Contract
bridge enhances the immune system, according to a preliminary
study by researchers at UC Berkeley
08
Nov 2000
By
Robert Sanders, Media Relations
EMBARGOED
FOR RELEASE UNTIL 8 A.M. CST WEDNESDAY, NOV. 8, TO COINCIDE
WITH POSTER SESSION AT ANNUAL MEETING OF THE SOCIETY FOR NEUROSCIENCE
New Orleans
-In a presentation at this week's meeting of the Society for
Neuroscience, University of California, Berkeley, biologist
Marian Cleeves Diamond will describe an experiment showing
that contract bridge players have increased numbers of immune
cells after a game of bridge.
Based
on her previous work, and that of others, Diamond interprets
the findings as strong evidence that an area of the brain
involved in playing bridge stimulates the immune system, in
particular the thymus gland that produces white blood cells
called T cells, or T lymphocytes.
If her
study is borne out, this would be the first time a specific
area of the cortex - in this case, part of the frontal lobe
of the brain - has been linked with the immune system.
"People
are aware that voluntary activities like positive thinking
and prayer work to keep us healthy, but no one has had a mechanism,"
said Diamond, a professor of integrative biology in the College
of Letters & Science at UC Berkeley. "These data, though preliminary,
show that brain activity affects the immune system, and support
the possibility of us learning to voluntarily control the
level of white blood cells to help combat disease and other
illnesses."
A poster
describing the study will be displayed Wednesday, Nov. 8,
during the Nov. 4-9 meeting in New Orleans of the Society
for Neuroscience.
The experiment
is the culmination of more than 15 years of work on rat and
mouse brains by Diamond and her colleagues in search of a
cortical area connected to the immune system. It's also a
poignant tribute to her sister, who died when Diamond was
19 of the autoimmune disease systemic lupus erythematosus.
"Someday,
I thought, I will find something that correlates with what
killed her," said Diamond, 73. "But I'm a neuroscientist,
not an immunologist, so I had to touch the immune system through
the brain."
Diamond
chose to study bridge players from an Orinda, Calif., women's
bridge club because bridge is a game likely to stimulate an
area of the brain - the dorsolateral cortex - that she suspected
influences the immune system. She selected women as subjects
because most of her laboratory experiments have involved immune
compromised female mice.
Diamond
and graduate student Jean Weidner divided the 12 women, all
in their 70s and 80s, into three groups, and had each group
play a one-and-a-half hour bridge set. Weidner, a former phlebotomist,
drew blood samples before and after the sets, and delivered
them to immunology research associates Peter Schow and Stan
Grell to measure the numbers of immune cells.
Only the
levels of CD-4 positive T cells changed in the 12 subjects.
In two of the groups, levels increased significantly. In the
third group, T cell levels increased only slightly, not enough
to be statistically significant.
T cells
are white blood cells produced by the thymus gland and sent
out to patrol the body in search of viruses and other invaders.
T cells that sport a surface marker called CD-4 are "helper"
cells that regulate the activity of antibody-producing B cells
and of other T cells.
In 1985,
Diamond and her students first focused on the dorsolateral
cortex - a brain area behind the forehead and a little to
the side - after comparing the brains of normal mice with
immune deficient mice, called nude mice. The only brain difference
they could measure was in the dorsolateral cortex, which was
thinner in nude mice on both the right and left sides of the
brain. The cortex, the outer layer of the brain, deals with
higher order functions; the dorsolateral cortex is involved
with such things as working memory, planning ahead and initiative.
Because
nude mice have deficiencies in their thymus gland, in the
early 1990s Diamond and then doctoral student Gary Gaufo,
who has since obtained his PhD, transplanted normal mouse
thymus glands into immune compromised mice. Surprisingly,
all of the mice developed normal levels of T cells and also
showed thickening of the dorsolateral cortex.
Given the
apparent connection between the thymus gland - the source
of T cells - and the dorsolateral cortex, she looked around
for a way to test the connection in humans. She discovered
a 1990 paper by a team of researchers from the National Institute
of Mental Health reporting that the dorsolateral prefrontal
cortex is stimulated by a card sorting task used for psychiatric
analysis. The authors had used SPECT (single photon emission
computed tomography) to determine the parts of the brain that
were active during the task, comparing schizophrenics with
normal subjects.
While that
task, the so-called Wisconsin Card Sorting Task, is suitable
for psychiatric tests, she decided that contract bridge would
be a perfect substitute to use with normal subjects.
"Contract
bridge was ideal for what we were after," she said. "It is
the closest activity to a challenging card sorting task that
also contains multiple factors that should stimulate the dorsolateral
cortex. Bridge players plan ahead, they use working memory,
they deal with sequencing, initiation and numerous other higher
order functions with which the dorsolateral cortex is involved."
Luckily,
her old college roommate, Marian Everett, was a member of
a golfing and bridge club in Orinda, so Diamond approached
her about finding a group of 12 players.
"They were
so willing to be part of the experiment," Diamond said, that
she had no problem getting enough volunteers.
In the
future, as a possible follow-up study, Diamond suggests using
a functional nuclear magnetic resonance machine to see if
the dorsolateral cortex actually does show greater activity
during bridge playing than during rest.
Because
the brain's cortex is under voluntary control, she hopes her
findings lead to ways to educate the brain to improve health.
"If we
could find out how to regulate our immune system voluntarily
through the brain's cortex, I would feel extremely happy,"
Diamond said.
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