Brain Activation during Sexual Arousal and Orgasm in Women

Using fMRI, we ascertained that the region of the medulla oblongata to which the vagus nerves project (the Nucleus of the Solitary Tract -- NTS) is activated by VCSS. We also used an objective measure, VCSS-induced analgesia response to experimentally-induced finger pain, to ascertain the functionality of this pathway.

During VCSS, several women experienced orgasms. Brain regions activated during orgasm included the hypothalamic paraventricular nucleus, amygdala, accumbens-bed nucleus of the stria terminalis-preoptic area, hippocampus, basal ganglia (especially putamen), cerebellum, and anterior cingulate, insular, parietal and frontal cortices, and lower brainstem (central gray, mesencephalic reticular formation, and NTS).

We conclude that the vagus nerves provide a spinal cord-bypass pathway for vaginal-cervical sensibility and that activation of this pathway can produce analgesia and orgasm. The brain regions activated during orgasm elicited by VCSS in able-bodied women were comparable to those in women with complete spinal cord injury.