The Guide to Getting It On (81 page)

CHAPTER

39

MRIs of Sexual Arousal: Is the Brain Half Empty or Half Full?

W
hile researchers were looking for the parts of the brain that light up during sexual arousal, they actually discovered parts of the brain that were shutting down. You would think it would be the opposite, with sexual arousal causing sparks of activity arcing from ear to ear. However, it appears that in order to get into the sexual moment we need to shut down parts of our brains as well as fire up others. This would validate what women often say who take our sex survey at GuideToGettingItOn.com. When asked to describe what intercourse feels like when it’s really good, they often say that the rest of the world disappears, for example:

“When it’s really good, I feel like the world just stops and my mind goes blank and all I want to do is feel every single move, and enjoy each breath. But when its bad, I can’t stop thinking about everything other than what is really going on. My mind will be racing.”
female age 22

It’s clear that MRI or neuroimaging studies of the brain and crotch are the future of sex research. However, it’s equally fascinating to consider the limitations of brain-imaging technology when it comes to exploring sex on the brain. This chapter will give you an idea of the challenges that researchers have to deal with as they are exploring this virgin territory. Understanding the limitations of current technology is particularly important given the media’s tendency to make way too much out of findings that are tentative and have yet to be replicated and validated in other labs.

Problems with the Old (and Still Currently Used) Technology

Before sex researchers started using MRI technology to study our brains and crotches, research about sexual arousal and sexual feelings has often included tying strings around men’s penises that were attached to gauges, and sticking plastic tampons containing infrared sensors up women’s vaginas. We would then try to make educated guesses about what it meant when the strings got stretched and the sensors sensed. This was fraught with peril when you consider that a third or more of the research subjects would routinely be disqualified because their strings didn’t stretch convincingly. There were also questions about how representative a person might be who volunteers to watch porn movies in a lab with a probe stuck up her vagina—while totally sober!

Worse yet, when it came to women’s arousal, we’ve mostly been limited to measuring the changes in the blood flow in her vagina. Yet women have a clitoris that’s involved in their sexual arousal. We haven’t had a very good way of measuring what was going on inside of it other than slapping a glob of KY on the end of an ultrasound probe and pushing it up against a woman’s clitoris. So researchers have left the clitoris out of the equation when measuring female sexual arousal.

With the newer imaging technology, researchers suddenly have the capacity to not only measure what’s going on inside the entire pelvis when it’s sexually aroused, but inside the brain as well. All of this while allowing the subject to remain in relative privacy—if you assume having your genitals stimulated while attempting to lie totally still in a large metal cylinder at a university lab is private.

The Current Limitations of Neuroimaging

As exciting as the new wave will be, for now we need to be mindful that brain imaging in sexual research is still in its infancy.

A research subject’s head needs to be kept perfectly still for several minutes while the images are taken. The slightest movement results in signal changes that threaten to muck everything up. Worse yet, the part of the brain where some of our sexual arousal and orgasms are processed is located in an area of the skull that is next to a sinus cavity that the brain uses for air conditioning. By virtue of being located next to the brain’s air-conditioning shaft, even the slightest of head movements is magnified and creates even more unwanted artifacts than if it were located closer to our foreheads.

Fortunately, researchers can use higher-resolution scans with smaller voxels or volume pixels to get reliable data. Still, try to imagine a research subject having an orgasm while needing to keep his or her head perfectly still for minutes on end. Head movements during MRI studies of orgasm are one of the reasons why these studies must be reproduced in another lab before they should be considered valid, yet few studies have been replicated elsewhere.

Also, the subjects are often shown porn clips to make them feel sexually aroused while the MRIs are being done. But how do the researchers know if the subject’s brain is processing sexual arousal, or the way the porn actors’ bodies are moving (kinesthetics), or the changing frames in the video porn clips or some random thought that popped into the subject’s mind? This is a subject researchers are keenly interested in.

There’s also the question of what happens to the information when it gets inside the brain—is the information being compared to similar information that was stored in the subject’s mind years ago, or is it being treated as novel information? Is the subject’s brain processing the porn clip based on how the subject feels when he has had sex in the past, or is the turn-on strictly in the here and now, with no prior referencing?

Today’s neuroimaging technology is still crude compared to what it will be in another twenty to thirty years. Right now, the equipment doesn’t focus on the actual neurons that are firing, but on the blood that drains from that part of the brain. So let’s say researchers are focusing on what’s happening inside small parts of the brain called the amygdala, hypothalamus, and nucleus accumbens. Small as they might be, they contain oceans of neurons. Using the current generation of MRI equipment to nail down the exact neurons that are involved would be like trying to go to Mars using an XBox as your sole onboard computer.

There’s also debate about how long to measure what it is you hope you are measuring, and whether you are actually measuring what you think you are measuring. This depends on a researcher’s hypothesis about what areas of the brain are going to be activated. Because researchers use different measurements, it makes it a challenge to compare studies with each other.

The next time the media runs a big story saying that men’s brains process sexual arousal differently than women’s brains, you might wonder if the study actually measured how our brains process sexual arousal, or how they process the porn clips that the researchers were showing the subjects to get them aroused.

Think about the anticipation and erotic edge you feel when you are looking forward to having sex as a partner first arrives, as well as the sounds, smells and actual feel of your partner’s skin against yours. Does your brain respond differently to that kind of sexual arousal versus the kind when you are watching porn on a TV screen?

While the current MRI findings are exciting, thought provoking and will be unlocking many of the mind’s sexual secrets—all things in good time. For now, researchers are just beginning to break a sweat.

Note:
While reviewing this chapter, a researcher on the forefront of neuroimaging commented: “For many researchers, it’s not clear that they have specific research questions when they enter the scanner. Some of the discussion sections seem like exercises in reading tea-leaves.”

A Very Special Thanks
to
Mr. MRI
Adam Safron of Northwestern University, to Serge Stoleru of the Université Pierre et Marie Curie, and to Claire Yang and Kenneth Maravilla of the University of Washington for their very helpful article “Magnetic Resonance Imaging and the Female Sexual Response: Overview of Techniques, Results, and Future Directions” in the
Journal of Sexual Medicine.

CHAPTER

40

What’s Normal: 10,000 People Talk about Sex

S
eventeen years ago, we sent out of the first sex surveys for book that was being written called the
Guide To Getting It On
. We stapled the pages by hand and stuffed them into packets with self-addressed stamped envelopes. The responses that began arriving a few weeks later were handwritten and the pages often had coffee or tea stains on them, or that’s what we hoped they were.

Deciphering the handwriting was sometimes a slow and painful process, but people’s responses were so intimate and thoughtful that it felt wrong to not make every possible effort. Now, nearly 10,000 surveys later, the forms are filled out electronically by visitors to the website of
The Guide.
The coffee stains are gone, but the thoughtfulness and honesty remains.

As you will soon see, these surveys are different from typical sex surveys which are designed to collect data that can be scored by computers. But surveys that are designed to please a computer will never tell a person’s story. They will never leave you feeling like you have had a conversation.

These surveys were intentionally left open-ended to encourage thoughtful responses. That’s because the
Guide To Getting It On
was always meant to reflect the lives of real people.

These surveys have been a constant reminder that sex that is not simple, especially sex in relationships. They have been a reminder that “normal” incorporates a vast horizon. They have made us smile, feel awe, and occasionally drop our heads in sadness.

One of the problems with open-ended surveys is their richness doesn’t allow for the kind of number crunching that researchers need in order to make sweeping generalizations. No generalizations can be made from the surveys we collect. These surveys speak for no one other than the individuals who answered them. In fact, when we tried to find a “representative” survey to lead off with, we couldn’t. There is no single survey that represents “the women’s surveys.”

We have just published the first volume of these surveys. It has the same name as this chapter
What’s Normal, 10,000 People Talk about Sex.
This chapter is a mere drop in the bucket of the surveys we have collected. If you are interested in reading more of these surveys, please visit
The Guide’s
website at
www.Guide2Getting.com
for a link to our sex survey ebooks. We’ve priced them less than $3.00 each.

FEMALE 32

Sexual orientation:
Straight
Relationship status:
Not in a relationship

If you have had intercourse, how satisfying is it usually for you?
Very satisfying. I have orgasms 95 percent of the time.

On a scale of 1 to 10, how comfortable are you talking about what feels good sexually with a partner?
7-8. I am pretty good at saying what I like but maybe less good at saying what I don’t like, especially when I first start having sex with someone.

What are the best and worst parts of giving a male partner oral sex?
The worst part is feeling like I’m not doing a good job. The best part is just being comfortable in bed and enjoying the moment.

If you have hooked up with someone for only a night, what was the sex like?
I have had two one-night stands. The sex wasn’t that good. They were constantly moving around which wasn’t interesting or good. One guy was a terrible kisser so I wanted to wipe all the saliva from my face which was distracting.