NEUROSCIENCES - The human sexual desire can be read in the brain: it results in the activation or inactivation of areas that are generally the same regardless of the sex or sexual orientation of the people concerned, according to the researcher Serge Stoléru .
This new knowledge could one day better identify sexual disorders, especially among sex offenders such as pedophiles.
All humans react in the same way. The only thing that changes is the visual stimuli that causes these reactions that do not all occur at the same time: erotic pictures of people of the opposite sex or the same sex, according to the tastes.
Real-time observation
"Even if there may be variations from one person to another, we find the same outlines" explains to Dr. AFP Dr. Stoléru, who heads within Inserm the only research group devoted to sexual desire in France.
His work has been greatly facilitated over the last fifteen years by advances in neuroimaging, with techniques such as tomography or functional MRI (magnetic resonance imaging) that provide 3D views of the activity. of the brain.
"You can not show an impulse but you can see the changes that happen in the brain at the time of the excitement," says the psychiatrist, a specialist in the brain week (March 11 to 17).
Several stimulated areas
But sexual desire is not a homogeneous entity, it involves various components such as the cognitive aspect, but also emotion and motivation and physical reactions, which are each associated with the activation of several specific regions of the body. brain.
When an erotic image is presented, it is thus the orbito-frontal cortex, above the eye, which is activated. The same goes for the imagination of erotic gestures that is associated with the activation of other regions of the frontal lobes. On the other hand, sexual emotion passes through the two tonsils, parts of the brain that allow us to feel or perceive emotions.
Beyond the areas of the brain that are animating, the researcher has also observed areas - like parts of the temporal lobes and frontal cortex - that go out under the effect of erotic stimuli and then reignite.
Zones lit or extinct
Permanently extinct, these regions maintain sexual arousal, which occurs in certain pathologies, such as temporal lobe tumors or epilepsy starting in these areas. We then witness phenomena of hyper-sexuality, such as that of spontaneous orgasms.
Conversely, when they are constantly activated, these areas cause a sharp decrease or absence of sexual desire.
Researchers on this topic are few in the world, with teams working in Germany, the United States, the Netherlands, Canada, China and South Korea, in addition to the research team. Mr. Stoléru.
Unmask pedophiles?
His team also studies sex offenders, including pedophiles. The few studies that exist suggest that their brains respond to pictures of children by activating the same areas of the brain as in a person attracted by an adult, and that these would be "automatic, unintended brain responses."
A German researcher, Jorge Ponseti (University of Kiel), who has worked on the subject even claims to be able, thanks to neuroimaging of the brain, to distinguish a person attracted by children with a risk of error of 5%, but the Dr. Stoléru remains very cautious about the possible use of this work before the courts.
"It does not mean that the person who has this activation of the brain will act, or that the person who does not have it will not act," he notes, before calling for that sexual disorders are the subject of more research.
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