Meditation Produces Lasting Changes in Brain Processing

A number of previous studies have suggested that meditation training improves practitioners’ emotional regulation. While neuroimaging studies have found that meditation training appeared to decrease activation of the amygdala — a structure at the base of the brain that is known to have a role in processing memory and emotion — those changes were only observed while study participants were meditating.  Gaelle Desbordes, from Massachusetts General Hospital (Massachusetts, USA), and colleagues investigated whether meditation training could also produce a generalized reduction in amygdala response to emotional stimuli, even when the practitioner was not meditating.  Participants were enrolled in a larger investigation into the effects of two forms of meditation – mindful meditation and compassionate meditation, based at Emory University (Georgia, USA).  Healthy adults with no experience meditating participated in 8-week courses in either meditative approach; a control group participated in an 8-week health education course. Within three weeks before beginning and three weeks after completing the training, 12 participants from each group were given brain scans, performed as the subjects viewed a series of 216 different images — 108 per session — of people in situations with either positive, negative or neutral emotional content. Meditation was not mentioned in pre-imaging instructions to participants, and investigators confirmed afterwards that the volunteers had not meditated while in the scanner. Participants also completed assessments of symptoms of depression and anxiety before and after the training programs.  In the mindful meditation group, the after-training brain scans showed a decrease in activation in the right amygdala in response to all images, supporting the hypothesis that meditation can improve emotional stability and response to stress. In the compassion meditation group, right amygdala activity also decreased in response to positive or neutral images. But among those who reported practicing compassion meditation most frequently outside of the training sessions, right amygdala activity tended to increase in response to negative images — all of which depicted some form of human suffering. No significant changes were seen in the control group or in the left amygdala of any study participants. The study authors observe that: “these results are consistent with the overarching hypothesis that meditation may result in enduring, beneficial changes in brain function, especially in the area of emotional processing.”