Life

Our intrepid reporter performs an intimate act in an fMRI scanner to explore the pathways of pleasure and pain

WITH a click and a whirr, I am pulled into the scanner. My head is strapped down and I have been draped with a blanket so that I may touch my nether regions - my clitoris in particular - with a certain degree of modesty. I am here neither for a medical procedure nor an adult movie. Rather, I am about to stimulate myself to orgasm while an fMRI scanner tracks the blood flow in my brain.

My actions are helping Barry Komisaruk at Rutgers University in Newark, New Jersey, and colleagues to tease apart the mechanisms underlying sexual arousal. In doing so, not only have they discovered that there is more than one route to orgasm, but they may also have revealed a novel type of consciousness - an understanding of which could lead to new treatments for pain (see Top-down pain relief).

Despite orgasm being a near-universal human phenomenon, we still don't know all that much about it. "The amount of speculation versus actual data on both the function and value of orgasm is remarkable," says Julia Heiman, director of the Kinsey Institute for Research in Sex, Gender and Reproduction in Bloomington, Indiana.

It is estimated that one in four women in the US has had difficulty achieving orgasm in the past year, while between 5 and 10 per cent of women are anorgasmic - unable to achieve orgasm at all. But without precise data to explain what happens during this experience, there are few treatment options available for women who might want help.

Komisaruk is interested in the time course of orgasm, and particularly when an area of the brain called the prefrontal cortex (PFC) becomes active. The PFC is situated at the front of the brain and is involved in aspects of consciousness, such as self-evaluation and considering something from another person's perspective.

Komisaruk's team recently found heightened activation in the PFC during female climax - something not seen in previous studies of the orgasm. Surprisingly, this was also the case in individuals who can achieve orgasm by thought alone. With fantasy and self-referential imagery often reported as being part of the sexual experience, Komisaruk and colleagues wondered if the PFC might be playing a key role in creating a physiological response from imagination alone. That is why I am here.

Komisaruk instructs me to tap my thumb with my finger for 3 minutes, then to simply imagine my finger tapping my thumb for the next 3 minutes as fMRI tracks where blood is flowing in my brain. Immediately after, I follow the same cycle with Kegel exercises - brief squeezes of the pelvic floor muscles - and then clitoral touches. I'm then asked to self-stimulate to orgasm, raising my free hand to indicate climax. Despite the unique situation, I am able to do so without too much trouble.

Over 30 areas of my brain are activated as I move from start to finish, including those involved in touch, memory, reward and even pain (see "Orgasm snapshot"). As Komisaruk expected, the imagined clitoral touches and Kegel exercises activated the same brain areas as real ones, albeit with somewhat less blood flow. The PFC, however, showed more activation when touches and pelvic squeezes were imagined compared with those that were real. He suggests this heightened activation may reflect imagination or fantasy, or perhaps some cognitive process that helps manage so called "top-down" control - the direct regulation by the brain of physiological functions - of our own pleasure. The team presented their results at the Society for Neuroscience annual conference in San Diego in November 2010.

However, when Janniko Georgiadis at the University of Groningen in the Netherlands, and colleagues, performed similar experiments they found that the same brain region "switched off" during orgasm. Specifically, they saw significant deactivation in an area of the PFC called the left orbitofrontal cortex (OFC).

Altered state

Georgiadis argues that the OFC may be the basis of sexual control - and perhaps only by letting go, so to speak, can orgasm be achieved. He suggests this deactivation may be the most telling example of an "altered state of consciousness" and one not seen, as yet, during any other type of activity.

"I don't think orgasm turns off consciousness but it changes it," he says. "When you ask people how they perceive their orgasm, they describe a feeling of a loss of control." Georgiadis suggests that perhaps orgasm offsets systems that usually dominate attention and behaviour. "I'm not sure if this altered state is necessary to achieve more pleasure or is just some side effect," he says. It is possible that the inability to let go and reach this altered state may be what prohibits individuals with anorgasmia from reaching climax.

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