Aggression, psychopathy and free will from a cognitive neuroscience perspective

Monogenic human obesity syndromes

Neural circuits in the hypothalamus play a key role in the regulation of human energy homeostasis. A critical circuit involves leptin-responsive neurons in the hypothalamic arcuate nucleus (the infundibular nucleus in humans) expressing the appetite-suppressing neuropeptide proopiomelanocortin (POMC) and the appetite-stimulating Agouti-related peptide. In the fed state, the POMC-derived melanocortin peptide α-melanocyte-stimulating hormone stimulates melanocortin-4 receptors (MC4Rs) expressed on second-order neurons in the paraventricular nucleus of the hypothalamus (PVN). Agonism of MC4R leads to reduced food intake and increased energy expenditure. Disruption of this hypothalamic circuit by inherited mutations in the genes encoding leptin, the leptin receptor, POMC, and MC4R can lead to severe obesity in humans. The characterization of these and closely related genetic obesity syndromes has informed our understanding of the neural pathways by which leptin regulates energy balance, neuroendocrine function, and the autonomic nervous system. A broader understanding of these neural and molecular mechanisms has paved the way for effective mechanism-based therapies for patients whose severe obesity is driven by disruption of these pathways.

Untangling Intelligence, Psychopathy, Antisocial Personality Disorder, and Conduct Problems: A Meta–Analytic Review

Substantial research has investigated the association between intelligence and psychopathic traits. The findings to date have been inconsistent and have not always considered the multidimensional nature of psychopathic traits. Moreover, there has been a tendency to confuse psychopathy with other closely related, clinically significant disorders. The current study represents a meta–analysis conducted to evaluate the direction and magnitude of the association of intelligence with global psychopathy, as well as its factors and facets, and related disorders (i.e. antisocial personality disorder, conduct disorder, and oppositional defiant disorder). Our analyses revealed a small, significant, negative relationship between intelligence and total psychopathy ( r = −.07, p = .001). Analysis of factors and facets found differential associations, including both significant positive (e.g. interpersonal facet) and negative (e.g. affective facet) associations, further affirming that psychopathy is a multidimensional construct. Additionally, intelligence was negatively associated with antisocial personality disorder ( r = −.13, p = .001) and conduct disorder ( r = −.13, p = .001) but positively with oppositional defiant disorder ( r = .06, p = .001). There was significant heterogeneity across studies for most effects, but the results of moderator analyses were inconsistent. Finally, bias analyses did not find significant evidence for publication bias or outsized effects of outliers. © 2019 European Association of Personality Psychology

Neural deletion of Sh2b1 results in brain growth retardation and reactive aggression

Psychiatric disorders are associated with aberrant brain development and/or aggressive behavior and are influenced by genetic factors; however, genes that affect brain aggression circuits remain elusive. Here, we show that neuronal Src-homology-2 (SH2)B adaptor protein-1 ( Sh2b1) is indispensable for both brain growth and protection against aggression. Global and brain-specific deletion of Sh2b1 decreased brain weight and increased aggressive behavior. Global and brain-specific Sh2b1 knockout (KO) mice exhibited fatal, intermale aggression. In a resident-intruder paradigm, latency to attack was markedly reduced, whereas the number and the duration of attacks was significantly increased in global and brain-specific Sh2b1 KO mice compared with wild-type littermates. Consistently, core aggression circuits were activated to a higher level in global and brain-specific Sh2b1 KO males, based on c-fos immunoreactivity in the amygdala and periaqueductal gray. Brain-specific restoration of Sh2b1 normalized brain size and reversed pathologic aggression and aberrant activation of core aggression circuits in Sh2b1 KO males. SH2B1 mutations in humans were linked to aberrant brain development and behavior. At the molecular level, Sh2b1 enhanced neurotrophin-stimulated neuronal differentiation and protected against oxidative stress-induced neuronal death. Our data suggest that neuronal Sh2b1 promotes brain development and the integrity of core aggression circuits, likely through enhancing neurotrophin signaling.-Jiang, L., Su, H., Keogh, J. M., Chen, Z., Henning, E., Wilkinson, P., Goodyer, I., Farooqi, I. S., Rui, L. Neural deletion of Sh2b1 results in brain growth retardation and reactive aggression.

The neuropsychological contributors to psychopathic personality traits in adolescence

Research has consistently revealed that measures of psychopathy and psychopathic personality traits represent some of the most consistent predictors of violent criminal involvement. As a result, there has been a considerable amount of interest in trying to identify the various etiological factors related to psychopathy. The current study builds on this existing body of literature by examining the association between neuropsychological deficits and psychopathic personality traits. Data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care were analyzed. Adolescent psychopathic personality traits were measured with a 15-item scale drawn from the Youth Psychopathic Traits Inventory (YPI), whereas neuropsychological functioning was assessed with a number of standardized tests of cognitive skills. Analyses revealed that neuropsychological deficits were significantly related to psychopathy measures across all four measurement phases. Neuropsychological deficits also predicted scoring in the top 5% of psychopathic personality traits.

Intervening in the psychopath's brain

Psychopathy is a disorder involving personality and behavioral features associated with a high rate of violent aggression and recidivism. This paper explores potential psychopharmacological therapies to modulate dysfunctional neural pathways in psychopaths and reduce the incidence of their harmful behavior, as well as the ethical and legal implications of offering these therapies as an alternative to incarceration. It also considers whether forced psychopharmacological intervention in adults and children with psychopathic traits manifesting in violent behavior can be justified. More generally, the paper addresses the question of how to weigh the psychopath's presumptive right to non-interference in his brain and mind against the public interest in avoiding harm.

The genetic and environmental covariation among psychopathic personality traits, and reactive and proactive aggression in childhood

The present study investigated the genetic and environmental covariance between psychopathic personality traits with reactive and proactive aggression in 9- to 10-year-old twins (N = 1,219). Psychopathic personality traits were assessed with the Child Psychopathy Scale (D. R. Lynam, 1997), while aggressive behaviors were assessed using the Reactive Proactive Questionnaire (A. Raine et al., 2006). Significant common genetic influences were found to be shared by psychopathic personality traits and aggressive behaviors using both caregiver (mainly mother) and child self-reports. Significant genetic and nonshared environmental influences specific to psychopathic personality traits and reactive and proactive aggression were also found, suggesting etiological independence among these phenotypes. Additionally, the genetic relation between psychopathic personality traits and aggression was significantly stronger for proactive than reactive aggression when using child self-reports.

"Cool" inferior frontostriatal dysfunction in attention-deficit/hyperactivity disorder versus "hot" ventromedial orbitofrontal-limbic dysfunction in conduct disorder: a review

Attention-deficit/hyperactivity disorder (ADHD) and conduct disorder overlap behaviorally, clinically, and cognitively. An important question of potential future clinical relevance is whether these two overlapping disorders are mediated by similar or distinct underlying brain substrates. This article reviews the modern neuroimaging literature on brain structure, function, and connectivity in both disorders, shaping out commonalities and differences. Findings show that ADHD is characterized predominantly by abnormalities in inferior frontal, striatal, parietotemporal, and cerebellar regions and networks that mediate "cool"-cognitive, i.e., inhibitory, attention and timing functions associated with the disorder. Conduct disorder, by contrast, has consistently been associated with abnormalities of the "hot" paralimbic system that regulates motivation and affect, comprising lateral orbital and ventromedial prefrontal cortices, superior temporal lobes, and underlying limbic structures, most prominently the amygdala. Direct comparisons in functional imaging show that these associations of cool inferior fronto-striato-cerebellar dysfunction in ADHD and of hot orbitofrontal-paralimbic dysfunction in conduct disorder are disorder-specific. There is, hence, evidence for dissociated underlying pathophysiologies for these two disorders that may have implications for future anatomy-based differential diagnosis and prevention and intervention.

Neuroimaging and Responsibility Assessments

Could neuroimaging evidence help us to assess the degree of a person's responsibility for a crime which we know that they committed? This essay defends an affirmative answer to this question. A range of standard objections to this high-tech approach to assessing people's responsibility is considered and then set aside, but I also bring to light and then reject a novel objection-an objection which is only encountered when functional (rather than structural) neuroimaging is used to assess people's responsibility.

Toddler self-regulation skills predict risk for pediatric obesity

OBJECTIVE

To investigate the role of early self-regulation skills, including emotion regulation, sustained attention and inhibitory control/reward sensitivity, in predicting pediatric obesity in early childhood.

METHOD

Participants for this study included 57 children (25 girls) obtained from three different cohorts participating in a larger ongoing longitudinal study. At 2 years of age, participants participated in several laboratory tasks designed to assess their self-regulation skills. Height and weight measures were collected when children were 2 and 5.5 years of age.

RESULTS

Self-regulation skills in toddlerhood were predictive of both normal variations in body mass index (BMI) development and pediatric obesity. Specifically, emotion regulation was the primary self-regulation skill involved in predicting normative changes in BMI as no effects were found for sustained attention or inhibitory control/reward sensitivity. However, both emotion regulation and inhibitory control/reward sensitivity predicted more extreme weight problems (that is, pediatric obesity), even after controlling for 2-year BMI. Thus, toddlers with poor emotion regulation skills and lower inhibitory control skills/higher reward sensitivity were more likely to be classified as overweight/at risk at 5.5 years of age.

CONCLUSION

Early self-regulation difficulties across domains (that is, behavioral and emotional) represent significant individual risk factors for the development of pediatric obesity. Mechanisms by which early self-regulation skills may contribute to the development of pediatric obesity are discussed.

Neuroscience and the law: philosophical differences and practical constraints

Controversies surrounding the value of neuroscience as forensic evidence are explored from the perspective of the philosophy of mind, as well as from a practical analysis of the state of the scientific research literature. At a fundamental philosophical level there are profound differences in how law and neuroscience view the issue of criminal responsibility along the continuum from free will to determinism. At a more practical level, significant limitations in the current state of neuroimaging research constrain its ability to inform legal decision-making. Scientifically supported and unsupported forensic applications for brain imaging are discussed, and recommendations for forensic report writing are offered.