Mens' brains have built in sexual censor

Siân Knight Nottingham

She got legs, she
knows how to use 'em

Scientists at the University of Montreal have located the part of the brain that controls primitive sexual urges in men. The study, in the Journal of Neuroscience (2001;21:1-6), reports that when a group of 12 men were asked to do whatever necessary to avoid sexual arousal while watching erotic films, the prefrontal cortex of the brain of the subjects was activated. The men were asked to repeat the experiment while watching neutral films, and the scans failed to show the same brain activity.

In evolutionary terms, the prefrontal cortex is the most recent part of the brain to have developed. It is unique to primates but is highly developed in humans; the corresponding part of the chimpanzee brain is only 25% of the size compared with the human brain. It therefore seems that temperance*the ability to suppress sexual urges-is of particular significance in humans.

The limbic system-the emotional centre of the brain-is normally activated during sexual arousal, and the ability to effectively turn off this part of the brain has wider implications for the medical treatment of psychiatric disorders. "Disturbances of normal emotional self regulation might be a key factor in the genesis of depression and anxiety, both of which may involve a chronic inability to suppress negative emotion," the authors report in the study. They go on to say, "Given that the ability to modulate emotions is at the heart of the human experience, it is not surprising that the use of emotional self regulatory processes constitutes the core of several modern psychotherapeutic approaches."

Mario Beauregard, Johanne Levesque, and Pierre Bourgouin argue that this apparent self regulation may also be of significance in treating impulsive aggression and violence, which also arise as a consequence of defects in the regulation of emotional response. They admit, however, that there are limitations to the study: "Restriction to one arousal state makes it difficult to argue for the specificity, or generality, of the brain findings for both the sexual arousal and attempted inhibition conditions."




studentBMJ 2001;09:443-486 December ISSN 0966-6494