Toward an understanding of the cerebral substrates of woman's orgasm

Neuroelectric Correlates of Human Sexuality: A Review and Meta-Analysis

Many reviews on sexual arousal in humans focus on different brain imaging methods and behavioral observations. Although neurotransmission in the brain is mainly performed through electrochemical signals, there are no systematic reviews of the electrophysiological correlates of sexual arousal. We performed a systematic search on this subject and reviewed 255 studies including various electrophysiological methods. Our results show how neuroelectric signals have been used to investigate genital somatotopy as well as basic genital physiology during sexual arousal and how cortical electric signals have been recorded during orgasm. Moreover, experiments on the interactions of cognition and sexual arousal in healthy subjects and in individuals with abnormal sexual preferences were analyzed as well as case studies on sexual disturbances associated with diseases of the nervous system. In addition, 25 studies focusing on brain potentials during the interaction of cognition and sexual arousal were eligible for meta-analysis. The results showed significant effect sizes for specific brain potentials during sexual stimulation (P3: Cohen's d = 1.82, N = 300, LPP: Cohen's d = 2.30, N = 510) with high heterogeneity between the combined studies. Taken together, our review shows how neuroelectric methods can consistently differentiate sexual arousal from other emotional states.

Physical Pain as Pleasure: A Theoretical Perspective

Physical pain represents a common feature of Bondage and Discipline/Dominance and Submission/Sadism and Machochism (BDSM) activity. This article explores the literature accounting for how painful stimuli may be experienced as pleasurable among practitioners of BDSM, and contrasting this with how it is experienced as painful among non-BDSM individuals. We reviewed the available literature on pain and on BDSM, and used the findings to postulate a theory accounting for how painful stimuli are experienced as pleasurable. Our theory was then checked with BDSM practitioners. The emotional, physiological, and psychological elements of pain interact to facilitate the experience of pain as pleasure in BDSM. A multitude of interconnected factors was theorized to alter the experience of BDSM pain, including: neural networks, neurotransmitters, endogenous opioids and endocannabinoids, visual stimuli, environmental context, emotional state, volition and control, interpersonal connection, sexual arousal, and memories. The experience of pain in this context can bring about altered states of consciousness that may be similar to what occurs during mindfulness meditation. Through understanding the mechanisms by which pain may be experienced as pleasure, the role of pain in BDSM is demystified and, it is hoped, destigmatized.

Sexuality in women with endometriosis: a critical narrative review

Endometriosis is a chronic gynecological disease that generally affects young and sexually active women in different stages of their development and sexual life. Because endometriosis affects about 5-10% of women in reproductive age, it is possible to estimate that about 2-4% of those who are sexually active may suffer from sexual dysfunction caused by this disease. Surgical and pharmacological treatments of endometriosis can improve the patient's sexual function in the medium and long term, but not necessarily lead to a definitive resolution of the sexual issue. For this reason, the ideal treatment should be conducted by a multidisciplinary team, with the aim to improve overall sexual functioning and not only to reduce the painful symptoms during intercourse. In light of these considerations, the aim of this narrative review was to provide a general overview about the impact of endometriosis on sexuality of women affected and the effectiveness of surgical and pharmacological treatments in improving sexual function.

Validation of a Visual Analogue Scale to measure the subjective perception of orgasmic intensity in females: The Orgasmometer-F

The female orgasm represents one of the most complex functions in the field of human sexuality.

The conjunction of the anatomical, physiological, psycho-relational and socio-cultural components contributes to make the female orgasm still partly unclear. The female orgasmic experience, its correlates and the relation with sexual desire, arousal and lubrication as predictors are highly debated in scientific community. In this context, little is known about the impact of female sexual dysfunction (SD) on sexual pleasure expressed by subjective orgasmic intensity, and there are no suitable psychometric tools suited to investigate this dimension. Thus, we validate, in female subjects, a Visual Analogue Scale (VAS) that we named Orgasmometer-F, to verify if SD is accompanied by a lower perceived orgasmic intensity. A total of 526 women, recruited through a web-based platform and from sexological outpatient clinic, were enrolled in the study. They were divided into, on the basis of the Female Sexual Function Index (FSFI) score in two groups: 1) 112women suffering from SD, (SD Group); and 2) 414 sexually healthy women (Control Group). The participants were requested to fill out the Orgasmometer-F, recording orgasmic intensity on a Likert scale from 0 (absence of orgasmic intensity) to 10 (maximum orgasmic intensity experienced). Women with SD experienced significantly lower orgasmic intensity than controls, as measured by the Orgasmometer-F (p < 0.0001). Interestingly, masturbatory frequency was positively correlated with orgasmic intensity, as were the lubrication, orgasm and sexual satisfaction domains of the FSFI. The Orgasmometer-F was well understood, had a good test-retest reliability (ICC = 0.93) and a high AUC in differentiating between women with and without sexual dysfunction (AUC = 0.9; p < 0.0001). The ROC curve analysis showed that a cut-off <5 had 86.5% sensitivity (95% CI 82,8–89,6), 80.4% specificity (95% CI 71.8–87.3), 75.4% positive predictive value (PPV) and 89.5% negative predictive value (NPV). In conclusion, the Orgasmometer-F, a new psychometrically sound tool for measuring orgasmic intensity in female population, demonstrated that SD impair orgasmic intensity.

Sexual Disorders Caused by Antidepressants: Considerations in the Context of Brain Hemisphere Functions

All phases of normal sexual activity are under the control of the right hemisphere coupled with limbic structures, and depression is characterized by the functional insufficiency of this system. At the same time, those modern antidepressants that cause sexual disorders are activating the left hemisphere and determine its domination on the expense of the right one and disturb free and spontaneous emotional interrelationships, sexual behavior and pleasure. Those antidepressants that do not cause sexual dysfunction are not activating predominantly the left hemisphere structures and activate the limbic brain zones responsible for reward, reinforcement and emotional excitement.

Activation of sensory cortex by imagined genital stimulation: an fMRI analysis

Background

During the course of a previous study, our laboratory made a serendipitous finding that just thinking about genital stimulation resulted in brain activations that overlapped with, and differed from, those generated by physical genital stimulation.

Objective

This study extends our previous findings by further characterizing how the brain differentially processes physical ‘touch’ stimulation and ‘imagined’ stimulation.

Design

Eleven healthy women (age range 29–74) participated in an fMRI study of the brain response to imagined or actual tactile stimulation of the nipple and clitoris. Two additional conditions – imagined dildo self-stimulation and imagined speculum stimulation – were included to characterize the effects of erotic versus non-erotic imagery.

Results

Imagined and tactile self-stimulation of the nipple and clitoris each activated the paracentral lobule (the genital region of the primary sensory cortex) and the secondary somatosensory cortex. Imagined self-stimulation of the clitoris and nipple resulted in greater activation of the frontal pole and orbital frontal cortex compared to tactile self-stimulation of these two bodily regions. Tactile self-stimulation of the clitoris and nipple activated the cerebellum, primary somatosensory cortex (hand region), and premotor cortex more than the imagined stimulation of these body regions. Imagining dildo stimulation generated extensive brain activation in the genital sensory cortex, secondary somatosensory cortex, hippocampus, amygdala, insula, nucleus accumbens, and medial prefrontal cortex, whereas imagining speculum stimulation generated only minimal activation.

Conclusion

The present findings provide evidence of the potency of imagined stimulation of the genitals and that the following brain regions may participate in erogenous experience: primary and secondary sensory cortices, sensory-motor integration areas, limbic structures, and components of the ‘reward system’. In addition, these results suggest a mechanism by which some individuals may be able to generate orgasm by imagery in the absence of physical stimulation.

Do rats have orgasms?

BACKGROUND

Although humans experience orgasms with a degree of statistical regularity, they remain among the most enigmatic of sexual responses; difficult to define and even more difficult to study empirically. The question of whether animals experience orgasms is hampered by similar lack of definition and the additional necessity of making inferences from behavioral responses.

METHOD

Here we define three behavioral criteria, based on dimensions of the subjective experience of human orgasms described by Mah and Binik, to infer orgasm-like responses (OLRs) in other species: 1) physiological criteria that include pelvic floor and anal muscle contractions that stimulate seminal emission and/or ejaculation in the male, or that stimulate uterine and cervical contractions in the female; 2) short-term behavioral changes that reflect immediate awareness of a pleasurable hedonic reward state during copulation; and 3) long-term behavioral changes that depend on the reward state induced by the OLR, including sexual satiety, the strengthening of patterns of sexual arousal and desire in subsequent copulations, and the generation of conditioned place and partner preferences for contextual and partner-related cues associated with the reward state. We then examine whether physiological and behavioral data from observations of male and female rats during copulation, and in sexually-conditioned place- and partner-preference paradigms, are consistent with these criteria.

RESULTS

Both male and female rats display behavioral patterns consistent with OLRs.

CONCLUSIONS

The ability to infer OLRs in rats offers new possibilities to study the phenomenon in neurobiological and molecular detail, and to provide both comparative and translational perspectives that would be useful for both basic and clinical research.

Sexual function in endometriosis patients and their partners: effect of the disease and consequences of treatment

BACKGROUND

Sexual function is an important aspect of health and quality of life and is influenced by both medical conditions and health-care interventions, especially when gynecologic disorders are involved. Coital pain is among the main factors that affect sexual functioning, and this symptom is reported by almost half of women suffering from endometriosis. However, sexuality is a complex phenomenon driven by social, psychological and biological/hormonal factors and the presence of endometriosis might further affect domains of sexual function and the quality of a sexual relationship.

OBJECTIVE AND RATIONALE

The objective of this report is to review the current state of knowledge on the impact that endometriosis and its treatments have on the sexual function of women and their sexual partners.

SEARCH METHODS

A systematic literature search was performed to identify studies evaluating sexual function in endometriosis patients, and a narrative analysis of results is presented. The review discusses relevant quantitative and qualitative studies analyzing the effect of endometriosis and its hormonal and surgical treatments on measures of sexual function and quality of sexual relationship.

OUTCOMES

Endometriosis negatively affects different domains of sexual function, and the presence of dyspareunia is not the only determinant of sexual health in these women. Chronic pelvic pain, advanced stages of disease and the presence of physical and mental comorbidities affect sexual function, as well as personality traits and women's expectations. Although a number of studies have evaluated the effect of surgery and hormonal treatment on deep dyspareunia, overall sexual function and quality of the relationship with the partner are often under-investigated.

WIDER IMPLICATIONS

Multiple clinical and personal determinants affect sexual function in women with endometriosis, with potentially negative consequences on the sexual function of partners and quality of the relationship. Additional prospective and longitudinal investigations are warranted using specific instruments to analyze biopsychosocial variables of sexual pain in endometriosis patients and the effects that actual treatments have on measures of quality of sexual function and relationship.

‘Birthgasm’

Childbirth is a fundamental component of a woman’s sexual cycle. The sexuality of childbirth is not well recognized in Western society despite research showing that some women experience orgasm(s) during labor and childbirth. Current thinking supports the view that labor and childbirth are perceived to be physically painful events, and more women are relying on medical interventions for pain relief in labor. This review explores the potential of orgasm as a mode of pain relief in childbirth and outlines the physiological explanations for its occurrence. Potential barriers to sexual expression during childbirth and labor, including the influence of deeply held cultural beliefs about sexuality, the importance of privacy and intimacy in facilitating orgasmic birth experiences, and the value of including prospective fathers in the birthing experience, are discussed. The role of midwives and their perceptions of the use of complementary and alternative therapies for pain relief in labor are examined. While there are indications of widespread use of complementary and alternative therapies such as hydrotherapy, herbal remedies, and breathing techniques for pain relief in childbirth, orgasm was not among those mentioned. Lack of recognition of the sexuality of childbirth, despite findings that orgasm can attenuate the effects of labor pain, suggests the need for greater awareness among expectant parents, educators, and health professionals of the potential of orgasm as a means of pain relief in childbirth.

The pharmacology of the human female orgasm - its biological and physiological backgrounds

The female orgasm has been examined over the years by numerous scientific disciplines yet it still has many secrets to be disclosed. Because its physiology, especially its neurophysiology, is sparingly understood its pharmacology is necessarily limited based mainly on the side effects of drugs. Few published studies have used a placebo group as controls. The paucity of focussed studies is well illustrated by the fact that there still is no approved medication to treat female orgasmic dysfunction. The present brief overview examines the most important aspects of its biology and especially its physiology highlighting the many questions that need answering if we are to have a comprehensive pharmacology of the female orgasm.

A functional architecture of the human brain: emerging insights from the science of emotion

The 'faculty psychology' approach to the mind, which attempts to explain mental function in terms of categories that reflect modular 'faculties', such as emotions, cognitions, and perceptions, has dominated research into the mind and its physical correlates. In this paper, we argue that brain organization does not respect the commonsense categories belonging to the faculty psychology approach. We review recent research from the science of emotion demonstrating that the human brain contains broadly distributed functional networks that can each be re-described as basic psychological operations that interact to produce a range of mental states, including, but not limited to, anger, sadness, fear, disgust, and so on. When compared to the faculty psychology approach, this 'constructionist' approach provides an alternative functional architecture to guide the design and interpretation of experiments in cognitive neuroscience.

The human sexual response cycle: brain imaging evidence linking sex to other pleasures

Sexual behavior is critical to species survival, yet comparatively little is known about the neural mechanisms in the human brain. Here we systematically review the existing human brain imaging literature on sexual behavior and show that the functional neuroanatomy of sexual behavior is comparable to that involved in processing other rewarding stimuli. Sexual behavior clearly follows the established principles and phases for wanting, liking and satiety involved in the pleasure cycle of other rewards. The studies have uncovered the brain networks involved in sexual wanting or motivation/anticipation, as well as sexual liking or arousal/consummation, while there is very little data on sexual satiety or post-orgasmic refractory period. Human sexual behavior also interacts with other pleasures, most notably social interaction and high arousal states. We discuss the changes in the underlying brain networks supporting sexual behavior in the context of the pleasure cycle, the changes to this cycle over the individual's life-time and the interactions between them. Overall, it is clear from the data that the functional neuroanatomy of sex is very similar to that of other pleasures and that it is unlikely that there is anything special about the brain mechanisms and networks underlying sex.

Pain and emotion: a biopsychosocial review of recent research

OBJECTIVE AND METHOD

Research on emotion and pain has burgeoned. We review the last decade's literature, focusing on links between emotional processes and persistent pain.

RESULTS

Neurobiological research documents the neural processes that distinguish affective from sensory pain dimensions, link emotion and pain, and generate central nervous system pain sensitization. Psychological research demonstrates that greater pain is related to emotional stress and limited emotional awareness, expression, and processing. Social research shows the potential importance of emotional communication, empathy, attachment, and rejection.

CONCLUSIONS

Emotions are integral to the conceptualization, assessment, and treatment of persistent pain. Research should clarify when to eliminate or attenuate negative emotions, and when to access, experience, and express them. Theory and practice should integrate emotion into cognitive-behavioral models of persistent pain.

Opposed hemispheric specializations for human hypersexuality and orgasm?

With a multiple case report analysis we demonstrate that hypersexuality more often results from right hemisphere (RH) (n=26) than left hemisphere (LH) (n=7) lesions, possibly because of LH release after the RH lesion, and that ictal orgasm more often occurs in patients with right-sided (n=23) than left-sided (n=8) seizure foci, with the symptom probably resulting from RH activation. The LH may be specialized for increasing sexual tension, whereas the RH may be specialized for release of this tension (orgasm), the former being catabolic and the latter anabolic. Several other interpretations of the findings are also discussed.

Correlation between insula activation and self-reported quality of orgasm in women

Current multidimensional models of women's sexual function acknowledge the implicit impact of psychosocial factors on women's sexual function. Interaction between human sexual function and intensity of love has been also assumed, even if love is not an absolute condition. Yet, whereas great insights have been made in understanding the central mechanisms of the peripheral manifestations of women's sexual response, including orgasm, the cerebral correlates sustaining the interaction between women's sexual satisfaction and the unconscious role of the partner in this interpersonal experience remain unknown. Using functional imaging, we assessed brain activity elicited when 29 healthy female volunteers were unconsciously exposed to the subliminal presentation of their significant partner's name (a task known to elicit a partner-related neural network) and correlated it with individual scores obtained from different sexual dimensions: self-reported partnered orgasm quality (ease, satisfaction, frequency), love intensity and emotional closeness with that partner. Behavioral results identified a correlation between love and self-reported partnered orgasm quality. The more women were in love/emotionally close to their partner, the more they tended to report being satisfied with the quality of their partnered orgasm. However, no relationship was found between intensity of love and partnered orgasm frequency. Neuroimaging data expanded these behavioral results by demonstrating the involvement of a specific left-lateralized insula focus of neural activity correlating with orgasm scores, irrespective of dimension (frequency, ease, satisfaction). In contrast, intensity of being in love was correlated with a network involving the angular gyrus. These findings strongly suggest that intimate and sexual relationships are sustained by partly different mechanisms, even if they share some emotional-related mechanisms. The critical correlation between self-reports of orgasm quality and activation of the left anterior insula, a part of the partner-related neural network known to play a pivotal role in somatic processes, suggests the importance of somatic information in the integration of sexual experience. On the other hand, the correlation between activation of the angular gyrus and love intensity reinforces the assumption that the representation of love calls for higher order cognitive levels, such as those related to the generation of abstract concepts. By highlighting the specific role of the anterior insula in the way women integrate components of physical satisfaction in the context of an intimate relationship with a partner, the current findings take a step in the understanding of a woman's sexual pleasure.