Do you ever just wish you could get someone who knows virtually everything that’s known about the brain and quiz them about mindfulness? Well, I do – a lot – and I just got my wish!
It is my pleasure to present this interview with John McBurney MD. A practicing physician with of over 35 years’ experience, he is board certified in Neurology, Clinical Neurophysiology and Sleep Medicine. He holds an Integrative Medicine Fellowship… The list of his professional accomplishments is obscenely impressive, so I will jump to the bit we all really want to know about: Dr. McBurney maintains a daily mindfulness meditation practice as well as home yoga practice, hence the downward facing bit. Needless to say, I was beyond curious to find out his understanding of how mindfulness affects the brain.
For those of us who are put off by the mystical connotations that surround mindfulness, could you take us back to a schematic, reflex-arc type view of the process and describe the neurological response to mindfulness practice?
I think that the issue of mindfulness intersect with the leading-edge of neuroscience. It is supported by extraordinarily robust data. This area of study has been termed contemplative neuroscience. The Mind and Life Institute which is an outgrowth of the dialogues between the neuroscience community and the Dalai Llama is an important sponsor of research and education on contemplative neuroscience. It ultimately comes down to the concept of neuroplasticity.
Donald O. Hebb coined the doctrine: “neurons that fire together, wire together”. It was an extension of the work done by an American philosopher and psychologist William James in the early XX century. You can practice “bad” things or “good” things – and neuronal ensembles form accordingly. In mindfulness, we are essentially practicing good things.
There is a resting ensemble of neural networks called the default mode network that was discovered using fMRI studies where individuals were asked to lay in the scanner and think of nothing in particular. This kind of mindless mental activity is accompanied by a lot of self-referential ruminative recursive thoughts that are subserved by brain regions that lie along the midline, especially the prominent in medial parietal lobe. Those types of internal mental states that are remarkably robust and persist under deep general anaesthesia and even in a coma and are probably the neural basis for the self.
The more outward facing parts of the brain – like the dorsolateral prefrontal cortex – are more responsible for an outward orientation to the world have top down executive influence on the activation of those networks.
In mindfulness, in cultivating awareness of the breath and voluntary moment by moment awareness of the brain, we are training the brain – just like when you are learning to play the violin or any other complex skill – we are training to break out of those self-referential ruminative recursive mental states and to achieve an orientation toward the outer world and in the present moment rather than anticipating the future or reliving the past.
There is evidence that mindfulness leads to weaker connections in default mode network. Could we be losing something by focusing more on the external realities rather than the self?
Not everyone has a well formed default mode network. People who have been subjected to severe developmental trauma, neglect and lack secure attachment do not have robust default mode networks. Mindfulness can lower defence mechanisms that are there with good reason. However, most people with a well formed default mode network and secure attachment. We are “taming an elephant”: there is very little chance that we will significantly weaken the elephant.
Occasionally, we do hear of adverse experiences arising from mindfulness. With any robust intervention there are always potential risks.
How long does it take for mindfulness to have a manifest effect?
The results can happen almost immediately, however, they are also cumulative. We are still figuring out what the minimum effective dose it. This reminds me of the discussion of the minimum effective dose of aspirin in stroke and heart attack prevention. When I was a resident, we were advising patients to take two 325 mg tablets twice a day. Over time this dropped to 81 mg of aspirin a day. There is speculation that the required dose may even be lower.
There is a study that defines a new marker. The original fMRI/EEG studies were done by Richard Davidson in Tibetan Buddhist meditators with over 10,000 hours of meditation. This number is somewhat arbitrary and refers to this idea that is the number of hours to become an expert at anything. However, the question arises: what is the relevance of the changes in functional connectivity in the brain in someone who has devoted such a monumental amount of time to meditation to the likes of you and me?
A very neat study was published by David Cresswell in Biological Psychiatry in 2016. They invited individuals with high level of stress, unemployed adults, to a weekend retreat experience. They were randomised to in 2 groups:
- a 3 day mindfulness retreat (the treatment group) and
- a 3 day relaxation retreat where they read stories, told jokes and had a good time (the control group).
The study was conducted in one centre over one weekend, so it is well controlled. Initially, both groups rated the interventions as being equally helpful to them, subjectively.
The researchers looked at the functional connectivity between the dorsolateral prefrontal cortex and the cingulate gyrus. They also looked at Interleukin-6, a known marker of inflammation, that has been previously shown to be elevated in stressed out unemployed people.
Even with this brief weekend mindfulness intervention, the treatment group developed increased connectivity between the dorsolateral prefrontal cortex and the cyngulate gyrus. There was a neuroplastic response even after a 3 day mindfulness retreat. This was also associated with a decrease in the marker IL-6. Even after 4 months, IL-6 was decreased in the treatment group, but in the control group, IL-6 levels continued to rise, independent of whether they managed to get a job or not.
This is also relevant to doctors, who are at high risk for burnout. Because of their work commitments, the mindfulness retreat for doctors was condensed from the standard 8 week model developed by John Kabat-Zinn to a weekend intervention. The question was: does the weekend model work? The research at the University of Wisconsin where this was developed was reassuring: the residents are less stressed out, more effective and have a greater level of satisfaction.
We still don’t know the absolute minimum dose, but it seems that a weekend of mindfulness can be life-changing for the brain.
Another paper published in PLOS ONE from the Benson-Henry Institute for Mind Body Medicine in Harvard looked at the practices such as meditation, prayer, mindful yoga, Tai-Chi, Qi Gong, etc, i.e. ones that elicit a relaxation response (as opposed the stress response).
This study showed that in both novice and experienced practitioners of relaxation response modalities, there were changes in the epigenetic transcription of the genome. There was upregulation of pathways associated with mitochondrial integrity, downregulation of inflammatory pathways, improved insulin-related metabolism and improved nitric oxide signalling.
Long term potentiation, the standard mechanism for memory formation, strengthens existing neural connections. This happens immediately, as you read this. Over time, long term potentiation leads to formation of new connections,through synaptogenesis, dendritic arborisation and neurogenesis i.e. brain structure changes. In turn, this affects the most neuroplastic neurons located in the hippocampus.
In reference to this fascinating recent study of the fight or flight response, it seems plausible that breathing regulates our stress levels much more than conscious thought. Could you explain the significance of this in terms of mindfulness?
The ancients believed that emotions reside in the body. This comes up a lot in serious yoga classes.
This highly innovative study shows that the control of the adrenal medulla – the main effector of the stress response – is not from the conscious ruminating thinking centres, but by the motor and sensory cortex.
This explains why breathing, as well as yoga and Tai-Chi, are an important part of meditative practice. In my experience, these kind of interventions do affect the stress response in a beneficial way.
Mindful exercise exists in many form. For example, weightlifters need to be very mindful to maintain perfect form. Cycling is another example: it is vital to concentrate on every pedal stroke and maintain an even cadence. Once you start to day dream, you notice straight away that your output is way worse. This overlaps with the concept of flow. It is about getting in the zone. There is a very inspiring TED talk by Judson Brewer MD, Ph.D. that explains the physiology behind flow and how it is augmented by mindfulness. Mindfulness is work, and it does require discipline. There is a paradox here of non-striving and non-doing while also being disciplined.
You are a sleep medicine expert. Could you comment on the relationship between mindfulness and sleep?
Insomnia is a complex problem with many causes. However, for most people with idiopathic insomnia, the cause it these self-referential recursive ruminations. They aren’t able to “turn their brain off”. Through mindfulness practice, they are generally able to tame the default mode network that’s responsible for ruminating and daydreaming. A simple strategy would be to lie in bed and concentrate on the breath. This would ease the transition between wakefulness and sleep.
Mindfulness is a mainstay treatment for many mental health disorders. What about use of mindfulness in the treatment for organic pathology of the brain usually treated by neurologists?
There is some preliminary data that mindfulness training has a beneficial effect of seizure frequency in patients with epilepsy. It is a medical condition associated with tremendous anxiety and stress, so mindfulness could have a significant benefit in more than one way. It may even have a benefit it terms of remembering to take medication on time, etc.
Some robust studies show that the frequency of relapse in multiple sclerosis decreases with mindfulness intervention. The effect from mindfulness is similar in magnitude to the effect from beta-interferon. There is also some research showing that the frequency of inflamed Gadolinuim-enhancing lesions decreases with mindfulness.
John Kabat-Zinn used to take the patients who suffered from chronic pain or had diseases for which we had no answer, and those patients got better. Even beyond neurology, there is some evidence that mindfulness can have benefits in psoriasis. We are probably only at the bottom of this mountain.
Dr McBurney is a board member of Mindful Medicine. It is a non-profit organisation that focuses on teaching mindfulness to health professionals using retreats. He is founder of McBurney Integrative Neurology and is a clinical assistant professor at the University of New Mexico School of Medicine. Dr. McBurney is a native of Alabama and a graduate of Auburn University and the Emory University School of Medicine. He completed his neurology residency and EEG/Epilepsy fellowship at Walter Reed Army Medical Center. In 2014 he completed the Integrative Medicine Fellowship at the University of Arizona Center for Integrative Medicine.
Dr McBurney has given me so much to think about. I will follow up with part 2 of our discussion that focuses more on the philosophical and life experience aspects of mindfulness once I wrap my head around it.