Neuropsychology and Law Task 5 PDF

Problem 5: LG1: Which parts of the brain are associated with paedophilia? Are all people who sexually abuse children paedophiles? Tenberg (2015): The Neurobiology and Psychology of Paedophilia: Recent Advances and Challen...

Problem 5: LG1: Which parts of the brain are associated with paedophilia? Are all people who sexually abuse children paedophiles? Tenberg (2015): The Neurobiology and Psychology of Paedophilia: Recent Advances and Challenges Sexual offenders against children can be categorized in two groups: 1) Individuals who show no sexual preference disorder, but whom, sexually abuse children a. Reasons include sexually inexperienced adolescents, mentally retarded persons, and those with antisocial personality disorders (ASPDs) b. Perpetrators within the general traumatizing family constellations, which seek surrogate partners in children c. Are usually diagnosed with various impulse-control disorders, accounting for their engaging in child sexual abuse 2) Individuals who display a sexual preference disorder, as paedophilia and/or hebephilia (sexual preference for pubescent minors a. Only 50% of all child abusers are paedophilias, and not every paedophilic individual has actually abused children Paedophilia and paedophilic disorder: a psychological perspective Classification: Defined as ongoing sexual attraction toward pre-pubertal children DSM-5: Paedophilia is de-pathologized by differentiating between the sexual preference for prepubescent children (i.e., paedophilia) and the disorder in case of additional factors such as: o Experiencing significant distress and impairment by fantasies and urges o Acting out on behavioural level, including child pornography consumption and/or committing hands-on CSA offenses. The estimated prevalence leads to questions about the diagnostic validity and reliability of paedophilia as a classification entity Table 1: Behavioural criterion was not included in the DSM-5 as a specifier, though it holds relevance for researchers and clinicians Paedophiliacs: There are paedophilic men who restrict their desire for sexual contact with children to fantasies only Other men who are at risk to commit an offense because fantasy alone does not satisfy their sexual desire. Non-Paedophilic Child Abusers: Surrogate types of sex offenders and can be diagnosed within the category of impulse- control disorder, accounting for the lack of a sexual preference for children but the committed act of CSA Is important for clinical diagnosis whether or not an erotic preference for the body scheme of children on the fantasy- level exists. High chance that information would be given voluntary by self-rereferred, self-motivated paedophilic men Less likely by those who are already involved with the legal system It is imperative to understand in what way the neurobiological conditions and sexual preference encourage the sexual behaviour Understand which neurobiological mechanisms determine and regulate sexual preference Epidemiology: Prevalence of a true paedophilic sexual preference is approximately 1% The prevalence of general fantasies is 5% among men in the general population May be between 3% to 5% in the general population In studies of men with sexual offense histories against children, these prevalences can jump from 30% for men with one offense to 61% for men with 3 or more sexual offenses against children Studies found that 57% of men recognized at least one paraphilia-associated arousal pattern as part of their fantasies 46.9% of this group used them for arousal enhancement during masturbation, and 43.7% acted out these patterns in a relationship 3.8% acted out a paedophilic preference on the behavioural level A female perpetrator was indicated by between 14 and 24% of sexually abused males and by between 6 and 14% of sexually abused females Characteristics included intellectual impairment, a high current and/or lifetime prevalence of psychiatric or personality disorders, and a high lifetime prevalence of neglect and sexual abuse. Methods for Diagnosing Paedophilia: Via clinical exploration, the context of sexual fantasies during masturbation is significant and reveals gender preferences, body scheme age of the “partner” and favoured practices Five Tanner Stages: Used for the assessment of body scheme age preference and focuses on the development of the secondary sex characteristics from 1 (prepubescent) to 5 (adult). 1) Tanner Stage 1 (Prepubescent): Displaying a complete lack of secondary sex characteristics showing no facial or pubic hair, no penile or scrotal enlargement in males no breast development or pubic hair growth in females 2) Tanner Stage 2: Corresponds to the onset of breast budding in females and testicular enlargement in males. 3) Tanner Stage 3: Depicts the breast and areola development in females, continued testicular growth and initial penile lengthening in males.  4) Tanner Stage 4: Corresponds to increased breast and areola growth, initial separation from surrounding breast tissue in females, and in males testicular volume increases, scrotum darkens, penile elongation continues. 5) Tanner Stage 5: Represents full maturity, complete breast development, and separation from surrounding breast tissue in females, full penile growth and scrotum darkness, and testicular volume in males, and full pubic hair coverage in both Paedophilia is the erotic attraction to a prepubescent body scheme corresponding to Tanner Stages 1 and 2 Measures: A. Penile Plethysmography (Phallometry): Tests a men’s level of arousal and the use of a pressure-sensitive device around’s a man’s penis which measures sexual arousal, presenting him with an array of sexually stimulating images. There’s two types: a. Circumferential: Measures intra-individual changes in penile girth through a wire band fitted around the base of the penis b. Volumetric: Uses a glass tube fitted around the penis to measure calibrated air output as a result of erection, is sensitive to small changes and useful to use when assessing partial- or non-admitters c. Sensitivity: Between 55% and 61% d. Specificities: Between 95% and 96% i. Child pornography users showed a greater phallometric response to sexual child stimuli than non-paedophilic child sexual offenders (CSO) B. Viewing Time Paradigm: measuring the length of time a participant spends looking at specific images as an indicator for sexual preference. Studies indicate a. High specificity and sensitivity to classifying sexual offenders against adolescent boys (98% control vs. 90% offender) b. Moderate sensitivity for those against boys under 14 (98 vs. 76%) c. Lower performance against adolescent/young girls (77 vs. 91%) C. Sexual Stroop Task: Measures implicit sexual associations that exert their effects automatically D. Eye-Tracking and Pupil Dilatation: May also indicate sexual preference. However can be attributable to other factors such as luminance, salience of stimuli and emotional reaction a. Eye tracking produced high sensitivity and specificity, 86.4% and 90% respectively E. Functional Magnetic Imaging (fMRI): Preference-specific BOLD pattern is evident and can be used as a diagnostic tool Co-morbidities: Paedophiles in residential or outpatient treatment: 2/3 had a lifetime history of mood or anxiety disorders 60% had a lifetime substance abuse history (51% dependent on alcohol) 60% qualified for a personality disorder diagnosis o OCD (25%), Antisocial (22.5%), Narcissistic (20%) and Avoidant (20%) Minnesota Multiphasic Personality Inventory (MMPI): Child offenders scored higher on 2 out of 3 scales for the neurotic triad (hypochondriasis and hysteria) and 3 out of 4 scales for the psychotic tetrad (paranoia, psychasthenia, schizophrenia) Neuropsychological findings: Many studies have been conducted on incarcerated child sexual offenders (CSOs) without adequately controlling for factors such as incarceration stress or specific sexual preferences, which limits the generalizability of their findings. Some studies found no significant neuropsychological differences between incarcerated adolescent offenders and controls, nor among adult male sex offenders and non-sex offenders. Other studies indicated that while some differences in neuropsychological performance were observed, they were often not specific to paedophilia. More recent studies have begun to differentiate between paedophilic and non-paedophilic offenders. Paedophilic offenders exhibited specific deficits in executive functions, particularly in information processing speed, while non-paedophilic offenders showed more generalized impairments. Some found that paedophilic offenders did not show generalized executive functioning impairments but had distinct patterns of deficits. Formerly incarcerated heterosexual paedophiles had lower scores in verbal fluency but normal performance in impulsivity and attention tests. In contrast, others reported impaired performance across various cognitive tests among convicted paedophiles. While there may be some neuropsychological deficits associated with paedophilia, these could be influenced by mental disturbances or the effects of incarceration rather than being directly linked to sexual preference. Neurobiology and neurodevelopment of paedophilia: Understood as a complex, multifactorial phenomenon influenced by genetics, stressful life events, learning processes, and structural brain integrity. Psychological Mechanisms: Included classical and operant conditioning, to explain paedophilic preferences, but these have been criticized for lack of robust methodology and evidence. o Men are more easily conditioned through exposure to sexual stimuli then women Three major neurobiological theories have emerged: A. Frontal Lobe Theory: Differences in the orbitofrontal and left and right dorsolateral prefrontal cortex, which are responsible for behaviour control  a. May explain the sexual behaviour disorders associated with paedophilia, although not the preference itself. B. Temporal Lobe Theory: Disturbances (temporal lesions and hippocampal sclerosis) in the temporal lobes can lead to hypersexuality and increased deviant sexual interests a. But it also fails to fully explain the aetiology of paedophilic preference. C. Sex Dimorphic Brain Structures Theory: Differences in brain structures influenced by testosterone exposure may affect the development of paedophilia a. But it lacks clarity on the direction of these changes. D. Fronto-Temporal Theory: Indicates that the frontal lobe is linked to committing offenses, while the temporal lobe is associated with sexual preoccupation. Paedophilia is viewed as a neurodevelopmental disorder influenced by genetic and environmental factors, with various neuropsychological and structural differences observed since childhood. However, the exact causal relationships remain unclear, and no definitive evidence supports a direct role in the development of paedophilic sexual preference Neurodevelopmental correlates of paedophilia: Prevailing perspective was that sex differences are linked solely on the exposure to testosterone in utero Sex differences in the brain are influenced by testosterone during critical developmental periods, which can lead to variations in sexual preferences. Research indicates that paedophilic men often exhibit structural and functional brain differences, with many of these differences originating in utero, childhood, and adolescence. Higher incidence of head injuries resulting in loss of consciousness before age 13 among paedophilic men o Correlates with cognitive impairments and increased rates of attention deficit-hyperactivity disorder (ADHD) and left-handedness. Organizational–Activational Hypothesis: Suggests that pubertal/adolescent androgens shape brain circuits (organization) during early development, whereas in adults androgens can only modulate the activity of these circuits (activation) Androgen receptors (ARs) can be found in several brain regions Research shows a relationship between prenatal androgen exposure and hand preference in paedophilic men with a history of sexual offending against children Neurodevelopmental markers such as sibling sex composition, parental age at birth, and fluctuating asymmetry in physical traits may also contribute to the risk of developing paedophilia. Paedophiles have a greater number of older brothers Greater paternal age at birth was related to an increased chance of homosexuality, whereas greater maternal age increased risk for paedophilia, specifically (rather than generalized paraphilia) While some studies show a link between lower intelligence and sexual delinquency, results are inconsistent, particularly when considering the use of child pornography as an indicator of paedophilic interest.  Structural (MRI) Brain Alterations in Paedophilia Most neuroimaging studies on paedophilia have found neurostructural or neurofunctional correlates of CSA, not paedophilia per se. A. Amygdala: Involved in emotional processing and has been implicated in various sexual behaviours. a. Reduced right amygdala volumes in paedophiles compared to teleiophilic controls has been confirmed b. However, the findings related to the amygdala require stricter methodologies to ensure reliability and validity. B. Orbitofrontal Cortex (disinhibition): A tumour caused impulsive sexual behaviour in a man with no previous sexual interest in children, and was associated with orbitofrontal cortex dysfunction a. When the tumour was removed, the behaviour disappeared b. However, most orbitofrontal tumours do not result in paedophilic behaviour C. Temporal Cortex (sexual preoccupation): Two cases of men with predisposition to paedophilic behaviours who has developed fronto-temporal dementia and hippocampal sclerosis presented increased sexual drive and attempts to molest children a. Showed reduced metabolism of the right temporal lobe b. However is very rare and seems to be associated to acquired hypersexual disorder and not sexual preference Voxel-Based Morphometry (VBM): MRI method which found several alterations in grey matter and white matter a) GM Volumes: a. In incarcerated exclusive heterosexual and homosexual paedophilic men with histories of sexual offending, significantly lower GM volume was found in the left parahippocampal gyrus compared to 24 teleiophiles i. When correcting for multiple comparisons b. GM reductions were found in right amygdalae, hypothalamus and substantia innominate bilaterally c. Pedosexual interest, strength of interest and sexual recidivism were associated with GM volume decreases in left insular and dorsolateral prefrontal cortices d. Preference for young children was associated with GM decreases in the orbitofrontal cortex and bilateral angular gyri b) Impaired Connectivity: a. Differences were found in the WM only i. Highlighting a bilateral connection route traveling the superior fronto-occipital fasciculus, as well as a right-sided alteration in the arcuate fasciculus. Functional (fMRI and PET) Brain alterations in paedophilia Focus on studies explaining how hetero- or homosexual teleiophilic brains process visual sexual information and regulate psychosexual and physio sexual components of sexual arousal 1) Decreased Prefrontal and Temporal Inhibition: Decreased metabolism for glucose was found in the right inferior temporal cortex and superior frontal gyrus of paedophiles a. Brain abnormality underlying decreased metabolism of temporal and frontal cortices implicated in cortical regulation of sexual arousal b. Orbitofrontal deactivation represents a dysfunction in the neural network necessary for the appropriate cognitive component of sexual arousal processing 2) Increased Attentional Brain Network Activity: Increased activity in the anterior cingulate gyrus, right prefrontal cortex, and basal ganglia 3) Decreased Activation in Regions of Autonomic Arousal: Decreased activation in hypothalamus, DLPFC, right lateral parietal, right ventrolateral, and right occipital cortices, as well as in the left insula a. Was found in paedophiles when viewing sexual stimuli compared to emotional stimuli as compared to teleiophiles b. Activation of DLPFC was inversely correlated with the score on the child abuse sub-scale of the multiphasic sexual inventory 4) Decreased Inhibition: Paedophilic participants had slower reaction times and less accurate visual target discrimination a. Which corresponded to greater activation in the “No-Go” condition for the DLPFC bilaterally, frontal eye fields, and supplementary motor areas b. In the left anterior cingulate cortex, precuneus, and angular gyrus, they showed greater activation in the “Go” condition Pattern Classification: Uses activation patterns in different brain regions in a multivariate approach rather than relying on region by region comparisons Activations seen in heterosexual and homosexual paedophiles to child stimuli are nearly indistinguishable from those in heterosexual and homosexual healthy males to adult stimuli  o Supports the assumption that paedophilia is primarily a sexual age preference Molecular Genetics and epigenetics Twin studies suggest a heritable component to sexual orientation A recent study indicates that genetic influences may also contribute to sexual interest in children, although the heritability explained was only 14.6%, which is lower than that of many psychiatric disorders. A study reported families with a high occurrence of paraphilias, including paedophilia, but found no clear Mendelian inheritance patterns. Epigenetic mechanisms seem to be at the core of sexual differentiation and serve as the interface between hormonally transmitted changes and sex chromosome related effects Conclusion: The neurodevelopmental perspective on paedophilia is significant and warrants further investigation. Previous studies have indicated that factors such as epigenetic dysregulation, physical characteristics, and brain structure/function differences may contribute to the condition. While there is some evidence of a hereditary component to paedophilia, it is relatively weak, with familial clustering observed but no clear Mendelian inheritance patterns. Epigenetics could be a valuable framework for disentangling the biological underpinnings of paedophilia. Epigenetic mechanisms can be influenced by environmental factors and may have lasting effects on brain development and function. There is absence of large-scale genetic studies, such as genome-wide association studies, in the field of paedophilia. Future studies should explore the genetic and environmental risk factors associated with paedophilia, including the impact of childhood trauma and other developmental disorders.  A multidisciplinary approach that integrates genetic, epigenetic, and environmental perspectives can be used to gain a more comprehensive understanding of paedophilia. LG2: Can paedophilia be detected by fMRI? Polisois-Keating and Joyal (2013): Functional Neuroimaging of Sexual Arousal: A Preliminary Meta-Analysis Comparing Pedophilic to Non-Pedophilic Men Paedophilic men tend to present lower IQ and neuropsychological performance, as well as structural abnormalities in grey and white matter regions Functional brain imaging studies comparing paedophilic and non-paedophilic men often report contrasts based on non- paedophilic stimuli § Patterns of brain activity can serve to identify sexual preferences o However, says little concerning the pattern of brain activation associated with sexual arousal in paedophiles AIM: Comparing brain activation in paedophiles and non-paedophiles during presentation of their preferential, sexual stimuli Method: Identified 7 studies on fMRI and PET comparing sexual arousal in paedophilic and non-paedophilic men. Based on Activation Likelihood Estimation and conducted with GingerAle 2.3 a) Three-dimensional stereotaxic coordinates of regional brain activation during the corresponding a. Condition 1: Sexual arousal condition, exposure to child stimuli for pedophiles and adult stimuli for non- pedophiles) b. Condition 2: Neutral condition b) Neuroimaging data from 58 paedophiles and 65 non-paedophiles were entered in the analysis. Only foci of activation were analysed c) Data sets (significant activations in paedophiles and non-paedophiles) were contrasted (between-group comparisons) in both directions (paedophiles > non-paedophiles and non-paedophiles > paedophiles)  Results Non-Paedophilic Controls: Sexual (adult) > non-sexual contrast revealed significant activations in (decreasing order of magnitude) A. Fusiform gyrus B. Occipital cortex C. Cerebellum D. Anterior cingulate cortex E. Amygdala F. Substantia nigra N of foci = 81 N of signidicnat clusters = 7 Table 1: Significant clusters of brain activation related with sexual arousal (sexual > non-sexual conditions) BA = Brodmann areas, NA = not applicable, MNI = Montreal Neurological Institute Paedophiliacs The corresponding contrast (sexual children > non sexual stimuli) revealed significant clusters of activation in (decreasing order of magnitude A. Occipital cortex B. Anterior cingulate cortex C. Fusiform gyrus D. Cerebellum E. Substantia nigra N of foci = 102 N of significant clusters = 10 Middle frontal gyrus, superior parietal lobule, the hippocampus, and the insula were also activated during sexual condition However, between-group comparisons failed to reveal any significant difference in either direction Discussion Although the study was based on only 123 participants, the pattern of activation did not seem to differ significantly between the groups. § However, the number of significant foci was higher in the pedophilic group This result might either reflect a) Anomalies of the brain in response to sexual arousal (undetected here because of a lack of power) b) Stronger response to sexual stimuli May be the second. That’s because: § Pedophiles typically show higher levels of sexual interest for a larger array of stimuli then men from the general population. § Additional clusters of brain activation found in the present study among the pedophilic group represented regions related to sexual arousal in the general population o On the contrary, most of the brain regions related to the cognitive/perceptual component of the sexual arousal model, were not found to be more or less activated in pedophiles Ponseti (2012): Assessment of Pedophilia Using Hemodynamic Brain Response to Sexual Stimuli DSM-IV-TR: Pedophiles experience a sustained sexual attracttion to pre-pubescent children and have eigher acted on or felt distress by this sexual urge § There seem to be neurodevelopmental and social causes for developing the illness Morphometric Magnetic Resonance Imaging (MRI): Shows reduced gray matter volume in the amygdala and interconnected areas such as the hypothalamus, ventral striatum, orbitofrontal cortex, and cerebellum § Show also reduced white matter in the superior fronto-occipital fasciculus and right arcuate fasciculus Paedophiles show reduced neural responses to adult erotic stimuli in brain areas known to be involved in sexual processing such as the amygdala, hypothalamus, and prefrontal cortex in functional MRI (fMRI) studies. However, exposure to sexual stimuli that matched their preferences, evoked preference-specific activations o Hypoactivation of the orbitofrontal cortex and hyperactivation of the dorsolateral prefrontal cortex How do you measure paedophilic preferences? Preference-specific tuning of functional activation patterns evoked by sexual stimuli could be used to assess paedophilia A study tested if brain activity in response to sexually preferred vs non-preferred stimuli predicted sexual orientation in a sample of heterosexual and homosexual men o The accuracy exceeded 85% Phallometric Tests: Measurement of minimal penis volume changes in subjects exposed ro certain stimulus-configurations § Shows that half of signle-victim offenders are pedophiles However, it’s an intrusive and not so relaiable technique AIM: Examining if an automated pattern classification of fMRI data can predict paraphilic sexual orientation Hypothesis: Maps reflecting regional differences in participants’ blood oxygen level–dependent (BOLD) response to sexual stimuli should indicate sexual orientation  Method: Participants: The study recruited 25 male participants diagnosed with pedophilia based on DSM-IV-R3 criteria, from two outpatient Sexual Medicine departments associated with the Dunkelfeld prevention project. After excluding one participant, 24 individuals remained o 11 identified as heterosexual pedophiles attracted to prepubescent girls o 13 as homosexual pedophiles attracted to prepubescent boys. o Seven participants were classified as nonexclusive pedophiles (attracted to both adults and children). Phallometric assessments confirmed the diagnosis for 11 participants, while forensic records validated others. A control group of 32 healthy male volunteers (teleiophiles) was recruited, consisting of 18 heterosexual and 14 homosexual individuals. o Both groups were matched for age and intelligence. o Exclusions were made for medical issues, sexual dysfunction, paraphilia, or history of sexual offenses. Stimuli and procedure 14 different picture categories were shown during an fMRI session, including a) Nude adults and children (whole-body frontal views, genitals only, or face only) b) Nonsexual pictures from the International Affective Picture System, categorized by high or low arousal scores. Adult sexual stimuli often showed signs of genital arousal, which helps to trigger selective neural responses based on the observer's sexual preference. A total of 490 photographs were used, with 35 images in each category. However, only trials involving whole-body frontal views or genitals entered the pattern classification analysis, resulting in 280 trials. Each image was displayed for one second with a variable interstimulus interval of 1 to 5 seconds, presented in a pseudorandom order. Participants viewed the stimuli attentively and responded manually when an oddball stimulus (a green circle) appeared, ensuring their attention was engaged. Afterward, participants rated the stimuli in terms of valence and arousal using the 9-point Self-Assessment Manikin scale. For sexual stimuli, the valence and arousal ratings were multiplied to create a combined index closely correlated with sexual attractiveness ratings. Imaging procedure and data reprocessing Participants in this study were imaged using a 3-T whole-body MRI scanner Structural T1 volumes were acquired with a 3D spoiled gradient echo sequence, followed by three fMRI runs, each consisting of 352 volumes. The BOLD signal was measured using an echo planar imaging (EPI) sequence with a 250ms repetition time, 36.8ms echo time, and a 90° flip angle.  The field of view covered the whole brain, with 38 axial slices (3 mm thick, 0.3 mm interslice gap), aligned with the anterior-posterior commissural plane. EPI images were realigned and spatially normalized applying the SPM segmentation algorithm to individual T1-weighted images for estimating nonlinear spatial normalization parameters. The EPI images were coregistered to the T1-weighted images, normalized, and then smoothed using a Gaussian kernel to account for anatomical differences across participants and allow for the application of Gaussian random field theory. Statistical analyses and subject classification A four-step process was used to classify whole-brain activity patterns in an fMRI study: I. First-Level Analysis: A general linear model was applied to fMRI data using separate regressors for eight stimulus conditions (body and genital images of boys, men, girls, and women) and movement parameters. a. The brain responses were compared for pictures of boys vs. men and girls vs. women, resulting in two t- statistic maps showing differences in brain activity for child vs. adult sexual stimuli. II. Second-Level Analysis: A flexible factorial design was built with three factors (stimulus, group, and subject) and covariates (age and intelligence) to account for variance. a. Statistical maps were calculated to compare the preferential brain responses to boys vs. men and girls vs. women between paedophiles and healthy volunteers. III. T-Map Projection: Individual brain activity patterns were compared with group difference maps, and "individual expression values" were calculated to quantify how much a participant's brain response aligned with the group- specific patterns. IV. Classification and Cross-Validation: Two classification algorithms (Fisher linear discriminant analysis and k- nearest neighbour) were used to classify participants based on their expression values. a. A leave-one-out cross-validation was performed to test classification accuracy, calculating sensitivity, specificity, and mean accuracy. b. The study also tested different thresholds to optimize classification by reducing noise and improving accuracy Results Behavioural responses Figure 1: Ratings corresponded to participant sexual preferences Main effects of stimulus type in the groups of heterosexual teleiophiles, homosexual teleiophiles, heterosexual pedophiles and homosexual pedophiles Teleiophilia: Sexual preference or attraction to adults, typically individuals who have fully reached physical and sexual maturity. Heterosexual pedophiles rated pictures of women and girls as sexually attractive, and the difference between these ratings was not significant Automatic classification Analysis of variance revealed significant differences of the individual difference maps between paedophilic and teleiophilic participants in widespread brain areas This was found in the boys vs men as well as the girls vs women contrast Figure 2: Group differences were more extended in the boy vs men than in the girls vs women contrast  Table 1: The individual brain response was characterized by 2 expression values, one for the girlswomen contrast and one for the boysmen contrast Figure 3: Displays the individual expression values based on whole-brain t-maps for all 56 participants Y-AXIS: Individual expression values of those sexually attracted to a female body (heterosexual teleiophiles and heterosexual pedophiles) differed mostly in regard to the girlswomen comparison X-AXIS: Conversely, homosexual teleiophiles and homosexual pedophiles differed predominantly with respect to the boysmen comparison  Conclusion: A pattern classification algorithm distinguished participants with pedophilia from healthy controls with a high degree of accuracy Relying solely on the spatially distributed betweengroup differences in functional brain response to sexual stimuli BOYS vs MEN: was able to discriminate within the homosexual participants those attracted to adults from those attracted to children. GIRLS vs WOMEN: The girls vs women comparison was more sensible to discriminate with regard to the heterosexual probands. In the study, they presented core sexual stimuli that triggered a highly discriminative response pattern in participants Core sexual stimuli reliably trigger preference-specific responses independent of either the sex of the participant or the stimulus Preference-Specific Brain Activity: Was found in a distributed set of brain areas, most of them known to be involved in processing sexually arousing stimuli Caudate nucleus, cingulate cortex, insula, fusiform gyrus, temporal cortex, occipital cortex, thalamus, amygdala, and cerebellum. o Activation differences in these brain areas account for the algorithm’s high classification accuracy § Only when classified by means of Fisher linear discriminant analysis. § When we restricted the calculation of the individual expression values to these brain areas, the mean classification accuracy improved from 89% to 95% The algorithm performes less optimally in cases of participants with amibiguous sexual preferences (e.g. pedophiles of the non-exclusive type) Phallometry Sensitivity: When administered to pedophiles who admit their sexual orientation, the phallometric assessment shows perfect sensitivity (100%) Specificity scores of the phallometric assessment are reported to be around 81% when pedophiles were compared with a group of healthy controls. fMRI Sensitivity: Whereas fMRI-based classification shows a maximal sensitivity of 92%. However, specificity of fMRI-based classification reaches 100%. Automatic fMRI Classification: A. Automatic classification may be more accurate than phallometry B. fMRI measures are less intrusive than phallometry and can be performed in less than 20 minutes. C. fMRI- based classification has the potential to overcome some additional limitations of phallometry D. Might be able to circumvent the problem of non-responsers in circumferential phallometry E. Might be less susceptible to manipulation because the participant has no time to elicic prepared responses to varying stimuli in a fast, event-related fMRI setting Limitations: a) Includes only individuals who admit to pedophilia a. Sensitivity of the phallometric assessment in non- admitting pedophiles is reported to be about 78% for heterosexual pedophiles and 89% for homosexual pedophiles. i. The decrease can be attributed to the ability of some men to manipulate their penile responses during the phallometric measurement. b) Small sample size