People can reduce their sensitivity to pain by thickening their brain, according to a new study published in a special issue of the American Psychological Association journal, Emotion. Researchers from the Université de Montréal made their discovery by comparing the grey matter thickness of Zen meditators and non-meditators. They found evidence that practicing the centuries-old discipline of Zen can reinforce a central brain region (anterior cingulate) that regulates pain.
Source: http://www.sciencedaily.com/releases/2010/02/100224103357.htm