What happens with brain activity when you're meditating? In Richie Davidson lab at the University of Wisconsin–Madison, they asked some expert meditators to meditate and compare their brain waves measured with EEG to a novice meditator's. What they found is that instead of the brain quieting down when subjects meditated, there was increase in brain activity, and really increase in synchrony between different brain areas. And the more experience, the higher the synchrony. The expert meditators get into what is called gamma synchrony, which is a very fast brain activity. These activities were mostly detected in the insula, amygdala and cingulate cortices, the limbic system. Doctors Chuck Ryazan from the Department of Psychiatry in the Brain Health Center at Emory and Dr. Nagy in the Department of Religious and Tibetan Studies researched inflammation and how meditation affects it. Inflammation is involved in multiple brain diseases, and those that affect the nervous system, such as stroke and heart disease, Alzheimer's, multiple sceloris, neuropathic pain and other diseases like diabetes.
A large scale randomized clinical trial testing the physiological effects of meditation was done in a collaboration with Emory University and Boston University in collaboration with Harvard and the Massachusets General Hospital. In this study, healthy participants between the ages of 25 and 55 were recruited and divided into three groups. A control group, trained in compassion meditation and a group that was trained in mindfulness meditation. They recruited 360 subjects of different ethnic and racial backgrounds, and followed them over a period of 5 years. They had eight weeks of training, where they met twice a week for one hour of teaching. The subjects were then asked to meditate between 20 and 30 minutes per day, and their practice was tracked through tracking devices. The controls were asked to journal. There was no exercise or change in diet so as to not interfere with the results.
For the mindfulness group, they used what is called the MAP protocol, or mindfulness attention training. This was designed by Alan Wallace from Santa Barbara Institute for Consciousness and Dr. Nagy at Emory University based on Tibetan Buddhism, but it was completely secular in content. Subjects were taught how to sustain their attention so they would start their practice with the attention to the breath, and like everybody else, their mind would wander. However, they were taught how to settle their mind and how to train your meta awareness, in other words, the awareness of the awareness. The other group, the compassion group, was taught the compassion meditation protocol.
In this group, the practice also starts with attention training, but they were also taught to develop compassion for oneself and to develop affection and empathy for others. The third group, the control group, followed an eight-week protocol of meeting for a one hour talk in small groups about health topics that were important to them, and asked them to journal about their health rather than to meditate. The participants then took Trier social stress test, or TSST, a well validated way of inducing stress. It's done by interviewing a subject for a mock job interview in front of a panel of expert behavioralists.
Subjects were also made to do math. They then measured stress response with the subject's sweating with a skin conductance level, and their heart rate variability. They also collected blood work to test for interleukins, cortisol levels, norepinephrine levels, and other markers of inflammation. These measured were collected before, during, and after the stressful events. Changes in stress response involve many areas of the brain, especially the limbic structures, such as the hypothalamus, pituitary, and adrenal axis, or the axis between the brain and the adrenal glands for stress response with cortisol. The questions this study sought to answer included which neural regions and circuits are involved. Is neuroplasticity involved and how does it differ between different types of meditation?
The results of the calm study showed that levels of interleukin-6, which is a marker of inflammation, was much higher in the control group than in the meditation group, even following a dose response. Same thing for cortisol, which is a potent stress neurotransmitter, even when levels were similar prior to the test. In other words, the more you meditate, the less inflammation and stress.