Brain activation during vaginocervical self-stimulation and orgasm in women with complete spinal cord injury: fMRI evidence of mediation by the Vagus nerves

Department of Psychology, Rutgers, The State University of New Jersey, Newark, NJ 07102, USA.
Brain Research (Impact Factor: 2.84). 11/2004; 1024(1-2):77-88. DOI: 10.1016/j.brainres.2004.07.029
Source: PubMed


Women diagnosed with complete spinal cord injury (SCI) at T10 or above report vaginal-cervical perceptual awareness. To test whether the Vagus nerves, which bypass the spinal cord, provide the afferent pathway for this response, we hypothesized that the Nucleus Tractus Solitarii (NTS) region of the medulla oblongata, to which the Vagus nerves project, is activated by vaginal-cervical self-stimulation (CSS) in such women, as visualized by functional magnetic resonance imaging (fMRI). Regional blood oxygen level-dependent (BOLD) signal intensity was imaged during CSS and other motor and sensory procedures, using statistical parametric mapping (SPM) analysis with head motion artifact correction. Physiatric examination and MRI established the location and extent of spinal cord injury. In order to demarcate the NTS, a gustatory stimulus and hand movement were used to activate the superior region of the NTS and the Nucleus Cuneatus adjacent to the inferior region of the NTS, respectively. Each of four women with interruption, or "complete" injury, of the spinal cord (ASIA criteria), and one woman with significant, but "incomplete" SCI, all at or above T10, showed activation of the inferior region of the NTS during CSS. Each woman showed analgesia, measured at the fingers, during CSS, confirming previous findings. Three women experienced orgasm during the CSS. The brain regions that showed activation during the orgasms included hypothalamic paraventricular nucleus, medial amygdala, anterior cingulate, frontal, parietal, and insular cortices, and cerebellum. We conclude that the Vagus nerves provide a spinal cord-bypass pathway for vaginal-cervical sensibility in women with complete spinal cord injury above the level of entry into spinal cord of the known genitospinal nerves.

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    • "Woodburne reported earlier on the uncertain termination of the vagal and pelvic parasympathetic territories and suggested that there might be an overlap in the distribution of both in the autonomic plexuses (Woodburne, 1956). Also, there is an evidence for the existence of pelvic–vagal afferent pathways (Kaddumi et al., 2012; Komisaruk et al., 2004). Despite the fact that our study did not focus on the neurochemical composition of the vagus nerve, the abundant TH expression was a remarkable finding. "
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    ABSTRACT: The superior hypogastric plexus (SHP) is an autonomic plexus, located ventrally to the abdominal aorta and its bifurcation, innervating pelvic viscera. It is classically described as being composed of merely sympathetic fibres. However, post-operative complications after surgery damaging the peri-aortic retroperitoneal compartment suggest the existence of parasympathetic fibres. This immunohistochemical study describes the neuroanatomical composition of the human mature SHP. Eight pre-determined retroperitoneal localizations including the lumbar splanchnic nerves, the SHP and the HN were studied in four human cadavers. Control tissues (white rami, grey rami, vagus nerve, splanchnic nerves, sympathetic ganglia, sympathetic chain and spinal nerve) were collected to verify the results. All tissues were stained with haematoxylin and eosin and antibodies S100, tyrosine hydroxylase (TH), vasoactive intestinal peptide (VIP) and myelin basic protein (MBP) to identify pre- and postganglionic parasympathetic and sympathetic nerve fibres. All tissues comprising the SHP and hypogastric nerves (HN) showed isolated expression of TH, VIP and MBP, revealing the presence of three types of fibres: postganglionic adrenergic sympathetic fibres marked by TH, unmyelinated VIP-positive fibres and myelinated preganglionic fibres marked by MBP. Analysis of control tissues confirmed that TH, VIP and MBP were well usable to interpret the neurochemical composition of the SHP and HN. The human SHP and HN contain sympathetic and most likely postganglionic parasympathetic fibres. The origin of these fibres is still to be elucidated, however surgical damage in the peri-aortic retroperitoneal compartment may cause pelvic organ dysfunction related to both parasympathetic and sympathetic denervation. Copyright © 2015 Elsevier B.V. All rights reserved.
    Autonomic Neuroscience 02/2015; 189. DOI:10.1016/j.autneu.2015.02.001 · 1.56 Impact Factor
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    • "Their research was the underpinning for much subsequent investigation (Levin, 2001) and has informed social and political commentaries on female sexuality ever since (e.g., Hite, 1976; Lloyd, 2005). However, with the neurological (e.g., Komisaruk et al., 2004), anatomical (e.g., O'Connell et al., 1998, 2005; Zaviačičet al., 1988), and behavioral (e.g., Lightfoot-Klein , 1984; McCaughey & French, 2001) data subsequently available to us, their findings stand in need of revision. Indeed, there now seem grounds for arguing that not all female orgasms are the same. "
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    Archives of Sexual Behavior 10/2012; 41(5):1145-60. DOI:10.1007/s10508-012-0001-0 · 3.53 Impact Factor
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    • "The vagus nerve is the main constituent of the parasympathetic branch of the autonomic nervous system and bypasses the spinal cord. Consequently, women with spinal cord injuries below T-10 (thus, without sensory connection between clitoris and brain, as well as without hypogastric, pelvic and pudendal nerve connection between vagina and brain) can attain orgasms (verified by fMRI plus self-report) by vaginocervical stimulation (Komisaruk et al., 2004). The women with spinal cord injuries below T-10 do not present much movement artifact in fMRI measurements of orgasm (bypassing the problem that Prause claims). "
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