A new study has found that participating in an 8-week meditation training program can have measurable effects on how the brain functions even when someone is not actively meditating. In their report in the November issue of Frontiers in Human Neuroscience, investigators at Massachusetts General Hospital and Boston University also found differences in those effects based on the specific type of meditation practiced.

“This is the first time that meditation training has been shown to affect emotional processing in the brain outside of a meditative state,” says Gaëlle Desbordes, PhD, corresponding author of the report. Additionally, the two different types of meditation training yielded some differences in the response of the amygdala – a part of the brain known for decades to be important for emotion. One type appeared to reduce states of depression.

Several previous studies have supported the hypothesis that meditation training improves practitioners’ emotional regulation. While neuro-imaging studies have found that meditation training appeared to decrease activation of the amygdala, those changes were only observed while study participants were meditating. The current study was designed to test the hypothesis that meditation training could also produce a generalized reduction in amygdala.

Healthy adults with no experience meditating participated in 8-week courses in either mindful attention meditation – the most commonly studied form that focuses on developing attention and awareness of breathing, thoughts and emotions – and compassion meditation, a less-studied form that includes methods designed to develop loving kindness and compassion for oneself and for others. A control group participated in an 8-week course in health education.

Within three weeks before beginning and three weeks after completing the training, 12 participants from each group traveled to Boston for magnetic resonance brain imaging (fMRI).  Brain scans were performed as the volunteers 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.

In the mindful attention 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.

“We think these two forms of meditation cultivate different aspects of mind,” explains Desbordes ,a research fellow at the Athinoula A. Martinos Center for Biomedical Imaging at MGH and at the BU Center for Computational Neuroscience and Neural Technology. “Since compassion meditation is designed to enhance compassionate feelings, it makes sense that it could increase amygdala response to seeing people suffer. Increased amygdala activation was also correlated with decreased depression scores in the compassion meditation group, which suggests that having more compassion towards others may also be beneficial for oneself. Overall, 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.”

Source: Massachusetts General Hospital