If you remember from our introduction to the brain, the frontal lobes and limbic brain are responsible for what you would associate with us as human beings, feelings, analytical thinking, and such. What happens during meditation? When I started, I used to sit there and try not to think about anything. And then inevitably, I would start thinking about what I was going to make for dinner, my leg would start tingling or an itch on my nose would come out of nowhere. My attention would go to that and then I would get annoyed with myself for letting my mind wander.
Turns out this is what happens to everybody, at least in the initial stages of meditation. You sustain your focus through breathing a mantra and then your mind wanders and you become aware that your mind is wandering and you shift your attention back to your breath or whatever your anchor was. Your prefrontal cortex lights up when you start meditating and focus your attention on breathing. Then your mind wanders and different areas in your brain light up, this is called a default mode network. Every time you daydream your default mode network is working, so your brain is never off. Then you become aware that your mind wandered and that's when your insula lights up. You then decide to get back to your focus mode and your prefrontal cortex and parietal lobe light up. This was studied in an MRI scanner. People were asked what they were thinking about when their mind was wandering and mapped it to different brain areas. Autobiographical memories, thinking about your own life, which lights up your prefrontal cortex. And when you think about the future, your posterior cingulate cortex lights up. Moral decision making lights up both the prefrontal cortex and the posterior cingulate cortex. Meaning you are projecting yourself in the future and looking at your past for clues to decide what to do.
Recent studies show that meditation increases the size of your brain. Particularly the gray matter, which is where the bodies of your neurons are and the processors of your brain.
That's where all the machinery of the brain exists. Your white matter is made up of the cables between this different machinery.
An increasing size of the gray matter was found mostly in the insula and prefrontal cortex. In contrast you gray matter decreases in size with aging, and even more so in dementia. So you see the potential applications of this practice. Jon Kabat-Zinn's mindfulness based stress reduction has been studied extensively. And shows that after only eight weeks you can improve chronic pain, anxiety, depression and some auto immune diseases such as psoriasis. This was shown in randomized control studies which is among the highest degree of trial you can achieve. This exact mechanism by which MBS works are still being studied. In a study by Holzerlau in 2011, short 30 minutes of meditation a day done over eight weeks, showed measurable changes in the size and density of the gray matter in areas of the brain associated with memory, stress and sense of self. It also showed increased size of the hippocampus, or learning areas. The hippocampus is the area that shrivels with cognitive decline and dementias. Not only did meditation increase gray matter in these areas, it also caused a decrease in the gray matter in the amygdala which is your alarm system. And it's connected with anxiety.