Significant Decrease In Aggression Research Articles

Stimulation of medial amygdala GABA neurons with kinetically different channelrhodopsins yields opposite behavioral outcomes.

The medial amygdala (MeA) receives pheromone information about conspecifics and has crucial functions in social behaviors. A previous study showed that activation of GABA neurons in the postero-dorsal MeA (MeApd) with channelrhodopsin-2H134R (ChR2) stimulates inter-male aggression. When performing these experiments using the faster channelrhodopsinH134R,E123T (ChETA), we find the opposite behavioral outcome. A systematic comparison between the two channelrhodopsin variants reveals that optogenetic activation of MeApd GABA neurons with ChETA suppresses aggression, whereas activation under ChR2 increases aggression. Although the mechanism for this paradoxical difference is not understood, we observe that activation of MeApd GABA neurons with ChR2 causes larger plateau depolarizations, smaller action potentials, and larger local inhibition than with ChETA. Thus, the channelrhodopsin variant used for invivo optogenetic experiments can radically influence the behavioral outcome. Future work should continue to study the role of specific sub-populations of MeApd GABA neurons in aggression control.

Thought Problems and Aggression Over Time Among Youth in Foster Care

BackgroundYouth in foster care may demonstrate high levels of aggression and thought problems. There is a growing trend to consider mental health symptoms of youth involved with the foster care system from a developmental trauma perspective.ObjectiveThe aim of this study was to test if trauma, race, age, and gender predicted variability in thought problems and aggression for youth in foster care.MethodThe sample (n = 303) included youth in out-of-home placements with a mean age of 14 years, a diverse racial demographic, and almost an equal percentage of males and females. Participants were assessed over three waves using a series of multilevel growth curve models.ResultsResults indicated significant decreases in thought problems and aggression and youth with higher levels of trauma reported higher initial levels and swifter decreases of both thought problems and aggression over time.ConclusionsWhile trauma was associated with aggression and thought problems, results found that youth demonstrated significant decreases in aggression and thought problems over time. A better understanding of the long-term effects of trauma on thought problems and aggression of youth in foster care is needed. While our findings suggest foster care may be protective in fostering resilience, additional research on the nature of potential positive effects of foster care on aggression and thought problems is suggested.

Reproductive males are effective at managing conflict in captive Sulawesi crested macaques (Macaca nigra).

Group size, density, and composition significantly influence the expression of agonism and, as demography is frequently manipulated in captivity, natural mechanisms of conflict management may be disrupted. Here, we examine how changes to the social and physical environment of a captive group of Sulawesi crested macaques, Macaca nigra, influenced mechanisms of conflict management. The initial group was comprised of females, juveniles, and castrated males; under a series of management interventions, the group was moved to a new enclosure, 75% of the castrated adult males were removed, 67% of the females were contracepted, a novel, intact male was introduced, and the group was allowed access to an outdoor enclosure. Despite a decreasing trend in aggression following the changes to the social group, we found no significant differences in aggression or intervention behavior in the 5-week periods immediately following changes to the social group, apart from a significant decrease in aggression following the introduction of the novel male. This decrease in the frequency of aggression was still evident 10 weeks after the interventions occurred, and was coupled with a decrease in the intensity of aggression. Moreover, the intensity of aggression as well as the frequency of aggression and intervention were significantly lower under low-density conditions. Our results highlight how management changes to the social and physical environment can influence aggressive behavior, albeit following a period of acclimation. We discuss the relative impacts of social group composition, social density, and individual reproductive status on the management of conflict behavior in a captive setting.

Reducing Aggression and Improving Physical Fitness in Adolescents Through an After-School Volleyball Program.

This study aimed to determine the effects of an after-school volleyball program on aggression and physical fitness in 14–16 years old students. One hundred and seven participants were randomized to a small-sided volleyball (SSV) training group or a control group (CON). The SSV group completed 8 months of small-sided volleyball training twice a week after school in addition to the regular physical education classes. Yo-Yo Intermittent Recovery Level 1 test (YYIRT1), medicine ball throw (MED), vertical jump (VJ), and Buss and Perry’s aggression questionnaire were evaluated before and after 8 months of training. Results revealed a significant interaction effect (group × time) in total sample for physical aggression [F(1, 105) = 17.688; p < 0.001], verbal aggression [F(1, 105) = 4.973; p = 0.028], anger [F(1, 105) = 7.662; p = 0.007], medicine ball throw [F(1, 105) = 36.143; p < 0.001], and YYIRT1 [F(1, 105) = 12.508; p = 0.001]. After-school small-sided volleyball for adolescents was accompanied by a significant decrease in aggression compared to physical education classes only. Additionally, adolescents from SSV group showed better results in physical fitness compared to the control group. Our findings significantly contribute to the understanding of possible mechanisms for reducing adolescents’ aggression, which include enjoyment, motivation, and self-control through sport intervention.

The Effect of Life Skills Training on Social and Coping Skills, and Aggression in High School Students

Background: Adolescence is known as a stressful period in the process of growth which they experience a lot of emotional, physical and cognitive changes at the same time. It is important to develop life skills in this age group. The goal of the study was whether life skills training affect the social and coping skills and aggression in high school students.Materials and Methods: A total of 100 high school students entered the study using a pretest-posttest assessment. All received life skills training (including coping skills, social skills and aggression control) during four sessions that each lasted 120 minutes. To compare the results before and after life skills training, four questionnaires including the individual characteristics of the study samples, the aggression test, the social skills test, and the coping skills checklist were used.Results: Life skills training had a positive and significant effect on social and coping skills. The results also showed there was a significant decrease in aggression among students.Conclusion: It is necessary to implement life skills training programs for a better and comprehensive development in students. Moreover, considering the formation of personality at an early age and the current situation of society, learning these skills at an early age seems more desirable.

Effects of neonatal handling on behavior and the stress response in rats selected for their reaction towards humans

It is known that neonatal handling may cause long-term changes in neurobiological and behavioral phenotypes. The neonatal handling of rats selected for enhanced aggressiveness towards humans (“aggressive” rats of generation 44) significantly mitigates aggression and stress responsiveness. However, the levels of corticosterone in stress in intact aggressive rats of later (70s) generations are lower than in generation 44, which differ little from the corresponding value in “tame” rats, selected in the opposite direction, for the absence of the aggressiveness towards humans. The goal of the present study is to find out whether the decrease in the stress response in aggressive rats at the current stage of selection is accompanied by a decrease in the influence of handling on aggressiveness. Experiments have been conducted with the Norway rat populations of the 75th generation of selection for aggressive and tame behavior, respectively. It has been found that the neonatal handling of aggressive animals causes a significant decrease in aggressiveness, albeit, considerably smaller than in generation 44. In both aggressive and tame rats, the blood corticosterone level under stress returns to the basal level for a longer time than in the corresponding control groups. Neonatal handling decreases the amount of mRNA for the glucocorticoid receptor (GR) in the hippocampus of aggressive rats but does not significantly affect the amount of mRNA for the corticotropin-releasing hormone (CRH) in the hypothalamus. However, in the control groups the level of CRH mRNA recorded in aggressive rats is higher than in tame ones. On the contrary, no differences in the GR mRNA are found between the strains, in contrast to earlier generations. It has been shown that the neonatal handling of pups is beneficial for maternal behavior in tame rats. Thus, the results obtained in generation 75 of selection indicate that the effect of handling on aggressiveness weakens with decreasing stress responsiveness in aggressive rats. This is likely to be related to the changing amount of GR in the hippocampus and stronger glucocorticoid-mediated feedback at the current stage of selection. The minor prolongation of the stress response appears to be related to the stressing component of neonatal handling rather than to changes in maternal care.

Effects of neonatal handling on behavior and stress-response in rats selected for reaction towards humans

It is known that neonatal handling may cause longterm changes in neurobiological and behavioral phenotypes. Neonatal handling of rats selected for enhanced aggressiveness towards humans (“aggressive” rats of generation 44) significantly mitigated aggression and stress responsiveness. However, levels of corticosterone in stress in intact aggressive rats of later generations (70s) were lower than in generation 44, which differed little from the corresponding value in “tame” rats, selected in the opposite direction, for the absence of aggressiveness towards humans. The study was conducted with Norway rat populations of the 75th generation of selection for aggressive and tame behavior, respectively. The goal was to find out whether the decrease in stress response in aggressive rats at the current stage of selection was accompanied by a decrease in the influence of handling on aggressiveness. It was found that neonatal handling of aggressive animals caused a significant decrease in aggressiveness, although considerably smaller than in generation 44. In both aggressive and tame rats, the blood corticosterone level at stress was getting back to the basal level for a longer time than in the corresponding control groups. Neonatal handling decreased the amount of mRNA for the glucocorticoid receptor (GR) in the hippocampus of aggressive rats but did not affect significantly the amount of mRNA for the corticotropin-releasing hormone (CRH) in the hypothalamus. However, higher contents of CRH mRNA were recorded in aggressive rats than in tame ones in the control groups. However, no differences in glucocorticoid receptor mRNA were found between the strains in contrast to earlier generations. It was shown that neonatal handling was beneficial for maternal behavior in tame rats. Thus, the results obtained in the 75th generation of selection indicate that the effect of handling on aggressiveness weakens with decreasing stress responsiveness in aggressive rats. This is likely to be related to the changing amount of GR in the hippocampus and stronger glucocorticoidmediated feedback at the current stage of selection. The minor prolongation of the stress response appears to be related to the stressing component of neonatal handling rather than to changes in maternal care.

Glucosinolate-derived isothiocyanates impact mitochondrial function in fungal cells and elicit an oxidative stress response necessary for growth recovery.

Glucosinolates are brassicaceous secondary metabolites that have long been considered as chemical shields against pathogen invasion. Isothiocyanates (ITCs), are glucosinolate-breakdown products that have negative effects on the growth of various fungal species. We explored the mechanism by which ITCs could cause fungal cell death using Alternaria brassicicola, a specialist Brassica pathogens, as model organism. Exposure of the fungus to ICTs led to a decreased oxygen consumption rate, intracellular accumulation of reactive oxygen species (ROS) and mitochondrial-membrane depolarization. We also found that two major regulators of the response to oxidative stress, i.e., the MAP kinase AbHog1 and the transcription factor AbAP1, were activated in the presence of ICTs. Once activated by ICT-derived ROS, AbAP1 was found to promote the expression of different oxidative-response genes. This response might play a significant role in the protection of the fungus against ICTs as mutants deficient in AbHog1 or AbAP1 were found to be hypersensitive to these metabolites. Moreover, the loss of these genes was accompanied by a significant decrease in aggressiveness on Brassica. We suggest that the robust protection response against ICT-derived oxidative stress might be a key adaptation mechanism for successful infection of host plants by Brassicaceae-specialist necrotrophs like A. brassicicola.

Správanie ošípaných pri vysokých teplotách ustajnenia

The effect of high temperature on the behaviour of growing-finishing pigs was studied. The pigs were housed in a climate controlled chamber, the air temperature was kept constant at 30°C and the relative humidity was 32.5% during the whole 3 months. Aggressive behaviour and daily activities of the pigs were recorded during the light hours, from 6:00 till 18:00. Detailed observations showed that during the experiment, the pigs were most of the time lying (72%, P<0.001). Pigs spent more time lying on the floor without bedding (86.65%, P<0.01) compared to floor with bedding (13.35%, P<0.001). The second activity, which occurred most after lying was eating (16%, P<0.001) then standing (10%, P<0.001). From all observation activities, the least amount of time the pigs were sitting (1%) and moving (1%). Drinking and social contacts – aggression were less frequent. After the each week, a significant decrease in aggression was recorded (P<0.001), an aggressive contacts occurred mainly during the eating and drinking. The pigs were active with peaks in the morning and afternoon. This study confirms that the high temperature influences the behaviour of the animals; the pigs are not very active, the most of the time they are lying on the cool places without bedding.

Adolescent anabolic/androgenic steroids: Aggression and anxiety during exposure predict behavioral responding during withdrawal in Syrian hamsters (Mesocricetus auratus)

In the U.S. and worldwide anabolic/androgenic steroid use remains high in the adolescent population. This is concerning given that anabolic/androgenic steroid use is associated with a higher incidence of aggressive behavior during exposure and anxiety during withdrawal. This study uses pubertal Syrian hamsters (Mesocricetus auratus) to investigate the hypothesis that an inverse behavioral relationship exists between anabolic/androgenic steroid-induced aggression and anxiety across adolescent exposure and withdrawal. In the first experiment, we examined aggression and anxiety during adolescent anabolic/androgenic steroid exposure and withdrawal. Adolescent anabolic/androgenic steroid administration produced significant increases in aggression and decreases in anxiety during the exposure period followed by significant decreases in aggression and increases in anxiety during anabolic/androgenic steroid withdrawal. In a second experiment, anabolic/androgenic steroid exposed animals were separated into groups based on their aggressive response during the exposure period and then tested for anxiety during exposure and then for both aggression and anxiety during withdrawal. Data were analyzed using a within-subjects repeated measures predictive analysis. Linear regression analysis revealed that the difference in aggressive responding between the anabolic/androgenic steroid exposure and withdrawal periods was a significant predictor of differences in anxiety for both days of testing. Moreover, the combined data suggest that the decrease in aggressive behavior from exposure to withdrawal predicts an increase in anxiety-like responding within these same animals during this time span. Together these findings indicate that early anabolic/androgenic steroid exposure has potent aggression- and anxiety-eliciting effects and that these behavioral changes occur alongside a predictive relationship that exists between these two behaviors over time.

Social skills training and parent education programs for aggressive preschoolers and their parents in South Korea

The purpose of this study was to develop and evaluate social skills training and parent education programs for aggressive young children and their parents in South Korea. Participants consisted of intervention group I, which included six children and their mothers in the social skills training and parent education programs; intervention group II, which included seven children and their mothers in the social skills training; and control group, which consisted of six children and their mothers. Pre-test–post-test control group design was used. Participants in both intervention groups reported a significant decrease in aggression and on improvement in pro-social behavior, emotional regulation, and social skills, while the control group reported an increase in aggressive behavior. Mothers in the intervention group I also reported an increase in warmth/acceptance. The findings indicate that both programs are highly effective in reducing aggressive behavior among young children and in fostering positive parenting behaviors.

Constraints and blocks to change and improvement on acute psychiatric wards – lessons from the City Nurses project

Recent years have seen sustained criticism and inspection of acute inpatient psychiatric wards, with the publication of reports and research leading to policy developments and a variety of efforts to improve perceived deficits. The City Nurses project seeks to reduce levels of conflict and containment on acute wards through the placement of expert nurses on wards to assist with the implementation of changes according to a working model of conflict and containment generation, based on previous research. Evaluation has shown significant decreases in aggression, absconding and self-harm by patients. However, in the course of working with the wards, various constraints and blocks to change have been identified and we describe these in detail in this paper. Analysis of the fieldwork diaries of the two City Nurses identified that change was hindered by limited staffing resources, problems with the physical environment and other resources, insufficient beds and the process of bed management, hierarchical ambiguity and multidisciplinary issues, the overdemanding role of the ward manager, and pervasive anxiety about the potential for serious untoward incidents and their implications for staff. We argue that sustained positive change in acute inpatient psychiatry requires these underlying structural issues to be both acknowledged and, if possible, resolved.

Recognition of Dominance in the Big-Clawed Snapping Shrimp (Alpheus Heterochaelis Say 1818) Part I: Individual or Group Recognition?

The snapping shrimp Alpheus heterochaelis uses its snapper claw to produce fast water jets in fights. Here we investigate whether these shrimp are able to recognise their opponents (individually or on a group level) in order to reduce fighting costs and risk of injury. Losers meeting familiar or unfamiliar winners differ from those meeting inexperienced opponents by showing immediate escapes after a contact as well as hardly any aggressive behaviours (e.g. water jets). There is a significant decrease in aggressiveness in these losers and this is maintained for days. In contrast, losers meeting inexperienced opponents show a slow stepwise decrease in aggressiveness after losing on several consecutive days. Thus, snapping shrimp can recognise the dominance status of the opponent. The lack of behavioural differences in losers meeting familiar or unfamiliar winners favours recognition on a group level rather than individual recognition.

Compliance training decreases maladaptive behaviors in two people with developmental disabilities: report of five years' treatment

Compliance training was implemented to decrease non-compliance and avoidance behaviors in two women with severe mental retardation and psychiatric disorders over a five year period. In addition to compliance training, reinforcement schedules and behavioral momentum procedures were also included at various times. The program included training staff at home and at work to ensure generalization across settings and times, direct contact staff were used to assist in implementing compliance procedures at home and vocational trainers were used in the work setting. During baseline, Vanessa had pervasive non-compliant behaviors. Five years later, her non-compliance episodes had decreased by 89%. There were also significant decreases in aggression, self-abusive behaviors, and duration of non-compliance episodes. There were increases in interaction, productivity work, and reduced use of restraint. Annette was a woman with Generalized Anxiety Disorder with panic attacks. She had not left the home for several years. Once anxiety and panic attacks were under control maladaptive behaviors, which formerly functioned to avoid anxiety provoking situations, took on a different function, namely avoidance of work demands. Compliance training resulted in a reduction in non-compliance of 40–80% over a five year period. As a result psychoactive medication and restraint have been reduced and staff interaction and participation in campus and community activities have increased. © 1997 John Wiley & Sons, Ltd.

Corpus callosotomy in treatment of medically resistant epilepsy: preliminary results in a pediatric population.

We report the results of 34 patients who underwent corpus callosotomy between 1986 and 1989 with 28-65 months of postoperative follow-up (mean 42 months). Thirty-two patients had mental retardation and 26 had significant behavioral problems. Thirteen patients had total section, 8 had subtotal section with preservation of the posterior half of the splenium, and 13 had section of the anterior two thirds of the callosum. Satisfactory seizure control was achieved in 25 patients (73.5%) Atonic seizures, followed by tonic seizures, generalized tonic-clonic seizures (GTCs), and atypical absence seizures were most improved. Myoclonic and complex partial seizures (CPS) did not improve significantly. No deterioration in seizure status was observed postoperatively. Two patients developed previously unobserved simple seizures and CPS postoperatively, but they were not as disabling as the preoperative seizures. Among the patients with behavioral problems, 81% had significant decrease in aggressiveness, hyperactivity, and/or attention deficit. Patients who underwent total section had interhemispheric disconnection symptoms that improved progressively and did not interfere with daily life. Decreased speech output, dysarthria, and gait dyspraxia occurred after total callosal section and persisted in 5 of the 13 patients. Patients who underwent anterior two thirds or subtotal sections did not have such symptoms. Early postoperative complications consisted of aseptic ventriculitis (5), subdural hematoma (1), and wound infection (4) and resolved without sequelae.

Social isolation, aggression, and dominance in attacks in juvenile angelfish,Pterophyllum scalare

The effects of social isolation on aggressive behavior and rank order have been investigated in small groups of juvenile angelfish, Pterophyllum scalare. An experimental protocol including a “double transfer” of the subjects was used, in which fish were transferred to new aquaria in groups, before subsequent isolation and regrouping. A significant decrease in aggression was observed in the first recording session following both isolation and group transfer, after which the level returned to that recorded in the home tanks. The social hierarchy was also perturbed, but changes generally involed the two highest ranking fish in two out of the three groups, and were found not to be statistically significant. The behavior patterns are interpreted as adaptive responses to environmental change. © 1993 Wiley-Liss, Inc.

Program report: “time‐in”: A two‐year project for the reduction of severe maladaptive behaviors in a center for persons with developmental disabilities

AbstractThe results of a two‐year project designed to organize a unit for 18 developmentally disabled clients with severe behavior disorders (primarily aggression) were presented. Providing tightly organized structure and focusing on appropriate resident behavior resulted in substantial gains. Noted changes included significant decreases in aggression, total number of target behaviors, required uses of restrictive procedures, and residents' injuries. Decreases were also noted in staff injuries and turnover. Subjectively, the unit became a better place to work and live. Difficulties encountered with developing, maintaining, and generalizing the project were discussed.

Behaviour and distribution of fattening pigs in the multi-activity pen

Five groups of fattening pigs were observed in an experimental multi-activity pen with environmental enrichment. The pen measuring 36 m 2 included sections containing straw, feed and water connected by two corridors. In addition the pigs had access to straw racks, a shower and biting/levering logs. Social behaviour and spatial distribution of the pigs in the pen sections were recorded as well as the diurnal rhythm of the use of feeders, drinkers and shower. Furthermore, the defecation sites of the pigs were recorded. After the first three trials with 8, 16 and 24 pigs respectively, the pen was supplied with feed trough partitions, straw racks and biting/levering logs. After these changes, two more trials with 24 and 29 pigs, respectively, were tested. During light hours, the pigs were most often observed in the straw and feeder sections. By increasing group size/density, sniffing pen mate decreased ( P < 0.01), aggression increased ( P < 0.01) and nose to ano-genital increased ( P < 0.05). After the alteration of the pen, a significant decrease in aggression was recorded ( P < 0.001). Sniffing pen mate, aggression and non-aggressive biting was significantly influenced by the different environment. Most sniffing pen mate was recorded in the water section and the east corridor and most aggression was recorded in the feeder and water sections. Non-aggressive biting was mainly recorded in the straw section and the east corridor. Clinical signs of tail biting were never observed. The pigs were active at feeders, drinkers and shower mainly during the light hours and the activities were clearly bimodal with peaks in the morning and afternoon. The pigs kept the straw and feeder sections free from defecation, which mainly took place in the water section and the corridors close to the water section.

A positive approach to the treatment of aggressive brain injured clients

A broad spectrum behavior therapy approach was used to treat physical aggression in five brain injured clients. The approach employed high density reinforcement, reinforcer sampling, environmental control, selection of appropriate responses, inconvenience review, self-control training and self-monitoring. All five clients showed significant decreases in aggression immediately after the implementation of the program.

Social behaviors, social‐cognitive skills, and clinicians’ judgments of children referred for aggression

Aggressive, affiliative, and play interactions for a group of clinic‐referred aggressive 6‐year‐olds (n = 11) were observed over a six week social‐cognitive training program. Freeplay data showed significant decreases in aggression and significant increases in affiliation and associative play. Aggressive behaviors were structured into a dominance hierarchy before affiliative relations were established; however, the hierarchy's function in regulating aggression contrasted with reports of non‐clinic samples. Behavioral data, clinical judgments, and children's performance on social‐cognitive tasks provided concurrent social skill validity assessments. Clinicians’ assessments of children's social competence were significantly associated with changes in social play behaviors. Whereas children improved significantly on a number of social cognitive tasks, only their self‐concept scores correlated significantly with pro‐social behavior changes. Results demonstrate a useful within‐group method for monitoring socia...