There is a well written post on the Scientific American blog about what mindfulness does to the brain.  I have been working with athletes and teams, trying to teach them to use mindfulness exercises in simple and straightforward ways to regulate their reactivity.  Mindfulness, when practiced regularly,  changes the key centers such as the amygdala, the small almond shaped area at the center of the limbic system and the site of fight or flight responses.  When the amygdala is stimulated in animals in experiments, they demonstrate fear and/or rage.  This site actually shrinks with the practice of mindfulness meditation.   Our schools, military, coaches and business leaders are beginning to teach this simple skill to help us to be more thoughtful and focused.  Read the article here: http://blogs.scientificamerican.com/guest-blog/what-does-mindfulness-meditation-do-to-your-brain/