A number of recent significant studies have shown that regular meditation physically alters the brains of participants, and the effect lasts long after meditation periods.
A new study has found that participating in an 8-week meditation training program can have measurable effects on how the brain functions even when someone is not actively meditating. In their report in the November issue of Frontiers in Human Neuroscience, investigators at Massachusetts General Hospital (MGH), Boston University (BU), and several other research centers also found differences in those effects based on the specific type of meditation practiced.
“The two different types of meditation training our study participants completed yielded some differences in the response of the amygdala — a part of the brain known for decades to be important for emotion — to images with emotional content,” says Gaëlle Desbordes, PhD, a research fellow at the Athinoula A. Martinos Center for Biomedical Imaging at MGH and at the BU Center for Computational Neuroscience and Neural Technology, corresponding author of the report. “This is the first time that meditation training has been shown to affect emotional processing in the brain outside of a meditative state.”
Several previous studies have supported the hypothesis that meditation training improves practitioners’ emotional regulation. While neuroimaging studies have found that meditation training appeared to decrease activation of the amygdala — a structure at the base of the brain that is known to have a role in processing memory and emotion — those changes were only observed while study participants were meditating. The current study was designed to test the hypothesis that meditation training could also produce a generalized reduction in amygdala response to emotional stimuli, measurable by functional magnetic resonance imaging (fMRI).
Participants had enrolled in a larger investigation into the effects of two forms of meditation, based at Emory University in Atlanta. Healthy adults with no experience meditating participated in 8-week courses in either mindful attention meditation — the most commonly studied form that focuses on developing attention and awareness of breathing, thoughts and emotions — and compassion meditation, a less-studied form that includes methods designed to develop loving kindness and compassion for oneself and for others. A control group participated in an 8-week health education course.
Within three weeks before beginning and three weeks after completing the training, 12 participants from each group traveled to Boston for fMRI brain imaging at the Martinos Center’s state-of-the-art imaging facilities. Brain scans were performed as the volunteers viewed a series of 216 different images — 108 per session — of people in situations with either positive, negative or neutral emotional content. Meditation was not mentioned in pre-imaging instructions to participants, and investigators confirmed afterwards that the volunteers had not meditated while in the scanner. Participants also completed assessments of symptoms of depression and anxiety before and after the training programs.
In the mindful attention group, the after-training brain scans showed a decrease in activation in the right amygdala in response to all images, supporting the hypothesis that meditation can improve emotional stability and response to stress. In the compassion meditation group, right amygdala activity also decreased in response to positive or neutral images. But among those who reported practicing compassion meditation most frequently outside of the training sessions, right amygdala activity tended to increase in response to negative images — all of which depicted some form of human suffering. No significant changes were seen in the control group or in the left amygdala of any study participants.
“We think these two forms of meditation cultivate different aspects of mind,” Desbordes explains. “Since compassion meditation is designed to enhance compassionate feelings, it makes sense that it could increase amygdala response to seeing people suffer. Increased amygdala activation was also correlated with decreased depression scores in the compassion meditation group, which suggests that having more compassion towards others may also be beneficial for oneself. Overall, these results are consistent with the overarching hypothesis that meditation may result in enduring, beneficial changes in brain function, especially in the area of emotional processing.”
Scientists have mostly focused on the benefits of meditation for the brain and the body, but a recent study by Northeastern University’s David DeSteno, published in Psychological Science, takes a look at what impacts meditation has on interpersonal harmony and compassion.
Several religious traditions have suggested that mediation does just that, but there has been no scientific proof — until now.
In this study, a team of researchers from Northeastern University and Harvard University examined the effects meditation would have on compassion and virtuous behavior, and the results were fascinating.
This study — funded by the Mind and Life Institute — invited participants to complete eight-week trainings in two types of meditation. After the sessions, they were put to the test.
Sitting in a staged waiting room with three chairs were two actors. With one empty chair left, the participant sat down and waited to be called. Another actor using crutches and appearing to be in great physical pain, would then enter the room. As she did, the actors in the chair would ignore her by fiddling with their phones or opening a book.
The question DeSteno and Paul Condon — a graduate student in DeSteno’s lab who led the study — and their team wanted to answer was whether the subjects who took part in the meditation classes would be more likely to come to the aid of the person in pain, even in the face of everyone else ignoring her. “We know meditation improves a person’s own physical and psychological wellbeing,” said Condon. “We wanted to know whether it actually increases compassionate behavior.”
Among the non-meditating participants, only about 15 percent of people acted to help. But among the participants who were in the meditation sessions “we were able to boost that up to 50 percent,” said DeSteno. This result was true for both meditation groups thereby showing the effect to be consistent across different forms of meditation. “The truly surprising aspect of this finding is that meditation made people willing to act virtuous — to help another who was suffering — even in the face of a norm not to do so,” DeSteno said, “The fact that the other actors were ignoring the pain creates as ‘bystander-effect’ that normally tends to reduce helping. People often wonder ‘Why should I help someone if no one else is?'”
These results appear to prove what the Buddhist theologians have long believed — that meditation is supposed to lead you to experience more compassion and love for all sentient beings. But even for non-Buddhists, the findings offer scientific proof for meditation techniques to alter the calculus of the moral mind.
Earlier evidence out of UCLA suggested that meditating for years thickens the brain (in a good way) and strengthens the connections between brain cells. Now a further report by UCLA researchers suggests yet another benefit.
Eileen Luders, an assistant professor at the UCLA Laboratory of Neuro Imaging, and colleagues, have found that long-term meditators have larger amounts of gyrification (“folding” of the cortex, which may allow the brain to process information faster) than people who do not meditate. Further, a direct correlation was found between the amount of gyrification and the number of meditation years, possibly providing further proof of the brain’s neuroplasticity, or ability to adapt to environmental changes.
The article appears in the online edition of the journal Frontiers in Human Neuroscience.
The cerebral cortex is the outermost layer of neural tissue. Among other functions, it plays a key role in memory, attention, thought and consciousness. Gyrification or cortical folding is the process by which the surface of the brain undergoes changes to create narrow furrows and folds called sulci and gyri. Their formation may promote and enhance neural processing. Presumably then, the more folding that occurs, the better the brain is at processing information, making decisions, forming memories and so forth.
“Rather than just comparing meditators and non-meditators, we wanted to see if there is a link between the amount of meditation practice and the extent of brain alteration,” said Luders. “That is, correlating the number of years of meditation with the degree of folding.”
Of the 49 recruited subjects, the researchers took MRI scans of 23 meditators and compared them to 16 control subjects matched for age, handedness and sex. (Ten participants dropped out.) The scans for the controls were obtained from an existing MRI database, while the meditators were recruited from various meditation venues. The meditators had practiced their craft on average for 20 years using a variety of meditation types — Samatha, Vipassana, Zen and more. The researchers applied a well-established and automated whole-brain approach to measure cortical gyrification at thousands of points across the surface of the brain.
They found pronounced group differences (heightened levels of gyrification in active meditation practitioners) across a wide swatch of the cortex, including the left precentral gyrus, the left and right anterior dorsal insula, the right fusiform gyrus and the right cuneus.
Perhaps most interesting, though, was the positive correlation between the number of meditation years and the amount of insular gyrification.
“The insula has been suggested to function as a hub for autonomic, affective and cognitive integration,” said Luders. “Meditators are known to be masters in introspection and awareness as well as emotional control and self-regulation, so the findings make sense that the longer someone has meditated, the higher the degree of folding in the insula.”
While Luders cautions that genetic and other environmental factors could have contributed to the effects the researchers observed, still, “The positive correlation between gyrification and the number of practice years supports the idea that meditation enhances regional gyrification.”
Two years ago, researchers at UCLA found that specific regions in the brains of long-term meditators were larger and had more gray matter than the brains of individuals in a control group. This suggested that meditation may indeed be good for all of us since, alas, our brains shrink naturally with age.
Now, a follow-up study suggests that people who meditate also have stronger connections between brain regions and show less age-related brain atrophy. Having stronger connections influences the ability to rapidly relay electrical signals in the brain. And significantly, these effects are evident throughout the entire brain, not just in specific areas.
Eileen Luders, a visiting assistant professor at the UCLA Laboratory of Neuro Imaging, and colleagues used a type of brain imaging known as diffusion tensor imaging, or DTI, a relatively new imaging mode that provides insights into the structural connectivity of the brain. They found that the differences between meditators and controls are not confined to a particular core region of the brain but involve large-scale networks that include the frontal, temporal, parietal and occipital lobes and the anterior corpus callosum, as well as limbic structures and the brain stem.
The study appears in the current online edition of the journal NeuroImage.
“Our results suggest that long-term meditators have white-matter fibers that are either more numerous, more dense or more insulated throughout the brain,” Luders said. “We also found that the normal age-related decline of white-matter tissue is considerably reduced in active meditation practitioners.”
The study consisted of 27 active meditation practitioners (average age 52) and 27 control subjects, who were matched by age and sex. The meditation and the control group each consisted of 11 men and 16 women. The number of years of meditation practice ranged from 5 to 46; self-reported meditation styles included Shamatha, Vipassana and Zazen, styles that were practiced by about 55 percent of the meditators, either exclusively or in combination with other styles.
Results showed pronounced structural connectivity in meditators throughout the entire brain’s pathways. The greatest differences between the two groups were seen within the corticospinal tract (a collection of axons that travel between the cerebral cortex of the brain and the spinal cord); the superior longitudinal fasciculus (long bi-directional bundles of neurons connecting the front and the back of the cerebrum); and the uncinate fasciculus (white matter that connects parts of the limbic system, such as the hippocampus and amygdala, with the frontal cortex).
“It is possible that actively meditating, especially over a long period of time, can induce changes on a micro-anatomical level,” said Luders, herself a meditator.
As a consequence, she said, the robustness of fiber connections in meditators may increase and possibly lead to the macroscopic effects seen by DTI.
“Meditation, however, might not only cause changes in brain anatomy by inducing growth but also by preventing reduction,” Luders said. “That is, if practiced regularly and over years, meditation may slow down aging-related brain atrophy, perhaps by positively affecting the immune system.”
But there is a “but.” While it is tempting to assume that the differences between the two groups constitute actual meditation-induced effects, there is still the unanswered question of nature versus nurture.
“It’s possible that meditators might have brains that are fundamentally different to begin with,” Luders said. “For example, a particular brain anatomy may have drawn an individual to meditation or helped maintain an ongoing practice — meaning that the enhanced fiber connectivity in meditators constitutes a predisposition towards meditation, rather than being the consequence of the practice.”
Still, she said, “Meditation appears to be a powerful mental exercise with the potential to change the physical structure of the brain at large. Collecting evidence that active, frequent and regular meditation practices cause alterations of white-matter fiber tracts that are profound and sustainable may become relevant for patient populations suffering from axonal demyelination and white-matter atrophy.”
Experienced Zen meditators can clear their minds of distractions more quickly than novices, according to a new brain imaging study.
After being interrupted by a word-recognition task, experienced meditators’ brains returned faster to their pre-interruption condition, researchers at Emory University School of Medicine found.
Giuseppe Pagnoni, PhD, Emory assistant professor of psychiatry and behavioral sciences, and co-workers used functional magnetic resonance imaging (fMRI) to examine changes in blood flow in the brain when people meditating were interrupted by stimuli designed to mimic the appearance of spontaneous thoughts.
The study compared 12 people from the Atlanta area with more than three years of daily practice in Zen meditation with 12 others who had never practiced meditation.
While having their brains scanned, the subjects were asked to focus on their breathing. Every once in a while, they had to distinguish a real word from a nonsense word presented at random intervals on a computer screen and, having done that, promptly “let go” of the just processed stimulus by refocusing on their breath.
The authors found that differences in brain activity between experienced meditators and novices after interruption could be seen in a set of areas often referred to as the “default mode network.” Previous studies have linked the default mode network with the occurrence of spontaneous thoughts and mind-wandering during wakeful rest.
After interruption, experienced meditators were able to bring activity in most regions of the default network back to baseline faster than non-meditators. This effect was especially prominent in the angular gyrus, a region important for processing language.
“This suggests that the regular practice of meditation may enhance the capacity to limit the influence of distracting thoughts. This skill could be important in conditions such as attention deficit and hyperactivity disorder, obsessive-compulsive disorder, anxiety disorder and major depression, characterized by excessive rumination or an abnormal production of task-unrelated thoughts,” Pagnoni says.