Sorry so long but can't link the article.

“Achieving orgasm, brain-imaging studies show, involves more than heightened arousal. It requires a release of inhibitions and control in which the brain’s center of vigilance shuts down in males; in females, various areas of the brain involved in controlling thoughts and emotions become silent. The brain’s pleasure centers tend to light up brightly in the brain scans of both sexes; especially in those of males (yes we do get rather enthusiastic about the whole thing) . The reward system creates an incentive to seek more sexual encounter, with clear benefits for the survival of the species.

In 1966 gynecologist William Masters and psychologist Virginia Johnson described for the first time the sexual response cycle. Based observations of 382 women and 312 men undergoing some 10,000 such cycles (cycles lol!) The cycle begins with excitation, as blood rushes to the penis in men, and as the clitoris, vulva and vagina enlarge and grow moist in women. Gradually, people reach a plateau, in which they are fully aroused but not yet at orgasm. After reaching orgasm, they enter the resolution phase (cigarette anyone?)

In the 1970’s psychiatrist Helen Singer Kaplan of the Human Sexuality Program at Weill Medical College of Cornell University added a critical element to this cycle, desire, based on her experience as a sex therapist. In her three-stage model, desire precedes sexual excitation, which is then followed by orgasm. Because desire is mainly psychological, Kaplan emphasized the importance of the mind in the sexual experience and the destructive forces of anxiety, defensiveness and failure of communication.

In the late 1980’s gynecologist Rosemary Basson of the University of British Columbia proposed a more circular sexual cycle, which, despite their term, had been described as a largely linear progression in previous work. Basson suggested that desire might both lead to genital stimulation and be invigorated by it. Countering the idea that orgasm is the pinnacle of the experience, she placed it as a mere spot on the circle, asserting that a person could feel sexually satisfied at any of the stages leading up to an orgasm, which thus does not have to be the ultimate goal of sexual activity.

Conventional wisdom casts the male triggers in simplistic sensory terms, with tactile and visual stimuli being particularly enticing. Men are drawn to visual erotica, explaining, the lure of magazines such as Playboy. Meanwhile female desire is supposedly fueled by a richer cognitive and emotional texture. “Women experience desire as a result of the context in which they are inserted-whether they feel comfortable with themselves and the partner, feel safe and perceive a true bond with the partner,” (that is precisely how I feel) Yet sexual imagery devoid of emotional connections can arouse women just as it can men, a 2007 study shows. Psychologist Meredith Chivers, gauged the degree of sexual arousal in about 100 women and men, both homosexual and heterosexual, while they watched erotic film clips. The clips depicted same-sex intercourse, solitary masturbation or nude exercise, performed by men and women and apes.

The researchers found that although nude exercise genitally aroused all the onlookers the least and intercourse excited them the most, the type of actor was more important for the men than for the women. Heterosexual women’s level of arousal increased along with the intensity of the sexual activity largely irrespective of who or what was engaged in it. In fact, these women were genitally excited by male and female actors equally and also responded physically to ape copulation. (LMAO! You go ladies) Gay women however were more particular; they did not react sexually to men masturbating or exercising naked. The men, by contrast, were physically titillated mainly by their preferred category of sexual partner-that is, females for straight men and males for gay men-and were not excited by ape copulation. When it comes to orgasm, simple sensations as well as higher-level mental processes probably also play a role in both sexes.

The relative weights of sensory and emotional influences on orgasm may differ between the sexes, perhaps because of its diverging evolutionary origins. Orgasm in men is directly tied to reproduction through ejaculation, whereas female orgasm has a less obvious evolutionary role. Orgasm in a woman might physically aid in the retention of sperm, or it may play a subtler social function, such as facilitating bonding with her mate (LOL! Go Baby Go!). If female orgasm evolved primarily for social reasons, it might elicit more complex thoughts and feelings in women than it does in men.

But does it? Neuroscientist Gert Holstege of the University of Groningen attempted to solve the male side of the equation by asking the female partners of 11 men to stimulate their partner’s penis until he ejaculated while they scanned his brain using positron-emission tomography. During ejaculation, the researchers saw extraordinary activation of the ventral tegmental area, a major hub of the brain’s reward circuitry; the intensity of this response is comparable to that induced by heroin (Damn, now that’s what I call a hand job honey). Because ejaculation introduces sperm into the female reproductive tract, it would be critical for reproduction of the species to favor ejaculation as a most rewarding behavior. When reversed clitoral stimulation by itself led to activation in areas of the brain involved in receiving and perceiving sensory signals from that part of the body and in describing a body sensation for instance labeling it “sexual.” But when a women reached orgasm , something unexpected happened: much of her brain went silent. Researchers suggest might correspond to a release of tension and inhibition. The scientists also saw a dip in excitation in the dorsomedial prefrontal cortex, which has an apparent role in moral reasoning and social judgment, a change that may be tied to a suspension of judgment and reflection. They also saw a dip in vigilance similar to that seen in men, who generally shoed far less deactivation in their brain during orgasm than their female counterparts. “Fear and anxiety need to be avoided at all costs if a woman whishes to have an orgasm; we knew that, but now we can see it happening in the depths of the brain.” Holstege says. (In other words let go and enjoy the ride ladies).

Continued scientific dissection of the experience of orgasm may lead to new pharmaceutical and psychological avenues for enhancing the experience and medications/psychotherapies for sexual problems.”

The Orgasmic Mind by Martin Portner/Scientific American Mind Magazine