A Buddhist Psychological Model of Mindfulness

Recently, my colleague Dr. Mark Lau and myself wrote a short post on the UCSD Center for Mindfulness Blog. It describes, in brief, a Buddhist psychological model of how mindfulness exerts its clinical effects, based on the paper mentioned in my last post.  You can read the blog post here.

How Does Mindfulness Work?

Interest in mindfulness in the clinical setting continues to grow.  My colleagues, Dr. Mark Lau and Brandilyn Willett, and I have recently published a paper in the journal Mindfulness that proposes a detailed model to explain the mechanisms by which mindfulness exerts its clinical effects.  You can view an online fulltext version of the paper here.

The Neurobiology of Mindfulness

There have been many exciting advances in the last few years in our understanding of how mindfulness meditation affects both the structure and function of the brain.  I want to tell you about 4 studies to explain why mindfulness can be a powerful tool in the treatment of a number of psychiatric disorders.

Structural Brain Changes

Structural changes in the brain can occur as the result of meditation, according a study by Sara Lazar and her group at the Psychiatric Neuroimaging Research Program at Massachusetts General Hospital.  Lazar took a group of experienced mindfulness practitioners and a matched control group that had no meditation experience, and they measured the thickness of their cerebral cortex.  They found that the parts of the brain involved in self-reflection and empathy were significantly thicker in the meditators than in controls.

Increased cortical thickness as a result of meditation

Increased cortical thickness as a result of meditation

In particular, Lazar identified 2 cortical areas where differences in thickness between meditators and non-meditators were particularly striking.  These were the right anterior insula (labeled number 1 in the figure above), which is involved in awareness of internal states, and Brodmann area 9/10 (labeled number 2 in the figure above), which is involved in the integration of emotion and cognition.  The clinical implication of cortical thickening in these specific brain areas is that increased awareness of internal sensations and improved integration of emotion and cognition may improve how stressful events are handled. They also found that the typical age-related decreases in thickness in Brodman 9/10 area that we see in most brains did not occur in the brians of the meditators!

Functional Brain Changes

The next study I want to tell you about was done by Richard Davidson and his team at the Laboratory for Affective Neuroscience at the University of Wisconsin.  To understand this study, I need to first give you some background on how the prefrontal cortex (PFC) is involved in emotion regulation.  Each of us tends to have either greater left PFC activity or greater right PFC activity.  This is known as asymmetrical prefrontal cortical activation, and the balance between left and right prefrontal cortex is key in emotion regulation.

Studies have shown that people with more left-sided activation tend to be more approach and reward oriented and emotionally positive, whereas people with more right-sided activation tend toward more avoidant and withdrawn and have more negative emotions such as anger, anxiety and depression.  This asymmetry is eve npresent at birth and has been found to predict the length of time that it takes ionfants to cry after they are separated from the mothers!  Perhaps not surprisingly, in people suffering from depression the finely tuned balance between left and right activation is shifted towards more right sided activation.

Increase in Left-sided PFC activation as a result of mindfulness practice

Increase in Left-sided PFC activation as a result of mindfulness practice

What Davidson wanted to know was whether mindfulness practice would shift the brain of the practitioners to having more left-sided prefrontal activation.  Davidson found that 8 weeks of mindfulness practice increased left-sided prefrontal activation both at baseline and in response to emotional stimuli. The figure above shows the increase in left sided activation with negative affective stimuli in the meditation group, before the meditation course (Time 1) and 4 months after the course ended (Time 3).  This is consistent with other research showing that more leftsided prefrontal activation is associated with more adaptive responses to negative or stressful life events.  Davidson’s work was the first to show that meditation could bring about this effect.  They also observed that this shift towards increased left sided activation was associated with significant reductions in anxiety and negative affect in the meditation group.

I’d like to point out that this study also demonstrated that meditation can affect brain function in a sustained manner. That is, brain changes induced by mindfulness practice, like the shift to left sided activation, continued to be present in the brain between periods of mindfulness practice.

There is another way that increased levels of mindfulness change brain function. Several neurobiological studies have shown that during affect labeling, that is, when we use words to identify the emotion we are feeling, the prefrontal cortex becomes active and downregulates the activity of the amygdala, a region commonly associated with negative affective states. Interestingly, in people suffering from depression, the prefrontal cortex is less able to moderate the activity of the amygdala.

This figure above is from a study done by Creswell and his group at UCLA.  They showed that in people with greater mindfulness, the effect of affect labeling is increased, resulting in a greater downregulation of the amygdala (as shown in the figure above) than in those with lower mindfulness.  In other words, participants who had greater mindfulness scores at baseline were better able to regulate negative emotions than those with lower mindfulness scores.

Clinical Applications

Mindfulness Based Cognitive Therapy has been shown to decrease depressive relapse rates by almost 50% in the year after MBCT treatmentbra!  Let’s look at how the functioinal brain  changes we have just reviewed might account for this result.

People suffering with depression have an impaired ability to regulate negative mood.   Johnstone’s research into brain changes that occur with depression highlighted two changes:  first, there is counterproductive activation of the right prefrontal cortex, (depressed individuals have the shift to right sided prefrontal cortical activation that we discussed earlier) and secondly, in depression there is upregulation of the amygdala by the left ventromedial prefrontal cortex, rather than the downregulation seen in healthy individuals.  So in depression we see a shift to overall right sided prefrontal cortical activation rather than left and upregulation rather than downregulation of the amygdala.
So one of the reasons that mindfulness can be such a powerful tool in treating depression is because it has the potential to reverse the neurobiological changes seen in depression.  Mindfulness can shift a more right sided activation to a more left sided activation, and strengthen the functional connectivity between the PFC and the amygdala, allowing the left PFC to more effectively downregulate emotional responses in the amygdala.

Mindfulness Matters - a new blog and website

Welcome to Mindfulness Matters! This website is a place for patients, clinicians and others to learn about and discuss the connections between mindfulness and mental health.

I will be writing about the latest research in mindfulness and neurobiology, as well as sharing related insights from both my clinical and personal practice with mindfulness.

For an overview about what mindfulness is and how it relates to mental health, you can read my article What is Mindfulness?

For more information about my clinical and research activities, you can read my bio.

Please contact me with specific questions or topics you would like to know more about and I will try to address them in the blog.

Thank you for visiting Mindfulness Matters!