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Sex
Is In The Brain, Says New Research From Stanford
MedicalNewsToday.com,
March 4, 2009. More than 40 percent of women ages 18-59
experience sexual dysfunction, with lack of sexual interest -
hypoactive sexual desire
disorder, or HSDD - being the most commonly reported
complaint, according to medical
researchers. While some question the validity of this
diagnosis,
a multidisciplinary team from
the Stanford University School
of Medicine is devoted to objective investigation of such
problems.
Here
is a quick briefing on new research on this problem from Bruce
Arnow, PhD, professor
of psychiatry and behavioral sciences, and Leah Millheiser, MD,
clinical assistant professor
of obstetrics and gynecology and director of the
Female Sexual Medicine Program at
Stanford Hospital & Clinics.
The
question: What role does the brain play in some women's lack
of sexual
desire?
Background:
Studies of factors affecting sexual performance have largely
focused on men,
and on physiology of the body rather than the brain. But the
brain, rather than peripheral
organs, may play the key role in female sexual
dysfunction.
The
study: The trial is the first to compare brain-activation
patterns of females who have
HSDD with those who don't. Sixteen women diagnosed with HSDD, along with 20 normal
control subjects, took part in the study. All subjects
identified themselves as heterosexual.
The
experiment: Subjects were shown erotic video segments
interspersed among footage of
female sporting events. These segments were separated by
intervening tranquil sequences of
such subjects as flowers, mountains or ocean waves
to bring the women's brains to a resting
state between more-active segments. Their
brain activity was monitored by functional
magnetic-resonance imaging, which
allows the activity of different brain regions to be
assessed in real time. The women
also reported their subjective levels of sexual arousal
throughout the viewing. Meanwhile, the researchers also collected objective measurements
of the
women's level of genital arousal.
The
findings: Activity patterns throughout most of the brain were
more or less identical among
the HSDD and normal groups, but with a few notable
exceptions. There was a bigger jump in
relative activity in three brain areas of HSDD
women -
the
medial frontal gyrus, right inferior
frontal gyrus and
bilateral putamen - compared with the control subjects when shown the
erotic clips. In another
brain area - the bilateral entorhinal cortex - the opposite effect
occurred.
This finding establishes specific locations in the brain where activity in women with
HSDD is altered in comparison with women not reporting this problem.
Discussion:
Two of the brain areas where the HSDD women had increased
activity (the
medial frontal gyrus and right inferior frontal gyrus) have been
previously associated with,
respectively, heightened attention to one's own and
others' mental states, and suppression of
one's emotional response. The research suggests
that increased attention to one's own
responses to erotic stimuli plays some
part in the sexual dysfunction. The increased activation
in the entorhinal cortex
observed in the control subjects may correlate with an improved
ability among women with
no sexual dysfunction, compared with HSDD women, to lay down
emotional memories related to sexual events.
Caveats:
Correlation is not cause and effect. The study could be
showing how paying too
much attention causes inhibition of sexual desire - or how the
lack of desire in a sexually
charged situation causes heightened
self-consciousness.
Bottom
line: "The results of this study provide yet another valuable
tool for understanding the
complexity of female sexual function as it relates to
desire," Millheiser said. "The next step is
to translate this information into the
clinical realm, specifically as it relates to cognitive and
pharmacotherapeutic
approaches."
Published:
The results appeared in the Jan. 23 issue of the journal
Neuroscience.
Notes:
Stanford
University Medical Center integrates research, medical
education and patient care
at its three institutions - Stanford University School of
Medicine, Stanford Hospital & Clinics
and Lucile Packard Children's Hospital at
Stanford. For more information, please visit the
Web site of the medical center's
Office of Communication & Public Affairs at
http://mednews.stanford.edu.
Source:
Bruce Goldman
Stanford
University Medical Center
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