Corrélats neuraux de l’attirance sexuelle pédophile

RésuméLa fréquence élevée des agressions sexuelles sur enfants et la gravité des troubles psychiatriques qu’elles contribuent à provoquer justifient de mieux étudier les mécanismes de l’attirance sexuelle pédophile, afin d’améliorer les approches thérapeutiques et préventives. Les premiers travaux en neuroimagerie fonctionnelle suggèrent que certaines régions cérébrales sont plus activées chez les patients pédophiles que chez des témoins sains en réponse à la présentation d’images non pornographiques représentant des enfants. Ces régions comprennent le cervelet, le gyrus orbitaire antérieur droit, le gyrus frontal inférieur droit, le gyrus fusiforme gauche, le cortex cingulaire antérieur gauche, et l’insula droite et gauche. Inversement, en réponse à ces images, l’activation du gyrus temporal moyen droit est plus forte chez les témoins. Pour aider à interpréter ces résultats, nous présentons un modèle neurophénoménologique de l’excitation sexuelle. Il est vraisemblable que les progrès de l’étude de la pédophilie par la neuroimagerie fonctionnelle aboutiront à des résultats pertinents sur le plan des questions et des débats judiciaires. Ces études doivent être mieux organisées grâce à la mise en place d’une plateforme consacrée à la clinique et à la recherche dans ce domaine.

The high frequency of sexual offenses against children and the severity of psychiatric disturbances that they contribute to generate warrant studying the mechanisms of pedophilic attraction to children, in order to improve therapeutic and preventive approaches. Emerging research based on functional neuroimaging techniques suggests that some brain regions are more activated in pedophilic patients than in healthy controls in response to non-pornographic images representing children. These regions include the cerebellum, the right orbital gyrus, the right inferior frontal gyrus, the left fusiform gyrus, the left anterior cingulate gyrus, the right and left insulae. By contrast, in response to these images, the activation of the right middle temporal gyrus is higher in controls. To help interpret these results, we present a neurophenomenological model of sexual arousal. This model comprises four coordinated components, i.e., cognitive, emotional, motivational, and physiological (autonomic and endocrinological). The cognitive component comprises a process of appraisal through which a stimulus is categorized as a sexual incentive and quantitatively evaluated as such. The emotional component includes the specific hedonic quality of sexual arousal, i.e., the pleasure associated with rising arousal and with the perception of specific bodily changes, such as penile tumescence. The motivational component comprises the processes that direct behavior to a sexual goal, including the perceived urge to express overt sexual behavior. The autonomic and endocrinological components include various responses (i.e., cardiovascular, respiratory, genital) leading the subject to a state of physiological readiness for sexual behavior. These four components are conceived as closely interrelated and coordinated. Finally, inhibitory processes comprise: 1) processes that are active between periods of sexual arousal and that prevent its emergence; we have suggested that this type of inhibitory control is exerted by regions of the temporal lobes where activity decreases in response to visual sexual stimuli; 2) cognitive processes that may – at least in patients with decreased sexual desire – devalue the sexual relevance of visual sexual stimuli; we have proposed that this type of control is mediated by the medial orbitofrontal cortex; and 3) processes that control the overt behavioral expression of sexual arousal, once it has begun to develop; we have proposed that the head of the right caudate nucleus participates in this function. It is likely that advances in functional neuroimaging studies of pedophilia will lead to relevant results regarding judicial issues and cases. These studies should be better organized through setting up a platform dedicated to clinical and research work in this area.