MEG reveals preference specific increases of sexual-image-evoked responses in paedophilic sexual offenders and healthy controls.

OBJECTIVES: Paedophilic disorder is characterised by sexual attraction towards children. Classification of a counterpart as sexually attractive likely occurs rapidly, and involves both conscious and unconscious attentional and cognitive processes. Magnetoencephalography (MEG) is an imaging method especially well-suited to examine visual and attentional processes triggered by sexual images within the range of milliseconds. METHODS: We investigated brain responses to sexual images depicting adults (frequent) and children (infrequent stimulus) in seventeen paedophilic patients with a history of child sexual offending (P + CSO) and twenty healthy controls (HC) during a passive visual oddball paradigm. Event-related fields (ERF) were measured to extract the magnetic visual mismatch negativity (vMMNm), and how it relates to the processing of different classes of sexual stimuli. RESULTS: P + CSO exhibited significantly longer vMMNm latencies (100-180 ms post-stimulus) than HC. Moreover, P + CSO showed widespread increased amplitudes in response to child images starting from P3a and P3b components and lasting up to 400 ms post-stimulus presentation localised in frontal and temporal brain regions. CONCLUSIONS: This study uncovers the first MEG differences in automatic change detection between P + CSO and HC during the presentation of subliminal sexual images of adults and children, contributing towards a better understanding of the neurobiological processes of P + CSO.

Expectation of sexual images of adults and children elicits differential dorsal anterior cingulate cortex activation in pedophilic sexual offenders and healthy controls.

BACKGROUND: Pedophilic disorder is characterized by increased sexual interest towards children, with comparatively lesser interest towards adults. In real life, the behavior of subjects with pedophilic disorder is shaped by evaluative processes in response to sexually relevant cues. Therefore, brain activation during anticipation of sexually relevant cues is of potential interest. Whereas previous research demonstrated reduced activation when viewing adult (non-preferred) sexual stimuli in pedophilic sex offenders (PSOs), it is not known if anticipation of preferred versus unpreferred stimuli will elicit differential brain activation. METHODS: Two fMRI studies (1.5 and 7 Tesla) were conducted in separate samples, each with 26 subjects (13/13 PSOs/controls) to assess brain activity during expectancy of subsequent adult (non-preferred) sexual stimuli. In the second study (7 Tesla) additionally child (preferred) cues were presented. RESULTS: As predicted, expectancy of adult sexual stimuli generated smaller dorsal anterior cingulate cortex (dACC) activation in PSOs in both studies, driven by stronger activation during expectancy of adult erotic stimuli in non-pedophilic controls (HCs). In the second study, PSOs showed significantly increased activations in dACC during expectancy of child stimuli compared with expectancy of adult stimuli. This difference was significantly greater compared to the same contrast in HCs, thus demonstrating preference specificity of dACC activation. CONCLUSION: Our findings support the notion of decreased brain activation to adult cues in PSOs and preference specificity in neural response during expectancy of erotic stimuli. The localization of these cue reactivity differences in the salience network supports the interpretation that PSOs show abnormally increased preparatory activation even before relevant sexual stimuli are actually presented.

Pedophilic sex offenders are characterised by reduced GABA concentration in dorsal anterior cingulate cortex.

A pedophilic disorder is characterised by abnormal sexual urges towards prepubescent children. Child abusive behavior is frequently a result of lack of behavioral inhibition and current treatment options entail, next to suppressing unchangeable sexual orientation, measures to increase cognitive and attentional control. We tested, if in brain regions subserving attentional control of behavior and perception of salient stimuli, such inhibition deficit can be observed also on the level of inhibitory neurotransmitters. We measured GABA concentration in the dorsal anterior cingulate cortex (dACC) and in a control region, the pregenual anterior cingulate cortex (pgACC) in pedophilic sex offenders (N = 13) and matched controls (N = 13) using a 7 Tesla STEAM magnetic resonance spectroscopy (MRS). In dACC but not in the control region pedophilic sex offenders showed reduced GABA/Cr concentrations compared to healthy controls. The reduction was robust after controlling for potential influence of age and gray matter proportion within the MRS voxel (p < 0.04). Importantly, reduced GABA/Cr in patients was correlated with lower self-control measured with the Barratt Impulsiveness Scale (p = 0.028, r = -0.689). In a region related to cognitive control and salience mapping, pedophilic sex offenders showed reduction of the inhibitory neurotransmitter GABA which may be seen as a neuronal correlate of inhibition and behavioral control.