This is what your brain looks like during an orgasm

(Craig F. Walker / The Denver Post)

Orgasms are a truly altered, if fleeting, state of consciousness. And most people (though not all) experience them somewhat regularly.

So it's a bit surprising how seldom we talk about orgasms publicly — and scientifically, how little we know about them.

researchers have asked people to lie in mri machines and bring themselves to orgasm

"There's just a lot we still don't understand about orgasms," says Barry Komisaruk, a Rutgers neuroscientist who studies the topic. As Julia Heiman, an Indiana University sex researcher, once put it to New Scientist, "The amount of speculation versus actual data on both the function and value of orgasm is remarkable."

Komisaruk, working with legendary retired sex researcher Beverly Whipple, has spent decades asking men and women to lie down in an fMRI machine and bring themselves to orgasm. Other labs have used PET scanners and other techniques to see what's going on inside the brain of someone having one.

All these studies — intended to establish basic knowledge that could eventually help people who have trouble achieving orgasm — are small, and their findings might not hold for absolutely everyone. But they've uncovered a number of surprising observations about how orgasms work.

1) Orgasms literally take over your brain

Komisaruk's experiments have shown that in both men and women approaching orgasm, a predictable series of events occurs in the brain. Not surprisingly, as sexual stimulation occurs it leads to activation of brain regions known to be involved in processing our sense of touch.

Areas of the sensory cortex that respond to stimulation to the clitoris, cervix, and vagina. (Komisaruk et al 2011)

From there, however, a number of seemingly unrelated brain areas — such as the limbic system (involved in memory and emotions), the hypothalamus (involved in unconscious body control), and the prefrontal cortex (involved in judgment and problem solving) — join in, with one after another showing heightened levels of activation.

By the time you actually experience an orgasm, "more than 30 major brain systems are activated," Komisaruk says. "It's not a local, discrete event. There's no 'orgasm center.' It's everywhere."

2) Female and male orgasms look more similar than you'd expect

While there are some clear physiological differences between female and male orgasms (female orgasms last about 20 seconds, rather than 10, for instance), experiments at the Rutgers lab and elsewhere have shown that in the brain, an orgasm is an orgasm, regardless of someone's sex.

"We see all the same regions activated," Komisaruk says. PET scan research conducted at the University of Groningen in the Netherlands has come to the same conclusion.

Komiasaruk points to an old study from the 1970s that suggested this commonality before the fMRI or PET scan was even invented. In it, researchers asked participants to write down descriptions of what it felt like to have an orgasm. Then they removed all mention of specific body parts and asked a panel of 70 psychologists, sex therapists, and gynecologists to identify whether each description was written by a man or a woman. The judges — whether male or female themselves — were unable to identify them at rates any better than chance.

3) Orgasms seem to act as a painkiller

There's heightened activity in a range of brain areas during orgasm. (Barry Komisaruk)

Earlier experiments conducted by Whipple and Komisaruk suggested that orgasms and sexual stimulation as a whole might cause people's pain tolerance to increase.

The pair determined this with a machine that squeezed a person's finger with steadily increasing force until it hurt. When women were asked to masturbate, their pain tolerance went up by nearly 50 percent. Whipple and Komisaruk also tested various sorts of distractions as controls, and determined it wasn't simply that the masturbation distracted the women, but that it actually affected their perception of the pain.

Subsequent research by Whipple even suggested that vaginal stimulation during childbirth increases pain tolerance — and that the agony of childbirth would be even worse without this mechanism.

All this is somewhat surprising given that the researchers' fMRI scans have found heightened activity in a pair of brain regions (the insula and anterior cingulate cortex) that are known to be involved in pain. But Komisaruk suspects the scans might actually be showing inhibitory activity in these areas — that is, neurons firing as part of networks that block perception of pain, rather than transmit it.

4) Orgasms might also shut down fear and impulse control

The PET scan experiments by the University of Groningen group also found significantly decreased activity in the amygdala, a brain region that's crucial for our perception of fear, and the orbitofrontal cortex, an area involved in impulse control. Lead author Gert Holstege has interpreted this as evidence that at the moment of orgasm, perception of fear and ability to control impulses are both shut down entirely.

But there could be other explanations, especially since PET scans measure brain activity over the course of several minutes. "I think what they're seeing is simply the arousal system shutting off after the orgasm," says Kim Wallen, an Emory psychologist who's conducted work on orgasms.

5) Some people can bring themselves to orgasm just by thinking about it

A number of people have the ability to make themselves orgasm with their thoughts alone — they don't need to physically stimulate themselves or have sex to do it. Whipple and Komisaruk have seen several women achieve this inside the fMRI machine.

"Their brain activity is very similar to women who have orgasms from physical self-stimulation," Komisaruk says. This even includes heightened activity in the sensory cortex, the area that primarily responds to touch. "Just thinking about stimulation, it turns out, is a very potent way of stimulating this region," he says.

6) The idea that women can only orgasm through clitoral stimulation is a myth

There's a big myth that goes back to the Kinsey Reports (a series of reports published in the 1950s by male sex researchers), which holds that women can only experience orgasm as a result of direct stimulation to the clitoris. But though it's the source of most female orgasms, some women have long reported experiencing vaginal orgasms, as well.

Whipple and Komisaruk have uncovered new evidence for this. They recruited participants who had severed spinal cords (the result of accidents), which paralyzed them below the waist and prevented any transmission of sensation from their clitorises. However, these women were still able to bring themselves to orgasm, and fMRIs suggested that their vagus nerves — which connect the brain to the uterus and the cervix but run outside the spinal cord — were responsible for transmitting stimulation from the vagina.

The vagus nerve, which conducts sensation from the vagina and cervix and runs outside the spinal cord, might also contribute to orgasms. (Georgia Highlands College)

This doesn't mean there's a specific organ called the "G-spot" (its existence is still hypothetical), but it confirms that stimulation to areas other than the clitoris can lead to orgasm.

7) Lots of people have trouble orgasming at all

Most of this work is motivated by the fact that a fair percentage of people — disproportionately but not exclusively women — have trouble orgasming at all.

Scientists still don't understand all the causes of this condition, formally called anorgasmia. Many cases might just be a result of someone never getting the necessary stimulation (from either a partner or oneself), which is why some sex coaches have had success with masturbation classes for people with chronic anorgasmia. Lots of people who take certain types of antidepressants (namely, selective serotonin reuptake inhibitors, or SSRIs) also have trouble achieving orgasms as a side effect, and it's been found that for both men and women, Viagra can be an effective treatment.

But there are other people who experience the problem without any apparent cause. Study of twins suggests that genetics may be involved.

Further reading

• Reporter Kayt Sukel's account of having an orgasm inside an fMRI machine
• Donating orgasms to science: A day in the life of a sex researcher
• The economics of faking orgasm

WATCH: 'Life looks really different through an MRI machine'

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