Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.
Elizabeth Garrett Anderson Obstetric Wing, University College London Hospitals, London, United Kingdom.
Sleep. 2018 Aug 1;41(8). doi: 10.1093/sleep/zsy096.
Cortical activity patterns develop rapidly over the equivalent of the last trimester of gestation, in parallel with the establishment of sleep architecture. However, the emergence of mature cortical activity in wakefulness compared with sleep states in healthy preterm infants is poorly understood.
To investigate whether the cortical activity has a different developmental profile in each sleep-wake state, we recorded 11-channels electroencephalography (EEG), electrooculography (EOG), and respiratory movement for 1 hr from 115 infants 34 to 43 weeks-corrected age, with 0.5-17 days of postnatal age. We characterized the trajectory of δ, θ, and α-β oscillations in wakefulness, rapid eye movement (REM) sleep, and non-REM sleep by calculating the power spectrum of the EEG, averaged across artifact-free epochs.
δ-Oscillations in wakefulness and REM sleep decrease with corrected age, particularly in the temporal region, but not in non-REM sleep. θ-Oscillations increase with corrected age in sleep, especially non-REM sleep, but not in wakefulness. On the other hand, α-β oscillations decrease predominantly with postnatal age, independently of sleep-wake state, particularly in the occipital region.
The developmental trajectory of δ and θ rhythms is state-dependent and results in changed cortical activity patterns between states with corrected age, which suggests that these frequency bands may have particular functional roles in each state. Interestingly, postnatal age is associated with a decrease in α-β oscillations overlying primary visual cortex in every sleep-wake state, suggesting that postnatal experience (including the first visual input through open eyes during periods of wakefulness) is associated with resting-state visual cortical activity changes.
皮质活动模式在相当于妊娠末期的时间内迅速发展，与睡眠结构的建立并行。然而，与健康早产儿的睡眠状态相比，清醒状态下成熟皮质活动的出现仍知之甚少。
为了研究皮质活动在每个睡眠-觉醒状态下是否具有不同的发展特征，我们对 115 名校正胎龄 34 至 43 周、出生后 0.5 至 17 天的婴儿进行了 11 通道脑电图（EEG）、眼动电图（EOG）和呼吸运动记录，时长 1 小时。我们通过计算 EEG 的功率谱，在无伪迹的时段内进行平均，来描述清醒、快速眼动（REM）睡眠和非 REM 睡眠中的 δ、θ 和 α-β 振荡的轨迹。
清醒和 REM 睡眠中的 δ 振荡随校正胎龄而降低，尤其是在颞区，但非 REM 睡眠中则不然。θ 振荡随睡眠中（尤其是非 REM 睡眠）的校正胎龄而增加，但在清醒中则不然。另一方面，α-β 振荡主要随出生后年龄而降低，与睡眠-觉醒状态无关，尤其是在枕区。
δ 和 θ 节律的发展轨迹是状态依赖的，这导致了在不同的状态下皮质活动模式的改变，这表明这些频率带可能在每个状态中具有特定的功能作用。有趣的是，出生后年龄与每个睡眠-觉醒状态中覆盖初级视觉皮层的 α-β 振荡的减少有关，这表明出生后经验（包括在清醒期睁开眼睛接受的第一次视觉输入）与静息状态视觉皮层活动的变化有关。
