The mind (energy and information flow in the brain) is created by the brain. Our brains learn mostly by what the mind attends to, and what we attend to necessarily change’s our brain. For example, when we remember a joyful occasion, we are more prone to be playful and creative in the present moment. It follows that how we choose to focus our attention (how we intentionally direct the flow of energy and information) alters our brain chemistry, and literally changes our mind, which then changes our brain! As a result of any mental activity our neurons begin to make connections, and the longer we attend to a thought or experience, the deeper those connections become, and the more likely we are to re-experience them again.
Read more here.