MAOA genotype modulates default mode network deactivation during inhibitory control

Integrative metabolomics and network pharmacology to study the preventative impact of dioscin treatment on hyperuricemia

This work aims to combine network pharmacology and metabolomics to explore the mechanism of action of dioscin on hyperuricemia (HUA). The preventative impact of dioscin on HUA and its putative mechanism were examined using network pharmacological analysis and metabonomics. Network pharmacology study further pointed out the potential targets of dioscin after a review of the relevant biomarker pathways discovered by metabolomic analysis. Molecular docking was then used to examine how the active chemicals interacted with the target proteins. The therapeutic effect of dioscin on HUA was shown to be mediated by 13 potentially important metabolites as a result of metabonomic research. Most of these metabolites are regulated after dioscin therapy to help patients recover. Based on network pharmacology, we identified 10 central genes, which is partly in agreement with metabolomics data. Using metabolomics and network pharmacology, this study investigated the primary targets and mechanisms of dioscin in the treatment of HUA. It is advantageous that dioscin has been developed as an additional drug for the treatment of HUA.

Bright side of the MAOA-uVNTR on trait and situational forgiveness

The stress-and-coping theory of forgiveness posits that forgiveness and aggression are alternative ways of coping with stress of interpersonal offences. Inspired by the link between aggression and MAOA-uVNTR (a genetic variant involving in catabolism of monoamines), we investigated the relationship between this variant and forgiveness with two studies. Study 1 examined the relationship between the MAOA-uVNTR and trait forgiveness in students, and study 2 examined the effect of this variant on third-party forgiveness in response to situational offences in male inmates. The results showed that the MAOA-H (a high activity allele) was associated with higher trait forgiveness in male students and greater third-party forgiveness to accidentally committed harm and attempted but failed harm in male inmates than the MAOA-L. These findings highlight the bright side of MAOA-uVNTR on trait and situational forgiveness.

Structural and functional brain networks of individual differences in trait anger and anger control: An unsupervised machine learning study

The ability to experience, use and eventually control anger is crucial to maintain well-being and build healthy relationships. Despite its relevance, the neural mechanisms behind individual differences in experiencing and controlling anger are poorly understood. To elucidate these points, we employed an unsupervised machine learning approach based on independent component analysis to test the hypothesis that specific functional and structural networks are associated with individual differences in trait anger and anger control. Structural and functional resting state images of 71 subjects as well as their scores from the State-Trait Anger Expression Inventory entered the analyses. At a structural level, the concentration of grey matter in a network including ventromedial temporal areas, posterior cingulate, fusiform gyrus and cerebellum was associated with trait anger. The higher the concentration, the higher the proneness to experience anger in daily life due to the greater tendency to orient attention towards aversive events and interpret them with higher hostility. At a functional level, the activity of the default mode network (DMN) was associated with anger control. The higher the DMN temporal frequency, the stronger the exerted control over anger, thus extending previous evidence on the role of the DMN in regulating cognitive and emotional functions in the domain of anger. Taken together, these results show, for the first time, two specialized brain networks for encoding individual differences in trait anger and anger control.

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.

Trait self-control mediates the association between resting-state neural correlates and emotional well-being in late adolescence

Trait self-control (TSC), defined as the capacity to alter predominant response to promote desirable long-term goals, has been found to facilitate emotional well-being (EWB). However, the neural correlates underlying this association remain unclear. The present study estimated resting-state brain activity and connectivity with amplitude of low-frequency fluctuations (ALFFs) and resting-state functional connectivity (rsFC) among late adolescents. Whole-brain correlation analysis showed that higher TSC was associated with increased ALFFs in regions within the executive control network (inferior frontal gyrus, IFG) and the salience network (anterior insula, AI) and decreased ALFF in regions (e.g. medial frontal gyrus, MFG; posterior cingulate, PC) within the default-mode network (DMN). TSC was also linked with the integration (e.g. increased IFG-PC connectivity) and segregation (e.g. decreased AI-MFG connectivity) among brain networks. Mediation analysis indicated that TSC totally mediated the links from the IFG and the precuneus, FC of the AI and regions of the DMN (e.g. bilateral PC and MFG), to EWB. Additionally, ALFF in the IFG and the MFG could predict negative affect in the pandemic through TSC. These findings suggest that TSC is involved in several regions and functional organizations within and between brain networks and mediated the association between neural correlates and emotional wellness in adolescence.

The MAOA Gene Influences the Neural Response to Psychosocial Stress in the Human Brain

The stress response is regulated by many mechanisms. Monoamine oxidase A (MAOA) has been related to many mental illnesses. However, few studies have explored the relationship between MAOA and acute laboratory-induced psychosocial stress with functional magnetic resonance imaging (fMRI). In the current study, the Montreal Imaging Stress Task (MIST) and fMRI were used to investigate how MAOA influences the stress response. Increased cortisol concentrations were observed after the task; functional connectivity between the bilateral anterior hippocampus and other brain regions was reduced during stress. MAOA-H allele carriers showed greater deactivation of the right anterior hippocampus and greater cortisol response after stress than did MAOH-L allele carriers. Hippocampal deactivation may lead to disinhibition of the hypothalamic-pituitary-adrenal (HPA) axis and the initiation of stress hormone release under stress. Our results suggest that the MAOA gene regulates the stress response by influencing the right anterior hippocampus.

Effects of BDNF Val66Met polymorphisms on brain structures and behaviors in adolescents with conduct disorder

Accumulating evidence suggests that neural abnormalities in conduct disorder (CD) may be subject to genetic influences, but few imaging studies have taken genetic variants into consideration. The Val66Met polymorphism of brain-derived neurotrophic factor (BDNF) has emerged as a high-interest genetic variant due to its importance in cortical maturation, and several studies have implicated its involvement in neurodevelopmental disorders. Thus, it is unclear how this polymorphism may influence brain anatomy and aberrant behaviors in CD. A total of 65 male adolescents with CD and 69 gender-, IQ- and socioeconomic status-matched healthy controls (HCs) (age range 13-17 years) were enrolled in this study. Analyses of variance (ANOVAs) were used to assess the main effects of CD diagnosis, BDNF genotype, and diagnosis-genotype interactions on brain anatomy and behaviors. We detected a significant main effect of BDNF genotype on temporal gyrification and antisocial behaviors, but not on CD symptoms. Diagnosis-genotype interactive effects were found for cortical thickness of the superior temporal and adjacent areas. These results suggest that the BDNF Val66Met polymorphism may exert its influence both on neural alterations and delinquent behaviors in CD patients. This initial evidence highlights the importance of elucidating potentially different pathways between BDNF genotype and cortical alterations or delinquent behaviors in CD patients.

Exogenous testosterone and the monoamine-oxidase A polymorphism influence anger, aggression and neural responses to provocation in males

Testosterone and the monoamine oxidase-A (MAOA) polymorphism are potential neuromodulators for aggression. By acting on similar brain circuits, they might interactively influence human behavior. The current study investigates the causal role of testosterone on aggression-related brain activity and the potential interaction with the MAOA polymorphism. In a double-blind process, 93 healthy males received a testosterone or placebo gel. In an fMRI session, participants performed a Taylor aggression paradigm in which they received provoking feedback and could afterwards decide how aggressively they would react. Testosterone and cortisol levels as well as subjective anger were assessed prior and after the task. Circulating testosterone levels were higher in carriers of the long compared to the short MAOA allele. An interaction of the MAOA polymorphism and testosterone administration was identified in the cuneus, where short allele carriers in the placebo group showed diminished activity in the decision period. Task-related anger was significantly higher in this group. Overall, a mesocorticolimbic network was implicated in processing of high versus low provoking feedback, and core hubs of the default mode network were implicated in the subsequent decision after high versus low provocation. Testosterone administration increased activation in this network. The data provides evidence for an interaction of the MAOA polymorphism and exogenous testosterone on anger and suggests that interactive effects on the brain signal could underlie differential emotional reactivity. The increased default mode activation in the testosterone group suggests an enhanced engagement of social cognition related regions possibly supporting responsivity towards social provocation. This article is part of the Special Issue entitled 'Current status of the neurobiology of aggression and impulsivity'.