Mindfulness has been described as an active and open attention to the present moment; an ability to observe an experience as it occurs, from a nonjudgmental viewpoint. Through practice of mindfulness, an individual first begins to recognize patterns of behavior - how the mind naturally attempts to wander off into a plethora of other thoughts - worrying about the future or repeatedly dwelling in the past. Through that recognition, we can gain greater self control and awareness. The practice of mindfulness is not always pleasant, as we tend to divert our attention from present moment experiences when we are trying to avoid emotionally charged topics. But being more "in the moment", we work to self regulate and identify what it is we are experiencing as it is occurring. We learn to accept things as they are and minimize our attempts to try and force reality to fit our vision.
If we look at the brain more in depth, we can understand how impactful mindfulness practices can be. First, there is the 'brain stem', which is a primitive part of the brain. It is responsible for connecting the brain to the rest of the body and regulating basic functions such as breathing, swallowing, heart rate and blood pressure. In direct connection to the brain stem is the limbic system, which houses several well known areas of the brain - hippocampus, amygdala & hypothalamus, to name a few. This area of the brain is responsible for emotions, memories and arousal / stimulation. Both the limbic system and brain stem work together to form the subcortical area of the brain and are responsible for the 'fight or flight' instinct. Much of our impulsive, automatic behaviors are driven by this subcortical region. The prefrontal cortex, which is the area of the brain that ignites the ability to pause before we act, plays a significant role in each of our lives, for obvious reasons. From a psychological perspective, the prefrontal cortex is responsible for executive functions such as decision making, establishing empathy, predicting outcomes and overall, differentiating between 'good' and 'bad'. It is the most developed portion of the human brain. The prefrontal cortex fibers that stem down from it help to calm down and regulate the subcortical area of the brain.