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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.  相似文献   
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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.  相似文献   
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Background Recent interest in the teaching of thinking skills within education has led to an increase in thinking skills packages available to schools. However many of these are not based on scientific evaluation ( DfEE, 1999 ). This paper endeavours to examine the effectiveness of one approach, that of infusion, to teaching thinking. Aims To investigate the impact of an infusion methodology, activating children's thinking skills (ACTS), on the cognitive, social, and emotional development of children in Year 4–6 in primary schools. This is a sister project to research being conducted in Northern Ireland ( McGuinness, 2006 ). Sample The study involved 404 children from 8 primary schools in one local authority. These were divided into 160 in the experimental group and 244 in the waiting list control group. Methods A quasi‐experimental design was used with pre‐, post‐, and delayed post‐tests to ascertain changes in children's cognitive abilities, self‐perceptions, and social/behavioural skills using quantitative measures. In addition qualitative techniques were used with pupils and teachers to evaluate effectiveness. Results The experimental group made significantly greater gains in cognitive ability skills over a 2 year period compared to the waiting list control. Qualitative data demonstrated a positive impact on children's social and emotional development. In addition teacher professional development was reported to be enhanced. Conclusions This research indicated that children's cognitive abilities can be developed following a 2 year period of the ACTS infusion intervention. While some positive effects were evidenced on the social and emotional development of children, further study will be necessary to examine these in more detail.  相似文献   
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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.  相似文献   
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Self-multiplicity is a widely recognized phenomenon within psychology. The study of how self-continuity emerges amidst self-multiplicity remains a crucial issue, however. Dialogical approaches are widely viewed as suitable for developing this field of study but they demand coherent methods compatible with their theoretical bases. After reviewing the available methods for the study of the dialogical self, as well as other dialogical methods for the study of psychotherapy, we conclude that we still lack a method which can be used by external observers and is devoted to the systematic tracing of the dialogical dynamics of self-positions as they unfold over time. A new method, positioning microanalysis, is described in detail as a possible way to overcome current limitations in methods focused on the dialogicality inherent in selfhood processes. Positioning microanalysis takes a genetic-developmental perspective on dialogical processes in the self and allows for the depiction of microgenetic movements of self-positions over time and the establishment of more or less stable sequences or patterns of positions. This is illustrated by its application to an emotion-focused therapy session.  相似文献   
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