Correlation between Changes in Stress-Induced Corticosterone Secretion and GR mRNA Levels

The current study was conducted to determine the potential relationship between stress-induced corticosterone secretion and corticosteroid receptor mRNA levels after 5 days of intermittent stress. In particular, we were interested in the rate at which animals terminate a stress response, and how this termination may be altered by repeated stress. Adult male Sprague-Dawley rats were subjected to either 5 days of restraint stress or 5 days of an unpredictable stress paradigm. Restraint-stress induced corticosterone secretion was measured on Days 1 and 5 in both groups, and animals were killed on Day 6. Glucocorticoid receptor (GR), and mineralocorticoid (MR) mRNA levels were determined using in-situ hybridization techniques. Five days of restraint stress caused an habituation of the plasma corticosterone response to stress measured 60 and 90 min post-stress initiation; this pattern of corticosterone secretion was not observed in the animals subjected to unpredictable stress. Five days of either stress paradigm did not alter MR mRNA levels measured within the hippocampus or GR mRNA levels within the hippocampus or the medial parvocellular division of the paraventricular nucleus of the hypothalamus (mpPVN). However, an individual's GR mRNA levels measured within the CA1/2 region of the hippocampus and the mpPVN were significantly correlated with the degree of habituation of the corticosterone response to stress measured on Day 5. This suggests that an increase in the rate of termination of the stress response and levels of GR within the hippocampus and mpPVN may be functionally related.     

Comparison of inhibition in two timed reaction tasks: the color and emotion Stroop tasks

The authors examined the cross-task consistency of the ability to inhibit the processing of irrelevant information. They compared interference scores on 2 widely used inhibition tasks and found that color word Stroop interference scores correlated with emotion word Stroop interference scores. An examination of physiological reactivity showed that, in general, the color Stroop was more arousing than was the emotion Stroop, most likely due to increased response conflict.     

Constructs of physical activity behaviour in children: The usefulness of Social Cognitive Theory

Objectives

The purpose of this study was to investigate the relationships among several Social Cognitive Theory (Bandura, 2004) constructs (e.g., self-efficacy) and children’s physical activity behaviours.

Design

Children from six elementary schools (N = 479) in grades 4th to 6th from five different school districts in the Southwestern USA participated in this study by completing a sociocognitive instrument as well as wearing a pedometer for five school days.

Methods

Previously validated scales were combined and administered to all children in order to examine the relationships among five constructs (self-efficacy, outcome expectations, social support, barriers, and goals) and physical activity participation was measured via pedometer. Data analyses included a two-step approach with confirmatory factor analysis followed by structural equation modelling.

Results

The confirmatory factor analyses indicated an adequate fit of the specified model. The structural model fit statistics also suggested that the data fit the specified model: χ² (8, N = 476) = 24.44, p = 0.00, χ²/df = 3.06, GFI = 0.98, AGFI = 0.96, CFI = 0.93, RMSEA = 0.07. The model explained 15% of the variance in social support, 11% of the variance in goals, 11% of the variance in barriers, 9% of the variance in outcome expectations, and 2% of the variance in physical activity. Self-efficacy was a strong predictor of total social support, total number of barriers, and outcome expectations.

Conclusions

This study supports the use of Social Cognitive Theory in understanding the constructs of physical activity behaviour in children, however, very little variance in behaviours was explained. There is a need to also investigate environmental influences on children’s decisions to be physically active.     

Why are you bringing up condoms now? The effect of message content on framing effects of condom use messages.

According to prospect theory (A. Tversky & D. Kahneman, 1981), messages advocating a low-risk (i.e., easy, low-cost) behavior are most effective if they stress the benefits of adherence (gain framed), whereas messages advocating a risky behavior are most effective if they stress the costs of nonadherence (loss framed). Although condom use is viewed as a low-risk behavior, it may entail risky interpersonal negotiations. Study 1 (N = 167) compared ratings of condom use messages advocating relational behaviors (e.g., discussing condoms) or health behaviors (e.g., carrying condoms). As predicted, loss-framed relational messages and gain-framed health messages received higher evaluations. Study 2 (N = 225) offers a replication and evidence of issue involvement and gender as moderators. Results are discussed with reference to the design of condom use messages.