Haemodynamic Brain Response to Visual Sexual Stimuli is Different between Homosexual and Heterosexual Men

Abstract

The underlying neurobiological factors involved in sexual orientation are largely unknown. This study investigated whether neural circuits or different cognitive processes accounted for differences in brain activation in 14 heterosexual and 14 homosexual males. Brain scans were undertaken in each subject using functional magnetic resonance imaging while they viewed different sexual stimuli, i.e. heterosexual couple stimuli (HCS), gay couple stimuli (GCS), lesbian couple stimuli (LCS) and neutral stimuli (NS). Ratings of sexual attractiveness of the stimuli were assessed. Subjective sexual arousal was induced by HCS and GCS in heterosexual and homosexual men, respectively. Sexual disgust was induced by GCS and LCS in heterosexual and homosexual men, respectively. Compared with viewing NS, viewing sexual stimuli induced significantly different brain activations, most of which had the characteristics of cognitive processes. These observations suggest that different cognitive patterns may be the major cause of different subjective responses to sexual stimuli between heterosexual and homosexual men.

A pilot study on the sexual side effects of finasteride as related to hand preference for men undergoing treatment of male pattern baldness

“…Hand preference also appears to be related to other prenatally influenced variables, including the cognitive profile of the individual. In this respect, handedness, cognitive profile, gonadal hormones and sexual orientation all appear to be interrelated [8–11].…”

Gender difference in brain activation to audio-visual sexual stimulation; do women and men experience the same level of arousal in response to the same video clip?

“…The activated brain areas demonstrated by fMRI during sexual visual stimulation are the frontal lobe, cingulate gyrus, insula, corpus callosum, caudate nucleus, globus pallidus, inferior temporal lobes and thalamus. [6][7][8][9][10]13 Arnow et al 14 used fMRI to confirm the activated brain area during penile erection by visually evoked sexual stimulation, and reported that activation of the right insula and inferior portion of the insula, caudate nucleus, cingulate gyrus, posterior temporal lobe and hypothalamus is associated with penile tumescence. However, data addressing sexually aroused females are relatively limited.…”

“…The majority of other fMRI studies of sexual arousal report activation of the amygdala, thalamus and hypothalamus in both men and women, although to different degrees. [6][7][8][9][10][11][12][13] Activation of the amygdala and hypothalamus are more prominent in men than in women when presented with the same sexual stimuli, even when women reported greater sexual arousal. 11,12 The amygdala and thalamus may have a greater role in mediating visual stimuli in male sexual behavior.…”

“…Many contributing factors can affect sexual preference, such as education, social relationships, cultural background, personal sexual preferences, personal history or cognitive processes. 9,10 It is not yet clear whether differences in preference between the genders are acquired or innate. 9 The presence of those differences should not be ignored.…”

“…Historically, there have been a few studies of MRI-based brain region activation in response to visual sexual stimuli in different genders or sexual preferences. [6][7][8][9][10] However, only a few previous studies reported gender differences in brain activation response to certain sexual stimuli. 11,12 Although audio-visual stimulation (AVS) is widely used in the clinical setting to induce sexual arousal to examine male or female sexual dysfunction, personal or gender preference to such stimuli-inducing sexual arousal has not been considered, despite discrete sexual preferences between men and women in general AVS examination settings.…”