Millions of people around the world seek mental clarity through meditation, most of them following or inspired by the centuries-old practices of Buddhism.
Anecdotally, those who meditate say it helps to calm their minds, recenter their thoughts and cut through the “noise” to show what really matters. Scientifically, though, showing the effects of meditation on the human brain have proved to be tricky.
A new study from Binghamton University’s Thomas J. Watson College of Engineering and Applied Science tracked how practicing meditation for just a couple of months changed the brain patterns of 10 students in the University’s Scholars Program.
The seed for the research came from a casual chat between Assistant Professor Weiying Dai and lecturer George Weinschenk, MA ’01, Ph.D. ’07, both from the Department of Computer Science.
Weinschenk is a longtime meditation practitioner whose wife worked as an administrator at the Namgyal Monastery in Ithaca, which is the North American seat of the Dalai Lama’s personal monastery.
“I developed very close friendships with several of the monks,” he said. “We would hang out together, and I even received instruction from some of the Dalai Lama’s teachers. I took classes there, I read a lot and I earned a three-year certificate in Buddhist studies.”
Dai has studied brain mapping and biomedical image processing, and while earning her Ph.D. at the University of Pittsburgh, she tracked Alzheimer’s disease patients using magnetic resonance imaging (MRI) scans.
“I’m interested in brain research to see how our brains are really functioning and how all different kinds of disease affect our brain,” she said. “I really have zero medical training, but I pick up all this knowledge or background from reading the literature and talking with the experts.”
The two faculty members had neighboring offices and shared a conversation one day about their backgrounds. Weinschenk mentioned that he had been asked to teach a semester-long class for the Scholars Program on meditation.
“I told Weiying, ‘Yeah, meditation really can have a transformative effect on the brain,’” Weinschenk said. “She was a little skeptical, especially about whether such a short amount of time spent learning how to meditate, whether that would make any difference. She suggested we might be able to quantify such a thing with modern technology.”
For the fall 2017 semester, Dai secured grant funding, and their collaboration began. Near the beginning of the semester, she took the participants to Cornell University for MRI scans of their brains. Weinschenk taught students how to meditate, told them to practice five times a week for 10 or 15 minutes, and asked them to keep a journal record of their practice. (The syllabus also included other lessons about the cultural transmissions of meditation and its applications for wellness.)
“Binghamton University Scholars are high achievers who want to do the things they are assigned and do well on them, so they didn’t require much prompting to maintain a regular meditation routine,” he said. “To guarantee objective reporting, they would relate their experiences directly to Weiying about how frequently they practiced.”
The results, recently published in the journal Scientific Reports, show that meditation training led to faster switching between the brain’s two general states of consciousness.
One is called the default mode network, which is active when the brain is at wakeful rest and not focused on the outside world, such as during daydreaming and mind-wandering. The other is the dorsal attention network, which engages for attention-demanding tasks.
The findings of the study demonstrate that meditation can enhance the brain connection among and within these two brain networks, indicating the effect of meditation on fast switching between the mind wandering and focusing its attention as well as maintaining attention once in the attentive state.
“Tibetans have a term for that ease of switching between states – they call it mental pliancy, an ability that allows you to shape and mold your mind,” Weinschenk said. “They also consider the goal of concentration one of the fundamental principles of self-growth.”
Dai and Weinschenk are still parsing through the data taken from the 2017 MRI scans, so they have yet to test other Scholars Program students. Because Alzheimer’s disease and autism could be caused by problems with the dorsal attention network, Dai is making plans for future research that could use meditation to mitigate those problems.
“I’m thinking about an elderly study, because this population was young students,” she said. “I want to get a healthy elderly group, and then another group with early Alzheimer’s disease or mild cognitive impairment. I want to see whether the changes in the brain from meditation can enhance cognitive performance. I’m writing the proposal and trying to attract the funds in that direction.”
Though once skeptical about the subject, “I’m pretty convinced about the scientific basis of meditation after doing this study,” she added. “Maybe I’ll just go to George’s class when he teaches it so that I can benefit, too!”
The Practice of meditation has been associated with altered neural activity and reorganization (see a review1). Most examinations are task related, especially those that include meditation or engage trained skills, and are susceptible to expectancy and knowledge-based biases that can change neural signals.
Brain activations observed during meditation provide evidence for increases of neural activity while practicing meditation; however, the findings may have been influenced by the individual variance of performing the required meditation during the fMRI scanning.
Only when the state of neural activity has increased through repeated meditation practice, when meditation is not being practiced such as during rest, and has become a trait of the brain, will it provide a neural basis for enhanced attentional control and emotional regulation that can translate to daily life.
To address how meditation training alters trait-level neural reorganization, we conducted a longitudinal examination of how 8 weeks of Focused Attention Meditation (FAM) training alters task-independent resting-state functional connectivity using multi-echo functional magnetic resonance imaging.
Meditation comes in many forms, such as focused attention or open monitoring or non-dual awareness. Here we examined FAM training, which involves reorienting attention onto an internal or external object and inhibiting distraction of mind wandering or random thoughts.
Mind wandering and reorienting attention were associated with neural activity in the default mode network (DMN)2–6 and dorsal attention network (DAN)/ventral attention network (VAN)7–10, respectively.
FAM has been reported with generally increased task-related neural activation in brain regions that have been reported involved in brain attention processing11–14, although they are not completely consistent. Experienced meditators exhibited increased activation during meditation in the anterior cingulate and medial prefrontal cortex (prefrontal regions in DMN) compared to controls11.
Long-term meditators showed significantly more activation in the majority of attention regions of interest (a priori DAN regions from a meta-analysis involving attention-shift paradigms) than novice meditators during meditation12.
This study also reported that long-term meditators had more activation in the left superior frontal gyrus and middle frontal gyrus (prefrontal regions in DMN) when compared to incentive novice meditators (to remove the potential motivational difference of the long-term meditators).
Similar findings extend to individuals randomized to an 8-week course in mindfulness meditation training, which was associated with decreased cortical midline recruitment associated with internal self-referential process (DMN areas)13 and increased activity in brain regions implicated in external visual attention, including inferior and superior parietal lobes (DAN areas) and middle occipital gyrus (Visual Cortex)14.
Structural magnetic resonance imaging (sMRI) has associated FAM with trait changes of the brain structure. A number of sMRI studies found increased gray matter density15–17 and cortical thickness18–21 in brain regions involving self-referential and attention processing, such as superior parietal gyri (posterior regions in DAN), precuneus (a posterior region in DMN), anterior cingulate, superior and middle frontal gyri, and orbitofrontal (prefrontal regions in DMN) regions in meditators.
Longitudinal sMRI studies demonstrated the increases in gray matter density after an 8-week meditation training, which provide more direct evidence of the effects of meditation on brain structural changes in posterior cingulate cortex and temporoparietal junction (posterior regions in DMN)20,22,23. One of the longitudinal sMRI studies found that reductions in perceived stress were correlated with changes in gray matter density, demonstrating that neuroplastic changes induced by meditation are associated with improvements in mental states.
Brain resting-state functional connectivity (rsFC) can provide the trait measure for coherent neural activity between different regions of the brain during the resting state. Therefore, rsFC can provide a less biased account of neural network changes with meditation practice compared to task-based fMRI. Meditation studies in functional connectivity have conducted cross-sectional studies to compare the rsFC between meditators and controls24–26 and the meditation-state functional connectivity (msFC) between meditators and controls26,27.
Other studies compared the same subjects at different conditions: rsFC and msFC in experienced meditators24,28. These cross-sectional resting-state and state-related meditation studies generally involved the changes of functional connectivity in two brain networks: the DMN and DAN, although the directions of changes may not agree well.
Longitudinal studies have been performed but mainly focused on the potential benefits of meditation on specific medical groups, such as cognition of the elderly29, anxiety of the stressed community30, and symptoms of posttraumatic stress disorder (PTSD) subjects31. Therefore, the causal effect of meditation on the trait rsFC measure of novice meditators has not been systematically studied.
Consistent with the FAM training process and meditation results from morphological18–23 and resting-state rsFC24–26 changes, our first hypothesis was that FAM would result in stronger connection within the DAN and/or between the DAN and the visual cortex, for maintaining attentive status over a long period of time.
In addition, there would be a stronger connection between DMN and DAN/visual cortex for switching between mind wandering and focused attention. We further hypothesized that rsFC would vary among participants according to the practice time of meditation.
While amount of adherence to a meditation practice may reflect an expectancy bias during a task or meditative state during scanning, changes in task-free resting connectivity are less susceptible to these biases and would better reflect baseline changes in brain dynamics associated with and potentially caused by greater practice. We tested the hypotheses by using a longitudinal study design and multi-echo (ME) BOLD fMRI to assess the changes in brain rsFC after practicing FAM over a 2-month period.
ME BOLD fMRI, instead of frequently used single-echo BOLD fMRI, has been adopted in the study because of its effectiveness in mitigating imaging artifacts due to subject motion and various sources on physiological noises and thereby increasing SNR32,33.
This noise is particularly relevant to the meditation studies as there are often peripheral physiological changes in respiration and heart rate and their variability with meditation practice34, which can differentially influence detection of BOLD signal and estimates of functional connectivity at baseline and the 2-month follow-up. We expect that the ME fMRI technique will largely increase the reliability of our longitudinal mediation results.
reference link : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8166909/
Original Research: Open access.
“Longitudinal effects of meditation on brain resting-state functional connectivity” by Zhang, Z. et al. Scientific Report