We are at the beginning of a revolution where science is starting to explain what many religious and philosophical pioneers knew instinctually – that much of our suffering is due to how we see the world and react to events and not to the events themselves. Using sophisticated techniques, neuroscientists are mapping various parts of our brain to certain specific activities, abilities and even emotions. As sophisticated as these efforts might be, we are really just scratching the surface and our map covers only a fraction of the territory. This short brief is meant to give an overview and provide a window into what parts of the brain are involved in mindfulness and why mindfulness is useful. To that end, we are going to focus on two areas of the brain: the prefrontal cortex and the posterior cingulate cortex (Figure 1). While the brain is much more complex, a simplified model with these two structures is still very useful in learning why we do the things we do.
First, what is mindfulness? Defining this is harder than one would think because it is more of an experience than a thing. Still, we need a description to teach it and talk about it. A useful description is is awareness that arises through paying attention, on purpose, in the present moment, non-judgmentally1 (ref). Paying attention to the present moment, not thinking about the past or the future but just this moment. “Without judgment” is key. It means that you are accepting whatever life is showing you this very second. You are paying attention to the event itself, not deciding if you like it or not, not wishing for something else to be true, just aware that this event is happening, whatever the event might be. In a future MindSciences Brief we will go deeper into the definition of mindfulness.
Structure: In the early 1900’s, a German scientist named Brodmann divided the brain into numbered regions. For reference, the areas we are focused on are the posterior cingulate cortex (PCC), areas around Brodmann 23 and 31 in figure 2, the prefrontal cortex (PFC) and the orbitofrontal cortex (OFC), a subunit of the PFC, which includes Brodmann 10, 11 and then some.
For our purposes, we can think of the PCC as being an area that gets very active when thinking about ourselves, the future or past. It’s also very active during times of stress, anxiety and even drug craving2. The OFC on the other hand, is a complex decision-making center. It gets information from all the senses and it’s where we rank one thing as being more desirable than another. For instance, somehow the OFC “knows” that you like chocolate more than vanilla ice cream (assuming you do). From an evolutionary perspective, the PCC is part of the limbic system and developed long before the prefrontal cortex (PFC), where the OFC is located. Let that sink in for a minute. The part of your brain that gets revved up in times of stress and self-centered activity (PCC) has been around a lot longer than the part that makes rational decisions (PFC). In fact, only humans have such a highly developed PFC. With the PFC (and sub-unit, OFC), we have the evolutionarily recent capability to make evidenced-based decisions about whats best for us but, just having the tools does not mean we always use them. In practice, most of the time we are being driven by the limbic system, sometimes called the lizard or “reptilian” brain because that is pretty much all a lizard has. Importantly, we are built such that the more the limbic system is active the less the PFC is and vice versa. We will come back to this.
Why is Meditation always mentioned with Mindfulness?
As described, mindfulness is a state of calm, non-judgmental awareness. To learn how to be in that state all of the time takes practice, but over thousands of years people have found meditation to be one of the best tools to learn this with. Just like one needs to learn to walk before one can run, meditation is the most common path to mindfulness.
In times of stress, the brain naturally defaults to the limbic system and literally takes the PFC partially offline. In other words, when stressed, we use our lizard brain more and our rational brain less. Note that the word stress here captures a lot of things ranging from true fear, to frustration, to simply being tired. The lizard brain was built to make very simple decisions based on a limited number of choices. Relying on it in today’s world often results in bad choices, choices you are often not even aware you are making.
Over the past several decades, by looking at brains of people meditating and various other activities, scientists have actually seen these areas of the brain not only get more and less active but even get denser3 and change connectivity patterns4, depending on the training. Remember that when the PFC is active the PCC is less active. We have been able to clearly relate a less active PCC with decreased levels of stress, increased calmness and even joyful feelings5. What mindfulness allows then is, among other things, the ability to keep the PFC online so that the rational more advanced brain is part of your decisions. When you are in this state, you are more engaged, you make better decisions, are happier and those around you are happier too.
- What about the “Self” is Processed in the Posterior Cingulate Cortex? Brewer JA1, Garrison KA, Whitfield-Gabrieli S.; Front Hum Neurosci. 2013 Oct 2;7:647. doi: 10.3389/fnhum.2013.00647
- Mindfulness practice leads to increases in regional brain gray matter density. Britta K. Hölzelab ,James Carmodyc, Mark Vangela, Christina Congletona, Sita M. Yerramsettia, Tim Gardab, Sara W. Lazara; Psychiatry Research: Neuroimaging, Volume 191, Issue 1, 30 January 2011, Pages 36-43
- Impact of mindfulness-based stress reduction training on intrinsic brain connectivity. Lisa A.Kilpatrickac,Brandall Y.Suyenobuac, Suzanne R. Smithac, Joshua A. Buellerac, Trudy Goodmang, J. David Creswellf, KirstenTillischac, Emeran A. Mayeracd ,Bruce D. Naliboffabe; NeuroImage Volume 56, Issue 1, 1 May 2011, Pages 290-298
- The Craving Mind: From Cigarettes to Smartphones to Love? Why We Get Hooked and How We Can Break Bad Habits. Judson Brewer, MD: Yale University Press, 2017