Sensory and Motor Activity Development in the Human fetus

从对人类胎儿各种运动的相关性和并发性的研究来看，行为的生理发展明显可以与动物实验中看到的神经过程相媲美：1)关注人类个体发育，超昼夜节律(如眼动（EM)/无眼动（NEM）周期交替或胎心率（FHR）变化）的控制中心位于桥-延髓区，在妊娠30周左右开始发挥作用，足月时达到成熟。至于胎儿的昼夜节律，产生FHR变化的生物钟似乎在足月时受到母体环境因素的增强。2)关于人类胎儿的睡眠和清醒状态，在新生儿身上也发现了类似的运动相关性：在妊娠33周以后，慢眼动和快眼动同时存在，阴茎肿胀也与EM期有关，这表明快速眼动睡眠的生成中心在脑桥中发挥作用。在35周以后，与新动眼期同时进行的有规律的口部运动表明，这一阶段与非快速眼动睡眠相当，从而表明，负责非快速眼动睡眠的神经区域，从脑桥通过丘脑皮质通路到大脑半球，可能从妊娠35周开始发挥作用。所有这些发现都表明，即使在人类胎儿中，中枢神经系统功能也是按照这个顺序从尾侧到吻侧发育的。无头胎儿FHR变化的结果支持这一理论。足月胎儿瞳孔扩张与EM期密切相关，这为其与人类胎儿清醒状态的相关性提供了线索。3)初发期与足月排尿之间的时间关系可能是由于脑桥中这两种现象的控制部分在解剖学上接近，并在发育过程中相互作用。头位胎儿和臀位胎儿眼动方向的差异也是宫内生命的一个特征性现象，目前有待神经行为学的解释。4)通过评估胎儿足月的行为模式，可以在产前识别脑干病变或脑桥-延髓的尾侧病变，以及从上脑干扩散到大脑半球的弥漫性病变。如本研究所示，通过对正常胎儿行为发育过程数据的积累，可以检测出子宫内的各种异常运动，并了解这些异常与出生后中枢神经系统受损病变的关系。这些案例让人相信，它们是人类胎儿特定个体运动活动的表现与其相关的大脑功能之间匹配的模型。然而，通过观察行为来定位病变部位仅限于脑干，因为仍然存在一些问题需要澄清是否中枢Less

From this study on the correlation and concurrence of various movements in the human fetus, the physiological development of behavior is evident to be comparable to the neurological process as seen in the animal experiments : 1)Focusing on human ontogenesis, the controlling center of ultradian rhythm (such as eye movement (EM)/no-eye movement (NEM) period alternation or fetal heart rate (FHR) variation), lying in the ponto-medullar region, starts to function at around 30 weeks' gestation and reaches maturation at term. As for circadian rhythm in the fetus, the biological clock generating FHR change appears to be enhanced by maternal environmental factors at term. 2)With regard to the sleep and waking states in the human fetus, similar movement correlations have been made with neonates : Both slow eye movement coexisting with rapid eye movement at 33 weeks' gestation onwards, and penile tumescence relating to the EM period as well, suggest that the generating center of REM sleep in the … More pons is functioning. At 35 weeks onwards, regular mouthing movement concurrent with the NEM period indicates that this period is comparable to NREM sleep, thereby suggesting that the neural area, responsible for NREM sleep, from pons through the thalamocortical pathway to the cerebral hemisphere may begin to function from 35 weeks' gestation. All of these findings indicate that even in the human fetus, central nervous system function develops from the caudal to rostral segments, in that order. Findings from FHR changes in ancncephalic fetuses support this theory. In term fetuses, pupillary dilatation is closely related to the EM period, providing a clue to its correlation with waking states in the human fetus. 3) The temporal relationship between the onset of EM period and micturition at term may be interpreted by the anatomical proximity of control parts of both phenomena in the pons, interacting during the course of development. Difference in eye movement direction between cephalic and breech fetuses is also a characteristic phenomenon during intrauterine life, presently awaiting neuroethological explanation. 4) By assessing fetal behavioral patterns at term, it is possible to prenatally identify brainstem lesions at or caudal to the pons-medulla as well as diffuse lesions spreading from the upper brainstem to the cerebral hemispheres. As shown in this study, the accumulation of data on the developmental process of behavior in normal fetuses has enabled to detect various abnormal movements in utero, and also to comprehend these abnormalities in relation to impaired lesions in the cental nervous system after birth. These cases have led one to believe that they are the model of a match between the manifestation of a particular individual motor activity and its correlated brain function, in the human fetus. The localization of lesion sites by observation of behavior, however, is limited to the brainstem, as there still remain problems to be clucidated whether central Less