As a radiologist and mindfulness practitioner, I’ve become fascinated by the ways in which mindfulness creates changes in the brain. When I started practicing mindfulness 25 years ago, I noticed increased focus and decreased stress, but I didn’t understand the underlying reasons for these effects. Several years ago, I decided to learn more and go through a mindfulness instructor course. I started looking more into the mechanisms of mindfulness and I was interested to discover that researchers have found, using MRI, that when people practice mindfulness regularly there are physical changes in the brain.
One of the first studies to use MRI to examine the brains of mindfulness practitioners was performed by Sarah Lazar and her colleagues. They used MRI to compare cortical thickness of experienced meditators, who practiced Buddhist Insight meditation, a form of meditation that practices focused attention rather than mantras, and non-meditators. The study found that the meditators had greater gray matter thickness in the insula, which is involved in bodily attention and right Brodmann areas 9/10, which are involved in the integration of cognition and emotion. The study also found that these changes were more pronounced with increasing years of practice, which suggests that mindfulness practice can counteract age related cortical thinning.
The study by Lazar and colleagues showed differences in brain structure between mindfulness practitioners and non-mindfulness practitioners. Hölzel and colleagues investigated whether or not they could see changes in the brain as non-mindfulness practitioners began a mindfulness practice. The study employed MRI to examine 17 individuals who participated in a six week Mindfulness Based Stress Reduction (MBSR) Course.
After completing the MBSR course, MRI scans showed increased gray matter concentration in the hippocampus, posterior cingulate cortex, temporo-parietal junction and cerebellum extending into the brainstem. The hippocampus affects how the cortex is activated and responds and has a role in emotional regulation. The temporo-parietal junction is involved in the conscious experience of the body. It also is involved in understanding others’ state of mind, contributing to compassion. The posterior cingulate cortex is involved in evaluating whether a stimulus is relevant to the self, particularly with reference to one’s emotions and past experience.
The posterior cingulate cortex, temporo-parietal junction and hippocampus are part of a brain network. This network works to remember the past, think about the future and consider the viewpoint of another person. It is proposed that mindfulness training creates a shift in perception by making it easier to consider the point of view of another person.
The areas of the cerebellum that showed change are involved in emotion and cognition, by regulating the speed and appropriateness of responses. The areas of the brainstem that showed change included the raphe nucleus and the locus coeruleus. The raphe nucleus is involved in serotonin release and plays a role in mood. The locus coeruleus synthesizes and releases norepinephrine and affects arousal and attention. Dysfunction in these areas can create problems with sleep, anxiety and mood. Mindfulness training may help prevent these problems.
Tang and colleagues took a group of 45 undergraduates who had never practiced mindfulness and taught them a form of mindfulness called Integrative Body-Mind Training (IBMT). The participants practiced IBMT 30 minutes per day, for a total of 11 hours over the course of a month. Controls practiced a relaxation technique for the same amount of time. Participants were then scanned with MRI to examine the fractional anisotropy of the white matter in the corpus callosum and corona radiata. Fractional anisotropy measures the degree to which water molecules move freely. In white matter tracts, water more easily moves along the tracts rather than across them.
Participants who had practiced IBMT for 11 hours showed increases in fractional anisotropy in the left anterior corona radiata, the body and genu of the corpus callosum, superior corona radiata and superior longitudinal fasciculus. Participants who practiced relaxation for 11 hours showed no changes in fractional anisotropy. The increases in fractional anisotropy in IBMT practitioners may be due to increased myelination or more organized white matter tracts. The authors of the study interpreted the increase in fractional anisotropy as indicative of improved connectivity in the anterior cingulate cortex to other brain parts, potentially enhancing self-regulation.
These studies show that there is a correlation between mindfulness practice and physical changes in both gray and white matter in areas involved with attention, cognition, emotional regulation and mood. They establish a scientific basis for the benefits of mindfulness practice with even small amounts of daily practice. They also suggest that these effects are dose-dependent, with greater effects seen with long term practice.
References
Hölzel, B. K., Carmody, J., Vangel, M., Congleton, C., Yerramsetti, S. M., Gard, T., & Lazar, S. W. (2011). Mindfulness practice leads to increases in regional brain gray matter density. Psychiatry research, 191(1), 36–43. https://doi.org/10.1016/j.pscychresns.2010.08.006
Lazar, S. W., Kerr, C. E., Wasserman, R. H., Gray, J. R., Greve, D. N., Treadway, M. T., McGarvey, M., Quinn, B. T., Dusek, J. A., Benson, H., Rauch, S. L., Moore, C. I., & Fischl, B. (2005). Meditation experience is associated with increased cortical thickness. Neuroreport, 16(17), 1893–1897. https://doi.org/10.1097/01.wnr.0000186598.66243.19
Tang, Y. Y., Lu, Q., Geng, X., Stein, E. A., Yang, Y., & Posner, M. I. (2010). Short-term meditation induces white matter changes in the anterior cingulate. Proceedings of the National Academy of Sciences of the United States of America, 107(35), 15649–15652. https://doi.org/10.1073/pnas.1011043107
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