Mediation of the relationship between callous-unemotional traits and proactive aggression by amygdala response to fear among children with conduct problems

Intranasal oxytocin modulates brain activity during emotional processing in children with treatment resistant conduct problems

One of the most highly replicated neural correlates of Conduct Problems (CP) is amygdala hypoactivity to another person's fear. We recently reported that this correlate was only observed in boys with persistent CP (i.e. antisocial behaviour that persisted following a gold-standard psychological intervention), suggesting that amygdala hypoactivity to fear could be an important neural signature for treatment-resistant CP, and a putative target for future treatments. Potential treatment candidates include the oxytocin system, as this has been reported to modulate amygdala activity and social behaviour across species. Further, in adults with antisocial personality disorder, intranasal oxytocin improved facial emotion recognition for fearful and happy faces. However, to-date, no-one has studied whether intranasal oxytocin can normalise neural processing differences in children with CP. Twenty boys (mean age 9.85±1.26 years) with persistent CP underwent functional magnetic resonance imaging in a within-subject randomised control design to investigate whether, compared to placebo, a single-dose of intranasal oxytocin could 'shift' abnormal neural processing to fear. Oxytocin failed to reduce amygdala hypoactivity to fearful faces, but increased activation in the posterior cingulate cortex / precuneus to happy faces. These findings tentatively suggest that intranasal oxytocin may promote a more neurotypical profile in treatment-resistant CP children, therefore, supporting the merit of investigating oxytocin in further larger clinical studies in this population.

Is Being Male a Marker of Aggression? Evidence for the Decoupling of Sex and Gender Role Orientation

OBJECTIVES

This study explores whether sex differences in reactive aggression (RA) and proactive aggression (PA) are attributable to sex, gender role orientation, or their interaction and explores the neuroanatomical characteristics of these sex differences.

METHODS

In a sample of 108 males and 126 females, we examined the sex-by-gender role orientation interaction on RA, PA, and brain gray matter volume (GMV). Then, we explored the relationship between aggression and regional GMV.

RESULTS

When the effects of sex and gender role orientation on aggression were disentangled, there were no sex differences in RA, regardless of gender role orientation. However, sex differences (male > female) in PA were observed within the masculine group but not within the feminine group. Brain imaging results revealed sex differences (male > female) on the right inferior frontal gyrus GMV, a region involved in cognitive control, within the masculine group. Moreover, a negative association between PA and the right inferior frontal gyrus GMV was observed in masculine females rather than masculine males.

CONCLUSIONS

These findings indicate that gender role orientation has a more significant effect on aggression than sex, particularly with regard to PA, and hint that the goal of cognitive control involved in displaying PA differs in masculine males and masculine females.

Unique versus shared neural correlates of externalizing psychopathology in late childhood

Childhood externalizing psychopathology is heterogeneous. Symptom variability in conduct disorder (CD), oppositional defiant disorder (ODD), attention-deficit/hyperactivity disorder (ADHD), and callous-unemotional (CU) traits designate different subgroups of children with externalizing problems who have specific treatment needs. However, CD, ODD, ADHD, and CU traits are highly comorbid. Studies need to generate insights into shared versus unique risk mechanisms, including through the use of functional magnetic resonance imaging (fMRI). In this study, we tested whether symptoms of CD, ODD, ADHD, and CU traits were best represented within a bifactor framework, simultaneously modeling shared (i.e., general externalizing problems) and unique (i.e., symptom-specific) variance, or through a four-correlated factor or second-order factor model. Participants (N = 11,878, age, M = 9 years) were from the Adolescent Brain and Cognitive Development Study. We used questionnaire and functional magnetic resonance imaging data (emotional N-back task) from the baseline assessment. A bifactor model specifying a general externalizing and specific CD, ODD, ADHD, and CU traits factors demonstrated the best fit. The four-correlated and second-order factor models both fit the data well and were retained for analyses. Across models, reduced right amygdala activity to fearful faces was associated with more general externalizing problems and reduced dorsolateral prefrontal cortex activity to fearful faces was associated with higher CU traits. ADHD scores were related to greater right nucleus accumbens activation to fearful and happy faces. Results give insights into risk mechanisms underlying comorbidity and heterogeneity within externalizing psychopathology. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Relationships between Grey Matter Volume in the Bilateral Superior Frontal Gyrus and Reactive Aggression Varied by Level of Traditional Masculinity

Although previous behavioral studies have associated reactive aggression (RA) and proactive aggression (PA) with traditional masculinity, further investigation is needed into the traditional masculinity-linked neuroanatomical characteristics of RA and PA. This study analyzed the traditional masculinity-by-aggression interaction in 705 participants (350 men) by measuring grey matter volume (GMV). We have expanded on previous studies and found that traditional masculinity was not associated with RA and PA when not controlled for traditional femininity. However, the association appeared when controlling for it. Furthermore, we found significant traditional masculinity-by-RA interactions on the GMV in the bilateral superior frontal gyrus, a region known to be involved in cognitive control. When traditional masculinity scores were 1 standard deviation above the mean, there was a positive correlation between RA and the GMV in the bilateral superior frontal gyrus. Conversely, when traditional masculinity scores were 1 standard deviation below the mean, there was a negative correlation between RA and the GMV in the region. However, no traditional masculinity-linked neuroanatomical characteristics of PA were found. The results indicated that individuals with high/low traditional masculinity perceived RA as a different outcome (gain or loss) of self-control. The results supported an opportunity to develop prevention or intervention strategies for RA.

Psychopathy and gaze cueing

BACKGROUND AND OBJECTIVES

Psychopathic traits - and especially callous affective features - have been linked to altered processing of others' emotional expressions, and to reduced attention to the eyes. Despite the importance of gaze cueing (i.e., the tendency to orient attention toward where someone else is looking) for social functioning, few studies have investigated relationships between psychopathic traits and gaze cueing, and whether facial emotional expression influence these relationships, obtaining mixed results. To address this gap, the present study aimed to evaluate associations between psychopathic traits and gaze cueing for emotional and neutral expressions.

METHODS

65 non-clinical male participants (Mage = 27.3 years) completed two self-report measures of psychopathy and performed laboratory tasks to assess gaze-cueing for emotional vs. neutral faces and an arrow-cueing task as a comparison.

RESULTS

Linear mixed models showed no significant associations of emotional (versus neutral) expressions, or psychopathy trait dimensions, with either gaze cueing or arrow cueing.

LIMITATIONS

Reliance on a convenience sample of non-clinical men, assessed with self-reports measures of psychopathy, and using static emotional stimuli limit the generalizability of our findings.

CONCLUSIONS

Findings suggest that psychopathic traits are not associated with individual differences in following others' gaze to direct attention, and that there was no advantage for affective relative to neutral expressions.

The neurofunctional basis of human aggression varies by levels of femininity

Aggression can be categorized into reactive aggression (RA) and proactive aggression (PA) based on their underlying motivations. However, previous research has rarely identified the relationship between femininity and RA/PA, and there is a lack of understanding regarding the femininity-related neurofunctional basis of these aggressive behaviors. Thus, this study first examined the relationships between femininity and aggression, then explored the aggression-by-femininity interactions on the fractional amplitude of low-frequency fluctuations using resting-state fMRI among 705 university participants (mean age = 19.14 ± 0.99). The behavioral data indicated that femininity was more negatively associated with RA and PA when masculinity was controlled for. Additionally, the neural data revealed that femininity-specific relationships of RA in the left middle occipital gyrus (i.e. individuals with low femininity had positive relationships between RA and the left middle occipital gyrus, whereas those with high femininity had negative relationships) as well as of PA in the left middle frontal gyrus (i.e. individuals with high femininity showed significant negative relationships, whereas those with low femininity did not exhibit significant relationships). These findings reflect that individuals with varying levels of femininity exhibit distinct neural bases when expressing different subtypes of aggression, which are associated with societal expectations of gender.

Emotion Identification for Self and Other Associated with Callous-Unemotional Traits and Sex Differences in Early Adolescents

Callous-unemotional traits (CU) associates with impairments in emotional responsivity. However, there is less evidence on associations with specific emotions and sex differences utilizing both self and other oriented emotional stimuli. Given that the nuance of associations with specific emotions (including sex effects) is critical for understanding core impairments of this antisocial phenotype, the current study employed a behavioral paradigm with both self and other emotional stimuli for specific emotions (happy, sad, anger, fear, neutral) with a sample of male and female early adolescents (females = 51%, age = 12.86 ± 0.75). We examined accuracy and reaction times on this task, along with moderating effects of sex, in relation to CU traits. Results indicate CU traits associated with overall self-emotions negatively and sex moderated CU traits negative association with recognizing others overall emotions. CU traits negatively associated with accurate identification of both self and other emotions (happy, sad, and fear). Sex moderated all other emotion identification but only sad emotions for self. No reaction time differences were found. These findings evidence important nuance in CU traits and sex effects with identifying self and other emotions. Results have important implications for clinical understanding of sex differences in CU traits that require further consideration.

Brain Anatomy in Boys with Conduct Disorder: Differences Among Aggression Subtypes

Aggression is a core feature of conduct disorder (CD), but the motivation, execution of aggression may vary. A deeper understanding of the neural substrates of aggressive behaviours is critical for effective clinical intervention. Seventy-six Boys with CD (50 with impulsive aggression (I-CD) and 26 with premeditated aggression (P-CD)) and 69 healthy controls (HCs) underwent a structural MRI scan and behavioural assessments. Whole-brain analyses revealed that, compared to HCs, the I-CD group showed significant cortical thinning in the right frontal cortex, while the P-CD group demonstrated significant folding deficits in the bilateral superior parietal cortex. Both types of aggression negatively correlated with the left amygdala volume, albeit in different ways. The present results demonstrated that the complex nature of aggression relies on differentiated anatomical substrates, highlighting the importance of exploring differential circuit-targeted interventions for CD patients.

Potential sensitive period effects of maltreatment on amygdala, hippocampal and cortical response to threat

Childhood maltreatment is a leading risk factor for psychopathology, though it is unclear why some develop risk averse disorders, such as anxiety and depression, and others risk-taking disorders including substance abuse. A critical question is whether the consequences of maltreatment depend on the number of different types of maltreatment experienced at any time during childhood or whether there are sensitive periods when exposure to particular types of maltreatment at specific ages exert maximal effects. Retrospective information on severity of exposure to ten types of maltreatment during each year of childhood was collected using the Maltreatment and Abuse Chronology of Exposure scale. Artificial Intelligence predictive analytics were used to delineate the most important type/time risk factors. BOLD activation fMRI response to threatening versus neutral facial images was assessed in key components of the threat detection system (i.e., amygdala, hippocampus, anterior cingulate, inferior frontal gyrus and ventromedial and dorsomedial prefrontal cortices) in 202 healthy, unmedicated, participants (84 M/118 F, 23.2 ± 1.7 years old). Emotional maltreatment during teenage years was associated with hyperactive response to threat whereas early childhood exposure, primarily to witnessing violence and peer physical bullying, was associated with an opposite pattern of greater activation to neutral than fearful faces in all regions. These findings strongly suggest that corticolimbic regions have two different sensitive period windows of enhanced plasticity when maltreatment can exert opposite effects on function. Maltreatment needs to be viewed from a developmental perspective in order to fully comprehend its enduring neurobiological and clinical consequences.

Emotion recognition profiles in clusters of youth based on levels of callous-unemotional traits and reactive and proactive aggression

Youth with disruptive behavior showing high callous-unemotional (CU) traits and proactive aggression are often assumed to exhibit distinct impairments in emotion recognition from those showing mainly reactive aggression. Yet, reactive and proactive aggression and CU traits may co-occur to varying degrees across individuals. We aimed to investigate emotion recognition in more homogeneous clusters based on these three dimensions. In a sample of 243 youth (149 with disruptive behavior problems and 94 controls) aged 8-18 years, we used model-based clustering on self-report measures of CU traits and reactive and proactive aggression and compared the resulting clusters on emotion recognition (accuracy and response bias) and working memory. In addition to a Low and Low-Moderate symptom cluster, we identified two high CU clusters. The CU-Reactive cluster showed high reactive and low-to-medium proactive aggression; the CU-Mixed cluster showed high reactive and proactive aggression. Both CU clusters showed impaired fear recognition and working memory, whereas the CU-Reactive cluster also showed impaired recognition of disgust and sadness, partly explained by poor working memory, as well as a response bias for anger and happiness. Our results confirm the importance of CU traits as a core dimension along which youth with disruptive behavior may be characterized, yet challenge the view that high CU traits are closely linked to high proactive aggression per se. Notably, distinct neurocognitive processes may play a role in youth with high CU traits and reactive aggression with lower versus higher proactive aggression.

Different whole-brain functional connectivity correlates of reactive-proactive aggression and callous-unemotional traits in children and adolescents with disruptive behaviors

BACKGROUND

Disruptive behavior in children and adolescents can manifest as reactive aggression and proactive aggression and is modulated by callous-unemotional traits and other comorbidities. Neural correlates of these aggression dimensions or subtypes and comorbid symptoms remain largely unknown. This multi-center study investigated the relationship between resting state functional connectivity (rsFC) and aggression subtypes considering comorbidities.

METHODS

The large sample of children and adolescents aged 8-18 years (n = 207; mean age = 13.30±2.60 years, 150 males) included 118 cases with disruptive behavior (80 with Oppositional Defiant Disorder and/or Conduct Disorder) and 89 controls. Attention-deficit/hyperactivity disorder (ADHD) and anxiety symptom scores were analyzed as covariates when assessing group differences and dimensional aggression effects on hypothesis-free global and local voxel-to-voxel whole-brain rsFC based on functional magnetic resonance imaging at 3 Tesla.

RESULTS

Compared to controls, the cases demonstrated altered rsFC in frontal areas, when anxiety but not ADHD symptoms were controlled for. For cases, reactive and proactive aggression scores were related to global and local rsFC in the central gyrus and precuneus, regions linked to aggression-related impairments. Callous-unemotional trait severity was correlated with ICC in the inferior and middle temporal regions implicated in empathy, emotion, and reward processing. Most observed aggression subtype-specific patterns could only be identified when ADHD and anxiety were controlled for.

CONCLUSIONS

This study clarifies that hypothesis-free brain connectivity measures can disentangle distinct though overlapping dimensions of aggression in youths. Moreover, our results highlight the importance of considering comorbid symptoms to detect aggression-related rsFC alterations in youths.

Mediating effect of amygdala activity on response to fear vs. happiness in youth with significant levels of irritability and disruptive mood and behavior disorders

Introduction

Irritability, characterized by a tendency to exhibit increased anger, is a common clinical problem in youth. Irritability is a significant clinical issue in youth with various psychiatric diagnoses, especially disruptive behavior, and mood disorders (Attention-Deficit/Hyperactivity Disorder, Oppositional Defiant Disorder, Conduct Disorder, and Disruptive Mood Dysregulation Disorder). Although there have been previous studies focusing on functional alteration in the amygdala related to irritability, there is no comprehensive model between emotional, neuronal, and behavioral characteristics.

Methods

Using an functional magnetic resonance imaging (fMRI) procedure, we investigated the relationships between behavioral irritability, selective impairments in processing facial emotions and the amygdala neural response in youth with increased irritability. Fifty-nine youth with disruptive mood and behavior disorder completed a facial expression processing task with an event-related fMRI paradigm. The severity of irritability was evaluated using the Affective Reactivity Index.

Results

In the result of behavioral data, irritability, and reaction time (RT) differences between interpreting negative (fear) and positive (happiness) facial expressions were positively correlated. In the fMRI result, youth showed higher activation in the right cingulate gyrus, bilateral cerebellum, right amygdala, right precuneus, right superior frontal gyrus, right middle occipital gyrus, and middle temporal gyrus, during the happiness condition vs. fear condition. No brain region exhibited greater activation in the fear than in the happiness conditions. In the result of the mediator analysis, increased irritability was associated with a longer RT toward positive vs. negative facial expressions. Irritability was also positively associated with the difference in amygdala blood oxygen level-dependent responses between the two emotional conditions (happiness > fear). This difference in amygdala activity mediated the interaction between irritability and the RT difference between negative and positive facial expressions.

Discussion

We suggest that impairment in the implicit processing of facial emotional expressions with different valences causes distinct patterns of amygdala response, which correlate with the level of irritability. These results broaden our understanding of the biological mechanism of irritability at the neural level and provide information for the future direction of the study.

Empathy deficits, callous-unemotional traits and structural underpinnings in autism spectrum disorder and conduct disorder youth

Distinct empathy deficits are often described in patients with conduct disorder (CD) and autism spectrum disorder (ASD) yet their neural underpinnings and the influence of comorbid Callous-Unemotional (CU) traits are unclear. This study compares the cognitive (CE) and affective empathy (AE) abilities of youth with CD and ASD, their potential neuroanatomical correlates, and the influence of CU traits on empathy. Adolescents and parents/caregivers completed empathy questionnaires (N = 148 adolescents, mean age = 15.16 years) and T1 weighted images were obtained from a subsample (N = 130). Group differences in empathy and the influence of CU traits were investigated using Bayesian analyses and Voxel-Based Morphometry with Threshold-Free Cluster Enhancement focusing on regions involved in AE (insula, amygdala, inferior frontal gyrus and cingulate cortex) and CE processes (ventromedial prefrontal cortex, temporoparietal junction, superior temporal gyrus, and precuneus). The ASD group showed lower parent-reported AE and CE scores and lower self-reported CE scores while the CD group showed lower parent-reported CE scores than controls. When accounting for the influence of CU traits no AE deficits in ASD and CE deficits in CD were found, but CE deficits in ASD remained. Across all participants, CU traits were negatively associated with gray matter volumes in anterior cingulate which extends into the mid cingulate, ventromedial prefrontal cortex, and precuneus. Thus, although co-occurring CU traits have been linked to global empathy deficits in reports and underlying brain structures, its influence on empathy aspects might be disorder-specific. Investigating the subdimensions of empathy may therefore help to identify disorder-specific empathy deficits.

Age-related brain deviations and aggression

BACKGROUND

Disruptive behavior disorders (DBD) are heterogeneous at the clinical and the biological level. Therefore, the aims were to dissect the heterogeneous neurodevelopmental deviations of the affective brain circuitry and provide an integration of these differences across modalities.

METHODS

We combined two novel approaches. First, normative modeling to map deviations from the typical age-related pattern at the level of the individual of (i) activity during emotion matching and (ii) of anatomical images derived from DBD cases (n = 77) and controls (n = 52) aged 8-18 years from the EU-funded Aggressotype and MATRICS consortia. Second, linked independent component analysis to integrate subject-specific deviations from both modalities.

RESULTS

While cases exhibited on average a higher activity than would be expected for their age during face processing in regions such as the amygdala when compared to controls these positive deviations were widespread at the individual level. A multimodal integration of all functional and anatomical deviations explained 23% of the variance in the clinical DBD phenotype. Most notably, the top marker, encompassing the default mode network (DMN) and subcortical regions such as the amygdala and the striatum, was related to aggression across the whole sample.

CONCLUSIONS

Overall increased age-related deviations in the amygdala in DBD suggest a maturational delay, which has to be further validated in future studies. Further, the integration of individual deviation patterns from multiple imaging modalities allowed to dissect some of the heterogeneity of DBD and identified the DMN, the striatum and the amygdala as neural signatures that were associated with aggression.

Cognitive Mechanisms Underlying Prosocial Decision Making in Callous-Unemotional Traits

Callous-unemotional (CU) traits are characterized by a lack of prosocial emotions, which has been demonstrated with prosocial behavior paradigms. While shaping our understanding of prosocial behavior in youth with CU traits, most of this work relies on outcomes that don't reliably capture cognitive processes during prosocial behavior. Examining prosocial cognitive processes can cue researchers into cognitive mechanisms underlying core impairments of CU traits. Drift diffusion modeling is a valuable tool for elucidating more precise outcomes of latent cognitive processes during forced choice tasks such as drift rate (information accumulation toward a decision boundary) and threshold separation (amount of information considered) as well as metrics outside of the decision-making processing including bias (starting point in decision process) and non-decision time (cognitive processes outside of choice). In a sample of 87 adolescents (12-14, 49% female) we applied diffusion modeling to a prosocial behavior task in which participants either accepted or rejected trials where a real monetary value was given to them and taken away from a charity (self-serving trial) or money was given to a charity and taken from them (donation trial). Results revealed that CU traits associated with information accumulation toward accepting self-serving trials. Exploratory sex differences suggested males trended toward rejecting donation trials and females considered more information during self-serving trials. CU trait associations were independent of conduct problems. Results suggest a unique cognitive profile that are differentiated by sex at higher CU traits when making prosocial decisions involving knowledge accumulation toward self-serving decisions.

Affective theory of mind impairments underlying callous-unemotional traits and the role of cognitive control

Affective theory of mind (aToM) impairments associated with the youth antisocial phenotype callous-unemotional (CU) traits predict antisocial behaviour above CU traits alone. Importantly, CU traits associate with decrements in complex but not basic aToM. aToM is modulated by cognitive control and CU traits associate with cognitive control impairments; thus, cognitive control is a plausible mechanism underlying aToM impairments in CU traits. Because cognitive control is dependent on the availability of cognitive resources, youth with CU traits may have difficulty with allocating cognitive resources under greater demands that impact complex aToM. To test this, 81 participants (ages 12-14, Female = 51.8%, Male = 48.2%) were recruited to complete a behavioural paradigm that involved an initial aToM task with complex and basic emotions followed by placing additional demands on cognitive control and a final repeat of the same aToM task. Results indicate adolescents higher in CU traits had intact basic aToM but less accuracy in complex aToM that worsened after taxing cognitive control; and this load only required a short duration to account for ToM decrements (200 ms [range 150-1600 ms]). These results demonstrate CU traits association with cognitive control limitations that impact complex aToM. This may partially explain antisocial behaviour associated with CU traits.

The role of anxiety and callous-unemotional traits in the relationship between externalizing behaviors and sleep problems in clinic-referred youth

In a growing body of literature, poor sleep quality has been associated with externalizing problems. In adults, anxiety was found to mediate the relationship, and callous-unemotional (CU) traits were found to moderate it. We sought to examine these relationships in a child population. We examined these relationships in 239 clinic-referred youth (age 6-17) in Singapore with externalizing behavior problems. Parent- but not child-rated sleep problems were associated with increased parent-rated externalizing problems. This association was partially mediated by anxiety. Unlike in adults, CU traits did not moderate the relationship. Sleep problems were associated with externalizing problems regardless of the level of CU traits. It is possible externalizing behaviors may lead children to internalize experiences, leading to anxiety about their behaviors. Another possibility is externalizing behaviors may lead to more stressful life experiences due to negative reactions children with externalizing behaviors receive from parents, teachers, or peers. Regardless, the partial mediation found indicates anxiety may be an important factor to consider in future interventions focused on improving sleep as a means to reduce externalizing problems.

Emotion processing in youths with conduct problems: an fMRI meta-analysis

Functional magnetic resonance imaging (fMRI) studies consistently indicate differences in emotion processing in youth with conduct problems. However, no prior meta-analysis has investigated emotion-specific responses associated with conduct problems. This meta-analysis aimed to generate an up-to-date assessment of socio-affective neural responding among youths with conduct problems. A systematic literature search was conducted in youths (ages 10-21) with conduct problems. Task-specific seed-based d mapping analyses examined responses to threatening images, fearful and angry facial expressions, and empathic pain stimuli from 23 fMRI studies, which included 606 youths with conduct problems and 459 comparison youths. Whole-brain analyses revealed youths with conduct problems relative to typically developing youths, when viewing angry facial expressions, had reduced activity in left supplementary motor area and superior frontal gyrus. Additional region of interest analyses of responses to negative images and fearful facial expressions showed reduced activation in right amygdala across youths with conduct problems. Youths with callous-unemotional traits also exhibited reduced activation in left fusiform gyrus, superior parietal gyrus, and middle temporal gyrus when viewing fearful facial expressions. Consistent with the behavioral profile of conduct problems, these findings suggest the most consistent dysfunction is found in regions associated with empathic responding and social learning, including the amygdala and temporal cortex. Youth with callous-unemotional traits also show reduced activation in the fusiform gyrus, consistent with reduced attention or facial processing. These findings highlight the potential role of empathic responding, social learning, and facial processing along with the associated brain regions as potential targets for interventions.

The Origins of the Dark—Hyperactivity and Negative Peer Relationships, an Objectively Lower Sleep Efficiency, and a Longer Sleep Onset Latency at Age Five Were Associated with Callous-Unemotional Traits and Low Empathy at Age 14

Background: Within the spectrum of emotional competencies, callous-unemotional traits are socially discouraged, while empathy is considered a socially much more accepted emotional trait. This holds particularly true for adolescents, who are still building up their social and emotional competencies. The aims of the present study were two-fold: First, longitudinally, to identify traits of behavioral problems and objective sleep dimensions at the age of 5 years to predict callous-unemotional traits and empathy at the age of 14 years. Second, cross-sectionally, to associate callous-unemotional traits and empathy with current insomnia, stress, and mental toughness. Methods: Preschoolers at the age of 5 years were contacted nine years later at the age of 14 years. At 5 years, parents rated their children’s behavior (Strength and Difficulties Questionnaire, SDQ); in parallel, children underwent a one-night sleep-EEG assessment. At the age of 14 years, adolescents completed a series of questionnaires covering callous-unemotional traits, insomnia, empathy, stress, and mental toughness. Results: A total of 77 adolescents (38.1% females) took part in the present study. Longitudinally, higher scores for hyperactivity at age 5 significantly predicted higher callous-unemotional traits at age 14. A higher score for negative peer relationships at age 5 significantly predicted lower scores for cognitive empathy at age 14. Further, objective sleep-EEG measures showed that a higher sleep efficiency and a shorter sleep latency was associated with lower scores for callousness. Cross-sectionally, higher scores for callous-unemotional traits were associated with higher insomnia and stress, while lower insomnia was associated with higher empathy. Mental toughness was unrelated to callous-unemotional traits and empathy. Conclusions: It appears that hyperactivity traits and negative peer relationships and more unfavorable objective sleep patterns at 5 years predicted socially discouraged callous-unemotional traits and low empathy during adolescence. Further, cross-sectionally at the age of 14, callous-unemotional traits, subjective poor sleep, and higher stress were associated.

Serotonin transporter availability in physically aggressive personality disordered patients: associations with trait and state aggression, and response to fluoxetine

RATIONALE

Characterizing the neuroanatomical basis of serotonergic abnormalities in severe, chronic, impulsive aggression will allow for rational treatment selection, development of novel therapeutics, and biomarkers to identify at-risk individuals.

OBJECTIVES

The aim of this study is to identify associations between regional serotonin transporter (5-HTT) availability and trait and state aggression, as well as response to the anti-aggressive effects of fluoxetine.

METHODS

We examined 5-HTT availability using positron emission tomography (PET) imaging with [¹¹C]DASB in personality disordered patients with current physical intermittent explosive disorder (IED; n = 18), and healthy comparison participants (HC; n = 11), in the anterior cingulate cortex (ACC), amygdala (AMY), ventral striatum (VST), and midbrain (MID). After PET imaging, IED patients were treated with fluoxetine 20 mg daily (n = 9) or placebo (n = 6) for 12 weeks. Trait and state aggression, trait callousness, and childhood trauma were assessed.

RESULTS

In IED patients, trait aggression was positively associated with [¹¹C]DASB binding in the ACC and VST; covarying for trait callousness and childhood trauma enhanced these correlations. Baseline state aggression was positively correlated with ACC [¹¹C]DASB in IED patients. Greater baseline VST [¹¹C]DASB binding predicted greater decreases in state aggression with fluoxetine treatment.

CONCLUSIONS

Consistent with prior reports, ACC 5-HTT is related to trait aggression, and adjusting for factors related to proactive (callousness) and reactive (childhood trauma) aggression subtypes further resolves this relationship. Novel findings of the study include a better understanding of the association between regional 5-HTT availability and state aggression, and the involvement of VST 5-HTT with trait aggression, and with the anti-aggressive effects of fluoxetine.

Association between lower-level of environmental lead exposure and reactive and proactive aggression in youth: Sex differences

Lead exposure during childhood has been associated with a variety of negative outcomes, including antisocial/aggressive behavior. However, different subtypes of antisocial behavior have been found to have different neurobiological correlates, and it is unclear whether lead exposure is related to specific subtypes of aggressive behavior. The objective of the study was to examine relationships between childhood blood lead levels (BLL) and proactive and reactive aggression. Further, given prior findings of sex differences in the effects of lead exposure, we examine whether there are sex differences in these relationships. In a sample of 818 youth (47.2% girls) ages 10-13 in China, we assessed BLL and administered the Reactive Proactive Aggression Questionnaire. Results show that BLLs were associated with reactive, but not proactive aggression. There was a significant interaction between BLL and sex in predicting aggression; boys with higher BLL scored higher in both proactive and reactive aggression than boys with lower BLL, but these differences were not present for girls. These findings suggest that lead exposure may have broad effects on antisocial behavior, but that boys may be more susceptible than girls. These findings may provide insights to identifying protective factors that could be potential targets for intervention.

Structural abnormalities in adolescents with conduct disorder and high versus low callous unemotional traits

There may be distinct conduct disorder (CD) etiologies and neural morphologies in adolescents with high callous unemotional (CU) traits versus low CU traits. Here, we employed surface-based morphometry methods to investigate morphological differences in adolescents diagnosed with CD [42 with high CU traits (CD-HCU) and 40 with low CU traits (CD-LCU)] and healthy controls (HCs, N = 115) in China. Whole-brain analyses revealed significantly increased cortical surface area (SA) in the left inferior temporal cortex and the right precuneus, but decreased SA in the left superior temporal cortex in the CD-LCU group, compared with the HC group. There were no significant cortical SA differences between the CD-HCU and the HC groups. Compared to the CD-HCU group, the CD-LCU group had a greater cortical thickness (CT) in the left rostral middle frontal cortex. Region-of-interest analyses revealed significant group differences in the right hippocampus, with CD-HCU group having lower right hippocampal volumes than HCs. We did not detect significant group differences in the amygdalar volume, however, the right amygdalar volume was found to be a significant moderator of the correlation between CU traits and the proactive aggression in CD patients. The present results suggested that the manifestations of CD differ between those with high CU traits versus low CU traits, and underscore the importance of sample characteristics in understanding the neural substrates of CD.

Selective Amygdala Hypoactivity to Fear in Boys With Persistent Conduct Problems After Parent Training

BACKGROUND

Parenting interventions reduce antisocial behavior (ASB) in some children with conduct problems (CPs), but not others. Understanding the neural basis for this disparity is important because persistent ASB is associated with lifelong morbidity and places a huge burden on our health and criminal justice systems. One of the most highly replicated neural correlates of ASB is amygdala hypoactivity to another person's fear. We aimed to assess whether amygdala hypoactivity to fear in children with CPs is remediated following reduction in ASB after successful treatment and/or if it is a marker for persistent ASB.

METHODS

We conducted a prospective, case-control study of boys with CPs and typically developing (TD) boys. Both groups (ages 5-10 years) completed 2 magnetic resonance imaging sessions (18 ± 5.8 weeks apart) with ASB assessed at each visit. Participants included boys with CPs following referral to a parenting intervention group and TD boys recruited from the same schools and geographical regions. Final functional magnetic resonance imaging data were available for 36 TD boys and 57 boys with CPs. Boys with CPs were divided into those whose ASB improved (n = 27) or persisted (n = 30) following the intervention. Functional magnetic resonance imaging data assessing fear reactivity were then analyzed using a longitudinal group (TD/improving CPs/persistent CPs) × time point (pre/post) design.

RESULTS

Amygdala hypoactivity to fear was observed only in boys with CPs who had persistent ASB and was absent in those whose ASB improved following intervention.

CONCLUSIONS

Our findings suggest that amygdala hypoactivity to fear is a marker for ASB that is resistant to change following a parenting intervention and a putative target for future treatments.

Amygdala-prefrontal connectivity in children with maladaptive aggression is modulated by social impairment

Aggressive behavior is common across childhood-onset psychiatric disorders and is associated with impairments in social cognition and communication. The present study examined whether amygdala connectivity and reactivity during face emotion processing in children with maladaptive aggression are moderated by social impairment. This cross-sectional study included a well-characterized transdiagnostic sample of 101 children of age 8-16 years old with clinically significant levels of aggressive behavior and 32 typically developing children without aggressive behavior. Children completed a face emotion perception task of fearful and calm faces during functional magnetic resonance imaging. Aggressive behavior and social functioning were measured by standardized parent ratings. Relative to controls, children with aggressive behavior showed reduced connectivity between the amygdala and the dorsolateral prefrontal cortex (PFC) during implicit emotion processing. In children with aggressive behavior, the association between reduced amygdala-ventrolateral PFC connectivity and greater severity of aggression was moderated by greater social impairment. Amygdala reactivity to fearful faces was also associated with severity of aggressive behavior for children without social deficits but not for children with social deficits. Social impairments entail difficulties in interpreting social cues and enacting socially appropriate responses to frustration or provocation, which increase the propensity for an aggressive response via diminished connectivity between the amygdala and the ventral PFC.

Mirror neurons and empathy-related regions in psychopathy: systematic review, meta-analysis, and a working model

Mirror neurons have been associated with empathy. People with psychopathic traits present low levels of empathy. To analyze this, a systematic review of fMRI studies of people with psychopathic traits during an emotional facial expression processing task was performed. The regions of interest were structures associated with the mirror neuron system: ventromedial prefrontal cortex (vmPFC), inferior parietal lobe (IPL), inferior frontal gyrus and superior temporal sulcus. The analysis was also extended to structures related to affective empathy (insula, amygdala and anterior cingulate cortex) and to two more emotional processing areas (orbitofrontal cortex and fusiform gyrus). Hypoactivation was more frequently observed in regions of the mirror neuron system from people with high psychopathic traits, as well as in the emotional processing structures, and those associated with affective empathy, except for the insula, where it presented higher activity. Differences were observed for all types of emotions. The results suggest that the mirror neuron system is altered in psychopathy and their relationship with affective empathy deficits is discussed.

How reliable are amygdala findings in psychopathy? A systematic review of MRI studies

The amygdala is a key component in predominant neural circuitry models of psychopathy. Yet, after two decades of neuroimaging research on psychopathy, the reproducibility of amygdala findings is questionable. We systematically reviewed MRI studies (81 of adults, 53 of juveniles) to determine the consistency of amygdala findings across studies, as well as within specific types of experimental tasks, community versus forensic populations, and the lowest- versus highest-powered studies. Three primary findings emerged. First, the majority of studies found null relationships between psychopathy and amygdala structure and function, even in the context of theoretically relevant tasks. Second, findings of reduced amygdala activity were more common in studies with low compared to high statistical power. Third, the majority of peak coordinates of reduced amygdala activity did not fall primarily within the anatomical bounds of the amygdala. Collectively, these findings demonstrate significant gaps in the empirical support for the theorized role of the amygdala in psychopathy and indicate the need for novel research perspectives and approaches in this field.

Reactive vs proactive aggression: A differential psychobiological profile? Conclusions derived from a systematic review

INTRODUCTION

Scholars have established subcategories of aggressive behavior in order to better understand this construct. Specifically, a classification based on motivational underpinnings makes it possible to differentiate between reactive and proactive aggression. Whereas reactive aggression is characterized by emotional lability, which means it is prone to impulsive reactions after provocation, proactive aggression is driven by low emotionality and high levels of instrumentality to obtain benefits. Some authors have conceived these two types as having a dichotomous nature, but others argue against this conceptualization, considering a complementary model more suitable. Hence, neuroscientific research might help to clarify discussions about their nature because biological markers do not present the same biases as psychological instruments.

AIM

The main objective of this study was to carry out a systematic review of studies that assess underlying biological markers (e.g., genes, brain, psychophysiological, and hormonal) of reactive and proactive aggression.

METHODS

To carry out this review, we followed PRISMA quality criteria for reviews, using five digital databases complemented by hand-searching.

RESULTS

The reading of 3993 abstracts led to the final inclusion of 157 papers that met all the inclusion criteria. The studies included allow us to conclude that heritability accounted for approximately 45% of the explained variance in both types of aggression, with 60% shared by both, especially, for overt and physical expression forms, and 10% specific to each type. Regarding allelic risk factors, whereas low functioning variants affecting serotonin transport and monoaminoxidase increased the risk of reactive aggression, high functioning variants were associated with proactive aggression. Furthermore, brain analysis revealed an overlap between the two types of aggression and alterations in the volume of the amygdala and temporal cortex. Moreover, high activation of the medial prefrontal cortex (PFC) facilitated proneness to both types of aggression equally. Whereas stimulation of the right ventrolateral (VLPFC) and dorsolateral (DLPFC) reduced proneness to aggression, inhibition of the left DLPFC increased it. Finally, psychophysiological and hormonal correlates in general did not clearly differentiate between the two types because they were equally related to each type (e.g., low basal cortisol and vagal variability in response to acute stress) CONCLUSIONS: This study reinforces the complementary model of both types of aggression instead of a dichotomous model. Additionally, this review also offers background about several treatments (i.e., pharmacological, non-invasive brain techniques…) to reduce aggression proneness.

The human fear paradox: Affective origins of cooperative care

Already as infants humans are more fearful than our closest living primate relatives, the chimpanzees. Yet heightened fearfulness is mostly considered maladaptive, as it is thought to increase the risk of developing anxiety and depression. How can this human fear paradox be explained? The fearful ape hypothesis presented herein stipulates that, in the context of cooperative caregiving and provisioning unique to human great ape group life, heightened fearfulness was adaptive. This is because from early in ontogeny fearfulness expressed and perceived enhanced care-based responding and provisioning from, while concurrently increasing cooperation with, mothers and others. This explanation is based on a synthesis of existing research with human infants and children, demonstrating a link between fearfulness, greater sensitivity to and accuracy in detecting fear in others, and enhanced levels of cooperative behaviors. These insights critically advance current evolutionary theories of human cooperation by adding an early-developing affective component to the human cooperative makeup. Moreover, the current proposal has important cultural, societal, and health implications, as it challenges the predominant view in Western, educated, industrialized, rich, and democratic (WEIRD) societies that commonly construe fearfulness as a maladaptive trait, potentially ignoring its evolutionary adaptive functions.

Raging Hormones: Why Age-Based Etiological Conceptualizations of the Development of Antisocial Behavior Are Insufficient

Developmental science, particularly developmental neuroscience, has substantially influenced the modern legal system. However, this science has typically failed to consider the role of puberty and pubertal hormones on development when considering antisocial behavior. This review describes major theoretical positions on the developmental neuroscience of antisocial behavior and highlights where basic developmental neuroscience suggests that the role of puberty and pubertal hormones should be considered. The implications of the current state of the science with respect to developmental neuroscience is considered, particularly what is known in light of development beyond puberty. This review shows that development continues to an older age for many youth than the legal system typically acknowledges. The plasticity of the brain that this continued development implies has implications for the outcome of interventions in the legal system in ways that have not been explored. Future directions for both developmental scientists and legal professions are recommended.

Examining Links Between Infant Parasympathetic Regulation during the Still-Face Paradigm and Later Callous-Unemotional Traits

Although research suggests that callous-unemotional (CU) traits are underpinned by deficits in social affiliation and reduced sensitivity to threat, there has been little investigation of the biophysiological regulatory mechanisms underlying these processes in infancy. The current study uses data from the Durham Child Health and Development Study (DCHD; n = 206) to examine whether and how the combination of infants' behavioral reactivity and levels of respiratory sinus arrhythmia (RSA), an indicator of parasympathetic nervous system functioning, during the still-face episode of the still-face paradigm at 6 months differentiates risk for CU traits and oppositional defiant behaviors (ODD) at age 3 years, as well as whether these relations vary by children's attachment security. Results indicate that reduced negative affect during the still-face episode at 6 months predicts higher CU traits (B = -0.28, β = -0.27, p = 0.003) and ODD (B = -0.35, β = -0.24, p = 0.007) at 3 years. Results also show that comparatively lower RSA, i.e. engaged parasympathetic system, predicts higher CU traits (B = -0.10, β = -0.34, p = 0.013), but not ODD. Tests of moderation suggest the combination of blunted negative affect but comparatively lower RSA levels during a social stressor constitutes risk for later CU traits for children who are also insecurely attached (simple slope = -0.70, t = 2.88, p = 0.006 at -1 SD). Findings contribute to our understanding of the complex and interactive risk processes which precede the development of CU traits.

Callous-unemotional traits in adolescents moderate neural network associations with empathy

Callous-unemotional (CU) traits in adolescents are a dimensional construct involving a symptom subset of empathy impairments amongst broader affective deficits. Higher CU trait scores associate with less cognitive and affective empathy; and brain regions linked with cognitive and affective empathy show aberrant function in those with CU traits. How CU traits impact the relationship between brain function and both cognitive and affective empathy in adolescents is less clear. Here we examine how functional properties of networks that support cognitive and affective empathy is moderated by CU traits. Eighty-four adolescents underwent resting-state fMRI scanning and completed self-reports for empathy (Interpersonal Reactivity Index) and CU traits (Inventory of Callous-Unemotional Traits). Analysis revealed that CU traits moderate the association between affective empathy and connectivity between the default mode-frontoparietal networks. Weaker between default mode-frontoparietal anticorrelation negatively associated with affective empathy at low to moderate CU traits. Those highest in CU traits had the lowest affective empathy; and negative associations for those highest in CU traits were insignificant as default mode-frontoparietal anticorrelation weakened. Our results indicate that functional properties of networks that support affective empathy is different at varying levels of CU traits. This novel finding demonstrates that CU traits presence changes the relationship between the brain and empathy.

The effects of callous-unemotional traits and aggression subtypes on amygdala activity in response to negative faces

BACKGROUND

Brain imaging studies have shown altered amygdala activity during emotion processing in children and adolescents with oppositional defiant disorder (ODD) and conduct disorder (CD) compared to typically developing children and adolescents (TD). Here we aimed to assess whether aggression-related subtypes (reactive and proactive aggression) and callous-unemotional (CU) traits predicted variation in amygdala activity and skin conductance (SC) response during emotion processing.

METHODS

We included 177 participants (n = 108 cases with disruptive behaviour and/or ODD/CD and n = 69 TD), aged 8-18 years, across nine sites in Europe, as part of the EU Aggressotype and MATRICS projects. All participants performed an emotional face-matching functional magnetic resonance imaging task.

RESULTS

Differences between cases and TD in affective processing, as well as specificity of activation patterns for aggression subtypes and CU traits, were assessed. Simultaneous SC recordings were acquired in a subsample (n = 63). Cases compared to TDs showed higher amygdala activity in response to negative faces (fearful and angry) v. shapes. Subtyping cases according to aggression-related subtypes did not significantly influence on amygdala activity; while stratification based on CU traits was more sensitive and revealed decreased amygdala activity in the high CU group. SC responses were significantly lower in cases and negatively correlated with CU traits, reactive and proactive aggression.

CONCLUSIONS

Our results showed differences in amygdala activity and SC responses to emotional faces between cases with ODD/CD and TD, while CU traits moderate both central (amygdala) and peripheral (SC) responses. Our insights regarding subtypes and trait-specific aggression could be used for improved diagnostics and personalized treatment.

Unique and interactive associations of proactive and reactive aggression with cortisol secretion

The association between aggressive behaviors and diurnal cortisol levels has been debated over the past two decades, as some studies found a negative link between the two, whereas others reported no or a positive association. One possible explanation for these contradictory results is that past studies failed to distinguish between proactive (PROA) and reactive (REA) aggression. The present study examined the unique and joint associations of PROA and REA with three diurnal cortisol indicators: awakening levels, awakening response, and diurnal change. Participants were 542 youths (55.4% girls) followed longitudinally. Teachers evaluated aggressive behaviors when participants were in Grades 4 and 6. In Grade 8, participants provided four saliva samples (i.e., awakening, 30 min thereafter, late afternoon, and bedtime) on four collection days. Controlling for several confounders, multilevel regression analyses revealed an inverse relation between PROA and the CAR in boys who displayed lower or moderate levels of REA, but not in those who exhibited higher levels of REA. No associations emerged with other cortisol indicators. These results are consistent with reports of lower physiological activity in individuals with PROA and underscore the confounding influence of REA in the association between the CAR and proactive aggression.

Neural response to aggressive and positive interactions in violent offenders and nonviolent individuals

BACKGROUND

Due to its severe negative consequences, human violence has been targeted by a vast number of studies. Yet, neurobiological mechanisms underlying violence are still widely unclear and it seems necessary to aim for high ecological validity to learn about mechanisms contributing to violence in real life.

METHODS

The present functional magnetic resonance imaging (fMRI) study investigated the neurofunction of individuals with a history of violent offenses compared with that of controls using a laboratory paradigm requesting individuals to empathically engage in videos depicting provocative aggressive and positive social interactions from a first-person perspective.

RESULTS

The contrast of aggressive vs. positive scenarios revealed midbrain activation patterns associated with caudal periaqueductal gray (PAG) in violent offenders; In controls, the rostral PAG was involved. Additionally, only in controls, this contrast revealed an involvement of the amygdaloidal complex. Moreover, in violent offenders the contrast of positive vs. aggressive situations revealed an involvement of areas in the insula, post-central gyrus and anterior cingulate cortex.

CONCLUSIONS

Our results support findings on the differential role of PAG subdivisions in response to threat and point to altered processing of positive social interactions in violent offenders. They further support the notion that changes in PAG recruitment might contribute to violent individuals "taking action" instead of freezing in case of threatening situations.

Increased amygdala and decreased frontolimbic r esting- s tate functional connectivity in children with aggressive behavior

Childhood maladaptive aggression is associated with disrupted functional connectivity within amygdala-prefrontal circuitry. In this study, neural correlates of childhood aggression were probed using the intrinsic connectivity distribution, a voxel-wise metric of global resting-state brain connectivity. This sample included 38 children with aggressive behavior (26 boys, 12 girls) ages 8-16 years and 21 healthy controls (14 boys, 6 girls) matched for age and IQ. Functional MRI data were acquired during resting state, and differential patterns of intrinsic functional connectivity were tested in a priori regions of interest implicated in the pathophysiology of aggressive behavior. Next, correlational analyses tested for associations between functional connectivity and severity of aggression measured by the Reactive-Proactive Aggression Questionnaire in children with aggression. Children with aggressive behavior showed increased global connectivity in the bilateral amygdala relative to controls. Greater severity of aggressive behavior was associated with decreasing global connectivity in the dorsal anterior cingulate and ventromedial prefrontal cortex. Follow-up seed analysis revealed that aggression was also positively correlated with left amygdala connectivity with the dorsal anterior cingulate, ventromedial and dorsolateral prefrontal cortical regions. These results highlight the potential role of connectivity of the amygdala and medial prefrontal and anterior cingulate cortices in modulating the severity of aggressive behavior in treatment-seeking children.

Conduct problems among children in low-income, urban neighborhoods: A developmental psychopathology- and RDoC-informed approach

Conduct problems are associated with numerous negative long-term psychosocial sequelae and are among the most frequent referrals for children's mental health services. Youth residing in low-income, urban communities are at increased risk for conduct problems, but not all youth in these environments develop conduct problems, suggesting heterogeneity in risk and resilience processes and developmental pathways. The present study used a developmental psychopathology- and Research Domain Criteria (RDoC)-informed approach for conceptualizing risk and resilience for conduct problems among children from low-income, urban neighborhoods. Participants were 104 children (M = 9.93 ± 1.22 years; 50% male; 96% African American, 4% Latinx). We assessed four constructs reflecting cognitive and neurobiological processes associated with conduct problems using multiple levels of analysis and informants: autonomic nervous system reactivity, limbic system/orbitofrontal cortical functioning, dorsolateral prefrontal cortical functioning, and conduct problems. Latent profile analysis identified four profiles: typically developing (TD, n = 34); teacher-reported conduct problems (TCP, n = 14); emotion processing (EP, n = 27); and emotion expression recognition (EER, n = 29). External validation analyses demonstrated that profiles differed on various indices of conduct problems in expected ways. The EP profile exhibited lower levels of emotional lability and callous–unemotional behaviors, and higher levels of prosocial behavior. The TD profile demonstrated elevated emotional lability. Implications for etiological and intervention models are presented.

Resting-state network topology characterizing callous-unemotional traits in adolescence

BACKGROUND

Callous-unemotional (CU) traits, a youth antisocial phenotype, are hypothesized to associate with aberrant connectivity (dis-integration) across the salience (SAL), default mode (DMN), and frontoparietal (FPN) networks. However, CU traits have a heterogeneous presentation and previous research has not modeled individual heterogeneity in resting-state connectivity amongst adolescents with CU traits. The present study models individual-specific network maps and examines topological features of individual and subgroup maps in relation to CU traits.

METHODS

Participants aged 13-17 (n = 84, male = 55%, female = 45%) completed resting-state functional connectivity and the inventory of callous-unemotional traits as part of the Nathan Klein Rockland study. A sparse network approach (GIMME) was used to derive individual-level and subgroup maps of all participants. We then examined heterogeneous network features, including positive and negative connection density, associated with CU traits.

RESULTS

Higher rates of CU traits increased probability of inclusion in one subgroup, which had the highest mean level of CU traits. Analysis of network features reveals less density (positive and negative) within the FPN and greater density between DMN-FPN associated with CU traits.

DISCUSSION

Findings indicate heterogeneous person-specific connections and some subgroup connections amongst adolescents associate with CU traits. Higher CU traits associate with lower density in the FPN, which has been associated with attention and inhibition, and higher density between the DMN-FPN, which have been linked with cognitive control, social working memory, and empathy. Our findings suggest less efficiency in FPN function which, when considered mechanistically, could result in difficulty suppressing DMN when task positive networks are engaged. This is an area for further exploration but could explain cognitive and socio-affective impairments in CU traits.

Parsing Associations Between Dimensions of Empathy and Reactive and Proactive Aggression

The broad dimension of empathy has been shown to underlie various forms of psychopathology, most extensively studied for the externalizing spectrum of psychopathology. However, associations between subdimensions of empathy and functions of aggression remain unclear. The current study (N = 409) aimed to investigate common and specific associations between a higher-order model of aggression, comprising reactive aggression (RA) and proactive aggression (PA) factors with an overarching general aggression factor, and item-level factor analytically derived dimensions of empathy: affective/self-oriented empathy and cognitive/other-oriented empathy. Results demonstrated specific and opposing associations between dimensions of empathy and the general aggression factor, such that affective/self-oriented empathy was positively associated, and cognitive/other-oriented empathy was negatively associated with general aggression. Affective/self-oriented empathy was positively associated with RA, whereas cognitive/other-oriented empathy was negatively associated with RA and PA. Results confirm the importance of considering the multidimensionality of empathy and aggression and suggest both common and distinct pathways from empathy to aggression.

Cold-Blooded and on Purpose: A Review of the Biology of Proactive Aggression

Proactive aggression (PA) is a planned and unprovoked form of aggression that is most often enacted for personal gain or in anticipation of a reward. Frequently described as "cold-blooded" or goal oriented, PA is thought to be associated with low autonomic arousal. With this view in mind, we performed a scoping review of the biological correlates of PA and identified 74 relevant articles. Physiological findings indicated a robust association between PA and reduced resting heart rate, and to a lesser extent a relationship between PA and decreased heart rate and skin conductance reactivity, perhaps indicating dampened sympathetic function. The twin literature identified PA as a heritable trait, but little evidence implicates specific genes in the pathogenesis of PA. Neuroimaging studies of PA pinpoint impaired amygdala function in the assessment and conditioning of aversive stimuli, which may influence the establishment of behavioral patterns. Nodes of the default mode network were identified as possible neural correlates of PA, suggesting that altered function of this network may be involved in the genesis of PA. Given the overlap of PA with reactive aggression and the overall behavioral complexity of PA, it is clear that multiple endophenotypes of PA exist. This comprehensive review surveys the most salient neurobiologically informed research on PA.

Heart-wired to be cold? Exploring cardiac markers of callous-unemotional traits in incarcerated offenders

Elevated callous-unemotional (CU) traits have been repeatedly identified in a subgroup of offenders that displays severe antisocial behavior; establishing physiological markers may help improve early identification and treatment efforts. This study examines to what extent baseline-resting heart rate (HR) and heart rate variability (HRV) can be used as markers of CU in incarcerated juvenile and adult offenders. CU traits were assessed using the Inventory of Callous-Unemotional traits. Results of the multiple hierarchical regression tests indicated that there was a small yet significant positive association between baseline HR and CU and negative association between HRV and CU in juvenile offenders with medium model effect sizes (R² = 0.115 for HR-CU; R² = 0.126 for HRV-CU). The cardiac markers were unrelated to CU in adult offenders. These findings are important because they demonstrate that impaired cardiac autonomic activity is related to CU traits in juveniles, suggesting that socioemotional processing difficulties should be considered in understanding these deficits. Future research should be conducted in large samples, under reactive and static conditions, while including cardiac covariates, to get more clarity on the interplay between biological systems and behavioral expression.

Reduced neural responsiveness to looming stimuli is associated with increased aggression

While neuro-cognitive work examining aggression has examined patients with conditions at increased risk for aggression or individuals self-reporting past aggression, little work has attempted to identify neuro-cognitive markers associated with observed/recorded aggression. The goal of the current study was to determine the extent to which aggression by youth in the first three months of residential care was associated with atypical responsiveness to threat stimuli. This functional MRI study involved 98 (68 male; mean age = 15.96 [sd = 1.52]) adolescents in residential care performing a looming threat task involving images of threatening and neutral human faces or animals that appeared to be either loom or recede. Level of aggression was negatively associated with responding to looming stimuli (irrespective of whether these were threatening or neutral) within regions including bilateral inferior frontal gyrus, right inferior parietal lobule, right superior/middle temporal gyrus and a region of right uncus proximal to the amygdala. These data indicate that aggression level is associated with a decrease in responsiveness to a basic threat cue-looming stimuli. Reduced threat responsiveness likely results in the individual being less able to represent the negative consequences that may result from engaging in aggression, thereby increasing the risk for aggressive episodes.

Alcohol and Cannabis Use Disorder Symptom Severity, Conduct Disorder, and Callous-Unemotional Traits and Impairment in Expression Recognition

Background: Alcohol and cannabis are commonly used by adolescents in the United States. Both alcohol use disorder (AUD) and cannabis use disorder (CUD) have been associated with reduced emotion expression recognition ability. However, this work has primarily occurred in adults and has not considered neuro-cognitive risk factors associated with conduct problems that commonly co-occur with, and precede, substance use. Yet, conduct problems are also associated with reduced emotion expression recognition ability. The current study investigated the extent of negative association between AUD and CUD symptom severity and expression recognition ability over and above any association of expression recognition ability with conduct problems [conduct disorder (CD) diagnostic status]. Methods: In this study, 152 youths aged 12.5-18 years (56 female; 60 diagnosed with CD) completed a rapid presentation morphed intensity facial expression task to investigate the association between relative severity of AUD/CUD and expression recognition ability. Results: Cannabis use disorder identification test (CUDIT) scores were negatively associated with recognition accuracy for higher intensity (particularly sad and fearful) expressions while CD diagnostic status was independently negatively associated with recognition of sad expressions. Alcohol use disorder identification test (AUDIT) scores were not significantly associated with expression recognition ability. Conclusions: These data indicate that relative severity of CUD and CD diagnostic status are statistically independently associated with reduced expression recognition ability. On the basis of these data, we speculate that increased cannabis use during adolescence may exacerbate a neuro-cognitive risk factor for the emergence of aggression and antisocial behavior.

Modulation of Amygdala Response by Cognitive Conflict in Adolescents with Conduct Problems and Varying Levels of CU Traits

Adolescents with conduct problems and low callous-unemotional traits are characterised by high levels of reactive aggression. Prior studies suggest that they can have exaggerated neural and behavioural responses to negative emotional stimuli, accompanied by compromised affect regulation and atypical engagement of prefrontal areas during cognitive control. This pattern may in part explain their symptoms. Clarifying how neurocognitive responses to negative emotional stimuli can be modulated in this group has potential translational relevance. We present fMRI data from a cognitive conflict task in which the requirement to visually scan emotional (vs. calm) faces was held constant across low and high levels of cognitive conflict. Participants were 17 adolescent males with conduct problems and low levels of callous-unemotional traits (CP/LCU); 17 adolescents with conduct problems and high levels of callous-unemotional traits (CP/HCU, who typically show blunted reactivity to fear), and 18 typically developing controls (age range 10-16). Control participants showed typical attenuation of amygdala response to fear relative to calm faces under high (relative to low) conflict, replicating previous findings in a healthy adult sample. In contrast, children with CP/LCU showed a reduced (left amygdala) or reversed (right amygdala) attenuation effect under high cognitive conflict conditions. Children with CP/HCU did not differ from controls. Findings suggest atypical modulation of amygdala response as a function of task demands, and raise the possibility that those with CP/LCU are unable to implement typical regulation of amygdala response when cognitive task demands are high.

Psychopathy

Psychopathy is a personality disorder characterized by a constellation of affective, interpersonal, lifestyle and antisocial features whose antecedents can be identified in a subgroup of young people showing severe antisocial behaviour. The prevalence of psychopathy in the general population is thought to be ~1%, but is up to 25% in prisoners. The aetiology of psychopathy is complex, with contributions of both genetic and environmental risk factors, and gene-environment interactions and correlations. Psychopathy is characterized by structural and functional brain abnormalities in cortical (such as the prefrontal and insular cortices) and subcortical (for example, the amygdala and striatum) regions leading to neurocognitive disruption in emotional responsiveness, reinforcement-based decision-making and attention. Although no effective treatment exists for adults with psychopathy, preliminary intervention studies targeting key neurocognitive disturbances have shown promising results. Given that psychopathy is often comorbid with other psychiatric disorders and increases the risk of physical health problems, educational and employment failure, accidents and criminality, the identification of children and young people at risk for this personality disorder and preventative work are important. Indeed, interventions that target the antecedents of psychopathic features in children and adolescents have been found to be effective.

Processing of emotional faces in sexual offenders with and without child victims: An eye-tracking study with pupillometry

Socio-affective dysfunction is a risk-factor for sexual offense recidivism. However, it remains unknown whether men who have sexually offended with and without child victims show differences in eye scan paths and autonomic responsivity while viewing facial expressions of emotion. We examined differences in accuracy of emotion recognition, eye movements, and pupil dilation responses between sex offenders with child victims, sex offenders without child victims, and a group of non-offenders living in the community. Sex offenders without child victims looked for longer at the eyes than sex offenders with child victims and non-offenders. Men without child victims also scored higher for psychopathy linked disinhibition, and these traits were associated with looking longer at the eyes of afraid faces. We found no evidence for group differences in accuracy, visual attention to the mouth, or pupil dilation responses. Our findings have implications for understanding the nature of socio-affective dysfunction in sexual offenders.

Impaired global efficiency in boys with conduct disorder and high callous unemotional traits

Callous unemotional (CU) traits differentiate subtypes of conduct disorder (CD). It has been suggested that CU traits may be related to topographical irregularities that hinder information integration. To date, there is limited evidence of whether CU traits may be associated with abnormal brain topology. In this study, 43 CD boys with high and low CU trait (CD-HCU, CD-LCU), and 46 healthy controls (HCs) were subjected to resting-state functional magnetic resonance imaging to investigate how CU trait level and conduct problems may be reflected in topological organization. Brain functional networks were constructed and network/nodal properties, including small-world properties and network/nodal efficiency, were calculated. Topological analysis revealed that, compared with HCs, CD-HCU group were characterized by decreased small-worldness (σ), decreased global efficiency, and increased path length (λ). These variables were similar between the CD-LCU and HC groups. Self-reported CU traits in CD patients correlated negatively with global efficiency and positively with λ. Regional analysis revealed diminished nodal efficiency in the right amygdala in the CD-HCU group compared with HCs. The present results suggest that disrupted global efficiency, together with a regional abnormality affecting the amygdala, may contribute to abnormal information processing and integration in adolescents with CD and high CU traits.

Callous-Unemotional Traits Do Not Predict Functional Family Therapy Outcomes for Adolescents With Behavior Problems

Despite the availability of evidence-based treatment models for adolescent behavior problems, little is known about the effectiveness of these programs for adolescents with callous-unemotional (CU) traits. Defined by lack of empathy, lack of guilt, flattened affect and lack of caring, CU traits have been linked to long-term anti-social behavior and unfavorable treatment outcomes and might be negatively related to outcomes in evidence-based programs such as Functional Family Therapy (FFT). This study used a single-group pre-post evaluation design with a sample of 407 adolescents (49.1% female, mean age = 14.4 years, SD = 1.9) receiving FFT to investigate whether outcomes in FFT are predicted by CU traits and to what extent reliable changes in CU traits can be observed. The results showed that although CU traits are related to increased problem severity at baseline, they predicted neither treatment dropout nor post-treatment externalizing behavior and family functioning. CU traits were related to diminished improvement ratings, in particular with respect to parental supervision. Reductions in CU traits were observed across the time of treatment, and these were most profound among adolescents with elevated levels of CU traits at baseline. Further research should investigate whether certain evidence-based treatment components are more suited for adolescents with CU, and if the addition of specific intervention elements for reducing CU-traits could further improve outcomes for this high-risk population.

Sex differences in medial prefrontal and parietal cortex structure in children with disruptive behavior

Sex differences in brain structure in children with disruptive behavior disorders (DBD) remain poorly understood. This study examined sex differences in gray matter volume in children with DBD in a priori regions-of-interest implicated in the pathophysiology of disruptive behavior. We then conducted a whole-brain analysis of cortical thickness to examine sex differences in regions not included in our hypothesis. Exploratory analyses investigated unique associations between structure, and dimensional measures of severity of disruptive behavior and callous-unemotional traits. This cross-sectional study included 88 children with DBD (30 females) aged 8-16 years and 50 healthy controls (20 females). Structural MRI data were analyzed using surface-based morphometry to test for interactions between sex and group. Multiple-regression analyses tested for sex-specific associations between structure, callous-unemotional traits, and disruptive behavior severity. Boys with DBD showed reduced gray matter volume in the left ventromedial prefrontal cortex (vmPFC) and reduced cortical thickness in the supramarginal gyrus, but not girls compared to respective controls. Dimensional analyses revealed associations between sex, callous-unemotional traits, and disruptive behavior for amygdala and vmPFC volume, and ventrolateral prefrontal cortex cortical thickness. Sex-specific differences in prefrontal structures involved in emotion regulation may support identification of neural biomarkers of disruptive behavior to inform target-based treatments.

Alcohol Use Disorder and Cannabis Use Disorder Symptomatology in Adolescents and Aggression: Associations With Recruitment of Neural Regions Implicated in Retaliation

BACKGROUND

Alcohol and cannabis are commonly used by adolescents in the United States. Both alcohol use disorder (AUD) and cannabis use disorder (CUD) have been associated with an increased risk of aggression. One form of aggression seen during retaliation is reactive aggression to social provocation. This study investigated the association between AUD and CUD symptom severity and recruitment of neural regions implicated in retaliation.

METHODS

In this study, 102 youths aged 13-18 years (67 male; 84 in residential care) completed self-report measures of aggression-related constructs and participated in a retaliation task during functional magnetic resonance imaging to investigate the association between relative severity of AUD/CUD and atypical recruitment of regions implicated in retaliation.

RESULTS

AUD Identification Test scores were positively associated with irritability and reactive aggression scores. CUD Identification Test scores were positively associated with callous-unemotional traits and both proactive and reactive aggression scores. In functional magnetic resonance imaging analyses, only AUD Identification Test (not CUD Identification Test) scores were associated with an exaggerated recruitment of regions implicated in retaliation (dorsomedial frontal, anterior insula cortices, caudate, and, to a lesser extent, periaqueductal gray).

CONCLUSIONS

These data suggest that relative severity of AUD is associated with a disinhibited, exaggerated retaliation response that relates to an increased risk for reactive aggression. Similar findings were not related to severity of CUD.

Eye gaze patterns and functional brain responses during emotional face processing in adolescents with conduct disorder

BACKGROUND

Conduct disorder (CD) is characterized by severe aggressive and antisocial behavior. Initial evidence suggests neural deficits and aberrant eye gaze pattern during emotion processing in CD; both concepts, however, have not yet been studied simultaneously. The present study assessed the functional brain correlates of emotional face processing with and without consideration of concurrent eye gaze behavior in adolescents with CD compared to typically developing (TD) adolescents.

METHODS

58 adolescents (23CD/35TD; average age = 16 years/range = 14-19 years) underwent an implicit emotional face processing task. Neuroimaging analyses were conducted for a priori-defined regions of interest (insula, amygdala, and medial orbitofrontal cortex) and using a full-factorial design assessing the main effects of emotion (neutral, anger, fear), group and the interaction thereof (cluster-level, p < .05 FWE-corrected) with and without consideration of concurrent eye gaze behavior (i.e., time spent on the eye region).

RESULTS

Adolescents with CD showed significant hypo-activations during emotional face processing in right anterior insula compared to TD adolescents, independent of the emotion presented. In-scanner eye-tracking data revealed that adolescents with CD spent significantly less time on the eye, but not mouth region. Correcting for eye gaze behavior during emotional face processing reduced group differences previously observed for right insula.

CONCLUSIONS

Atypical insula activation during emotional face processing in adolescents with CD may partly be explained by attentional mechanisms (i.e., reduced gaze allocation to the eyes, independent of the emotion presented). An increased understanding of the mechanism causal for emotion processing deficits observed in CD may ultimately aid the development of personalized intervention programs.