Despite a glut of literature available on how to have more and better orgasms, science is only beginning to unravel the mysteries of the nervous system. The experiences of some paralyzed women prove how little we know: Though seemingly cut off from all feeling below the waist, some have found they still had orgasms when they tried sex.
More mysterious still, some could have orgasms when touched in a spot on the trunk or neck just above the region of injury.
One Philadelphia-area woman who was paralyzed from the waist down in a car accident was overwhelmed to learn she'd never walk again. She was 30, and single. She assumed she'd never enjoy sex again either, though at the time it was a lesser concern.
Ten years later she fell in love. The couple tried sex. "I was fulfilled, I had orgasms," she said. "It was like I was reborn."
Neurologist Barry Komisaruk of Rutgers University has been studying sex in paralyzed women for the last 10 years. Sometimes, the loss of sex was the most devastating and irreconcilable consequence of spinal-cord injury, he says, tearing apart relationships and families.
"Doctors had told many of them their sex life was over because there's no pathway to the brain," Komisaruk said.
A behavioral neuroscientist, he started out studying the nervous systems of rats. In female rats, the vaginal stimulation from sex caused a cascade of hormonal changes and kicked in a painkilling effect more powerful than morphine. There could be a blockbuster drug in this, he reasoned, if he could decode the neurobiology of female rat sex.
He tried severing the three known nerve pathways that connect the genitals to the brain - the pelvic, pudendal and hypogastric nerves. Oddly, the rats reacted to sexual stimulation as if their nerves were intact.
He discovered a new channel for sexual pleasure - the vagus nerve - which threads from the brain through the lungs, intestines, and other internal organs, bypassing the spinal cord.
Could the vagus nerve also channel sexual sensations in humans? To find out, he decided to study women with complete spinal-cord injury.
He and colleague Beverly Whipple brought women into their lab and interviewed them. In their stories, recorded in a 1997 academic paper, most had shut down sexually at first.
"I have no feeling... therefore I can't experience any type of sexual pleasure... . I became I guess you'd call frigid... ice woman... ," one said.
"I went back to teaching full time... I drove my car... everything was in its place except for my liking myself and my sexuality, and feeling like I was a woman again," reported another.
In months or years, many of them began to experiment with sex, either to please a partner or because they were curious. Some discovered they could orgasm from sex, others found their nervous system had become reorganized, so they discovered new hypersensitive regions above their injury that could lead to orgasm.
In the lab, the researchers investigated the women's sexual potential directly by giving them a device called a stimulator, which looks a little like a tampon. It's designed to create sensation in the vagina and cervix.
"Some of the women who realized they still had sensation started crying," Komisaruk said. Until then, they had given up.
Last year, his team began using MRI to look at what was happening in their brains as women were having orgasms.
He found in those with and without spinal injury, it lit up an area called the nucleus accumbens which is, not surprisingly, also activated by nicotine and cocaine.
He also scanned women who had orgasms from being touched above the injury, and found that in the brain it looked like any other orgasm.
Komisaruk and his colleagues are now trying to change patient care to put more emphasis on the possibility of sex after spinal-cord injury. They're also planning more brain scanning to better understand orgasm and compare the male and female versions.
For a phenomenon that many experience several times a week - or even every day - there's still plenty of terra incognita to be explored.
