This finding confirms the neuroplastic effect seen in other studies (which have shown how aerobic exercise and meditation produce an increase in hippocampus volume). If meditation and physical activity are commonly thought to stimulate brain regions associated with age-related neurodegeneration, as does yoga, should we accept yoga as a similar complimentary treatment intervention? If we decide to look deeper into the neural systems associated with physical activity, meditation, and yoga, we may find that they are not so similar after all.
Contrary to common belief, meditation and physical activity are associated with unique and contrasting structural differences in neural regions that do not quite overlap. A variety of studies shows that meditators were repeatedly shown to have greater hippocampal, insular volume, and left inferior temporal gyrus volume than controls. Greater cardiorespiratory fitness and physical activity were most consistently associated with larger hippocampal and prefrontal gray-matter volume. Given that yoga is a meditative practice embodied in physical postures, it may be likely that there are specific brain regions whose gray matter is more likely influenced by either postures, breath control, meditation, or a combination of these. A study that investigated such a conjecture was published in Frontiers in Human Neuroscience.
In this study, Chantal Villemure, along with others, used functional MRI data from 14 experienced yoga practitioners and 14 physically active age-matched controls to investigate age-related gray-matter decline and the effect of increasing yoga experience and weekly practice on gray-matter volume. They also assessed which aspects of the weekly practice contributed most to brain size.
To their astonishment, the researchers found that the physically active age-matched controls displayed typical age-related reduction in gray-matter volume while the yogis did not. They also found that regular weekly yoga practice is associated with larger brain volume in areas involved in somatic representation, attention, self-relevant processing, visualization, and stress regulation. In particular, the number of years of yoga experience was positively correlated with gray-matter volume in clusters located in the left mid-insula, and left frontal operculum. The weekly amount of yoga practice was positively correlated with gray-matter volume in clusters located in the right primary somatosensory cortex, left hippocampus, and right primary visual cortex.
Furthermore, the three distinct subcomponents of the weekly yoga practice — which included postures, breathing exercises, and meditation — significantly predicted unique gray-matter volumes in particular areas of the brain that are associated with the processing of these three techniques. Yet one of the most fascinating findings of this study is that certain brain regions for the yoga practitioners located in the left hemisphere (insula, frontal operculum, and orbitofrontal cortex) continued to grow after several years of practice, suggesting that increasing practice tunes the brain toward a parasympathetically driven mode associated with relaxation, peace, and healing.
Since yoga can progressively grow and rewire certain regions of the brain that are prone to degeneration, it should be administered during the early signs of mild cognitive impairment and subjective cognitive impairment, both risk factors for developing Alzheimer’s disease. Dr. Dharma Singh Khalsa, of the Alzheimer’s Research and Prevention Foundation in Tucson, Arizona, conducted a series of three studies investigating the positive effects on memory in subjects with both mild and subjective cognitive impairment who took part in a simple 12-minute yoga meditation called Kirtan Kriya.
For the first study, 14 subjects received single-photon emission computed tomography (a nuclear medicine tomographic imaging technique) and comprehensive memory testing before and after eight weeks of Kirtan Kriya practice. The second study added outcomes of common risk factors for Alzheimer’s disease, such as perceived stress, mood, sleep, blood pressure, and memory. The third study measured memory function, mental health, and cellular health in highly stressed dementia caregivers.
When compared to controls, the meditation group showed a significant increase in baseline cerebral blood flow in important brain areas related to Alzheimer’s disease, enhanced scores on memory tests, and improvement in mood and anxiety. Compared to controls, participants in Kirtan Kriya also demonstrated improvement in all major outcomes including perceived stress, mood, depression, sleep, blood pressure, and memory. This group had less depression, higher levels of well-being, and an astounding increase of 43 percent in cellular health (the largest increase ever recorded) along with a decrease in inflammatory markers.
Because chronic stress, memory loss, and cognitive impairment are being increasingly associated with the onset of Alzheimer’s disease, perhaps it is now time to administer yoga interventions as significant preventive treatment measures.
I can’t help but think of my grandmother, whom I call Nana, an 88-year-old woman suffering from the last stages of Alzheimer’s in a nursing home in Illinois. I could remember when our conversations would last for hours, discussing Miles Davis, fine wines, Picasso, and how she cooks a pizza. I also remember her stress and anxiety — something she would try to channel through her cooking and love of painting.
But soon it all caught up with her and she started forgetting and not knowing why. None of us did. The doctors put her on a combination of antidepressants and tranquilizers and told her to relax, even when her husband, my grandfather Leo, passed away. Sometimes I think that if the signs of cognitive distress and impairment were caught earlier and that if she took part in a practice that integrated mind and body and nurtured those neurological systems that needed tending instead of buffering, she would still be able to call me on the phone and discuss Picasso a few more times.
This article was first published in Brain World Magazine’s Winter 2017 issue.
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