In order to assess the potential benefits of any meditation technique, we must consider in detail what happens in the body, especially in the brain but also overall in the central nervous system. This is the case with Mindfulness meditation, a technique derived from Vipassana meditation, a practice which medical professor Jon Kabat-Zinn has « secularized » so that it would be readily accepted in all strata of American society. This apparent « secularism » has allowed Mindfulness to spread easily, especially in the medical community. The practice can be learned by simply reading a book on the subject as these usually have an accompanying CD, by informing oneself over the Internet or by participating in a paid, eight-week structured course. This meditation technique consists of training the mind to focus on the present moment by putting one’s attention on the breath or on any other bodily processes, without making a value judgment. This attention can be maintained outside the strict framework of “eyes-closed” meditations, and can be practiced while eating, walking, working, etc. Several studies show that Mindfulness is quite effective in reducing stress, anxiety, pain or fighting against the recurrence of depression. How does Mindfulness meditation, Mindfulness in short, affect brain functions? Before answering this question, a side step is necessary to review how our brain works.