How does mindfulness meditation change the brain?

What is mindfulness meditation?

Meditation can be defined as a form of mental training that aims to improve an individual’s core psychological capacities, such as attentional and emotional self-regulation. Meditation encompasses a family of complex practices that include mindfulness meditation, mantra meditation, yoga, tai-chi and chi-gong. Of these practices, mindfulness meditation – often described as non-judgemental attention to present-moment experiences – has received most attention in neuroscience research over the past two decades.

mindful
Figure 1. Mindfulness meditation definition by [4].

The positive health benefits of mindfulness meditation

Yet until recently little was known about how a few hours of quiet reflection each week could lead to such an intriguing range of mental and physical effects. Now, as the popularity of mindfulness grows, brain imaging techniques are revealing that this ancient practice can profoundly change the way different regions of the brain communicate with each other – and therefore how we think – permanently. Several research studies concluded that mindfulness mediation acts through the following aspects:

  • Helps people to have more control over their mind: better concentration, memory recall, and focus of attention
  • Stimulates emotional self-control
  • Facilitates a greater self-awareness of the body
  • Improves health and well-being
  • Generaltes change in the perception of the “self”

The strongest scientific evidence to date that meditation has positive health benefits comes from two meta-analyses of meditation research. The first meta-analysis of 47 trials with 3,515 participants found that people participating in mindfulness meditation programs experienced less anxiety, depression, and pain. The second meta-analysis of 163 studies found evidence that meditation practice is associated with reduced negative emotions and neuroticism, and the impact of meditation was comparable to the impact of behavioural treatments and psychotherapy on patients.

Evidence that mindfulness meditation affects the brain

In 2015, an extensive review was published in the top-flight journal Nature Reviews Neuroscience. The review, “The Neuroscience of Mindfulness Meditation,” (i.e. [4]) took a look at the current state of neuroscience research on mindfulness meditation. The authors included Yi-Yuan Tang, a mind-body medicine researcher at the Department of Psychological Sciences, Texas Tech University, who also practices Chinese medicine; Britta Holzel, a neuroscientist and yoga teacher at the Department of Neuroradiology, Technical University of Munich; and Michael Posner, a psychologist at the University of Oregon.

“Although meditation research is still in its infancy, a number of studies have investigated changes in brain activation at rest and during specific tasks that are associated with the practice of, or that follow, training in mindfulness meditation,” write the authors. “There is emerging evidence that mindfulness meditation might cause neuroplastic changes in the structure and function of brain regions involved in regulation of attention, emotion and self-awareness.”

Mindfulness meditation changes brain structure

Over the past decade, numerous neuroimaging studies have investigated changes in brain morphology related to mindfulness meditation. In an attempt to consolidate the findings, one meta-analysis pooled data from 21 neuroimaging studies examining the brains of about 300 experienced meditation practitioners. The study found that eight brain regions were consistently altered in the experienced meditators.

The eight brain regions included the following [1,2,3]:

    • Rostrolateral prefrontal cortex: A region associated with meta-awareness (awareness of how you think), introspection, and processing of complex, abstract information.
    • Sensory cortices and insular cortex: The main cortical hubs for processing of tactile information such touch, pain, conscious proprioception, and body awareness.
    • Hippocampus: A pair of subcortical structures involved in memory formation and facilitating emotional responses.
    • Anterior cingulate cortex and mid-cingulate cortex: Cortical regions involved in self-regulation, emotional regulation, attention, and self-control.
    • Superior longitudinal fasciculus and corpus callosum: Subcortical white matter tracts that communicate within and between brain hemispheres.

The specific ways in which the brain regions changed varied by study (different studies used different neuroimaging measurements), but changes were seen in density of brain tissue, thickness of brain tissue (indicating greater number of neurons, glia, or fibres in a given region), cortical surface area, and white matter fibre density.

nrn3916-f1
Figure 2. Brain regions involved in the components of mindfulness mediation. Schematic view of some of the brain regions involved in attention control (the anterior cingulate cortex and the striatum), emotion regulation (multiple prefrontal regions, limbic regions and the striatum), and self-awareness (the insula, medial prefrontal cortex and posterior cingulate cortex and precuneus). From [4].

The effect of meditation on these particular brain structures appeared to be about “medium” in magnitude—effect sizes that are comparable to the roughly “medium” effects of many other behavioural, educational, and psychological interventions.

Because so many regions were found to be involved in mindfulness meditation, including cerebral cortex, subcortical white and grey matter, brain stem, and cerebellum, Tang, Holzel, and Posner suggested in their review that the effects of meditation might involve large-scale brain networks and multiple aspects of brain function.

Mindfulness meditation alters patterns of brain activity

Brain-imaging studies can reveal not only changes in brain structure, but also changes in brain activation patterns. In their review, Tang, Holzel, and Posner also investigated whether mindfulness meditation exerts its effects via altered activation of brain regions involved with emotional regulation, attention, and self-awareness.

One hypothesis driving emotion regulation is that mindfulness meditation strengthens prefrontal higher order cognitive (thinking) processes that in turn modulate activity in brain regions relevant to emotion processing, such as the amygdala. A number of brain-imaging studies appeared to support this hypothesis.

Buddhist philosophy teaches that identification with the static concept of “self” causes psychological distress. Studies of mindfulness meditators have shown training to be associated with more positive self-representation, higher self-esteem, and higher acceptance of oneself. Such concepts are not easy to capture in neuroscientific studies. However, multiple studies show the insular is strongly activated during meditation. This is thought to represent amplified awareness of the present moment experience“This shift in self-awareness is one of the major active mechanisms of the beneficial effects of mindfulness meditation,” write Tang, Holzel, and Posner.

Examples of alterations

MRI scans show that after an eight-week course of mindfulness practice, the brain’s “fight or flight” center, the amygdala, appeared to shrink. This primal region of the brain, associated with fear and emotion, was involved in the initiation of the body’s response to stress. As the amygdala shrinks, the pre-frontal cortex – associated with higher order brain functions such as awareness, concentration and decision-making – becomes thicker. The “functional connectivity” between these regions – i.e. how often they are activated together – also changes. The connection between the amygdala and the rest of the brain gets weaker, while the connections between areas associated with attention and concentration get stronger [1].

Other studies on expert meditators (i.e. subjects with at least 40,000 hours of mindfulness practice under their belt) discovered that their resting brain looks similar, when scanned, to the way a normal person’s does when he or she is meditating. At this level of expertise, the pre-frontal cortex is no longer bigger than expected. In fact, it’s as if that way of thinking has becomes the default, it is automatic – it doesn’t require any concentration [1].

Future questions for mindfulness meditation research

Despite the enthusiastic reporting of positive findings on the effects of meditation on the brain, it should be pointed out that mindfulness meditation research is a young field, and many studies are yet to be replicated.

There’s still much to discover, especially in terms of what is happening when the brain comprehends the present moment, and what other effects mindfulness might have on people. Research on the technique is still in its infancy, and the imprecision of brain imaging means researchers have to make assumptions about what different regions of the brain are doing.

Author’s note

I’m really excited about the effects of mindfulness. It’s been great to see it move away from being a spiritual thing towards proper science and clinical evidence, as stress is a huge problem and has a huge impact on many people’s health. Being able to take time out and focus our mind is increasingly important.

Perhaps it is the new age, quasi-spiritual connotations of meditation that have so far prevented mindfulness from being hailed as an antidote to our increasingly frantic world. Research is helping overcome this perception, and ten minutes of mindfulness could soon become an accepted, stress-busting part of our daily health regimen, just like going to the gym or brushing our teeth.

References

[1] “What Does Mindfulness Meditation Do to Your Brain?” by Tom Ireland on June 12, 2014 at the Scientific American.

[2] “Neuroscience: This Is How Meditation Changes Your Brain for the Better” by Jessica Stillmen on March 17, 2017 at the Corporation Inc.

[3] “The Neuroscience of Mindfulness Meditation” by Sarah Mckay on February 24, 2017 at the Chopra Center website.

[4] Tang, YY; Hölzel, BK; and Posnerk, MI. “The neuroscience of mindulness meditation”. Nat Rev Neurosci. 2015 Apr;16(4):213-25. doi: 10.1038/nrn3916.

Featured image from Psychology Spot.

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