CHFD 220 American Military University Exploration of Sexual Response and Arousal Discussion

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Sexual response cycle from The International Encyclopedia of Human Sexuality View article on Credo desire responsive desire sexual response cycle The sexual response cycle is a construction of William Masters and Virginia Johnson’s model based on data from a very large number of sexual responses, which they observed in their laboratory. The cycle is divided into four phases: the excitement phase, the plateau phase, the orgasm phase, and the resolution phase. The sexual response cycle, gender, and sexual desire are addressed in greater depth. The sexual response cycle is a construction of William Masters and Virginia Johnson based on data from a very large number of sexual responses, which they observed in their laboratory. The cycle is divided into four phases: the excitement phase, the plateau phase, the orgasm phase, and the resolution phase. These phases are arbitrarily defined, are not always clearly demarcated from one another, and may differ considerably, both in one person at different times and between different people. The diagrams of the cycle differ for men and women. In women, some differences have been observed in the plateau phase and in the orgasm phase; the orgasm may be a clear peak or multiple smaller peaks, without dropping below the plateau phase (Kolodny et al. 1979). In men’s diagrams a refractory period has been indicated to represent an unresponsive period after an ejaculation. It is important to note that several hundred volunteers, who were cooperative in producing their responses, provided data on sexual response in Masters and Johnson’s lab. However, sex therapists frequently reported that there often is a lack of cooperation between partners to resolve their sexual inadequacy. This, in addition to other arguments, has been an important reason for Helen Kaplan to propose a desire phase before the excitement phase (Kaplan 1974). Inadequacy of desire has been incorporated in DSM V (APA 2013) as hypoactive sexual desire disorder. The prevalence of desire problems in women is considerable. Basson (2006) reports desire problems in 10 to 51 percent of women surveyed in various countries. In men the processing of sexual information proceeds unconsciously up to a certain level, when men become aware of their arousal. Sexual information easily takes precedence over all other information men can attend to, and this seems to be a robust trait that only slowly becomes weaker, with aging. Becoming aware of sexual arousal after unconscious processing may be experienced as excitement and as desire occurring spontaneously. This also applies to excitement and desire in women, although attending to sexual over other information does not take precedence to the same extent, and consequently there is less experience of spontaneous excitement. When young, infatuated, and engaged in new relationships, women experience the same spontaneity as men do, but in relationships of longer duration information‐processing changes and the precedence of sexual information may wither away. This does not mean that these women cannot become sexually aroused; it only means that conditions for sexual arousal have changed. When they are allowed to be stimulated by their partner they may become excited, and consequently may desire to continue to increase their excitement. Basson (2001) coined this “responsive” desire to contrast it with the https://search.credoreference.com/content/entry/wileyhs/sexual_response_cycle/0 experience of spontaneous desire. SEE ALSO: Arousal, Sexual, Disorder; Desire, Sexual; Intercourse, Frequency; Intimacy; Masters and Johnson (the Work); Masters, William H. (1915–2001), and Virginia E. Johnson (1925–2013); Sex Therapy; Sexual Communication; Sexual Dysfunction; Socio‐sexual Response Cycle REFERENCES APA. 2013. Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (=DSM V). APA Washington, DC. Basson, Rosemary. 2001. “Using a Different Model for Female Sexual Response to Address Women’s Problematic Low Sexual Desire.” Journal of Sex and Marital Therapy, 27: 395-403. Basson, Rosemary. 2006. “Sexual Desire and Arousal Disorders in Women.” The New England Journal of Medicine, 354(14): 1497-1506. Kaplan, Helen S. 1974. The New Sex Therapy. Brunner/Mazel New York. Kolodny, Robert C.; William H. Masters; Virginia E. Johnson. 1979. Textbook of Sexual Medicine. Little, Brown Boston. FURTHER READING Georgiadis, Janniko R.; Morten L. Kringelbach; James G. Pfaus. 2012. “Sex for Fun: A Synthesis of Human and Animal Neurobiology.” Nature Reviews Urology, 9: 486-498. Walter Everaerd University of Amsterdam, The Netherlands Copyright © 2015 by John Wiley & Sons, Ltd. https://search.credoreference.com/content/entry/wileyhs/sexual_response_cycle/0 APA Everaerd, W. (2015). Sexual response cycle. In P. Whelehan, & A. Bolin (Eds.), The international encyclopedia of human sexuality. Hoboken, NJ: Wiley. Retrieved from https://search.credoreference.com/content/entry/wileyhs/sexual_response_cycle/0 Chicago Everaerd, Walter. “Sexual response cycle.” In The International Encyclopedia of Human Sexuality, edited by Patricia Whelehan, and Anne Bolin. Wiley, 2015. https://search.credoreference.com/content/entry/wileyhs/sexual_response_cycle/0 Harvard Everaerd, W. (2015). Sexual response cycle. In P. Whelehan & A. Bolin (Eds.), The international encyclopedia of human sexuality. [Online]. Hoboken: Wiley. Available from: https://search.credoreference.com/content/entry/wileyhs/sexual_response_cycle/0 [Accessed 25 September 2019]. MLA Everaerd, Walter. “Sexual response cycle.” The International Encyclopedia of Human Sexuality, edited by Patricia Whelehan, and Anne Bolin, Wiley, 1st edition, 2015. Credo Reference, https://search.credoreference.com/content/entry/wileyhs/sexual_response_cycle/0. Accessed 25 Sep. 2019. https://search.credoreference.com/content/entry/wileyhs/sexual_response_cycle/0 Neurology and sex from The International Encyclopedia of Human Sexuality View article on Credo genital nerves orgasm brain injury spinal cord injury disease surgery This article reviews selected aspects of the role of the nervous system in human sexual response. We address the division of labor of the nerves conveying sensory information from specific genital regions in women and men to activate the brain, and how the brain then generates the response of the genital components to sexual arousal and orgasm. Then we address neural pathologies (diabetes, spinal cord and brain injury, autonomic dysreflexia, epilepsy, parkinsonism, multiple sclerosis) that affect sexual response, and finally we address interventions (brain surgery, hysterectomy, prostatectomy) that affect sexual response. Questions raised by recent findings are presented as grist for further research. From genitals to brain W o me n In women, each genital region is supplied by different sensory nerves, primarily the hypogastric, pelvic, and pudendal nerves. Sensory activity is provided from the uterus and cervix by the hypogastric nerves, from the cervix and vagina by the pelvic nerves, and from the clitoris by the pudendal nerves. A fourth pair of nerves—the vagus nerves—(cranial nerve 10) conveys sensory activity from the cervix directly to the brain, bypassing the spinal cord (Komisaruk, Beyer‐Flores, and Whipple 2006). The clitoris, vagina, and cervix project sensory activity separately to distinct, but overlapping, localized regions of the sensory cortex (the medial paracentral lobule). Curiously, nipple stimulation activates this same genital sensory cortical region (Komisaruk et al. 2011). Contrary to claims in the literature, vaginal sensation is not a consequence of indirect stimulation of the clitoris, for the vagina has its own sensory innervation, separate from that of the clitoris. Women’s reports that orgasms from clitoral, vaginal, or cervical stimulation feel distinctly different from each other are consistent with the differences in the corresponding sensory nerves and their projection pathways. Analysis of the relative sensitivity of selected genital and other regions showed the sequence (from least to most sensitive) labia minora < clitoris < labia majora < abdominal skin < back of hand. The clitoris has been described as having the densest sensory innervation of the human body. Within the vagina, the greatest sensitivity was found to be anterior and the least was posterior. The anterior region, close to the pubic bone, has been termed the G spot, stimulation of which is described by some women as highly erotogenic. While there is no reliable evidence of a unique corresponding anatomical structure, pressure exerted in that uniquely situated region could also indirectly stimulate the “legs” of the wishbone‐shaped clitoris (which straddle that region of the vagina), the urethra, the urinary bladder, and a rich nerve plexus, the combination of which could produce unique erotic quality (Jannini et al. 2012). A question for future research is the difference in brain regional activation when genital stimulation is perceived as feeling prosaic (e.g., when https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 sitting down) in contrast to when it is perceived as feeling erotic. At orgasm induced by genital self‐stimulation, there is an increase in most brain systems, including hypothalamus (which secretes oxytocin), limbic systems components (e.g., amygdala, hippocampus), nucleus accumbens (considered a “reward” area), insula and anterior cingulate cortex (regions intriguingly activated also by pain), and frontal cortex (“executive” brain function) (Komisaruk, Beyer‐Flores, and Whipple 2006). Other studies have reported that, in response to partner stimulation, the frontal cortex decreases in activity during orgasm. This difference may be related to brain scan methodology— respectively, fMRI or PET. The similarities in brain activity in women’s versus men’s orgasms appear to be greater than the differences. Me n In men, the pudendal nerves convey sensory activity from the penile skin and scrotum, and the hypogastric nerves convey sensory activity from the testicles and the prostate gland. In the spinal cord, testicular pain sense is conveyed to the brain via the spinothalamic tract, which originates in the spinal cord and projects via the thalamus to the paracentral lobule of the cerebral cortex, the same region as in women (Kell et al. 2005). If this tract and closely adjacent regions are cut surgically, then not only is the pain abolished, but also psychogenic erection and orgasm in men and women, although not sexual desire. This further indicates an intriguing connection between the neural systems mediating orgasm and pain (Komisaruk, Beyer‐Flores, and Whipple 2006). The cascade of neural events that trigger ejaculation are still unresolved, i.e., whether reflexively by sensory activity generated by increased pressure of semen in the duct system, and/or critical level of excitation in brain and/or spinal cord (Levin 2005). From brain to genitals W o me n Clitoral and labial engorgement during sexual arousal are produced by pelvic (parasympathetic) nerve efferent activity. The hypogastric (sympathetic) nerves generate vaginal lubrication, which is not a glandular secretion, but rather a “transudate”; that is, a filtrate through the walls of blood vessels that supply the vagina. Contractions of the pubo‐coccygeal muscles of the pelvic floor that surround the vaginal opening, and urethral and anal sphincters, are controlled by pudendal nerve efferents (Levin 2002). Uterine contractions increase in response to sexual arousal. They are produced primarily by blood‐borne oxytocin, which is synthesized in a small group of hypothalamic neurons, transported and stored in the posterior pituitary gland, and released into the bloodstream in response to sexual arousal and orgasm. In response to cervical stimulation produced by the fetus’s head pressing against the cervix, oxytocin is released into the bloodstream, stimulating uterine contractions during childbirth (the Ferguson reflex), thus hastening delivery. Suckling stimulation also releases pituitary oxytocin into the bloodstream; the oxytocin stimulates the contraction of specialized “myo‐epithelial” cells that surround the mammary glands like fingers, thereby forcibly ejecting milk into the baby’s mouth (the “milk‐ejection reflex”). The activation of this brain‐ mediated oxytocin system both by sexual stimulation and by childbirth may account for some women’s claims that childbirth feels orgasmic (Komisaruk, Beyer‐Flores, and Whipple 2006). The neural mediation of female ejaculation is unknown. Me n Penile erection is primarily controlled by pelvic nerve (parasympathetic) efferent activity. Seminal emission https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 and ejaculation, involving prostate, seminal vesicles, and vas deferens, are primarily controlled by hypogastric nerve (sympathetic) efferent activity. Pudendal nerve efferents control the striated muscles that comprise the external urethral and anal sphincters and the pelvic floor (bulbo‐ and ischio‐cavernosus) muscles, thereby helping to intensify penile erection, facilitate ejaculation by producing rhythmical contractions of these muscles during orgasm, and prevent incontinence during sexual activity (Levin 2005). In response to sexual arousal, pelvic nerve efferent activity releases nitric oxide into the smooth muscles of the blood vessels and sinuses in the corpora cavernosa of the penis, increasing levels of cyclic guanosine monophosphate (cGMP) locally, which relaxes the muscles, thereby allowing an increase in arterial blood flow into the sinuses. The increasing volume squeezes closed the veins draining the penis by compressing them against the flexible, but nonstretchable (like aluminum foil) tunica albuginea, which encapsulates the penile shaft. This process results in penile erection. After ejaculation, the trabecular muscles contract, allowing the venous channels to dilate and the trapped blood to exit the penis, resulting in loss of erection. Erection‐enhancing pharmaceuticals block the enzyme phosphodiesterase‐5, which normally breaks down the cGMP, thus augmenting the action of cGMP on relaxing the penile smooth muscles, and thereby intensifying erection (Lue 2000). Two aspects of the ejaculatory process are still not resolved: exactly how the rhythmical spurts of semen are produced, and whether the pleasurable sensation of orgasm is a consequence of the sensory activity produced by the ejaculation mechanics or primarily a brain phenomenon. Pathology Ne rve d a ma g e : d ia b e t e s Diabetes increases the incidence of sexual problems in men (erectile dysfunction, retrograde ejaculation, neurogenic bladder) and women (decrease in vaginal lubrication and vulvar sensitivity), evidently resulting from a combination of sensory and autonomic neurological pathologies which, in combination with vascular damage, reduces the blood flow to genital tissues, compromising their function. S p ina l co rd injury: w o me n The effects of spinal cord injury (SCI) on sexual response vary according to the location and “completeness” of the injury and the specific genital response, because the afferent and efferent genital nerves connect to the spinal cord at different cord levels. The pudendal nerves, which convey clitoral sensation, enter the spinal cord at sacral levels 2–4, so “complete” SCI (cSCI) at that level or above blocks clitoral sensibility. The hypogastric nerves, which convey cervical and uterine sensation, enter the cord at thoracic levels 10–12, bypassing the lumbar and sacral levels. Consequently, pregnant women who have cCSI below thoracic level 12 can feel their uterus contracting and their fetus moving, because the hypogastric nerve afferents enter above the level of the injury and retain access to the brain. Because the hypogastric nerve efferents regulate blood flow and thereby control vaginal lubrication, women with cSCI below thoracic 12 can experience psychogenic vaginal lubrication, but women with cSCI above thoracic 10 cannot. However, women with cSCI above thoracic 10 have intact pudendal nerve afferents and hypogastric nerve efferents, so they can experience reflexive, but not psychogenic, vaginal lubrication (Komisaruk, Gerdes, and Whipple 1997). Within the spinal cord, genital afferent activity is conveyed to the brain via the spinothalamic tract. Interruption of this pathway blocks clitoral stimulation‐induced orgasm. However, it is intriguing that women with cSCI above thoracic 10, and even higher, can have cervical and vaginal sensibility and can experience https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 orgasms from that stimulation. The afferent pathway is evidently via the vagus nerves. Functional magnetic resonance imaging brain scanning provides evidence that the brain region to which the vagus nerves project is activated by cervical or vaginal stimulation in women with cSCI above thoracic 10. Thus, there are evidently two separate genital‐orgasmic neural pathways in women: the main pathway within and the “auxiliary” pathway bypassing the spinal cord (Komisaruk et al. 2004). S p ina l co rd injury: me n In men as in women, genital afferent activity is conveyed to the brain within the spinal cord via the spinothalamic tract. Surgical interruption of this tract, used as a desperate measure to block intractable abdominal or pelvic cancer pain, abolished orgasm as a side effect. Curiously, months later, when the pain recurred, so did orgasmic ability. In the case of SCI, the location and completeness of SCI affects psychogenic and reflex erection and ejaculation differentially. Thus, if the sacral (i.e., terminal) level of the spinal cord is damaged (i.e., the “conus medullaris”), both the sensory input from the penis and the descending psychogenic activity are denied access to the pelvic nerve output, so reflexive and psychogenic erection (and thereby subsequent ejaculation) are blocked. If the cSCI is above the sacral level but below the exit zone of the hypogastric nerve roots, then reflex erection can occur, but penile afferent access to the hypogastric outflow is blocked, so ejaculation cannot occur. If the cSCI is above the level of the hypogastric nerve outflow, then reflex erection and ejaculation can both occur, but psychogenic descending access to both outflows is blocked, so psychogenic erection cannot occur (Komisaruk, Beyer‐Flores, and Whipple 2006). Men with cSCI and no genital sensation have reported “phantom” orgasms in their dreams, indicating the critical role of the brain in orgasm, independent of the genitals. Whether the vagus nerves have a genital sensory role in men is an open question. A man and a woman with an amputated foot reported that in response to genital stimulation (which, in the sensory cortex, is represented adjacent to the foot) they felt orgasms extending into their phantom foot (Ramachandran and Blakeslee 1999). A ut o no mic d ys re fle xia Autonomic dysreflexia is a neurological syndrome in persons with cSCI at thoracic 6 or above. Visceral or somatic sensory stimulation originating below the level of injury—for example, genital stimulation, sexual intercourse, childbirth, or full rectum or bladder—generates an increase in blood pressure. The normal descending inhibitory pathways from the brain are blocked by the cSCI, thereby allowing the blood pressure to increase precipitously, potentially leading to a fatal stroke. B ra in injury Traumatic brain injury can produce variable effects on sexual behavior, including decreased or increased libido, loss of genital sensation, reduced lubrication, erectile and ejaculatory dysfunction, anorgasmia, and socially and sexually uninhibited, inappropriate behavior, including unwelcome advances and exhibitionism, contrasting with the individual’s pretrauma behavior (Baird et al. 2007). These cases of sexual disinhibition have been attributed predominantly to damage to frontal or temporal cortical regions. A generalization to account for the aberrant behavior is that learning of social graces, especially the acculturation of intricate social inhibitions, is among the most subtle and longest in latency to develop brain processes, which normally involve these cortical regions. Consequently, damage to those brain regions eliminates the subtlety (as opposed to more “primitive” functions—e.g., breathing, eating, locomotion), resulting in behavioral disinhibition, manifested most evidently in socially inappropriate, especially sexual, behavior. https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 E p ile p s y Many men and women describe orgasmic feelings (“orgasmic aura”) just prior to the onset of an epileptic seizure, originating most commonly from the right temporal lobe of the forebrain, which contains the hippocampus and amygdala. The aura may have a spontaneous onset or may be triggered by some specific stimulus (e.g., brushing the teeth). The seizure‐related orgasms may be described as “unwelcome,” but in other cases pleasurable. One woman reportedly refused antiepileptic medication because she enjoyed her orgasmic auras and did not want to have them eliminated. When seizures develop in the genital sensory cortex, the orgasms are reported to feel as if generated by genital stimulation. However, seizures that develop elsewhere in the brain are not necessarily experienced as involving genital sensation and have been described as generating “nongenital orgasms” (Komisaruk, Beyer‐Flores, and Whipple 2006). P a rk ins o nis m Significant deleterious effects on sexuality and orgasm have been reported in men and women with parkinsonism, including erectile dysfunction, anorgasmia, decreased sexual interest and drive, and sexual frequency. On the basis of the extensive evidence of the role of dopamine in sexual response and orgasm (see Komisaruk, Beyer‐Flores, and Whipple 2006), it is likely that the loss in sexual response and orgasm in parkinsonism—as well as the loss of motor function—is closely related to the deterioration of the dopaminergic neuronal system, which is diagnostic of this disease (Rees, Fowler, and Maas 2007). Mult ip le s cle ro s is Multiple sclerosis in men is associated with reduced desire; erectile, orgasmic, and ejaculatory dysfunction; fatigue; depression; spasticity; and incontinence anxiety. In women, commonly reported are genital sensory dysfunction, loss of libido, decreased vaginal lubrication, increased spasticity during sexual activity, and loss of orgasmic capacity (Rees, Fowler, and Maas 2007). Surgery B ra in s urg e ry Before the advent of psychotropic pharmaceuticals, hundreds of human brain‐lesioning procedures (“psychosurgery”) were carried out. Some, but not all, noted increased sexuality following frontal lobotomy, in which cases reduced tendency to seek sexual gratification was accompanied by disinhibited sexual expression. This led to the following advice by the surgeons, Freeman and Watts, who performed the most lobotomies: “Her husband may have regressed to the cave‐man level, and she owes it to him to be responsive at the cave‐woman level. It may not be agreeable at first, but she will soon find it exhilarating if unconventional.” The “hypersexuality” reported after surgical removal of portions of the temporal lobe containing hippocampus and amygdala may be a combination of loss of discrimination of appropriate sexual objects, loss of social inhibitions, and increased sexual desire. This has been termed the Klüver–Bucy syndrome, after the investigators who initially performed this surgery in rhesus and observed behavioral alterations, including copulation attempts with other species and inanimate objects. Changes in social behavior, departing from the patients’ behavior prior to the surgery were reported, including exhibitionism, hetero‐ and homosexual advances to strangers, public masturbation, and intergenerational sex. Similar changes in behavior were observed after surgical damage to the septal region, basal forebrain, and upper or lower brainstem regions. In the 1970s in Germany, attempts were made to control intergenerational sex and “sexual delinquency” through the use of unilateral surgical removal of the ventromedial or medial anterior https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 hypothalamus (Komisaruk, Beyer‐Flores, and Whipple 2006). H ys t e re ct o my Most hysterectomies for benign conditions are performed to alleviate pain and/or vaginal or uterine bleeding, which generally improve the patients’ sexual life. However, many patients report resulting vaginal dryness and loss of sexual interest and libido. In a recent review of the hysterectomy literature it was pointed out that while almost every outcome report stated overall benefits, nevertheless some women in almost all of the same reports found reduced vaginal sensation. The discrepancies may be due to the women’s individual preferences for source of stimulation (e.g., clitoral versus vaginal), a factor that is typically not reported and that could be affected differentially depending on which nerves are cut in the surgery. There are only scant reports in the literature of the use of nerve‐sparing hysterectomy procedure (Komisaruk, Frangos, and Whipple 2011). P ro s t a t e ct o my By contrast, the use of nerve‐sparing prostatectomy procedures is commonly reported. Nerve‐sparing radical prostatectomy removes the seminal vesicles and prostate, cutting the branches of the neurovascular bundle that enter the prostate, while leaving intact the part of the bundle that continues into the penis. Orgasmic response can be preserved despite the prevalent sequela of erectile dysfunction, the latter of which can be aided prosthetically (Lue 2000). SEE ALSO: Anatomy, Female; Anatomy, Male; Erection; Erogenous Zones; G Spot; Gynecologic Surgery; Lactation; Orgasm; Sexual Dysfunction; Vaginal Lubrication REFERENCES Baird, Amee D.; Sarah J. Wilson; Peter F. Bladin; Michael M. Saling; David C. Reutens. 2007. “Neurological Control of Human Sexual Behavior: Insights from Lesion Studies.” Journal of Neurology, Neurosurgery & Psychiatry, 78: 1042-1049. Jannini, Emmanuele A.; Alberto Rubio‐Casillas; Beverly Whipple; Odile Buisson; Barry R. Komisaruk; Stuart Brody. 2012. “Female Orgasm(s): One, Two, Several.” Journal of Sexual Medicine, 9: 956-965. Kell, Christian A.; Katharina von Kriegstein; Alexander Rosller; Andreas Kleinschmidt; Helmut Laufs. 2005. “The Sensory Cortical Representation of the Human Penis: Revisiting Somatotopy in the Male Homunculus.” Journal of Neuroscience, 25: 5984-5987. Komisaruk, Barry R.; Carolyn Gerdes; Beverly Whipple. 1997. “‘Complete’” Spinal Cord Injury Does Not Block Perceptual Responses to Genital Self‐Stimulation in Women.” Archives of Neurology, 54: 1513-1520. Komisaruk, Barry R.; Beverly Whipple; Audrita Crawford; Sherry Grimes; Wen‐Ching Liu; Andrew Kalnin; Kristine Mosier. 2004. “Brain Activation during Vaginocervical Self‐Stimulation and Orgasm in Women with Complete Spinal Cord Injury: fMRI Evidence of Mediation by the Vagus Nerves.” Brain Research, 1024: 7788. Komisaruk, Barry R.; Carlos Beyer‐Flores; Beverly Whipple. 2006. The Science of Orgasm. The Johns Hopkins University Press Baltimore. Komisaruk, Barry R.; Eleni Frangos; Beverly Whipple. 2011. “Hysterectomy Improves Sexual Response? Addressing a Crucial Omission in the Literature.” Journal of Minimally Invasive Gynecology, 18: 288-295. Komisaruk, Barry R.; Nan Wise; Eleni Frangos; Wen‐Ching Liu; Beverly Whipple; Stuart Brody. 2011. “Women’s Clitoris, Vagina and Cervix Mapped on the Sensory Cortex, Using fMRI.” Journal of Sexual https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 Medicine, 8: 2822-2830. Levin, Roy J. 2002. “The Physiology of Sexual Arousal in the Human Female: A Recreational and Procreational Synthesis.” Archives of Sexual Behavior, 31: 405-411. Levin, Roy J. 2005. “The Mechanisms of Human Ejaculation—A Critical Analysis.” Sexual and Relationship Therapy, 20: 123-131. Lue, Tom F. 2000. “Erectile Dysfunction.” New England Journal of Medicine, 342: 1802-1813. Ramachandran, Vilayanur S.; Sandra Blakeslee. 1999. Phantoms in the Brain: Human Nature and the Architecture of the Mind. Fourth Estate London. Rees, Peter M.; Clare J. Fowler; Cornelis P. Maas. 2007. “Sexual Function in Men and Women with Neurological Disorders.” Lancet, 369: 512-525. FURTHER READINGS Hyde, Janet Shibley; John D. DeLamater. 2010. Understanding Human Sexuality, 11th ed. McGraw‐Hill New York. Komisaruk, Barry R.; Beverly Whipple; Sara Nasserzadeh; Carlos Beyer‐Flores. 2010. The Orgasm Answer Guide. The John Hopkins University Press Baltimore. Leiblum, Sandra. 2007. Principles and Practice of Sex Therapy, 4th ed. Guilford Press New York. Netter, Frank H. 2006. Atlas of Human Anatomy, 4th ed. Saunders Elsevier Philadelphia. Barry R. Komisaruk Rutgers University, United States Maria Cruz Rodriguez del Cerro Universidad Nacional de Educacion a Distancia, Spain Copyright © 2015 by John Wiley & Sons, Ltd. https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 APA Komisaruk, B. R., & del Cerro, M. C. R. (2015). Neurology and sex. In P. Whelehan, & A. Bolin (Eds.), The international encyclopedia of human sexuality. Hoboken, NJ: Wiley. Retrieved from https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 Chicago Komisaruk, Barry R., and Maria Cruz Rodriguez del Cerro. “Neurology and sex.” In The International Encyclopedia of Human Sexuality, edited by Patricia Whelehan, and Anne Bolin. Wiley, 2015. https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 Harvard Komisaruk, B.R. and del Cerro, M.C.R. (2015). Neurology and sex. In P. Whelehan & A. Bolin (Eds.), The international encyclopedia of human sexuality. [Online]. Hoboken: Wiley. Available from: https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 [Accessed 25 September 2019]. MLA Komisaruk, Barry R., and Maria Cruz Rodriguez del Cerro. “Neurology and sex.” The International Encyclopedia of Human Sexuality, edited by Patricia Whelehan, and Anne Bolin, Wiley, 1st edition, 2015. Credo Reference, https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0. Accessed 25 Sep. 2019. https://search.credoreference.com/content/entry/wileyhs/neurology_and_sex/0 Arousal, sexual from The International Encyclopedia of Human Sexuality View article on Credo dual control model New View Campaign sexual arousal sexual desire sexual problems Sexual arousal is a complex interconnection between emotional and physical components, which often overlaps with sexual desire and appears to be influenced by age and hormonal status. Most of the research on sexual arousal focuses on two aspects of sexual arousal: genital and subjective. Genital arousal refers to the specific physiological changes that occur. Subjective, or self‐reported, sexual arousal refers to the emotional state of arousal. Sexual arousal is not stable and may be influenced by a number of ongoing factors. The dynamic nature of sexual arousal is not well understood and treatment related to sexual arousal difficulties is likely to remain controversial for some time. Sexual arousal is often considered to have both emotional and physical components. As an emotional state, it may be initiated or enhanced by processing internal (e.g., fantasy, hormonal) or external (e.g., tactile, visual) sexual stimuli. Physiological components to sexual arousal are commonly equated with genital response, with vaginal lubrication and enhanced blood flow to the genitals among the arousal indicators for women, and penile erection among the arousal indicators for men. However, physical signs of sexual arousal are not limited to the genitals and may include increases in heart rate, breathing, and sex flush (a pink area, due to increased blood flow, of the chest). Arousal is also sometimes described in psychological terms as a state motivated toward the experience of sexual pleasure which involves cognitive information to accompany the genital response. Sexual arousal varies among individuals and within individuals across time. There are interacting components to sexual arousal; these include physiological changes, emotional expression, and motivated behavior resulting from the physiological and emotional components. Considerable complexity surrounds sexual arousal due to the number of discordances that can occur between different components in addition to potential confusion with other aspects of sexual response, such as sexual desire. Sometimes the physical state of being sexually aroused is an indication to a person that sexual desire is present. For others, feeling sexual desire is an indication to them that they are sexually aroused. Conflated perceptions of sexual arousal and desire have been noted as particularly common among women. Most of the research on sexual arousal focuses on two aspects of sexual arousal: the genital and the subjective (self‐reported). Genital arousal refers to the specific physiological changes that occur. Self‐ reported, or subjective, sexual arousal refers to the emotional state of sexual arousal. Some researchers also collect information on self‐reported genital response as a subjective estimate of the extent of physiological response. Early scientific research related to physical aspects of sexual arousal was conducted by Alfred Kinsey and colleagues (1948, 1953). In addition to assessing sexual arousal and interest through interview data, the https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 research team assessed physically observable changes related to sexual arousal such as heart rate changes during sexual activity. During the 1950s and 1960s, Masters and Johnson (1966) used direct observation methods of masturbation and intercourse to record some of the first data on the anatomy and physiology of sexual response. For both men and women, genital sexual arousal (e.g., penile erection, vaginal lubrication, darkening labia) largely reflects genital vasocongestion. Although many of the changes they noted have been replicated in later studies, other changes that they noted, such as changes in size of the breasts and testicles, have been less well established, particularly in instances in which the details of how they originally conducted their measurements were not published. Currently, there are some psychometrically valid measurement tools available for assessing genital vasocongestion. These include vaginal photoplethysmograph, a circumferential penile plethysmograph, and genital thermography. The vaginal photoplethysmograph measures increases in vasocongestion of the vaginal epithelium. The penile plethysmograph measures changes in penile circumference as vasocongestion causes erection. Measuring erection with the penile plethysmograph assesses the end‐ state of genital vasocongestion in men. Although the vaginal photoplethysmograph is a direct measure of vaginal lubrication, the relationship between vasocongestion and vaginal lubrication is poorly understood. Thermography is a noninvasive technique that allows for measurement of heat generation patterns, which can be used to assess blood flow into the clitoris, labia, and other parts of the genitals. Clitoral ultrasonography has also been assessed as a measure of physical aspects of sexual arousal; however, there is less support for this method. Psychophysiology is often used to examine sexual arousal because it places emphasis on the interplay between subjective (affective and cognitive) and physiological determinants. A large body of psychophysiological research is dedicated to the study of and discordance between genital and self‐ reported arousal. In particular, research has shown variable patterns based on gender and sexual orientation. In women, the discordant pattern most frequently found is that genital response is detected while subjective sexual arousal is low or absent. Generally, higher correlations between genital and subjective sexual arousal is found in men. However, discordant patterns can also be found in men. Some research has found that different experimental manipulations or researching men with erectile problems result in discordant patterns. There is also a large body of research on sexual orientation and sexual arousal. In men, we typically see a category‐specific pattern of sexual arousal, indicating that their patterns of genital and subjective sexual arousal correspond to their stated or observed sexual interests when presented with sexual stimuli. This has been shown to be true for men who are sexually attracted to same‐ and opposite‐sex partners. It is also true for men who are attracted to physically immature persons (i.e., pedophiles) or to fetishistic objects (e.g., transvestic fetishism). In women, the relationship between sexual interests and sexual arousal is less straightforward than in men. Women’s subjective sexual arousal can be described as category‐specific, but their genital sexual arousal is best described as non‐specific. Women have consistently demonstrated increases in genital response to both preferred and non‐ preferred sexual stimuli, with no greater response to preferred stimuli. Janssen and Bancroft (2006) were the first to introduce The Dual Control Model, a state‐trait model used to explain sexual arousal. This model postulates that sexual arousal and associated behaviors depend on the balance between sexual excitation and sexual inhibition. The weighing of excitatory and inhibitory processes determines whether or not a sexual response will occur in a given individual in a given situation. The model assumes individual variability in the propensity for these two processes and it acknowledges both psychological processes and genital response. The connection between the psychological and genital https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 relies on the presence of a sexual stimulus and the absence of a process that interferes with that stimulus. According to this model, the balance of excitation and inhibition is what determines whether one will experience sexual arousal in a given situation. Normative changes to sexual arousal Sexual arousal, like many areas of sexual response and behavior, appears to be influenced by age and hormonal status. For example, significantly more women experience difficulties with vaginal lubrication and more men experience erectile difficulties with older age. Women may also experience lower sexual arousal during the advanced stages of pregnancy, during the postpartum period, and in connection with menopause. There is also support for the fluid nature of sexual arousal, with research documenting the ebbs and flows of desire (again, often conflated with arousal) or “lust” in long‐term relationships and marriages. That is, sexual arousal and desire are not stable and may be influenced by a number of factors on an ongoing basis. The dynamic nature of sexual arousal is not well understood. Sexual arousal difficulties: Do we leave this as the DSM‐IV or attempt to fix it? The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM‐IV) (2000) lists two sexual arousal disorders: Female Sexual Arousal Disorder and Male Erectile Disorder. The former is classified in terms of an inadequate lubrication swelling response and the latter is classified in terms of an inability to attain or maintain an adequate erection for the duration of sexual activity. An additional sexual arousal problem has been proposed for women: Persistent Genital Arousal Disorder. This involves genital and breast vasocongestion and sensitivity that persists for hours or days, is not associated with any cognitive, emotional, or subjective arousal, and is difficult to relieve, even with orgasm (Leiblum and Nathan 2001). Subsequently, in DSM‐5 (2013), changes were made in these classifications (Waguih and Tobia 2013). Female Sexual Arousal Disorder was renamed Female Sexual Interest/Arousal Disorder and a new category for men, in addition to Erectile Disorder (male was dropped), was added: Male Hypoactive Sexual Desire Disorder. The Female Sexual Interest/Arousal Disorder “added four new criteria taking into account absent or decreased activity in four additional aspects of sex life: initiation of sexual activity or responsiveness to a partner’s attempts to initiate it, excitement and pleasure, response to sexual cues, and sensations during sexual activity, whether genital or non‐genital … The requirements for male hypoactive desire disorder are exactly the same as those for undifferentiated hypoactive desire disorder in the DSM‐IV” (Waguih and Tobia 2013). The criteria include: “Deficient or absent sexual fantasies and desire for sexual activity. This judgment must be made by a clinician taking into account the individual’s age and life circumstances. The lack of desire must result in significant distress for the individual and is not better accounted for by another disorder or physical diagnosis” (American Psychiatric Association, DSM‐IV‐TR 2000; http://allpsych.com/disorders/sexual/hypoactivesexual.html). In recent years, a number of research studies have considered the prevalence of sexual arousal difficulties among adult men and women, and have assessed products that enhance sexual arousal. Some research has found that vibrator use is related to higher scores on measures of self‐reported sexual arousal. Other research has examined the use of creams (sometimes called “arousal creams”) and their efficacy in terms of enhancing sexual desire and arousal, with equivocal results. The New View Campaign is a grassroots group formed in 2000 by Dr. Leonore Tiefer (2001) with the purpose of challenging messages and https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 research related to what members perceived as the “medicalization” of women’s sexuality (i.e., a sense that women’s sexual problems were largely biological in nature and could be easily fixed with medication). The New View Campaign encourages a larger worldview of sexuality, including sexual arousal, and asks that researchers and clinicians consider the range of factors—biological, social, relational, societal—that may affect a woman’s sexuality. Aspects of sexuality research and treatment related to sexual arousal are likely to remain controversial for some time. SEE ALSO: Desire, Sexual; Psychosexual Functioning and Adjustment; Sex Research; Sex Therapy; Sex Toys and Aids; Sexual Dysfunction; Sexual Identity and Sexual Orientation; Sexual Response Cycle REFERENCES American Psychiatric Association. 2000. Diagnostic and Statistical Manual of Mental Disorders: (DSM‐IV‐ TR). http://allpsych.com/disorders/sexual/hypoactivesexual.html. American Psychiatric Association. 2013. Diagnostic and Statistical Manual of Mental Disorders: (DSM‐5), 5th ed. APA Washington, DC. Chivers, M. L.; J. M. Bailey. 2005. “A Sex Difference in Features that Elicit Genital Response.” Biological Psychology, 70: 115-120. Janssen, E.; J. Bancroft. 2006. “The Dual Control Model: The Role of Sexual Inhibition and Excitation in Sexual Arousal and Behavior.” In The Psychophysiology of Sex, edited by E. Janssen. Indiana University Press Bloomington IN. Kinsey, Alfred C.; Wardell B. Pomeroy; Clyde E. Martin. 1948. Sexual Behavior in the Human Male. W. B. Saunders Philadelphia PA. Kinsey, Alfred C.; Wardell B. Pomeroy; Paul Gebhard; Clyde E. Martin. 1953. Sexual Behavior in the Human Female. W. B. Saunders Philadelphia PA. Leiblum, Sandra; Sharon G. Nathan. 2001. “Persistent Sexual Arousal Syndrome: A Newly Discovered Pattern of Female Sexuality.” Journal of Sex & Marital Therapy, 27(4): 365-380. Masters, William; Virginia Johnson 1966. Human Sexual Response. Little, Brown Boston MA. Tiefer, Leonore. 2001. “A New View of Women’s Sexual Problems: Why New? Why Now?” The Journal of Sex Research, 38(2): 89-96. Waguih, William IsHak; Gabriel Tobia. 2013. “Changes in Diagnostic Criteria of Sexual Dysfunctions. Reproductive System & Sexual Disorders.” Accessed June 2013. http://omicsonline.org/dsm‐5‐changes‐in‐ diagnostic‐criteria‐of‐sexual‐dysfunctions‐2161‐038X.1000122.php?aid=18508. FURTHER READINGS Chivers, M. L.; E. G. Rieger; E. Latty; J. M. Bailey. 2004. “A Sex Difference in the Specificity of Sexual Arousal.” Psychological Science, 15: 736-744. Janssen, E. 2002. “Psychophysiological Measures of Sexual Response.” In Handbook for Conducting Research on Human Sexuality, edited by M. W. Wiederman and B. E. Whitley, 139-171. Lawrence Erlbaum Mahwah NJ. Rosen, R. C.; J. G. Beck. 1988. Patterns of Sexual Arousal: Psychophysiological Processes and Clinical Applications. Guilford Press New York. Kristen Mark https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 University of Kentucky, Lexington, United States Debby Herbenick Indiana University, Bloomington, United States Copyright © 2015 by John Wiley & Sons, Ltd. https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 APA Mark, K., & Herbenick, D. (2015). Arousal, sexual. In P. Whelehan, & A. Bolin (Eds.), The international encyclopedia of human sexuality. Hoboken, NJ: Wiley. Retrieved from https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 Chicago Mark, Kristen, and Debby Herbenick. “Arousal, sexual.” In The International Encyclopedia of Human Sexuality, edited by Patricia Whelehan, and Anne Bolin. Wiley, 2015. https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 Harvard Mark, K. and Herbenick, D. (2015). Arousal, sexual. In P. Whelehan & A. Bolin (Eds.), The international encyclopedia of human sexuality. [Online]. Hoboken: Wiley. Available from: https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 [Accessed 25 September 2019]. MLA Mark, Kristen, and Debby Herbenick. “Arousal, sexual.” The International Encyclopedia of Human Sexuality, edited by Patricia Whelehan, and Anne Bolin, Wiley, 1st edition, 2015. Credo Reference, https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0. Accessed 25 Sep. 2019. https://search.credoreference.com/content/entry/wileyhs/arousal_sexual/0 Sexual and Relationship Therapy Vol. 25, No. 4, November 2010, 415–428 Reprinted from Sexual and Marital Therapy, Vol. 20, No. 4, 2005, 377–390 ISSN 1468-1994 print/ISSN 1468-1749 online Ó [2005], 2010 British Association for Sexual and Relationship Therapy DOI: 10.1080/14681994.2010.518727 http://www.informaworld.com 416 M.L. Chivers Sexual and Relationship Therapy 417 418 M.L. Chivers Sexual and Relationship Therapy 419 420 M.L. Chivers Sexual and Relationship Therapy 421 422 M.L. Chivers Sexual and Relationship Therapy 423 424 M.L. Chivers Sexual and Relationship Therapy 425 426 M.L. Chivers Sexual and Relationship Therapy 427 428 M.L. Chivers Copyright of Sexual & Relationship Therapy is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder’s express written permission. However, users may print, download, or email articles for individual use. CHFD220 | LESSON 4 Sexual Arousal and Response Healthy Sexuality The brain is the key player in sexual arousal. When a sexual stimulus is encountered (e.g. visual, olfactory), the message is passed via nerves to the brain. Upon reaching the brain, these messages pass through the reticular activating system (RAS), either from or to the limbic system and the thalamus. The limbic system is where emotion evolves, and the thalamus serves as the switchboard, determining what to do with incoming messages. Next, the hypothalamus is activated, which in turn activates the autonomic nervous system (ANS) and the endocrine system through messages sent via nerves or substances released into the bloodstream. No two people respond the same way to sexual stimulation. What turns one person on may turn another person off. Hormones control sexual response to a given stimulus. Sexual hormones are produced in the testes in men and ovaries in women. Testosterone affects sexual interest, or libido. Aphrodisiacs are any substances that arouse sexual desire and/or enhance sexual response. Most do not work as promised and have potentially serious side effects. Artificial steroid hormones may not provide sexual benefits and may have harmful side effects. An-aphrodisiacs are substances that inhibit sexual desire. The Masters and Johnson Sexual Response Cycle Masters and Johnson described the human sexual response as consisting of four phases: 1) excitement, 2) plateau, 3) orgasm, and 4) resolution. Many non-genital physical changes accompany sexual arousal; for example, the nipples become erect, the skin flushes, muscles tense, breathing speeds up, the heart beats faster, and blood pressure rises. Genital changes also occur as a result of sexual arousal; for example, blood vessels become congested, the clitoris or the penis becomes erect, the vagina becomes wet, and Bartholin’s glands (female) and Cowper’s glands (male) secrete a few drops of fluid. The female sexual response is more varied than the male’s. Males generally move from excitement to plateau to orgasm and then to resolution. They can experience another orgasm but only after a refractory (recovery) period. Females sometimes experiences a sexual response cycle similar to that of males except they can have multiple orgasms without a refractory period. In addition, females can move from the excitement phase to plateau and, without having an orgasm, return to resolution; or they can experience rapid escalation from excitement to orgasm without experiencing a definitive plateau phase. Orgasm Orgasm is the release of sexual tension resulting in muscular contractions and ejaculation (at least in males). In males, it is generally followed by a refractory period in which orgasm is not possible. In females, orgasm can occur without a refractory period. Orgasm in females is preceded by the uterus increasing in size and elevating, the inner two-thirds of the vagina lengthening and expanding (sometimes called tenting), lubrication of the vaginal walls, engorgement of blood in the outer third of the vagina, and retraction of the clitoris under the clitoral hood. In males, orgasm is a two-stage process: emission and expulsion. Emission involves contractions of the vas deferens, the seminal vesicles, the prostate, and the external and internal urethral sphincters. Expulsion consists of a relaxing of the external urethral sphincter, contractions of the urethra and the muscles at the base of the penis and the anus, and the expelling of the ejaculate from the penis. Orgasms vary from person to person and from orgasm to orgasm within the same person. Sexual pleasure can be obtained without an orgasm and, in fact, striving for an orgasm (having it as the goal of the sexual encounter) may even interfere with sexual satisfaction. Simultaneous orgasm is undeniably an exciting event when it occurs, but it is only one of a wide range of satisfying sexual patterns. Setting it up as a goal can be dysfunctional. Learning Activity 4.1: Interactive Flashcards Review sexual arousal and response with Interactive Flashcards Conclusion “Sexual pleasure and satisfaction are both psychologically and physiologically based…pleasurable sexual stimulation will lead to an identifiable sexual response cycle. Knowing what this response cycle is can help you view your sexuality as a normal part of your functioning…” (Greenberg et al., 2014, p. 158). Bibliography Greenberg, J. S., Bruess, C. E., & Oswalt, S. B. (2014). Exploring the dimensions of human sexuality (5th ed.). Burlington, MA: Jones & Bartlett Learning. Image Citations “Typical sexual response cycles.” By Avril1975 – http://pbmo.files.wordpress.com/2012/04/sexual-response-cycle.png, Public Domain, Link “Gray690.” By Henry Vandyke Carter – Henry Gray (1918) Anatomy of the Human Body (See “Book” section below)Bartleby.com: Gray’s Anatomy, Plate 690, Public Domain, Link All additional graphics are either liscensed under Creative Commons CCO Public Domain or are stock photos from 123RF.