Sleep/wake transitions in sheep

Sleep disturbance is a common and disruptive symptom of neurodegenerative diseases such as Alzheimer’s and Huntington’s disease (HD). In HD patients, sleep fragmentation appears at an early stage of disease, although features of the earliest sleep abnormalities in presymptomatic HD are not fully established. Here we used novel automated analysis of quantitative electroencephalography to study transitions between wake and non-rapid eye movement sleep in a sheep model of presymptomatic HD. We found that while the number of transitions between sleep and wake were similar in normal and HD sheep, the dynamics of transitions from sleep-to-wake differed markedly between genotypes. Rather than the gradual changes in EEG power that occurs during transitioning from sleep-to-wake in normal sheep, transition into wake was abrupt in HD sheep. Furthermore, transitions to wake in normal sheep were preceded by a significant reduction in slow wave power, whereas in HD sheep this prior reduction in slow ...

睡眠障碍是阿尔茨海默病（Alzheimer’s）、亨廷顿舞蹈症（Huntington’s disease, HD）等神经退行性疾病常见且具有破坏性的临床症状。尽管症状前亨廷顿舞蹈症患者最早出现的睡眠异常特征尚未完全明确，但HD患者在疾病早期即会出现睡眠片段化现象。本研究采用新型定量脑电图（quantitative electroencephalography, qEEG）自动化分析方法，对症状前HD绵羊模型中觉醒与非快速眼动睡眠（non-rapid eye movement sleep, NREM睡眠）之间的转换状态进行了研究。研究发现，尽管正常绵羊与HD绵羊的睡眠-觉醒转换次数并无显著差异，但二者从睡眠转入觉醒的转换动力学特征存在显著的基因型差异。正常绵羊从睡眠转入觉醒时，脑电图功率会呈现渐进式变化；而HD绵羊的觉醒转换则表现为突发性。此外，正常绵羊在转入觉醒前，其慢波功率会出现显著下降；而在HD绵羊中，这种慢波功率的预先下降……