Meditation reduces pain-related neural activity in the anterior cingulate cortex, insula, secondary somatosensory cortex, and thalamus

Meditation appears to reduce pain perception, but neuroimaging studies have produced paradoxical results: some show increased neural responses in the anterior cingulate cortex (ACC) and insula during meditation, while others show decreases. Since activity in these regions typically correlates with pain perception, increases would seem to enhance rather than reduce pain. This review synthesizes previous findings on brain regions involved in meditation and anatomical changes from long-term training, then discusses pain-related neural activity during meditation. The authors hypothesize that meditation reduces pain-related neural activity in the ACC, insula, secondary somatosensory cortex, and thalamus, and suggest that the modulation's characteristics may depend on the type of meditation and years of experience, potentially explaining the paradoxical evidence.

Study at a glance

Abstract

Recent studies have shown that meditation inhibits or relieves pain perception. To clarify the underlying mechanisms for this phenomenon, neuroimaging methods, such as functional magnetic resonance imaging, and neurophysiological methods, such as magnetoencephalography and electroencephalography, have been used. However, it has been difficult to interpret the results, because there is some paradoxical evidence. For example, some studies reported increased neural responses to pain stimulation during meditation in the anterior cingulate cortex (ACC) and insula, whereas others showed a decrease in these regions. There have been inconsistent findings to date. Moreover, in general, since the activities of the ACC and insula are correlated with pain perception, the increase in neural activities during meditation would be related to the enhancement of pain perception rather than its reduction. These contradictions might directly contribute to the 'mystery of meditation.' In this review, we presented previous findings for brain regions during meditation and the anatomical changes that occurred in the brain with long-term meditation training. We then discussed the findings of previous studies that examined pain-related neural activity during meditation. We also described the brain mechanisms responsible for pain relief during meditation, and possible reasons for paradoxical evidence among previous studies. By thoroughly overviewing previous findings, we hypothesized that meditation reduces pain-related neural activity in the ACC, insula, secondary somatosensory cortex, and thalamus. We suggest that the characteristics of the modulation of this activity may depend on the kind of meditation and/or number of years of experience of meditation, which were associated with paradoxical findings among previous studies that investigated pain-related neural activities during meditation.