Mindfulness and your brain

I am often asked for advice from undergraduates about what career path they should take after their degree, and am always delighted when they express an interest in neuroscience. I recently probed this interest with a student. He told me he saw neuroscience and study of the human brain – what Neil Carlson (1) described as “the last frontier in this world and perhaps the greatest” – as the future, potentially the most exciting and rewarding field of study one could pursue. As the discussion unfolded, I was slightly less enthused when it unfolded through the conversation that he saw mindfulness as “more of a 2016 thing”.

When the ringing in my ears stopped, it did make me wonder about the wider perception of mindfulness, and the fact we have become inundated with it as a panacea, a celebrity-endorsed cure for all ailments. We have developed an interesting relationship with mindfulness recently and maybe we might be getting too much of a good thing. The risk of course is that we become weary of one of the greatest tools we have in the Psychology toolkit, jaded with its ever-presence, its unhealthy and undeserved proclamation as an elixir to remedy everything our minds have to throw at us.

Part of the reason why people may be becoming fed up of hearing about it, and why everyone is recommending it to everyone else, may be misconceptions about what it is. Among them are the impression that it is like positive thinking, is about getting rid of negative thoughts, or is about trying to relax, none of which accurately reflect its main idea. There are many definitions of what it is, but the central tenet is that mindfulness involves staying in the present moment, without judgement. A central focus of the practice is being fully present, without worrying about the past or thinking about the future – “paying attention to relevant aspects of experience in a non-judgmental manner” (2).

The science of mindfulness and how it works is becoming clear, and its benefits in the correct context are well-established, both in the short term and long term. It is routinely and appropriately recommended by Mental Health Professionals for a variety of reasons. It is important to note, however, that there are times when mindfulness is contraindicated, for example, with active addictions or trauma. What has been less clear until recently, however, are the brain mechanisms by which mindfulness works, and how it affects both the functioning and structure of the brain. Recent research has shown a myriad of brain areas are involved in mindfulness, and its long term practice affects both brain function and structure.

Changes in brain function

When we engage in mindfulness, many areas of the neocortex become activated. The neocortex comprises the convoluted and creviced external layers that cover the cerebral hemispheres (the word neocortex is derived from the Latin for new bark or new rind, reflecting the relatively recent evolutionary appearance of this brain structure). In humans it comprises the majority of our brains, and is responsible for a huge range of the complex functions that we possess like social control, conscious thought, abstract thinking and language. In humans and other primates, the convoluted and folded nature of the surface of the neocortex increases its area considerably. It is sometimes referred to as grey matter. Comprising six layers in total, each of the layers are interconnected allowing for complex neural processing. When a person engages in mindfulness, the bottom two layers of the neocortex in particular become activated. This has a significant effect on a range of brain structures (see below).

Long term practice of mindfulness has a significant effect on our brain’s tendency to select activation/engagement behaviours over inhibition/withdrawal behaviours. This is the result of a general shift towards activation in the left frontal and pre-frontal areas of the neocortex compared to the right. This left versus right frontal system, which controls a range of behaviours, is known as the Behavioural Inhibition System – Behavioural Activation System (BIS-BAS). The BIS-BAS balances behavioural activation with behavioural avoidance, leading to a tendency towards behaviours categorised as extraverted (BAS) or introverted and neurotic (BIS). By shifting activation to the left, mindfulness in the long term leads to a greater tendency to engage the activation branch of the BIS-BAS. As such, long term mindfulness fosters a tendency towards behavioural activation, leading a person towards social contact and support and a potential solution to problems they may be experiencing, and away from introversion, rumination and avoidance (3).

This has a number of further benefits. When we experience anxiety, there is a decrease in blood flow (and by default activity) in the left prefrontal areas of the cortex and an increase to the right; mindfulness can help re-activate the left in order to counteract anxiety. In addition, emotional arousal can be managed, in that the limbic system becomes downregulated when the left prefrontal cortex is engaged and activated. The limbic system, sometimes referred to as the mammalian brain, is a collection of brain areas which play a central role in the regulation of emotion, whose activity is much quicker but less nuanced than the neocortex (the amygdala in the limbic system, for example, controls the fight or flight response – an outstandingly swift but blunt mechanism designed to escape or fight a threat before conscious awareness). Downregulating the limbic system by engaging the left prefrontal cortex – the means by which humans can manage emotions like anxiety and fear – is thereby facilitated by long term mindfulness.

Changes in brain structure

With long term mindfulness practice, the concentration and thickness of the neocortex increases in a huge range of brain areas. Among these areas are those involved in emotional regulation, learning, memory, self-referencing and ability to take perspectives³. They include areas like the hippocampus (memory), insular cortex (empathy, pain, laughter, crying), pre-frontal cortex (executive functions like attention, language, social control, inhibiting responses, planning, organising), the posterior cingulate gyrus (emotion, memory), the temporo-parietal junction (attention, empathy, language) and the cerebellum (posture, balance, coordination, speech).

Further to this, there is an enhanced integration of a number of brain structures, which allows for greater communication between brain areas, and greater activation of brain networks. In general, the increased integration is most pronounced in areas associated with the limbic system (4). This enhanced neural integration through the practice of mindfulness again leads to a greater control over amygdala over-reactions, thereby reducing the fight or flight response and anxiety. Achieved through the process of neuroplasticity, it also plays a role in our ability to be present in the moment, as well as increasing our ability to be compassionate with others (5).

In summary, neuroscience can tell us a lot about how Mindfulness works…

• Long term practice of mindfulness confers a number of benefits through changes in the way the brain functions as well as the way it is structured
• It activates the left frontal and prefrontal neocortex, thereby enhancing behavioural activation and extraversion
• Through this same mechanism it can directly counteract anxiety
• It also increases the integration of a number of brain areas which are key to emotional regulation. Specifically, through increased connectivity, it allows the prefrontal cortex to better regulate the activity of the amygdala, reducing the tendency towards anxiety and over-reactions
• Changes in the structure can be seen in a range of brain areas linked to the limbic system

References

1. Carlson NR. Physiology of behavior. Eleventh ed. Boston: Pearson; 2013. 748 p.
2. Ludwig DS. Mindfulness in Medicine. JAMA. 2008 Sep 17;300(11):1350.
3. Siegel DJ. The developing mind: how relationships and the brain interact to shape who we are. 2015.
4. Prinsloo S. A Review of: “Being a Brain-Wise Therapist: A Practical Guide to Interpersonal Neurobiology. Bonnie Badenoch”: Norton, New York, New York, 2008, 384 pages, ISBN: 978-0393705546. J Neurother. 2011 Oct;15(4):399–400.
5. Hölzel BK, Carmody J, Vangel M, Congleton C, Yerramsetti SM, Gard T, et al. Mindfulness practice leads to increases in regional brain gray matter density. Psychiatry Res Neuroimaging. 2011 Jan;191(1):36–43.