PB9. The ‘functional magnetic resonance imaging’ (fMRI) as a meaningful tool for the differentiation of sexual preferences

Abstract

Context The research network ‘ Ne ural mechanisms u nderlying p edophilia and sexual offending against children: origins, assessment and therapy’ investigates mechanisms of sexual abuse of children and pedophilia by means of fMRI imaging, clinical interviews, and psychological testing. While pedophiles’ sexual fantasies refer to pre-pubertal children of the first Tanner Stage ( Tanner, 1978 ), hebephilic men prefer partners who are in puberty (Tanner Stage 2–3) ( Blanchard et al., 2009 ). But whether hebephilia can be seen as an independent entity is still controversial. Our previous research showed that the functional brain response patterns to sexual stimuli contain sufficient information to identify pedophiles (compared to teleiophiles) with a mean accuracy of 95% ( Ponseti, 2012 ). However, the treatment relies on a precise measurement of the sexual orientation. To this end, we tested whether standard second level analysis of brain responses to sexual stimuli and/ or whole brain calculations of BOLD-responses to sexual stimuli are useful to differentiate between pedophiles and hebephiles. Design During fMRI, participants (n = 328) were shown same- and opposite-sex images of nude children and adults in Tanner stages 1–5. The images were each shown for one second with a variable inter-stimulus interval of two seconds on average. The previous classification was based on clinical interviews, self-reported details (like sexual/masturbating fantasies) or according to criminal/medical records. We calculated differences in BOLD-signals for the sexual stimuli in the corresponding contrast images (i.e.one hebephiles’ contrast image was defined as ‘pubertal boy/girl’), as well as a whole brain functional BOLD response to each stimulus category. Results Preference specific brain activity was found in hebephilic as well in pedophilic participants in areas known to be involved in sexual stimulus processing. Conclusion Here we present evidence that whole brain response calculation provides a meaningful measure of sexual preferences in healthy and in paraphilic males. Particularly, response differences between pedophilic and hebephilic participants provide evidence that these clinical categories differ at the level of brain function.