Study Reveals Sexually Dimorphic Brain Processing in Individuals with Low Sexual Desire

The study published in Scientific Reports showed that women and men with hypoactive sexual desire disorder (HSDD) -- that is, "distressingly" low sexual desire -- demonstrated dimorphic brain processing on functional MRI (fMRI).

"The data supports the ‘top-down’ theory of HSDD in women, whereas in men HSDD appears to be associated with different neurofunctional processes," the researchers wrote. In women, the ‘top-down’ theory of HSDD describes hyperactivity in higher-level cognitive brain regions, suppressing lower-level emotional/sexual brain areas.

The researchers note that therapies targeted at reducing hyperactivity in higher-cortical regions or boosting activation in lower-limbic regions could improve sexual function in HSDD women. However, there may be a different HSDD model in men, whereby the visual attention to the sexual cues is not relayed effectively to emotional centers involved in the sexual response.

HSDD is the most frequent sexual health complaint, affecting 8% of men and 10% of women. Previous research has found that in women the condition is caused by overactivity in higher-level cognitive brain regions that regulate self-monitoring, introspection, and guilt feelings, which in turn suppress lower-level emotional/sexual brain areas that regulate reward, emotion, and sexual processing. There is no clarity on whether this mechanism is at work in men.

It is essential to directly compare the neurobiological basis of HSDD in both sexes for further understanding of the disorder, which could lead to targeted and effective interventions and treatments. Considering this, Alexander N. Comninos, Section of Endocrinology and Investigative Medicine, Imperial College London, London, UK, and colleagues employed task-based functional MRI in 32 men and 32 women with HSDD to measure sexual-brain processing during sexual versus non-sexual videos, and psychometric questionnaires to evaluate sexual desire/arousal.

The study led to the following findings:

• Women had greater activation in higher-level and lower-level brain regions, compared to men.
• Indeed, women who had greater hypothalamic activation in response to sexual videos reported higher psychometric scores in the motivational (r = 0.56), evaluative (r = 0.55), and physiological (r = 0.57) domains of sexual desire and arousal after watching the sexual videos in the scanner.
• There were no similar correlations in men.

"Taken together, this is the first direct comparison of the neural correlates of distressing low sexual desire between men and women," the researchers wrote.

"The data supports the ‘top-down’ theory of HSDD in women, whereas HSDD, in men, appears to be associated with different neurofunctional processes," they concluded.

Reference:

Ertl, N., Mills, E. G., Wall, M. B., Thurston, L., Yang, L., Suladze, S., Hunjan, T., Phylactou, M., Patel, B., Bassett, P. A., Howard, J., Rabiner, E. A., Abbara, A., Goldmeier, D., Comninos, A. N., & Dhillo, W. S. (2024). Women and men with distressing low sexual desire exhibit sexually dimorphic brain processing. Scientific Reports, 14(1), 1-10. https://doi.org/10.1038/s41598-024-61190-4