Cortical thickness and pain sensitivity in zen meditators.

Zen meditators show lower pain sensitivity than non-meditators, and this difference is linked to thicker gray matter in brain regions that process pain, including the anterior cingulate cortex, parahippocampal gyrus, and anterior insula. In a structural MRI study of 17 meditators and 18 controls, meditators had thicker cortex in the dorsal anterior cingulate and secondary somatosensory cortex. More years of meditation experience predicted thicker gray matter in the anterior cingulate, and more hours of practice predicted thicker gray matter in somatosensory regions representing the lower leg and hand. The findings suggest that long-term meditation may alter brain structure, contributing to reduced pain sensitivity.

Study at a glance

Abstract

Zen meditation has been associated with low sensitivity on both the affective and the sensory dimensions of pain. Given reports of gray matter differences in meditators as well as between chronic pain patients and controls, the present study investigated whether differences in brain morphometry are associated with the low pain sensitivity observed in Zen practitioners. Structural MRI scans were performed and the temperature required to produce moderate pain was assessed in 17 meditators and 18 controls. Meditators had significantly lower pain sensitivity than controls. Assessed across all subjects, lower pain sensitivity was associated with thicker cortex in affective, pain-related brain regions including the anterior cingulate cortex, bilateral parahippocampal gyrus and anterior insula. Comparing groups, meditators were found to have thicker cortex in the dorsal anterior cingulate and bilaterally in secondary somatosensory cortex. More years of meditation experience was associated with thicker gray matter in the anterior cingulate, and hours of experience predicted more gray matter bilaterally in the lower leg area of the primary somatosensory cortex as well as the hand area in the right hemisphere. Results generally suggest that pain sensitivity is related to cortical thickness in pain-related brain regions and that the lower sensitivity observed in meditators may be the product of alterations to brain morphometry from long-term practice.