Sensory-Tactile Functional Mapping and Use-Associated Structural Variation of the Human Female Genital Representation Field

Abstract

The precise location of the human female genital representation field in the primary somatosensory cortex (S1) is controversial and its capacity for use-associated structural variation as a function of sexual behavior remains unknown. We used a functional magnetic resonance imaging (fMRI)-compatible sensory-tactile stimulation paradigm to functionally map the location of the female genital representation field in 20 adult women. Neural response to tactile stimulation of the clitoral region (vs right hand) identified individually-diverse focal bilateral activations in dorsolateral areas of S1 (BA1–BA3) in alignment with anatomic location. We next used cortical surface analyses to assess structural thickness across the 10 individually most activated vertices per hemisphere for each woman. We show that frequency of sexual intercourse within 12 months is correlated with structural thickness of the individually-mapped left genital field. Our results provide a precise functional localization of the female genital field and provide support for use-associated structural variation of the human genital cortex. SIGNIFICANCE STATEMENT We provide a precise location of the human female genital field in the somatosensory cortex and, for the first time, provide evidence in support of structural variation of the human genital field in association with frequency of genital contact. Our study represents a significant methodological advance by individually mapping genital fields for structural analyses. On a secondary level, our results suggest that any study investigating changes in the human genital field must map the field individually to achieve sufficient precision. Our results pave the way for future research into the plasticity of the human genital cortex as a function of normal or adverse experience as well as changes in pathologic conditions, i.e., sexual dysfunction, sexual deviation, or sexual risk-taking behavior.

Topological Maps and Brain Computations From Low to High

“…Most unusually, we found a small bilateral superior central sulcus auditory area (low to high frequencies from anterior-lateral to posterior-medial) embedded within Brodmann area 3a/3b (3aud). It occupies about half of a small no-response gap in our somatomotor mapping data between the representation of the ‘hand’ (which includes the arm and stomach) and the ‘foot’ (which includes the thigh and leg) that likely corresponds to the representation of the genitalia ( Knop et al, 2021 ) and/or respiratory muscles ( McKay et al, 2003 ), both of which we did not specifically stimulate. Auditory responses in this region are not unprecedented (see Tierney et al, 2012 , their Figure 2).…”

Hearing, touching, and multisensory integration during mate choice

“…Insula genital touch activation is intriguing in the light of discriminative vs. affective touch as it is to date unknown whether CT fibers can be found in the genitals (Georgiadis and Kringelbach, 2012 ). Interestingly a recent human fMRI study described that the somatosensory region representing the clitoris is larger in women who reported to have higher frequencies of sexual intercourse in the past year and during the onset of their sexual activity (Knop et al, 2022 ).…”

Practitioner Review: Neurobiological consequences of childhood maltreatment – clinical and therapeutic implications for practitioners

“…In contrast, other groups of maltreated individuals exposed to emotional abuse showed relative thinning in cortical regions relevant to self‐evaluation and self‐awareness (Heim et al., 2013). While these sensory adaptations may protect a child from fully processing frightening experiences, later they may lead to problems, such as impaired sexual response (Knop et al., 2022) when sensory awareness is needed.…”