Stress modulation of cognitive and affective processes

This review summarizes the major discussion points of a symposium on stress modulation of cognitive and affective processes, which was held during the 2010 workshop on the neurobiology of stress (Boulder, CO, USA). The four discussants addressed a number of specific cognitive and affective factors that are modulated by exposure to acute or repeated stress. Dr David Morilak discussed the effects of various repeated stress situations on cognitive flexibility, as assessed with a rodent model of attentional set-shifting task, and how performance on slightly different aspects of this test is modulated by different prefrontal regions through monoaminergic neurotransmission. Dr Serge Campeau summarized the findings of several studies exploring a number of factors and brain regions that regulate habituation of various autonomic and neuroendocrine responses to repeated audiogenic stress exposures. Dr Kerry Ressler discussed a body of work exploring the modulation and extinction of fear memories in rodents and humans, especially focusing on the role of key neurotransmitter systems including excitatory amino acids and brain-derived neurotrophic factor. Dr Israel Liberzon presented recent results on human decision-making processes in response to exogenous glucocorticoid hormone administration. Overall, these discussions are casting a wider framework on the cognitive/affective processes that are distinctly regulated by the experience of stress and some of the brain regions and neurotransmitter systems associated with these effects.     

Gender differences in the negative affective priming of aggressive behavior

The negative affective priming of aggression was examined across different aversive contexts (general stress exposure and frustration) with a laboratory aggression paradigm that measured the intensity of shocks participants delivered to a putative employee. Participants' emotional responses were gauged via startle eyeblink reactions and self-report mood ratings. Aside from gender differences in overall aggression, men but not women exposed to general stress showed significant increases in aggression across blocks. However, frustration produced increases in aggression in both genders. Although both genders showed robust startle increases during stress, startle activation was related to increases in aggression in men and decreases in aggression in women. These findings suggest that general stress and experiences of negative emotion trigger physical aggressive responses more strongly in men than in women.     

Violent video games and aggressive behavior in young women

The increasing availability of violent video games and their implication in recent school shootings has raised the volume of public debate on the effects of such games on aggressive behavior and related variables. This article reports an experiment designed to test key hypotheses concerning the short term impact of exposure to violent video games on young women, a population that has received relatively little attention in this research literature. Results were that brief exposure to a violent video game increased aggressive behavior. Mediational analyses suggested that the violent video game effect on aggression was not mediated by instrumental aggressive motivation, but was partially mediated by revenge motivation. Other results suggested that the violent video game effect on aggression might be greater when the game player controls a same‐sex violent game character. Aggr. Behav. 29:423–429, 2003. © 2003 Wiley‐Liss, Inc.     

Red and romantic behavior in men viewing women

In many non‐human primate species, a display of red by a female increases attraction behavior in male conspecifics. In two experiments, we investigate an analogous effect in humans, specifically, whether red on a woman's shirt increases attraction behavior in men. In Experiment 1, men who viewed an ostensible conversation partner in a red versus a green shirt chose to ask her more intimate questions. In Experiment 2, men who viewed an ostensible interaction partner in a red versus a blue shirt chose to sit closer to her. These effects were observed across participants' perceptions of their own attractiveness (Experiment 1) and general activation and mood (Experiment 2). Our findings suggest that red acts as a basic, non‐lexical prime, influencing reproduction‐relevant behavior in like manner across species. Copyright © 2010 John Wiley & Sons, Ltd.     

Neurochemical mechanisms underlying amygdaloid modulation of aggressive behavior in the cat

Studies designed to determine the respective roles of substance P, excitatory amino acids, and enkephalins in amygdaloid modulation of defensive rage behavior in the cat are presented. The basic design of these studies involved three stages. In stage I, cannula electrodes for stimulation and drug infusion were implanted into medial hypothalamic or midbrain periaqueductal gray (PAG) sites from which defensive rage behavior could be elicited. Then, a stimulating electrode was implanted into a site within the medial, basal, or central nuclear complex from which modulation of the defensive rage response could be obtained. Amygdaloid modulation of defensive rage was determined in the following manner: it employed the paradigm of dual stimulation in which comparisons were made of response latencies between alternate trials of dual (i. e., amygdala = medial hypothalamus [or PAG]) and single stimulation of the hypothalamus or PAG alone. Thus, stage I established the baseline level ofmodulation (i. e., facilitation or suppression of defensive rage) in the predrug stimulation period. In stage II, a selective or nonselective receptor antagonist for a given transmitter system was administered either peripherally or intracerebrally at the defensive rage site, after which time the same dual stimulation paradigm was then repeated over the ensuing 180 min postinjection period in order to determine the effects of drug delivery upon amygdaloid modulation of defensive rage. Stage III of the study took place at the completion of the pharmacological testing phase. The retrograde axonal tracer, Fluoro-Gold, was microinjected into the defensive rage site within the medial hypothalamus or PAG, and following a 6-14 day survival period, animals were sacrificed and brains were processed for histological and immunocytochemical analyses for the neurotransmitters noted above. This procedure thus permitted identification of cells within the amygdala which were labeled retrogradely and which were also immunostained positively for substance P, excitatory amino acids, or enkephalin. For studies involving substance P, defensive rage was elicited from the medial hypothalamus and for studies examining the roles of excitatory amino acids and enkephalin, defensive rage was elicited from the PAG. In the first study, facilitation of hypothalamically elicited defensive rage was obtained with dual stimulation of the medial nucleus of the amygdala. In separate experiments, the selective NK₁ non-peptide antagonist, CP 96,345, was administered both peripherally as well as intracerebrally into the hypothalamic defensive rage sites in doses of 0.5-4.0 mg/kg (i. p.) and 0.5-2.5 nmol (i. c.). Following drug delivery, the facilitatory effects of medial amygdaloid stimulation were blocked in a dose- and time-dependent manner in which the effects were noted as early as 5 min postinjection. The maximum drug dose (4.0 mg/kg) employed for peripheral administration resulted in a 42% reduction in the facilitatory effects of the medical amygdala (P < 0.002). This drug, when microinjected directly into medial hypothalamic defensive rage sites at the maximum dose level of 2.5 nmol, resulted in an 84% reduction of the suppressive effects of amygdaloid stimulation (P < 0.5) at 5 min postinjection. In the next study, an N-methyl-D-aspartate (NMDA) antagonist, DL-α-amino-7-phosphonoheptanoic acid (AP-7), was administered either peripherally (0.1-1.0 mg/kg) or intracerebrally (0.2 and 2.0 nmol) into PAG defensive rage sites. Facilitation of defensive rage behavior, which was observed following dual stimulation of the basal amygdala and PAG, was significantly reduced by either route of drug administration in a dose- and time-dependent manner. At the maximum dose level of peripheral administration, AP-7 reduced amygdaloid facilitation of defensive rage by 63% (P < 0.001) for 60 min, postinjection. A smaller (i. e., 19%) but still significant (P < 0.05) reduction in facilitation was obtained following intracerebral administration of the drug. In a third study, the non-selective opioid receptor antagonist, naloxone (27.5 nmol), infused directly into PAG defensive rage sites, totally blocked the suppressive effects of central amygdaloid stimulation for a period of 30 min (P < 0.05) in a dose- and time-dependent manner. The anatomical phase of this study revealed the following relationships: 1) that large numbers of neurons projecting to the medial hypothalamus from the medial amygdala immunoreact positively for substance P; 2) that neurons projecting to the PAG from the basal complex of amygdala immunoreact positively for glutamate and aspartate; and 3) that neurons located within the central nucleus of the amygdala which project to the PAG immunoreact positively for met-enkephalin. Collectively, these observations provide new evidence which characterizes the likely neurotransmitters linked with specific amygdaloid pathways subserving the modulation of defensive rage behavior in the cat.     

Startle modulation in non-incarcerated men and women with psychopathic traits

Past research has demonstrated that individuals with psychopathic characteristics are under-responsive to aversive stimuli, however, much of this work has failed to include non-incarcerated samples, or to examine gender differences in this relationship. Additionally, few studies have examined the role of specific personality characteristics, as they relate to both psychopathic behavior and emotional responsiveness. The current study assessed emotional modulation of the startle response in a community sample of 108 men and women (99 with usable startle data) during perception of emotion-laden photographs. Consistent with previous work, men reporting high levels of psychopathy failed to show the typical increase in the startle response when exposed to aversive photographs, but only when responses were elicited relatively early in picture viewing (i.e., 2.0 s as compared to 4.5 s post-photograph onset). Additionally, both genders showed a significant effect of harm avoidance and anxiety on modulation of the startle response, such that individuals reporting low levels of each trait failed to show significant responses to aversive photographs. These results suggest that while deficits in emotional processing extend to non-incarcerated samples, the relationship may be influenced by additional factors including gender, personality, and attributes related to incarceration.     

Startle modulation in non-incarcerated men and women with psychopathic traits

Past research has demonstrated that individuals with psychopathic characteristics are under-responsive to aversive stimuli, however, much of this work has failed to include non-incarcerated samples, or to examine gender differences in this relationship. Additionally, few studies have examined the role of specific personality characteristics, as they relate to both psychopathic behavior and emotional responsiveness. The current study assessed emotional modulation of the startle response in a community sample of 108 men and women (99 with usable startle data) during perception of emotion-laden photographs. Consistent with previous work, men reporting high levels of psychopathy failed to show the typical increase in the startle response when exposed to aversive photographs, but only when responses were elicited relatively early in picture viewing (i.e., 2.0 s as compared to 4.5 s post-photograph onset). Additionally, both genders showed a significant effect of harm avoidance and anxiety on modulation of the startle response, such that individuals reporting low levels of each trait failed to show significant responses to aversive photographs. These results suggest that while deficits in emotional processing extend to non-incarcerated samples, the relationship may be influenced by additional factors including gender, personality, and attributes related to incarceration.     

Perceptions of job characteristics and affective work outcomes for women and men

One hundred twenty-three men and women participated in a study designed to assess their attitudes about job dimensions and affective work outcomes. This study found that very few differences existed between women's and men's perceptions of job dimensions and work outcomes. It was also shown that little difference existed between men's and women's perceptions of positive relationships between job dimension and affected work outcomes. The authors concluded that differences that exist in work attitudes are artifacts of hierarchical position and sex-role stereotyping and will disappear when women are allowed to move into jobs that are characterized by the presence of high levels of intrinsic job dimensions.     

Physiological arousal,exposure to a relatively lengthy aggressive film,and aggressive behavior

Male college students viewed either a 15-minute aggressive television program excerpt or a neutral one. Half of the students in each group were then angered or treated in a neutral fashion by a confederate. Each subject was allowed to retaliate by delivering electric shocks to the confederate as an evaluation of a problem solution he supposedly had completed. Heart rate was measured (a) before exposure to the television program, (b) after exposure to the program, (c) immediately before delivering the shock, and (d) immediately after shock delivery. Angered men who had seen the aggressive film were most aggressive toward the confederate and exhibited the lowest average pulse rates both before and after shock delivery. The findings are discussed in terms of their implication for arousal vs disinhibition conceptualizations of aggressive behaviors following exposure to television violence.     

Salivary testosterone and self-report aggressive and pro-social personality characteristics in men and women

Measures of salivary testosterone and the personality dimensions of aggression and pro-social behavior were obtained in 306 (155 male and 151 female) university students. Each participant provided two samples of saliva and completed ten self-report personality scales from multiple inventories. A factor analysis of the personality scales produced two factors, an aggression factor and a pro-social behavior factor. Men averaged five times the amount of salivary testosterone as women (99 pg/ml vs. 18.5 pg/ml) and rated themselves as more aggressive and less nurturant. Within each sex, testosterone was positively correlated with aggression and negatively correlated with pro-social personality. Structural equation modelling analyses suggested that a direct effect model best described the relationship between salivary testosterone and the latent personality dimensions of aggression and pro-social behavior. © 1996 Wiley-Liss, Inc.     

Stress impairs acquisition of delay eyeblink conditioning in men and women

In rodents stress impairs delay as well as trace eyelid conditioning in females, but enhances it in males. The present study tested the effects of acute psychosocial stress exposure on classical delay eyeblink conditioning in healthy men and women. In a between subject design, participants were exposed to psychosocial stress using the Trier Social Stress Test (TSST) or a control condition which was followed by a delay eyeblink classical conditioning procedure. Stress exposure led to a significant increase in salivary cortisol and impaired acquisition of conditioned eyeblink responses (CRs). This was evident by a later first CR and an overall lower CR rate of the stress group. The stress-induced acquisition impairment was observed in both women and men. Subjects failing to show a stress-induced cortisol increase (cortisol non-responder) were not impaired in acquisition. Our findings indicate that acute stress, possibly via activation of the hypothalamus–pituitary–adrenal (HPA) axis, reduces the ability to acquire a simple conditioned motor response in humans.     

Coronary-prone behavior may be declining in Danish men and women

Four hundred males and four hundred females were randomly selected from the Danish population and received the Jenkins Activity Survey (JAS) on two occasions, once in 1988 and again in 1992. The JAS was rated by the standard procedure, providing a measure of the degree of time urgency and ambitiousness (Factor A), speed and impatience (Factor S), hard-driving and competitiveness (Factor H) and job involvement (Factor J) shown by the subjects. The scores obtained for all four factors tended to be lower in 1992 than in 1988, and the differences were significant for Factor H. In addition, gender differences were observed for Factors A, S and J, with higher scores being obtained by males than by females. Age-related differences were observed for Factors A and J. The findings indicate that Type A behaviors have declined during the past four years in the Danish adult population and that different strategies may be required for encouraging health behaviors in men and women.     

Stress and health among women and men in a Swedish telecom company

The aim of the study was to investigate gender differences at managerial and nonmanagerial level in perceived stress and control and the relationship to health problems. Questionnaires were collected from 281 women and men at both managerial and nonmanagerial level in a sales department in a large Swedish telecom company. Items describing sources of stress were selected from Dallner, Gamberale, Olsson, and Örelius (1999) and developed through a group interview. The results showed only minor differences in perceived stress and no differences in perceived control when comparing men and women working at the same level in the organization. Instead the differences in perceived stress and control were found between managers and nonmanagers. In addition, the study showed both differences and similarities in explaining health symptoms for women and men at the same organizational level. Similarities were found at a nonmanagerial level but at a managerial level health problems were not predicted by the same factors for women and men. The need to consider organizational level in future studies about stress and gender is addressed.     

Phasic affective modulation of creativity

Thus far, it has been shown that positive compared to negative mood increases creativity, for instance, as measured by performance in the remote associate task, where participants are asked to find the common remote associate for three clue words (e.g., RABBIT CLOUD MILK solution word WHITE). The present experiments show that very brief variations in affect, lasting for only a few seconds and changing from trial to trial within participants, are sufficient to modulate creativity in that task, presumably by modulating the breadth of semantic spread. Using word valence of remote associates themselves (Experiment 1), and consonant and dissonant chords (Experiment 2) as affect inductions, it was observed that brief positive compared to negative affect increased creative performance. This evidence extends the affect-modulation hypothesis to a temporal micro-level.     

Desensitization to media violence: links with habitual media violence exposure, aggressive cognitions, and aggressive behavior

This study examined the links between desensitization to violent media stimuli and habitual media violence exposure as a predictor and aggressive cognitions and behavior as outcome variables. Two weeks after completing measures of habitual media violence exposure, trait aggression, trait arousability, and normative beliefs about aggression, undergraduates (N = 303) saw a violent film clip and a sad or a funny comparison clip. Skin conductance level (SCL) was measured continuously, and ratings of anxious and pleasant arousal were obtained after each clip. Following the clips, participants completed a lexical decision task to measure accessibility of aggressive cognitions and a competitive reaction time task to measure aggressive behavior. Habitual media violence exposure correlated negatively with SCL during violent clips and positively with pleasant arousal, response times for aggressive words, and trait aggression, but it was unrelated to anxious arousal and aggressive responding during the reaction time task. In path analyses controlling for trait aggression, normative beliefs, and trait arousability, habitual media violence exposure predicted faster accessibility of aggressive cognitions, partly mediated by higher pleasant arousal. Unprovoked aggression during the reaction time task was predicted by lower anxious arousal. Neither habitual media violence usage nor anxious or pleasant arousal predicted provoked aggression during the laboratory task, and SCL was unrelated to aggressive cognitions and behavior. No relations were found between habitual media violence viewing and arousal in response to the sad and funny film clips, and arousal in response to the sad and funny clips did not predict aggressive cognitions or aggressive behavior on the laboratory task. This suggests that the observed desensitization effects are specific to violent content.     

Justification of violence as a mediator between exposure to violence and aggressive behavior in children

The aim of this study was to evaluate the mediating role of the justification of violence schema in the relationship between exposure to violence and reactive and proactive aggressive behavior. We differentiated between direct and indirect exposure in four contexts: home, neighborhood, school and TV. A total of 675 children, aged between 8 and 12 years, participated in the study. They answered questionnaires about exposure to violence, justification of violence, and proactive and reactive aggressive behavior in two waves six months apart. The results showed that witnessing violence at home and on TV predicted aggressive behavior, and this relationship was mediated by the justification of violence. Victimization in all contexts predicted aggressive behavior and this relationship was generally mediated by the justification of violence.     

Load-dependent modulation of affective picture processing

Because of the biological significance of emotional stimuli, their processing is considered largely automatic. In the study reported herein, we tested the alternative hypothesis—namely, that the processing of emotional stimuli requires some level of attention. Our experiments utilized highly negative and arousing visual stimuli comprising mutilated bodies. All experiments employed a single task, which consisted of determining whether two peripheral bars were like oriented or not, thereby eliminating potential task-difference confounds that may have contaminated prior studies. Our results revealed that task-irrelevant unpleasant images slowed reaction time during the performance of the main task. Such interference was modulated by task difficulty as well as by alcohol consumption, showing that the processing of emotional visual stimuli is not immune to attentional manipulations. These results suggest that it is essential to utilize attentional manipulations that more fully consume attentional resources in order to demonstrate that the processing of emotional stimuli is resource limited.