brain on fire (123RF)

San Francisco’s North Beach in the 60’s and 70’s was all about intellectual ferment, iconic bookstores, and iconoclastic comedy clubs. I relished long weekend hours at Cafe Roma, sipping capuccino, occasional visits to Cafe Tosca to hear Pavaroti wannabes as well as  professional opera singers, belting out arias and Neapolitan songs.

There was only one fly in the ointment, a minor irritant that spoiled this intellectual Shangri-la: A narrow door, always closed, as if embarrassed by its presence amid all the boisterous high-brow culture. It was the inconspicuous entrance to a peep show.

Whenever I passed this place I couldn’t help glancing, occasionally staring, at the people stealing their way through the doorway. Many were swarthy-looking with upturned collars, often casting furtive looks before entering.

Who are these people?,” I wondered, “What’s wrong with them? Are their IQs as low as their appearance suggests?

I since learned that you don’t have to be swarthy-looking, or of low IQ, or from the lower rungs of society to love porn. Pillars of industry and academia, and even the Supreme Court do too.

 

Who are these people?

It turns out “those people” are actually most of us. In the U.S., 66% of men and 41% of women consume pornography on a monthly basis. An estimated 50% of all Internet traffic is related to sex. These percentages illustrate that pornography is no longer an issue of minority populations but a mass phenomenon that influences our society.

Interestingly, the phenomenon is not restricted to humans. A recent study found that male macaque monkeys gave up juice rewards to watch pictures of female monkeys’ bottoms.

So what’s going on in their heads?

 

Let’s start with their gray matter

The title of an aricle in JAMA Psychiatry caught my eye: Brain Structure and Functional Connectivity Associated with Pornography Consumption. Finally, I thought, some real insight into the whys and wherefores of pornography.

The study was conducted at the Max-Planck Institute in Berlin by a psychologist, Simone Kühn, and a psychiatrist, Jürgen Gallinat. They scanned the brain of 64 healthy men, average age 29, who had reported a wide range of internet pornography consumption, with an average of 4 hours per week. None of them met the criteria for Internet sex addiction according to the “Internet Sex Screening Test.”

Three types of scan were done. The first scan was morphometric, or structural brain scan, that measures the volume of the scanned region. The second used MRI to look at patterns of brain activation when the men viewed sexual or neutral images. The third was also an MRI scan, and it looked at brain activity while the men relaxed in the scanner for five minutes, a so-called resting-state scan.

 

The results of your brain on porn?

The researchers found a significant negative association between the number of hours of pornography viewing reported per week and the gray matter volume in the right caudate. This brain structure sits deep in the midbrain, and is associated with a variety of motor and behavioral functions, but the relevant one here is that it has been implicated in responses to visual beauty, and has been suggested as one of the “neural correlates of romantic love.”

This structure, as well as a structure called the putamen, showed reduced functional connectivity to the prefrontal cortex, the “executive center” of the brain. Here is an interesting aspect to the putamen’s function. It has been theorized that the “putamen plays a role, as part of a “hate circuit”, in the perception of contempt and disgust, and may be part of the motor system that’s mobilized to take action.”

 

What does it all mean?

First, what it does not mean. The fact that there is less gray matter and less neuronal activity in cerain brain circuits does not mean that these people are of any lower cognitive capacity.

Both the caudate and putamen are part of what’s called “the dorsal striatum,” which is part of the reward system. When this system is chronically stimulated, such as in drug addiction, the brain protects itself by ‘down-regulation‘, meaning less neurons, less dopamine receptors, and less activity.

This is part of the addiction phenomenon: The addicts crave to maintain their previous level of stimulation, in the face of less dopamine release and less receptors. So they take more of the drug, which in turn causes even more down-regulation, and so on and so forth.

So, you may ask, doesn’t drug addiction impair genius? Let’s consider Sigmund Freud, for a moment. His cocaine addiction did not seem to limit his brilliance. Nor did it impair Thomas Edison, not only a prodigious inventor, but a regular user of the cocaine-laced elixer of his time known as “Vin Mariani.” So the answer to the question, does drug addiction impair genius is probably a resounding NO. In fact, some geniuses have argued that their drug use actually enhanced their creative work.

So, what this study showed is, chronic exposure of the brain to highly pleasurable activities, such as recreational drugs or pornography viewing, is sooner or later associated with down-regulation of the reward system with the possibility of an addiction downward spiral.

But we are still left with the same old dilemma of ‘association does not causation imply’. Were people with porno on their brains predisposed to pornography because of a dysfunctional reward system, or did consuming pornography cause the dysfunction. The only way to settle this issue, in my opinion, is with a longitudinal study, in which non-porn consumers volunteer to subject themselves to a chronic overdose of pornography, and have appropriate measurements taken pre- and post.

 

So much for porn, what about romance?

An intriguing thought occurs to me as I close out this post. That is that romantic love and its polar opposite, hatred, actually have a neural basis, a physical seat in our brains. That seat is in the form of two unemotional (romantic or otherwise) agglomerations of neurons known as the caudate and the putamen.

And yet, this brain, comprised of 100 billion individual neurons, is capable of producing touching sentiment such as “Shall I compare thee to summer’s day” by Shakespeare or this one by the great love poet, John Donne:

“My face in thine eye, thine in mine appears,
And true plain hearts do in the faces rest;
Where can we find two better hemispheres,
Without sharp North, without declining West?
Whatever dies, was not mixed equally;
If our two loves be one; or thou and I
Love so alike that none do slacken, none can die”

Enough said!

Dov Michaeli, MD, PhD
Dov Michaeli, MD, PhD loves to write about the brain and human behavior as well as translate complicated basic science concepts into entertainment for the rest of us. He was a professor at the University of California San Francisco before leaving to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early stage biotech company developing products to improve post-surgical pain control. He is now retired and enjoys working out, following the stock market, travelling the world, and, of course, writing for TDWI.

2 COMMENTS

  1. Dear Dr. Michaeli,

    I am a 34-year old man who has not made love to a women in a very long time, but I have a very healthy appetite for adult movies. After reading about the nofap movement, I began to questioning my habit, mainly because I am not married yet, nor do I have any love interests. I read conflicting reports all of the time, and I do not understand all the biology involved. But last year I began to experiment with abstinence, and to be honest, after nine days I feel depressed, frustrated and alone. The nofap community talks about quitting forever, but many of them relapse after 3 months or so. Therefore, my question is, do the nofap people have a valid argument?

    • I think you provided the answer to your question. The nofab theory of abstinence as a “cure” to the pornography “addiction” is in the same class as the “cure” to homosexuality that certain religious people offer.

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