Abstract

Introduction

Locus coeruleus (LC) is the major source of norepinephrine (NE) in the brain, which plays a key role in maintaining arousal and alertness. Sleep loss significantly impairs arousal and alertness. However, it is unknown whether sleep loss disrupts LC integrity, which can be measured non-invasively by diffusion tensor imaging (DTI). In the current study, we used DTI to examine the effects of one night of acute total sleep deprivation (TSD) on fractional anisotropy (FA), an index reflecting fiber density, axonal diameter and myelination.

Methods

We analyzed DTI and psychomotor vigilance test (PVT) data from N=54 health adults (23 females, age range 21–50 years) from a well controlled in-laboratory sleep deprivation study. Participants were randomized to either a TSD condition (n=40) without sleep on night 2, or a control condition (n=14) with no sleep loss. Standard DTI scans were conducted on the morning of day 2 and day 3 between 0700h-1000h. The PVT reciprocal response time (RRT) was used to measure individual’s response speed at baseline without sleep loss. LC regions-of-interest (ROI) were defined by standard templates from Keren et al. (2009). Imaging data were analyzed using FSL toolbox.

Results

For the whole TSD group, no differences were found in the LC FA values before and after sleep deprivation (p > .2). However, when dividing the TSD group to a slow group and a fast group based on their baseline PVT response speed, significantly increased LC FA were found in the slow group (p = .007) but not in the fast group (p > .4). The PVT RRT negatively correlated with LC FA value changes after TSD (r = -.44, p = .004). No correlations were found between the PVT RRT and LC FA changes in the control group.

Conclusion

Our results showed that baseline vigilance response speed correlated with LC integrity change after sleep deprivation, with slower response exhibiting greater changes in LC integrity. These findings support the key role of LC-NE system in the regulation of alertness and arousal.

Support

Supported in part by NIH grants R01-HL102119, R01-MH107571, R21-AG051981. CTRC UL1RR024134, and P30-NS045839.

中文翻译：

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0294基线响应速度预测睡眠剥夺后蓝斑完整性改变

摘要

介绍

蓝斑（LC）是大脑中去甲肾上腺素（NE）的主要来源，在维持唤醒和机敏性方面起着关键作用。睡眠不足会严重影响唤醒和机敏性。但是，尚不清楚睡眠丧失是否会破坏LC完整性，这可以通过扩散张量成像（DTI）进行无创测量。在当前的研究中，我们使用DTI来检查一整夜急性总睡眠剥夺（TSD）对分数各向异性（FA）的影响，分数是反映纤维密度，轴突直径和髓鞘形成的指数。

方法

我们对来自N = 54名健康成年人（23名女性，年龄范围21–50岁）的DTI和心理运动警惕性测试（PVT）数据进行了良好控制的实验室内睡眠剥夺研究的分析。参加者被随机分为TSD病情（n = 40），在第2晚没有睡眠，或对照组病情（n = 14），无睡眠障碍。在第2天和第3天早上0700h-1000h之间进行标准DTI扫描。PVT倒数响应时间（RRT）用于在基线无睡眠丧失的情况下测量个人的响应速度。LC感兴趣区域（ROI）由Keren等人的标准模板定义。（2009）。使用FSL工具箱分析成像数据。

结果

对于整个TSD组，剥夺睡眠前后的LC FA值均无差异（p > .2）。然而，基于他们的基线PVT响应速度除以TSD组为慢速组和快速组时，显著增加LC FA在慢组被发现（p = 0.007），但不是在快速组（p > 0.4 ）。在TSD之后，PVT RRT与LC FA值变化呈负相关（r = -.44，p = .004）。在对照组中，PVT RRT和LC FA变化之间没有相关性。

结论

我们的结果表明，基线警觉响应速度与睡眠剥夺后LC完整性变化相关，响应速度越慢，LC完整性变化越大。这些发现支持了LC-NE系统在警觉和唤醒调节中的关键作用。

支持

NIH赠款部分支持R01-HL102119，R01-MH107571，R21-AG051981。CTRC UL1RR024134和P30-NS045839。