Abstract: Background  Working for long hours often leads to mental fatigue. There is evidence that mental fatigue is serious damage to cognitive function and behavior of the operator. Revealing the mechanism of continuous operation and sleep deprivation (SD) on cognitive function, will help to combat the fatigue caused by continuous operation and to improve capacity of operators. This functional magnetic resonance imaging (fMRI) study focused on the influence of sleep deprivation on digital memory in human brain. Methods Totally 6 healthy subjects underwent a digital memory encoding, maintenance and retrieval session during fMRI scanning before and after 48 h sleep deprivation. Results  The digital memory test had the same error rate before and after sleep deprivation (P > 0.05, for all), but the reponse time of seven-number memory was longer after sleep deprivation (P = 0.005). During encoding trials decreased fMRI regions of significant activation between sleep control and sleep deprivation were in left parahippocampal gyrus Brodmann 30, left superior temporal gyrus Brodmann 42, left insular lobe Brodmann 41 and left frontal lobe Brodmann 6. During maintenance trials decreased fMRI regions of significant activation were at left superior temporal gyrus Brodmann 38, left middle temporal gyrus Brodmann 21, left parahippocampus and amygdaloid nucleus Brodmann 30, left middle frontal gyrus Brodmann 47, left lenticular nucleus and thalamus, right lenticular nucleus, left retrosplenial granular cortex Brodmann 30, right retrosplenial granular cortex Brodmann 30, bilateral cingulate gyrus Brodmann 24 and bilateral middle frontal gyrus, medial frontal gyrus Brodmann 6. During retrieval trials decreased fMRI regions of significantly positive activation were at bilateral hippocampus, right amygdaloid nucleus and inferior parietal lobule Brodmann 40, left precuneus Brodmann 19 and thalamus. Conclusion  Different brain regions are activated at different stages of the digital memory to keep awake after sleep deprivation. The cerebral cortical and subcortical structures participated digital memory will be injured after 48 h of sleep deprivation.

Key words: Sleep deprivation, Memory, Magnetic resonance imaging, Neuropsychological tests

摘要： 研究背景 长时间连续作业易导致大脑疲劳，已有证据显示脑疲劳对作业者认知功能和行为反应能力具有严重损害作用，因此揭示连续作业和睡眠剥夺对认知功能影响的机制，有助于对抗连续作业所致疲劳，提高连续作业能力。本研究通过分析睡眠剥夺前后功能磁共振成像（fMRI）特点，探讨睡眠剥夺影响学习记忆的神经机制。方法 共6 例健康男性志愿者接受48 h 睡眠剥夺，采用组块设计方法评价睡眠剥夺前后数字记忆功能变化，fMRI 比较数字记忆编码、维持和提取阶段各脑区的激活特点。结果 睡眠剥夺48 h，受试者对4 ~ 7 个0 ~ 9 数字记忆的错误率并未增加（均P > 0.05）；对4 ~ 6 个0 ~ 9 数字记忆的反应时间与睡眠剥夺前无明显差异（均P > 0.05），仅7 个0 ~ 9 数字记忆的反应时间增加（P = 0.005）。睡眠剥夺后激活减弱的脑区在数字记忆试验编码阶段为左侧海马旁回Brodmann 30 区、颞上回Brodmann 42 区、岛叶Brodmann 41 区和额叶Brodmann 6 区；在维持阶段分别为左侧颞上回Brodmann 38 区、颞中回Brodmann 21 区、海马旁回和杏仁核Brodmann 30 区、额中回Brodmann 47 区、豆状核和丘脑，以及右侧豆状核、左侧扣带后回Brodmann 30 区、右侧扣带后回Brodmann 30 区、双侧扣带回Brodmann 24 区、双侧额中回和额内侧回Brodmann 6 区；提取阶段包括双侧海马、右侧杏仁核和顶下小叶Brodmann 40 区、左侧楔前叶Brodmann 19 区和丘脑。结论 在数字记忆的不同阶段，机体通过激活不同的脑区来维持清醒状态，48 h睡眠剥夺后参与数字记忆的大脑皮质及皮质下结构广泛受损。

关键词: 睡眠剥夺, 记忆, 磁共振成像, 神经心理学测验