title: Insular cortex mediates increased pain tolerance in yoga practitioners.
abstract: Yoga, an increasingly popular discipline among Westerners, is frequently used to improve painful conditions. We investigated possible neuroanatomical underpinnings of the beneficial effects of yoga using sensory testing and magnetic resonance imaging techniques. North American yogis tolerated pain more than twice as long as individually matched controls and had more gray matter (GM) in multiple brain regions. Across subjects, insular GM uniquely correlated with pain tolerance. Insular GM volume in yogis positively correlated with yoga experience, suggesting a causal relationship between yoga and insular size. Yogis also had increased left intrainsular white matter integrity, consistent with a strengthened insular integration of nociceptive input and parasympathetic autonomic regulation. Yogis, as opposed to controls, used cognitive strategies involving parasympathetic activation and interoceptive awareness to tolerate pain, which could have led to use-dependent hypertrophy of insular cortex. Together, these findings suggest that regular and long-term yoga practice improves pain tolerance in typical North Americans by teaching different ways to deal with sensory inputs and the potential emotional reactions attached to those inputs leading to a change in insular brain anatomy and connectivity.
authors.affiliation: Alan Edwards Centre for Research on Pain, National Center for Complementary and Alternative Medicine (NCCAM), National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Chantal
authors.initials: C
authors.lastname: Villemure
authors.affiliation: Alan Edwards Centre for Research on Pain, Integrated Program in Neuroscience, McGill University, Montreal, Canada and National Center for Complementary and Alternative Medicine (NCCAM), National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Marta
authors.initials: M
authors.lastname: Ceko
authors.affiliation: Alan Edwards Centre for Research on Pain.
authors.forename: Valerie A
authors.initials: VA
authors.lastname: Cotton
authors.affiliation: Alan Edwards Centre for Research on Pain, Faculty of Dentistry, Department of Anesthesiology, Department of Neurology and Neurosurgery, Faculty of Medicine, Integrated Program in Neuroscience, McGill University, Montreal, Canada and National Center for Complementary and Alternative Medicine (NCCAM), National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: M Catherine
authors.initials: MC
authors.lastname: Bushnell
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D056324:Diffusion Tensor Imaging; D005260:Female; D066128:Gray Matter / Q000033:anatomy & histology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D058748:Pain Perception; D017288:Pain Threshold / Q000523:psychology*; D066127:White Matter / Q000033:anatomy & histology; D015013:Yoga / Q000523:psychology*
keywords: DTI; VBM; insula; pain tolerance; yoga practice