How does the physical practice of yoga, compared with meditation, affect your brain? In a recent fMRI study, researchers observed greater resting state functional connectivity (i.e., an index of brain connectivity captured when one is not actively performing a task) in similar brain regions among Kripalu yoga and meditation practitioners when compared to non-practitioners. Dr. Tim Gard and colleagues hypothesize that the findings may help to explain the improved mental health and well-being commonly seen among those who practice yoga and meditation (findings were similar in both groups).
Reflecting our cultural brain obsession, the relationship between contemplative practices and brain structure/function is an increasing topic of scientific study. There are compelling reasons to assess how yoga and meditation may relate to brain and behavior. Consider the intriguing parallels between changes in neural pathways based on experience and learning (i.e., experience-dependent neuroplasticity) and the concept of samskara in Buddhist and yoga traditions. Changes in the brain following these practices may represent the “burning through” or transformation of maladaptive samskara referenced by ancient yogis and meditators.
Such research has the potential to demystify both positive and potentially negative explanations for the effects of contemplative practice on health and behavior. In the current investigation, researchers used fMRI to compare the resting state brain functional connectivity of 16 Kripalu yoga practitioners, 16 Vipassana meditators and 15 controls (i.e., those with minimal lifetime yoga/meditation practice). This analysis follows on a previously published article that examined different outcomes (i.e., fluid intelligence, brain network integration and resilience) in the same sample.
The researchers found the caudate nucleus (i.e., a brain structure linked with learning and communication) different in contemplative practitioners and controls. Their findings revealed stronger connectivity between the caudate nucleus and other brain regions (i.e., frontal, temporal and parietal) in meditators and yogis than in controls. To test whether these findings could be replicated, the same analysis was conducted on a second sample of meditators versus controls, with remarkably consistent findings.
The caudate is implicated as a key aspect of brain circuits (i.e., basal ganglia-thalamocortical) related to goal directed (rather than habitual) learning. Thus, the researchers theorize that the greater connectivity observed between the caudate and the prefontal cortex may explain positive associations between mindfulness and cognitive and behavioral flexibility (i.e., the ability to change what you are thinking about, and how you are thinking about it, and the ability to flexibly adapt your behavior).
The findings of this study point to the potential promise and limits of brain science. While studies such as these may commonly be reported in the media (guilty as charged), they do not allow us to infer causality because they compared yogis, meditators and control subjects at one time-point, rather than over time. In addition, the precise function, purpose and relationship of many brain regions are still being assessed, with related effects on behavior and psychological health as yet to be definitively ascertained. Thus, while studies like this offer a window into the potential neurophysiological pathways of action through which yoga or meditation may operate, they are still preliminary.
Thankfully, yogic and meditative practices empower you to be a scientist that observes the lab of your own experience. Noticing how you feel when you commit to or skip practice is probably your best source of information.