these regions to guide our ongoing behavior
Importantly, the meditators with the biggest
disconnection between these regions were those that required the hottest temperatures to report
pain. It is also important to keep in mind that these results are from the baseline condition. This
suggests that the meditators can modulate pain “on the fly” and raises interesting predictions as to
how their brains look during meditation. Those data are still in the process of being analyzed.
Taken together, the results of this study lend some support to ancient Buddhist claims, which posit
two aspects of pain: the sensation itself (first arrow) and the suffering that the mind creates as a
result (second arrow)
The results also corroborate the claim that through meditative training one
can remove the second arrow of pain.
Importantly, studies by several teams appear to support this interpretation, with consistent findings
across different meditation traditions. An imaging study of Vipassana meditators also found
reduced pain with increased activation of pain-related areas (INS) and decreased lateral frontal
activity during pain in a meditative state
A soon-to-be-published study from a group in
Wisconsin found strikingly similar results in advanced Tibetan meditators. The story may be a little
different for beginning meditators. Following a mere four days of training, previously untrained
individuals showed dramatically reduced pain
Activation was decreased in SI, while reduced
pain reports correlated with increases in INS, ACC and orbitofrontal cortex (OFC). In a recent
review of the meditation/pain literature, we suggested that mindfulness may involve several
mechanisms that are partly dependent upon experience level
The pain-area activations
(ACC/INS), alongside reduced pain (opposite to typical findings), suggest a novel form of sensory
monitoring where the physical properties and aversive nature of the experience are dissociated.
We suggested that beginners may accomplish this by reappraising their experience, reflected in
the OFC activations, whereas advanced practitioners may actually refrain from appraisal
altogether, evidenced by the widespread, but particularly frontal, deactivations. Interestingly, the
ACC and INS are known to code stimulus saliency
, which may indicate that practice enhances
certain aspects of the stimuli. Alternatively, these activations may reflect the processes required to
carry out the practice itself. Other mechanisms such as reductions in anxiety, fear and
anticipation
likely also have a role in mindfulness-related pain reduction. Studies attempting to
tease apart the mechanisms of meditation-based analgesia are underway in a number of groups
around the world.
One implication of the baseline effects our group has observed is that training seems to have
lasting effects on a person. This is clearly important if such practices are to be useful in everyday
life. MRI also allows us to take detailed images of brain anatomy and quantify different tissues,
giving us an index of longer term changes. In a separate study, we measured gray matter
thickness in Zen practitioners and controls
. The gray matter is the thin sheet of cells covering
the outer surface of the brain that does the brain’s computing. We discovered that the meditators
also had thicker gray matter in several pain-related brain areas including the ACC. Recall that the
ACC played a major role in the functional MRI results explained above. Further, meditators with
more experience had thicker gray matter in this region and a thicker ACC was associated with a
higher temperature required to report moderate pain. Thus, there is evidence that meditating
changes the physical structure of the brain in highly specific ways, which may explain the ability to
modulate pain. However, one cannot exclude the possibility that meditators had thicker brains even
before they began to practice, although this seems unlikely given the relationship with their level of
experience. Further, there is now a report demonstrating change in gray matter following an 8-
week meditation program
. Following the intervention, participants had gray matter increases in
the hippocampus, posterior cingulate, temporo-parietal junction and cerebellum. And now you
might ask yourself, wasn’t this chapter supposed to have something to do with compassion?
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