Studies on the ontogeny of the biological clock in the human fetus

本研究项目的目的是从生物钟个体发育的角度阐明人类胎儿在子宫内的超昼夜节律和昼夜节律的发育过程。结果表明：（1）超昼夜节律的控制中心（见于眼动/无眼动周期交替或胎心率变化）位于脑桥延髓区，在妊娠30周左右开始发挥作用，并在足月时达到成熟。 (2)就人类胎儿的睡眠和清醒状态而言，妊娠33周以后慢眼动与快速眼动并存，以及与眼动期相关的阴茎肿胀，表明脑桥的快速眼动睡眠生成中枢正在发挥作用。 (3)妊娠35周以后，有规律的张嘴运动和无眼球运动期同时发生，表明该时期与NREM睡眠相当，从而表明负责NREM睡眠的神经中枢，从脑桥通过丘脑皮质通路到达大脑半球可能在妊娠35周左右开始发挥作用。 (4) 眼动期的开始和足月排尿之间​​的时间关系可以通过脑桥中两种现象的控制部分的解剖学接近性以及它们在发育过程中的相互作用来解释。 (5) 胎儿胃动最迟在妊娠27周时出现两种不同的情况，并从29周起开始显现。从妊娠 31 周开始，这些状况的时间变化分为“活跃”和“安静”阶段。 (6) 使用最大熵功率谱分析，足月时的眼动模式显示出具有 16-29 小时的周期性。

The aim of this research project is to elucidate the developmental process of ultradian and circadian rhythms in the human fetus in utero, from the view point of the ontogeny of the biological clock.It was evident that : (1) The controlling center of ultradian rhythm (seen in eye movement / no eye movement period alternation or FHR variation), lying in the ponto-medullar region, starts to function at around 30 weeks' gestation and reaches maturation at term. (2) With regard to the sleep and waking states in the human fetus, both slow eye movement coexisting with rapid eye movement at 33 weeks' gestation onwards, and penile tumescence relating to the eye movement period as well, suggest that the generating center of REM sleep in the pons is functioning. (3) At 35 weeks' gestation onwards, regular mouthing movement concurrent with the no eye movement period indicates that this period is comparable to NREM sleep, thereby suggesting that the neural center, responsible for NREM sleep, from the pons through the thalamocortical pathway to the cerebral hemisphere may begin to function at around 35 weeks' gestation. (4) The temporal relationship between the onset of the eye movement period and micturition at term may be interpreted by the anatomical proximity of the controlling parts of both phenomena in the pons, and their interaction during the course of development. (5) Two different conditions emerge from fetal stomach movement, at the latest at 27 weeks' gestation, and begin manifesting from 29 weeks' onwards. The chronological changes in these conditions cluster into 'active' and 'quiet' phases from 31 weeks' gestation onwards. (6) Using maximum entropy power spectral analysis, the eye movement pattern at term was revealed to have a 16-29 hour periodicity.