title: Brain response to visual sexual stimuli in heterosexual and homosexual males.
abstract: Although heterosexual and homosexual individuals clearly show differences in subjective response to heterosexual and homosexual sexual stimuli, the neurobiological processes underlying sexual orientation are largely unknown. We addressed the question whether the expected differences in subjective response to visual heterosexual and homosexual stimuli may be reflected in differences in brain activation pattern. Twenty-four healthy male volunteers, 12 heterosexuals and 12 homosexuals, were included in the study. BOLD signal was measured while subjects were viewing erotic videos of heterosexual and homosexual content. SPM02 was used for data analysis. Individual sexual arousal was assessed by subjective rating. As compared to viewing sexually neutral videos, viewing erotic videos led to a brain activation pattern characteristic for sexual arousal in both groups only when subjects were viewing videos of their respective sexual orientation. Particularly, activation in the hypothalamus, a key brain area in sexual function, was correlated with sexual arousal. Conversely, when viewing videos opposite to their sexual orientation both groups showed absent hypothalamic activation. Moreover, the activation pattern found in both groups suggests that stimuli of opposite sexual orientation triggered intense autonomic response and may be perceived, at least to some extent, as aversive.
authors.affiliation: Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Paul
authors.forename: Boris
authors.initials: B
authors.lastname: Schiffer
authors.forename: Thomas
authors.initials: T
authors.lastname: Zwarg
authors.forename: Tillmann H C
authors.initials: TH
authors.lastname: Krüger
authors.forename: Sherif
authors.initials: S
authors.lastname: Karama
authors.forename: Manfred
authors.initials: M
authors.lastname: Schedlowski
authors.forename: Michael
authors.initials: M
authors.lastname: Forsting
authors.forename: Elke R
authors.initials: ER
authors.lastname: Gizewski
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology; D004882:Erotica; D020010:Heterosexuality / Q000502:physiology*; D006716:Homosexuality / Q000502:physiology*; D006801:Humans; D007031:Hypothalamus / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D012725:Sexual Behavior / Q000502:physiology*