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Concept: Sexual arousal

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Separate research streams have identified synchrony and arousal as two factors that might contribute to the effects of human rituals on social cohesion and cooperation. But no research has manipulated these variables in the field to investigate their causal - and potentially interactive - effects on prosocial behaviour. Across four experimental sessions involving large samples of strangers, we manipulated the synchronous and physiologically arousing affordances of a group marching task within a sports stadium. We observed participants' subsequent movement, grouping, and cooperation via a camera hidden in the stadium’s roof. Synchrony and arousal both showed main effects, predicting larger groups, tighter clustering, and more cooperative behaviour in a free-rider dilemma. Synchrony and arousal also interacted on measures of clustering and cooperation such that synchrony only encouraged closer clustering-and encouraged greater cooperation-when paired with physiological arousal. The research helps us understand why synchrony and arousal often co-occur in rituals around the world. It also represents the first use of real-time spatial tracking as a precise and naturalistic method of simulating collective rituals.

Concepts: Scientific method, Sociology, Sexual arousal, Sport, Stadium, Baseball park, Yankee Stadium, Citi Field

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The study purpose was to assess, in a U.S. probability sample of women, experiences related to orgasm, sexual pleasure, and genital touching. In June 2015, 1,055 women ages 18 to 94 from the nationally representative GfK KnowledgePanel® completed a confidential, Internet-based survey. More than one-third of American women (37%) reported they needed clitoral stimulation in order to experience orgasm during intercourse and 18% said that vaginal penetration was sufficient for orgasm. Women reported diverse preferences for genital touch location, pressure, shape, and pattern. Clinical, therapeutic, and educational implications are discussed.

Concepts: Sexual intercourse, Uterus, Concepts in metaphysics, Clitoris, Orgasm, Penis, Vulva, Sexual arousal

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Responsiveness may signal to a potential partner that one is concerned with her or his welfare, and may therefore increase sexual interest in this person. Research shows, however, that this proposition holds true for men, but not for women. In three studies, one observational and two experimental, we explored a potential mechanism that explains why men and women diverge in their sexual reactions to a responsive opposite-sex stranger. Studies 1 and 2 showed that men, but not women, perceived a responsive stranger as more gender typical (masculine/feminine) and, in turn, as more attractive. Study 3 revealed that responsiveness increased men’s perception of partner’s femininity. This, in turn, was associated with higher sexual arousal, which was, in turn, linked to greater partner attractiveness and greater desire for a long-term relationship. These findings suggest that whether responsiveness affects perceptions of partner attractiveness varies in individuals, depending on the contextually based meaning of responsiveness.

Concepts: Psychology, Gender, Cognition, Perception, Philosophy of perception, Sexual arousal, Physical attractiveness

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Precise spatiotemporal control of physiological processes by optogenetic devices inspired by synthetic biology may provide novel treatment opportunities for gene- and cell-based therapies. An erectile optogenetic stimulator (EROS), a synthetic designer guanylate cyclase producing a blue-light-inducible surge of the second messenger cyclic guanosine monophosphate (cGMP) in mammalian cells, enabled blue-light-dependent penile erection associated with occasional ejaculation after illumination of EROS-transfected corpus cavernosum in male rats. Photostimulated short-circuiting of complex psychological, neural, vascular, and endocrine factors to stimulate penile erection in the absence of sexual arousal may foster novel advances in the treatment of erectile dysfunction.

Concepts: Sexual intercourse, Andrology, Erectile dysfunction, Ejaculation, Penis, Cyclic guanosine monophosphate, Erection, Sexual arousal

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Gender differences in the specificity of sexual response have been a primary focus in sexual psychophysiology research, however, within-gender variability suggests sexual orientation moderates category-specific responding among women; only heterosexual women show gender-nonspecific genital responses to sexual stimuli depicting men and women. But heterosexually-identified or “straight” women are heterogeneous in their sexual attractions and include women who are exclusively androphilic (sexually attracted to men) and women who are predominantly androphilic with concurrent gynephilia (sexually attracted to women). It is therefore unclear if gender-nonspecific responding is found in both exclusively and predominantly androphilic women. The current studies investigated within-gender variability in the gender-specificity of women’s sexual response. Two samples of women reporting concurrent andro/gynephilia viewed (Study 1, n = 29) or listened (Study 2, n = 30) to erotic stimuli varying by gender of sexual partner depicted while their genital and subjective sexual responses were assessed. Data were combined with larger datasets of predominantly gyne- and androphilic women (total N = 78 for both studies). In both studies, women reporting any degree of gynephilia, including those who self-identified as heterosexual, showed significantly greater genital response to female stimuli, similar to predominantly gynephilic women; gender-nonspecific genital response was observed for exclusively androphilic women only. Subjective sexual arousal patterns were more variable with respect to sexual attractions, likely reflecting stimulus intensity effects. Heterosexually-identified women are therefore not a homogenous group with respect to sexual responses to gender cues. Implications for within-gender variation in women’s sexual orientation and sexual responses are discussed.

Concepts: Sexual intercourse, Gender, Gender role, Sexual orientation, Sexuality, Sexual arousal, Bisexuality, Sexual attraction

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Introduction: Synaesthesia is a phenomenon in which a certain stimulus induces a concurrent sensory perception; it has an estimated prevalence of 4%. Sexual arousal as an inducer for synaesthetic perceptions is rarely mentioned in the literature but can be found sometimes in case reports about subjective orgasmic experiences. Aims: To examine whether synaesthetic perceptions during sexual intercourse have an impact on the sexual experience and the extent of sexual trance compared to non-synaesthetes. Methods: In total, 19 synaesthetes with sexual forms of synaesthesia (17 female; 2 male) were included as well as corresponding control data of 36 non-synaesthetic subjects (n = 55). Two questionnaires were used to assess relevant aspects of sexual function and dysfunction (a German adaption of the Brief Index of Sexual Functioning, KFSP) as well as the occurrence and extent of sexual trance (German version of the Altered States of Consciousness Questionnaire, OAVAV). Additionally qualitative interviews were conducted in some subjects to further explore the nature of sexual experiences in synaesthetes. Main Outcome Measures: Sexual experience and extent of sexual trance during intercourse. Results: Synaesthetes depicted significantly better overall sexual function on the KFSP with increased scores for the subscale “sexual appetence” but coevally significant lower subscale scores for “sexual satisfaction.” Sexual dysfunction was not detected in this sample. Synaesthetes depicted significantly higher levels of the subscales “oceanic boundlessness” and “visionary restructuralization” than controls using the OAVAV. Qualitative interviews revealed varying synaesthetic perceptions during the different states of arousal. Furthermore, synaesthetes reported an unsatisfactory feeling of isolation caused by the idiosyncratic perceptions. Conclusions: Synaesthetes with sexual forms of synaesthesia seem to experience a deeper state of sexual trance without, however, enhanced satisfaction during sexual intercourse.

Concepts: Sexual intercourse, Orgasm, Qualia, Sexuality, Erection, Sexual arousal, Sexual function, Sexual dysfunction

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Studies of subjective and genital sexual arousal in monosexual (i.e. heterosexual and homosexual) men have repeatedly found that erotic stimuli depicting men’s preferred sex produce strong responses, whereas erotic stimuli depicting the other sex produce much weaker responses. Inconsistent results have previously been obtained in bisexual men, who have sometimes demonstrated distinctly bisexual responses, but other times demonstrated patterns more similar to those observed in monosexual men. We used fMRI to investigate neural correlates of responses to erotic pictures and videos in heterosexual, bisexual, and homosexual men, ages 25-50. Sixty participants were included in video analyses, and 62 were included in picture analyses. We focused on the ventral striatum (VS), due to its association with incentive motivation. Patterns were consistent with sexual orientation, with heterosexual and homosexual men showing female-favoring and male-favoring responses, respectively. Bisexual men tended to show less differentiation between male and female stimuli. Consistent patterns were observed in the whole brain, including the VS, and also in additional regions such as occipitotemporal, anterior cingulate, and orbitofrontal cortices. This study extends previous findings of gender-specific neural responses in monosexual men, and provides initial evidence for distinct brain activity patterns in bisexual men.

Concepts: LGBT, Sexual intercourse, Gender, Sexual orientation, Sexual arousal, Homosexuality, Bisexuality, Heterosexuality

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INTRODUCTION: Spontaneous orgasm triggered from inside the foot has so far not been reported in medical literature. AIMS: The study aims to report orgasmic feelings in the left foot of a woman. METHODS: A woman presented with complaints of undesired orgasmic sensations originating in her left foot. In-depth interview, physical examination, sensory testing, magnetic resonance imaging (MRI-scan), electromyography (EMG), transcutaneous electrical nerve stimulation (TENS), and blockade of the left S1 dorsal root ganglion were performed. MAIN OUTCOME MEASURES: The main outcomes are description of this clinical syndrome, results of TENS application, and S1 dorsal root ganglion blockade. RESULTS: Subtle attenuation of sensory amplitudes of the left suralis, and the left medial and lateral plantar nerve tracts was found at EMG. MRI-scan disclosed no foot abnormalities. TENS at the left metatarso-phalangeal joint-III of the left foot elicited an instant orgasmic sensation that radiated from plantar toward the vagina. TENS applied to the left side of the vagina elicited an orgasm that radiated to the left foot. Diagnostic blockade of the left S1 dorsal root ganglion with 0.8 mL bupivacaine 0.25 mg attenuated the frequency and intensity of orgasmic sensation in the left foot with 50% and 80%, respectively. Additional therapeutic blockade of the same ganglion with 0.8 mL bupivacaine 0.50 mg combined with pulsed radiofrequency treatment resulted in a complete disappearance of the foot-induced orgasmic sensations. CONCLUSION: Foot orgasm syndrome (FOS) is descibed in a woman. Blockade of the left S1 dorsal root ganglion alleviated FOS. It is hypothesized that FOS, occurring 1.5 years after an intensive care emergency, was caused by partial nerve regeneration (axonotmesis), after which afferent (C-fiber) information from a small reinnervated skin area of the left foot and afferent somatic and autonomous (visceral) information from the vagina on at least S1 spinal level is misinterpreted by the brain as being solely information originating from the vagina. Waldinger MD, de Lint GJ, van Gils APG, Masir F, Lakke E, van Coevorden RS, and Schweitzer DH. Foot orgasm syndrome: A case report in a woman. J Sex Med **;**:**-**.

Concepts: Nervous system, Uterus, Foot, Magnetic resonance imaging, Human sexuality, Orgasm, Sexual arousal, Lateral plantar nerve

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Despite 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.

Concepts: Gender, Knowledge, Sexual orientation, Transgender, Sexual arousal

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Introduction.  Research indicates that (i) women’s orgasm during penile-vaginal intercourse (PVI) is influenced by fitness-related male partner characteristics, (ii) penis size is important for many women, and (iii) preference for a longer penis is associated with greater vaginal orgasm consistency (triggered by PVI without concurrent clitoral masturbation). Aims.  To test the hypothesis that vaginal orgasm frequency is associated with women’s reporting that a longer than average penis is more likely to provoke their PVI orgasm. Method.  Three hundred twenty-three women reported in an online survey their past month frequency of various sexual behaviors (including PVI, vaginal orgasm, and clitoral orgasm), the effects of a longer than average penis on likelihood of orgasm from PVI, and the importance they attributed to PVI and to noncoital sex. Main Outcome Measures.  Univariate analyses of covariance with dependent variables being frequencies of various sexual behaviors and types of orgasm and with independent variable being women reporting vs. not reporting that a longer than average penis is important for their orgasm from PVI. Results.  Likelihood of orgasm with a longer penis was related to greater vaginal orgasm frequency but unrelated to frequencies of other sexual behaviors, including clitoral orgasm. In binary logistic regression, likelihood of orgasm with a longer penis was related to greater importance attributed to PVI and lesser importance attributed to noncoital sex. Conclusions.  Women who prefer deeper penile-vaginal stimulation are more likely to have vaginal orgasm, consistent with vaginal orgasm evolving as part of a female mate choice system favoring somewhat larger than average penises. Future research could extend the findings by overcoming limitations related to more precise measurement of penis length (to the pubis and pressed close to the pubic bone) and girth, and large representative samples. Future experimental research might assess to what extent different penis sizes influence women’s satisfaction and likelihood of vaginal orgasm. Costa RM, Miller GF, and Brody B. Women who prefer longer penises are more likely to have vaginal orgasms (but not clitoral orgasms): Implications for an evolutionary theory of vaginal orgasm. J Sex Med 2012;9:3079-3088.

Concepts: Sexual intercourse, Human sexuality, Vagina, Orgasm, Penis, Sexual arousal, Human penis size, Masturbation