Meditation increase Brain size & function(s)

Far from being simply a relaxed state, meditation is a period of heightened activity in the brain—one that can actually reshape your brain. People as diverse as David Lynch and the Dalai Lama have touted the benefits of meditation, claiming that it can increase attention, combat stress, foster compassion, and boost health. And in the past two decades, neuroscientists have begun to understand the biological substrates of these claims. Research suggests that long-term meditation increases the orbitofrontal cortex, the hippocampus, and the thalamus, potentially increasing one’s capacity for attention as well as compassion. 

People who meditate grow bigger brains than those who don’t.

Researchers at Harvard, Yale, and the Massachusetts Institute of Technology have found the first evidence that meditation can alter the physical structure of our brains. Brain scans they conducted reveal that experienced meditators boasted increased thickness in parts of the brain that deal with attention and processing sensory input.

In one area of gray matter, the thickening turns out to be more pronounced in older than in younger people. That’s intriguing because those sections of the human cortex, or thinking cap, normally get thinner as we age.

“Our data suggest that meditation practice can promote cortical plasticity in adults in areas important for cognitive and emotional processing and well-being,” says Sara Lazar, leader of the study and a psychologist at Harvard Medical School. “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.”

The researchers compared brain scans of 20 experienced meditators with those of 15 nonmeditators. Four of the former taught meditation or yoga, but they were not monks living in seclusion. The rest worked in careers such as law, health care, and journalism. All the participants were white. During scanning, the meditators meditated; the others just relaxed and thought about whatever they wanted.

Meditators did Buddhist “insight meditation,” which focuses on whatever is there, like noise or body sensations. It doesn’t involve “om,” other mantras, or chanting.

“The goal is to pay attention to sensory experience, rather than to your thoughts about the sensory experience,” Lazar explains. “For example, if you suddenly hear a noise, you just listen to it rather than thinking about it. If your leg falls asleep, you just notice the physical sensations. If nothing is there, you pay attention to your breathing.” Successful meditators get used to not thinking or elaborating things in their mind.

Study participants meditated an average of about 40 minutes a day. Some had been doing it for only a year, others for decades. Depth of the meditation was measured by the slowing of breathing rates. Those most deeply involved in the meditation showed the greatest changes in brain structure. “This strongly suggests,” Lazar concludes, “that the differences in brain structure were caused by the meditation, rather than that differences in brain thickness got them into meditation in the first place.”

Lazar took up meditation about 10 years ago and now practices insight meditation about three times a week. At first she was not sure it would work. But “I have definitely experienced beneficial changes,” she says. “It reduces stress [and] increases my clarity of thought and my tolerance for staying focused in difficult situations.”


Controlling random thoughts


Insight meditation can be practiced anytime, anywhere. “People who do it quickly realize that much of what goes on in their heads involves random thoughts that often have little substance,” Lazar comments. “The goal is not so much to ’empty’ your head, but to not get caught up in random thoughts that pop into consciousness.”

She uses this example: Facing an important deadline, people tend to worry about what will happen if they miss it, or if the end product will be good enough to suit the boss. You can drive yourself crazy with unproductive “what if” worry. “If, instead, you focus on the present moment, on what needs to be done and what is happening right now, then much of the feeling of stress goes away,” Lazar says. “Feelings become less obstructive and more motivational.”

The increased thickness of gray matter is not very much, 4 to 8 thousandths of an inch. “These increases are proportional to the time a person has been meditating during their lives,” Lazar notes. “This suggests that the thickness differences are acquired through extensive practice and not simply due to differences between meditators and nonmeditators.”

As small as they are, you can bet those differences are going to lead to lots more studies to find out just what is going on and how meditation might better be used to improve health and well-being, and even slow aging.

More basic questions need to be answered. What causes the increased thickness? Does meditation produce more connections between brain cells, or more blood vessels? How does increased brain thickness influence daily behavior? Does it promote increased communication between intellectual and emotional areas of the brain?

To get answers, larger studies are planned at Massachusetts General Hospital, the Harvard-affiliated facility where Lazar is a research scientist and where these first studies were done. That work included only 20 meditators and their brains were scanned only once.

“The results were very encouraging,” Lazar remarks. “But further research needs to be done using a larger number of people and testing them multiple times. We also need to examine their brains both before and after learning to meditate. Our group is currently planning to do this. Eventually, such research should reveal more about the function of the thickening; that is, how it affects emotions and knowing in terms of both awareness and judgment.”


Slowing aging?


Since this type of meditation counteracts the natural thinning of the thinking surface of the brain, could it play a role in slowing – even reversing – aging? That could really be mind-boggling in the most positive sense.

Lazar is cautious in her answer. “Our data suggest that one small bit of brain appears to have a slower rate of cortical thinning, so meditation may help slow some aspects of cognitive aging,” she agrees. “But it’s important to remember that monks and yogis suffer from the same ailments as the rest of us. They get old and die, too. However, they do claim to enjoy an increased capacity for attention and memory.”

But what is actually happening in the brain as we seek nirvana?

Meditators have long described their experiences as transformative states that are markedly different from normal consciousness, but only recently have researchers found the evidence to back this up.

Richard Davidson is one of the foremost researchers of meditation’s effects on the brain. A Harvard Ph.D graduate and a friend of the Dalai Lama, he was chided early in his career for wanting to study something as unscientific as meditation. But in 2004 he became an overnight scientific celebrity for discovering that Buddhist monks exhibit vastly different brainwaves during meditation than normal people. Brainwaves are produced as the billions of neurons in our brains transmit action potentials down their axons to the synapses where they trigger the release of neurotransmitters. These action potentials are essentially electrical charges that are passed from neuron to neuron. By placing sensors on the scalp, researchers can detect not the individual firings of neurons—they are far too small and numerous to differentiate—but the sum total of this electrical activity, dubbed brainwaves for their cyclical nature.

Using this electroencephalograph technology, Davidson asked his monks, each with 10,000 to 50,000 hours of meditation practice over their lifetimes, to concentrate on “unconditional loving-kindness and compassion.” A group of inexperienced meditators were also trained for one-week and then instructed to do the same. The results were dramatic, revealing two important things: first, the monks exhibited a higher ratio of high frequency gamma brainwaves to slower alpha and beta waves during their resting baseline before the experiment began; and when the monks engaged in meditation, this ratio skyrocketed—up to 30 times stronger than that of the non-meditators. In fact, the gamma activity measured in some of the practitioners was the highest ever reported in a non-pathological context. Not only did this suggest that long-term mental training could alter brain activity, it also suggested that compassion might be something that could be cultivated.

New neurobiological research bolsters the idea that meditation effects a permanent restructuring of the brain. In 2008 a team of researchers from UCLA led by Eileen Luderscompared the brains of long-term meditators with those of control subjects. In the brains of the meditators, they found larger volumes of gray matter in the right orbito-frontal cortex and the right hippocampus, areas thought to be implicated in emotion and response control. “It is likely that the observed larger hippocampal volumes may account for meditators’ singular abilities and habits to cultivate positive emotions, retain emotional stability, and engage in mindful behavior,” Luders writes. They also discovered a marked increase of gray matter in the thalamus, which is thought to act as the brain’s switchboard, relaying information between the cerebral cortex and subcortical areas. The change in size might allow for the meditators’ enhanced sense of focus during their practice.

And it turns out, you don’t have to be a yogi to reap the benefits of meditation. Even those who participate in short-term training courses can alter their brains, according to research published this summer: In a collaborative study between the University of Oregon and the Dalian University of Technology in China, neuroscientists discovered that a Chinese meditation technique called integrative body-mind training (IBMT) could alter the connectivity in the brain after just 11 hours of practice. Using a type of magnetic resonance called “diffusion tensor imaging,” the researchers examined the white matter fibers connecting different brain regions before and after training. The changes were most dramatic in the anterior cingulate, an area implicated in emotion control.

Brain Waves and Meditation

“Given the popularity and effectiveness of meditation as a means of alleviating stress and maintaining good health, there is a pressing need for a rigorous investigation of how it affects brain function,” says Professor Jim Lagopoulos of Sydney University, Australia. Lagopoulos is the principal investigator of a joint study between his university and researchers from the Norwegian University of Science and Technology (NTNU) on changes in electrical brain activity during nondirective meditation.

Constant brain waves

Whether we are mentally active, resting or asleep, the brain always has some level of electrical activity. The study monitored the frequency and location of electrical brain waves through the use of EEG (electroencephalography). EEG electrodes were placed in standard locations of the scalp using a custom-made hat

Participants were experienced practitioners of Acem Meditation, a nondirective method developed in Norway. They were asked to rest, eyes closed, for 20 minutes, and to meditate for another 20 minutes, in random order. The abundance and location of slow to fast electrical brain waves (delta, theta, alpha, beta) provide a good indication of brain activity.

Relaxed attention with theta

During meditation, theta waves were most abundant in the frontal and middle parts of the brain.

“These types of waves likely originate from a relaxed attention that monitors our inner experiences. Here lies a significant difference between meditation and relaxing without any specific technique,” emphasizes Lagopoulos.

“Previous studies have shown that theta waves indicate deep relaxation and occur more frequently in highly experienced meditation practitioners. The source is probably frontal parts of the brain, which are associated with monitoring of other mental processes.”

“When we measure mental calm, these regions signal to lower parts of the brain, inducing the physical relaxation response that occurs during meditation.”

Silent experiences with alpha

Alpha waves were more abundant in the posterior parts of the brain during meditation than during simple relaxation. They are characteristic of wakeful rest.

“This wave type has been used as a universal sign of relaxation during meditation and other types of rest,” comments Professor Øyvind Ellingsen from NTNU. “The amount of alpha waves increases when the brain relaxes from intentional, goal-oriented tasks.This is a sign of deep relaxation, — but it does not mean that the mind is void.”

Neuroimaging studies by Malia F. Mason and co-workers at Dartmouth College NH suggest that the normal resting state of the brain is a silent current of thoughts, images and memories that is not induced by sensory input or intentional reasoning, but emerges spontaneously “from within.”

“Spontaneous wandering of the mind is something you become more aware of and familiar with when you meditate,” continues Ellingsen, who is an experienced practitioner. “This default activity of the brain is often underestimated. It probably represents a kind of mental processing that connects various experiences and emotional residues, puts them into perspective and lays them to rest.”

Different from sleep

Delta waves are characteristic of sleep. There was little delta during the relaxing and meditative tasks, confirming that nondirective meditation is different from sleep.

Beta waves occur when the brain is working on goal-oriented tasks, such as planning a date or reflecting actively over a particular issue. EEG showed few beta waves during meditation and resting.

“These findings indicate that you step away from problem solving both when relaxing and during meditation,” says Ellingsen.

Nondirective versus concentration

Several studies indicate better relaxation and stress management by meditation techniques where you refrain from trying to control the content of the mind.

“These methods are often described as nondirective, because practitioners do not actively pursue a particular experience or state of mind. They cultivate the ability to tolerate the spontaneous wandering of the mind without getting too much involved. Instead of concentrating on getting away from stressful thought and emotions, you simple let them pass in an effortless way.”

Take home message

Nondirective meditation yields more marked changes in electrical brain wave activity associated with wakeful, relaxed attention, than just resting without any specific mental technique.

More Resources

—”Mental Training Enhances Attentional Stability: Neural and Behavioral Evidence,” (2009) published by Antoine Lutz in The Journal of Neuroscience [PDF]

—”Short-term meditation training improves attention and self-regulation,” (2007) published by Michael Posner in the journal PNAS

David Lynch on meditation [VIDEO]

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