Look Ma, No Hands!
Specifically, Drs. Komisaruk and Whipple of Rutgers have used MRI scans to look at the brains of women during both mental and physical orgasms. Previous studies had shown that the general physical responses to orgasm - increased heart rate and blood pressure, pupil dilation, and increased pain tolerance - were identical to manually obtained orgasms for women who thought themselves off. The MRI results showed the same similarity - the same parts of the brain were active in women during orgasms regardless of whether the orgasm was induced physically or mentally. Specifically the nucleus accumbens (involved in reward circuitry), paraventricular nucleus of the hypothalamus (involved in the release of mood enhancing hormones oxycontin and vasopressin), hippocampus (this one, oddly, is involved in long-term memory storage and spatial navigation - the fantasy component perhaps?), and anterior cingulate cortex (involved in motivation and emotional responses) showed increased blood flow during orgasms for women in both groups. The only exception was the amygdala - which did not light up during thought orgasms. The researchers speculate that this is because the amygdala is involved in sensing physical sensations in the genitals. All of this indicates that 1) the brain's response to orgasms is highly complex, and 2) mental orgasms cause the same responses as physical ones and therefore are "real" orgasms (in case you were doubting).
Interestingly, the thoughts used to induce orgasms varied greatly between women. The researchers describe them as ranging from erotic to pastoral to abstract. Interviewees in the Daily Mail get a little more specific - some women fantasized about sexual situations, while others imagined sensual, but not sexual, activities like walking on a beach. At least one women seems to have her body so well trained she can basically just command it to have an orgasm and...voila! It seems that for some women this ability comes naturally while for others it can be learned. Many women find they can orgasm involuntarily from the mental stimulation of dreams. Having waking mental orgasms is simply a matter of being able to deliberately replicate this phenomenon, and probably a good number of women could do it if they took the time to figure out how. The keys to learning seems to involve complete relaxation and figuring out exactly what gets you hot in the right ways. Based on the descriptions of women who can induce mental orgasms, this won't necessarily involve strictly sexual scenarios, but may include breathing exercises, romantic feelings, or non-sexual pleasurable sensations (I'm pretty sure thinking about chocolate for long enough would work for me). While it may seem like a lot of work to train your body to do this when more conventional means are equally effective, having the ability to call on orgasms mentally could be very useful to the many women who have difficulty coming during sex - sort of like high-powered fantasizing.
Of course, this is once again being framed as further evidence that while men are physical creatures sexually, women are primarily mental creatures. Which I personally think is a load of horseshit. No actual research has been done (that I can find anyway) to determine if men have this same ability, but if dream-orgasms are an indicator that waking mental orgasms are possible then the very commonness of wet dreams among men ought to imply that under the right conditions a man should be able to get off without physical stimulation while conscious as well. In fact, I imagine it's pretty common, but instead of treating it as a cool type of male orgasm we just dismiss it as premature ejaculation. When men get so worked up they get off with little or no physical contact, it's an accident. When women do it it's mystical and wonderful. (To be fair, in the context of sex it is more frustrating when men do it, since men, unlike women, usually can't keep going post-orgasm.) As with women, it's probably something that some men can do easily while others can only achieve mental orgasms with deep concentration and lots of practice, and the fact that many men train themselves to withhold orgasms to prolong sex probably makes it more difficult for some men than it might be otherwise. Still, it's worth adding to the repertoire of masturbation techniques if you find you are able to control your orgasms mentally. I'm sure just as many pajiboys as pajibettes would love to be able to get their rocks off while leaving both hands free to type (just...once again, keep it to yourself if you do, thanks). Unfortunately, don't expect any research on male mental orgasms in the near future. Not only does there not seem to be a lot of interest, but because men's orgasms are typically shorter in duration than women's, they're harder to study with techniques like MRI imaging.
The research on thinking yourself off indicates that sexual pleasure does have a large mental component on top of the physical one -- for women at least, and I suspect for men as well, even if no one will acknowledge it. Mood is important; being able to fantasize both on your own and when with another person is important. Once again, knowing yourself and what you like is the best way to insure that you enjoy your sexuality to the fullest, so if you need to think about walking along a moonlit beach to get off during sex, don't worry about it. Just do what you need to do and enjoy the results.
Dr. Pisaster has a doctorate in biophysics, not actually anything sexy. She does however enjoy having sex, reading about sex, and talking about sex. Especially when she's had a little whiskey.