Sensory and Motor Activity Development in the Human fetus

从这项关于人类胎儿各种运动的相关性和并发性的研究中，行为的生理发育明显类似于动物实验中所看到的神经过程：1)聚焦于人类个体发生，控制超常节奏(如眼动(EM)/无眼动(NEM)周期交替或胎儿心率(FHR)变化)的中心位于桥脑-延髓区域，在妊娠30周左右开始功能，并在足月达到成熟。至于胎儿的昼夜节律，产生胎心率变化的生物钟似乎在足月时被母亲的环境因素增强。2)对于胎儿的睡眠和清醒状态，新生儿也有类似的运动相关性：妊娠33周以后，慢眼球运动和快眼球运动并存，阴茎肿胀也与EM期有关，提示…中REM睡眠的产生中心更多的脑桥正在运作。在35周以后，与NEM期同时进行的有规律的张口运动表明，这一时期与NREM睡眠相当，从而表明负责NREM睡眠的神经区域从脑桥通过丘脑皮质途径到大脑半球可能从35周开始开始运作。所有这些发现表明，即使在人类胎儿中，中枢神经系统的功能也是按照从尾部到吻部的顺序发育的。头位胎儿胎心率变化的研究结果支持这一理论。在足月胎儿中，瞳孔扩张与EM期密切相关，为其与人类胎儿清醒状态的相关性提供了线索。3)EM期的开始和足月排尿之间的时间关系可以通过在发育过程中两种现象的控制部分在解剖学上的接近而相互作用来解释。头位和臀位胎儿眼球运动方向的差异也是宫内生活中的一种特征现象，目前尚待神经行为学解释。4)通过评估足月胎儿的行为模式，有可能在产前确定脑干病变位于脑桥或延髓尾侧，以及弥漫性病变从上脑干扩散到大脑半球。这项研究表明，正常胎儿行为发育过程的数据积累使人们能够发现宫内各种异常运动，并了解这些异常与出生后中枢神经系统受损的损害有关。这些案例让人相信，它们是特定个体运动活动的表现与其在人类胎儿中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，因为是否中枢减少仍有问题需要解决。

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