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 (MGH),
Boston University (BU), and several other research centers also
found differences in those effects based on the specific type of
meditation practiced.
Study participants who completed an
8-week meditation training course had reduced activity in the right
amygdala (highlighted structure) in response to emotional images,
even when not meditating. (Gaëlle Desbordes, PhD, Martinos Center
for Biomedical Imaging, Mass. General Hospital)
"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 Gaëlle 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."
Several previous studies have supported
the hypothesis that meditation training improves practitioners'
emotional regulation. While neuroimaging 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 response to emotional stimuli, measurable by functional
magnetic resonance imaging (fMRI).
Participants had enrolled in a larger
investigation into the effects of two forms of meditation, based at
Emory University in Atlanta. 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 health education course.
Within three weeks before beginning and
three weeks after completing the training, 12 participants from each
group traveled to Boston for fMRI brain imaging at the Martinos
Center's state-of-the-art imaging facilities.
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. Participants also completed
assessments of symptoms of depression and anxiety before and after
the training programs.
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."
Eric Schwartz, PhD, of the BU Department
of Electrical and Computer Engineering and Center for Computational
Neuroscience and Neural Technology, is senior author of the
Frontiers in Human Neuroscience report. Additional co-authors are
Lobsang T. Negi, PhD, and Thaddeus Pace, PhD, Emory University; Alan
Wallace, PhD, Santa Barbara Institute for Consciousness Studies; and
Charles Raison, MD, University of Arizona College of Medicine. The
study was supported by grants from the National Center for
Complementary and Alternative Medicine, including an American
Recovery and Reinvestment Act grant to Boston University.
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