Sex is in the brain, says new research

Mar 02, 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."

More information: The results appeared in the Jan. 23 issue of the journal Neuroscience.

Source: Stanford University Medical Center

Explore further: How nerve cells communicate with each other over long distances

add to favorites email to friend print save as pdf

Related Stories

FIXD tells car drivers via smartphone what is wrong

3 hours ago

A key source of anxiety while driving solo, when even a bothersome back-seat driver's comments would have made you listen: the "check engine" light is on but you do not feel, smell or see anything wrong. ...

Team pioneers strategy for creating new materials

5 hours ago

Making something new is never easy. Scientists constantly theorize about new materials, but when the material is manufactured it doesn't always work as expected. To create a new strategy for designing materials, ...

Shell files new plan to drill in Arctic

5 hours ago

Royal Dutch Shell has submitted a new plan for drilling in the Arctic offshore Alaska, more than one year after halting its program following several embarrassing mishaps.

Aging Africa

5 hours ago

In the September issue of GSA Today, Paul Bierman of the University of Vermont–Burlington and colleagues present a cosmogenic view of erosion, relief generation, and the age of faulting in southernmost Africa ...

Recommended for you

Why your favourite song takes you down memory lane

Aug 28, 2014

Music triggers different functions of the brain, which helps explain why listening to a song you like might be enjoyable but a favourite song may plunge you into nostalgia, scientists said on Thursday.

Transcranial Magnetic Stimulation of brain boosts memory

Aug 28, 2014

Stimulating a particular region in the brain via non-invasive delivery of electrical current using magnetic pulses, called Transcranial Magnetic Stimulation, improves memory, reports a new Northwestern Medicine ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

el_gramador
not rated yet Mar 02, 2009
Answer: Simply tell them to relax. Spa, pedicure, massage, the works. Seperate them from themselves and let them become less self-conscious.
superhuman
not rated yet Mar 03, 2009
hypoactive sexual desire disorder, or HSDD


I am curious how many of those women actually consider it the problem themselves as opposed to their partner inducing them to seek help.

In reality it should be considered natural and healthy that some females loose interest in sex with the same partner after first intense 1-2 years. From biological perspective for females it makes more sense to switch partners every few years to produce offspring with more varied genotype which will maximize their chances of success.

Some women do enjoy sex enough to continue sexual relations even after the first intense love high wares out, but others who are more inhibited need this high to pass their psychological barriers and without it their internal conflict will result in them losing interest.

Both biological and social factors play a role here, as I said from biology POV it makes more sense to switch partners unless the current one is seen as by far the best possible choice. As for social factors (which are also an indirect result of biology) the most important fact is that women sexuality is often negatively perceived by society and so I suspect many girls construct their own self image on the basis of rejection of what they see as promiscuity and instead learn to suppress their sexual desires. The intense natural high of a new love easily steamrolls any such barriers but as it wanes out internal conflicts will intensify and it seems sexuality eventually loses this fight.
All these psychological mechanisms are subconscious and women have no control over them at all.

This theory fits well with the results presented in the article since the activation can be interpreted as suppression of erotic memories which could lead to arousal by self-image circuit. Unfortunately as is always the case with such studies this is just a hypothesis and I can't see how it can be either proven or disproven scientifically.

The best solution in my opinion is to adapt social norms to better reflect our biology and accept that many people are more happy with short 1-4 years relationships then with monogamy. The biggest problem with such a society is rising kids though. Personally I believe we should develop a more collective model of parenting something more like what we had during the majority of our evolution as social mammals.