Investigation on the ontogenesis in fetal learning and behavior.

本研究的目的是：1)用习惯化和经典条件反射评价胎儿的学习能力；2)阐明胎儿发育过程中其他行为与胎儿学习的关系；3)将胎儿学习应用于临床评价胎儿中枢神经系统功能。我们调查了胎儿对振动声刺激(VAS)的习惯性。至少从怀孕32周开始，胎儿就表现出了习惯性。此外，即使在相同的胎龄，从行为角度来看，发育较差的胎儿比发育较好的胎儿要经历更多的尝试才能实现习惯化。综合这些数据，证明了行为发展的方方面面与习惯化之间存在一定的关系。接下来，我们测试了使用经典的条件化治疗，人类胎儿是否可以在宫外音和VAS之间形成联系。使用两种纯音作为条件刺激，一种是在500赫兹的音调之后总是跟随80赫兹的VAS，即无条件刺激(US)，另一种是在1000赫兹的音调之后从来没有VAS。这些结果表明，行为发育和习服能力之间存在关系，即中枢神经系统发育和习服之间存在关系。应考虑将该技术应用于中枢神经系统异常的评估。

In this study, we aimed 1) to evaluate learning ability of the human fetus using the habituation and classical conditioning, 2) to clarify relationship between other behaviors and fetal learning in development, and 3) to adopt fetal learning to clinical evaluation in human fetus central nervous system function.We divided 26 fetuses at 32-37 weeks of gestation into 3 groups using combined criteria of gestational age and behavioral indicators. We investigated fetal habituation to vibroacoustic stimulation (VAS). Fetuses showed habituation from at least 32 weeks of gestation. Furthermore, fetuses less developed from behavioral standpoint took significantly more trials to achieve habituation than developed fetuses even in the same gestational age. Taken together with these data, it was proved that there was a relationship between aspects of behavioral development and habituation. Next, we tested whether a human fetus could form an association between an extrauterine tone and VAS using classical conditioning treatment. Two kinds of pure tone were used as the conditioned stimuli, one where a 500-Hz tone was always followed by a VAS of 80 Hz, the unconditioned stimulus (US), and another where a 1000-Hz tone was never followed by a VAS. In 3 human infants did not show significant response to either tone.These results indicating that there was a relationship between behavioral development and ability to habituate, that is, between the CNS development and habituation. The application of this technique to the evaluation of CNS abnormality should be considered.