By Jennifer Gibson, PharmD, practicing clinical pharmacist and freelance medical writer.
Source: BrainBlogger, a biomedical blog that covers topics from multidimensional biopsychosocial perspectives.
Yoga is a practice almost as old as time itself. It combines mental and physical elements that people today use to enhance spirituality, exercise, decrease stress, and increase well-being. While many practitioners of yoga seem almost mystical and more philosophical than the average bear, a new study proves that you need not be a yogi to achieve the anti-anxiety benefits of yoga.
Research published in the Journal of Alternative and Complementary Medicine reports that practicing yoga postures increased the levels of gamma-aminobutyric acid (GABA) in the brain. (GABA is a neurotransmitter in the central nervous system that is responsible for reduced anxiety, increased relaxation, and enhanced muscle tone.) In this study, healthy subjects with no significant physical or psychiatric illnesses or conditions participated in 60-minute yoga sessions 3 times weekly for 12 weeks. Alternatively, a comparison group participated in a metabolically matched walking program for the same length of time. Subjective mood and anxiety measurements were recorded, and magnetic resonance spectroscopy scans were completed at baseline and at 12 weeks.
Overall, yoga participants experienced greater improvement in mood and decrease in anxiety, compared to the walking group. More objectively, yoga participants showed increased levels of GABA in the brain. Positive correlations were observed between improved mood and decreased anxiety and GABA levels. This appears to be the first time that long-term behavioral interventions have produced increased GABA levels. (A similar pilot study showed that a single yoga session increased GABA levels.) Pharmacological agents are frequently used to increase GABA activity in order to reduce anxiety and improve mood. Yoga, in contrast to pharmacological agents, carries almost no risk of adverse consequences and costs very little, if anything, to practice.
In addition to decreasing anxiety, yoga and other mindfulness-based techniques improve stress, depression, overall well-being, neuroticism, eating habits, energy levels, and pain. Yoga has been prescribed for arthritis and other joint and muscle disorders, with strikingly positive benefits. Yoga also promotes immune function, weight loss, decreased heart rate and blood pressure, and muscle strength. Yoga has even been shown to decrease premature delivery when practiced by women during pregnancy. While other forms of exercise bring about the same benefits, yoga has shown more robust benefits than other activities.
With seemingly all the benefits and none of the risks, yoga should be explored as part of a treatment plan for individuals with mood and anxiety disorders. Or, for anyone wishing to improve well-being. So, grab a yoga mat and strike a pose. Namaste.
References
Field T (2011). Yoga clinical research review. Complementary therapies in clinical practice, 17 (1), 1-8 PMID: 21168106
Haaz S, & Bartlett SJ (2011). Yoga for arthritis: a scoping review. Rheumatic diseases clinics of North America, 37 (1), 33-46 PMID: 21220084
Smith BW, Shelley BM, Dalen J, Wiggins K, Tooley E, & Bernard J (2008). A pilot study comparing the effects of mindfulness-based and cognitive-behavioral stress reduction. Journal of alternative and complementary medicine (New York, N.Y.), 14 (3), 251-8 PMID: 18370583
Streeter CC, Jensen JE, Perlmutter RM, et al. Yoga Asana sessions increase brain GABA levels: a pilot study. J Altern Complement Med. May 2007;13(4):419-426. PMID: 17532734
Streeter CC, Whitfield TH, Owen L, Rein T, Karri SK, Yakhkind A, Perlmutter R, Prescot A, Renshaw PF, Ciraulo DA, & Jensen JE (2010). Effects of yoga versus walking on mood, anxiety, and brain GABA levels: a randomized controlled MRS study. Journal of alternative and complementary medicine (New York, N.Y.), 16(11), 1145-52 PMID: 20722471
Sonja Kotz leads the Minerva research group "Neurocognition of Rhythm in Communication" at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig. She presented evidence from neuroimaging on the impact of cognitive functions on bilingual processing at the AAAS symposium "Crossing Borders in Language Science: What Bilinguals Tell Us About Mind and Brain".
Rhythm, as the recurrent patterning of events in time, underlies most human behavior such as speech, music, and body movements. Sonja Kotz investigates how temporal patterns in di!erent languages influence the processing of phonological, semantic, and syntactic information. Individuals who learn a new language usually need time to develop a "feel" for its characteristics. With rapid speech it can initially even be difficult to recognize individual words. "This is because the brain has to become accustomed to new speech rhythms," explains Sonja Kotz.
Our brain is very good at recognizing patterns in the environment and uses them to create general predictions about the near future.
"We assume there is a neural network permanently engaged in evaluating information about duration, rhythm, tempo and stress of syllables in order to recognize temporal regularities in the stream of speech", says Kotz. During language acquisition, this network could store fundamental regularities of speech in the brain so that later, language processing is more efficient.
Rhythm processing predominantly occurs in brain areas in and just belowthe cerebral cortex but also in motor areas and evolutionarily older areas like the cerebellum and basal ganglia.
"This points to an early stage of development," says Kotz. "The evolution of language would not have been possible without the development of brain areas which have the ability to structure events temporally." To meet the high communicative demands of homo sapiens, the motor system in and below the cerebral cortex might have become increasingly sensitive to rhythmic input.
Thoughts and actions are intimately linked, and the mere thought of an action is much like actually performing it. The brain prepares for an action by generating a motor simulation of it, praticising its execution of the movements by going through the motions invisibly. Seeing a manipulable object such as a tool, for example, automatically triggers a simulation of using it - a mental image of reaching out and grasping it with the hand that is nearest to the handle.
Motor simulations and movements are known to influence thought processes. Magnetic stimulation of the motor cortex influences the processing of words related to arm and leg action, whereas polonged movements in one direction slow the comprehension of sentences related to movements in the other. Psychologist Jessica Witt of the Action-Modulated Perception Laboratory at Purdue University and her colleagues now provide further evidence of this link - in a study published online in the journal Psychological Science, they show that motor simulations may enhance the recognition of tools.
How you answer questions like these, it turns out, may determine how long it will take for you to decipher what you're reading, solve your puzzle, or get your keys back.
The brain is often envisioned as something like a computer, and the body as its all-purpose tool. But a growing body of new research suggests that something more collaborative is going on - that we think not just with our brains, but with our bodies. A series of studies, the latest published in November, has shown that children can solve math problems better if they are told to use their hands while thinking. Another recent study suggested that stage actors remember their lines better when they are moving. And in one study published last year, subjects asked to move their eyes in a specific pattern while puzzling through a brainteaser were twice as likely to solve it.
The term most often used to describe this new model of mind is "embodied cognition," and its champions believe it will open up entire new avenues for understanding - and enhancing - the abilities of the human mind. Some educators see in it a new paradigm for teaching children, one that privileges movement and simulation over reading, writing, and reciting. Specialists in rehabilitative medicine could potentially use the emerging findings to help patients recover lost skills after a stroke or other brain injury. The greatest impact, however, has been in the field of neuroscience itself, where embodied cognition threatens age-old distinctions - not only between brain and body, but between perceiving and thinking, thinking and acting, even between reason and instinct - on which the traditional idea of the mind has been built.
"It's a revolutionary idea," says Shaun Gallagher, the director of the cognitive science program at the University of Central Florida. "In the embodied view, if you're going to explain cognition it's not enough just to look inside the brain. In any particular instance, what's going on inside the brain in large part may depend on what's going on in the body as a whole, and how that body is situated in its environment."
The emerging field builds on decades of research into human movement and gesture. Much of the earlier work looked at the role of gestures in communication, asking whether gesture grew out of speech or exploring why people gestured when they were talking on the telephone.
But today, neuroscientists, linguists, and philosophers are making much bolder claims. A few argue that human characteristics like empathy, or concepts like time and space, or even the deep structure of language and some of the most profound principles of mathematics, can ultimately be traced to the idiosyncrasies of the human body. If we didn't walk upright, for example, or weren't warm-blooded, they argue, we might understand these concepts totally differently. The experience of having a body, they argue, is intimately tied to our intelligence.
"If you want to teach a computer to play chess, or if you want to design a search engine, the old model is OK," says Rolf Pfeifer, director of the artificial intelligence lab at the University of Zurich, "but if you're interested in understanding real intelligence, you have to deal with the body."
Embodied cognition upends several centuries of thinking about thinking. Rene Descartes, living in an age when steam engines were novelty items, envisioned the brain as a pump that moved "animating fluid" through the body - head-shrinkers through the ages have tended to enlist the high-tech of their day to describe the human cognitive system - but the mind, Descartes argued, was something else entirely, an incorporeal entity that interacted with the body through the pineal gland.
While a few thinkers, most notably the French philosopher Maurice Merleau-Ponty in the 1940s, challenged Descartes' mind-body separation, it remained the dominant model up through the 20th century, though its form evolved with the times. After the development of the modern computer in the years after World War II, a new version of the same model was adopted, with the brain as a computer and the mind as the software that ran on it.
In the 1980s, however, a group of scholars began to contest this approach. Fueled in part by broad disappointment with artificial-intelligence research, they argued that human beings don't really process information the way computers do, by manipulating abstract symbols using formal rules. In 1995, a major biological discovery brought even more enthusiasm to the field. Scientists in Italy discovered "mirror neurons" that respond when we see someone else performing an action - or even when we hear an action described - as if we ourselves were performing the action. By simultaneously playing a role in both acting and thinking, mirror neurons suggested that the two might not be so separate after all.
"You were seeing the same system, namely the motor system, playing a role in communication and cognition," says Arthur Glenberg, a professor of psychology and head of the embodied cognition laboratory at ArizonaStateUniversity.
This realization has driven much of the recent work looking at how moving and thinking inform and interfere with each other. For example, a pair of studies published in 2006 by Sian Beilock, now an assistant professor of psychology at the University of Chicago, and Lauren Holt, one of her former students, examined how people who were good at certain physical activities thought about those activities.
In one study, Beilock and Holt had college hockey players, along with a non-hockey-player control group, read a sentence, sometimes hockey-related, sometimes not. Then the subjects would be shown a picture and asked if it corresponded with the sentence. Hockey players and non-hockey players alike almost invariably answered correctly, but on the hockey-related sentences the response times of the hockey players were significantly faster than the non-players. In a second study, the researchers found similar results with football players. According to Beilock, the difference in response time wasn't a matter of knowledge - after all, all of the subjects in the study got the vast majority of the questions right. What it suggested, Beilock argues, is that the athletes' greater store of appropriate physical experiences served as a sort of mental shortcut.
"People with different types of motor experiences think in different ways," she argues.
These sorts of results aren't simply limited to thinking about sports, or other highly physical activities.
A 2003 study by Michael Spivey, a psychology professor at Cornell, and his student Elizabeth Grant, found that people who were given a tricky spatial relations brainteaser exhibited a distinctive and unconscious pattern of eye movements just before they arrived at the answer. The subjects seemed to unconsciously work through the problem by enacting possible solutions with their gaze.
A study published in August by Alejandro Lleras and Laura Thomas, two psychologists at the University of Illinois, built on those results by inducing the eye movements Spivey had discovered. Lleras and Thomas found that doing so greatly improved the rate at which people solved the problem - even though most never figured out that the eye movements had anything to do with it.
"The subjects actually think that the eye-tracking task is very distracting," Lleras says. "They think we're doing this to keep them from solving the problem."
Other studies have looked at non-spatial problems and at memory. Work led by Susan Goldin-Meadow, a psychology professor at the University of Chicago, has found that children given arithmetic problems that normally would be too difficult for them are more likely to get the right answer if they're told to gesture while thinking. And studies by Helga Noice, a psychologist at ElmhurstCollege, and her husband Tony Noice, an actor and director, found that actors have an easier time remembering lines their characters utter while gesturing, or simply moving.
The body, it appears, can subtly shape people's preferences. A study led by John Cacioppo, director of the Center for Cognitive and Social Neuroscience at the University of Chicago, found that subjects (all non-Chinese speakers) shown a series of Chinese ideographs while either pushing down or pulling up on a table in front of them will say they prefer the ideographs they saw when pulling upward over the ones they saw while pushing downward. Work by Beilock and Holt found that expert typists, when shown pairs of two-letter combinations and told to pick their favorite, tend to pick the pairs that are easier to type - without being able to explain why they did so.
What's particularly interesting to neuroscientists is the role that movement seems to play even in abstract thinking. Glenberg has done multiple studies looking at the effect of arm movements on language comprehension. In Glenberg's work, subjects were asked to determine whether a string of words on a computer screen made sense. To answer they had to reach toward themselves or away from themselves to press a button.
What Glenberg has found is that subjects are quicker to answer correctly if the motion in the sentence matches the motion they must make to respond. If the sentence is, for example, "Andy delivered the pizza to you," the subject is quicker to discern the meaning of the sentence if he has to reach toward himself to respond than if he has to reach away. The results are the same if the sentence doesn't describe physical movement at all, but more metaphorical interactions, such as "Liz told you the story," or "Anne delegates the responsibilities to you."
The implication, Glenberg argues, is that "we are really understanding this language, even when it's more abstract, in terms of bodily action."
Some linguists, cognitive scientists, and philosophers go further - arguing that the roots of even the most complex and esoteric aspects of human thought lie in the body. The linguist George Lakoff, of the University of California, Berkeley, along with Rafael Nunez, a cognitive scientist at the University of California, San Diego, have for several years advanced the argument that much of mathematics, from set theory to trigonometry to the concept of infinity, derives not from immutable properties of the universe but from the evolutionary history of the human brain and body. Our number system, they argue, and our understanding of addition and subtraction emerge from the fact that we are bipedal animals that measure off distances in discrete steps.
"If we had wheels, or moved along the ground on our bellies like snakes," Lakoff argues, "math might be very different."
These ideas have met intense opposition among mathematicians, but also among some cognitive scientists, who believe they reflect an overreaching reading of a promising but still sketchy set of experimental results.
"I think these findings are really fantastic and it's clear that there's a lot of connection between mind and body," says Arthur Markman, a professor of psychology at the University of Texas. He remains skeptical, though, that the roots of higher cognition will be found in something as basic as the way we walk or move our eyes or arms.
"Any time there's a fad in science there's a tendency to say, 'It's all because of this,"' Markman says. "But the thing in psychology is that it's not all anything, otherwise we'd be done figuring it out already."
While embodied cognition remains a young field, some specialists believe that it suggests a rethinking of how we approach education. Angeline Lillard, a psychology professor at the University of Virginia, says that one possibility is to take another look at the educational approach that Italian educator Maria Montessori laid out nearly 100 years ago, theories that for decades were ignored by mainstream educators. A key to the Montessori method is the idea that children learn best in a dynamic environment full of motion and the manipulation of physical objects. In Montessori schools, children learn the alphabet by tracing sandpaper letters, they learn math using blocks and cubes, they learn grammar by acting out sentences read to them.
To Lillard, the value of embodied cognition in education is self-evident.
"Our brains evolved to help us function in a dynamic environment, to move through it and find food and escape predators," she says. "It didn't evolve to help us sit in a chair in a classroom and listen to someone and regurgitate information."
