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Tuesday, November 13, 2012

Meditation has lasting effects

The changes that take place in the brain during meditation -- reduced activity in the amygdala, which regulates stress response, for instance -- continue after a meditation session ends, according to a research study published this month in Frontiers in Neuroscience.

Researchers at Massachusetts General, Boston College, and other participating institutions also found differences in the brain activity of those who practiced mindfulness-awareness meditation and those who did compassion practices during meditation sessions.

“The two different types of meditation training our study participants completed yielded some differences in the response of the amygdala – a part of the brain known for decades to be important for emotion – to images with emotional content,” says GaĆ«lle Desbordes, PhD, 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, corresponding author of the report. “This is the first time that meditation training has been shown to affect emotional processing in the brain outside of a meditative state.”

Participants in three groups took part in eight-week trainings in either mindfulness-awareness meditation, compassion meditation, or general health classes. They had brain-imaging tests before and after the programs as they viewed photographs.

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,” Desbordes explains. “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.”