The effect of stress on memory and the brain

描述（由申请人提供）：压力对心理健康有许多重要的影响。压力的增加通常会导致糖皮质激素的升高，这可能会对记忆和大脑产生影响。拟议的研究涉及两种类型的压力：营养（代谢）压力，通常由营养不足引起，以及社会心理压力，这可能由社会互动引起。本研究以山雀和灌丛鸦为研究对象，探讨应激激素如何介导营养和社会压力，以及应激激素对记忆和海马可塑性的影响。特异性目的1将通过皮质酮植入物在短期和长期基础上研究皮质酮是否直接参与介导鸟类海马的记忆表现和神经发生。具体目标2将调查社会优势互动是否会导致下属个体的压力增加，以及这种压力是否与压力激素水平的增加以及记忆和海马体的相应变化有关。具体目标3将验证发育过程中的营养压力导致应激激素水平升高、记忆性能下降和成年期海马形成变化的假设。首先，雏鸟在发育过程中接受限制饮食，在营养独立后，他们的记忆表现，皮质酮水平和神经发生率将与接受自由饮食的雏鸟进行比较。第二，所有的雏鸟在发育过程中都可以随意喂食，但是一半的雏鸟会吃含有皮质酮的食物，而另一半会吃含有安慰剂的食物。两组的记忆性能和神经发生率将在鸟类营养独立后进行比较。这项研究将为社会和营养压力如何影响皮质酮水平，以及这些变化如何介导成年动物的记忆和神经可塑性的改变提供重要的见解。这项研究将增加我们对压力对心理健康影响的认识，并将帮助我们理解压力反应的进化和适应意义。

DESCRIPTION (provided by applicant): Stress has many important implications for mental health. Increased stress usually results in elevation of glucocorticoid hormones, which, among many other effects, could have an impact on memory and the brain. The proposed research concerns two types of stress, nutritional (metabolic), which is usually caused by nutritional deficits, and psychosocial, which could be caused by social interactions. The main goal of the proposed study is to investigate how nutritional and social stress are mediated by stress hormones, and their effects on memory and hippocampal plasticity using mountain chickadees and scrub jays. Specific Aim 1 will examine whether corticosterone is directly involved in mediating memory performance and neurogenesis in the avian hippocampus on short- and long-term basis by using corticosterone implants. Specific aim 2 will investigate whether social dominance interactions result in increased stress in subordinate individuals and whether such stress is associated with increased levels of stress hormones and corresponding changes in memory and the hippocampus. Specific aim 3 will test the hypothesis that nutritional stress during development results in increased levels of stress hormones and in deteriorated memory performance and changes in the hippocampal formation during the adulthood. First, young birds will receive a restricted diet during their development and after becoming nutritionally independent their memory performance, levels of corticosterone and neurogenesis rates will be compared with those of young receiving ad libitum diet. Second, all young will be fed ad libitum during their development, but half of the birds will receive food containing corticosterone whereas the other half will receive food containing placebo. Memory performance and neurogenesis rates of both groups will be compared after birds become nutritionally independent. This study will provide important insights into how social and nutritional stress can affect levels of corticosterone, and how such changes mediate alterations in memory and neural plasticity in adult animals. This study will add to our knowledge of the effects of stress on mental health and will help us to understand the evolution and adaptive significance of stress responses.