Neurophysiology and Sexual Function

Neurophysiology is a dynamic and highly complex system of neurological connections and interactions that allow for bodily performance. When all of those connections are working correctly, our bodies can function at optimal levels. When there is a break or injury to those connections, dysfunction results but amazingly in some circumstances, our bodies have work arounds to allow for certain functions to continue working.

If we take the sexual neural control system of the male, for instance, a perfect example of this can be described. Many men were injured fighting in World War II. During their time in battle, many experienced spinal cord injuries. Some of these injuries were severe resulting in complete spinal cord damage at level of injury. A physician, Herbert Talbot, in 1949, documented his examination of 200 men with paraplegia. Two thirds of the men were surprisingly able to achieve erections and some were able to experience vaginal penetration and orgasm. Much of their basic functionality had been lost however amazingly there was preservation of erectile function.

The reason these men with paraplegia were able to maintain erectile or orgasm functionality is due to the physiological function in the sacral spinal cord. A reflex arc is present in this region. The definition of a reflex arc is a nerve pathway that has a reflexive action involving sensory input from a peripheral somatic or autonomic nerve synapsing to a relay neuron or interneuron in the sacral cord segment then synapsing to a motor nerve for output to the muscular region. These messages do not need to travel up the spinal cord to the brain in order to be activated. Instead they work within a ‘loop’ at the sacral spinal cord level. In the case of spinal cord injury, erectile function as well as other functions controlled by reflex arcs, can be preserved.

For women, the same is true. In order for a female to have engorgement of the clitoris or orgasm, the sacral spinal reflex arc needs to be intact. If a woman experiences a spinal cord injury above the sacral region, the ability to have a reflexive orgasm within the sacral spinal reflex arc will remain.

The sacral reflex arc also plays an important role in activation of the pelvic floor muscles during the sexual response cycle. During genital stimulation in both the male and female, the bulbospongiosus or bulbocavernosus begins to activate in a reflexive pattern to hinder the outflow of blood from the region which facilitates erectile tissue of the penis and clitoris to become erect. This can then be followed by rhythmic reflexive contractions of the pelvic floor musculature during orgasm.

To learn more about the implications that neurologic disorders can have on the sexual system, please join us for Neurologic Conditions and Pelvic Floor Rehab, coming to Grand Rapids, MI in September.

Goldstein, I. (2000). Male sexual circuitry. Scientific American, 283(2), 70-75.
Sipski, M. L. (2001). Sexual response in women with spinal cord injury: neurologic pathways and recommendations for the use of electrical stimulation. The journal of spinal cord medicine, 24(3), 155-158.
Wald, A. (2012). Neuromuscular Physiology of the Pelvic Floor. In Physiology of the Gastrointestinal Tract (Fifth Edition)(pp. 1023-1040).