Neural and Hormonal Correlates of Sexual Arousal in Transgender Persons.

Whereas mounting work has begun to document the neural correlates underlying sexual arousal (SA) in humans, the associations between gender identity and the brain correlates of SA as well as their hormonal contributions remain unknown. This study investigated neural activation to sexual arousal in transgender and cisgender persons. 20 transgender men and 19 transgender women (TW) already living in their identified gender were compared to 21 cisgender men (CM) and 19 cisgender women. Participants viewed erotic and neutral video clips while undergoing 3 Tesla magnetic resonance imaging. Group-specific brain activation, brain functional connectivity, and brain-hormone associations within the neurophenomenological model of sexual arousal (Stoleru et al, 2012). Consistent with the model, participants activated most of its components. However, between-group differences were mostly showing larger activation for CM relative to any of the other 3 groups. Moreover, functional connectivity analyses (psychophysiological interactions) indicated unique patterns for CM, cisgender women, and TW in how different components of SA communicated with one another. Finally, androgens in transgender men and estrogens in TW correlated negatively with parietal cortex and primary (sensori-) motor regions, respectively, while CM showed positive correlations of androgens with parietal cortex, somatosensory regions, and the insula. Data provide information on neurobiological changes in sexual arousal during treatment with gender-affirming hormone therapy. Although a limitation is the lack of pretreatment data, the present study provides comprehensive information including brain activation, functional connectivity, and hormonal associations in a large sample. The results highlight a complex picture of the neural correlates of SA in gender identity and sex assigned at birth. Mueller SC, Wierckx K, T'Sjoen G. Neural and Hormonal Correlates of Sexual Arousal in Transgender Persons. J Sex Med 2020;17:2495-2507.