Immediate and enduring effects of corticosterone administration during adolescence and adulthood on anxiety and depressive behavior in male rats

Previous research has shown that the stress hormone corticosterone can increase depressive and anxiety-like behavior in rats as well as dampen the HPA response to a novel stressor (Kalynchuk et aI., 2004; Johnson et aI., 2006). Several studies have also shown that adolescence is a period of increased sensitivity to the negative effects of stressors (reviewed in McCormick et aI., 2010), which are often the result of exposure to corticosterone, and yet there is no research to date examining the effects of corticosterone administration during adolescence. The purpose of these experiments is to determine both the immediate and enduring effects of prolonged exposure to corticosterone in adolescence and adulthood on anxiety-like behavior, depressive behavior, and the HPA response. In Experiment 1 adolescent and adult rats were administered an injection of 40 mg/kg of corticosterone or vehicle daily for 16 days. Ha l f of the rats were then tested on the elevated plus maze (EPM) one day after their last injection, and the following day were tested on the forced swim test (FST). After the FST, which is a stressor, blood samples were collected at three time points, and the plasma concentrations of corticosterone were determined using a radioimmunoassay. The remaining rats were left undisturbed for three weeks, and then underwent the same testing as the first group. Corticosterone treatment had little effect on anxiety-like and depressive behavior, but it did alter the HPA response to the FST. In those rats tested soon after the period of injections, corticosterone dampened the HPA response as compared to vehicle treated rats in both adolescent and adult treated rats. For the adolescent treated rats that were tested several weeks later, corticosterone treatment increased HPA response as compared to the vehicle treated rats, but the same was not true for the adult treated rats. I t was hypothesized that the lack of behavioral effects of the corticosterone treatment may be the result of the vehicle injections inducing a stress response and thereby both groups would have similarly altered behavior. In Experiment 2 rats were administered corticosterone dissolved in their drinking water with 2.5% ethanol, or jus t the 2.5% ethanol or plain water, to determine the effects of corticosterone treatment without a stressor present. The regular drinking water was replaced with treated water for 16 days either during adulthood or adolescence, and as before, rats were either tested in the FST one day after the water was removed or three weeks later. Again there was no effect of treatment on depressive behavior. Similar to what was observed in Experiment 1, corticosterone treatment dampened the HPA response to a stressor for the rats tested soon after the treatment period. However, in Experiment 2 there was no effect of treatment on HPA response in those rats tested several weeks after they were treated. These results indicate that corticosterone can have a lasting effect on the HPA when administered in adolescence by injections but not in drinking water, which is likely because of the different schedules of exposure and rates of absorption between the two administration methods.

Personality traits and personal values : an investigation into the importance of each in the prediction of behaviour /

Personality traits and personal values are two important domains of individual differences. Traits are enduring and distinguishable patterns of behaviour whereas values are societally taught, stable, individual preferences that guide behaviour in order to reach a specific end state. The purpose of the present study was to investigate the relations between self and peer report within the domains of personality traits and values, to examine the correlations between values and traits, and to explore the amount of incremental validity of traits and values in predicting behaviour. Two hundred and fiftytwo men and women from a university setting completed self and peer reports on three questionnaires. In order to assess personality traits, the HEXACO-PI (Lee & Ashton, 2004) was used to identify levels of 6 major dimensions of personality in participants. To assess values, the Schwartz Value Survey (Schwartz, 1992) was used to identify the importance each participant placed on each of Schwartz's 10 value types. To measure behaviour, a Behavior Scale, created by Bardi and Schwartz (2003), consisting of items designed to measure the frequency of value-expressive behaviour was used. As expected, correlations between self and peer reports for the personality scales were high indicating that personality traits are easily observable to other people. Correlations between self and peer reports for the values and behaviour scales were only moderate, suggesting that some goals, and behaviours expressive of those goals, may not always be observable to others. Consistent with previous research, there were many strong correlations between traits and values. In addition to the similarities with past research, the present study found that the personality factor Honesty-Humility was correlated strongly with values scales (with five correlations exceeding .25). In the prediction of behaviour, it was found that both personahty and values were able to account for significant and similar amounts of variance. Personality outpredicted values for some behaviours, but the opposite was true of other behaviours. Each domain provided incremental validity beyond the other domain. The impUcations for these findings, along with limitations, and possibilities for future research are also discussed.

Exploring the experience of the pioneers of change

The world of work with Western society appears to be undergoing a major change. The literature has described this phenomenon as a change from an industrialbased economy to a knowledge-based economy. This change will represent a complete transformation of the world of work; some suggest that everything we have come to accept and know as normal will change. Our present society seems to be in a period of transition. It is a time with many challenges and problems, many of which cannot be solved with thinking patterns from an old industrial-based economy. A fundamental shift in thinking patterns consistent with a new emerging world of work must take place. This change in thinking represents a fundmental shift from traditional and linear ways of seeing the world (worldview), to more holistic ways of seeing the world. In this investigation the word paradigm was used to define how people see their world. A paradigm shift is defined as a change in how a person sees their world: a change from an old to new or different way of viewing the world. Those individuals who are the first to shift their paradigm are called paradigm pioneers. These individuals do not only shift their ways of seeing the world, but they also begin to act and behave in ways consistent with the new paradigm. Thus far the research literature has adequately described the concepts of paradigms and paradigm shifts. However, little is known regarding how people actually and eventually make a shift. As it will be important for each individual to make a personal paradigm shift, then it will be extremely valuable to learn more about the process itself. The purpose of this investigation was to explore these issues in more detail and specifically, describe the experience of paradigm shifts and explore the experience of paradigm pioneers. A qualitative research methodology involving in-depth interviews was used to investigate the experiences of four participants identified as paradigm pioneers. It is interesting to note that the participants in this study did not describe an allencompassing paradigm shift. In fact, each participant, defined a paradigm shift in several different ways. They did relate several examples of paradigm shifts. However, even among these examples, there was a high degree of variability. The findings of this investigation centered upon the participants' experience as pioneers. Each pioneer shared many of the same qualities, the first quality of which described how these pioneers dealt with change. I called this a change-sense quality. The pioneers viewed change in an open and positive manner, and were also aware of change taking place in their world. Finally, they displayed an understanding of change, and a bias to take positive action in the face it. The participants also shared an inner quality. The four pioneers demonstrated a personal purpose and vision, and were selfdirected individuals. They also had an innate curiosity which translated into a love of learning. They also displayed a quality where relationships with others were highly valued. Relationships were important to the pioneers because they played a support role to help them deal with the challenges of being a pioneer. Pioneers also valued relationships because, they relied on others to make change happen. The above mentioned qualities enabled pioneers to be effective in a changing world of work. The findings from this investigation have many implications for research and practice. First, the concept of paradigms and paradigm shifts must be further researched. A great deal more must be learned in order to better understand the kind of shift individuals must make to be effective in the new world of work. Second, the qualities displayed by pioneers are important for all members of the world of work to develop. The qualities shared by pioneers appeared to represent an enduring set of traits that can possibly help individuals deal more positively with uncertainty and rapid change taking place in today's North American world of work.

Ten years after : a qualitative study of students' experiences in a high school theatre company

This qualitative study explored 4 former students' perceptions of the learning associated with their involvement in a high school theatre program and the contextual factors they linked to their perceived development. The study involved 4 adult participants, 2 male and 2 female, who had participated extensively in a high school theatre company from 1996 to 2001 when they were students in a large Ontario school board. Data were collected from January to August, 2007, when the 4 former students took part in two in-depth, open-ended interviews. The focus of investigation was participant perspectives. Data analysis revealed that the 4 participants' involvement in high school theatre produced both wide-ranging and enduring developmental benefits across personal, social, and cognitive domains. Participants achieved these benefits through interactions among 3 related contexts: (a) rehearsal and performance practices, (b) the world of the play, and (c) characteristics of the high school theatre company.

Predictors of shy children's coping with a social conflict : mediators and moderators

Shy children are at risk for later maladjustment due to ineffective coping with social conflicts through reliance on avoidance, rather than approach-focused, coping. The purpose of the present study was to explore whether the relation between shyness and children's coping was mediated by attributions and moderated by personality selftheories and gender. Participants included a classroom-based sample of 175 children (93 boys), aged 9-13 years (M = 10.11 years, SD = 0.92). Children completed self-report measures assessing shyness, attributions, personality self-theories and coping strategies. Results showed that negative attribution biases partially mediated the negative relations between shyness and social support seeking, as well as problem-solving, and the positive association between shyness and externalizing. Moreover, self-theories moderated the relation between shyness and internalizing coping at the trend level, such that the positive relation was exacerbated among entity-oriented children to a greater degree than incrementally-oriented children. In terms of gender differences, shyness was related to lower use of social support and problem-solving among incrementally-oriented boys and entity-oriented girls. Thus, shy children's perceptions of social conflicts as the outcome of an enduring trait (e.g., social incompetence) may partially explain why they do not act assertively and aggress as a means of social coping. Furthermore, entity-oriented beliefs may exacerbate shy children's reliance on internalizing actions, such as crying. Although an incrementally-oriented stance may enhance shy girls' reliance on approach strategies, it does not appear to serve the same protective role for shy boys. Therefore, copingoriented interventions may need to focus on restructuring shy children's social cognitions and implementing gender-specific programming for their personality biases.