How does the brain generate orgasm? It’s one of the most under-investigated human experiences but two articles, one in the LA Times and another in The Psychologist, discuss some of the key developments of recent years.
The LA Times article is a good description of some of the most interesting neuroscience studies in this developing field, but is a little uncritical in places.
Apparently “About 43% of women and 31% of men in the U.S. between ages 18 and 60 meet criteria for sexual dysfunctions, according to a 1999 report on the sexual behavior of more than 3,000 U.S. adults”.
This report was a research study published in the Journal of the American Medical Association that classified sexual dysfunction as reporting any one of the following during the last 12 months:
(1) lacking desire for sex; (2) arousal difficulties (ie, erection problems in men, lubrication difficulties in women); (3) inability achieving climax or ejaculation; (4) anxiety about sexual performance; (5) climaxing or ejaculating too rapidly; (6) physical pain during intercourse; and (7) not finding sex pleasurable
Almost all of which fall within the normal range of a year’s worth of regular sexual experiences, which probably explains why a third to almost half of people surveyed experienced at least one – but hardly a marker of a serious medical problem in itself.
It looks at the research on the roles of neurotransmitters in orgasm, as well as what the brain scanning literature tells us about brain activity during sexual arousal and release.
Most interestingly, it has a good discussion of non-genital orgasm:
As reviewed in Komisaruk et al. (2006), there are published reports of orgasms elicited by stimulation also of lips, hand, knee and anus occurring during dreaming sleep, of phantom limbs, from electrical or chemical stimulation of the septum, amygdala or thalamus of the brain and of the spinal cord.
Orgasms have also been described by men and women when they suffer epileptic seizures that are triggered by specific activity (e.g. brushing the teeth: Chuang et al., 2004), or that occur spontaneously. While these epileptic orgasms are in some cases described as ‚Äòunwelcome‚Äô (Reading & Will, 1997), others describe them as pleasurable, one woman refusing anti-epileptic medication for that reason (Janszky et al., 2004)
We have measured autonomic and brain activity during orgasms that women have produced by thought alone. During the thought orgasms, the magnitude of the increases in heart rate, blood pressure, pain threshold, pupil diameter, and brain regions are similar to those that we observe during vaginal or cervical self-stimulation-induced orgasms (Whipple et al., 1992). It is not surprising that in those cases of thought-induced orgasms, the specific genital sensory thalamic and cortical, and specific limb-motoric regions, are not activated.
The article notes that a number of different nerve pathways may serve to communicate sensual stimulation to the brain, which may account for why different sites of stimulation can produce orgasm.
Full discloser: I’m an unpaid associate editor of The Psychologist.