The positive effects of mindfulness meditation on pain and working memory may result from an improved ability to regulate a crucial brain wave called the alpha rhythm. This rhythm is thought to "turn down the volume" on distracting information, which suggests that a key value of meditation may be helping the brain deal with an often overstimulating world.

Read more http://www.eurekalert.org/pub_releases/2011-04/mgh-mmh042111.php