Article

Functional MRI of the brain during orgasm in women.

Department of Psychology, Rutgers,The State University of New Jersey, Newark 07102, USA.
Annual review of sex research 02/2005; 16:62-86.
Source: PubMed

ABSTRACT Women diagnosed with complete spinal cord injury (SCI) at T10 or higher report sensations generated by vaginal-cervical mechanical self-stimulation (CSS). In this paper we review brain responses to sexual arousal and orgasm in such women, and further hypothesize that the afferent pathway for this unexpected perception is provided by the Vagus nerves, which bypass the spinal cord. Using functional magnetic resonance imaging (fMRI), we ascertained that the region of the medulla oblongata to which the Vagus nerves project (the Nucleus of the Solitary Tract or NTS) is activated by CSS. We also used an objective measure, CSS-induced analgesia response to experimentally induced finger pain, to ascertain the functionality of this pathway. During CSS, 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.

2 Bookmarks
 · 
404 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: IntroductionThe vaginal canal is an active and responsive canal. It has pressure variations along its length and shows reflex activity. At present, the prevailing idea is that the vaginal canal does not have a sphincter mechanism. It is hypothesized that an active vaginal muscular mechanism exists and might be involved in the pathophysiology of genito-pelvic pain/penetration disorder.AimThe aim of this study was to detect the presence of a canalicular vaginal “sphincter mechanism” by measuring intravaginal pressure at different levels of the vaginal canal during voluntary pelvic floor contractions and during induced reflexive contractions.Methods Sixteen nulliparous women, without sexual dysfunction and pelvic floor trauma, were included in the study. High-resolution solid-state circumferential catheters were used to measure intravaginal pressures and vaginal contractions at different levels in the vaginal canal. Voluntary intravaginal pressure measurements were performed in the left lateral recumbent position only, while reflexive intravaginal pressure measurements during slow inflation of a vaginal balloon were performed in the left lateral recumbent position and in the sitting position.Main Outcome MeasuresIntravaginal pressures and vaginal contractions were the main outcome measures. In addition, a general demographic and medical history questionnaire was administered to gain insight into the characteristics of the study population.ResultsFifteen out of the sixteen women had deep and superficial vaginal high-pressure zones. In one woman, no superficial high-pressure zone was found. The basal and maximum pressures, as well as the duration of the autonomic reflexive contractions significantly exceeded the pressures and the duration of the voluntary contractions. There were no significant differences between the reflexive measurements obtained in the left lateral recumbent and the sitting position.Conclusion The two high-pressure zones found in this study, as a result of voluntary contractions and, even more pronounced, as a result of reflexive contractions on intravaginal stimulation, support the hypothesis that the vaginal canal has an active and passive canalicular sphincter mechanism. Further investigation of this sphincter mechanism is required to identify its role in the sexual response and genito-pelvic pain/penetration disorder. Broens PMA, Spoelstra SK, and Weijmar Schultz WCM. Dynamic clinical measurements of voluntary vaginal contractions and autonomic vaginal reflexes. J Sex Med **;**:**–**.
    Journal of Sexual Medicine 11/2014; · 3.51 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: IntroductionDespite recent advances in understanding orgasm variation, little is known about ways in which sexual orientation is associated with men's and women's orgasm occurrence.AimTo assess orgasm occurrence during sexual activity across sexual orientation categories.Methods Data were collected by Internet questionnaire from 6,151 men and women (ages 21–65+ years) as part of a nationally representative sample of single individuals in the United States. Analyses were restricted to a subsample of 2,850 singles (1,497 men, 1,353 women) who had experienced sexual activity in the past 12 months.Main Outcome MeasuresParticipants reported their sex/gender, self-identified sexual orientation (heterosexual, gay/lesbian, bisexual), and what percentage of the time they experience orgasm when having sex with a familiar partner.ResultsMean occurrence rate for experiencing orgasm during sexual activity with a familiar partner was 62.9% among single women and 85.1% among single men, which was significantly different (F1,2848 = 370.6, P < 0.001, η2 = 0.12). For men, mean occurrence rate of orgasm did not vary by sexual orientation: heterosexual men 85.5%, gay men 84.7%, bisexual men 77.6% (F2,1494 = 2.67, P = 0.07, η2 = 0.004). For women, however, mean occurrence rate of orgasm varied significantly by sexual orientation: heterosexual women 61.6%, lesbian women 74.7%, bisexual women 58.0% (F2,1350 = 10.95, P < 0.001, η2 = 0.02). Lesbian women had a significantly higher probability of orgasm than did either heterosexual or bisexual women (P < 0.05).Conclusions Findings from this large dataset of U.S. singles suggest that women, regardless of sexual orientation, have less predictable, more varied orgasm experiences than do men and that for women, but not men, the likelihood of orgasm varies with sexual orientation. These findings demonstrate the need for further investigations into the comparative sexual experiences and sexual health outcomes of sexual minorities. Garcia JR, Lloyd EA, Wallen K, and Fisher HE. Variation in orgasm occurrence by sexual orientation in a sample of U.S. singles. J Sex Med **;**:**–**.
    Journal of Sexual Medicine 09/2014; · 3.51 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Opioid receptors are G protein-coupled receptors (GPCRs) that modulate brain function at all levels of neural integration, including autonomic, sensory, emotional and cognitive processing. Mu (MOR) and delta (DOR) opioid receptors functionally interact in vivo, but whether interactions occur at circuitry, cellular or molecular levels remains unsolved. To challenge the hypothesis of MOR/DOR heteromerization in the brain, we generated redMOR/greenDOR double knock-in mice and report dual receptor mapping throughout the nervous system. Data are organized as an interactive database offering an opioid receptor atlas with concomitant MOR/DOR visualization at subcellular resolution, accessible online. We also provide co-immunoprecipitation-based evidence for receptor heteromerization in these mice. In the forebrain, MOR and DOR are mainly detected in separate neurons, suggesting system-level interactions in high-order processing. In contrast, neuronal co-localization is detected in subcortical networks essential for survival involved in eating and sexual behaviors or perception and response to aversive stimuli. In addition, potential MOR/DOR intracellular interactions within the nociceptive pathway offer novel therapeutic perspectives.
    Brain Structure and Function 03/2014; · 7.84 Impact Factor

Full-text (2 Sources)

Download
143 Downloads
Available from
May 22, 2014