Human sexual response.

The human sexual response to sexually arousing stimuli is a motivational incentive-based cycle comprising subjective experience and physiologic changes. Clinical and empirical data support a circular model of overlapping phases of variable order. Brain imaging data of sexual arousal identify areas of cerebral activation and inhibition reflecting a complex network of cognitive, motivational, emotional, and autonomic components. Psychologic and biologic factors influence the brain's appraisal and processing of sexual stimuli to allow or disallow subsequent arousal. The sexual and non-sexual outcomes influence motivation to future sexual intimacy. Variability is marked both between individuals and within a person's sexual life, influenced by multiple factors, including stage of life cycle, mental health, and relationship happiness. Neurologic disease can interrupt the cycle at many points: by limiting motivation, reducing ability to attend to and feel sexual stimuli, and accomplishing the movements needed to stimulate and experience intercourse. Impairments to genital congestion, penile erection, and orgasm may also occur. Disease-associated changes to the interpersonal relationship and self-image plus frequently comorbid depression will tend to lessen motivation and temper the brain's appraisal of sexual stimuli, so precluding arousal. Therapy begins by explaining the sexual response cycle, clarifying the points of interruption in the patient's own cycle so as to guide treatment.