Neural Correlates of Sexual Orientation in Heterosexual, Bisexual, and Homosexual Men and WomenPublic Deposited
Psychophysiological investigations of human sexuality have revealed more complexity than might be naively assumed. The sexual arousal patterns of heterosexual and homosexual men are relatively straightforward, with both groups showing substantial responses to erotic stimuli of their preferred sex and much smaller responses to their nonpreferred sex. Bisexual men, in contrast, have shown significantly more nonspecific response profiles in some studies, but not in others. Surprisingly, women also demonstrate nonspecific patterns of genital responding, with homosexual women exhibiting somewhat more biased responding towards their preferred gender category of erotic stimuli. Here, I describe a research program consisting of three studies that examined patterns of brain activity in response to erotic stimuli in heterosexual, bisexual, and homosexual men and women. The main data analytic approach focused on the ventral striatum as an a priori region of interest for measuring reward-related brain activity, with differential evoked responses to male and female stimulus classes interpreted as a proxy for relative androphilic and gynephilic preferences, respectively. While support was found for much of the genital psychophysiology literature, the ecological significance of lab-measured genital arousal remains difficult to interpret in some cases, particularly in women. Further studies should use a broader variety of classes of stimuli and experimental conditions to investigate this fundamental aspect of human psychology.