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，可能会对记忆力和大脑产生影响。这项拟议的研究涉及两种类型的压力，一种是通常由营养不足引起的营养(代谢)压力，另一种是可能由社会互动引起的心理压力。这项拟议的研究的主要目标是研究营养和社会压力是如何由应激激素调节的，以及它们对山雀和灌木鸟记忆和海马可塑性的影响。具体目标1将通过使用皮质酮植入物来检验皮质酮是否在短期和长期的基础上直接参与调节鸟类海马区的记忆表现和神经发生。具体目标2将调查社交优势互动是否会导致下属个体压力增加，以及这种压力是否与压力荷尔蒙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将测试这一假设，即发育期间的营养压力会导致应激激素水平上升，并导致记忆能力下降，以及成年后海马体结构的变化。首先，幼鸟在发育期间将接受有限的饮食，在获得营养独立后，它们的记忆表现、皮质酮水平和神经新生率将与接受自由饮食的幼鸟进行比较。其次，所有的幼鸟在发育过程中都将被随意喂养，但其中一半的鸟将获得含有皮质酮的食物，而另一半的鸟将获得含有安慰剂的食物。在鸟类获得营养独立后，将比较两组动物的记忆表现和神经形成率。这项研究将为社会和营养压力如何影响皮质酮水平，以及这种变化如何调节成年动物记忆和神经可塑性的变化提供重要的见解。这项研究将增加我们对压力对心理健康影响的了解，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.