Unmyelinated tactile cutaneous nerves signal erotic sensations

J Sex Med. 2015 Jun;12(6):1338-45. doi: 10.1111/jsm.12905. Epub 2015 May 12.


Introduction: Intrapersonal touch is a powerful tool for communicating emotions and can among many things evoke feelings of eroticism and sexual arousal. The peripheral neural mechanisms of erotic touch signaling have been less studied. C tactile afferents (unmyelinated low-threshold mechanoreceptors), known to underpin pleasant aspects of touch processing, have been posited to play an important role.

Method: In two studies, we investigated the relationship between C tactile activation and the perception of erotic and pleasant touch, using tactile brushing stimulation. In total, 66 healthy subjects (37 women, age range 19-51 years) were examined. In study 1 (n = 20), five different stroking velocities were applied to the forearm and the inner thigh. The participants answered questions about partnership, mood, and touch. In study 2 (n = 46), the same five stroking velocities were applied to the forearm. The participants answered questions about partnership, touch, and sexuality.

Results: Both touch eroticism and pleasantness were rated significantly higher for C tactile optimal velocities compared with suboptimal velocities. No difference was found between the ratings of the thigh and the forearm. The velocity-dependent rating curves of pleasantness, intensity, and eroticism differed from each other. Pleasantness was best explained by a quadratic fit, intensity by a linear fit, and eroticism by both. A linear transformation of pleasantness and intensity predicted the observed eroticism ratings reliably. Eroticism ratings were negatively correlated with length of relationship.

Conclusion: Touch was rated most erotic when perceived as pleasant and weak. In human hairy skin, perception of pleasantness is correlated with the firing rate of C tactile afferents, and perception of intensity is correlated with the firing rate of Aβ afferents. Accordingly, eroticism may be perceived most readily for touch stimuli that induce high activity in C tactile fibers and low activity in Aβ fibers.

Keywords: C Tactile; Erotic; Periphery; Pleasantness; Somatosensory; Touch.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Affect
  • Arousal / physiology*
  • Emotions
  • Female
  • Forearm / innervation
  • Humans
  • Male
  • Mechanoreceptors / physiology*
  • Middle Aged
  • Nerve Fibers, Unmyelinated / physiology*
  • Physical Stimulation / methods*
  • Skin / innervation*
  • Surveys and Questionnaires
  • Thigh / innervation
  • Touch / physiology*