Just what is an orgasm? Depending on whether you ask a psychologist, biologist, sacred sexual practitioner, or reflexologist—the answer will be different. In case you don't know, several parallel and intersecting truths can exist all at once! As the title of this article implies, though, human nerve wiring has a pretty big role in what we experience as orgasms.
Specific vs. Non-Specific Erogenous Zones
You know that slightly ticklish spot on the back and sides of your neck that send pleasurable shivers through your body when stroked just the right way by just the right person? Or perhaps that happens on your inner thighs? Well, wherever that spot may be, that is called a non-specific erogenous zone. It's an erogenous zone because of the way it makes you feel, but it is non-specific in that the density of nerves in that area are similar to the rest of the skin on your body, therefore those pleasurable sensations you are experiencing are largely learned behaviors. [Source: The Mayo Clinic]
Specific erogenous zones are mucous membranes that are not only innervated with a significantly denser nerve supply, but those nerves are also closer to the surface of the skin, making them much more accessible and sensitive to the touch. These areas include the inner and, to some extent, the outer labia, clitoris, penis, prepuce (foreskin- of both the clitoris and penis), nipples, lips, mouth, etc. The clitoris has around 8,000 nerve endings! That's compared to between 3,500 and 20,000 nerve endings in the male penis (depending on the study).
Okay, I'll dial back the dramatic proclamations because, really, different sources say dramatically different things about the amount and type of nerve endings around the body. Some sources claim that the hands or bottoms of the feet contain the most nerve endings. In some ways, it's like comparing apples to oranges because it's not simply the amount of nerve endings that affect our subjective experiences but how they are networked throughout our body and how our brain decides to respond to the stimulation of these nerves.
Different Strokes For Different Folks
Because we're all so different, coming up with a universal description of an orgasm is impossible. The one thing that most people can agree on is that it's an incredibly, intensely pleasurable experience. -Shanna Freeman
Neural pathways play another large role in the phenomenon that is our orgasm. The main pathways that are in play are:
"Hypogastric Nerve - transmits from the uterus and the cervix in women and from the prostate in men
Pelvic Nerve - transmits from the vagina and cervix in women and from the rectum in both sexes
Pudendal Nerve - transmits from the clitoris in women and from the scrotum and penis in men
Vagus Nerve - transmits from the cervix, uterus and vagina" [Source: What happens in the brain during an orgasm? By Shanna Freeman published in How Stuff Works]
(An interesting, but disappointing, factoid about the pudendal nerve is that it derives its name from pudenda, which literally translates from its Latin origin as "to be ashamed of.")
All of these neural pathways, except for the vagus nerve, travel through the spinal cord. This exception is important because this may explain why individuals with severed spinal cords can still experience orgasms. In fact, it was research conducted in 2004 on a group of women with severed spinal cords that precipitated the realization that the vagus nerve innervates all the way down to the lower torso, because many of them were able to experience orgasm with direct stimulation to their cervix.
Of course, this does not explain why some of us sometimes experience electricity in our feet during those special full-body orgasms. And it especially doesn't explain why people often experience orgasmic pleasure in and/or from phantom limbs (limbs that have been amputated or otherwise lost) let alone any sensation whatsoever from these missing limbs. Perhaps, for similar reasons, when I "strap-on" a silicone dildo, I can experience physical pleasure through my synthetic bodily extension. (And I'm not the only one).
Science has a way of chasing experiential truths with tidy (or not-so-tidy) explanations, and so they speculate that there is a type of wire crossing that may occur in the sensory and motor cortices of the brain. For instance, the part of our brain that receives pleasurable signals from our genitals may share some of those pleasurable signals with an adjacent region of the brain that receives signals from the foot, or what used to be the foot. What would all the nerves in the world mean to us without our brain, after all?
Our Brain Is Our Largest "Sex Organ"
Orgasm lights up more than just your loins. -Shanna Freeman
During sexual arousal and climactic orgasms, respectively, large parts of our brain light up with a flurry of activity, while other parts completely deactivate. There is a small region of the brain, just behind the left eye (lateral orbitofrontal), that completely deactivates. I find this particularly interesting in the context of Tantric eye gazing where a spiritually bonding activity involves partners staring into each others left eye- the receptive window into our soul. This is not necessarily practiced while engaged in sexual union, but often is.
Another interesting correlation is that during orgasm, 95% of our brain resembles that of the brain of somebody who is on heroin. Not only are orgasms healthier, though, they are a much less expensive habit to maintain in the long run.
While there aren't too many differences between men and women's brains in terms of what goes on during sex, there have been some specific studies conducted at the University of Groningen in the Netherlands that demonstrated a general difference between their female and male subjects when it came to the amygdala and hippocampus- the region of the brain that deals with fear and anxiety. Generally speaking, this region showed much less activity in the women during orgasm. In other words, feeling safe and having an orgasm were correlates for these women. An important side note is that conflating and then averaging out research results for such a large segment such as "female" or "male" completely negates the experiences of large subgroups within those segments. So basically, take this research with a very large grain of salt.*
Because, in truth, orgasm is larger than the sum of its parts (or at least it feels like it!), I'll conclude with a poetic quote by Dr. Alfred Kinsey regarding this phenomenon:
"[Orgasm] can be likened to the crescendo, climax, and sudden stillness achieved by an orchestra of human emotions ... an explosion of tensions, and to sneezing."
I really do like sneezing.