Ontogeny of Rem Sleep, Nrem Sleep and Awake State in the Human Fetus in Utero

在过去的三年里，我们一直在继续研究人类胎儿在子宫内的行为模式的个体发生，使用实时超声观察，与大脑功能的发展有关。因此，得到以下结果：1。胎儿眼动在妊娠16周左右可观察到，并有零星发生。在妊娠24-25周以后，眼动逐渐巩固，从而形成眼动期（REM）和非眼动期（NREM）。最迟在妊娠37 ~ 38周时，REM和NREM出现交替变化，持续时间几乎一致：分别为24分钟（平均值）和22分钟。当试图通过分段回归分析个体眼动的持续时间作为参数时，在妊娠33周及以上的胎儿中，注意到临界持续时间点为0.6-0.7秒，具有统计学意义。这一发现表明眼球运动有两种不同的类型：快速眼动和慢速眼动，从而揭示了子宫内存在快速眼动睡眠状态。在快速眼动睡眠期间，在300至525毫秒的大范围间隔内观察到随机的嘴部运动，与妊娠前期无关，而在妊娠35周之后，每300至600毫秒有规律的嘴部运动只与非快速眼动期同时发生。这为人类胎儿存在非快速眼动睡眠状态提供了证据。通过对瞳孔缩小与快速眼动期和非快速眼动期关系的研究发现，妊娠36-40周胎儿约有5%的检查期出现瞳孔缩小的特殊时期，发生在快速眼动期。因此，这一发现强烈表明，在宫内生活开始萌芽的清醒状态。我们相信我们的研究结果将朝着人类胎儿行为学迈出一步。

For the past 3 years, we have continued to make studies on ontogeny of behavioral patterns in the human fetus in utero, observed using a real-time ultrasound, in relation to the development of brain function.Consequently, the following findings were obtained :1. Fetal eye movement became observable at around 16 weeks of gestation with sporadic onset of occurrence. At 24-25 weeks of gestation onwards, the eye movement was found to gradually consolidate, thereby leading to formation of eye-movement (REM) and non eye-movement (NREM) periods. At the latest by 37-38 weeks of gestation, REM and NREM periods revealed an alternative change with almost uniform duration : 24 (mean value) and 22 minutes, respectively.2. When attempting to analyze the duration of the individual eye movement as a parameter by means of piecewise regression, the critical given duration point was noted, with statistical significance, at 0.6-0.7 second in the fetuses at 33 weeks of gestation or more. This finding demonstrates that there are two different types of eye movement : rapid and slow eye movements, thereby revealing the in utero existence of REM sleep state.3. Random mouthing movements occurring at a wide range of interval between 300 and 525 milliseconds were observed during REM sleep and were unrelated to advance in gestation, while regular mouthing every 300 to 600 milliseconds concurred only with NREM period at 35 weeks of gestation thereafter. This provides the evidence that there exists NREM sleep state in the human fetus.4. From study on relation between mydriasis/miosis and REM/NREM periods, it was evident that about 5% of examination period in the fetuses at 36-40 weeks of gestation was observed to show the special period with mydriasis occurring during REM period. Therefore, this finding strongly suggests a sprout of awake state beginning during intrauterine life.We believe our results will take a step toward human fetal ethology.