Dr Catherine Kerr

Don’t believe the hype

wildmind meditation newsLinda Heuman, Tricycle: Neuroscientist Catherine Kerr is concerned about how mindfulness meditation research is being portrayed in the media.

Last May, an article about mindfulness on a popular mainstream news website finally spurred neuroscientist and meditation researcher Catherine Kerr to act. The article cited 20 benefits of meditation, from “reducing loneliness” to “increasing grey matter” to “helping sleep,” and painted a picture of meditation as a kind of golden elixir for modern life. Kerr posted the article on her Facebook page. “It is not like any of this is grossly inaccurate,” she wrote in her post. “It is just that the studies are too …

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Catherine Kerr on the Science of Meditation

Alex Knapp, Forbes: Dr. Kerr received her BA in American Studies from Amherst College and her PhD in History and Social Theory from the Johns Hopkins University, but in 2006 received a K Award from the National Institutes of Health to be retrained as a neuroscientist. Since then, her research primarily focused on the effects of meditation the brain.

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Recently, I wrote up a paper that had some interesting results regarding the mechanisms through which the practice of meditation might lead to pain relief. Namely, the results suggested that meditation can lead to changes in alpha wave behavior, which in turn may lead to the pain relief through the inhibition communication in the brain. Since that time, I’ve had a chance to communicate with Catherine Kerr, formerly the Lab Director at the Neuroscience of Meditation, Healing and Sense of Touch Lab at the Osher Research Center at Harvard, and who is now associated with Brown University. Dr. Kerr received her BA in American Studies from Amherst College and her PhD in History and Social Theory from the Johns Hopkins University, but in 2006 received a K Award from the National Institutes of Health to be retrained as a neuroscientist. Since then, her research primarily focused on the effects of meditation the brain.

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Tell me about your background. What got you interested in studying meditation?

The route that I took on the way towards my study looking at the effects of meditation training on alpha rhythms in somatosensory cortex has been circuitous.

My interest arose out of my early work on the placebo effect in chronic pain. It’s sort of a long story that has to do with a specific theoretical interest that I developed. It began in 2001 with my earliest research, in which I investigated placebo effects, working closely with Ted Kaptchuk at Harvard Medical School. I helped Ted design and implement several large cutting-edge clinical trials that investigated placebo effects (published in BMJ in 2006 and 2008).

What we learned from these studies was that healing is more likely to come about when there is a tactile or somatic “body-based” placebo (like a tactile-sham needle) administered by a warm, confident practitioner. What these placebo studies suggested to me was that there might be a common factor – something like body-based attention — that was being manipulated by confident healers in many different modalities such as acupuncture, light touch massage and other ritual treatments.

Interestingly, body based attention to touch sensations, and more generally the sense of touch, are disordered in chronic pain and IBS. And the disorder seems to be mediated by a cortical mechanism. So, what I intuited from my work on placebo was that many therapies may elicit healing by using the sense of touch, or more generally the manipulation of somatic attention in order to address a disordered somatic-attention system. One way of thinking about somatic attention is to think of it as a biasing system – in chronic pain patients, attention becomes biased towards the chronic pain percept so that the sensation intrudes on and interferes with everyday life. What acupuncture and other therapies may actually do is to help erase or undo some of these biases so that the sensation, while it might not disappear, is less intrusive and has less of an effect on daily activities.

How did you develop your brain-based approach to meditation?

Although my initial intuition about body-based attention and healing was interesting and promising, it was not framed as a scientific question at the level of brain mechanism. To reframe this idea as a testable brain science question, I was very lucky to work with an incredibly creative, brilliant brain scientist named Christopher Moore at MIT’s McGovern Institute. It turned out Chris had formed some of the same ideas, especially based on his experiences with acupuncture and light-touch massage, except that unlike me, Chris is (1) a sophisticated thinker about the brain and (2) a brilliant experimentalist who is deeply knowledgable about the somatosensory system in animals and humans.

Chris Moore, working with his colleague Steph Jones at Massachusetts General Hospital, helped me reframe my interest in the somatosensory attentional system as a problem in brain dynamics and brain rhythms: how does the brain constantly adjust its “biases” (ie, the likelihood of neurons to fire) in response to new situations? And, how might somatic-attention focused therapies help the brain respond more adaptively to new situations and shed pre-existing, maladaptive biases like those seen in chronic pain?

It turns out that alpha rhythms in the cortex may serve as a useful index for understanding how attentional biases are maintained—many studies have shown that alpha rhythms can be controlled in a precise “map-like” way by attention. That is, alpha rhythms can help to suppress or amplify sensory inputs in a specific location, for example, in your visual field when I cue you about a location where a stimulus is likely to appear.

What aspects of meditation has your research focused on and why did you choose that focus?

We chose mindfulness meditation because, it turns out that mindfulness meditation is not the same as napping or relaxing: instead, the practice actually involves a very strong attentional focus on the breath and body sensations—the cultivation of somatically focused attention is the critical factor for training the attentional system in the earty stages of practice. This is even spelled out in an early Buddhist sutra (which talks about “mindfulness of the body”) although I did not know this when we assembled our hypotheses.

In our brain experiment, we actually looked at what happens in the “body map” in the somatosensory cortex when you are asked to pay attention to your hand versus when you are asked to pay attention to your foot. We tested the effects of a specific, standardized form of mindfulness meditation called mindfulness based stress reduction. Our hypothesis was that after meditation training, meditators would have more attentional control over their brain rhythms in the brain’s map of the hand—meditators would be able to adjust their alpha rhythms more precisely depending on whether they were attending towards or away from the finger. Our hypothesis was proven correct as meditators demonstrated a higher ability to control their brain rhythms than nonmeditators and they were faster (after a cue) in exerting this control.

It’s important to mention that our study had a small sample size (given this size, it’s surprising how strong the statistical significance of the effect was), so this study should be viewed as a “proof of principle” that needs to be replicated in a larger study.

What about meditation research has surprised you the most?

Two things have surprised me and I think they are a little bit related.

First, I was surprised by my experience of the actual practice of mindfulness meditation. My experience came about because I felt that it was important, as a scientist, to actually undergo the same type of training as my subjects.

So after all of my subjects were done with the course, out of curiosity, I actually enrolled in the same 8-week standardized mindfulness course and, on a subjective level, I found it to be very transforming—this surprised me. The course involved daily sitting meditation practice, the core of which involved an attentional focus on the breath and body-related sensations for 20-30 mins per day. This attentional focus was more difficult than I thought it would be. The difficulty wasn’t so much in the beginning. Rather, it was about half way through the 8-week class, I found that the meditation practice actually brought up some charged unresolved emotions from different past experiences. What I found was that, at first these unresolved emotions were difficult but as I continued in the course, they actually became much more easy to deal with – and in general, I just felt more at ease, even in difficult or stressful situations.

But my experience was so complex: were these effects captureable through the brain imaging paradigm that I designed? Having more control over the cortical dynamics of attention should lead to having more ability to regulate cognition, including cognitions related to emotionally charged issues. But, of course, I did not directly test this question.

One reason I tell this story is to emphasize there is always going to be a gap between the subjective effects that people report experiencing during meditation and the putative objective brain mechanisms that are put forth to explain the effects. Skeptics deal with this gap by simply dismissing the subjective experience as “woo.” I understand why they do this – but I think this dismissal is actually quite unscientific since one of the things that’s so fascinating about a practice like mindfulness meditation is the fact that it seems to reliably induce these complex, transformational subjective experiences. In their exit interviews, my subjects spontaneously offered different accounts of personal transformation). Isn’t that interesting?

Of course, the flip-side of this impulse to reject subjective experience that you see in the skeptic community can be seen in meditation enthusiasts and their uncritical embrace of neuroscience—this embrace has been my second surprise.

There has been a kind of mania or madness surrounding the brain and meditation that I see most strongly in studies reporting on brain plasticity. Take the wonderful work (on which I am a coauthor), led by Sara Lazar at MGH, on structural changes in the brain that are correlated with meditative practice. This research is fascinating and very promising but it is also fraught with uncertainty.

When we see differences between experienced meditators and controls on structural MRI images we don’t actually know what is causing that difference. It could be changes in vasculature or in dendritic arborisation. And these differences matter a lot as we consider how structural changes might relate to any possible changes in how the brain processes information. For instance, since these brain changes are not correlated with any measure of function, we don’t know if the reported changes in brain structure are a good thing, since there can be pathological increases in brain structure which have been observed in some diseases!

Yet people take this idea that “meditation grows your brain” (which we never claimed in our early report and which Sara Lazar still approaches cautiously although she has published new data on this question) and run with it, to the point of absurdity—the idea that meditation might change brain structure appears to exert some kind of magnetic power (for an example of this, check out the coverage of Sara Lazar’s recent study in Gawker or a recent Huffpo piece that I flagged on Twitter). Some of the ways in which our 2005 study have been summarized point to a shocking lack of scientific literacy about brain imaging and a poor understanding of what a correlational brain study in experienced meditators can actually tell us.

Stepping back a little bit to meditation in general, it seems to attract a lot of pseudoscience to it. How much do we really know about meditation right now, and what needs to be studied?

I think my two surprises are related to one central problem: because subjective experiences like those felt in meditation practice can be very powerful, there is a strong impulse to try to capture or “bottle” these experiences in a brain image. While I think brain imaging will be and has already been very informative about these practices, it’s important to understand that (1) brain imaging cannot do away with the basic gap between subjective experience and objective measurement (2) complex subjective experiences like those felt in meditation are likely made up of a complex array of brain mechanisms that cannot be captured by the simple sets of hypotheses that can be tested in a single brain experiment.

That being said, I do think that we can draw some conclusions about how mindfulness meditation practice might affect brain processes related to attention and emotion regulation. Work by our group on attention regulation and somatosensory brain dynamics comes in addition to fine work by Amishi Jha showing that mindfulness meditation appears to exert specific effects on well-defined attentional dynamics related to basic sensory processes. Work by Philipe Goldin and coauthors suggests that mindfulness practice may exert effects on the reactivity of the amygdala to emotional challenge. And, work by Sara Lazar and others (including her subsequent study) in replication of her brave initial effort, suggest meditation causes changes in brain structure. I think the most important idea underlying all of these studies, that is now well-established is that the standardized form 8-week format of mindfulness meditation training called MBSR that we and others have studied (which is reported to reduce distress in many patient groups) involves an active process of attentional training and is not the same as relaxing or napping. Although some skeptics might wish this was not true.

What kinds of claims about meditation do you see in your work that don’t seem to be backed by science?

My experience with media coverage of my alpha meditation study has been a little different from that which I observed in coverage of the Lazar meditation-brain-structure study. The mechanism and the paradigm used to test the mechanism are both complex. While the implications of my study are far-reaching (especially the notion that meditators exert more precise attentional control over the “volume knobs” in sensory neurons in the brain) , many media outlets have had trouble understanding really basic aspects of the experiment (what we tested, who were our subjects, etc). There is not much I can do about this.

As a scientist, how do you respond to people who use your research to bolster non-scientific claims?

I don’t respond since response would involve me in endless distraction and since I know that whoever has misunderstood my study has probably been triggered by the current brain-meditation mania rather than the specific details of my own work.

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Meditation may help the brain ‘turn down the volume’ on distractions

The positive effects of mindfulness meditation on pain and working memory may result from an improved ability to regulate a crucial brain wave called the alpha rhythm, say researchers from Massachusetts General Hospital (MGH), Harvard Medical School and the Massachusetts Institute of Technology. This rhythm is thought to “turn down the volume” on distracting information, which suggests that a key value of meditation may be helping the brain deal with an often-overstimulating world.

The researchers report that modulation of the alpha rhythm in response to attention-directing cues was faster and significantly more enhanced among study participants who completed an eight-week mindfulness meditation program than in a control group. The report will appear in the journal Brain Research Bulletin and has been released online.

“Mindfulness meditation has been reported to enhance numerous mental abilities, including rapid memory recall,” says Catherine Kerr, PhD, of the Martinos Center for Biomedical Imaging at MGH and the Osher Research Center at Harvard Medical School, co-lead author of the report. “Our discovery that mindfulness meditators more quickly adjusted the brain wave that screens out distraction could explain their superior ability to rapidly remember and incorporate new facts.”

Brain cells use particular frequencies or waves to regulate the flow of information in much the same way that radio stations broadcast at specific frequencies. One frequency, the alpha rhythm, is particularly active in the cells that process touch, sight and sound in the brain’s outmost layer, called the cortex, where it helps to suppress irrelevant or distracting sensations and regulate the flow of sensory information between brain regions.

Previous studies have suggested that attention can be used to regulate the alpha rhythm and, in turn, sensory perception. When an individual anticipates a touch, sight or sound, the focusing of attention toward the expected stimulus induces a lower alpha wave height in cortical cells that would handle the expected sensation, which actually “turns up the volume” of those cells. At the same time the height of the alpha wave in cells that would handle irrelevant or distracting information increases, turning the volume in those regions down. Because mindfulness meditation – in which practitioners direct nonjudgmental attention to their sensations, feelings and state of mind – has been associated with improved performance on attention-based tasks, the research team decided to investigate whether individuals trained in the practice also exhibited enhanced regulation of the timing and intensity of alpha rhythms.

The study tested 12 healthy volunteers with no previous experience in meditation. Half completed the eight-week Mindfulness-Based Stress Reduction Program developed at the University of Massachusetts. The other half were asked not to engage in any type of meditation during the study period. Using magnetoencephalography (MEG), an imaging technique that detects the location of brain activity with extreme precision, the researchers measured participants’ alpha rhythms before, during and after the eight-week period. Specifically, they measured alpha rhythms in the brain area that processes signals from the left hand while participants were asked to direct their attention to either their left hand or left foot. Participants’ abilities to adjust the alpha rhythm in cortical cells associated with the hand, depending on where their attention was directed, were recorded during the milliseconds immediately after they received an attention cue.

Although all participants had showed some attention-related alpha rhythm changes at the beginning of the study, at the end of the eight weeks, those who completed the mindfulness meditation training made faster and significantly more pronounced attention-based adjustments to the alpha rhythm than the non-meditators did. “This result may explain reports that mindfulness meditation decreases pain perception,” says Kerr. “Enhanced ability to turn the alpha rhythm up or down could give practitioners’ greater ability to regulate pain sensation.”

The study also sheds light on how meditation may affect basic brain function, explains Stephanie Jones, PhD, of the Martinos Center, co-lead author of the paper. “Given what we know about how alpha waves arise from electrical currents in sensory cortical cells, these data suggest that mindfulness meditation practitioners can use the mind to enhance regulation of currents in targeted cortical cells. The implications extend far beyond meditation and give us clues about possible ways to help people better regulate a brain rhythm that is dysregulated in attention-deficit hyperactivity disorder and other conditions.” Kerr is an instructor in Medicine and Jones an instructor in Pediatrics at Harvard Medical School (HMS).

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