Pharyngula

Maybe you’ve seen this before: it’s a diagram of the sensory and motor cortex of the brain, with a little man or homunculus drawn over it to illustrate the somatic areas associated with each region. You see where the little man’s knee is on the left image of the sensory cortex? Stick an electrode in there and zap it, and a patient/victim will feel a sensation in his knee. Put the patient in an MRI and tickle his knee, and that region of the brain will light up. Cool, huh?

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Another cute feature: look in the medial longitudinal fissure. You see the homunculus’s toes, and right down there, located beyond the toes, is where the genital sensory area is located. Poke at that with an electrode and…we’re talking happy time at the Mad Scientists’ convention. But notice, though, that in the diagram of the homunculus, the poor creature’s genitals are drawn, and they’re male. It’s a bit sexist, don’t you think?

This bias has now been corrected.

a team led by Lars Michels at University Children’s Hospital in Zurich, Switzerland, used functional magnetic resonance imaging to confirm that the position of the clitoris on the homunculus was in approximately the same position as the penis in men. Barry Komisaruk at Rutgers University in Newark, New Jersey, and his colleagues have now used the same method to map the position of the clitoris, vagina and cervix on the sensory cortex as women stimulated themselves.

I read these things, and I think to myself that I really went into the wrong research field. Oh, well.

They also discovered something else.

Komisaruk also checked what happened when women’s nipples were stimulated, and was surprised to find that in addition to the chest area of the cortex lighting up, the genital area was also activated. “When I tell my male neuroscientist colleagues about this, they say: ‘Wow, that’s an exception to the classical homunculus,'” he says. “But when I tell the women they say: ‘Well, yeah?'” It may help explain why a lot of women claim that nipple stimulation is erotic, he adds.

Now, as a true nerd and as a typical male who has always been mystified by the female sexual response, I feel a deep craving to plumb the mysteries with my own personal fMRI scanner. It’ll also be a research project that will go over well at the next Mad Scientists’ convention.

(Also on FtB)