Train Your Mind, Transform Your Brain
Neuroplasticity
In a real sense the brain we develop reflects the life we lead.
—THE DALAI LAMA1
In 2004, the fourteenth Dalai Lama, Tenzin Gyatso, invited five neuroscientists to Dharamsala, India. The main topic of this gathering was neuroplasticity: the dynamic potential of the brain to reorganize itself throughout life in response to everyday experience. Dozens of Tibetan Buddhist monks attended this meeting, which lasted five days. The neuroscientists unanimously supported the notion that mind is only a manifestation of electrical and chemical processes in the brain, and that there is no need to have recourse to anything spiritual or nonphysical to understand mental capacities. Expectedly, the Dalai Lama and the monks had a very different point of view.2
Despite their divergent beliefs, monks and scientists alike were enthusiastic about discussing the enticing possibility that mind shapes brain in foreseeable fashion, in much the same way as physical training reliably conditions muscles. The Dalai Lama expressed his profound conviction that thoughts and emotional feelings, while internal and intangible, can have a significant influence upon the activity and structure of the brain.
Neuroscientist Fred Gage, who attended the 2004 Dharamsala meeting, frames the traditional view of the brain in this way: “If the brain was changeable, then we would change. And if the brain made wrong changes, then we would change incorrectly. It was easier to believe there were no changes. That way, the individual would remain pretty much fixed.”3
Not all researchers welcomed the Dalai Lama into neuroscience with open arms. In 2005, when the Society for Neuroscience (SfN)—the largest professional society in the world for neuroscientists—notified members that the Dalai Lama had agreed to be the first-ever speaker in an annual lecture series, “Dialogues Between Neuroscience and Society,” at the upcoming fall meeting in Washington, D.C., it did not go unnoticed. Although his talk, “The Neuroscience of Meditation,” was designed to provide an opportunity for the Tibetan leader to promote the idea of a partnership between Buddhism and science, it soon ran into strong opposition.
Some neuroscientists urged SfN to cancel the lecture, and threatened to boycott the meeting. The Dalai Lama, they complained, is not qualified to talk about neuroscience. A researcher at the National Institutes of Health said, “We don’t want to mix science and religion in our children’s classrooms, and we don’t want it at a scientific meeting.” Another petition organizer was even more trenchant, asking, “Who’s coming next year? The Pope?”
The history of research into the brain’s capacity to change and grow with learning is not long. In the early 1960s Mark Rosenzweig, a research psychologist at the University of California–Berkeley, became one of the early pioneers of neuroplasticity. He and his fellow researchers found that rats raised in an enriched environment—cages filled with running wheels, toys to roll, and ladders to climb—were able to learn better than were genetically similar rats reared in an unenriched environment, bare of such objects. When they later examined the rats’ brains, the results were clear: the brains of the rats raised in the enriched environment weighed more and contained more chemical messengers than those from the rats reared in the unenriched environment.4
About thirty years later, in the late 1990s, Fred Gage and his colleagues at the Salk Institute compared the brains of two sets of aging mice—littermates raised in enriched and unenriched environments. They showed that the mice raised in the enriched environment were superior on tests evaluating exploration and learning, and that their brains displayed significantly more new neurons in the hippocampus compared with the brains of those raised in the unenriched environment. This important discovery indicates that environmental stimulation can promote neurogenesis—the generation of new neurons—even in an aging brain.5
Until the 1970s, it had been a central dogma of neuroscience that the adult brain was a static “hardwired” machine, with no ability to change and produce new neurons. Yet the scientific studies that led to the revolutionary discovery of neuroplasticity and other landmark studies have shown just the reverse: the adult human brain is continually changing its structure and function by creating new neurons and synaptic connections, and reorganizing existing neuronal networks or elaborating novel networks. We are not stuck with the brains we were born with. Just ask a London cabbie.
Drivers of London’s iconic black cabs can expect to earn almost twice as much as other cabbies—but it’s an arduous road to that reward. Would-be cabbies must become intimately acquainted with the multitude of streets and individual neighborhoods that lay inside a six-mile radius of Charing Cross in central London, and pass an intimidating oral test called “The Knowledge.” The study and training for the test is costly and takes drivers several years of hard work to complete. “The average student does 15 to 30 hours a week study, for three years,” according to The Observer.6 But once drivers earn the coveted license, they have done more than pass a test: they have changed the size of their brains.
In 2000, a research team at London’s University College led by Dr. Eleanor Maguire conducted magnetic resonance imaging (MRI) brain scans of sixteen London taxi drivers who had extensive navigation experience. The researchers compared the brains of these taxi drivers to those of control subjects who did not drive taxis. Maguire and her colleagues found compelling evidence that the brains of adults can, indeed, be physically changed by knowledge.
In each hemisphere of the brain, the posterior hippocampi of the taxi drivers were significantly larger than those of control subjects. The posterior hippocampus, located in the medial temporal lobe of the brain, consolidates information from short-term to long-term memory, plays a part in spatial navigation, and is thought to store a spatial representation of the environment. It is not surprising that this region was found to be even more developed in taxi drivers who had been in the career for several decades than in those who had been driving for a shorter span of time. Still, even the drivers were surprised. “I never noticed part of my brain growing,” said one. “It makes you wonder what happened to the rest of it.”7
What these findings suggest, say Maguire and her colleagues, is that the posterior part of the hippocampus can expand in people with a high dependence on navigational skills. Our brains are not fixed; they can grow and change over time, depending on how we use them. This supports the view of many neuroscientists that there is a capacity for regional plastic change in the structure of the adult human brain in response to demands of the environment. “This is the first study to show that the work you do can really change the structure of the brain,” said Maguire. “This insight into the plasticity of the human brain might offer hope for rehabilitation of neurologically injured patients.”8
It’s not only acquired knowledge that has an impact on neuroplasticity. Research has also shown that changes in thoughts and feelings have the power to transform the brain.
My research team and I demonstrated this some years ago with a group of young women suffering from arachnophobia. This irrational fear of spiders can be so intense as to trigger panic attacks, even when a living spider is not actually present. In our experiment, we asked these spider phobics to watch film excerpts of live spiders in motion while we scanned their brains with fMRI. All of the participants experienced intense fearful feelings as they watched the spiders on the screen, and the fMRI scans revealed that the fear reaction was associated with a strong activation of the hippocampal formation.
We know that phobias are characterized by phobic avoidance: if you are afraid of spiders, you will go to great lengths to get away from them. This impulse arises from an association of panic attacks with the context in which the fear reaction originally occurred. For example, if you became fearful of spiders because you encountered a nest of them inside a dark closet, the very act of opening a closet door may trigger a panic attack. The hippocampal formation plays an important role in the memory through which fear conditioning is established. Because the majority of the young women examined in our study developed a phobia following distressing childhood experiences with spiders, we proposed that the activation of the hippocampal formation was related to the emotional memories associated with these negative experiences.9
One week later, our phobics began a desensitization therapy designed to lessen their fear of spiders. The young women met for one three-hour group session each week for four weeks. The procedure was straightforward, gradually increasing education and exposure: The first week, they were asked to look at a book containing color pictures of spiders. The second week, they were shown film excerpts of living spiders, and were asked to look at the pictures and watch the film clips at home between sessions. The third week, they were asked to stay in a room that contained living spiders. During the fourth and last session, they were requested to touch a huge, live tarantula. All of the participants were able to do this successfully—quite remarkable, considering that before therapy, most were so phobic that they were unable to touch even pictures of spiders.
A week after the end of therapy, we again scanned the participants as they watched film excerpts of moving spiders. This time, the film excerpts did not produce fearful feelings, and the scans backed up their responses: they showed no activation of the hippocampal formation. These impressive findings suggest that the participants had functionally “rewired” their own brains, over a period of only a month, so that they no longer felt the fear that had restricted their lives.10 Coincidentally, about a year after the end of the study, I met one of the participants. She told me that after the study she had become very much enamored of spiders—so much so, that she had just adopted a giant tarantula as a pet.
Emotions can be very destructive; indeed, they constitute one of the main causes of human suffering. Fortunately, most of us are not at the mercy of our emotions but can modulate our emotional responses at will.
Back in 2001, I started a research program to explore what happens in the brain when healthy people are asked to take control of their emotions. In our first study, we asked ten young men to watch excerpts from erotic films. The participants were scanned with fMRI in a control condition and an experimental condition. In the control condition, they were instructed to simply watch the film excerpts and react normally. In the experimental condition, the men were requested to observe comparable but not identical film excerpts in a dispassionate, non-evaluative, and nonjudgmental way.
As expected, all of the participants were sexually aroused by the erotic film clips. In the control condition, sexual arousal was associated with activation in various brain structures known to be involved in emotions, such as the amygdala and the hypothalamus. The participants were all able to decrease their arousal in the experimental condition, and no activation was detected in these cerebral structures in response to the erotic videos.11
Later, my colleagues and I conducted another fMRI study using a similar approach.12 This time, however, we measured the brain activity of twenty psychologically healthy young women attempting to control sad feelings evoked by film excerpts. These excerpts featured the death of a beloved person. The women reported that they were able to reduce the sad feelings in the experimental condition. We found that the reduction of sad feelings was also accompanied by decreased activation in brain areas implicated in sadness.
The results of these studies indicate that normal people are not “feeling machines” who simply respond to stimuli. They are very much capable of controlling their reactions and the responses of their brains to emotional events.
Can mentally healthy people also influence the activity of chemical messengers that play a role in emotions? To investigate this crucial question, we used positron emission tomography (PET) to estimate the production of serotonin during rapid and sustained changes of emotional state.13 This chemical messenger is known to be crucially involved in mood and the control of emotion.
Seven healthy professional actors, all of them method actors, participated in our PET study. Method acting is a technique advocated by Lee Strasberg, famed director of the Actors Studio in New York City in the 1950s, and used by actors such as Marlon Brando, Dustin Hoffman, and many others. In this approach actors draw on their own emotions and emotional memories to power their portrayals. In contrast, more traditional forms of acting use techniques in which actors only simulate the emotions of their characters.
We asked the participating actors to self-induce transient states of sadness and happiness. To do so, they were instructed to relive and re-enact intense, genuine emotions associated with specific autobiographical memories. The actors underwent scanning sessions on separate days (one session for sadness, the other session for happiness). After each scanning session, they were asked to report the intensity of the emotions they experienced on a self-report scale.
All of the actors reported that they significantly experienced the target emotional states, and the PET results mirrored their subjective reports in distinct ways: the actors’ reported levels of sadness were correlated with a reduction of serotonin production in the brain’s emotional regions, such as the orbitofrontal cortex and the anterior cingulate cortex. In contrast, the intensity of the happy feelings was associated with increased serotonin production in emotional areas of the brain. These findings are consistent with the evidence indicating that serotonin activity is diminished in these areas in individuals with major depression.
The results of our brain imaging studies suggest that it is possible to rapidly influence brain chemicals related to emotions and mood, as well as the activity of the brain regions implicated in emotional reactions. If this is possible, then what results can mind and brain training have over the long term? A few curious neuroscientists, myself included, are currently on the road to find out.
Most people who have tried meditation, even casually, agree that it has a calming effect. Many people who meditate regularly would say that in general, they feel more peaceful and are able to think more clearly. But is it truly possible to make real changes to the brain simply by meditating regularly? The Dalai Lama believes it is. “It is a fundamental Buddhist principle that the human mind has a tremendous potential for transformation,” he has written. “Buddhist practitioners familiar with the workings of the mind have long been aware that it can be transformed through training. . . . In a real sense the brain we develop reflects the life we lead.”14
Science backs him up. A number of neuroscientific studies performed in recent years have demonstrated that willful attention and its training through the practice of meditation can indeed lead to important plastic changes in the brain. The broad term meditation refers to a large variety of mental training techniques that have been developed for various purposes, including fostering emotional balance and well-being.15 These techniques are generally classified into two types: mindfulness and concentrative. Mindfulness practices involve allowing any sensations, thoughts, or feelings to arise from moment to moment, while maintaining awareness as an attentive and nonattached observer without judgment or analysis. Such practices are part of ancient Eastern traditions of meditation such as Vipassana and Zen.16
Concentrative meditational practices involve focusing attention on specific body sensations (such as breath) and mental activity (such as a repeated sound or an imagined image). Examples include forms of yogic meditation and the Buddhist Shamatha meditation focus on the sensation of breath. Both mindfulness and concentrative techniques elicit a deep sense of calm peacefulness, a slowing of the mind’s internal dialogue, and a shift toward an expanded experience of self not centered on the meditator’s body representations and thoughts.17
Three decades ago, Jon Kabat-Zinn, a biomedical scientist at the University of Massachusetts Medical School and a student of Zen Master Seung Sahn, developed the Mindfulness-Based Stress Reduction (MBSR). MBSR is an eight-week intensive group program that brings together mindfulness meditation and yoga. Over the past thirty years, several thousands of people have taken the MBSR course, and studies have shown that MBSR significantly decreases stress symptoms in people with various types of cancer. Research has also demonstrated that MBSR reduces depression, rumination, and anxiety, and promotes well-being, compassion, and spirituality.
These potentially life-altering findings come as no surprise to longtime practitioners, including the Dalai Lama. Internationally recognized as a proponent of compassion, universal responsibility, and the nonviolent resolution of human conflict, he won the Nobel Prize for Peace in 1989. And he has always demonstrated a fervent interest in science, developing personal relationships with renowned physicists Carl von Weizsäcker and David Bohm and philosopher of science Karl Popper. The Tibetan leader has also participated in several conferences on science and spirituality. He is deeply convinced that science provides efficient means for understanding the basic interconnectedness of all life. He believes that science and Buddhism should both contribute to a better comprehension of the world: an important rationale for ethical behavior and environmental protection. In keeping with this conception, the Dalai Lama has asked Tibetan scholars to become familiar with science in order to rekindle the Tibetan philosophical tradition.
At the Alpbach Symposium on Consciousness in 1983, the Dalai Lama met Francisco Varela, the late Chilean-born neuroscientist who had become a Tibetan Buddhist in the 1970s. During that meeting, they began a discussion about consciousness and neuroscience. Varela agreed with the Dalai Lama that Buddhism represents an important source of observations concerning the human mind, with specific mental techniques to improve cognitive function and emotional well-being. Following this symposium Varela, in collaboration with Adam Engle—a lawyer and businessman, and also a Buddhist practitioner—created a series of meetings about Buddhism and science. These meetings, in-depth dialogues between the Dalai Lama and Western philosophers and scientists, formed the basis of what became the Mind & Life Institute. The first Mind & Life meeting was held in 1987 in Dharamsala, in northern India, the home of the Dalai Lama and of the exiled Tibetan government since Chinese troops invaded Tibet.18
Beginning in the 1990s, the Dalai Lama has arranged for Tibetan Buddhist monks with considerable meditation experience (at least 10,000 hours of practice) to travel to American universities to participate in brain-imaging studies. These studies seek to investigate whether Buddhist meditative techniques can produce lasting changes in the brain. So in 2005, when some scientists protested the Dalai Lama’s talk at the SfN conference, it came as something of a surprise.
A neuroscientist at the University of Florida, Jianguo Gu, helped to set up an online petition against the lecture: “I don’t think it’s appropriate to have a prominent religious leader at a scientific event,” he explained. “The Dalai Lama basically says the body and mind can be separated and passed to other people. There are no scientific grounds for that. We’ll be talking about cells and molecules and he’s going to talk about something that isn’t there.” (Although Gu and several of the scientists who started the protest are of Chinese origin, they stated that they were not against Buddhism. Rather, their main concern was to avoid entanglement with religion or politics, and confusion between objective inquiry and faith.19)
In the petition, the protestors asserted that
inviting the Dalai Lama to lecture on “Neuroscience of Meditation” is of poor scientific taste because it will highlight a subject with largely unsubstantiated claims and compromised scientific rigor and objectivity at a prestigious meeting attended by more than 20,000 neuroscientists. . . . It is ironic for neuroscientists to provide a forum for and, with it, implicit endorsement of a religious leader whose legitimacy relies on reincarnation, a doctrine against the very foundation of neuroscience. The present Dalai Lama explicitly claims the separation of mind and body, which is essential to the recognition of the Dalai Lama as both a religious and a political leader. It would serve the interests of SfN as well as the public to cancel the talk.20
Carol Barnes, the president of the SfN, responded, “The Dalai Lama has had a long interest in science and has maintained an ongoing dialogue with leading neuroscientists for more than fifteen years, which is the reason he was invited to speak at the meeting. It has been agreed that the talk will not be about religion or politics. We understand that not every member will agree with every decision and we respect their right to disagree.”21
Most protesters effectively boycotted the meeting and withdrew their conference papers. Acclaimed neuroscientist and one of the Dalai Lama’s primary scientific collaborators Richard Davidson was criticized by Yi Rao, a research neurologist at Northwestern University and a leader of the opponents to the Dalai Lama’s lecture. Rao said, “The motivations of both Davidson and the Dalai Lama are questionable.” He also accused Davidson of being a “politically involved scientist” who organized the Dalai Lama’s speech to confer scientific legitimacy to Buddhism. Davidson answered back that the opposition to the speech was obviously driven by the Chinese government’s long-running propaganda campaign against the Tibetan leader.
Davidson’s close personal relationship with the Dalai Lama has been questioned on the basis that scientists are supposed to keep professional distance from organizations and individuals supporting their research projects. Davidson responds that he greatly values his relationship with the Dalai Lama, and has no intention of giving it up. Some have pointed out that researchers gravitating around the Mind & Life Institute are at risk of losing their objectivity and influencing the results of their experiments by becoming acolytes of the Dalai Lama. About this, Charles Raison, a research psychiatrist at Emory University who has investigated the impact of meditation on the immune system, notes, “This is a field that has been populated by true believers. Many of the people doing this research are trying to prove scientifically what they already know from experience, which is a major flaw.” But Davidson contends that several scientists have profound personal interest in what they are studying, and this is a good thing.22
This was a contentious matter that threatened to upend the conference. And it also serves to reinforce an issue that we are investigating throughout this book: the tension between the restrictive dogmas of Western science and the free investigation of phenomena.
The notion of investigating what is going on in the brain during meditation is far from a new or even radical idea. In the 1950s pioneer researchers carried electroencephalography (EEG) devices up into the mountain caves of Indian yogis and conducted the first studies exploring brain activity during meditation. Since then, a number of EEG studies have been performed with various types of meditation techniques. These studies have revealed results concerning brain waves that have very interesting implications for all of us.
Research shows increases in alpha and theta activity during mindfulness meditative practices, such as Vipassana and Zen—not surprising, because increased alpha wave activity is thought to reflect relaxation, and theta waves are believed to be a specific marker of mindfulness meditative states. Some investigations of Zen meditation indicate that the magnitude of increases in theta activity is related to the level of expertise of the practitioners.23 Other EEG studies have shown that increased beta 2 (20 to 30 Hz) and gamma activity characterizes concentrative states of meditation. Beta 2 activity is reported during tasks involving focused attention; gamma activity is believed to be related to consciousness and the content of mental experience.24
Overall, the EEG studies of meditation conducted to date confirm the idea that different neuroelectrical signatures accompany different types of meditative practices. This makes a lot of sense, considering that different meditative practices are characterized by distinct mental processes and contents of experience.
In 2004, Richard Davidson, Antoine Lutz, and their colleagues at the University of Wisconsin–Madison published the results of an EEG study that received a lot of attention from the media.25 In that study, they recruited eight very experienced Tibetan Buddhist monks and ten novices (healthy student volunteers) who had had an introductory course in meditation. While the participants engaged in a form of meditation called nonreferential compassion, researchers measured their brain waves. During this kind of meditative state, meditators are asked to focus on unlimited compassion and loving kindness toward all living beings. Before the study, the novices had practiced this form of meditation for only one week (one hour daily). The Tibetan Buddhist monks had practiced nonreferential compassion for periods ranging from fifteen to forty years.
The researchers recorded exceptionally large increases in gamma waves in the monks for the nonreferential compassion state, compared with a resting state. These gamma waves were much more intense in the Tibetan monks than in the novices. Remarkably, higher gamma activity was still seen in the monks when they stopped meditating. Moreover, the more hours of meditation training a monk had had, the more robust and lasting the gamma activity. These findings suggest that meditative training may induce long-term changes in brain activity, even outside of meditation.26
That study was criticized on the ground that age could have accounted for some of the differences found: the monks investigated were twelve to forty-five years older than the university students. In addition, there was no way to know whether the monks had been adept at producing high gamma wave activity before they ever began meditating. Nonetheless, the results of this study are intriguing.
In another study, the research team led by Richard Davidson used fMRI to examine what happens in the brain during ‘‘one-pointed concentration,’’ a form of meditation that is practiced to increase attentional focus and reach a peaceful state in which preoccupation with thoughts and emotions is progressively diminished.27 They compared a group of Tibetan Buddhist monks with extensive meditation experience to a group of age-matched novice meditators. Davidson and his colleagues found that activation in brain regions normally implicated in sustained attention was generally more robust for the expert meditators compared to novices. However, whereas the monks with an average of 19,000 hours of practice exhibited greater activation in these regions than the novices, those monks with an average of 44,000 practice hours showed less activation. This fits well with meditation texts that present concentration meditation as requiring at first higher levels of effortful concentration but eventually becoming less effortful, such that later phases of this meditative practice necessitate minor effort.
Davidson and his colleagues have also used fMRI to measure brain activity while Tibetan monks and novices voluntarily produced a loving-kindness and compassion meditation state.28 These researchers saw greater activation of brain areas implicated in empathy in the monks, compared to the novices. This finding demonstrates that the mental expertise to self-induce positive emotion alters the activation of cerebral structures known to be involved in empathic responses.
Recently, Véronique Taylor, a master’s student in my lab at the University of Montreal, conducted an fMRI study to explore the effects of mindfulness meditation on the brain responses to emotionally evocative color pictures.29 Another goal of this study was to examine the impact of the duration of mindfulness training on the brain responses to such pictures. Experienced meditators with more than 1,000 hours of experience in Zen meditation were compared to novice meditators. Novices were instructed to practice mindfulness meditation twenty minutes per day for seven days before the experiment. The two groups of participants were scanned as they viewed negative, positive, and neutral pictures in a mindful state and a nonmindful state of awareness.
Both groups subjectively perceived the pictures viewed in a mindful state as less intense than when viewed in a nonmindful state. Furthermore, in experienced meditators, mindfulness was accompanied by decreased activation in brain regions typically associated with emotional reactivity. These results support the view that mindfulness meditation eases the impact of emotional triggers. Our results also suggest that with extensive training, mindfulness meditation may promote a state of mental calmness by quieting brain activity.
Can the practice of meditation also lead to changes in the actual structure of the brain? A few years ago, research psychologist Sara Lazar and her colleagues at Harvard University decided to tackle this important question using structural MRI. This method provides the most accurate information regarding the anatomy of the brain. Lazar and her co-workers showed that the long-term practice of meditation is indeed associated with changes in the brain’s physical structure.
They compared anatomical brain scans of fifteen non-meditators to those of twenty experienced meditators who had an average of nearly 3,000 hours of mindfulness practice. Increased thickness of gray matter was found in brain regions associated with attention and interoception, the capacity to consciously detect changes occurring within the body.30
“Our data suggest that meditation practice can promote plasticity in adults in areas important for cognitive and emotional processing and well-being,” said Lazar. “These findings are consistent with other studies that demonstrated increased thickness of music areas in the brains of musicians, and visual and motor areas in the brains of jugglers. In other words, the structure of an adult brain can change in response to repeated practice.” Lazar also noted that the increases in gray matter thickness were proportional to the time the meditators had been practicing mindfulness.31
Britta Hölzel, another research psychologist at Harvard University, has conducted a structural MRI study to measure gray matter changes induced by the MBSR program.32 Anatomical scans from sixteen meditation-naïve participants were obtained before and after they underwent MBSR. The MBSR group was compared with a control group of seventeen individuals who did not practice meditation. Participants in the MBSR group meditated for about forty-five minutes a day for eight weeks. In participants who received MBSR, increases in gray matter density were measured in brain regions implicated in learning and memory, empathy, and emotion regulation—that is, the ability to engage in healthy strategies to manage disagreeable emotions when necessary. No such changes were seen in the control group.
In yet another study, neuroscientists Giuseppe Pagnoni and Milos Cekic at Emory University in Atlanta, Georgia, have used structural MRI to examine how the regular practice of meditation may affect the normal age-related decline of cerebral gray matter volume and attentional performance seen in healthy people.33 Gray matter volume has been shown to decrease immediately after adolescence.
Pagnoni and Cekic recruited regular practitioners of Zen meditation who had more than three years of daily practice, and control subjects who had never practiced meditation. The two groups were matched by gender, level of education, and age (thirty-seven years for the meditators, thirty-five years for the control subjects); they all participated in a task assessing vigilance, a sustained form of attention.
The expected negative correlation of gray matter volume and attentional performance with age was found in the control subjects; no such correlation was detected in the meditators. In addition, gray matter volume in the putamen, a cerebral structure involved in attention, was positively correlated with performance on the vigilance task. These findings suggest that the regular practice of Zen meditation may offer protection from cognitive decline through inhibition of the reduction in both gray matter volume and attentional performance associated with normal aging.
There is now evidence that meditation can also lead to changes in white matter, which is responsible for communication among the various regions of the brain. About this issue, Yi-Yuan Tang of Dalian University of Technology in China, University of Oregon (UO) psychologist Michael Posner, and their colleagues have used a type of MRI technique called diffusion tensor imaging (or DTI) to examine the impact of meditation on white-matter connectivity between cerebral structures.
In this study, forty-five UO students were divided in two groups. In one group, twenty-two students received eleven hours of integrative body–mind training (IBMT), an approach based on traditional Chinese medicine that involves mindfulness, mental imagery, and body relaxation. In the other (control) group, twenty-three students received the same amount of relaxation training involving the relaxing of muscle groups over the face, head, shoulders, arms, legs, chest, back, and abdomen. The participants were scanned before and after training. A comparison of the scans taken of the participants’ brains before and after the training showed that those in the IBMT group had increased connections in the area of the anterior cingulate cortex, a region that plays an important role in attention and the regulation of emotions. White-matter changes were not observed in the control group.34
So far, most brain imaging studies of meditation have not enabled researchers to determine whether differences between experienced meditators and novices existed before the studies. One way to address this vital issue is to investigate novice meditators and matched nonmeditator controls and follow them prospectively through time. Such a methodological strategy has been used by the scientists leading the Shamatha Project, the most extensive investigation to date regarding the benefits to mental and physical health of intensive meditation practice. This project, which is headed by Clifford Saron, a neuroscientist at the University of California–Davis, investigates the psychological and physiological processes underlying the long-term beneficial effects of meditation. Funded by the Fetzer Institute and the Hershey Family Foundation, the Shamatha Project involves a team of several psychologists and neuroscientists from universities across the United States and Europe.
In this project, sixty healthy people with varying degrees of prior meditation experience were randomly assigned to an intensive three-month meditation retreat or a control group. The control participants later followed a similar three-month retreat. Perceptual, cognitive, and emotional tasks, as well as questionnaires and physiological tests, were used to assess participants before, during, and after their retreats. During the retreat, participants received instruction in meditative techniques aimed at refining attention, and developing compassion and kindness toward others. Participants practiced alone about six hours a day over the three-month period. Meditation instructions were given by B. Alan Wallace, who combines fourteen years of training as a Tibetan Buddhist monk with degrees in physics, the philosophy of science, and religious studies. Founder and president of the Santa Barbara Institute for Consciousness Studies, Wallace is currently one of the main proponents of the integration of Buddhist contemplative practices and Western science to move forward the study of the mind and consciousness.
The initial results indicate that intensive meditative training enhances attention, improves well-being, and promotes more empathic emotional response to the suffering of others. These positive changes endured at least five months after the retreat. The data related to the impact of the meditative techniques on brain activity are currently being analyzed and should be published soon.35
Since the beginning of neuroscience in the nineteenth century, neuroscientists thought that we are “stuck” with the brain we are born with because they conceived this part of the central nervous system as a stable, hardwired machine. With the discovery of neuroplasticity, however, it became clear that this belief was deeply flawed. Indeed, researchers have found out that the adult brain is highly malleable.
Today, this evidence is impossible to ignore. Research has shown that we can intentionally train our minds, through meditative practices, to bolster the activity of regions and circuits of our brains involved not only in attention and concentration, but in empathy, compassion, and emotional well-being. Such mental exercises can even modify the physical structure of the brain. Changes in thoughts, beliefs, and emotions, made in the context of psychotherapy, also have the power to transform the brain, as shown by neuroimaging studies. Additionally, there is now some evidence that mental training can slow down the cognitive decline and reduction in gray matter volume typically seen in normal aging. These cutting-edge findings are great news. They invite us all to unleash the full potential of the mind, the immense power that sits within us.
Can we use the power of our minds to cure disease? In one study of this question, Dr. Carl Simonton and his colleagues taught patients to visualize their bodies in perfect working order and mentally imagine white blood cells as sharks devouring and eliminating the cancer cells, imagined as shark bait.36 Results revealed increased life expectancy, better pain management, more positive attitude and self-images, and reduced tumor size and incidence for those patients who used the visualization technique. Similar results were found in other studies. In the next chapter we look at these and other intriguing interactions among the mind, the brain, and the body, and the very real curative potential that exists within us.