SFEIES24 Poster Presentations Reproductive Endocrinology (15 abstracts)
1Section of Endocrinology and Investigative Medicine, Imperial College London, London, United Kingdom; 2Invicro, London, United Kingdom; 3Statsconsultancy, Ltd, Amersham, United Kingdom; 4Jane Wadsworth Sexual Function Clinic, Imperial College Healthcare NHS Trust, London, United Kingdom
Background: Hypoactive Sexual Desire Disorder (HSDD) affects 10% of women and 8% of men. In women, the top-down neurofunctional HSDD model suggests that hyperactivation of higher-level cognitive brain regions suppresses lower-level sexual brain activity in response to erotic cues, impairing sexual function. Conversely, the neurodysfunction in men with HSDD is not fully characterised and unlike in women where therapies exist, there are no licensed pharmacotherapeutics. Here, we present the first direct comparison of the neural bases between women and men with HSDD.
Methods: Thirty-two premenopausal women and 32 men with HSDD underwent task-based functional MRI (fMRI) measuring sexual brain activity during erotic vs control (exercise) videos. Participants completed psychometric questionnaires, providing behavioural relevance for brain-activity changes.
Results: Women exhibited greater activation in higher-level cortical (e.g., inferior frontal gyrus) and lower-level limbic regions (e.g., amygdala) in response to erotic videos compared to men. These findings, coupled with inverse correlations between limbic-region activation and HSDD severity, support the top-down mechanism underlying HSDD in women. Conversely, men exhibited lower activation in both higher-cortical and lower-limbic regions, alongside heightened visual cortex activity compared to women, suggesting a disconnect between visual sensitivity to erotic cues and the limbic system, serving as an underlying mechanism for HSDD in men. Moreover, women who had greater hypothalamic activation in response to erotic videos, displayed improved psychometric scores in the evaluative (r = 0.55, P = 0.001), motivational (r = 0.56, P = 0.003), and physiological (r = 0.57, P = 0.0006) domains of sexual desire/arousal.
Discussion: This is the first direct comparison of the neural bases of HSDD between women and men. While supporting the top-down mechanism in women, it suggests different neurodysfunctional processes in men, highlighting a potential functional disconnection between sensory/attention and sexual centres. Identifying sexual dimorphisms in low sexual desire has key clinical implications relevant to the development of therapeutics for people living with HSDD.