Christiansen Taylor G, Sokoloff Greta, Long Hailey C, Kopp Olivia K, Karr Lydia K, Blumberg Mark S
Department of Psychological and Brain Sciences,University of Iowa, Psychological and Brain Sciences Building, 340 Iowa Ave, Iowa City, Iowa 52242.
Iowa Neuroscience Institute, University of Iowa, Psychological and Brain Sciences Building, 340 Iowa Ave, Iowa City, Iowa 52242.
bioRxiv. 2025 Jul 27:2025.07.23.666445. doi: 10.1101/2025.07.23.666445.
Twitches are discrete movements that characterize REM sleep. However, recent work showed that twitches also occur during NREM sleep in human infants beginning around 3 months of age, a time when sleep spindles and the cortical delta rhythm are also emerging. Further, NREM twitches co-occur with sleep spindles, suggesting a unique functional role. Given that NREM sleep is composed of distinct substages, we investigated whether twitching and twitch-spindle coupling are differentially expressed during N2 and N3 sleep. In 6-month-old human infants (n=21; 7 females), we recorded EEG, respiration, and video during daytime sleep. We found that the high intensity of twitching during N2 resembled REM more than N3. In contrast, sleep spindles exhibited similar temporal characteristics during N2 and N3. Also, despite differences in the intensity of twitching during N2 and N3, significant twitch-spindle coupling occurred in both stages. Finally, twitch rate was inversely related to delta power across NREM periods. These findings suggest that although twitching occurs during REM, N2, and N3 sleep at this age, its expression is compatible with some sleep components (e.g., rapid eye movements, sleep spindles) but not others (e.g., cortical delta), highlighting the continuing need to better understand the dynamic organization of sleep and its individual components in early development.
抽动是快速眼动睡眠（REM睡眠）的典型离散运动。然而，最近的研究表明，在大约3个月大的人类婴儿的非快速眼动睡眠（NREM睡眠）期间也会出现抽动，而这一时期睡眠纺锤波和皮层δ节律也开始出现。此外，NREM睡眠期的抽动与睡眠纺锤波同时出现，表明其具有独特的功能作用。鉴于NREM睡眠由不同的子阶段组成，我们研究了在N2和N3睡眠期间抽动和抽动-纺锤波耦合是否存在差异表达。在6个月大的人类婴儿（n = 21；7名女性）中，我们记录了白天睡眠期间的脑电图（EEG）、呼吸和视频。我们发现，N2睡眠期的高强度抽动与REM睡眠期更相似，而非N3睡眠期。相比之下，N2和N3睡眠期的睡眠纺锤波表现出相似的时间特征。此外，尽管N2和N3睡眠期的抽动强度存在差异，但在两个阶段均出现了显著的抽动-纺锤波耦合。最后，在整个NREM睡眠期，抽动频率与δ波功率呈负相关。这些发现表明，尽管在这个年龄段的REM、N2和N3睡眠期都会出现抽动，但其表现与某些睡眠成分（如快速眼动、睡眠纺锤波）相符，而与其他成分（如皮层δ波）不符，这凸显了在早期发育过程中持续深入了解睡眠及其各个成分动态组织的必要性。
