Brain control of the clitoris and vagina, as well as of the nipple, was not known in detail until a decade ago. Komisaruk and colleagues at the Psychology Department of Rutgers University, in Newark, New Jersey, USA, established what they called the genital sensory cortex in women.
Komisaruk BR, Wise N, Frangos E, Liu W‐C, Allen K, and Brody S. Women’s clitoris, vagina and cervix mapped on the sensory cortex: fMRI evidence. J Sex Med 2011; 8:2822–2830.
In their experiment, the women applied clitoral, vaginal, and cervical self‐stimulation while the regional brain responses were identified with functional MRI. Previously, the same regions had been identified in the Penfield homunculus based on electrical stimulation of the brain in men, and male anatomy was already relatively well studied.
Penfield W. Rasmussen T. The cerebral cortex of man. Macmillan, 1950
Foerster O. Sensible corticale Felder. in: Bumke O. Handbuch der Neurologie. Springer, 1936: 358-448
Penfield W. Boldrey E. Somatic motor and sensory representation in the cerebral cortex of man as studied by electrical stimulation. Brain. 1937; 60: 389-443
Knowledge of the male neurological anatomy and function was already relatively well known.
Kell C.A et al The sensory cortical representation of the human penis: Revisiting somatotopy in the male homunculus. J Neurosci. 2005; 25: 5984-5987
Georgiadis J. and Holstege G. Human brain activation during sexual stimulation of the penis. J Comp Neurol. 2005; 493: 33-38
Bradley W.E. et al Human cerebrocortical potentials evoked by stimulation of the dorsal nerve of the penis. Somatosens Mot Res. 1998; 15: 118-127
Makela J.P. et al. Dorsal penile nerve stimulation elicits left‐hemisphere dominant activation in the second somatosensory cortex. Hum Brain Mapp. 2003; 18: 90-99
Nakagawa et al. Somatosensory evoked magnetic fields elicited by dorsal penile, posterior tibial, and median nerve stimulation. Electroencephalogr Clin Neurophysiol. 1998; 108: 57-61
Narici L. et al Neuromagnetic somatosensory homunculus: A non‐invasive approach in humans. Neurosci Lett. 1991; 2: 51-54
The Rutgers group set out towards understanding the neural systems underlying female sexual response. They confirmed the anatomical and functional female data, and reviewed the relevant literature in a series of papers.
Komisaruk B.R. et al Brain activation during vaginocervical self‐stimulation and orgasm in women with complete spinal cord injury: fMRI evidence of mediation by the Vagus nerves. Brain Res. 2004; 1024: 77-88
Komisaruk B.R. et al The science of orgasm. The Johns Hopkins University Press, 2006
Komisaruk B.R. et al Women’s clitoris, vagina and cervix mapped on the sensory cortex, using fMRI. Soc Neurosci. 2009; 562: 18
In the original investigation they mapped the sensory cortical fields of the clitoris, vagina, uterine cervix and nipple, Sensory cortical responses to clitoral, vaginal, cervical, and nipple self‐stimulation were mapped using functional magnetic resonance imaging (fMRI). For points of reference on the sensory homunculus, they mapped responses to stimulation of the thumb and great toe. Clitoral, vaginal, and cervical self‐stimulation activated regions clustered in the medial cortex of the parietal lobe, the so-called medial paracentral lobule. Nipple self‐stimulation activated the genital sensory cortex and the thoracic region of the sensory homunculus.
Similar results were described in:
Michels L. et al The somatosensory representation of the human clitoris: An fMRI study. Neuroimage. 2010; 49: 177-184
Allison et al. Localization of functional regions of human mesial cortex by somatosensory evoked potential recording and by cortical stimulation. Electroencephalogr Clin Neurophysiol. 1996; 100: 126-140
Georgiadis J. et al Regional cerebral blood flow changes associated with clitorally induced orgasm in healthy women. Eur J Neurosci. 2006; 24: 3305-3316
Vaginal, clitoral, and cervical regions of activation were differentiable, consistent with innervation by different afferent nerves and different behavioral correlates. Activation of the genital sensory cortex by nipple self‐stimulation suggests a neurological basis for women’s reports of its erotogenic quality.
Further reading
Kinsey A. Sexual behavior in the human female. WB Saunders, 1953
Masters W. and Johnson V. Human sexual inadequacy. Little, Brown, 1970
Paget L. The big O. Broadway Books, 2001
Netter F.H. The ciba collection of medical illustrations. Nervous system. Part I. Anatomy and physiology. Ciba Pharmaceutical, 1986
Blatow M et al. FMRI reflects functional connectivity of human somatosensory cortex. Neuroimage. 2007; 37: 927-936
Sutherland M.T. The hand and the ipsilateral primary somatosensory cortex. J Neurosci. 2006; 26: 8217-8218
Haridas C. and Zehr E.P. Coordinated interlimb compensatory responses to electrical stimulation of cutaneous nerves in the hand and foot during walking. J Neurophysiol. 2003; 90: 2850-2861
Richter C. Mysterious form of referred sensation in man. Proc Natl Acad Sci U S A. 1977; 74: 4702-4705
O’Connell H.E. et al . The anatomy of the distal vagina; towards unity. J Sex Med. 2008; 5: 1883-1891
Brody S. and Kruger T.H.C. The post‐orgasmic prolactin increase following intercourse is greater than following masturbation and suggests greater satiety. Biol Psychol. 2006; 71: 312-315
Whipple B. and Komisaruk B.R. Analgesia produced in women by genital self‐stimulation. J Sex Res. 1988; 24: 130-140
Brody S. Blood pressure reactivity to stress is better for people who recently had penile‐vaginal intercourse than for people who had other or no sexual activity. Biol Psychol. 2006; 71: 214-222
Cutler W.B. Sexual response in women. Obstet Gynecol. 2000; 95: S19
Tao P. and Brody S. Sexual behavior predictors of satisfaction in a Chinese sample. J Sex Med. 2011; 8: 455-460
Costa R.M. and Brody S. Women’s relationship quality is associated with specifically penile‐vaginal intercourse orgasm and frequency. J Sex Marital Ther. 2007; 33: 319-327
Brody S. The relative health benefits of different sexual activities. J Sex Med. 2010; 7: 1336-1361
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Dr Paulo Bittencourt