Practising mindfulness – spending time paying attention to your current mental experiences in a non-judgmental way – has been associated with many beneficial outcomes, including reduced anxiety and improved decision making (although note, there could be some adverse effects for some people). What are the neural correlates of these effects? A new systematic review in Brain and Cognition has looked at all studies published prior to July this year that investigated brain changes associated with eight weeks of Mindfulness Based Stress Reduction or Mindfulness Based Cognitive Therapy. The combined results suggest that a short course of secular mindfulness training leads to multiple brain changes similar in nature to those seen in people who have practised religious or spiritual meditation for a lifetime.
Rinske Gotink and her colleagues found 30 relevant studies that used MRI or fMRI brain imaging to look at the effects of mindfulness training on brain structure and function, including 13 randomly controlled trials. Associated brain changes, in terms of activity levels and volume and connectivity changes, have been reported in the prefrontal cortex (a region associated with conscious decision making and emotional regulation and other functions), the insula (which represents internal body states among other things), the cingulate cortex (decision making), the hippocampus (memory) and the amygdala (emotion). Based on what we know about the function of these brain regions, Gotink’s team said these changes appear to be consistent with the idea that mindfulness helps your brain regulate your emotions.
Most of these brain changes linked with brief mindfulness training are similar to the brain changes associated with long-term spiritual or religious meditation, although the finding for the amygdala (reduced activity and volume after mindfulness) has not usually been observed in long-term meditators. The researchers speculated this may be because meditating monks and nuns, who have featured in much of the meditation research, started out with little stress – their amygdalae were “calm” already. In contrast, students of mindfulness are more likely to start out stressed and to reap a calming benefit from the training, which is perhaps what is reflected in the changes to their amygdalae structure and function.
If this sounds highly speculative, it is. This study provides a useful roundup of all that we know so far about mindfulness-based brain changes, but the reality, as the researchers acknowledge, is that the existing evidence base reflects a mixed bag of methods and approaches of variable quality and with a publication bias toward positive results quite likely. Moreover, the meaning and size of the brain changes is open to interpretation, and the precise cause of them is not clear because mindfulness training is multifaceted and includes non-specific components such as the simple act of meeting up with other people in a sociable setting.