Females reclaim the homunculus

Females reclaim the homunculus
I have been teaching undergraduate physiotherapists for many years in a semester long pain sciences course at the University of South Australia. A key paradigm that we teach is the neuromatrix and this is supported with stories of phantom pain and changes in somatosensory and other homunculi. There is quite a prominent penis on most somatosensory homunculi [1], perched precariously near the toes, and this is usually pointed out as a variant of the somatotopic organisation (the neuronal map of the body in the brain in the central nervous system). Many have pondered on this relationship and foot fetishes.

One semester, I had just finished my lecture on the neuromatrix, phantoms and the homunculi and was about to go when a concerned looking young female student approached me and said “do I really have a penis in my brain?”. No I stuttered, “you probably have a vagina, but no one has really researched it”. “Why not?”, she demanded. “This is important.” I had no answer.

Women have been badly treated in research. Male animals are easier to research and often women miss out on accolades (think of Rosalind Franklin the British X-Ray crystallographer whose contribution to the exposure of the DNA helix in 1953 was hardly recognised by Watson and Crick) But I am digressing…

The virtual vagina
Finally, the location of the human vagina, cervix, clitoris and nipples has now been mapped in the brain [2]. While it might seem obvious in hindsight, the findings are as follows:

1/ The clitoris is in the same place as the penis
2/ Vaginal stimulation activates different areas of the brain to clitoral stimulation
3/ Nipple stimulation not only activates the chest on the homunculus it also activates the genitals.

Not really surprising…

This activates that?
I wish the scientists (including those writing in “New Scientist”) would not talk about “this activating that” as though the brain works in a linear way and A turns on B then turns on C. All this linear thinking (another example is the notion that pain affects movement when, in the brain, activation of movement related neurones is a part of a pain construction) is overlooking the fact that we are just a bit more complex than reductionist scientists and clinicians make out sometimes. The pelvic representation in the brain is likely to already be activated at the thought of being in a study that involved stimulating it – it’s all occurring at the same time.

The virtual vagina – so what?
The first thing is that I have already updated my lecture notes in the pursuit of completeness. But it is tempting to say “so what” or even that such research is waste of money. And as the New Scientist review points out, women have been telling us about nipple stimulation and the difference between vaginal and clitoral stimulation for ever.

But lateral and thinking therapists can take this further. We can assume that with pelvic pain and lack of normal pelvic activity, that the entire pelvis and genitals are probably ‘smudged’ in the brain. The scientists should be able to show this soon, and the images – with appropriate education – should be helpful for many patients. (i.e. “yes, it’s real, measurable and changeable”). We now know that breast stimulation is probably a way of pacing for pelvic pain). Aspects of the graded motor imagery programme, which have shown some success for chronic neuropathic pain [3], should be trialled in pelvic pain states. We could hypothesise that the yoga lotus position (sitting with the feet pressed together in the groin) could help sculpt the clarity of the foot/genital representational boundaries in the brain.

Pelvic pain is a problem for men and women – some estimate the prevalence as similar to back pain [4]. We want to address it at the NOI 2012 Neurodynamics and the Neuromatrix conference. The information from plenary speakers such as Lorimer Moseley (the body matrix), Sandy McFarlane (PTSD) Fiona Wood (thinking yourself whole), Frank Keefe (coping with disease related pain) and the plenary session from Michel Coppieters’ team on peripheral neuropathic pain will filter to two workshops directly on pelvic pain and many related others (eg Mindfullness, Feldenkrais, Latin dance for the pelvis). And I feel as though we are doing something for the student miffed about the sexist homunculus! -David

Do you want to contribute?
We would love to hear your thoughts on this one in terms of scientific benefits (or not) and the future implications of this particular news. For each question answered below we will post a copy of Explain Pain (book, ebook or audio) to the person with our favourite answer.

1/ Is this research worthwhile?
2/ What are some alternate ways this information could be utilised?
3/ Where to from here?

Kell, C.A., et al., The Sensory Cortical Representation of the Human Penis: Revisiting Somatotopy in the Male Monunculus. The Journal of Neuroscience, 2005. 25(25): p. 5984-5987.
Komisaruk, B.R., et al., Women’s Clitoris, Vagina, and Cervix Mapped on the Sensory Cortex: fMRI Evidence. Journal of Sexual Medicine, 2011. July 28.
Moseley, G.L., Graded motor imagery for pathologic pain. Neurology, 2006. 67: p. 1-6.
Howard, F.M., Diagnosis and treatment of persistent pelvic pain, in Pain 2010. An updated review, J. Mogil, Editor. 2010, IASP Press: Seattle.


The Neurodynamics and the Neuromatrix Conference 2012
Women’s Clitoris, Vagina, and Cervix Mapped on the Sensory Cortex: fMRI Evidence
Sex on the brain: What turns women on, mapped out
Graded motor imagery
Explain Pain *ebook*


11 Responses to “Females reclaim the homunculus”

  1. ianpstevens Says:

    I am fascinated by the brain research but and happy that the female sensuatlity has been discovered ! I like your incorporation of thoughts relating to body mapping etc (Sandra Blakeslees book should be standard physio reading …The body has a mind of its own)
    Dont you think though that a lot of these findings can be highly influenced by cultural attitudes and situations ?? Example…………
    ‘Nipple stimulation not only activates the chest on the homunculus it also activates the genitals’?
    Why would this happen if the prime function is to provide food for infants ……what would be the point of becoming aroused if this were the case ?
    I think that without cultural and contextural understanding a lot of the brain scanning research has its limitations…

  2. Kønsorganer på hjernen « videnomsmerter Says:

    […] Hvorvidt denne viden får betydning for samliv, terapi eller forskning fremadrettet er tvivlsomt, men ikke desto mindre har min kollega, David Butler, formået at bruge emnet til hans nyeste blogindlæg… Læs evt. David´s betragtninger omkring clitoris´ sensoriske cortex ved at klikke her […]

  3. Sandy Says:

    I think this is amazingly, awesomely cool. Chronic pelvic pain is tricky from a clinician point of view because there are tons of highly charged social and emotional issues stacked uncomfortably on top of local pain and (I assume) central sensitization.
    I have been trying interesting things in the clinic with chronic pelvic pain (male and female). I steal from the CRPS research and the lack of evidence for applying those techniques to the pelvic floor is getting irritating. There is what appears to be success with evaluating where the person is on a local tissue versus central sensitization basis. We get creative with how thoughts and photos can trigger pain responses, and even more creative with how to desensitize those responses so that they can reclaim all those lovely normal pelvic functions that are so healthy for us.
    I don’t KNOW that I am using the best approach. I am making gigantic assumptions about starting with laterality drills, challenging them with the foot cards, need better sensory cues especially for guys (anyone want to email me on male sensory cue ideas?) and doing graded exposure…. At the very least we laugh often and enthusiastically about all of this.
    So what is the best way to restore normal sensitivity and function to the pelvic floor? Does the observation that pelvic pain people always chose the hand vs the foot cards have to do with subtle cues from me, chance, or that they are avoiding the foot ones for a sensory? Should we have pelvic cards for guys? What about women? I want this research to happen and I have loads of questions.

  4. Karin Hilfiker Says:

    YES, of course this new brain mapping research is incredibly important! While, as noted, none of the findings come as a big suprise to women and those who love them, having the science validate what we’ve already discovered through experience and experimentation is exciting and, of course, in this evidence based world, lays the foundation for further research and clinical application. One connection that immediately comes to mind is a technique advocated by natural childbirth advocates: stimulation of the nipples to encourage opening of the cervix during childbirth — this makes complete sense given their proximity in the homonculus.
    In fact much of the work of Ina May Gaskin, America’s ‘mother of midwifery”, is right up the NOI alley — she writes extensively of how womens’ fear of labor and delivery, and particularly their fear of pain during labor, slows down the labor itself through neurophysiological feedback mechanisms. She devotes a whole chapter in one of her books to the “Law of the Sphincters” in which she describes how our sphincters, excretory as well as cervical and vaginal sphincters, are wired to close when the owner person feels upset, frightened, humiliated or self-conscious, and can only relax and open in the absence of these emotions.
    Thanks for the post, very stimulating! 🙂

  5. Kim Wilson Says:

    Hi guys!

    I like to see that the research has been done! But here is something to think about…….

    A pregnant woman the day before she gives birth ( although she may not feel like it!) would still have the normal activation of chest and clitoris areas with nipple stimulation. The next day though, with newborn baby, is getting assumedly more nipple stimulation but is certainly not feeling the same connection with the clitoris! (I don’t think I am alone in thinking this????)

    So, tell me, are hormones playing such a strong role here that we are able to shut out this double area of activation, or has the homonculus managed to change overnight???

    From one day to the next the sensation felt in stimulating the same area changes completely.

    Does nipple stimulation in lactating women still activate the clitoral regions in the homonculus?

    Does this perhaps hormonal/mental influence allow us to make assumptions as to why women are typically more emotional lovers and men more physical???

  6. inbar Says:

    …..following the last post,not only nipple stimulation changes completely in lactating women ,in some women a year or two after breast feeding is over
    nipple stimulation still doesn’t recover its previous joyful role and its relationship with the genitals,leading to lack of normal pelvic activity and a cycle of deprived stimulation.
    rehabilitation program is needed, dedicated to over stimulation of the nipples and the return of the happy genitals.

  7. Jenlangford Says:

    So I burnt my bras for nothing! Yes this is an important piece of research.
    A few thoughts…….firstly nipple stimulation does seem the obvious graded path to take, however in these persisting pelvic pain states touch can be tricky
    ( sexual or other). The whole psychosexual thing complicates rehab and there can be an aversion to touch anywhere. Perhaps something creative in prone for starters? Feet? Chest movement? ……then onto nipples?
    What we want next is to see how the smudged homunculus looks, that might give some mighty clues for where and how we pace these pain states. It would also be interesting to know what the brain does with imagery of pelvic activity (interesting pics, no doubt!)
    Great blog David and great to have this baseline information now.

  8. Observing virtual arms that you imagine are yours Says:

    […] own body and we think that visual feedback is good. I refer the interested reader to the latest noinotes on the virtual vagina – time to get out the mirror?  Well, if we do, this study suggests that we would be well served […]

  9. Rafeef AlJuraifani Says:

    after attending the NOI 2012 this idea of female pelvis representation in the brain has been always on my mind. It was nice to find the scientific research paper .
    regarding nipple stimulation, I just wonder what would happen in women post mastectomy? like any amputated body part, wouldn’t it still be there “virtually”? what would stimulate the “virtual nipple”?…I guess I just have more questions now!!!

  10. Observing virtual arms that you imagine are yours Says:

    […] own body and we think that visual feedback is good. I refer the interested reader to the latest noinotes on the virtual vagina – time to get out the mirror?  Well, if we do, this study suggests that we would be well served […]

  11. Meghan Says:

    I have been searching the internet for a female homunculus because i’ve been obsessed with the homunculus figure since i first saw it freshman year in intro psych. I am now taking a ceramics class and trying to figure out how to interpret this iconic image in the feminine because i thought it would be interesting. Came across this article and it really helped me decide where to take this project imaginatively. Email me if you are interested in seeing the finished product 🙂

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