 Meditation results in changes in cognition, sensory perception, affect, hormones, and autonomic activity. Until today, there have been very few imaging studies of the neural correlates of meditation. Instead of evaluating the meditation practice itself, our approach is to evaluate the neural correlates of performance modulation on an attention paradigm the Stroop word-color task; SWCT and an emotional paradigm the frustration paradigm before and after a meditation retreat. The following categories of individuals will be invited to participate: healthy regular meditation practitioners at least three years of practice, three times a week, individuals inexperienced in meditation, and patients with a cancer diagnosis. The total sample will comprise 96 individuals who will be allocated to groups of sesshin meditation, rest groups and groups that will keep their daily activities. If they wish to do so, those who participate in the two latter groups may also receive training on meditation. The subjects will be between 18 and 65 years old and have no contraindication to the fMRI exam. After signing an informed consent form, the subjects will answer anxiety, depression and stress inventories; scales that evaluate their feelings of self-compassion and mindfulness, as well as the Stroop Color Word task and an emotional paradigm of functional Magnetic Resonance Imaging. 