Neuroimaging and Sexuality
Neuroimaging and Sexuality
Neuroimaging
It is a popular assumption that science most often clashes with less quantifiable areas of life such as spirituality, belief, and religion. This assumption has held for as long the “ologies” have existed. In fact, it can be said that before the systematic approach to science came about, the melding of science and religion was far worse than the separation and subsequent contention between the two that exists today.
For that reason, modern scientific research tends to reject much that is not quantifiable in the world, particularly subjects that have traditionally been associated with emotion and belief. The subjectivity of these topics has long been left to the lighter and more interpretive realms of science, mainly psychology. But with the advent of neuroimaging, scientists have seen a whole new realm open up. Since the 1970s and 80s when CAT and MRI brain scanning techniques and equipment were first invented, researchers have been able to observe with no small amount of clarity exactly were and when brain activity is occurring. Since the advent of brain scanning technology, many experiments have been done on more interpretive topics such as a study done on individuals from different faiths whom all spoke in tongues, or where brain activity was observed in individuals who professed faith in a god and compared to those who said they did not.
Though it is clearly observable that there is conclusive evidence of activity in certain areas of the brain that can be systematically tested, what does it all actually mean?
When it comes to the brain, no study is ever entirely conclusive. Even when various types of brain scanning methods and statistically accurate studies are carried out, there is always room for speculation—particularly when compared to scans of the majority of other body parts and functions which are far more conclusive and straightforward. S. M. Kosslyn of Harvard University wrote an article entitled “If neuroimaging is the question, what is the answer?”
Good question.
Furthermore, there is much speculation about neuroimaging that is based on the “chicken or egg” conundrum: Specifically, when you scan for something in the brain, are you seeing the cause or are you seeing the response? This is a clear case in the world of visualizing biology in which the actual image—often a photographic one—is not always the best evidence.
For example, when you are dealing with most of the body, the cause-effect relationship is easy to observe. The cause, usually an external force—like a plastic hammer used to test reflexes—comes in contact with the body, and the body reacts. Adversely, there are a few implicit problems when it comes to testing the brain. Initially, it is much harder to quantify neurological data in testing. Testing things such as levels of depression, the intensity of a headache, and the progression and diagnosis of myriad mental disorders makes neuroimaging much more difficult than just a question of technology or imaging errors. Not to mention, neuroimaging often times attempts to see something that is not only unquantifiable, but the question of causation is itself under suspicion. As I mentioned, when one sees an image of the brain undergoing a certain process, it is often very hard to know whether the process itself originates in the region of the brain indicating activity or if the brain is merely responding to something occurring elsewhere in the body or in the brain itself.
Neuroimaging and Sexuality: The First Studies
One such study of the brain embodies the problem of neuroimaging particularly well: The neurobiological study of sexuality.
The first studies involving MRI scans and sexual arousal were done most commonly in men, and used to determine the areas of the brain that were involved with sexual arousal. In these studies, the men were asked to watch a series of video clips—one set was of erotic video clips, another was of emotionally “neutral” material, and the last was of a humorous nature.
These studies, while mildly debatable and only relevant to the heterosexual, emotionally and physically healthy male, were fairly sound and welcomed by the scientific community. Similar studies of women were then done and showed that areas of visually-stimulated arousal were often found activated in overlapping sections of the brain with that of the male study subjects.
While potentially helpful to the pornographic industry, visually-stimulated arousal is inevitably only one small area of research within the topic of human sexuality and brain activity. Not to mention, in the studies of the women who were visually stimulated, though they showed similar regions of brain activity, the activity intensity ended up being far less than those of their male counterparts.
The Method Issue
This is but one tiny example of the complexity of human sexuality—when science attempts to face such a broad and complex issue that has been plaguing humanity for centuries without the help of science, it has to take baby steps.
Other areas within this study have raised a few eyebrows, not only because of the difficulty in quantifying such things as level of arousal and orgasm, but within the studies themselves. These studies catch the attention of the media and the public simply because of the way they have to be conducted. For one, the studies are conducted mainly and necessarily in MRI scanners, so the physical space is often problematic. Furthermore, trained scientists have to deal with less-than-scholarly questions such as the optimal environment for arousal. After all, it is often necessary to the experiment that the test subject be aroused, and in the least superficial way possible.
Every little thing counts. One study done by Willibrord Weijmar Schultz, associate professor of gynecology at University Hospital in the Netherlands flippantly mentions that in his study, “only the first couple was able to perform coitus adequately without sildenafil [Viagra]…The reason might be that they were the only participants in the real sense: involved in the research right from the beginning because of their scientific curiosity, knowledge of the body, and artistic commitment.” Not to mention they were street performers and “used to performing under pressure,” according to Schultz.
This is no small point. If researchers can’t provide the optimal environment for a given procedure, the study itself is invalid. After all, you can’t induce a mold to grow in the wrong temperatures on an inadequately prepared Petri dish. An experiment deliberately involving the arousal of an individual has to be approached from a similarly thoughtful position—no pun intended.
Other researchers have attempted to solve the issue of environment and presentation in a variety of ways. Some studies simply ask the subject to arouse themselves, while others ask the subject to bring with them a significant other to which they are generally aroused by, to sexually stimulate them. The issue with any of these methods is brought up in Schultz’s study: “All the women had a complete sexual response, but they described their orgasm as superficial.”
For the most part, studies conducted with statistical logic and concise procedures produce conclusive evidence. But Schultz’s research raises the question, does a superficial response illicit the correct brain activity?
Here’s the catch: Schultz’s study was not, in fact, conducted to even test brain activity. It was actually conducted to collect images of the pelvic region of the body, to observe the angle of the penis during intercourse. It is arguable that neuroimaging is still far too inconclusive to even deal with issues such as a superficial environment.
Deeper Considerations
Another study done by neuroanatomist Simon LeVay in which he attempts to distinguish the homosexual male brain from a heterosexual one contains within that very issue of neuroscience: Even if you can see exactly what is going on in the brain, it does not provide conclusive evidence as to when or why the change occurred. In this case, LeVey was actually examining the tissue of forty one subjects who had died from AIDS, rather than scanning the brain; the visualizations were still the same. LeVey’s experiment did show that there was conclusive evidence of a difference between the brain of a heterosexual and a homosexual male. But what can we gain by this? Yes, it is clear to see the differences—but even though the brains were different at the time of death, were they always that way?
K. R. Maravilla and C. C. Yang of the University of Washington raise a number of complications with MRI scans and sexuality in their article “Sex and the brain: The role of fMRI for assessment of sexual function and response.” Not only do they mention the high capacity for error due to head movement in the MRI and the complexity of instructions the test subject must remember and carry out, but they also raise the issue of paradigm design, or the formatting of the set of instructions given to the subject in order to produce the intended results and to account for the most possible errors. “There are multiple phases to the sexual response: desire, arousal, orgasm, and multiple physiological occurrences during each of the phases: hormonal variation, cardiovascular changes, ejaculation and pelvic floor contractions. The brain is a very complex organ and responds in multiple different ways. Trying to isolate a specific function without interference from other tasks that may be performed simultaneously by the brain is a difficult undertaking.” The design of the experiment itself is crucial in isolating the topic in question, while still leaving room for the desired variation in individual results.
Other Probable Causes of Error and Complexity in Research
The presentation of the study to the test subject is of utmost importance. Especially when it comes to a topic as broad and subjective as sexuality, the instructions must be as concise as possible. But sexuality and science don’t get along traditionally for a reason. Therefore, the normally very objective study of science has to make a few concessions and assumptions. What sort of material might arouse a man? What about a woman? Might the material itself either heighten or lessen the response? What if one of the women in a clip presented to a male test subject reminds him of his wife? Or maybe, his ex-wife?
A scientist could try to keep such mental connections out of the study by asking the men to actually be entirely physical about the arousing material they are watching—but that would incur the “pink elephant” issue: If one is told not to think of a pink elephant, what is the first thing that comes to mind? Furthermore, if the subjects allowed memories to play out while watching the videos, other areas of the mind would be activated. The complexity of brain activity of someone who is with another person or thinks of that person they have been with for a time and have an emotional connection would likely be far different than the brain activity of a man or woman simply watching a homogeneous pornographic actor or actress.
What if the female is actually a closet homosexual? If she was, is there a way to conclusively weed her out of a study intended for heterosexual females?
And what of the language of the instructions themselves? The way the material is presented has to be meticulously considered, as does atmosphere and the attitude of the doctors. As well, what about DNA testing: If there is a woman who actually bears two x chromosomes and she doesn’t herself know it, does that affect the research?
The complexities are endless.
But when the right questions are asked, it works.
One very interesting study conducted by the University of Montreal tested male subjects who were asked to watch a series of video clips intending to induce arousal. For the first section, the subjects were asked to allow themselves to become aroused by the videos. In the second section, they were asked to attempt to inhibit their responses to the material. The question they asked was imperative to success of their experiment. The study, outlined in The Journal of Neuroscience, states their initial hypothesis: “A fundamental question about the relationship between cognition and emotion concerns the neural substrate underlying emotional self-regulation.”
What the researchers found was both expected and astounding. The studies “suggest that humans have the capacity to influence the electrochemical dynamics of their brains, by voluntarily changing the nature of the mind processes unfolding in the psychological space.” This was a very successful experiment, and it is arguably because their initial hypothesis was something that could be tested within the confines of the technology—MRI brain scanning. As well, the experiment made no vast generalizations about humans and sexuality as many of the other experiments tended to do.
This study was particularly successful because the hypothesis in question was phrased and tested such that the visualization of the brain activity could actually provide the researchers with conclusive evidence that would answer their question.
You can’t work with what’s not there.
Neuroimaging encounters the same problem that all photographic media does: No matter how conclusive or sound the image is, the best one can hope for is a clear snapshot. It is very similar to a single microscope slide or x-ray image. Not only is it restricted by the technology of the x-ray or the slide itself, but the image is by nature only one snapshot in one split second of time. A cell caught in mid-mitosis, a bone fractured in a particular spot in one stage of the healing process, a mammary tumor in one stage of growth; it is comparable to when someone goes to the gas station to buy a pack of gum and the cashier asks him how his day has been going. Even if he tells her how his day was, it is merely one insignificant slice of a much, much greater whole. Especially if he was to divulge how he had just cheated on his wife and then picked his eight-year-old daughter up from school, that would not tell her why you chose to cheat on your wife, or if the daughter you had was even your wife’s child.
When it comes to sexuality, usually the problem is treated as something psychologically wrong with the person, and there is often a great deal of memory and emotion that comes into play. The good news is that by handing sexuality over to a more objective method of study, people can find a certain sense of relief. No need to blame themselves or their partners, the images simply say, “Look, here is your brain. It does not react like other brains do. For whatever reason, your body and your brain aren’t communicating correctly.” The images won’t provide snapshots of memories or traumas that may have caused the problem, but they will often take the blame off the patient, thereby allowing emotions to actually relax and a more objective method of treatment to be taken.
The problem of the image is a blessing, and the blessing of an image is its biggest problem. Because the image is an objective snapshot, it provides a slice of reality that says, “I don’t know what it means for you particularly, but this is what it’s saying about your reality objectively.”
The problem is when people ask questions of the image that an image cannot rightly answer. A picture speaks a thousand words, but when it is a brain scan, it is all scientific jargon and technical jibberish. In the study of the men versus the women being aroused by erotic images that found men being much more visually stimulated, that is as far as it can go. The image leaves much to be desired—why are women less visually oriented than men? And what is it that arouses women, if not the visual? Or in LeVay’s research of homosexual versus heterosexual brains, the snapshot we get of the brain does tell us there is a difference. But when, why, and how that difference came to be cannot be answered by the image.
The reason the last study done by the University of Montreal was successful was because they asked a question that an image could answer. Don’t get me wrong, I do not believe that science should avoid difficult topics just because they are hard to quantify or research. But sometimes images simply are not the best method of research. Just as Watson and Crick criticized their contemporaries for only researching from the chemical vantage and expecting the image to tell all of its secrets, many times MRIs will not actually answer the questions about sexuality we want to know. For example, it will be potentially more productive to study genetics
Conclusion
What caused the image to come about? What made the thing we are observing in the visualization come about? In an age where we are obsessed with proving things by pointing to a photograph and saying, “There! It’s right there for you to see,” we seem to be forgetting that we still possess mental faculties. Yes, images have their strong points and will many times provide us with the answers we want. But the question being asked is of utmost importance. If the question is asking something that an image cannot possibly answer, the method should be questioned.
Sexuality is one such study that might be better off kept in other areas of science in general, for now. Until we have a much more developed knowledge of our sexuality that comes from an understanding of the workings of the mind and of emotions, MRIs will only show us how little we know. Contrary to popular belief, images do not speak for themselves, especially when what needs to be said contains endless strings of Latin prefixes and suffixes. Until there is a solid knowledge behind the interpretation of the image, neuroimaging might better stay out of the bedroom.
Bibliography
K. R. Maravilla and C. C. Yang, “Sex and the brain: the role of fMRI for assessment of sexual function and response.” International Journal of Impotence Research 19, 25–29 (2007).
Willibrord Weijmar Schultz, Pek van Andel, Ida Sabelis, Eduard Mooyaart, “Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal” StudentBMJ (2000).
Huma Q. Rana, “The Homosexual Brain?” Serendip Online (2000) <http://serendip.brynmawr.edu/bb/neuro/neuro01/web1/Rana.html>.
Mario Beauregard, Johanne Lévesque, Pierre Bourgouin, “Neural Correlates of Conscious Self-Regulation of Emotion”. The Journal of Neuroscience 21: 1-6 (2001).
