Beniaich Younes, Farsi Hicham, M'hani Mohammed El Mehdi, Piro Mohammed, Achaâban Mohamed Rachid, Challet Etienne, Pévet Paul, Satté Amal, El Allali Khalid
Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute, Rabat, Morocco.
Medicine and Surgical Unit of Domestic Animals, Department of Medicine, Surgery and Reproduction, Hassan II Agronomy and Veterinary Medicine Institute, Rabat, Morocco.
J Sleep Res. 2025 Jun;34(3):e14377. doi: 10.1111/jsr.14377. Epub 2024 Oct 21.
The 'first night effect' (FNE) is a well-known phenomenon in polysomnographic (PSG) sleep studies, resulting in significant variations in the macrostructure of wakefulness and sleep states, particularly between the initial and subsequent sleep recording sessions. The FNE phenomenon during sleep has been studied in various species, revealing complex variations between several sessions of sleep recording. The present study used a non-invasive PSG method to examine differences between various vigilance states in four adult female dromedary camels during 4 consecutive nights and days of sleep recording. The results indicate the presence of a FNE in the architecture of the dromedary camel's vigilance states. On the first night, the proportions of wakefulness and light non-rapid eye movment (NREM) sleep (drowsiness) were higher, at a mean (standard error of the mean [SEM]) of 40.92% (0.88%) and 14.93% (0.37%), respectively; while the proportion of rumination (mean [SEM] 29.55% [0.92%]) was lower compared to consecutive nights. No FNE was found on deep NREM sleep, while night-time REM sleep had a shorter proportion during the first night compared to subsequent consecutive nights. A significantly lower REM/total sleep time (TST) ratio was observed on the first night. Daytime comparisons did not show any significant differences for the different vigilance states. The increase in wakefulness and light NREM sleep and the reduction in REM sleep and REM/TST sleep on the first night indicate a decline in sleep quality in the dromedary camel due to the FNE. Thus, we recommend excluding from a PSG sleep study at least the first session/night of the recordings to ensure accurate results.
“首夜效应”（FNE）是多导睡眠图（PSG）睡眠研究中一个广为人知的现象，它会导致清醒和睡眠状态的宏观结构出现显著变化，尤其是在首次和后续睡眠记录时段之间。睡眠期间的首夜效应现象已在多种物种中得到研究，揭示了多次睡眠记录时段之间的复杂变化。本研究采用非侵入性PSG方法，在连续4个昼夜的睡眠记录中，检查了4只成年雌性单峰骆驼在不同警觉状态下的差异。结果表明，单峰骆驼的警觉状态结构中存在首夜效应。在第一晚，清醒和浅度非快速眼动（NREM）睡眠（困倦）的比例较高，平均（平均标准误差[SEM]）分别为40.92%（0.88%）和14.93%（0.37%）；而反刍的比例（平均[SEM] 29.55%[0.92%]）与连续的夜晚相比更低。在深度NREM睡眠中未发现首夜效应，而与随后连续的夜晚相比，第一晚夜间快速眼动（REM）睡眠的比例较短。在第一晚观察到REM/总睡眠时间（TST）比率显著较低。白天不同警觉状态的比较未显示任何显著差异。第一晚清醒和浅度NREM睡眠的增加以及REM睡眠和REM/TST睡眠的减少表明，由于首夜效应，单峰骆驼的睡眠质量下降。因此，我们建议在PSG睡眠研究中至少排除记录的第一时段/夜晚，以确保结果准确。
