Subcortical BOLD responses during visual sexual stimulation vary as a function of implicit porn associations in women

The Influence of Subjective Sexual Arousal and Disgust on Pain

Current models propose that inhibited sexual arousal is a key component in maintaining sexual pain in women with Genito-Pelvic Pain/Penetration Disorder. It thus follows that enhancing sexual arousal may be an effective strategy to modulate pain, but this effect has not been successfully demonstrated with women, although it has been successful with men. This study built on previous works and examined if the pain-killing effect of sexual arousal might have been undermined by concurrently-elicited disgust. We tested whether women experience disgust as well as sexual arousal when viewing sex stimuli, and whether disgust has an exacerbating effect on pain. Female participants (N = 164) were randomly distributed to watch a porn, disgust, or neutral train-ride film. A cold pressor test (CPT) was utilized to induce pain at the same time that participants viewed their respective film. Pain was indexed by the duration that participants kept their hand in the cold water, and by self-reported pain intensity at the time they quit the CPT. The results showed no differences in pain across conditions. The sex stimulus elicited substantial disgust as well as sexual arousal, and there was a negative correlation between the two emotions. Disgust was not found to increase pain compared to both the neutral and sex conditions. Thus, the findings provide no support for a pain-modulatory effect of subjective sexual arousal on pain in women. This might, however, be due to the sex stimulus having elicited an ambivalent state between an appetitive and aversive emotion concurrently.

Affective neuroscience: applications for sexual medicine research and clinical practice

INTRODUCTION

Affective neuroscience is the study of the brain substrates of emotional, embodied experiences. Affective neuroscience theory (ANT) is based on experimental evidence that all mammals are hardwired with 7 primary subcortical emotional operating systems, or "core emotions," that have overlapping but distinct circuits buried in the deep, ancient parts of the brain. Imbalances in the 7 core emotions can affect multiple aspects of the individual's psychosocial well-being (eg, depression, anxiety, substance abuse). Here, we propose that core emotions can also influence sexual function and, specifically, that imbalances in core emotions are the bridge connecting psychiatric symptoms (eg, anhedonia) to sexual dysfunction (eg, anorgasmia).

OBJECTIVES

In this targeted review and commentary, we outline potential connections between ANT and sexual medicine research and clinical practice. We summarize ANT by defining the 3-level BrainMind and core emotions; examining how they relate to personality, behavior, and mental health; and determining the implications for sexual health research and clinical practice.

METHODS

A targeted literature review was conducted. Case studies were adapted from client files and clinician interviews and then anonymized.

RESULTS

We propose a novel organizational schema for implementing affective balance therapies for sexual dysfunction, which integrate psychoeducational, somatic, and cognitive therapeutic approaches under the ANT framework. We provide 3 patient case studies (anorgasmia, hypersexuality, spinal cord injury) outlining the implementation of this approach and patient outcomes.

CONCLUSION

ANT has practical translational applications in sexual health research and clinical practice. By integrating our understanding of the role of core emotions in human sexuality, clinicians can better tailor treatments to address sexual dysfunction.

Bidirectional relationship between sexual arousal and (sex-related) disgust

Sexual stimuli provoke both sexual arousal and disgust, and the coaction between these emotions determines sexually behavioral outcomes. The current research includes two experiments to explore the bidirectional relationship between sexual arousal toward erotic stimuli and disgust induced by sexual body fluids. Study 1 presented 234 participants (117 women) with sexual body (vs. neutral) fluids followed by erotic stimuli, and Study 2 presented 235 participants (117 women) with erotic (vs. neutral) videos followed by sexual body fluids (and a non-sex-related stimulus). Study 1 showed that exposure to sexual body fluids reduced sexual arousal and the likelihood of sexual engagement toward erotic stimuli in participants with high sexual disgust sensitivity but increased sexual arousal and the likelihood of sexual engagement in participants with low sexual disgust sensitivity, while Study 2 suggested that men exposed to erotic (vs. neutral) stimuli reported lower disgust, stronger sexual arousal state, and higher willingness to interact with the sexual body fluids. There was no relationship between subjective feelings of sexual arousal and disgust in these experiments, while the balance of sexual arousal and disgust toward sexual body fluids and erotic stimuli had a positive association. Also, exposure to erotic stimuli had no effect on reactions to generally disgusting stimulus, but feelings of sexual arousal toward erotic stimuli were positively associated with disgust induced by generally disgusting fluid. These findings suggest that Behavior Immune System regulates disgust to establish a balance between benefit and cost related to sex as well as provide insight into the process underlying sexual dysfunctions.

The influence of sexual arousal on subjective pain intensity during a cold pressor test in women

BACKGROUND & OBJECTIVES

Pain can be significantly lessened by sex/orgasm, likely due to the release of endorphins during sex, considered potent analgesics. The evidence suggests that endorphins are also present during sexual arousal (that is, prior to sex/orgasm). It follows then that pain can be modulated during sexual arousal, independent of sex/orgasm, too. Accordingly, sexual arousal induced by erotic slides has been demonstrated to lessen pain in men, but not in women. One explanation could be that for women, the erotic slides were not potent enough to elicit a lasting primed state of sexual arousal by the time pain was induced. Thus, the current study aims to optimize the means of inducing a potent state of sexual arousal and subsequently examine the potentially analgesic influence of sexual arousal on pain in women. As a subsidiary aim, the study also assesses whether the anticipated analgesic effect of sexual arousal would be stronger than that of distraction or generalized (non-sexual) arousal.

METHODS

Female participants (N = 151) were randomly distributed across four conditions: sexual arousal, generalized arousal, distraction, neutral. Mild pain was induced using a cold pressor while participants were concurrently exposed to film stimuli (pornographic, exciting, distracting, neutral) to induce the targeted emotional states. A visual analogue scale was utilized to measure the subjective level of pain perceived by the participants.

RESULTS

Sexual arousal did not reduce subjective pain. Generalized arousal and distraction did not result in stronger analgesic effects than the neutral condition.

CONCLUSION

The present findings do not support the hypothesis that sexual arousal alone modulates subjective pain in women. This might be due to the possibility that genital stimulation and/or orgasm are key in pain reduction, or, that feelings of disgust may inadvertently have been induced by the pornographic stimulus and interfered with sexual arousal in influencing pain.

The Brain Activation-Based Sexual Image Classifier (BASIC): A Sensitive and Specific fMRI Activity Pattern for Sexual Image Processing

Previous studies suggest there is a complex relationship between sexual and general affective stimulus processing, which varies across individuals and situations. We examined whether sexual and general affective processing can be distinguished at the brain level. In addition, we explored to what degree possible distinctions are generalizable across individuals and different types of sexual stimuli, and whether they are limited to the engagement of lower-level processes, such as the detection of visual features. Data on sexual images, nonsexual positive and negative images, and neutral images from Wehrum et al. (2013) (N = 100) were reanalyzed using multivariate support vector machine models to create the brain activation-based sexual image classifier (BASIC) model. This model was tested for sensitivity, specificity, and generalizability in cross-validation (N = 100) and an independent test cohort (N = 18; Kragel et al. 2019). The BASIC model showed highly accurate performance (94–100%) in classifying sexual versus neutral or nonsexual affective images in both datasets with forced choice tests. Virtual lesions and tests of individual large-scale networks (e.g., visual or attention networks) show that individual networks are neither necessary nor sufficient to classify sexual versus nonsexual stimulus processing. Thus, responses to sexual images are distributed across brain systems.

Specific factors and methodological decisions influencing brain responses to sexual stimuli in women

Most of the neuroimaging studies on sexual behavior have been conducted with male participants, leading to men-based models of sexual arousal. Here, possible factors and methodological decisions that might influence brain responses to sexual stimuli, specifically for the inclusion of women, will be reviewed. Based on this review, we suggest that future studies consider the following factors: menstrual phase, hormonal contraception use, history of sexual or psychiatric disorders or diseases, and medication use. Moreover, when researching sexual arousal, we suggest future studies assess sexual orientation and preferences, that women should select visual sexual stimuli, and a longer duration than commonly used. This review is thought to represent a useful guideline for future research in sexual arousal, which hopefully will lead to a higher inclusion of women and therefore more accurate neurobiological models of sexual arousal.

Understanding heterosexual women's erotic flexibility: the role of attention in sexual evaluations and neural responses to sexual stimuli

Many women experience desires, arousal and behavior that run counter to their sexual orientation (orientation inconsistent, 'OI'). Are such OI sexual experiences cognitively and neurobiologically distinct from those that are consistent with one's sexual orientation (orientation consistent, 'OC')? To address this question, we employed a mindful attention intervention-aimed at reducing judgment and enhancing somatosensory attention-to examine the underlying attentional and neurobiological processes of OC and OI sexual stimuli among predominantly heterosexual women. Women exhibited greater neural activity in response to OC, compared to OI, sexual stimuli in regions associated with implicit visual processing, volitional appraisal and attention. In contrast, women exhibited greater neural activity to OI, relative to OC, sexual stimuli in regions associated with complex visual processing and attentional shifting. Mindfully attending to OC sexual stimuli reduced distraction, amplified women's evaluations of OC stimuli as sexually arousing and deactivated the superior cerebellum. In contrast, mindfully attending to OI sexual stimuli amplified distraction, decreased women's evaluations of OI stimuli as sexually arousing and augmented parietal and temporo-occipital activity. Results of the current study constrain hypotheses of female erotic flexibility, suggesting that sexual orientation may be maintained by differences in attentional processing that cannot be voluntarily altered.

Basal ganglia lateralization in different types of reward

Reward processing is a fundamental human activity. The basal ganglia are recognized for their role in reward processes; however, specific roles of the different nuclei (e.g., nucleus accumbens, caudate, putamen and globus pallidus) remain unclear. Using quantitative meta-analyses we assessed whole-brain and basal ganglia specific contributions to money, erotic, and food reward processing. We analyzed data from 190 fMRI studies which reported stereotaxic coordinates of whole-brain, within-group results from healthy adult participants. Results showed concordance in overlapping and distinct cortical and sub-cortical brain regions as a function of reward type. Common to all reward types was concordance in basal ganglia nuclei, with distinct differences in hemispheric dominance and spatial extent in response to the different reward types. Food reward processing favored the right hemisphere; erotic rewards favored the right lateral globus pallidus and left caudate body. Money rewards engaged the basal ganglia bilaterally including its most anterior part, nucleus accumbens. We conclude by proposing a model of common reward processing in the basal ganglia and separate models for money, erotic, and food rewards.

Up-regulating Sexual Arousal and Down-regulating Disgust while Watching Pornography: Effects on Sexual Arousal and Disgust

Sexual response occurs when sexual excitatory factors outweigh inhibitory factors. Problems with sexual arousal may occur when sexual excitation is too low and/or inhibitory influences such as feelings of disgust are too strong. To explore interventions that may help overcome decreased sexual responding, we examined if sexual responding could be amplified by instructions to up-regulate sexual arousal and/or down-regulate disgust. Women with no sexual difficulties (N = 255; µ_age = 20.55; SD = 2.23) were randomly assigned to a sexual arousal up-regulation, disgust down-regulation, or passive control condition. Participants were instructed to use the assigned regulation strategy while viewing pornography. To prevent floor effects due to low disgust responsivity in a non-clinical sample, half of the participants were presented with a prime that was designed to make the contaminating properties of sex more salient. Instruction to up-regulate sexual arousal successfully enhanced feelings of sexual arousal in the unprimed group, yet the increase in sexual arousal was not paralleled by reductions in feelings of disgust. Instruction to down-regulate disgust successfully decreased disgust; however, this decrease was not paralleled by increases in sexual arousal. Overall, findings indicate that emotion regulation techniques could facilitate affective control in sexual contexts.

Male Urogenital System Mapped Onto the Sensory Cortex: Functional Magnetic Resonance Imaging Evidence

INTRODUCTION

The projection of the human male urogenital system onto the paracentral lobule has not previously been mapped comprehensively.

AIM

To map specific urogenital structures onto the primary somatosensory cortex toward a better understanding of sexual response in men.

METHODS

Using functional magnetic resonance imaging, we mapped primary somatosensory cortical responses to self-stimulation of the penis shaft, glans, testicles, scrotum, rectum, urethra, prostate, perineum, and nipple. We further compared neural response with erotic and prosaic touch of the penile shaft.

MAIN OUTCOME MEASURE

We identified the primary mapping site of urogenital structures on the paracentral lobule and identified networks involved in perceiving touch as erotic.

RESULTS

We mapped sites on the primary somatosensory cortex to which components of the urogenital structures project in men. Evidence is provided that penile cutaneous projection is different from deep penile projection. Similar to a prior report in women, we show that the nipple projects to the same somatosensory cortical region as the genitals. Evidence of differential representation of erotic and nonerotic genital self-stimulation is also provided, the former activating sensory networks other than the primary sensory cortex, indicating a role of "top-down" activity in erotic response.

CLINICAL IMPLICATIONS

We map primary sites of projection of urogenital structures to the primary somatosensory cortex and differentiate cortical sites of erotic from nonerotic genital self-stimulation.

STRENGTH & LIMITATIONS

To our knowledge, this is the first comprehensive mapping onto the primary somatosensory cortex of the projection of the components of the urogenital system in men and the difference in cortical activation in response to erotic vs nonerotic self-stimulation. The nipple was found to project to the same cortical region as the genitals. Evidence is provided that superficial and deep penile stimulation project differentially to the cortex, suggesting that sensory innervation of the penis is provided by more than the (pudendal) dorsal nerve.

CONCLUSION

This study reconciles prior apparently conflicting findings and offers a comprehensive mapping of male genital components to the paracentral lobule. We provide evidence of differential projection of light touch vs pressure applied to the penile shaft, suggesting differential innervation of its superficial, vs deep structure. Similar to the response in women, we found nipple projection to genital areas of the paracentral lobule. We also provide evidence of differential representation of erotic and nonerotic genital self-stimulation, the former activating sensory networks other than the primary sensory cortex, indicating a role of top-down activity in erotic response. Allen K, Wise N, Frangos E, et al. Male Urogenital System Mapped Onto the Sensory Cortex: Functional Magnetic Resonance Imaging Evidence. J Sex Med 2020;17:603-613.

Cognitive mechanisms of disgust in the development and maintenance of psychopathology: A qualitative review and synthesis

A growing body of research has implicated disgust in various psychopathologies, especially anxiety-related disorders. Although the observed role of disgust in many disorders is robust, the mechanisms that may explain this role are unclear. Cutting-edge research in cognitive science has the potential to elucidate such mechanisms and consequently improve our understanding of how disgust contributes to the etiology and maintenance of psychopathology. In this qualitative review, we systematically assess cognitive bias mechanisms that have been linked to disgust and its disorders. This review suggests that disgust-related biases may be observed in memory, interpretation, judgment of expectancies, and attention, as well as at implicit levels. Of these cognitive domains, the most robust bias appears to be observed at the level of attention. However, reliable moderators of attentional biases for disgust have not yet been identified, and this bias has not been systematically linked to other levels of analysis. Despite these limitations, the available research indicates that attentional avoidance rather than orienting or maintenance may be the most characteristic of disgust. Attentional avoidance of disgust may have important implications for etiological and treatment models of disorders characterized by excessive disgust reactions. The implications for advancing such models are discussed in the context of a combined cognitive bias hypothesis.

Brain Imaging of Human Sexual Response: Recent Developments and Future Directions

PURPOSE OF REVIEW

The purpose of this study is to provide a comprehensive summary of the latest developments in the experimental brain study of human sexuality, focusing on brain connectivity during the sexual response.

RECENT FINDINGS

Stable patterns of brain activation have been established for different phases of the sexual response, especially with regard to the wanting phase, and changes in these patterns can be linked to sexual response variations, including sexual dysfunctions. From this solid basis, connectivity studies of the human sexual response have begun to add a deeper understanding of the brain network function and structure involved.

SUMMARY

The study of "sexual" brain connectivity is still very young. Yet, by approaching the brain as a connected organ, the essence of brain function is captured much more accurately, increasing the likelihood of finding useful biomarkers and targets for intervention in sexual dysfunction.

Affective and Autonomic Responses to Erotic Images: Evidence of Disgust-Based Mechanisms in Female Sexual Interest/Arousal Disorder

Disgust has recently been implicated in the development and maintenance of female sexual dysfunction, yet most empirical studies have been conducted with a sexually healthy sample. The current study contributes to the literature by expanding the application of a disgust model of sexual functioning to a clinically relevant sample of women with low sexual desire/arousal and accompanying sexual distress. Young women (mean age = 19.12 years) with psychometrically defined sexual dysfunction (i.e., female sexual interest/arousal disorder [FSIAD] group) and a healthy control group were compared in their affective (i.e., facial electromyography [EMG] and self-report) and autonomic (i.e., heart rate and electrodermal activity) responses to disgusting, erotic, positive, and neutral images. Significant differences were predicted in responses to erotic images only. Specifically, it was hypothesized that the FSIAD group would display affective and autonomic responses consistent with a disgust response, while responses from the control group would align with a general appetitive response. Results largely supported study hypotheses. The FSIAD group displayed significantly greater negative facial affect, reported more subjective disgust, and recorded greater heart rate deceleration than the control group in response to erotic stimuli. Greater subjective disgust response corresponded with more sexual avoidance behavior. Planned follow-up analyses explored correlates of subjective disgust responses.

The Physiology of Female Sexual Function and the Pathophysiology of Female Sexual Dysfunction (Committee 13A)

INTRODUCTION

The article consists of six sections written by separate authors that review female genital anatomy, the physiology of female sexual function, and the pathophysiology of female sexual dysfunction but excluding hormonal aspects.

AIM

To review the physiology of female sexual function and the pathophysiology of female sexual dysfunction especially since 2010 and to make specific recommendations according to the Oxford Centre for evidence based medicine (2009) "levels of evidence" wherever relevant.

CONCLUSION

Recommendations were made for particular studies to be undertaken especially in controversial aspects in all six sections of the reviewed topics. Despite numerous laboratory assessments of female sexual function, genital assessments alone appear insufficient to characterise fully the complete sexual response.

The neural basis of sex differences in sexual behavior: A quantitative meta-analysis

Sexuality as to its etymology presupposes the duality of sexes. Using quantitative neuroimaging meta-analyses, we demonstrate robust sex differences in the neural processing of sexual stimuli in thalamus, hypothalamus, and basal ganglia. In a narrative review, we show how these relate to the well-established sex differences on the behavioral level. More specifically, we describe the neural bases of known poor agreement between self-reported and genital measures of female sexual arousal, of previously proposed male proneness to affective sexual conditioning, as well as hints of unconscious activation of bonding mechanisms during sexual stimulation in women. In summary, our meta-analytic review demonstrates that neurofunctional sex differences during sexual stimulation can account for well-established sex differences in sexual behavior.

Visual Sexual Stimuli-Cue or Reward? A Perspective for Interpreting Brain Imaging Findings on Human Sexual Behaviors

There is an increasing number of neuroimaging studies using visual sexual stimuli (VSS), especially within the emerging field of research on compulsive sexual behaviors (CSB). A central question in this field is whether behaviors such as excessive pornography consumption share common brain mechanisms with widely studied substance and behavioral addictions. Depending on how VSS are conceptualized, different predictions can be formulated within the frameworks of Reinforcement Learning or Incentive Salience Theory, where a crucial distinction is made between conditioned and unconditioned stimuli (related to reward anticipation vs. reward consumption, respectively). Surveying 40 recent human neuroimaging studies we show existing ambiguity about the conceptualization of VSS. Therefore, we feel that it is important to address the question of whether VSS should be considered as conditioned stimuli (cue) or unconditioned stimuli (reward). Here we present our own perspective, which is that in most laboratory settings VSS play a role of reward, as evidenced by: (1) experience of pleasure while watching VSS, possibly accompanied by genital reaction; (2) reward-related brain activity correlated with these pleasurable feelings in response to VSS; (3) a willingness to exert effort to view VSS similarly as for other rewarding stimuli such as money; and (4) conditioning for cues predictive of VSS. We hope that this perspective article will initiate a scientific discussion on this important and overlooked topic and increase attention for appropriate interpretations of results of human neuroimaging studies using VSS.

A neural circuit encoding sexual preference in humans

Sexual preference determines mate choice for reproduction and hence guarantees conservation of species in mammals. Despite this fundamental role in human behavior, current knowledge on its target-specific neurofunctional substrate is based on lesion studies and therefore limited. We used meta-analytic remodeling of neuroimaging data from 364 human subjects with diverse sexual interests during sexual stimulation to quantify neural regions associated with sexual preference manipulations. We found that sexual preference is encoded by four phylogenetically old, subcortical brain structures. More specifically, sexual preference is controlled by the anterior and preoptic area of the hypothalamus, the anterior and mediodorsal thalamus, the septal area, and the perirhinal parahippocampus including the dentate gyrus. In contrast, sexual non-preference is regulated by the substantia innominata. We anticipate the identification of a core neural circuit for sexual preferences to be a starting point for further sophisticated investigations into the neural principles of sexual behavior and particularly of its aberrations.

Animal Models for the Study of Female Sexual Dysfunction

INTRODUCTION

Significant progress has been made in elucidating the physiological and pharmacological mechanisms of female sexual function through preclinical animal research. The continued development of animal models is vital for the understanding and treatment of the many diverse disorders that occur in women.

AIM

To provide an updated review of the experimental models evaluating female sexual function that may be useful for clinical translation.

METHODS

Review of English written, peer-reviewed literature, primarily from 2000 to 2012, that described studies on female sexual behavior related to motivation, arousal, physiological monitoring of genital function and urogenital pain.

MAIN OUTCOMES MEASURES

Analysis of supporting evidence for the suitability of the animal model to provide measurable indices related to desire, arousal, reward, orgasm, and pelvic pain.

RESULTS

The development of female animal models has provided important insights in the peripheral and central processes regulating sexual function. Behavioral models of sexual desire, motivation, and reward are well developed. Central arousal and orgasmic responses are less well understood, compared with the physiological changes associated with genital arousal. Models of nociception are useful for replicating symptoms and identifying the neurobiological pathways involved. While in some cases translation to women correlates with the findings in animals, the requirement of circulating hormones for sexual receptivity in rodents and the multifactorial nature of women's sexual function requires better designed studies and careful analysis. The current models have studied sexual dysfunction or pelvic pain in isolation; combining these aspects would help to elucidate interactions of the pathophysiology of pain and sexual dysfunction.

CONCLUSIONS

Basic research in animals has been vital for understanding the anatomy, neurobiology, and physiological mechanisms underlying sexual function and urogenital pain. These models are important for understanding the etiology of female sexual function and for future development of pharmacological treatments for sexual dysfunctions with or without pain. Marson L, Giamberardino MA, Costantini R, Czakanski P, and Wesselmann U. Animal models for the study of female sexual dysfunction. Sex Med Rev 2013;1:108-122.

Excessive disgust caused by brain lesions or temporary inactivations: mapping hotspots of the nucleus accumbens and ventral pallidum

Disgust is a prototypical type of negative affect. In animal models of excessive disgust, only a few brain sites are known in which localized dysfunction (lesions or neural inactivations) can induce intense 'disgust reactions' (e.g. gapes) to a normally pleasant sensation such as sweetness. Here, we aimed to map forebrain candidates more precisely, to identify where either local neuronal damage (excitotoxin lesions) or local pharmacological inactivation (muscimol/baclofen microinjections) caused rats to show excessive sensory disgust reactions to sucrose. Our study compared subregions of the nucleus accumbens shell, ventral pallidum, lateral hypothalamus, and adjacent extended amygdala. The results indicated that the posterior half of the ventral pallidum was the only forebrain site where intense sensory disgust gapes in response to sucrose were induced by both lesions and temporary inactivations (this site was previously identified as a hedonic hotspot for enhancements of sweetness 'liking'). By comparison, for the nucleus accumbens, temporary GABA inactivations in the caudal half of the medial shell also generated sensory disgust, but lesions never did at any site. Furthermore, even inactivations failed to induce disgust in the rostral half of the accumbens shell (which also contains a hedonic hotspot). In other structures, neither lesions nor inactivations induced disgust as long as the posterior ventral pallidum remained spared. We conclude that the posterior ventral pallidum is an especially crucial hotspot for producing excessive sensory disgust by local pharmacological/lesion dysfunction. By comparison, the nucleus accumbens appears to segregate sites for pharmacological disgust induction and hedonic enhancement into separate posterior and rostral halves of the medial shell.

Brain networks during free viewing of complex erotic movie: new insights on psychogenic erectile dysfunction

Psychogenic erectile dysfunction (ED) is defined as a male sexual dysfunction characterized by a persistent or recurrent inability to attain adequate penile erection due predominantly or exclusively to psychological or interpersonal factors. Previous fMRI studies were based on the common occurrence in the male sexual behaviour represented by the sexual arousal and penile erection related to viewing of erotic movies. However, there is no experimental evidence of altered brain networks in psychogenic ED patients (EDp). Some studies showed that fMRI activity collected during non sexual movie viewing can be analyzed in a reliable manner with independent component analysis (ICA) and that the resulting brain networks are consistent with previous resting state neuroimaging studies. In the present study, we investigated the modification of the brain networks in EDp compared to healthy controls (HC), using whole-brain fMRI during free viewing of an erotic video clip. Sixteen EDp and nineteen HC were recruited after RigiScan evaluation, psychiatric, and general medical evaluations. The performed ICA showed that visual network (VN), default-mode network (DMN), fronto-parietal network (FPN) and salience network (SN) were spatially consistent across EDp and HC. However, between-group differences in functional connectivity were observed in the DMN and in the SN. In the DMN, EDp showed decreased connectivity values in the inferior parietal lobes, posterior cingulate cortex and medial prefrontal cortex, whereas in the SN decreased and increased connectivity was observed in the right insula and in the anterior cingulate cortex respectively. The decreased levels of intrinsic functional connectivity principally involved the subsystem of DMN relevant for the self relevant mental simulation that concerns remembering of past experiences, thinking to the future and conceiving the viewpoint of the other’s actions. Moreover, the between group differences in the SN nodes suggested a decreased recognition of autonomical and sexual arousal changes in EDp.

Brain processing of visual stimuli representing sexual penetration versus core and animal-reminder disgust in women with lifelong vaginismus

It has been proposed that disgust evolved to protect humans from contamination. Through eliciting the overwhelming urge to withdraw from the disgusting stimuli, it would facilitate avoidance of contact with pathogens. The physical proximity implied in sexual intercourse provides ample opportunity for contamination and may thus set the stage for eliciting pathogen disgust. Building on this, it has been argued that the involuntary muscle contraction characteristic of vaginismus (i.e., inability to have vaginal penetration) may be elicited by the prospect of penetration by potential contaminants. To further investigate this disgust-based interpretation of vaginismus (in DSM-5 classified as a Genito-Pelvic Pain/Penetration Disorder, GPPPD) we used functional magnetic resonance imaging (fMRI) to examine if women with vaginismus (n = 21) show relatively strong convergence in their brain responses towards sexual penetration- and disgust-related pictures compared to sexually asymptomatic women (n = 21) and women suffering from vulvar pain (dyspareunia/also classified as GPPPD in the DSM-5, n = 21). At the subjective level, both clinical groups rated penetration stimuli as more disgusting than asymptomatic women. However, the brain responses to penetration stimuli did not differ between groups. In addition, there was considerable conjoint brain activity in response to penetration and disgust pictures, which yield for both animal-reminder (e.g., mutilation) and core (e.g., rotten food) disgust domains. However, this overlap in brain activation was similar for all groups. A possible explanation for the lack of vaginismus-specific brain responses lies in the alleged female ambiguity (procreation/pleasure vs. contamination/disgust) toward penetration: generally in women a (default) disgust response tendency may prevail in the absence of sexual readiness. Accordingly, a critical next step would be to examine the processing of penetration stimuli following the induction of sexual arousal.

Giving in to arousal or staying stuck in disgust? Disgust-based mechanisms in sex and sexual dysfunction

Sex and disgust seem like strange bedfellows. The premise of this review is that disgust-based mechanisms nevertheless hold great promise for improving our understanding of sexual behavior, including dysfunctions. Disgust is a defensive emotion that protects the organism from contamination. Accordingly, disgust is focused on the border of the self, with the mouth and vagina being the body parts that show strongest disgust sensitivity. Given the central role of these organs in sexual behavior, together with the fact that bodily products are among the strongest disgust elicitors, the critical question seems not whether disgust may interfere with sex but rather how people succeed in having pleasurable sex at all. We argue that sexual arousal plays a critical role in counteracting disgust-induced avoidance via lowering the threshold for engaging in "disgusting sex." Following this, all mechanisms that interfere with the generation of sexual arousal or enhance the disgusting properties of sexual stimuli may hamper the functional transition from a sex-avoidance into an approach disposition. Since prolonged contact is the most powerful means to reduce disgust, disgust-based mechanisms that counteract sexual approach may give rise to a self-perpetuating cycle in which enhanced sexual disgust becomes a chronic feature.