thoughts change structure and function of brain

[Michael_E]

Scans of Monks' Brains
Show Meditation Alters
Structure, Functioning

All of the Dalai Lama's guests peered intently at the brain scan
projected onto screens at either end of the room, but what different
guests they were.

On one side sat five neuroscientists, united in their belief that
physical processes in the brain can explain all the wonders of the
mind, without appeal to anything spiritual or nonphysical.

Facing them sat dozens of Tibetan Buddhist monks in burgundy-and-
saffron robes, convinced that one round-faced young man in their
midst is the reincarnation of one of the Dalai Lama's late teachers,
that another is the reincarnation of a 12th-century monk, and that
the entity we call "mind" is not, as neuroscience says, just a
manifestation of the brain.

It was not, in other words, your typical science meeting.

But although the Buddhists and scientists who met for five days
last month in the Dalai Lama's home in Dharamsala, India, had
different views on the little matters of reincarnation and the
relationship of mind to brain, they set them aside in the interest
of a shared goal. They had come together in the shadows of the
Himalayas to discuss one of the hottest topics in brain science:
neuroplasticity.

The term refers to the brain's recently discovered ability to change
its structure and function, in particular by expanding or
strengthening circuits that are used and by shrinking or weakening
those that are rarely engaged. In its short history, the science of
neuroplasticity has mostly documented brain changes that reflect
physical experience and input from the outside world. In pianists
who play many arpeggios, for instance, brain regions that control
the index finger and middle finger become fused, apparently because
when one finger hits a key in one of these fast-tempo movements, the
other does so almost simultaneously, fooling the brain into thinking
the two fingers are one. As a result of the fused brain regions, the
pianist can no longer move those fingers independently of one
another.

Lately, however, scientists have begun to wonder whether the brain
can change in response to purely internal, mental signals. That's
where the Buddhists come in. Their centuries-old tradition of
meditation offers a real-life experiment in the power of those will-
o'-the-wisps, thoughts, to alter the physical matter of the brain.

"Of all the concepts in modern neuroscience, it is neuroplasticity
that has the greatest potential for meaningful interaction with
Buddhism," says neuroscientist Richard Davidson of the University of
Wisconsin, Madison. The Dalai Lama agreed, and he encouraged monks
to donate (temporarily) their brains to science.

The result was the scans that Prof. Davidson projected in
Dharamsala. They compared brain activity in volunteers who were
novice meditators to that of Buddhist monks who had spent more than
10,000 hours in meditation. The task was to practice "compassion"
meditation, generating a feeling of loving kindness toward all
beings.

"We tried to generate a mental state in which compassion permeates
the whole mind with no other thoughts," says Matthieu Ricard, a
Buddhist monk at Shechen Monastery in Katmandu, Nepal, who holds a
Ph.D. in genetics.

In a striking difference between novices and monks, the latter
showed a dramatic increase in high-frequency brain activity called
gamma waves during compassion meditation. Thought to be the
signature of neuronal activity that knits together far-flung brain
circuits, gamma waves underlie higher mental activity such as
consciousness. The novice meditators "showed a slight increase in
gamma activity, but most monks showed extremely large increases of a
sort that has never been reported before in the neuroscience
literature," says Prof. Davidson, suggesting that mental training
can bring the brain to a greater level of consciousness.

Using the brain scan called functional magnetic resonance imaging,
the scientists pinpointed regions that were active during compassion
meditation. In almost every case, the enhanced activity was greater
in the monks' brains than the novices'. Activity in the left
prefrontal cortex (the seat of positive emotions such as happiness)
swamped activity in the right prefrontal (site of negative emotions
and anxiety), something never before seen from purely mental
activity. A sprawling circuit that switches on at the sight of
suffering also showed greater activity in the monks. So did regions
responsible for planned movement, as if the monks' brains were
itching to go to the aid of those in distress.

"It feels like a total readiness to act, to help," recalled Mr.
Ricard.

The study will be published next week in Proceedings of the
National Academy of Sciences. "We can't rule out the possibility
that there was a pre-existing difference in brain function between
monks and novices," says Prof. Davidson, "but the fact that monks
with the most hours of meditation showed the greatest brain changes
gives us confidence that the changes are actually produced by mental
training."

That opens up the tantalizing possibility that the brain, like the
rest of the body, can be altered intentionally. Just as aerobics
sculpt the muscles, so mental training sculpts the gray matter in
ways scientists are only beginning to fathom.


See also: mindandlife.org