/ 29 June 2005

Hot passions and cold feet

Women may fool their sexual partners by faking orgasm, but their brains cannot lie. Reaching a proper sexual climax is, for women at least, a mind-blowing event. Large parts of their brains that deal with emotion and fear appear to shut down so that they can enjoy the thrill.

Women may fool their sexual partners by faking orgasm, but their brains cannot lie. Reaching a proper sexual climax is, for women at least, a mind-blowing event. Large parts of their brains that deal with emotion and fear appear to shut down so that they can enjoy the thrill.

A series of experiments at the Univerity of Groningen in The Netherlands used brain scans to map what happened in men’s and women’s heads while their partners sat by their prone bodies, sexually stimulating them.

The tests involved 13 women and 11 men aged 19 to 39. Women told the researchers when they faked orgasm, but the truth was there on the scans anyway.

Professor Gert Holstege reported the findings at a conference in Copenhagen, Denmark, organised by the European Society of Human Reproduction and Embryology.

”The main thing we saw was deactivation in women,” he said. ”It was unbelievable, very pronounced. I think that is the major outcome of the study. You see extreme deactivation of large portions of the brain, especially the fear centres, the brain that controls emotions.”

The main part of the brain that seemed active was the cerebellum, linked to control of movement, but scientists also think it may have an emotional role. This was active in fake orgasms, too, but otherwise there was a different picture.

”If you look at women who faked orgasm you see the same kind of thing in the cerebellum, but the cortex, the conscious part of the brain, is also active,” Holstege said.

To reach true climax, women needed to ensure that fear and stress did not get in the way. ”The deactivation of these very important parts of the brain might be the most important thing necessary to have an orgasm. If you are in a high level of anxiety it is very hard to have sex.”

Men were studied in the same way, but because it typically took only 20 seconds to reach ejaculation, it was difficult for neuroscientists to obtain and interpret data. But Holstege suspects that the change in brain pattern may mirror that of women.

Another part of the study in which the volunteers were stimulated without reaching orgasm showed differences in brain response, however. In both sexes, an area called the amygdala, a fear centre, was deactivated, but in men, an ancient part of the brain linked to emotion, called the insula, became more active.

Other differing brain patterns between the sexes suggested that men respond differently to having their genitals stimulated. Men appeared to want to rationalise the experience by interpreting its importance, while women merely enjoyed the sensation.

”Men are seeing it as a big deal, the interpretation of what is happening is important to them,” Holstege said. ”Women apparently do not have this idea that this is so important. With women the primary feeling is there, but not the interpretation.”

The volunteers, all heterosexual and right-handed, were recruited through Dutch magazines. Since it was vital for them to remain completely still in the scanner, they had to have their heads restrained, although they were free to move the rest of their bodies.

”We are neuroscientists, so we’re only interested in the brain,” said Holstege. There were, however, some physical matters that had to be attended to as well. ”A major problem was they got cold feet, so they put socks on,” he added.

Holstege hopes his work may lead to treatments that lower anxiety levels and which reduce sexual dysfunction.” Alcohol brings down fear levels. Everyone knows if you give alcohol to women it is easier,” he said. — Â