Individual differences in chronically defeated male mice: behavioral, endocrine, immune, and neurotrophic changes as markers of vulnerability to the effects of stress

This study aimed to analyze different behavioral profiles in response to chronic social defeat using the sensorial contact model. We hypothesized that a passive profile, unlike an active one, would be associated with behavioral and physiological characteristics related to depression. Six-week-old OF1 male mice were subjected to defeat for 21 consecutive days. A combination of cluster and discriminant analyses of the behavior exhibited during confrontation on Day 21 established two behavioral profiles: active (n?=?22) and passive (n?=?34). Passive mice, with a high level of immobility and low non-social exploration, had higher plasma corticosterone concentrations than active mice after 21 days of defeat. Three days after the last defeat, passive mice had lower corticosterone levels than manipulated-control mice (n?=?11). Higher levels of interleukin-6 and tumor necrosis factor-α (TNF-α) in the spleen and lower hippocampal brain-derived neurotrophic factor levels were observed in passive mice in comparison with those in active mice and the manipulated controls. The only differences observed in active mice in relation to the manipulated control were higher plasma corticosterone (Day 21) and TNF-α levels. The results show that different behavioral profiles in response to chronic defeat are associated with different physiological profiles, and that the passive profile presents physiological characteristics previously associated with depression.     

Fighting experiences and natural killer cell activity in male laboratory mice

There is currently much interest in the potential impact of psychological factors on immune responses. An attempt was made to assess the effects of dominant/subordinate polarity in male mice on the cytotoxic activities of their natural-killer (NK) cells. On the basis of repeated agonistic encounters, categories of subordinate and dominat animals were selected. These animals were compared with manipulated controls (introduced to a novel test cage without an opponent on each occasion) and undisturbed controls (who remained in isolation without manipulation). In terms of NK activity, immunosuppression was observed in both dominant and subordinate categories when compared to undisturbed controls. There were, however, no differences between the fighting exposed subjects and the manipulated controls, suggesting that stress accounts for any changes. © 1994 Wiley-Liss, Inc.     

Learned Helplessness or Learned Inactivity after Inescapable Stress? Interpretation Depends on Coping Styles

Researches on uncontrollable events in the post-soviet states are overviewed. In our research, susceptibility to learned helplessness is studied in rats with active (KHA strain) versus passive (KLA strain) coping styles. Inescapable footshocks, but not escapable footshocks, applied to KHA rats induced escape failures, diminished locomotion and coping, reduced measures of anxiety, and resulted in dexamethasone nonsuppression of the brain-hypothalamus-pituitary-adrenal axis--all characteristic of learned helplessness. In contrast, KLA rats demonstrated the same responses upon exposure to both escapable and inescapable stresses. While learned helplessness occurred in KHA rats, it appears that KLA rats exposed to inescapable stress demonstrated learned inactivity based upon the nondifference between effects of escapable and inescapable shocks. Relationships between coping styles and social ranks are discussed. Our and other's results with genetically selected strains suggest active coping in dominant and subordinate subjects, and passive coping in subdominant animals confirm the importance of coping style and its relation to health under stress.     

Effects of stress on defensive aggression and dominance in a water competition test

Water-deprived rats in a pair competing for a single source of water quickly establish a firm relationship during which one rat drinks consistently more (dominant) than the other (submissive) animal. This relationship is formed during the first competition and is very stable during subsequent tests. Exposure of dominant rats to a severe (18 hrs immobilization), but not a mild (2 hrs immobilization), stressor reduced markedly aggressive behavior and inverted transiently the dominant submissive relationship of the pairs. Exposure of submissive rats to the severe stressor resulted in only minor reductions of aggressive behavior in these animals. Prestress anxiety predicted stress effects in the dominant animals in that high-anxious animals lost more dominant behavior and weight during stress as compared with low-anxious rats. Thus, severe stress can transiently reduce dominant but not submissive behavior during water competition and high-anxious rats are more prone to lose their aggressive behavior.     

Maternal Life Stress and Subsequent Chinese Toddlers’ Social Adjustment: The Moderating Role of Inhibitory Control

The current study examined the links between maternal life stress and subsequent toddler behavior problems and social competence, as well as the potential moderating effects of cool and hot inhibitory control (IC) in mainland China. Participants included 89 mothers and their infants (42 boys, 47 girls). Mothers completed self-report measure of maternal life stress when their children were 1 year of age (M?=?1.18, SD?=?.07 at Time 1), and reported on their children’s social adjustment using the Chinese version of Infant-Toddler Social and Emotional Assessment (CITSEA) at Time 1 and again a year later (M?=?2.06, SD?=?.09 at Time 2). Toddler IC was assessed with laboratory tasks at Time 2. Structural equation modeling with a bootstrap resample of 1000 indicated that cool IC significantly moderated the longitudinal association between maternal life stress (T1) and latent construct of toddler behavior problems (T2), controlling for behavior problems at Time 1, child age and maternal age. Specifically, maternal life stress was associated with subsequent behavior problems only for toddlers who were low in cool IC. In comparison to the results of behavior problems, high levels of maternal life stress predicted subsequent low levels of social competence. Neither cool IC nor hot IC served as the moderator in the association between maternal life stress (T1) and toddler social competence (T2). These findings indicated that toddler cool IC may promote resilient adaptation and modify the links between maternal life stress and toddler behavior problems but not social competence.     

What do you do when you're happy or blue? Mood,expectancies, and behavioral interest

The effects of induced moods on interest in performing a wide spectrum of behaviors were examined in two experiments. In Experiment 1, subjects who received the Velten Mood Induction elation manipulation indicated significantly greater interest than neutral subjects in social, prosocial, strenuous, leisure, and general activities on a shortened version of the Pleasant Events Schedule. Subjects who received the depression induction indicated lower interest in social, leisure, and strenuous activities. Depressed mood was associated with an interest in sitting and thinking, being alone, and taking a nap, but depression produced no increase in interest in prosocial behavior or in 12 forms of self-gratification. Experiment 2 focused on seven potential mediators in the effects of mood on behavior interests. Following a positive, negative, or neutral mood induction, subjects were asked to record their positive and negative outcome expectancies, positive and negative emotion expectancies, and their self-perceptions of energy, ability, and opportunity for active and passive, social and nonsocial behaviors. Induced elation, depression, and neutral moods again were found to influence interest in both active and passive types of social and nonsocial behaviors. The subjects' expectations of positive outcomes, and to a lesser extent their perceived energy for the behavior, were the strongest mediators of the effect of mood on behavior interests.The present experiments were conducted at Elmhurst College; thanks to Cindy Argianis, Chris Jankowski, and Victoria Mandell for their work in Experiment 1, and to Russell Fett for his help in Experiment 2. Valuable comments on an earlier draft were provided by Henry Adams, Anita Barbee, Katherine Noll, Sid Rosen, and David Shaffer.     

Learned helplessness or learned inactivity after inescapable stress? Interpretation depends on coping styles

Researches on uncontrollable events in the post-soviet states are overviewed. In our research, susceptibility to learned helplessness is studied in rats with active (KHA strain) versus passive (KLA strain) coping styles. Inescapable footshocks, butnot escapable footshocks, applied to KHA rats induced escape failures, diminished locomotion and coping, reduced measures of anxiety, and resulted in dexamethasone nonsuppression of the brain-hypothalamus-pituitary-adrenal axis—all characteristic of learned helplessness. In contrast, KLA rats demonstrated the same responses upon exposure to both escapable and inescapable stresses. While learned helplessness occurred in KHA rats, it appears that KLA rats exposed to inescapable stress demonstrated learned inactivity based upon the nondifference between effects of escapable and inescapable shocks. Relationships between coping styles and social ranks are discussed. Our and other’s results with genetically selected strains suggest active coping in dominant and subordinate subjects, and passive coping in subdominant animals confirm the importance of coping style and its relation to health under stress.     

后疫情时代：复工阶段不同阶层的社会情绪及压力因素

本研究考察新冠肺炎疫情复工阶段,不同阶层社会情绪和压力因素随时间的变化规律。基于三次问卷调查（NT1 = 1073; NT1 = 983; NT3 =1078）发现：（1）民众社会情绪均表现为积极情绪高于消极情绪,而且随时间推进社会情绪持续向好;（2）低阶层者的社会情绪始终比高阶层者更消极;（3）民众感知的安全压力随时间下降,而经济压力随时间没有显著变化;（4）低阶层者感知到更大的经济压力,高阶层者感知到更大的安全压力;（5）安全压力在社会阶层与积极情绪和消极情绪之间起显著的中介作用,经济压力在社会阶层与消极情绪之间起显著的中介作用。研究揭示了不同社会阶层在复工阶段存在社会情绪和压力来源的差异,为有针对性进行积极社会心态治理提供启示。     

The effect of sensory deprivation and ego strength on a measure of autistic thinking

In an experiment designed to test aspects of the psychoanalytic theory of ego functioning, 18 male and 18 female subjects were assigned in equal numbers to a 3 1/2-hr period of either sensory deprivation (SD), social isolation (SI) or social participation (SP). Their level of autistic thinking was assessed by a word-association measure administered immediately before and immediately after the treatment condition to which each subject had been assigned. Results showed that subjects assigned to SD showed an increase in autistic thinking scores from pretreatment to posttreatment, whereas subjects assigned to the two control conditions (SI and SP) showed a decrease. Although Minnesota Multiphasic Personality Inventory (MMPI) ego strength (Es) scores correlated negatively with the initial level of autistic thinking in all subjects, the experimental and control conditions had their greatest impact on subjects who scored low in Es. Results were interpreted as supporting the hypothesis that consensual functioning (particularly for subjects who scored low on Es) depends on continuing contact with reality.     

The role of neuropeptide Y in the amygdala on corticotropin-releasing factor receptor-mediated behavioral stress responses in the rat

Neuropeptide Y (NPY) is one of the most abundant peptides in the brain and has been shown to be a critical regulator of emotionality, most notably for its effect in decreasing anxiety-like behaviors. The stress response in both humans and animals has been shown to involve a cascade of biological events initiated by corticotropin releasing factor (CRF), another centrally acting peptide. Interestingly, NPY and CRF are present in similar brain regions mediating stress responses and may act in an opposing fashion. The basolateral nucleus of the amygdala (BLA) is a distinct division of the amygdala and contains CRF receptors and the highest concentration of NPY neurons. The current study investigates the behavioral effects in rodents when NPY is injected directly into the BLA prior to the pharmacological stressor, urocortin I (Ucn; a CRF receptor agonist) or the emotional stressor, restraint. The animals that underwent restraint were evaluated in the social interaction (SI) test, while those injected with Ucn into the BLA were assessed in the two floor choice test, a modified version of the conditioned-place avoidance paradigm. The results showed that injections of NPY into the BLA prior to Ucn significantly blocked the development of the avoidance behavior in the two floor choice test and the decrease in SI time that is usually seen following restraint stress. These results provide further support that an interaction between NPY and CRF within the BLA may be critical for maintaining a normal homeostatic emotional state.     

Anabolic-androgenic steroids: effects on social behavior and baseline heart rate

Examined the effects of anabolic-androgenic steroids (AS) on behavior, baseline heart rate (HR), and stress-induced HR responses. Twenty-four cynomolgus monkeys were assigned to four mixed social groups of both AS and sham control animals. For 2 months, AS-treated monkeys received biweekly injections of testosterone, and, on an identical schedule, the control animals were injected with a sham solution. Behavioral data revealed that AS disrupted the social milieu such that all dominant animals exhibited increases in dominant behavior and subordinates manifested increased submission. These changes returned to pretest levels 8 weeks following termination of the drug intervention. Affiliative behaviors decreased on the part of all animals as a function of AS and, with the exception of play behavior, failed to return to pretest levels after the 8-week period of recovery. AS created an increase in baseline HR, particularly among the dominant animals. Interestingly, the subordinate AS animals experienced a decrease in baseline HR response. AS had no apparent influence on stress-induced HR reactivity.     

Poor social performance of lonely people: lacking a skill or adopting a role?

A substantial literature has shown that lonely people differ from nonlonely people on a variety of measures of social performance. These differences have usually been conceptualized as a social skills deficit, which implies that lonely people lack the ability to perform appropriate and effective social behavior. Rather than a lack of this ability, the authors hypothesize that the adoption of passive interpersonal roles predisposes lonely people to exhibit inadequate performance. In order to test this hypothesis, lonely and nonlonely subjects were assigned to one of two roles: They either listened (Condition Li) to an interaction partner describe a personal problem or they themselves described a personal problem (Condition Pr) to their partner. The subjects' interpersonal role produced a substantial effect on their social behavior. Subjects who listened to their partner describe a problem generated more solutions to a set of hypothetical situations, attended to their partners more adequately, and conversed longer than did subjects who described a personal problem. In contrast, lonely subjects did not differ from nonlonely subjects in their social performance within each particular role. Lonely and nonlonely subjects did differ, however, in their subjective evaluations of themselves and of their performance. These results illustrate the need for research to address both the interpersonal and the intrapersonal bases of social performance.     

Attack-target attributes and pigeon aggression: Accessibility,vocalization, and body movements

Characteristics of the attack-target in laboratory tests appear to greatly influence the tendency for aggression to be initiated, maintained, and stopped. To address this question, accessibility, target movement, and vocalization among pigeon conspecifics were investigated in two different aggression tests: 1) paired aggression (PA); and 2) schedule-induced aggression (SI). In the PA test, dominant and subordinate roles formed quickly, and soon aggression episodes started to decline. In part, the subordinate's yielding behavior appeared to discourage attack. The significance of the target bird's behavior on attack frequency was borne out by the finding in the SI test that pigeons attacked a shielded, live, active target more often than a passive one. Furthermore, using a specially constructed stuffed pigeon in the SI test, results indicated that programmed, combined aggressive vocalization and body movement evoked most attacks with the VT schedule, vocalization alone evoked the next highest number of attacks, body movement alone the third most, and combined silence and immobility the least attacks. These findings provide a basis for explaining some past reported results associated with target features and a means for selecting other target features for future study.     

Seventh-day Adventist Clergy: Understanding Stressors and Coping Mechanisms

This article examines the extent and types of clergy stress, the strategies used in coping with stressors, and the relationship between stressors and coping mechanisms in a sample of 261 Seventh-day Adventist pastors in North America. The results indicate that the most commonly reported stressors in order are: (1) lack of social support, (2) financial stress, and (3) time and workload stress. In terms of coping strategies, pastors sought relief most often through: (1) reflective growth/internal change; (2) social/emotional coping; (3) passive coping; and lastly (4) action-oriented coping. Significant correlational relationships existed between passive coping and financial stress, relocating stress, and congregational stress. In addition, we found significant inverse correlations between coping through reflective growth or internal change and relocating stress and congregational stress. There were no significant relationships with action coping or social/emotional coping and any stressor. Multi-regression analysis reveals that passive coping strategies were significantly related to financial stress. Thus, the greater the financial stress, the more likely pastors were to engage in passive coping strategies. Other coping strategies showed no significant relationships when included in multi-regression analysis. We conclude with recommendations for Church administrators to address structures and practices in place for pastors including an expansion of coping mechanisms to help pastors address their stress.     

Immigration, suicidal ideation and deliberate self-injury in the Boston youth survey 2006

The prevalence and immigration-related correlates of deliberate self-injury (DSI) and suicidal ideation (SI) were estimated in a sample of Boston public high school students in 2006. Compared with U.S.-born youth, immigrant youth were not at increased risk for DSI or SI, even if they had experienced discrimination due to their ancestry. By contrast, U.S.-born youth who reported having been discriminated against because of their ancestry had an increased risk of deliberate self-injury (odds ratio [OR] = 3.1, 95% confidence interval [CI] = 1.6-5.9) and suicidal ideation (OR = 2.1, 95% CI = 1.2-3.8). The combination of being U.S.-born and experiencing ancestry-based discrimination identifies youth at increased risk for suicidal behavior.     

The Effect of Sensory Deprivation and Ego Strength on a Measure of Autistic Thinking

In an experiment designed to test aspects of the psychoanalytic theory of ego functioning, 18 male and 18 female subjects were assigned in equal numbers to a 3%-hr period of either sensory deprivation (SD), social isolation (SI) or social participation (SP). Their level of autistic thinking was assessed by a word-association measure administered immediately before and immediately after the treatment condition to which each subject had been assigned. Results showed that subjects assigned to SD showed an increase in autistic thinking scores from pretreatment to posttreatment, whereas subjects assigned to the two control conditions (SI and SP) showed a decrease. Although Minnesota Multiphasic Personality Inventory (MMPI) ego strength (Es) scores correlated negatively with the initial level of autistic thinking in all subjects, the experimental and control conditions had their greatest impact on subjects who scored low in Es. Results were interpreted as supporting the hypothesis that consensual functioning (particularly for subjects who scored low on Es) depends on continuing contact with reality.     

儿童同伴关系对孤独感的影响

以571名小学三、四、五、六年级的儿童为被试,考察了儿童社会喜好、友谊质量、消极退缩、社交自我知觉与孤独感的关系,检验了不同水平同伴关系变量对孤独感的影响。结果表明,儿童的同伴关系(同伴接纳、友谊质量、社交自我知觉)能显著预测其孤独感体验,其中,处于同伴关系个体水平的社交自我知觉对孤独感的预测作用最大,其次分别为双向关系水平的友谊质量和群体接纳水平的同伴接纳,而处于人际交互水平的消极退缩在控制了其他水平同伴关系变量的影响下,并不能显著预测其孤独感体验。     

Variation in aggressive behavior and anatomo-physiological correlates generated by crowding without physical contact in the house mouse

Behavioral, physiological (i.e., endocrine), and anatomical consequences of crowding in mice were studied in a situation where animals were in auditory, visual, olfactory, and tactile contact but restrained from full physical interactions, to prevent overt aggression. Males that cohabited with females undisturbed by neighboring conspecifics showed greater propensity to attack same-sex intruders and had higher plasma testosterone levels than did their “crowded” counterparts, that is, males cohabiting with females and housed adjacent to other male/female pairs. In this respect, the latter animals resembled submissive males. However, a significant increase in weight of androgen-dependent target organs (i.e., seminal vesicles and preputial glands) was found in crowded males. These data indicate that despite the observed inhibition of social aggression these males are not physiologically comparable (homologous) to male mice that experienced defeat and the stress of submission during fighting. The intriguing possibility that different conversion pathway of testosterone are accelerated, as a result of social communication, in males living in these two environments and the behavioral implications of these possibilities are discussed. Finally, the parental behavior of crowded animals, although not freely interacting with each other, was disrupted, causing a marked decrease in reproductive success. In this situation a high incidence of infanticide of their offspring by both parents was observed, whereas this behavior was virtually absent in non-crowded male/female pairs.     

Intrasexual interactions among female golden hamsters (Mesocricetus auratus) over the estrous cycle

Social interactions of cycling female golden hamsters paired with ovariectomized animals in large enclosures were primarily agonistic over the 4-day estrous cycle. These aggressive interactions were intense as indicated by frequent occurrences of chase and flight behavior. Dominant and subordinate social ranks were established in the majority of pairs (96%) tested, and even females in sexual heat were capable of attacking and dominating their rivals. Furthermore, cycling females exhibited significantly more aggressive acts than ovariectomized opponents 1 day prior to sexual receptivity. No differences in fighting patterns were found between animals on the other 3 days of the estrous cycle. Additional analyses revealed clear differences in agonistic elements, including flank marking, between dominant and subordinate females regardless of whether they were gonadectomized or intact. These analyses also showed that dominant individuals frequently chased and bit opponents during encounters within their nesting area. The data are examined for implications on the adaptive organization of female hamster agonistic behavior and the neuroendocrine regulation of species-typical behavior over the estrous cycle.     

Behavioral effects of testosterone in relation to social rank in the male rabbit

The role of gonadal androgens in favoring the adaptation to environmental pressure, including social organization, is well known. In the rabbit, testosterone administration increases marking behavior, and its level can be affected by agonistic interaction. In this experiment, we studied the effect of subcutaneous administration of testosterone propionate (TP) (3 mg/d for 6 days) in male rabbits belonging to the same social group (6 groups of 4 animals). In 2 additional groups (4 animals each), males were injected with almond oil. The animals were observed for 6 days in seminatural conditions, then treated with TP (or oil) and observed for another 6 days. The dominant/subordinate frequency ratio of behavioral patterns was used to rank the animals. The testosterone plasma concentration was correlated with agonistic behavior after the first period of social interaction. A significant increase of marking, digging, and defensive activity was observed after TP administration in all animals independent of rank, whereas this increase was not present in animals treated with oil. Agonistic and interactive behaviors increased significantly after TP treatment only in the first‐ranking animals. This indicates the influence of social rank in the modification of behaviors involving interactions among subjects Aggr. Behav. 29:269–278, 2003. © 2003 Wiley‐Liss, Inc.