title: Neural activation toward erotic stimuli in homosexual and heterosexual males.
abstract: BACKGROUND
  Studies investigating sexual arousal exist, yet there are diverging findings on the underlying neural mechanisms with regard to sexual orientation. Moreover, sexual arousal effects have often been confounded with general arousal effects. Hence, it is still unclear which structures underlie the sexual arousal response in homosexual and heterosexual men.
  
  
  OBJECTIVE
  Neural activity and subjective responses were investigated in order to disentangle sexual from general arousal. Considering sexual orientation, differential and conjoint neural activations were of interest.
  
  
  METHODS
  The functional magnetic resonance imaging (fMRI) study focused on the neural networks involved in the processing of sexual stimuli in 21 male participants (11 homosexual, 10 heterosexual). Both groups viewed pictures with erotic content as well as aversive and neutral stimuli. The erotic pictures were subdivided into three categories (most sexually arousing, least sexually arousing, and rest) based on the individual subjective ratings of each participant.
  
  
  METHODS
  Blood oxygen level-dependent responses measured by fMRI and subjective ratings.
  
  
  RESULTS
  A conjunction analysis revealed conjoint neural activation related to sexual arousal in thalamus, hypothalamus, occipital cortex, and nucleus accumbens. Increased insula, amygdala, and anterior cingulate gyrus activation could be linked to general arousal. Group differences emerged neither when viewing the most sexually arousing pictures compared with highly arousing aversive pictures nor compared with neutral pictures.
  
  
  CONCLUSIONS
  Results suggest that a widespread neural network is activated by highly sexually arousing visual stimuli. A partly distinct network of structures underlies sexual and general arousal effects. The processing of preferred, highly sexually arousing stimuli recruited similar structures in homosexual and heterosexual males.
authors: Bender Institute of Neuroimaging, Justus-Liebig-University Giessen, Germany. kagerer@psychol.uni-giessen.de
authors: Sabine
authors: S
authors: Kagerer
authors: Tim
authors: T
authors: Klucken
authors: Sina
authors: S
authors: Wehrum
authors: Mark
authors: M
authors: Zimmermann
authors: Anne
authors: A
authors: Schienle
authors: Bertram
authors: B
authors: Walter
authors: Dieter
authors: D
authors: Vaitl
authors: Rudolf
authors: R
authors: Stark
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D001921:Brain / Q000502:physiology*; D004882:Erotica / Q000523:psychology; D059907:Functional Neuroimaging; D020010:Heterosexuality / Q000502:physiology* / Q000523:psychology; D018451:Homosexuality, Male / Q000523:psychology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012725:Sexual Behavior / Q000502:physiology* / Q000523:psychology; D055815:Young Adult