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，这在许多其他影响中，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），这通常是由营养不足引起的，和心理社会，这可能是由社会互动引起的。这项研究的主要目标是研究营养和社会压力是如何通过应激激素介导的，以及它们对山雀和灌丛鸦的记忆和海马可塑性的影响。具体目标1将研究皮质酮是否直接参与介导的记忆性能和神经发生在鸟类海马体中的短期和长期的基础上，通过使用皮质酮植入物。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将检验以下假设：发育过程中的营养应激导致应激激素水平升高，记忆力下降，成年期海马结构发生变化。首先，幼鸟在发育过程中将接受限制性饮食，在营养独立后，将其记忆表现、皮质酮水平和神经发生率与接受随意饮食的幼鸟进行比较。第二，所有幼鸟在发育过程中都可以随意进食，但一半的鸟将接受含有皮质酮的食物，而另一半将接受含有安慰剂的食物。两组的记忆表现和神经发生率将在鸟类变得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，并将帮助我们了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.