Early-life stress affects extinction during critical periods of development: An analysis of the effects of maternal separation on extinction in adolescent rats

Adolescence is a period of heightened susceptibility to anxiety disorders, yet we have little experimental evidence on what factors may lead to psychopathology in adolescence. Preclinical models of extinction are commonly used to study the treatment of anxiety symptoms. Interestingly, recent research has shown that there are fundamental changes in the process of extinction across development, which may have implications for our understanding of psychopathology across the lifespan. Specifically, this research shows that the process of extinction parallels the nonlinear function of prefrontal cortex development, such that extinction behaviour is similar in juvenile and adult rats, but involves different processes in infancy and adolescence (periods of rapid growth and pruning, respectively). Our previous studies have shown that early-life stress accelerates the transition between infant and juvenile extinction systems. In the current series of experiments, we examined whether the same early-life stress, maternal separation (MS), would lead to an earlier transition between the juvenile and adolescent extinction systems, and between the adolescent and adult extinction systems. We show that MS adolescent rats exhibit more adult-like extinction behaviour, and that adolescent-like extinction emerges earlier in development (i.e. in pre-adolescent rats). These results may have important implications for the understanding and treatment of anxiety symptoms in adolescent populations.     

When the “Stakes” are Communicative

Stakeholders seek to have their “stakes” met by organizations. Organizations assess those requests and sometimes grant stakes to stakeholders. This study examines this critical function of organizations by investigating the stakeholder communication of 66 nonprofit organizations undergoing change. Implementers' self‐reports of frequency, timing, approaches, and topics of communication with 10 stakeholder groups were examined. Results indicate that implementers generally follow a quid pro quo “matching rule” wherein stakeholders' resource importance serves as the basis on which they are awarded communicative attention. However, observance of this rule was not predictive of implementers' assessments of successful change outcomes. Further, results also show that “internal” stakeholders receive the most and earliest communication, compared to stakeholders external to the organization or near the organization's boundary, and that “information dissemination” is the most prevalent communicative approach taken.     

The effect of feedback training on distance estimation in virtual environments

It is often noted that distances are significantly underestimated in computer‐simulated (virtual) environments. Two experiments examine observers' ability to use error corrective feedback to improve the accuracy of judgments of egocentric and exocentric distances. In Experiment 1, observers viewed objects in an immersive virtual environment and estimated their distance through a blindfolded walking task. Different groups received feedback on either egocentric, exocentric or none of these judgments. Receiving feedback improved observers' ability to estimate only those distances for which feedback was provided. These effects persisted for at least 1 week. In Experiment 2, observers estimated egocentric distance by means of both a direct and indirect walking task. Receiving feedback on the direct walking task predominantly improved direct estimates and not indirect estimates. These findings suggest that although feedback training offers a relatively straightforward and immediate way of overcoming problems of distance estimation, its effects are specific to both the type of judgment and the type of response. Copyright © 2005 John Wiley & Sons, Ltd.