McEwen-Induced Modulation of Endocrine History: A Partial Review

In endless facets of physiology, there are points of homeostatic balance, such that too much or too litttle of something can both be deleterious (i.e., an "inverse U" pattern). This is particularly true when considering glucocorticoids (GCs), the adrenals steroid secreted during stress. In the first part of this paper, I review a number of realms in which a paucity and an excess of GCs are both damaging. Some findings are classical (for example, concerning GC effects upon body weight), while some are quite recent and have considerable implications for both physiology and pathophysiology (for example, inverse U's of GC actions in the realm of immunity and neuronal survival). The second part of the review considers the far thornier issue of how such inverse U's of GC actions are generated on a cellular and molecular level. One solution that has evolved, primarily in the hippocampus within the nervous system, involves the presence of two different types of receptors for GCs within the same cells; so long as the two receptors have very different affinities and mediate opposing effects on some cellular endpoint, an inverse U will emerge. The second solution, found in a number of peripheral tissues, involves GCs having opposing effects on the amount of some signal being generated (e.g., an immune cytokine) and the sensitivity of target tissues to that signal; under conditions that appear to be physiologically relevant, inverse U's emerge from this pattern as well. The final section of this review considers the enormous role played by Bruce McEwen in the emergence of this literature. I suggest that while much of this obviously has to do with the facts that have come from his group, another substantial contribution is from his steadying and supportive personality, the veritable embodiment of homeostatic balance.     

Attention for emotional facial expressions in dysphoria: an eye-movement registration study

Former research demonstrated that depression is associated with dysfunctional attentional processing of emotional information. Most studies examined this bias by registration of response latencies. The present study employed an ecologically valid measurement of attentive processing, using eye-movement registration. Dysphoric and non-dysphoric participants viewed slides presenting sad, angry, happy and neutral facial expressions. For each type of expression, three components of visual attention were analysed: the relative fixation frequency, fixation time and glance duration. Attentional biases were also investigated for inverted facial expressions to ensure that they were not related to eye-catching facial features. Results indicated that non-dysphoric individuals were characterised by longer fixating and dwelling on happy faces. Dysphoric individuals demonstrated a longer dwelling on sad and neutral faces. These results were not found for inverted facial expressions. The present findings are in line with the assumption that depression is associated with a prolonged attentional elaboration on negative information.     

Developmental and sex-related differences in preschoolers' affective decision making

This study investigated developmental and sex-related differences in affective decision making, using a two-deck version of Children's Gambling Task administered to 3- and 4-year-old children. The main findings were that 4-year-old children displayed better decision-making performance than 3-year-olds. This effect was independent of developmental changes in inductive reasoning, language, and working memory. There were also sex differences in decision-making performance, which were apparent only in 3-year-old children and favored girls. Moreover, age predicted awareness of task and the correlation between the latter and decision-making performance was significant, but only in 4-year-old children. This study thus indicates that there is a remarkable developmental leap in affective decision making, whose effects are apparent around the age of 4, which according to our results, also marks the age when the correlation of declarative knowledge and decision-making performance becomes significant.     

Sport participation and stress among women and men

ObjectivesIn-depth analysis of the relationship between sports participation and stress among adult women and men.Design644 women and 783 men, 20–65 years, from the SPAH Flemish-Policy-Research-Centre, reported data on participation in favourite sports and mental health.MethodGender-specific multiple MANOVAs with stress appraisal and the stress response of emotional distress as dependent variables, and participation in 15 different types of sports as independent variables, including effect sizes (Cohen’s d) per sport-type.ResultsVery little difference in perceived-stress and emotional-distress existed in women and men who participated in different sport-types, suggesting that “one-activity-fits-all recommendations” are likely inappropriate. Different sports are suitable for different individuals, and it is important that one finds the sport that suits one best. Conversely, significant associations between participation in walking and in meditation sports manifested with both stress appraisal and emotional distress among women, and significant associations between participation in ball games and in water sports manifested with emotional distress among men.ConclusionsThe paper gathered substantial comprehensive insight and connected its quantitative data to existing qualitative data, presenting stimulating theoretical arguments. Sport-type related variations in the physical activity – mental health relationship were analyzed, based on the theory of mindful movement and the complexity paradigm identifying 3 coordinates on which the physical activity – mental health complexity unravels, based on: activity domains, mental health dimensions, and individual characteristics. The mindful movement theory proposes an underlying mechanism that could explain the positive physical activity – mental health relationship, and the complexity paradigm provides basis for creating a workable definition for ther concept of mindful physical activity.     

Mechanisms underpinning successful decision making in skilled youth soccer players: an analysis of visual search behaviors

The authors examined the complex interactions between perception, cognition, and expertise by using a film-based decision-making test. They stratified 40 youth soccer players (aged 13.0-15.8 years) into groups by using a within-task criterion. They assigned the players to successful or less successful groups on the basis of their performance on a laboratory-based test of tactical skill. Using soccer-specific film simulations, movement-based response measures, and eye movement registration techniques, the authors determined the players' decision-making processes and skill level. The results showed that investigators can use film-based tests to discriminate soccer players of comparable experience and playing level on the basis of their decision-making skills. When compared with their less successful counterparts, successful decision-makers used more goal-oriented search strategies, which resulted in superior performance, as characterized by faster decision times and greater response accuracy. Successful decision-makers (a) spent more time fixating the player in possession of the ball and (b) alternated gaze more frequently between that player and other areas of the display. An earlier study in which researchers (R. Vaeyens, M. Lenoir, A. M. Williams, L. Mazyn, & R. M. Philippaerts, 2007) stratified participants into groups on the basis of playing level had not revealed those differences. The implication of the present findings is that a within-task criterion provides investigators with a more sensitive approach when they try to identify the mechanisms underlying decision-making skill. Implications for research and practice are discussed.     

Stress, Glucocorticoids, and Damage to the Nervous System: The Current State of Confusion

An extensive literature demonstrates that glucocorticoids (GCs), the adrenal steroids secreted during stress, can have a broad range of deleterious effects in the brain. The actions occur predominately, but not exclusively, in the hippocampus, a structure rich in corticosteroid receptors and particularly sensitive to GCs. The first half of this review considers three types of GC effects: a) GC-induced atrophy, in which a few weeks' exposure to high GC concentrations or to stress causes reversible atrophy of dendritic processes in the hippocampus; b) GC neurotoxicity where, over the course of months, GC exposure kills hippocampal neurons; c) GC neuroendangerment, in which elevated GC concentrations at the time of a neurological insult such as a stroke or seizure impairs the ability of neurons to survive the insult. The second half considers the rather confusing literature as to the possible mechanisms underlying these deleterious GC actions. Five broad themes are discerned: a) that GCs induce a metabolic vulnerability in neurons due to inhibition of glucose uptake; b) that GCs exacerbate various steps in a damaging cascade of glutamate excess, calcium mobilization and oxygen radical generation. In a review a number of years ago, I concluded that these two components accounted for the deleterious GC effects. Specifically, the energetic vulnerability induced by GCs left neurons metabolically compromised, and less able to carry out the costly task of containing glutamate, calcium and oxygen radicals. More recent work has shown this conclusion to be simplistic, and GC actions are shown to probably involve at least three additional components: c) that GCs impair a variety of neuronal defenses against neurologic insults; d) that GCs disrupt the mobilization of neurotrophins; e) that GCs have a variety of electrophysiological effects which can damage neurons. The relevance of each of those mechanisms to GC-induced atrophy, neurotoxicity and neuroendangerment is considered, as are the likely interactions among them.