Sex differences in chronic stress effects on memory in rats

Recent studies in rodent models and in humans have shown that the status of both the gonadal and adrenal axes (hypothalamic-pituitary-gonadal, HPG and hypothalamic-pituitary-adrenal, HPA, respectively) can influence learning and memory function. In this article, the effects of activating the HPA axis (stress) on performance of memory tasks in rats are reviewed. More importantly, results are presented which show that chronic stress has a different impact on performance of these tasks depending upon the sex of the rat. These observations are novel and potentially important since few studies, animal or human, have utilized females as subjects in studies of the stress response. Sex differences in the effects of chronic stress on memory were investigated in rats using an object recognition task and two spatial memory tasks, radial arm maze and object location. Given the same chronic stress--21 days of restraint for 6 h each day--males were impaired in all of the memory tests while females showed enhanced performance of the spatial memory tasks and no changes in object recognition performance. Levels of neurotransmitters and metabolites were measured in brain areas important for cognition in the subjects in order to determine neural systems that may respond to stress and mediate the cognitive responses. These results show that responses of monoamine and amino acid containing neural systems may contribute to or underlie sex differences in stress effects on cognition. Stress decreased dopaminergic activity in the frontal cortex and amygdala of males but not females; whereas, in CA3 of the hippocampus, stress increased levels of 5-HT and norepinephrine in females, but not males, and increased GABA in males, but not females. Finally, a possible role for estradiol in mediating sexually differentiated responses to stress was examined. Behavioral and neurochemical evaluations in ovariectomized, stressed females, with or without estrogen replacement, suggest that sex differences in response to stress are influenced by both the organizing and activating effects of estradiol. A few, recent studies in humans, that show sexually dimorphic relationships between chronic stress and cognition, are also highlighted. These results in humans are consistent with the pattern of results in rats. Clearly, further studies are necessary to substantiate sex differences in stress effects on memory function in humans and to understand mechanisms whereby estrogen may influence the stress response in rats. Nonetheless, recent studies show sexually differentiated cognitive responses to chronic stress and underline the importance of considering the sex/gender of subjects when studying the stress response.     

Left-side infant holding: a test of the hemispheric arousal-attentional hypothesis

When asked to hold a young infant in their arms, most adults hold on the left side (Harris, 1997). In a prior study, we found the same bias when we asked adults merely to imagine holding an infant in their arms (Harris, Almerigi, & Kirsch, 1999). It has been hypothesized that the left-side bias is the product of right-hemisphere arousal accompanying certain aspects of the act, causing attention to be driven to the contralateral, or left, side of personal space. Left-side holding, whether actual or imagined, thus would be consistent with the direction to which the holder's attention has been endogenously directed. We tested this hypothesis by giving 250 college students the "imagine-holding" task and then, as an independent measure of lateralized hemispheric arousal, a 34-item Chimeric Faces Test (CFT). On the "imagine" test, a significant majority reported a left-side hold, and, on the CFT, left-side holders had a significantly stronger left-hemispace bias than right-side holders, although both left- and right side holders had left-hemispace CFT biases. The results thus support the attentional-arousal hypothesis but indicate that other factors are contributing as well.     

Alive communication

The purpose of this paper is to propose a theoretical model, based on a dynamic systems perspective and the metaphor of aliveness in communication. Traditional concepts and methods for the study of communication are relatively static and based on the metaphor of signal and response. These traditional methods lend themselves to relatively simplified measures of frequencies and durations, sequences and co-occurrences: a model of objectified communication. The concept of alive communication focuses on the dynamically changing aspects of communication using three related components: coregulation, ordinary variability, and innovation. Like living organisms, alive communication develops over time as it forms dynamically stable patterns. Aliveness can be applied to communication at any age, in any species, between species, in any form including time-delayed practices using written symbols, and with non-living objects. The model provides a tool for evaluating the "life-likeness" of communication with animate and inanimate objects and robotic devices, and for assessing and treating communicative difficulties--in which aliveness is missing--within and between dyads/families.     

Why do Managers Engage in Trustworthy Behavior? A Multilevel Cross‐Cultural Study in 18 Countries

Drawing on theories of generalized exchange and the norm of indirect reciprocity, we conceptualize subordinates’ organizational citizenship behavior directed toward the organization (OCBO) and directed toward peers (OCBI) as antecedents of managerial trustworthy behavior and examine how managers’ affective trust in subordinates mediates this relationship. We also investigate the extent to which this mediation is moderated by the level of collectivism in a society. Data were collected from 741 managers and 2,111 subordinates in 18 countries representing all major cultural regions of the world. We find support for our hypothesized moderated mediation in that managers’ affective trust in subordinates mediates the relationships between both subordinates’ OCBO and managerial trustworthy behavior, and subordinates’ OCBI and managerial trustworthy behavior across the different countries studied. Further, managers’ affective trust in subordinates only mediates the relationships between both types of citizenship behavior and managerial trustworthy behavior when collectivism is low to medium but not when it is high. Implications for research on cross‐cultural psychology, trust, and organizational citizenship behavior are discussed.     

Counseling Outcomes for Youth With Oppositional Behavior: A Meta‐Analysis

This meta‐analysis of clinical trials explored the effectiveness of treatments targeted at changing oppositional behavior. The meta‐analysis included 31 peer‐reviewed treatment studies with school‐age youth ages 6–17 years identified as having oppositional defiant disorder. Results were synthesized using a random effects model for mean difference and mean gain effect size estimates. Findings suggest that counseling/psychotherapy is effective in treating oppositional behavior in school‐age youth at termination, but the long‐term efficacy of such treatment is less stable.