Figure 3.

a: Group-based composite view of the clitoral, vaginal and cervical activation sites, all in the medial paracentral lobule, but regionally differentiated. We interpret this as due to the differential sensory innervation of these genital structures, i.e., clitoris: pudendal nerve, vagina: pelvic nerve, and cervix: hypogastric and vagus nerves (e.g., [14]).

b: Nipple self-stimulation activated not only the thoracic region, but also unexpectedly, the genital region of the medial paracentral lobule. Shown are superimposed responses to nipple and genital self-stimulation in three participants. Note the congruence between activation produced by stimulation of nipple and cervix (left panel), nipple, cervix and clitoris (center panel), and nipple, vagina, cervix and clitoris (right panel). Not unexpectedly, cervical self-stimulation activated the groin region (center panel). However, it is surprising that vaginal self-stimulation activated the thoracic nipple region (center panel), and nipple self-stimulation activated the groin sensory region (left panel). Color coding: nipple (white), cervix (yellow), clitoris (green), vagina (red, or when congruent with nipple - pink).

c: Three-axis view of the response to the nipple self-stimulation in the case of the center image of Figure 3(b) (downward pointing blue arrow).