Orgasm is literally a mind-blowing experience for a woman, scientists revealed on Monday.
Much of her brain shuts down when she reaches a sexual climax, including areas that deal with emotion.
The
discovery was made during a bizarre set of experiments in the
Netherlands in which couples were asked to stimulate each other while
undergoing brain scans.
It seems to explode the myth that while men switch off during sex, the part of women that is most turned on is in their heads.
By looking at the brain scans, researchers had no trouble telling when women were "faking it".
The
brains of volunteers who were asked to simulate orgasm after a period
of stimulation remained fully active and in conscious control.
Neuroscientist
Dr Gert Holstege, from the University of Groningen, who led the
research, said: "The main thing we saw in females is deactivation of
the brain, which was unbelievable; really very pronounced.
"I
think that's the major outcome of the study. What you see is
deactivation of large parts of the brain, especially the emotional
brain, the fear centres."
The only part of a woman's brain that
was activated during orgasm was the cerebellum. Although chiefly
associated with the control of movement, scientists think it may also
play an emotional role.
The cerebellum was also active during fake orgasms, but elsewhere the picture was very different.
"If
you look at the women who faked orgasm, we see the same kind of thing
in the cerebellum taking place, but the cortex, the conscious part of
the brain, is also active," said Dr Holstege.
"Women can imitate orgasm quite well, but in the brain it's not the same."
Even
the body movements made during a real orgasm were unconscious and did
not involve the "thinking" part of the brain, hesaid. This was not the
case with a fake orgasm.
Shutting down the brain during orgasm ensured that obstacles such as fear and stress did not get in the way.
"Deactivation
of these very important parts of the brain might be the most important
necessity for having an orgasm," said Dr Holstege.
"When you are
fearful or have a very high level of anxiety, then it's hard to have
sex because during sex you really have to give yourself and let go."
Men
were studied in the same way. But because the male orgasm during
ejaculation takes such a short time - typically 20 seconds - it was
difficult to obtain meaningful brain scan data.
The scans showed
a similar activation of the cerebellum in men. Dr Holstege suspected
other parts of men's brains mirrored those of women and became
deactivated during orgasm.
However, another part of the study in
which couples stimulated each other for two minutes without reaching
orgasm showed distinct differences between men and women.
In
both, a "fear centre" called the amygdala was deactivated. But in men
alone, the scientists saw activation of an ancient, primitive part of
the brain linked to emotion called the insula.
There was also a
difference in the way touching the genitals affected the somatosensory
cortex of the brain. Women merely experienced a sensory feeling,
whereas in men emotions were involved.
"Men are seeing it as a
big deal, the interpretation of what is happening is important to
them," said Dr Holstege. "Women apparently do not have this idea that,
OK, this is so important. With women the primary feeling is there, but
not the interpretation."
Another odd observation was that the
hippocampus, which deals with memory, was deactivated in women. The
researchers have no idea why.
A total of 13 women and 11 men, ranging in age from 19 to 49, took part in the experiments at Dr Holstege's laboratory.
Presenting
the findings today at the annual meeting of the European Society of
Human Reproduction and Embryology in Copenhagen, Denmark, he admitted
it was a not the easiest of studies to carry out.
The volunteers, all partners, were recruited through advertisements placed in Dutch magazines.
To
put participants in the right mood, members of Dr Holstege's team spoke
reassuringly to them, and dimmed the lighting in the scanning room.
Since
it was vital to remain completely still in the scanner, volunteers had
to have their heads restrained while being sexually stimulated. The
rest of the body was free to move.
"We are neuroscientists, so we're only interested in the brain," said Dr Holstege.
The
men and women, who were all heterosexual and right-handed, stimulated
each others' genitals, but did not have full intercourse.
Participants
lay naked on a table with their head inside the scanner. Dr Holstege
said a major problem was that they got cold feet - literally. A
solution was found in the form of socks supplied by the scientists.
Dr Holstege added that the research could in future lead to better treatments for sexual dysfunction.
The key appeared to be to reduce fear and anxiety - as was illustrated by the aphrodisiac effect on alcohol.
"Alcohol brings down the fear level," said Dr Holstege. "Everyone knows if you give alcohol to a woman it makes things easier."