fMRI Localization of Spinal Cord Processing Underlying Female Sexual Arousal

Abstract

Using functional magnetic resonance imaging, the authors aimed to determine the roles of the human spinal cord in mediating sexual responses in women. Functional magnetic resonance imaging of the entire lower thoracic, lumbar, and sacral spinal cord was performed using a sexual stimulation paradigm designed to elicit psychological and physical components of sexual arousal. Responses were measured in 9 healthy adult women during 3 consecutive conditions: (a) erotic audiovisual, (b) manual clitoral, and (c) audiovisual plus manual stimulation. Functional magnetic resonance imaging results in healthy subjects demonstrate that this method is sensitive for mapping sexual function in the spinal cord, and identify several key regions involved in human sexual response, including the intermediolateral cell column, the dorsal commissural nucleus, and the sacral parasympathetic nucleus. Using spinal functional magnetic resonance imaging, this study identified many of the spinal cord regions involved in female sexual responses. Results from audiovisual and manual clitoral stimulation correspond with previous data regarding lumbar and sacral neurologic changes during sexual arousal. This study provides the first characterization of neural activity in the human spinal cord underlying healthy female sexual responses and sets a foundation for future studies aimed at mapping changes that result from sexual dysfunction, spinal cord trauma or disease.

Notes

Note that fMRI responses are thought to reflect changes in the mean synaptic input to a given area, as opposed to the spiking activity (output) of the neurons located there (Figley & Stroman, 2011; Logothetis et al., 2001), whereas c-Fos staining codes for a transcription factor that is thought to mediate long-term changes in neural functioning (Kovacs, 2008).