Mindfulness & Neural Connectivity


Yoga originated as humanity’s first science of the mind, a meditative path honed through generations of Indian masters and disciples in pursuit of the ultimate: enlightenment. Several hundred years after the origin of yoga, an Indian prince not only achieved enlightenment in meditation but also shared his teachings with disciples who codified Buddhism.

Today, Western science is creating increasingly sophisticated ways of understanding the brain. We now have the capability of witnessing the inner workings of the brain through the advent of functional Magnetic Resonance Imaging (fMRI). Simply put, an immensely strong magnet reorients the magnetic components of the human body, allowing us to trace the flow of hemoglobin in blood. By watching the volume of blood flow within the cranium, neuroscientists infer which areas of the brain are demanding increased energy. In data analyses, these areas of higher blood flow look like “hot spots”, or areas that are activated by the experimental design.

The fMRI machine itself is a bit limiting in that there can be no movement: the subject must be completely still in order for the scientists to draw conclusions from the data acquired. Normal variations within subjects, like breathing, as well as between subjects, like brain size, are “normalized” as a part of data processing, which is to say there are many extrapolations before conclusions are peer-reviewed and published.

From these elucidations of neural mechanics we draw conclusions on the modern mind, which is both spurring on and coping with the sudden inundation of data that is the result of our tech-revolution. It is no wonder that yoga and Buddhism have gone mainstream and that neuroscientists are eager to bridge data-driven experimental science with ancient techniques for mental clarity.

Taren et al. published a recent (July/August 2017) study on the neural effects of mindfulness training. They chose to work with unemployed people who reported high stress levels, excluding people who already had a mind/body practice, were not looking for a job, were left handed, etc. (Handedness matters because the brains of left-handed people are wired differently.) Of the 763 people interested in the study, 50 people completed a baseline fMRI scan, and of these, 35 people participated in the training retreat. 19 subjects were randomly assigned to mindfulness training and 16 subjects to a comparable relaxation retreat. One person dropped out of the mindfulness training (the paper does not report why). 34 subjects completed a post-retreat fMRI scan that was identical to the baseline scan, and the resulting data was analyzed to determine if the brain’s connectivity patterns changed as a result of the three-day mindfulness and relaxation training programs.

It is worth taking the time to examine the meaning of mindfulness and its roots in Buddhism and yogic meditation:

Meditation is a loose translation for dhyana, which Patanjali described circa 200BC as the complete unity between self and surroundings, while dharana is complete concentration of the mind on an object or idea and yoga is defined as the cessation of mental fluctuations. Traditionally, meditation and yoga were interchangeable; the sutras contain very little information on the physical postures. Meditation was not presented with strategy or technique; instead, the focus of the sutras and the Gita is on the results of time and practice. There are no short cuts. One must simply put in the work without expecting the reward.

Yoga was created within the cultural context of ancient India, complete with devotion to the Supreme Being but without religious doctrine or rituals. When the Buddha was a young Indian prince, circa 400 BC, his education included the religious practices of Brahmins as well as traditional philosophy, medicine, and yoga. He left his royal life for that of the yogi: a wandering ascetic, living in rags and begging for rice, devoted to the spiritual over the material. His teachings became the Four Noble Truths and the Eightfold Path.

Though the Buddha did not specify mindfulness in his core teachings (the Four Noble Truths; the Eightfold path; the Dhammapada), the concept of mindfulness has become integral to modern Buddhism, where it is presented as a loose translation of sati or smriti, depending on who you are reading. The Buddha taught that the “most subtle awakening comes about through moment-to-moment attentiveness” (Prajnaparamita), which seems to be what we are calling mindfulness today.

Here are some various descriptions of mindfulness:

paying attention in a particular way, on purpose, in the present moment and nonjudgmentally (Jon Kabat-Zinn)

nonreactvity, observing/noticing, acting with awareness rather than automatically, concentration, labeling, and a nonjudgmental attitude (Daniel Siegel)

Mindfulness can exist quite well without Buddhism. Buddhism cannot live without mindfulness. (Gil Fronsdal)

If we look to yoga as the roots of Buddhism, we can see how mindfulness is one way of translating dharana while meditation is dhyana. Of the relationship between meditation and mindfulness within the context of Buddhism, Thich Nhat Hanh writes:

Meditation is a power plant for mindfulness. When we sit, eat a meal, or wash the dishes, we can learn to be mindful. Mindfulness allows us to look deeply and see what is going on. Mindfulness is the power, the hoe, and the irrigation source that waters insight.

These techniques used to be for enlightenment, for awakening—now they’re also for healing post-traumatic stress, and increasing productivity. Much has been lost in translation—but perhaps something has been gained as well. (Jay Michaelson, Evolving Dharma; 2013)

Let us adopt this attitude and explore what has been gained.

Perhaps the most mysterious part of Taren et al.’s 2017 paper was the mindfulness intervention itself. The authors write: “We adapted the standardized and manualized 8-week mindfulness-based stress reduction (MBSR) program into a condensed 3-day residential retreat format”, which was led by a “doctoral level psychologist with 7 years of MBSR teaching experience.” We are not told whether the subjects were interested in studying mindfulness, or were simply looking to earn money to help alleviate the financial stress of being unemployed. Nor do the authors speak to the effectiveness of reducing an 8-week training into 3 days.

The program itself consisted of “mindfulness training through body scan awareness exercises, sitting and walking meditations, mindful eating, and mindful movement (gentle hatha yoga postures). After each formal meditation period, participants engaged in discussion of their observations… On the third day, formal meditation practices were extended to discussions about how participants could use mindful awareness for their unemployment and job-seeking stress.” The paper does not include the degree to which the participants enjoyed or felt that they benefited from the retreat experience, nor does the paper state which hatha yoga poses were taught, or whether the subjects continued to practice these teachings post-retreat.

The control group was sent to the same retreat center for a matched three-day experience “that included similar behavior training activities (e.g., walking stretching, and didactics)”, “but all trainings emphasized participation in these activities in a relaxful way rather than a mindful way and did not include progressive muscle relaxation.” This group was instructed by “a licensed social worker with more than 2 decade of clinical experience in stress management” and authors state that this program “was designed to control for nonmindfulness specific factors, such as positive treatment expectancies, group support, teacher attention, physical activity, and mental engagement.”

The authors do not discuss the philosophical or theoretical differences between mindfulness and relaxation. Clearly mindfulness has its roots in Buddhism and perhaps even yoga, but the MBSR program strips the Buddhist principles out of the mindfulness practice, meaning that the techniques are presented secularly as mental training techniques. But is it possible to divide mindfulness from relaxation? And if not, how accurately can the relaxation group be called a control group? Body scan techniques are especially designed for physical relaxation of tension, and there is the potential that mindful eating, sitting/walking meditation, and hatha yoga all have relaxation as a primary result.

Leading a mindfulness training course in 2007, Gil Fronsdal of the Insight Meditation Center spoke to the relationship between mindful meditation and relaxation:

It’s very nice and helpful to become calm and peaceful, but in mindfulness meditation, we don’t hold that up as the great goal, to become peaceful. The goal is to pay attention. So, if you get more agitated as you meditate, which sometimes happens, remember the goal is “let me pay attention to this…”… for example, there might be something you haven’t ever looked at very carefully in your life, that you’ve been holding at a distance, and as you sit trying to relax in meditation, you lower your guard… this thing bubbles up.

The long-term benefits of meditation come from moving through these things that “bubble up”, making space in body and mind for new habits, perspectives, and appreciation for the present moment. Perhaps the relaxation control group of Taren et al.’s 2017 study was not instructed in techniques to identify and move through these difficult times, but in either case, the retreat intervention was only three days long and the follow-up fMRI session occurred within two weeks of the retreat. This is not much time for delving into deep seated mental formations but still, it is possible that the mindfulness trained participants were able to move through difficult experiences while the relaxation group simply glossed over these troublesome “bubbling” experiences. However, the authors did not report behavioral data on the retreat experiences.

Post-intervention, both the mindfulness and relaxation groups completed another resting state fMRI scan; all subjects were instructed not to sleep or engage in any meditation or relaxation behavior during the scan itself.

NB: These days, it’s highly unusual for the brain to be both awake and at rest without internet stimulation, but this is the condition of the resting state fMRI paradigm: the subject is laying on her back, immobilized, head cushioned to stare at a gray screen with a small black crosshair, instructed not to move, relax, or meditate. It is both extremely boring and claustrophobic, which is to say, perfect conditions for testing mindfulness. However, the authors specifically instructed participants to not meditate or relax, and each participant verbally confirmed that they did not meditate or use relaxation techniques during the resting state scan.

Taren et al confirmed their hypothesis that mindfulness meditation training would increase resting state functional connectivity between executive control regions. In other words, they predicted and concluded that mindfulness training will rewire the brain even when it is at rest, not attending to stimuli or tasks. 

The authors used standard functional connectivity data analyses. Beginning with a “seed region” of interest, they ran codes that searched the brain for links between the seed region and all other areas of the brain. The analyses specifically searched for changes that were different from baseline to post-intervention for the meditation group versus the control, relaxation group. (This is called time by group difference.)

The resulting data analysis supported the author’s hypothesis: the meditation group had increased functional connectivity between the left dorsolateral prefrontal cortex (dlPFC; which is located just behind the left side of your forehead) and the other regions of the executive control network: right inferior frontal gyrus, right suplamental eye field, right middle frontal gyrus, left superior parietal lobule, and left middle temporal/angular gyrus. The right dlPFC showed increased connectivity to the right middle frontal gyrus. The authors concluded that “this pattern for mindfulness-associated increased rsFC supports the idea that mindfulness may modulate task-independent functional connectivity between executive and attentional brain regions.”

The authors do not address why the dlPFC have greater connectivity to attention network, considering that participants were instructed not to make decisions or pay attention to the present moment. Why would a retreat, mindfulness or otherwise, change the attention network at rest? Are mindful people paying attention even when they state that they are not practicing mindfulness? It would have been interesting to see the results of a scan in which all participants were instructed to pay attention to the moment, in both baseline and post-intervention scans, to see if executive control was strengthened by training.

The reported experimental design is logical if considered from the perspective of trauma research: it hinges on the concept that a one time event (in this case, a retreat) will rewire neural connectivity. But long-time practitioners of yoga, Buddhism, and artistic disciplines know that the true effects of the practice come from steady, sustained effort over days, months, years, decades. With this in mind, Taren et al. could have designed their study differently, instructing their participants to “relax” or “focus” during both the baseline and post-intervention fMRI sessions. Then it would be possible to run two separate between-group data analyses: one, which they already did, dividing the mindfulness group from the relaxation group, but also another, dividing the subjects who independently practiced their teachings from those who returned to their pre-intervention habits. This second data analysis, which would take very little time and require no additional funding, would reveal whether it was the nature of the intervention that mattered or the practice itself. It is likely that practicing walking and stretching for relaxation would be just as beneficial as practicing walking and asana for mindfulness, which is also to say that mindfulness training has little value unless applied to daily life.

Had the authors used “practice” as an experimental variable in data analyses, this study could have spoken to whether the format of training (mindfulness or relaxation) matters as much as duration and/or intensity of practice. Another interesting question is the length of time that passed between each participant’s retreat experience and post-retreat fMRI scan. For each person, it was within two weeks, but the time period was not specifically stated as a variable. If subjects did not practice, then the time period between retreat and scan could have been used to determine how long it takes for a 3-day retreat to “wear off”, presuming that the retreat was effective in reducing stress in the first place (which the authors did not speak to in this paper). It is possible that each individual has varying degrees of “habit energy” that would draw them back into their stressful daily lives as they search for employment, and that the condensed 3-day retreat did not provide long term benefits. It would have also been interesting to note whether or not the participants, who spent three days together in group practice and discussion, kept in touch with one another post-experiment. In Buddhism, the sangha, or community, is a foundation of the practice, which is also a benefit of joining group exercise classes that focus on fitness and relaxation. But as is typical in neuroscience papers, very little behavioral data was reported.


As a yogi scientist, I wonder: how do we apply our explorations of the brain with our experience of the mind? And will cover more cognitive neuroscience in the coming weeks!