Science of orgasm

This month’s Scientific American Mind unpacks the neurology of orgasm.
It summarizes some very intriguing and also controversial research. For
example, brain scans seem to show that orgasms aren’t just about
heightened arousal but also the silencing of the brain’s “center of
vigilance” to lose all inhibitions. From Scientific American Mind:

To find out whether orgasm looks similar in the female
brain (as it does in the male brain), (University of Groningen
neuroscientist Gert) Holstege’s team asked the male partners of 12
women to stimulate their partner’s clitoris–the site whose excitation
most easily leads to orgasm–until she climaxed, again inside a PET
scanner. Not surprisingly, the team reported in 2006, 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 woman reached orgasm, something unexpected
happened: much of her brain went silent. Some of the most muted neurons
sat in the left lateral orbitofrontal cortex, which may govern
self-control over basic desires such as sex. Decreased activity there,
the 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.

Brain activity fell in the amygdala, too, suggesting a
depression of vigilance similar to that seen in men, who generally
showed far less deactivation in their brain during orgasm than their
female counterparts did. “Fear and anxiety need to be avoided at all
costs if a woman wishes to have an orgasm; we knew that, but now we can
see it happening in the depths of the brain,” Holstege says. He went so
far as to declare at the 2005 meeting of the European Society for Human
Reproduction and Development: “At the moment of orgasm, women do not
have any emotional feelings.”