Sleep Deprivation and Brain Function in Older Adults

描述(申请人提供)：急性完全睡眠剥夺(TSD)对大脑功能的影响还没有完全了解，特别是在大脑老化的背景下。TSD对年轻人的影响与正常衰老对大脑对认知挑战的反应之间有显著的相似之处。例如，在这两种情况下，神经成像研究都报告了相对于休息良好的年轻人来说，活动增加，一些人将这些变化解读为本质上的补偿。本研究将通过使用功能磁共振成像(FMRI)来测试大脑对TSD的代偿反应的限度，以研究健康的60岁以上的老年人和18-39岁的年轻人，在正常睡眠后和TSD后36小时。受试者将完成评估语言学习和算术工作记忆的认知任务。因此，这项研究将测试正常衰老是否会增强或抑制大脑对TSD的代偿反应，以及这种反应是否会因认知需求的不同而不同。据我们所知，虽然还没有研究使用功能神经成像来检查TSD对老年人的影响，但行为研究表明，老年人可能比年轻人更能适应TSD。这提出了一种耐人寻味的可能性，即老年人在TSD后表现出比休息良好的成年人更高的激活水平。此外，这项研究将测试这种在TSD后的激活增加，如果被发现，是否与TSD后的表现水平正相关。这将有助于解决TSD后大脑对认知任务反应的这些动态变化本质上是代偿的还是干扰正常的大脑功能。具体目标是：1)比较60岁以上成年人在正常睡眠后和36小时后TSD的大脑反应；2)确定TSD后大脑反应的变化是否与认知表现的变化有关；3)比较TSD对18-39岁的老年人和年轻人的神经认知影响。这项研究的总体目标是更好地理解和预测TSD的神经认知效应。此外，这项研究将提供关于大脑一般可塑性和补偿能力的有价值的信息，并可能为大脑老化的理论提供参考。

DESCRIPTION (provided by applicant): The effects of acute total sleep deprivation (TSD) on brain function are not fully understood, particularly in the context of brain aging. There are significant parallels between the effects of TSD in young adults and the effects of normal aging on cerebral responses to cognitive challenges. For example, in both cases, neuroimaging studies have reported increased activation relative to well-rested young adults and some have interpreted these changes as compensatory in nature. This study will test the limits of the cerebral compensatory response to TSD by using functional magnetic resonance imaging (FMRI) to study healthy older adults, 60+ years-old, and young adults, 18-39 years-old, after normal sleep and after 36 hours TSD. Subjects will perform cognitive tasks assessing verbal learning and arithmetic working memory. This study will thereby test whether normal aging potentiates or inhibits the brain's compensatory response to TSD and whether this response differs with different cognitive demands. While no studies, to our knowledge, have used functional neuroimaging to examine the effects of TSD in older adults, behavioral studies suggest that older adults may be more resilient to TSD than younger adults. This raises the intriguing possibility that older adults will show even greater levels of activation after TSD than well-rested adults. Furthermore, this study will test whether this increased activation following TSD, if found, is associated positively with performance levels following TSD. This will help address whether these dynamic changes in cerebral responses to cognitive tasks after TSD are compensatory in nature or interfere with normal brain function. Specific Aims are: 1) to compare the cerebral response of adults aged 60+ years after normal sleep and after 36 hours TSD; 2) to determine if changes in cerebral responses after TSD are associated with changes in cognitive performance; and 3) to compare the neurocognitive effects of TSD in older adults and younger adults, aged 18-39. The overall goal of this program of research is to better understand and predict the neurocognitive effects of TSD. Additionally, this study will provide valuable information about the general plasticity and compensatory capabilities of the brain and may inform theories of brain aging.