Study: Functional-Anatomic Fractionation of the Brain’s Default Network (PDF)
The first crucial step to understanding the science of meditation is to understand the Default Mode Network (DMN). The Default Mode Network (DMN) is an interconnected set of brain regions that play a particularly important role in the management of attention, awareness, and our internal sense of self. The two main regions involved, apparently functioning as connection hubs for a slew of other minor brain regions; the primary hubs of the DMN include:
- the posterior cingulate cortex (PCC) and
- the anterior medial prefrontal cortex (amPFC)
Regions involved in the DMN are pictured.
These regions are likely candidates for deep structures of the psyche like sense of self and orientation as a self in space and time. The study notes:
Tasks that encourage subjects toward internal mentation, including autobiographical memory, thinking about one’s future, theory of mind, self-referential and affective (emotional) decision making, tend to activate regions within the Default Network.
We can determine the correlates between brain states and subjective accounts because when the brain regions in question are deactivated or down-regulated, the person reports different descriptions of their own subjective experience. For a simple example, “mindful-attention and compassion meditation training” seems to have rather large effects on the amygdala response in participants in only a few days of meditation training (Desbordes, 2012, pdf).
“Anatomically, the default network comprises regions along the anterior and posterior midline, the lateral parietal cortex, prefrontal cortex, and the medial temporal lobe (Buckner et al., 2008).”
There are strong correlations between deactivation of these Default Mode regions in fMRI scans and the subjective reports the subjects give about their sense of self, self-referential thoughts, and orientation in spacetime.
DMN and Buddhism
I suspect, selfless awareness is a real experience you can have: with some training and practice, you can absolutely get into a certain kind of meditative state, almost like a trance, where your sense of self does in fact drop away. This has been claimed by Buddhist for man centuries, and we now have real scientific evidence to back this claim up. As I will show in the next study, the default mode network is highly associated with meditation practices and probably explains the canonical Buddhist teachings of no-self and emptiness.
Study: “Meditation experience is associated with differences in default mode network activity and connectivity” (PDF)
In this study, researchers who were already familiar with the Default Mode Network paradigm predicted that the DMN would be an important brain region related to the subjective effects of meditation. They took a group of trained, experienced meditators (and a group of controls) and subjected them to fMRI brain scans during meditation practices and baseline. The results were rather astounding, and confirm the theory that the DMN may be involved with meditation and the subjective sense of no-self: it is pretty clear from this study that experienced meditators have significant decrease in electrical activity in the PCC and mPFC, the two main hubs of the DMN.
Again we are getting back to the main point, which is that meditation has significant impacts on certain parts of your brain that control your sense of self, time and space. The PCC and MPFC are the two core hubs of the default mode network, and these are down-regulated pretty consistently in three different types of meditation. To me this is a huge connection between brain science, psychology, and meditation that cannot be understated.
Through specialized practices you can come to control these brain regions responsible for mind-wandering and rumination, which before the training would have got their way and ruled over the personality like a mean schoolyard bully. As it turns out, the parts of our brain likely responsible for the internal voice, the judge, are anatomical regions like the amygdala that can, through specific training, be allowed to atrophy and therefore down-regulated. This is the light at the end of the tunnel, that somehow through these concentration exercises you can begin to retrain and rewire parts of your mind that have caused endless suffering, anxiety, and completely obsessive analytical thinking.
In my own experience, meditating consistently over the years has led to an incremental reduction in that judgemental, paranoid self-referential voice in my head. There wasn’t a day when it just suddenly wasn’t there anymore, it just atrophied and was eventually replaced by stronger, more adapted parts of my personality. Thousands of other people alive today have experienced this too, you can even dig around on Reddit for the Shinzen Young or Mind Illuminated threads and see active forums of people pursuing these practices and trying to obtain consensus over how the stages and practices work.
Why Sit and Stare at a Wall?
I hope I have demonstrated the neural correlates between specific meditation protocols and subjective brain states, and show the multitude of potential psychological and physiological benefits of meditation. I do this not for the sake of progressing neuroscience, touting personal accomplishments, or even some desire to be right about something; rather, I hope to make it clear to you that there are approaches to spirituality and personal growth that have real scientific backing to them. Ultimately contemplative spirituality is about transformation, so I hope that you take these models and findings and apply them for yourself in your own practice. Don’t take my word for it, and don’t take the word of any study or scientific paper either: become a living Buddha and find out how this process unfolds in your own life. Without actually seeing for yourself, this is all highly speculative and won’t create a lasting change in your consciousness. See here How To Meditate.
I want to stress that the main benefit of meditation that you’ll notice in the studies and the story I’m now weaving about those studies, is that rumination, mind-wandering, turns out to be nothing more than a severely bad habit (or addiction). This statement – that the wandering mind is a learned habit – is pretty clear to me now, but it took me years to realize this, years! I thought that living with rumination and mind-wandering were the normal for everyone all the time, and I had no idea that the purpose of meditation was to completely eliminate mind-wandering forever. The continual stream of self-referential thoughts, though seemingly a permanent trait of the human brain, is a learned, habitual, action.
What I hope you’ll find is this: through various contemplative practices, including seated meditation, this addiction to thinking can be cured; and positive mental states can flourish. This shift of operation out of thought and into awareness is equivalent to a complete paradigm shift and a new way of living life – this is what is meant by ‘awakening.’