Aggressive Social Behavior Research Articles

Simple Behavioral Analysis (SimBA) as a platform for explainable machine learning in behavioral neuroscience.

The study of complex behaviors is often challenging when using manual annotation due to the absence of quantifiable behavioral definitions and the subjective nature of behavioral annotation. Integration of supervised machine learning approaches mitigates some of these issues through the inclusion of accessible and explainable model interpretation. To decrease barriers to access, and with an emphasis on accessible model explainability, we developed the open-source Simple Behavioral Analysis (SimBA) platform for behavioral neuroscientists. SimBA introduces several machine learning interpretability tools, including SHapley Additive exPlanation (SHAP) scores, that aid in creating explainable and transparent behavioral classifiers. Here we show how the addition of explainability metrics allows for quantifiable comparisons of aggressive social behavior across research groups and species, reconceptualizing behavior as a sharable reagent and providing an open-source framework. We provide an open-source, graphical user interface (GUI)-driven, well-documented package to facilitate the movement toward improved automation and sharing of behavioral classification tools across laboratories.

Chemical cousins with contrasting behavioural profiles: MDMA users and methamphetamine users differ in social-cognitive functions and aggression

Methamphetamine (METH, “Crystal Meth”) and 3,4-methylenedioxymethamphetamine (MDMA, “Ecstasy”) share structural-chemical similarities but have distinct psychotropic profiles due to specific neurochemical actions. Previous research has suggested that their impact on social cognitive functions and social behaviour may differ significantly, however, direct comparisons of METH and MDMA users regarding social cognition and interaction are lacking. Performances in cognitive and emotional empathy (Multifaceted Empathy Test) and emotion sensitivity (Face Morphing Task), as well as aggressive social behaviour (Competitive Reaction Time Task) were assessed in samples of n = 40 chronic METH users, n = 39 chronic MDMA users and n = 86 stimulant-naïve controls (total N = 165). Self-reports and hair samples were used to obtain subjective and objective estimates of substance use patterns. METH users displayed diminished cognitive and emotional empathy towards positive stimuli, elevated punitive social behaviour regardless of provocation, and self-reported heightened trait anger relative to controls. MDMA users diverged from the control group only by exhibiting a distinct rise in punitive behaviour when faced with provocation. Correlation analyses indicated that both higher hair concentrations of MDMA and METH may be associated with reduced cognitive empathy. Moreover, greater lifetime MDMA use correlated with increased punitive behaviour among MDMA users. Our findings confirm elevated aggression and empathy deficits in chronic METH users, while chronic MDMA users only displayed more impulsive aggression. Dose-response correlations indicate that some of these deficits might be a consequence of use. Specifically, the dopaminergic mechanism of METH might be responsible for social-cognitive deficits.

Sex Differences in Sociability for Drosophilamelanogaster with Altered Gut Microbiomes.

In Drosophila melanogaster the gut microbiome has been shown to influence multiple behaviors, including aggressive social behavior. Here, we investigate the effect of the Drosophila microbiome on pro-social behavior. We predicted that reducing the microbiome would lead to a decrease in pro-social behavior in adult flies. After altering the flies' microbiomes, we observed that virgin male flies with reduced microbiomes were significantly less social than virgin male control flies (t=3.09, p=0.006). We did not observe this difference in virgin female flies (t=0.344, p=0.73), or mated flies of either sex (males: t=0.456, p=0.66; females: t=0.271, p=0.79). Our results suggest that the role of the Drosophila microbiome in pro-social behavior is dependent on both sex and previous social experience.

The Effects of Ethanol and Acetic acid on Behaviour of Extranidal Workers of the Narrow-Headed Ant Formica exsecta (Hymenoptera, Formicidae) during a Field Experiment.

Ethanol addiction belongs to the most important problems encountered in the domain of human mental health. The research on the behavioural effects of exposure to/consumption of ethanol are investigated largely with the help of animal models that also include insects, mainly fruit flies and honeybees. The effects of ethanol on ant behaviour remain, however, little known. In the present field study, we investigated the behaviour of workers of the narrow-headed ant (Formica exsecta) displayed in the vicinity of cotton pads soaked in water or in water solutions of ethanol or acetic acid during 5 min tests (n = 30 tests in each group). Both ethanol and acetic acid induced significant modifications of ant locomotion, exploratory behaviour, self-grooming behaviour, and aggressive social behaviour. We confirmed that acetic acid is aversive for the ants, but ethanol enhances their exploratory behaviour. We also found out that field studies may document more types of responses to experimental compounds than laboratory ones, as the tested animals may also escape from aversive substances. Our findings documented a wide spectrum of behavioural effects of exposure to ethanol and acetic acid in a highly social animal species and broadened the general knowledge about behavioural responses to these compounds encountered in animals.

Influence of enrichment materials on the behaviour and productive traits of fattening pigs

In industrial complexes, the environment for fattening pigs has limited space and often does not respect natural behaviour of pigs. The implementation of EU legislation in Ukraine requires from farmers to use enrichment materials that improve the welfare of pigs. This article shows possible solution for big industrial challenge – creating of comfortable conditions for pigs, which meet their ethological needs. The experiment was performed on 180 pigs. From 77 days of age, all experimental animals were divided into three groups (on the principle of analogues) of 60 heads in each. As criteria of aggressive social behaviour the fights and biting were chosen. It was found that at the first period of fattening in pigs of the control group (no enrichment materials) 24 cases of biting were registered, in animals with straw blocks (experimental group II) – 6, with plastic bottles filled with grain (experimental group III) – 4 cases. At the second period of fattening, the situation regarding intragroup aggression was identical to the first one, which was reflected by the level of the cortisol in the blood serum. Among pigs that had free access to enrichment materials, a significant increase in their live weight by 2.4–5.8%, and in average daily gain by 1.4–27.6% compared with animals in the control group was registered. This study aims to prove that the use of enrichment materials for fattening pigs helps to identify their natural behaviour in industrial complexes, avoids social aggression, increases productivity and improves their welfare.

Aberrant aggressive behavior in a mouse model of Angelman syndrome

Angelman syndrome (AS) is a genetic neurodevelopmental disorder due to the absence of the E3-ligase protein, UBE3A. Inappropriate social interactions, usually hyper-sociability, is a part of that syndrome. In addition, clinical surveys and case reports describe aggressive behavior in AS individuals as a severe difficulty for caretakers. A mouse model for AS recapitulates most of the human AS phenotypes. However, very few studies utilized this mouse model for investigating affiliative social behavior, and not even a single study examined aggressive behavior. Hence, the aim of the herein study was to examine affiliative and aggressive social behavior. For that, we utilized a battery of behavioral paradigms, and performed detailed analyses of these behaviors. AS mice exhibited a unique characteristic of reduced habituation towards a social stimulus in comparison to their wild-type (WT) littermates. However, overall there were no additional marked differences in affiliative social behavior. In contrast to the mild changes in affiliative behavior, there was a striking enhanced aggression in the AS mice compared to their WT littermates. The herein findings emphasize the use of AS mouse model in characterizing and measuring inappropriate aggressive behavior, and suggests these as tools for investigating therapeutic interventions aimed at attenuating aggressive behavior.

Rage Against the Machine: Advancing the study of aggression ethology via machine learning.

Aggression, comorbid with neuropsychiatric disorders, exhibits with diverse clinical presentations and places a significant burden on patients, caregivers, and society. This diversity is observed because aggression is a complex behavior that can be ethologically demarcated as either appetitive (rewarding) or reactive (defensive), each with its own behavioral characteristics, functionality, and neural basis that may transition from adaptive to maladaptive depending on genetic and environmental factors. There has been a recent surge in the development of preclinical animal models for studying appetitive aggression-related behaviors and identifying the neural mechanisms guiding their progression and expression. However, adoption of these procedures is often impeded by the arduous task of manually scoring complex social interactions. Manual observations are generally susceptible to observer drift, long analysis times, and poor inter-rater reliability, and are further incompatible with the sampling frequencies required of modern neuroscience methods. In this review, we discuss recent advances in the preclinical study of appetitive aggression in mice, paired with our perspective on the potential for machine learning techniques in producing automated, robust scoring of aggressive social behavior. We discuss critical considerations for implementing valid computer classifications within behavioral pharmacological studies. Open-source automated classification platforms can match or exceed the performance of human observers while removing the confounds of observer drift, bias, and inter-rater reliability. Furthermore, unsupervised approaches can identify previously uncharacterized aggression-related behavioral repertoires in model species. Advances in open-source computational approaches hold promise for overcoming current manual annotation caveats while also introducing and generalizing computational neuroethology to the greater behavioral neuroscience community. We propose that currently available open-source approaches are sufficient for overcoming the main limitations preventing wide adoption of machine learning within the context of preclinical aggression behavioral research.

Environmental enrichment modulates affiliative and aggressive social behaviour in the neuroligin-3 R451C mouse model of autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterised by impairments in social communication and the presence of restrictive and repetitive behaviours. A mouse model expressing an autism-associated R451C mutation in the gene encoding the synaptic adhesion protein neuroligin-3 (NL3) has been extensively characterised and shows altered behaviour relevant to core traits observed in ASD. Reported impairments in social behaviours in NL3R451C mice however remain controversial due to inconsistent findings in various assays across different laboratories. Such inconsistencies could plausibly be explained by an increased susceptibility of the NL3R451C mouse social phenotype to environmental modulation. To address this, NL3R451C mice were housed in standard or enriched housing from 4 weeks of age prior to behavioural testing. Enrichment rearing enhanced direct interactions with the stranger mouse in all mice in the three-chamber social interaction test however, NL3R451C mice did not show impairment in social interaction in the three-chamber test, in contrast with previous reports. Environmental enrichment enhanced aggressive behaviour in all mice, and did not specifically alter the heightened aggressive phenotype previously described in NL3R451C mice. Specific genotype effects of enrichment included reduced anxiety-like behaviour in WT mice, and lower locomotor activity levels in NL3 mice. While genotype-specific effects of enrichment were not seen on social behaviour, the general increase in affiliative social interaction and aggression seen in all mice, indicates that these behaviours, are vulnerable to change based on housing condition. Mouse models expressing ASD-associated mutations have great utility in elucidating the neurobiology underling development of core traits and it is crucial that efforts are focussed on those models exhibiting robust phenotypes. In light of the findings in the present study, we suggest approaches to improve replicability and reproducibility in mouse models of ASD.

The Analysis of Temperature Changes of the Saliva Traces Left on the Fur During Laboratory Rats Soial Contacts.

Automatic analysis of complex rodent social behavior, especially aggressive ones, is of important scientific interest. In this paper we analyze the properties of the data created as a result of aggressive rodent social behavior. Detection of specific aggressive behaviors is based on the event of leaving traces of saliva on the fur of the attacked individual, which are clearly visible in the thermal imaging. The traces change temperature in time in a specific way. After bite, saliva is cooled and then heated to the body temperature. Usage of this method in social behavior analysis ensures detection and tracking aggressive behaviors even if the event itself is invisible.

A new model as an early life manipulation: Fake mother

IntroductionEarly life stressful events cause long-term neural changes that are associated with psychiatric disorders.ObjectiveEarly life manipulations focus on commonly the impact of remaining separate from the mother in a specific period of time. The maternal odor is required for pups to approach the mother for nursing. What happens when there is a mother that smell like a real mother but does not take care her own pups?AimTo investigate the fake mother effects on adult rat's behavioral changes, NMDR2B protein level changes in prefrontal cortex and hippocampus.MethodsWistar rats were used. Fake mother (n:13), early handling (n:12), maternal separation (n:14) and control (n:12) were the study groups. A fake mother is an object that smells like a real dam. When the real mother is separated from own pups fake mother stays with the pups for an hour. Manipulations were made during the postnatal first 14 days. Behavioral tests (social interaction test, elevated plus maze, novel object recognition test) were made between postnatal 62 and 78 days. NMDAR2B protein levels in prefrontal cortex and hippocampus were evaluated by using ELISA at postnatal 78 days.ResultsIn social interaction test, fake mother group exhibited less social behavior and more aggressive behavior than the other groups. Their long-term memory functions were the lowest. NMDAR2B protein levels in the hippocampus increased in rats that exposed to early stressful life events.ConclusionThese results support that being raised by fake mother increases aggressive behavior and decrease social behavior in adulthood.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Control your anger! The neural basis of aggression regulation in response to negative social feedback.

Negative social feedback often generates aggressive feelings and behavior. Prior studies have investigated the neural basis of negative social feedback, but the underlying neural mechanisms of aggression regulation following negative social feedback remain largely undiscovered. In the current study, participants viewed pictures of peers with feedback (positive, neutral or negative) to the participant's personal profile. Next, participants responded to the peer feedback by pressing a button, thereby producing a loud noise toward the peer, as an index of aggression. Behavioral analyses showed that negative feedback led to more aggression (longer noise blasts). Conjunction neuroimaging analyses revealed that both positive and negative feedback were associated with increased activity in the medial prefrontal cortex (PFC) and bilateral insula. In addition, more activation in the right dorsal lateral PFC (dlPFC) during negative feedback vs neutral feedback was associated with shorter noise blasts in response to negative social feedback, suggesting a potential role of dlPFC in aggression regulation, or top-down control over affective impulsive actions. This study demonstrates a role of the dlPFC in the regulation of aggressive social behavior.

Correlates of conflict, power and authority management, aggression and impulse control in the Jamaican population.

The object of this study is to establish the correlates of the phenomenology of conflict and power management in the Jamaican population. A total of 1506 adult individuals were sampled from 2150 households using a stratified sampling method and assessed using the 12 questions of the Jamaica Personality Disorder Inventory (JPDI) on the phenomenology of conflict and power management that are grouped into the psychological features of aggressive social behaviour, unlawful behaviour, socially unacceptable behaviour and financial transgressive behaviour. The database of responses to the demographic and JPDI questionnaires was created and analysed using the Statistical Package for the Social Sciences (SPSS) version 17. Of the national population sampled, 69.1% denied having any phenomenological symptoms of abnormal power management relations while 30.9% of the population admitted to having some degree of conflict and power management, ranging from mild (10.3%), to moderate (17.1), or severe (3.5%). There were 46.55% of the population which had problems with aggressive social behaviour, 9.33% had problems with unlawful behaviour, 9.58% had problems with unacceptable social behaviour and 37.74% had problems with financial transgressive behaviour. Significant gender and socio-economic class patterns for conflict and power management were revealed. This pattern of conflict and power management behaviour is critical in understanding the distinction between normal and abnormal expression of these emotions and actions. Nearly one-third of the sample population ` studied reported problems with conflict, abnormal power and authority management, impulse control and serious aggressive and transgressive behaviour.

Mild expression differences of MECP2 influencing aggressive social behavior

The X-chromosomal MECP2/Mecp2 gene encodes methyl-CpG-binding protein 2, a transcriptional activator and repressor regulating many other genes. We discovered in male FVB/N mice that mild (∼50%) transgenic overexpression of Mecp2 enhances aggression. Surprisingly, when the same transgene was expressed in C57BL/6N mice, transgenics showed reduced aggression and social interaction. This suggests that Mecp2 modulates aggressive social behavior. To test this hypothesis in humans, we performed a phenotype-based genetic association study (PGAS) in >1000 schizophrenic individuals. We found MECP2 SNPs rs2239464 (G/A) and rs2734647 (C/T; 3′UTR) associated with aggression, with the G and C carriers, respectively, being more aggressive. This finding was replicated in an independent schizophrenia cohort. Allele-specific MECP2mRNA expression differs in peripheral blood mononuclear cells by ∼50% (rs2734647: C > T). Notably, the brain-expressed, species-conserved miR-511 binds to MECP2 3′UTR only in T carriers, thereby suppressing gene expression. To conclude, subtle MECP2/Mecp2 expression alterations impact aggression. While the mouse data provides evidence of an interaction between genetic background and mild Mecp2 overexpression, the human data convey means by which genetic variation affects MECP2 expression and behavior.

P.1.g.036 Role of cannabinoid CB1 receptor in the regulation of aggressive social behaviour

P.1.g.036 Role of cannabinoid CB1 receptor in the regulation of aggressive social behaviour

Circadian Time Organization of Professional Firemen: Desynchronization—Tau Differing from 24.0 Hours—Documented by Longitudinal Self-assessment of 16 Variables

*This work is dedicated to the memories of Drs. Israel Ashkenazi and Erhard Haus, outstanding pioneers of medical chronobiology, dear colleagues, and distinguished gentlemen of exceptional human qualities.We investigated the circadian synchronization/desynchronization (by field-study assessment of differences in period, τ, of 16 coexisting and well-documented rhythms) of 30 healthy firemen (FM) exposed to irregular, difficult, and stressful nocturnal work hours who demonstrated excellent clinical tolerance (allochronism). Three groups of FM were studied (A = 12 FM on 24-h duty at the fire station; B = 9 FM on 24-h duty at the emergency call center; C = 9 day-shift administrative FM) of mostly comparable average age, body mass index, career duration, chronotype—morningness/eveningness, and trait of field dependence/independence. The self-assessed 16 circadian rhythms were (i) physiological ones of sleep-wake (sleep log), activity-rest (actography), body temperature (internal transmitter pill probe), right- and left-hand grip strength (hand dynamometer), systolic and diastolic blood pressure (BP) plus heart rate (ambulatory BP monitoring device); (ii) psychological ones (visual analog self-rating scales) of sleepiness, fatigue, fitness for work, and capacity to cope with aggressive social behavior; and (iii) cognitive ones of eye-hand skill and letter cancellation, entailing performance speed (tasks completed/unit time) and accuracy (errors). Data (4–6 time points/24 h; 2 591 480 values in total) were gathered continuously throughout two 8-d spans, one in winter 2010–2011 and one in summer 2011. Each of the resulting 938 unequal-interval time series was analyzed by a special power spectrum analysis to objectively determine the prominent τ. The desynchronization ratio (DR: number of study variables with τ = 24.0 h/number of study variables × 100) served to ascertain the strength/weakness of each rhythm per individual, group, and season. The field study confirmed, independent of group and season, coexistence of rather strong and weak circadian oscillators. Interindividual differences in DR were detected between groups and seasons (χ2, correlation tests, analysis of variance [ANOVA]). Moreover, in each group, both in winter and summer, a normal distribution was observed in the number of FM with rhythms with τ = 24.0 h, e.g., ranging from 5/16 (large desynchronization) to 16/16 (no desynchronization). Such a normal distribution with intraindividual stability over time (i.e., seasons) is consistent with the hypothesis of an inherited origin of a differential propensity to circadian desynchronization and which is supported by the distribution of τs in winter and summer following the Dian-Circadian Genetic Model, i.e., with τ = 24.0 h, τ = 24.0 h + n(0.8 h), and τ = 24.0 h − n(0.8 h).

Management of Zygomatic Complex Residual Deformity Due to War in Iraq

Since March 20, 2003, maxillofacial surgeons in Iraq encounter several trauma cases, part of which are zygomatic residual deformities that result from conventional war, civil unrest, crimes, and car explosions. This study aimed to determine the relationship between etiological factors and severity of posttraumatic zygomatic residual deformity and to investigate methods of surgical repairs, treatment modalities, and any complications that may have occurred during this critical time in Iraq. There were a total of 40 patients with posttraumatic deformity of the zygoma included in this study. Records of these patients (29 men and 11 women) who have been treated in the maxillofacial unit of a specialized surgery hospital (Medical City Hospital, Baghdad) between 2006 and 2011 were collected. Of all patients, 28 (70%) had injuries from missile whereas 12 patients (30%) had injuries from other causes (aggressive social behavior). According to the causes of delayed treatment, 30 patients (60%) were untreated previously (15 patients [50%] of them had delay because severe comminution, severe damage, or loss of the overlying soft tissue; 3 patients [10%] were undiagnosed; and 12 patients [40%] had treatment delayed as a result of major damage to other body parts or medical condition), 3 patients (30%) had improper reduction, and 7 patients (70%) had improper fixation. Our definitive treatment was as follows: 13 patients (32.5%) were treated by osteotomy, 10 patients (25%) were treated by onlay bone graft, 14 patients (35 %) were treated by both methods, and 3 patients (7.5%) were untreated. [corrected] We recommend that every surgeon who deals with residual deformity should clinically evaluate the residual deformity.

Predation Bite-Marks on a Peirosaurid Crocodyliform from the Upper Cretaceous of Neuquén Province, Argentina

Bite marks and injuries caused by intraspecific predation or aggressive social behavior are uncommon in fossil vertebrates, and in the fossil record of suchian archosaurs they are extremely unusual. A peirosaurid crocodyliform collected from the Upper Cretaceous beds of the Neuquén Group (northern Patagonia, Argentina) shows abundant bite marks and injuries. These injuries are spread across all the preserved parts of the specimen, with the highest concentration of bite marks, perforations and breakage in the caudal region. Characteristics of these injuries are analyzed, and their possible origin and related taphonomic aspects are assessed. Results indicate that the injuries were not produced by intraspecific fighting, but probably by the predating action of a theropod dinosaur.

Non-breeding territoriality in the New Holland Honeyeater, Phylidonyris novaehollandiae, in an unpredictable environment—short-term energy costs for possible long-term reproductive benefits

The short-term energetic and long-term reproductive costs and benefits of aggressive social behaviour of New Holland Honeyeaters were examined in an open forest where nectar availability for part of the year was highly unpredictable. Despite the variability in food supply, birds consistently maintained priority and, to varying degrees, exclusive access to certain areas. Feeding territories held between the autumn and spring breeding seasons did not always provide sufficient energy to cover the owner's daily costs of occupation. An indirect assessment of the net energy benefits revealed that owners may experience considerable periods of food shortage. Despite this, owners remained site faithful as the areas defended were all close to, or overlapped, sites used for nesting. These areas had a high density of both Banksia spp. (food plants) and Leptospermum spp. (nest plants). It appears that while non-breeding territories may be unprofitable in the short term, owners that maintain them benefit in the long term by ensuring access to nesting sites.

Individual aggressiveness measured in a resident-intruder test predicts the persistence of aggressive behaviour and weight gain of young pigs after mixing

Young growing pigs of both sexes housed in littermate groups of eight were given an aggressiveness score based on two resident-intruder tests. They were then mixed into new groups of eight, composed of four randomly selected pigs from each of two litters, and behaviour was observed for 2 days (days 1 and 2). Aggressive social behaviour at mixing was analysed using weight and aggressiveness score (at both the group and individual levels) as explanatory variates. On day 1: heavier pigs in each group were more involved in fighting, won more fights, and also initiated more brief aggressive acts (headknocks and bites). Bullying was more frequent in groups with higher aggressiveness scores, and aggressive pigs also initiated more headknocks. On day 2: pigs with high aggressiveness scores persisted in showing aggressive behaviour, initiating fights, headknocks and chases. Aggressiveness score was now also associated with fighting success (in addition to weight). On both days, pigs preferred to lie with littermates rather than unfamiliar pigs, although this preference was less marked on day 2. A stronger preference for littermates was shown in heavier groups. A greater number of skin lesions were recorded at the beginning of day 2 in groups containing heavier pigs and/or pigs with higher aggressiveness scores. Weight gain in the 5 days following mixing was lower in groups containing pigs with high aggressiveness scores. Overall, weight and aggressiveness score (measured in a resident-intruder test) each affected different aspects of aggressive behaviour at mixing. While weight predicted success in agonistic interactions, aggressiveness affected the nature and time scale of interaction: high aggressiveness score pigs showed more one-sided aggression (bullying) and their aggressive behaviour was more persistent, continuing into the day after mixing. Thus, aggression at mixing can be reduced by mixing smaller pigs, and identifying a means of reducing individual aggressiveness would be worthwhile.

Longitudinal study of early childhood injuries and acute illnesses in the offspring of adolescent mothers who were aggressive, withdrawn, or aggressive-withdrawn in childhood.

In a 15-year longitudinal study, the medical records of 94 children whose adolescent mothers had childhood histories of aggressive, withdrawn, aggressive-withdrawn, or normative (nondeviant) social behavior were examined. The children's annual rates of visits to the emergency room (ER) and to nonemergency medical facilities, post-ER hospitalizations, diagnoses of injuries, acute illness and infection, asthma, and emergency surgical consultations were examined between birth and 48 months of age. Group differences were found for the annual rate at which children were brought to the ER and for injury-related post-ER hospitalizations. Sons of women in the aggressive group and both sons and daughters of women in the aggressive-withdrawn group had elevated and distinctive profiles in respect to specific emergency diagnostic and treatment variables compared with children of women in the nondeviant group.