NRSC 4132 Blog

Recent consensus numbers indicate that roughly 20 million, or about 10%, of the current U.S. population reported practicing meditation in the last year! To many of us at CU, the practice of meditation is all too familiar - Boulder, CO is one of the most yoga- and meditation- active cities in the U.S.

A recent study in the Journal of Neuroscience by Zeidan et. al (http://www.jneurosci.org/content/31/14/5540.abstract) analyzes an interesting application of meditation: modulation of pain. In particular, the Shamantha model of meditation was examined, one which involves sustaining attention on the "changing sensations of breath, monitoring discursive events as they rise, disengaging from those events without affective reaction, and redirecting attention back to breath". In this study, the discursive event was pain, and subjects were assessed for their ability to dissociate cognition of the pain stimulus from pain response.

The study employs a novel form of fMRI called pulse arterial spine labeled (PASL) MRI, a form of imaging that quantifies cerebral blood flow (CBF). Blood oxygen-level dependent (BOLD) fMRI, the conventional form of fMRI, is useful for monitoring short spurts of activity, but it is susceptible to slow drifts in signal intensity over extended periods of time. Because the practice of meditation often requires ample time, PASL MRI is better suited than BOLD fMRI.

The experiment consisted of 15 healthy volunteers. Three groups were sampled: a control group that received no training, an experimental group that only received directions to focus attention to breathing (ATB), and an experimental group that was taught Shamantha meditation. Each group was brought into a neutral environment and was presented with a 6 min. noxious heat stimulus (at 49 deg Celsius), during which the control group was instructed to rest, the ATB group to focus on breathing, and the meditation group to meditate. Two MRI readings were taken on all groups during presentation of noxious stimuli: pre- and post-meditation training. Additionally, test subjects were asked to rate unpleasantness of pain through the Freiburg Mindfulness Inventory (FMI) shortform.

Interestingly, the results show that attention to breath alone has no effect on modulating pain response; ratings of pain intensity and unpleasantness were identical between the control and ATB groups prior to meditation training. After meditation training, the experimental groups exhibited a 57% decrease in pain unpleasantness ratings and a 40% decrease in pain intensity ratings relative to the control group. Statistical analysis shows that meditation-induced reductions in pain were associated with increased activity in the anterior cingulate cortex and anterior insula, areas involved in the cognitive recognition of pain. This may seem paradoxical at first, as a majority of past studies have reported increased activity of these areas increases pain experience.

It is important to note that Zeidan et. al clarify the increased activity of these areas with the concurrent reduction of activity in the orbitofrontal cortex (OFC), an area of the brain associated with emotional evaluation and response. Grant et. al (http://www.ncbi.nlm.nih.gov/pubmed/21055874) report a similar de-coupling of the dorsolateral prefrontal cortex (DLPFC) and the cingulate, suggesting that the DLPFC (like the OFC) functions to generate emotional response after the cingulate receives afferents from pain stimuli. Given this novel model of pain, it is not surprising that the anterior cingulate cortex and anterior insula were active in meditating individuals; the heightened activity of these areas allowed them to be aware of discursive events (pain stimuli), but the reduced activity of the OFC allowed them to dissociate their pain response and refocus their attention to breathing.

These results show that meditation may be a powerful, natural way of dealing with pain. In an era where opiates and pain relievers are often relentlessly abused, meditation may be the perfect solution. Maybe one day, we'll see NFL athletes meditate at the end of practices and games, or physical rehabilitation patients meditate daily to overcome the pain of a healing injury. Only time, and more research, can tell.