MODULATION OF CIRCADIAN RHYTHMICITY IN PRETERM INFANTS

许多早产儿居住数周或数月的环境 出生后的环境与子宫内的环境明显不同。 热量、荷尔蒙和其他有节奏和有模式的母体输入， 通常赋予发育中的胎儿的， 新生儿重症监护室（NICU）持续照明、嘈杂的环境。 关于人的昼夜节律性的发展知之甚少， 生理变量，如温度，心肺控制， 早产儿的活动和睡眠。 同样，目前还不清楚 NICU环境影响节律性活动。 此外，时间越长- 幼儿园环境对睡眠质量，喂养，生长， 以及早产儿生理和行为的其他方面， 不太了解。 在解决这些问题时，建议采取多学科方法 它检查神经解剖学、环境、生理和行为 婴儿昼夜节律系统的各个方面。 第一，发展 神经元通路介导光对下丘脑的影响 视交叉上核（SCN），假定的“生物钟”将是 研究，提供了关于神经元成熟的第一个数据， 人类婴儿昼夜节律系统的组成部分。 二、NICU灯 环境将从时间生物学的角度进行量化， 允许与大量关于光的影响的文献进行比较， 生物节律 第三，外显节奏性的发展， 温度、心率和活动将在一个频谱上进行描述 使用强大的分析电池， 技术. 呼吸暂停和周期性呼吸，这与 婴儿猝死综合症（SIDS）的风险增加， 发病率，也将在多日期间进行测量，以提供新的数据 可能的周期性变化的特征， 控制 最后，利用斯坦福大学医学中心的早产儿研究， 中心作为一个受控的环境，其即时和长期的影响 光暗循环对节律性事件的出现和睡眠的影响 得到考验 对婴儿昼夜节律个体发育的认识 将有助于新生儿评估，干预，管理， 优化NICU的物理环境和简化程序。 这些研究的结果将提供科学依据， 改善新生儿重症监护室环境，促进康复， 发展，并改善这一重要的婴儿群体的结果。

The environment in which many premature infants reside for weeks or months after birth differs markedly from the surroundings encountered in utero. Thermal, hormonal, and other rhythmic and patterned maternal inputs which are normally conferred on the developing fetus are replaced by the constantly lit, noisy milieu of the neonatal intensive care unit (NICU). Very little is known about the development of circadian rhythmicity of physiological variables such as temperature, cardiorespiratory control, activity, and sleep in preterm infants. Similarly, it is unclear how the NICU environment influences rhythmic activity. In addition, the longer- term effects of nursery environments on sleep quality, feeding, growth, and other aspects of the physiology and behavior of preterm infants are poorly understood. In addressing these questions, a multidisciplinary approach is proposed which examines neuroanatomical, environmental, physiologic, and behavior aspects of the infant circadian system. First, the development of the neuronal pathway mediating the effects of light on the hypothalamic suprachiasmatic nucleus (SCN), the putative "biological clock" will be examined, providing the first data on the maturation of the neuronal components of the human infant circadian system. Second, the NICU light environment will be quantified from a chronobiological perspective, permitting comparison with a vast literature on the influences of light on biological rhythms. Third, the development of overt rhythmicity of temperature, heart rate, and activity will be described across a spectrum of gestational and postnatal ages using a powerful battery of analytical techniques. Apnea and periodic breathing, which have been linked with increased risk for Sudden Infant Death Syndrome (SIDS) and increased morbidity, will also be measured over multiday periods to provide new data on possible cyclic alterations in the characteristics of respiratory control. Finally, using Stanford Medical Center's Premature Research Center as a controlled environment, the immediate and longer-term effects of light-dark cycling on the appearance of rhythmic events and sleep will be tested. Awareness of the ontogeny of circadian rhythmicity in infants will be helpful in neonatal assessment, intervention, management, and in optimizing the physical environment and caregiving procedures in the NICU. Results from these studies will provide a scientific basis for the refinement of the NICU environment and facilitate the recovery, development, and improved outcome in this significant infant population.