sermon or at least by the end of the second sermon in this series two weeks from today—that you’ll see that the connection is not that tenuous. The connection has to do with neuroplasticity.

What is neuroplasticity? Most simply, it means the ability of the brain to change itself. Neuro stands for neuron, the nerve cells in our brains, and plasticity means the ability to be altered. When something is plastic it is malleable, modifiable. So neuroplasticity refers to the ability of the brain to change and not just to change in the ways we would normally think of—such as the ways in which a child’s brain changes as the child develops or the way in which the adult brain changes when we form new memories or learn something new. No, neuroplasticity refers to wholesale changes in the job functions of areas of the brain. In the last few years research in several different arenas has come together to radically alter the way scientists view the human brain so that we now know that the brain can and does change over the course of a lifetime; that it can change fundamentally in both structure and function; and, that it can even repair what we previously thought was irreparable damage, such as that suffered by stroke victims.

Up until just recently the conventional wisdom was that the adult brain is fixed in two respects—that no new neurons are ever born in it and the functions of the structures that comprise it are immutable, so that if genes and development dictated that a certain cluster of neurons processes signals from the eye and another cluster makes the fingers of the right hand move, then that’s the way it was going to be, forever and ever, amen. The only changes scientists thought possible in the adult brain were those involved in learning and memory which occur through the growth of new synapses, the places where neurons connect, or through the strengthening of existing synapses. But wholesale changes, such as expanding a region in charge of a particular mental function, or altering the wiring that connects one region to another, were deemed impossible.

Some of you have seen those diagrams in science textbooks that authoritatively lay out the structure of the brain. There’s the visual cortex in the back which is wired for sight; the auditory cortex which receives input from the ears; the somatosensory cortex, that strip that curves along the top of the brain, which processes tactile sensations, and which can be mapped to its corresponding body parts; and just in front of it, the motor cortex which accords a precise amount of neural real estate to each muscle, and so forth. Now, by and large, this description of the apportionment of neural real estate—called localization—roughly holds true for most people. And because it roughly holds true, it had taken on the status of dogma. It was considered fact that by the time a human being had reached adulthood, every bit of neural real estate had a fixed function that was “hardwired”—like the circuits in your computer’s hard drive. These functions simply couldn’t be changed. The idea, for example, that the auditory cortex might, because of varying input from the outside world, begin to process sight was unimaginable.

But that’s exactly the sort of thing that pioneering neuro-scientists have proved is possible. Through discovery after discovery, they have learned that the brain retains stunning powers of neuroplasticity into ripe old age. The brain can be rewired; it can grow new neurons; it can reactivate long dormant circuits and grow new ones. It can reassign areas of the brain to assume a totally new task and it can repair damaged areas. The blind can see; the deaf can hear; and the stroke victim can speak and move their paralyzed limb again. That the brain retains powers of neuroplasticity is an amazing discovery; but equally startling is how it does so. The actions we take can literally expand or contract different regions of the brain; rev up relatively quiet circuits; or, damp down overactive ones. You see, the brain devotes more cortical space to functions the owner uses more frequently and shrinks the space devoted to activities rarely performed—hence the catch phrase—use it or lose it. For example, a violinist’s motor cortex has more space devoted to the digits of the fingering hand than that of a non-musician, something easily discernible through new imaging techniques, such as the functional MRI. In response to the actions and experiences of its owner, a brain forges stronger connections in some circuits and weakens the connections of others. Most of this allocation of resources happens because of what we do or because of input from the outside world, but there’s also research that suggests that brain changes can be generated by pure mental activity—in other words, that we can change our brains simply by our thoughts.

Now I know that probably sounds like some new age spiritual mumbo jumbo to some of you—and, I’ll admit, it did to me, too, at first. But in order to understand what that means—that we can change our brains simply by thinking—we need to understand more about the basic discoveries underlying neuroplasticity.

As I said, the more you do something, the more cortical space becomes devoted to it, as in the case of a violinist’s fingering hand. And this reapportionment of cortical space happens without apparently damaging other motor control. This kind of plasticity has been documented over and over again. In a typical experiment, for example, monkeys were taught to extract banana flavored pellets from tiny cups only large enough for one finger. It was quite a feat which took them some time to learn—it involved tapping the pellet until it stuck to the finger long enough to elevate it out of the cup and get another finger around it. The monkey’s motor cortices were mapped before and after the training. After the monkeys mastered this trick, scientists found that the area that moved the fingers, wrist and forearm—which were getting quite a workout—had doubled, taking over motor cortex that had previously controlled other parts of the body. Other experiments have shown that if cortical space is not being used, adjacent areas tend to move in, like squatters. If, for example, part of the somatosensory cortex is not receiving input from the external world, as when nerves are severed or limbs amputated, the brain space devoted to the sense of touch for those areas is appropriated for sensation by adjacent parts of the body. Now these discoveries may not be so startling in and of themselves—that some of the motor or sensory cortex responsible for one body part can be devoted instead to another near-by body part. But what is truly amazing is that researchers have built on discoveries like these to uncover what they now know is the poly-sensory nature of sensory processing areas. Let me explain.

In the past, it was thought that if a person was, say, born blind, that their visual cortex was like a neuronal black hole—that because it wasn’t receiving any sensory information from the outside world that nothing was going on in that part of the brain. But it appears that the brain doesn’t like space going to waste. Technological advances in monitoring brain activity have revealed that the visual cortex of the blind is not dead space. It’s busy processing other kinds of sensory input, such as auditory or tactile sensations. Moreover, the brain’s sensory areas are all connected to each other and, if need be, can substitute for one another and learn to process information that would normally be processed in a different area. In one of the most amazing neuroplasticity experiments, a neuro-scientist rewired the brains of young ferrets. He surgically redirected the optic nerves from a ferret’s visual to its auditory cortex and discovered that the ferret still learned to see. He proved that when the ferret was seeing, the neurons in its auditory cortex were firing and doing the visual processing. The auditory cortex had reorganized itself so that it had the structure of the visual cortex. Admittedly, the ferrets didn’t have 20/20 vision. They had 20/60 vision, but that’s no worse than many people who wear glasses. Pioneering scientists have been able to exploit this poly-sensory nature of the brain to teach human adults who were blind from birth to actually see—to form visual images—by processing other kinds of sensory sensations. Similar experiments have restored the sense of touch to victims of leprosy, whose illness destroys peripheral nerves so they lose sensation in their hands; restored a sense of balance to people whose vestibular regions have been destroyed; and, there is research which may restore orgasmic response in spinal cord injury victims. (Just trying to keep your interest here, folks.) And neuroplasticity is not limited to merely reorganizing the brain so that one sensory region handles a different sense. Research has shown that in people blind from birth, the visual cortex has been appropriated by the brain to perform the sophisticated cognitive function of language processing!

Neuro-scientists have not yet discerned all that is involved in neuroplasticity. But they think that at least part of the explanation lies in unmasking little used neural circuits. One scientist describes its by analogy this way: “If you’re driving from here to Milwaukee and the main bridge goes out, at first you’re paralyzed. But then you take old secondary roads through the (countryside). As you use these roads more; you find shorter paths to use to get where you want to go, and you start to get there faster. These “secondary” neural pathways are “unmasked” or exposed and strengthened as they are used. The “unmasking” process is generally thought to be one of the principal ways in which the plastic brain reorganizes itself.”

Unmasking is probably at work in the astounding success some doctors have had in helping stroke victims with major lesions recover much of their lost function. In a technique called “constraint-induced” movement therapy (in which, for example, a patient’s good arm is put in a sling and good hand in an oven mitt, which then compels the patient to use the “paralyzed” arm), new areas of the brain are coaxed to take over the function of the region of the brain knocked out by the stroke. It is laborious therapy and it doesn’t work for every patient, but stroke victims disabled for many years have recovered the use of their limbs through constraint induced therapy and similar techniques have helped restore speech. It seems that the brain wants to repair itself.

It is important to underscore the kinds of changes we are talking about here. Neuroplasticity is not just a fancy name for the kind of synaptic changes that underlie learning and memory formation. Neuroplasticity goes beyond that. It produces wholesale changes in the job functions of particular areas of the brain. Cortical real estate that used to serve one purpose is reassigned and begins to do another. What this research shows is that the human brain continually remakes itself throughout life—in response to outside stimuli. Nature has equipped the human brain with the flexibility to adapt to the environment it encounters, the experiences it has, the damage it suffers and the demands its owner makes upon it. And, as I intimated earlier, it seems that the human brain can also be altered by what its owner thinks.

Two of the best illustrations of the power of self-directed thought to alter the brain come from experimental treatments for the psychological disorders of obsessive compulsive disorder and depression. Let’s look first at obsessive-compulsive disorder—OCD for short. In OCD, patients are barraged by upsetting, unwanted thoughts (obsessions) which lead to intense urges to perform ritualistic behaviors (compulsions.) Depending on the person, the compulsion might be to wash hands, to check door locks or check to see if the stove is off. Brain imaging studies show that OCD sufferers have hyperactivity in what’s been called the “worry circuit”—the circuit linking the orbital frontal cortex, which we might think of as the brain’s error detector, and the striatum which signals fear and dread. When this circuit fires repeatedly it bombards the sufferer with the feeling that something is horribly amiss and something must be done. Unfortunately, the something done—the compulsive activity—doesn’t stop the feeling. It’s as if this circuit has no neutral gear but is always in over drive. Oddly, most obsessive compulsive sufferers know full well that their hands aren’t dirty or they didn’t leave the stove on - it’s as if someone else has taken over their brain. OCD is extremely disruptive. It can take over a person’s life, making it impossible to hold a job or maintain relationships. It’s also extremely hard to treat. Even the newest drug treatments don’t significantly help a majority of sufferers. But neuroscientists at UCLA have developed a treatment that combines mindfulness meditation and cognitive therapy which shows extremely promising results. They taught patients to simply observe their obsessive thoughts without reacting emotionally to the discomfort they caused and then to tell themselves that the OCD urge was nothing more than a brain wiring defect, to say to themselves something like: “My brain is generating another obsessive thought. But I know it’s not real; it’s just a brain wiring problem.” After ten weeks of this mindfulness-based therapy, a majority of patients improved significantly, so much so that they felt liberated from their disease. And PET scans showed that activity in the orbital frontal cortex, the core of the worry circuit, had fallen dramatically compared to before the therapy. This research demonstrates that intentional, mindful effort can alter brain function - that self-directed neuroplastic changes are a reality.

A similar kind of mindfulness-based cognitive therapy has been used successfully with patients suffering from severe recurrent depression. People who suffer from depression also have an overactive pattern of brain activity in the frontal cortex. Sad thoughts or emotional setbacks, which everyone experiences from time to time, cascade into a descending spiral of negative, hopeless thinking from which the person cannot escape. Depression is also extremely debilitating and even though new drugs have provided innumerable people with relief, these drugs don’t work for everyone; they’re not without side effects; and, they don’t protect against relapse. In mindfulness-based cognitive therapy patients are taught to regard depressive thoughts as simply events in the mind rather than as absolute truths—as of no more significance than a butterfly floating into one’s field of vision—and to tell themselves that the thoughts do not reflect reality. In this approach negative thoughts are cut short rather than cascading into full blown depression. PET scans confirm that this kind of therapy permanently alters brain circuits, mutes the over-activity in the frontal cortex and corrects the chemical imbalances which lead to depression. Again, this shows that self-directed, mindful attention has the power to alter brain function.

This, my friends, is, if you’ll pardon the pun, mind-blowing science: the evidence that self-generated stimuli—thoughts and meditation—can permanently alter brain structure. Neuroroplasticity may lead to more effective treatments for all kinds of brain damage and any number of degenerative diseases, as well as effective treatments for psychological and cognitive disorders, thus improving the quality of life for millions of people. And that might be reason enough for us to learn about it as religious people. But I think it has even farther reaching implications for how to become those better people we yearn to be, for helping to build that better world of which we dream. It may, for example, provide the keys to overcoming those evolutionarily ingrained patterns of thought you’ve heard so much about from Mark that lead to such things as racism, greed or xenophobia. I’ll talk more about that two weeks from today. But for now, one thing seems clear. What we choose to focus on, what we pay attention to, does shape who we are. Our brains can change. We have the ability to nurture new qualities in ourselves until they become integral parts of our being which then direct our actions in the world. And isn’t this what the best of spiritual traditions have always taught? That what we pay attention to, what we set our minds on, is of utmost importance. And that brings us back to where we started. If there is to be peace in the world, it must begin with each and everyone of us. And so let us end with that beginning—by cultivating peace in ourselves so that we might bring peace to bear in our world.

Our closing hymn is really a meditation on peace—# 1009.

Major Sources:

Train Your Mind, Change Your Brain, Sharon Begley, New York: Ballantine Books, 2007
The Brain That Changes Itself , Norman Doidge, New York: Viking, 2007