Androgene verändern die Hirnantworten auf sexuelle Stimuli bei Frau-zu-Mann-Transsexuellen: Eine fMRT Studie

Interpersonal and intrapersonal differences in brain responses to sexual stimuli have been linked with individuals’ testosterone levels. However, it remains unclear how hormones modulate brain functions underlying sexual arousal. In order to assess the effects of chronic hormonal treatment, we used functional magnetic resonance imaging in a group of female-to-male transsexuals before and during androgen therapy while they watched a set of pictures representing dressed or nude (erotic content) men or women (sex information). A broad network of cortical and subcortical regions were activated during the processing of erotic stimuli (nude vs. dressed), including the insula, amygdala, and hypothalamus. The insula activity in response to erotic male stimuli decreased over the initial 4 months of hormonal therapy. In the following 8 months, the insula response to erotic female stimuli increased. In other words, long-term androgen administration makes the brain more “male” by reducing the sexual arousal caused by male stimuli and amplifying that caused by female stimuli.