At the second glance: stability of neural responses toward visual sexual stimuli.

ABSTRACT

INTRODUCTION: Studies investigating the neural responses toward sexual stimuli can provide an important basis for further understanding disorders of sexual functioning. Although our knowledge of the neural correlates of sexual stimulus processing has increased considerably in the last decade, the stability of the observed effects in studies on neural sexual responses has been rather neglected. AIMS: The current study aimed to test the stability of behavioral and neural responses to visual sexual stimuli in men and women over a time span of 1 to 1.5 years. To disentangle valence and arousal-related aspects of sexual stimulus processing, we employed not only sexual and neutral, but also positive and negative emotional stimuli. METHODS: A sample of 56 subjects (24 women) was assessed twice, with an interval of 1 to 1.5 years between assessments. During a functional magnetic resonance imaging (fMRI) session, participants passively viewed sexual, neutral, positive, and negative emotional pictures. Pictures were presented in 24 blocks of five pictures each. Every block was rated immediately after its presentation with respect to valence, arousal, and sexual arousal. MAIN OUTCOME MEASURES: Blood oxygen level dependent (BOLD) responses measured by fMRI and stimulus ratings. RESULTS: fMRI analyses revealed a distributed network involved in the processing of sexual stimuli, with large parts of this network being consistently activated at both assessment points. Nucleus accumbens, anterior cingulate, occipital and parietal cortex showed the most robust results with respect to group stability. Responses of anterior cingulate, orbitofrontal, parietal and occipital cortex showed interindividual stability. Gender differences were restricted to a few regions of interest. CONCLUSIONS: Our data indicate stability of neural responses toward sexual stimuli not only on the group but also on the individual level. Activation of parietal and occipital cortex might reflect a trait like character of attention related responses toward sexual stimuli.