Brain processing of pictures of children in men with pedophilic disorder: A positron emission tomography study.

Although structural and functional neuroimaging techniques have recently been used to investigate the mechanisms of sexual attraction to children, a hallmark of pedophilic disorder, the differences in the processing of child sexual stimuli between men attracted to children and those attracted to adults remain unclear. Here, our purpose was to identify through positron emission tomography the brain responses of 15 male outpatients with pedophilic disorder to validated visual sexual stimuli depicting children (VSSc) and to compare them with 15 male healthy controls matched for sexual orientation (to female or male adults), age, and handedness. The patients' sample comprised both offenders and non-offenders. In response to VSSc, the between-groups analysis showed that activation in the right inferior temporal cortex [Brodmann area (BA) 20] was lower in patients than in controls. Moreover, in patients but not in controls, the presentation of VSSc induced an activation in a more caudal region of the right inferior temporal gyrus (BA 37) and in the left middle occipital gyrus (BA 19). In addition, in patients the level of activation in the caudal right inferior temporal gyrus was positively correlated with ratings of sexual arousal elicited by VSSc, whereas this correlation was negative in BA 20. These results implicate the right inferior temporal gyrus as a possible candidate area mediating sexual arousal in patients with pedophilic disorder and suggest that two of its areas play opposite, i.e., activating and inhibitory, roles.

Striatal dopamine during sensorial stimulations: a [18F]FDOPA PET study in human and cats.

Sensory stimulations of the forelimb in cats are known to increase dopamine release in the ipsilateral striatum and to decrease it in the homologous contralateral structure. Using positron emission tomography in both humans and cats, the present study shows that such sensory stimulations greatly reduce [(18)F]FDOPA accumulation ipsilateral to the stimulation (by 40.4% and 26.4% in the human caudate and putamen, respectively, and by 33.3% in the cat striatum). This decrease in striatal [(18)F]FDOPA uptake suggests a reduced DA storage resulting from the increased amine release. No change was observed in the contralateral striatum in neither human or cat suggesting, in contrast, that [(18)F]FDOPA accumulation is not facilitated by decreased DA release. These results support the hypothesis that sensory stimulations activate a non-synaptic mode of dopamine release.

Brain processing of visual sexual stimuli in treated and untreated hypogonadal patients.

OBJECTIVE: Although various brain regions have been shown to respond to the presentation of visual sexual stimuli (VSS), whether these regions are specifically mediating sexual arousal or whether they mediate general emotional or motivational arousal is unknown. To clarify this issue, our purpose was to map the regions where the response to VSS was related to plasma testosterone. Specific objectives were (i) to identify regions that respond differentially to VSS in untreated hypogonadal patients compared with healthy controls and (ii) to identify in hypogonadal patients the regions that respond differentially to VSS as a function of therapeutically induced increased testosterone levels. METHOD: In nine male hypogonadal patients, in the same patients under treatment, and in eight healthy males, we used Positron Emission Tomography to investigate responses of regional cerebral blood flow to VSS. Statistical Parametric Mapping was used to locate regions that demonstrated a differential response. RESULTS: Regions responding differentially both in untreated patients compared with controls and in untreated patients compared with themselves under treatment were the right orbitofrontal cortex, insula and claustrum, where the activation was higher in controls than in untreated patients and where activation increased under treatment, and the left inferior frontal gyrus, that demonstrated a deactivation only in controls and in patients under treatment. That these responses appear to depend on testosterone indicates that these regions mediate sexual arousal and not only a process of general emotional or motivational arousal.

Brain processing of visual sexual stimuli in men with hypoactive sexual desire disorder.

Although hypoactive sexual desire disorder (HSDD) is a common condition and has long been hypothesized to result from malfunctions of the cerebral control mechanisms that adjust the level of sexual motivation, very little is known about the pathophysiology of this disorder. The primary objective was to identify in patients with HSDD brain regions where functional perturbations disrupt the regulation of sexual motivation. We used positron emission tomography to compare seven male patients with HSDD with eight healthy men on their regional cerebral blood flow responses to visual sexual stimuli (VSS) of graded intensity. Statistical Parametric Mapping was used to locate brain regions that demonstrated a differential activation (or deactivation) across the groups. Whereas in control subjects the medial orbitofrontal cortex showed a deactivation in response to VSS, in HSDD patients there was an abnormally maintained activity of this region, which has been implicated in the inhibitory control of motivated behavior. By contrast, the reverse pattern-activation in control subjects, deactivation or unchanged activity in patients-was found in the secondary somatosensory cortex and inferior parietal lobules, regions mediating emotional and motor imagery processes, as well as in those areas of the anterior cingulate gyrus and of the frontal lobes that are involved in premotor processes.