Beyond the veil of duality-topographic reorganization model of meditation.

Meditation can exert a profound impact on our mental life, with proficient practitioners often reporting an experience free of boundaries between a separate self and the environment, suggesting an explicit experience of "nondual awareness." What are the neural correlates of such experiences and how do they relate to the idea of nondual awareness itself? In order to unravel the effects that meditation has on the brain's spatial topography, we review functional magnetic resonance imaging brain findings from studies specific to an array of meditation types and meditator experience levels. We also review findings from studies that directly probe the interaction between meditation and the experience of the self. The main results are (i) decreased posterior default mode network (DMN) activity, (ii) increased central executive network (CEN) activity, (iii) decreased connectivity within posterior DMN as well as between posterior and anterior DMN, (iv) increased connectivity within the anterior DMN and CEN, and (v) significantly impacted connectivity between the DMN and CEN (likely a nonlinear phenomenon). Together, these suggest a profound organizational shift of the brain's spatial topography in advanced meditators-we therefore propose a topographic reorganization model of meditation (TRoM). One core component of the TRoM is that the topographic reorganization of DMN and CEN is related to a decrease in the mental-self-processing along with a synchronization with the more nondual layers of self-processing, notably interoceptive and exteroceptive-self-processing. This reorganization of the functionality of both brain and self-processing can result in the explicit experience of nondual awareness. In conclusion, this review provides insight into the profound neural effects of advanced meditation and proposes a result-driven unifying model (TRoM) aimed at identifying the inextricably tied objective (neural) and subjective (experiential) effects of meditation.

Dissociation and emotion regulation strategies: A meta-analytic review.

OBJECTIVE: Clinical and neurobiological models posited that dissociative mechanisms might affect processes involved in emotional generation and regulation. However, there is a lack of a comprehensive theoretical framework that systematically includes dissociation within emotional functioning. METHODS: The current study aims at conducting a meta-analytic review on the relationship between dissociation and emotion regulation in order to empirically estimate to what extent dissociation is related to emotion regulation processes. The meta-analysis was based on r coefficient as effect size measure, using a random-effect approach. RESULTS: The meta-analysis included 57 independent studies for a total of 11596 individuals. Findings showed an overall moderate relationship between dissociation and emotion regulation (rw = .32; p < .05). The association between dissociation and emotion regulation was the same among clinical samples than non-clinical ones. Furthermore, dissociation showed moderate to large relationships with maladaptive domains of emotion regulation, namely disengagement (rw = 0.34; p < .01) (i.e., behavioral avoidance, experiential avoidance, thought and emotional suppression) and aversive cognitive perseveration (rw = 0.38; p < .001) (i.e., rumination, worry and nonacceptance). The analysis did not find significant relationship between dissociation and adaptive domain of emotional regulation (i.e., problem solving, mindfulness). CONCLUSION: Dissociation in the context of emotion regulation might be viewed as a basic neuro-mental mechanism that automatically contribute to the over-modulation of emotional states through avoidance reactions from internal and external reality. Future longitudinal studies are needed to clarify the causal relationships between dissociation and emotion regulation.

Prestimulus dynamics blend with the stimulus in neural variability quenching.

Neural responses to the same stimulus show significant variability over trials, with this variability typically reduced (quenched) after a stimulus is presented. This trial-to-trial variability (TTV) has been much studied, however how this neural variability quenching is influenced by the ongoing dynamics of the prestimulus period is unknown. Utilizing a human intracranial stereo-electroencephalography (sEEG) data set, we investigate how prestimulus dynamics, as operationalized by standard deviation (SD), shapes poststimulus activity through trial-to-trial variability (TTV). We first observed greater poststimulus variability quenching in those real trials exhibiting high prestimulus variability as observed in all frequency bands. Next, we found that the relative effect of the stimulus was higher in the later (300-600ms) than the earlier (0-300ms) poststimulus period. Lastly, we replicate our findings in a separate EEG dataset and extend them by finding that trials with high prestimulus variability in the theta and alpha bands had faster reaction times. Together, our results demonstrate that stimulus-related activity, including its variability, is a blend of two factors: 1) the effects of the external stimulus itself, and 2) the effects of the ongoing dynamics spilling over from the prestimulus period - the state at stimulus onset - with the second dwarfing the influence of the first.

All roads lead to the motor cortex: psychomotor mechanisms and their biochemical modulation in psychiatric disorders.

Psychomotor abnormalities have been abundantly observed in psychiatric disorders like major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SCH). Although early psychopathological descriptions highlighted the truly psychomotor nature of these abnormalities, more recent investigations conceive them rather in purely motor terms. This has led to an emphasis of dopamine-based abnormalities in subcortical-cortical circuits including substantia nigra, basal ganglia, thalamus, and motor cortex. Following recent findings in MDD, BD, and SCH, we suggest a concept of psychomotor symptoms in the literal sense of the term by highlighting three specifically psychomotor (rather than motor) mechanisms including their biochemical modulation. These include: (i) modulation of dopamine- and substantia nigra-based subcortical-cortical motor circuit by primarily non-motor subcortical raphe nucleus and serotonin via basal ganglia and thalamus (as well as by other neurotransmitters like glutamate and GABA); (ii) modulation of motor cortex and motor network by non-motor cortical networks like default-mode network and sensory networks; (iii) global activity in cortex may also shape regional distribution of neural activity in motor cortex. We demonstrate that these three psychomotor mechanisms and their underlying biochemical modulation are operative in both healthy subjects as well as in MDD, BD, and SCH subjects; the only difference consists in the fact that these mechanisms are abnormally balanced and thus manifest in extreme values in psychiatric disorders. We conclude that psychomotor mechanisms operate in a dimensional and cross-nosological way as their degrees of expression are related to levels of psychomotor activity (across different disorders) rather than to the diagnostic categories themselves. Psychomotor mechanisms and their biochemical modulation can be considered paradigmatic examples of a dimensional approach as suggested in RDoC and the recently introduced spatiotemporal psychopathology.

A Neural Signature of Parkinsonism in Patients With Schizophrenia Spectrum Disorders: A Multimodal MRI Study Using Parallel ICA.

Motor abnormalities in schizophrenia spectrum disorders (SSD) have increasingly attracted scientific interest in the past years. However, the neural mechanisms underlying parkinsonism in SSD are unclear. The present multimodal magnetic resonance imaging (MRI) study examined SSD patients with and without parkinsonism, as defined by a Simpson and Angus Scale (SAS) total score of ≥4 (SAS group, n = 22) or <4 (non-SAS group, n = 22). Parallel independent component analysis (p-ICA) was used to examine the covarying components among gray matter volume maps computed from structural MRI (sMRI) and fractional amplitude of low-frequency fluctuations (fALFF) maps computed from resting-state functional MRI (rs-fMRI) patient data. We found a significant correlation (P = .020, false discovery rate [FDR] corrected) between an sMRI component and an rs-fMRI component, which also significantly differed between the SAS and non-SAS group (P = .042, z = -2.04). The rs-fMRI component comprised the cortical sensorimotor network, and the sMRI component included predominantly a frontothalamic/cerebellar network. Across the patient sample, correlations adjusted for the Positive and Negative Syndrome Scale (PANSS) total scores showed a significant relationship between tremor score and loadings of the cortical sensorimotor network, as well as between glabella-salivation score, frontothalamic/cerebellar and cortical sensorimotor network loadings. These data provide novel insights into neural mechanisms of parkinsonism in SSD. Aberrant bottom-up modulation of cortical motor regions may account for these specific motor symptoms, at least in patients with SSD.

Real-time fMRI neurofeedback reduces auditory hallucinations and modulates resting state connectivity of involved brain regions: Part 2: Default mode network -preliminary evidence.

Auditory hallucinations (AHs) are one of the most distressing symptoms of schizophrenia (SZ) and are often resistant to medication. Imaging studies of individuals with SZ show hyperactivation of the default mode network (DMN) and the superior temporal gyrus (STG). Studies in SZ show DMN hyperconnectivity and reduced anticorrelation between DMN and the central executive network (CEN). DMN hyperconnectivity has been associated with positive symptoms such as AHs while reduced DMN anticorrelations with cognitive impairment. Using real-time fMRI neurofeedback (rt-fMRI-NFB) we trained SZ patients to modulate DMN and CEN networks. Meditation is effective in reducing AHs in SZ and to modulate brain network integration and increase DMN anticorrelations. Consequently, patients were provided with meditation strategies to enhance their abilities to modulate DMN/CEN. Results show a reduction of DMN hyperconnectivity and increase in DMNCEN anticorrelation. Furthermore, the change in individual DMN connectivity significantly correlated with reductions in AHs. This is the first time that meditation enhanced through rt-fMRI-NFB is used to reduce AHs in SZ. Moreover, it provides the first empirical evidence for a direct causal relation between meditation enhanced rt-fMRI-NFB modulation of DMNCEN activity and post-intervention modulation of resting state networks ensuing in reductions in frequency and severity of AHs.

Intrinsic brain activity of subcortical-cortical sensorimotor system and psychomotor alterations in schizophrenia and bipolar disorder: A preliminary study.

OBJECTIVE: Alterations in psychomotor dimension cut across different psychiatric disorders, such as schizophrenia (SCZ) and bipolar disorder (BD). This preliminary study aimed to investigate the organization of intrinsic brain activity in the subcortical-cortical sensorimotor system in SCZ (and BD) as characterized according to psychomotor dimension. METHOD: In this resting-state functional magnetic resonance imaging (fMRI) study, functional connectivity (FC) between thalamus and sensorimotor network (SMN), along with FC from substantia nigra (SN) and raphe nuclei (RN) to basal ganglia (BG) and thalamic regions, were investigated by using an a-priori-driven and dimensional approach. This was done in two datasets: SCZ patients showing inhibited psychomotricity (n = 18) vs. controls (n = 19); SCZ patients showing excited psychomotricity (n = 20) vs. controls (n = 108). Data from a third dataset of BD in inhibited depressive or manic phases (reflecting inhibited or excited psychomotricity) were used as control. RESULTS: SCZ patients suffering from psychomotor inhibition showed decreased thalamus-SMN FC toward around-zero values paralleled by a concomitant reduction of SN-BG/thalamus FC and RN-BG/thalamus FC (as BD patients in inhibited depression). By contrast, SCZ patients suffering from psychomotor excitation exhibited increased thalamus-SMN FC toward positive values paralleled by a concomitant reduction of RN-BG/thalamus FC (as BD patients in mania). CONCLUSIONS: These findings suggest that patients exhibiting low or high levels of psychomotor activity show distinct patterns of thalamus-SMN coupling, which could be traced to specific deficit in SN- or RN-related connectivity. Notably, this was independent from the diagnosis of SCZ or BD, supporting an RDoC-like dimensional approach to psychomotricity.

The self in art therapy - Brain-based assessment of the drawing process.

Art therapy plays important role in classical psychological assessment as it allows expressing the subject's sense of self. However, its effectiveness and validity could be impeded by lack of relationship to the patients' neuronal changes in their brain. The aim of our theoretical-empirical paper is to propose a novel brain-based quantitative objective measurement of the self and how it shapes the drawing process. We discuss recent data that how the autocorrelation window (ACW) is related to the temporal continuity of self in current neuroscience and further develop a method to use ACW to measure the temporal continuity of the drawing process, probing it in two case studies. As expected, the schizophrenic subject shows lower ACW values compared to the healthy subject and reflects the well-known deficit in the temporal continuity of the self in schizophrenia. We concluded that ACW and eventually other measures of the brain's spatiotemporal structure might be able to serve as objective markers of the self in the drawing process. As our approach connects brain, self, and drawing process, it provides the theoretical basis for the future development of a brain-based assessment of the self in the drawing process and art therapy.

Abnormal Functional Relationship of Sensorimotor Network With Neurotransmitter-Related Nuclei via Subcortical-Cortical Loops in Manic and Depressive Phases of Bipolar Disorder.

OBJECTIVE: Manic and depressive phases of bipolar disorder (BD) show opposite psychomotor symptoms. Neuronally, these may depend on altered relationships between sensorimotor network (SMN) and subcortical structures. The study aimed to investigate the functional relationships of SMN with substantia nigra (SN) and raphe nuclei (RN) via subcortical-cortical loops, and their alteration in bipolar mania and depression, as characterized by psychomotor excitation and inhibition. METHOD: In this resting-state functional magnetic resonance imaging (fMRI) study on healthy (n = 67) and BD patients (n = 100), (1) functional connectivity (FC) between thalamus and SMN was calculated and correlated with FC from SN or RN to basal ganglia (BG)/thalamus in healthy; (2) using an a-priori-driven approach, thalamus-SMN FC, SN-BG/thalamus FC, and RN-BG/thalamus FC were compared between healthy and BD, focusing on manic (n = 34) and inhibited depressed (n = 21) patients. RESULTS: (1) In healthy, the thalamus-SMN FC showed a quadratic correlation with SN-BG/thalamus FC and a linear negative correlation with RN-BG/thalamus FC. Accordingly, the SN-related FC appears to enable the thalamus-SMN coupling, while the RN-related FC affects it favoring anti-correlation. (2) In BD, mania showed an increase in thalamus-SMN FC toward positive values (ie, thalamus-SMN abnormal coupling) paralleled by reduction of RN-BG/thalamus FC. By contrast, inhibited depression showed a decrease in thalamus-SMN FC toward around-zero values (ie, thalamus-SMN disconnection) paralleled by reduction of SN-BG/thalamus FC (and RN-BG/thalamus FC). The results were replicated in independent HC and BD datasets. CONCLUSIONS: These findings suggest an abnormal relationship of SMN with neurotransmitters-related areas via subcortical-cortical loops in mania and inhibited depression, finally resulting in psychomotor alterations.

Multimodal Magnetic Resonance Imaging Data Fusion Reveals Distinct Patterns of Abnormal Brain Structure and Function in Catatonia.

Catatonia is a nosologically unspecific syndrome, which subsumes a plethora of mostly complex affective, motor, and behavioral phenomena. Although catatonia frequently occurs in schizophrenia spectrum disorders (SSD), specific patterns of abnormal brain structure and function underlying catatonia are unclear at present. Here, we used a multivariate data fusion technique for multimodal magnetic resonance imaging (MRI) data to investigate patterns of aberrant intrinsic neural activity (INA) and gray matter volume (GMV) in SSD patients with and without catatonia. Resting-state functional MRI and structural MRI data were collected from 87 right-handed SSD patients. Catatonic symptoms were examined on the Northoff Catatonia Rating Scale (NCRS). A multivariate analysis approach was used to examine co-altered patterns of INA and GMV. Following a categorical approach, we found predominantly frontothalamic and corticostriatal abnormalities in SSD patients with catatonia (NCRS total score ≥ 3; n = 24) when compared to SSD patients without catatonia (NCRS total score = 0; n = 22) matched for age, gender, education, and medication. Corticostriatal network was associated with NCRS affective scores. Following a dimensional approach, 33 SSD patients with catatonia according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision were identified. NCRS behavioral scores were associated with a joint structural and functional system that predominantly included cerebellar and prefrontal/cortical motor regions. NCRS affective scores were associated with frontoparietal INA. This study provides novel neuromechanistic insights into catatonia in SSD suggesting co-altered structure/function-interactions in neural systems subserving coordinated visuospatial functions and motor behavior.

Abnormal Resting-State Connectivity in a Substantia Nigra-Related Striato-Thalamo-Cortical Network in a Large Sample of First-Episode Drug-Naïve Patients With Schizophrenia.

Objective: The dopamine hypothesis is one of the most influential theories of the neurobiological background of schizophrenia (SCZ). However, direct evidence for abnormal dopamine-related subcortical-cortical circuitry disconnectivity is still lacking. The aim of this study was therefore to test dopamine-related substantia nigra (SN)-based striato-thalamo-cortical resting-state functional connectivity (FC) in SCZ. Method: Based on our a priori hypothesis, we analyzed a large sample resting-state functional magnetic resonance imaging (fMRI) dataset from first-episode drug-naïve SCZ patients (n = 112) and healthy controls (n = 82) using the SN as the seed region for an investigation of striato-thalamo-cortical FC. This was done in the standard band of slow frequency oscillations and then in its subfrequency bands (Slow4 and Slow5). Results: The analysis showed in SCZ: (1) reciprocal functional hypo-connectivity between SN and striatum, with differential patterns for Slow5 and Slow4; (2) functional hypo-connectivity between striatum and thalamus, as well as functional hyper-connectivity between thalamus and sensorimotor cortical areas, specifically in Slow4; (3) correlation of thalamo-sensorimotor functional hyper-connectivity with psychopathological symptoms. Conclusions: We demonstrate abnormal dopamine-related SN-based striato-thalamo-cortical FC in slow frequency oscillations in first-episode drug-naive SCZ. This suggests that altered dopaminergic function in the SN leads to abnormal neuronal synchronization (as indexed by FC) within subcortical-cortical circuitry, complementing the dopamine hypothesis in SCZ on the regional level of resting-state activity.

Thalamo-Sensorimotor Functional Connectivity Correlates with World Ranking of Olympic, Elite, and High Performance Athletes.

Brain plasticity studies have shown functional reorganization in participants with outstanding motor expertise. Little is known about neural plasticity associated with exceptionally long motor training or of its predictive value for motor performance excellence. The present study utilised resting-state functional magnetic resonance imaging (rs-fMRI) in a unique sample of world-class athletes: Olympic, elite, and internationally ranked swimmers (n = 30). Their world ranking ranged from 1st to 250th: each had prepared for participation in the Olympic Games. Combining rs-fMRI graph-theoretical and seed-based functional connectivity analyses, it was discovered that the thalamus has its strongest connections with the sensorimotor network in elite swimmers with the highest world rankings (career best rank: 1-35). Strikingly, thalamo-sensorimotor functional connections were highly correlated with the swimmers' motor performance excellence, that is, accounting for 41% of the individual variance in best world ranking. Our findings shed light on neural correlates of long-term athletic performance involving thalamo-sensorimotor functional circuits.

Intertrial Variability in the Premotor Cortex Accounts for Individual Differences in Peripersonal Space.

We live in a dynamic environment, constantly confronted with approaching objects that we may either avoid or be forced to address. A multisensory and sensorimotor interface, the peripersonal space (PPS), mediates every physical interaction between our body and the environment. Behavioral investigations show high variability in the extension of PPS across individuals, but there is a lack of evidence on the neural underpinnings of these large individual differences. Here, we used approaching auditory stimuli and fMRI to capture the individual boundary of PPS and examine its neural underpinnings. Precisely, we tested the hypothesis that intertrial variability (ITV) in brain regions coding PPS predicts individual differences of its boundary at the behavioral level. Selectively in the premotor cortex, we found that ITV, rather than trial-averaged amplitude, of BOLD responses to far rather than near dynamic stimuli predicts the individual extension of PPS. Our results provide the first empirical support for the relevance of ITV of brain responses for individual differences in human behavior. SIGNIFICANCE STATEMENT: Peripersonal space (PPS) is a multisensory and sensorimotor interface mediating every physical interaction between the body and the environment. A major characteristic of the boundary of PPS in humans is the extremely high variability of its location across individuals. We show that interindividual differences in the extension of the PPS are predicted by variability of BOLD responses in the premotor cortex to far stimuli approaching our body. Our results provide the first empirical support to the relevance of variability of evoked responses for human behavior and its variance across individuals.

Increase in glutamate/glutamine concentration in the medial prefrontal cortex during mental imagery: A combined functional mrs and fMRI study.

Recent functional magnetic resonance spectroscopy (fMRS) studies have shown changes in glutamate/glutamine (Glx) concentrations between resting-state and active-task conditions. However, the types of task used have been limited to sensory paradigms, and the regions from which Glx concentrations have been measured limited to sensory ones. This leaves open the question as to whether the same effect can be seen in higher-order brain regions during cognitive tasks. Cortical midline structures, especially the medial prefrontal cortex (MPFC), have been suggested to be involved in various such cognitive tasks. We, therefore set out to use fMRS to investigate the dynamics of Glx concentrations in the MPFC between resting-state and mental imagery task conditions. The auditory cortex was used as a control region. In addition, functional magnetic resonance imaging was used to explore task-related neural activity changes. The mental imagery task consisted of imagining swimming and was applied to a large sample of healthy participants (n = 46). The participants were all competitive swimmers, ensuring proficiency in mental-swimming. Glx concentrations in the MPFC increased during the imagery task, as compared to resting-state periods preceding and following the task. These increases mirror BOLD activity changes in the same region during the task. No changes in either Glx concentrations or BOLD activity were seen in the auditory cortex. These findings contribute to our understanding of the biochemical basis of generating or manipulating mental representations and the MPFC's role in this.

The self and its resting state in consciousness: an investigation of the vegetative state.

Recent studies have demonstrated resting-state abnormalities in midline regions in vegetative state/unresponsive wakefulness syndrome and minimally conscious state patients. However, the functional implications of these resting-state abnormalities remain unclear. Recent findings in healthy subjects have revealed a close overlap between the neural substrate of self-referential processing and the resting-state activity in cortical midline regions. As such, we investigated task-related neural activity during active self-referential processing and various measures of resting-state activity in 11 patients with disorders of consciousness (DOC) and 12 healthy control subjects. Overall, the results revealed that DOC patients exhibited task-specific signal changes in anterior and posterior midline regions, including the perigenual anterior cingulate cortex (PACC) and posterior cingulate cortex (PCC). However, the degree of signal change was significantly lower in DOC patients compared with that in healthy subjects. Moreover, reduced signal differentiation in the PACC predicted the degree of consciousness in DOC patients. Importantly, the same midline regions (PACC and PCC) in DOC patients also exhibited severe abnormalities in the measures of resting-state activity, that is functional connectivity and the amplitude of low-frequency fluctuations. Taken together, our results provide the first evidence of neural abnormalities in both the self-referential processing and the resting state in midline regions in DOC patients. This novel finding has important implications for clinical utility and general understanding of the relationship between the self, the resting state, and consciousness.

Dissociation between anterior and posterior cortical regions during self-specificity and familiarity: a combined fMRI-meta-analytic study.

The familiarity to the subject of any potential stimuli presents one of the major difficulties for the investigation of the self; the separation of effects resulting from familiarity from self-effects being extremely problematic. The aim of this study was thus to investigate the neural distinction between self and familiarity by combining two sets of fMRI data with a meta-analysis. In the first fMRI experiment, regions responding to self/familiarity were investigated using the subject's own name and names of familiar others. These effects were confirmed and extended in a second fMRI experiment using the subject's own name and a stranger's name, as spoken by familiar and unfamiliar voices. Finally, a meta-analysis of self- and familiarity-related studies was conducted. Neural activity in the anterior brain regions, such as the anterior cingulate (ACC) and anterior insula (AI), was found to be specific for self-specific stimuli. In contrast, posterior brain regions, such as the posterior cingulate, were activated by familiar stimuli. Finally, the distinction between anterior and posterior regions for self and familiarity was confirmed by meta-analytic data. This study demonstrates a clear anterior-posterior cortical partition between self-specificity and familiarity.

High resolution fMRI of subcortical regions during visual erotic stimulation at 7 T.

OBJECT: Involvement of distinct subcortical structures during sexual arousal was shown in animals and functional imaging studies gave coarse evidence for a similar organisation in humans. In contrast to previous imaging studies at lower field strengths, we tried to investigate activation in distinguishable subcortical structures at high spatial resolution during a short stimulating paradigm to further account for potential effects of attenuation or adaptation. MATERIALS AND METHODS: Seven healthy subjects were investigated using functional magnetic resonance imaging (fMRI) on a 7 T scanner. High resolution EPI images of 1.4 x 1.4 mm2 inplane resolution were acquired in a single functional session of 13.6 minutes. During the session erotic and non-erotic pictures were presented in an event-related design. RESULTS: In the unsmoothed data with preserved high spatial resolution significant effects were detected in relevant structures, including anterior caudate and mediodorsal thalamus. These effects were restricted to subcortical target structures and their anatomical boundaries. CONCLUSION: This study demonstrates that fMRI at high fields provides an ideal tool to investigate functional anatomy of subcortical structures. Due to an increased signal-to-noise ratio, functional scans of short duration can be acquired at high resolution without the need for further spatial smoothing.

Brain pathology in pedophilic offenders: evidence of volume reduction in the right amygdala and related diencephalic structures.

CONTEXT: Pedophilic crime causes considerable public concern, but no causative factor of pedophilia has yet been pinpointed. In the past, etiological theories postulated a major impact of the environment, but recent studies increasingly emphasize the role of neurobiological factors, as well. However, the role of alterations in brain structures that are crucial in the development of sexual behavior has not yet been systematically studied in pedophilic subjects. OBJECTIVE: To examine whether pedophilic perpetrators show structural neuronal deficits in brain regions that are critical for sexual behavior and how these deficits relate to criminological characteristics. DESIGN: Amygdalar volume and gray matter of related structures that are critical for sexual development were compared in 15 nonviolent male pedophilic perpetrators (forensic inpatients) and 15 controls using complementary morphometric analyses (voxel-based morphometry and volumetry). Psychosocial adjustment and sexual offenses were also assessed. RESULTS: Pedophilic perpetrators showed a significant decrease of right amygdalar volume, compared with healthy controls (P = .001). We observed reduced gray matter in the right amygdala, hypothalamus (bilaterally), septal regions, substantia innominata, and bed nucleus of the striae terminalis. In 8 of the 15 perpetrators, enlargement of the anterior temporal horn of the right lateral ventricle that adjoins the amygdala could be recognized by routine qualitative clinical assessment. Smaller right amygdalar volumes were correlated with the propensity to commit uniform pedophilic sexual offenses exclusively (P = .006) but not with age (P = .89). CONCLUSIONS: Pedophilic perpetrators show structural impairments of brain regions critical for sexual development. These impairments are not related to age, and their extent predicts how focused the scope of sexual offenses is on uniform pedophilic activity. Subtle defects of the right amygdala and closely related structures might be implicated in the pathogenesis of pedophilia and might possibly reflect developmental disturbances or environmental insults at critical periods.

Pedophilia is linked to reduced activation in hypothalamus and lateral prefrontal cortex during visual erotic stimulation.

BACKGROUND: Although pedophilia is of high public concern, little is known about underlying neural mechanisms. Although pedophilic patients are sexually attracted to prepubescent children, they show no sexual interest toward adults. This study aimed to investigate the neural correlates of deficits of sexual and emotional arousal in pedophiles. METHODS: Thirteen pedophilic patients and 14 healthy control subjects were tested for differential neural activity during visual stimulation with emotional and erotic pictures with functional magnetic resonance imaging. RESULTS: Regions showing differential activations during the erotic condition comprised the hypothalamus, the periaqueductal gray, and dorsolateral prefrontal cortex, the latter correlating with a clinical measure. Alterations of emotional processing concerned the amygdala-hippocampus and dorsomedial prefrontal cortex. CONCLUSIONS: Hypothesized regions relevant for processing of erotic stimuli in healthy individuals showed reduced activations during visual erotic stimulation in pedophilic patients. This suggests an impaired recruitment of key structures that might contribute to an altered sexual interest of these patients toward adults.