STRESS, CORTISOL, AND COGNITIVE FUNCTION

该项目的具体目标是：(1)分离急性升高的皮质醇水平对认知功能的即时和延迟影响；(2)建立皮质醇分泌急性增加幅度与长期记忆变化之间的关系。皮质醇是肾上腺在面对生理或心理压力时释放的一种类固醇激素。许多研究报告了人类的认知变化与皮质醇的急性和慢性升高有关，包括注意力和言语记忆的缺陷。我们有理由认为，这些认知变化是皮质醇作用于神经组织的结果。我们知道皮质醇对神经组织的影响是复杂和非线性的，取决于数量和时间。我们还不了解的是皮质醇与神经组织的复杂相互作用是如何影响认知功能的。本实验验证了应激诱导的皮质醇增加将对认知产生不同影响的建议，这取决于两个相互作用的因素：(a)皮质醇分泌增加的持续时间，(b)皮质醇分泌增加的幅度。皮质醇升高的直接影响可能是增强即时和短期的认知过程（如注意力和记忆编码），而延迟影响可能是干扰长期过程（如记忆巩固和存储）。然而，与此同时，皮质醇的适度增加可能会促进长期过程，而相对较大的增加可能会产生有害影响。本实验旨在分离皮质醇对注意力和记忆影响的持续时间和程度。它测试了三个特定的假设：(a)当在实验室中诱导皮质醇急剧升高时，即时注意力过程和短期记忆将得到加强；(b)皮质醇的中度急性增加将与长期记忆增强有关；(c)皮质醇水平相对较高的急性升高与长期记忆障碍有关。这些假设将通过在一组人类参与者中诱导压力并测量(a)压力的自我报告、生理和皮质醇指标，以及(b)注意力和记忆任务的表现来测试。这些初步研究将为探索与慢性应激和皮质醇升高相关的慢性、海马介导的记忆障碍提供基础。

The specific aims of this project are to: (1) Dissociate immediate and delayed effects of acutely elevated cortisol levels on cognitive function; and (2) Establish the relationship between the magnitude of acute increases in cortisol secretion and changes in long-term memory. Cortisol is a steroid hormone released from the adrenal glands in response to physical or psychological stress. A number of studies have reported cognitive changes in humans associated with acute and chronic elevations in cortisol, including deficits in attention and verbal memory. It is reasonable to presume that these cognitive changes are the result of cortisol's actions on neural tissue. We know that cortisol's effects on neural tissue are complex and nonlinear, depending on amount and timing. What we do not yet understand is how cortisol's complex interactions with neural tissue affect cognitive function. This experiment tests the proposal that stress-induced increases in cortisol will have differing effects on cognition depending on two interacting factors: (a) the duration of increase in cortisol secretion, and (b) the magnitude of increase in cortisol secretion. The immediate effects of increased cortisol may be to enhance immediate and short-term cognitive processes, (e.g. attention and memory encoding), while the delayed effects may be to interfere with long-term processes (e.g. memory consolidation and storage). At the same time, however, moderate increases in cortisol may enhance long-term processes, while relatively large increases may have detrimental effects. This experiment is designed to dissociate the duration and magnitude effects of cortisol on attention and memory. It tests three specific hypotheses: (a) Immediate attentional processes and short-term memory will be enhanced when acute elevations in cortisol are induced in the laboratory; (b) Moderate acute increases in cortisol will be associated with long-term memory enhancements ; and (c) Relatively large acute elevations in cortisol will be associated with long-term memory impairments. The hypotheses will be tested by inducing stress in a group of human participants and measuring (a) self-report, physiological, and cortisol indicators of stress, and (b) performance on attention and memory tasks. These pilot studies will provide the foundation for exploring chronic, hippocampus-mediated memory disorders associated with chronic stress and elevated cortisol.