Investigation on the ontogenesis in fetal learning and behavior

在先前关于32 ~ 37孕周胎儿对重复振声刺激的防御反射（DR）适应的研究中，所有32 ~ 37孕周的胎儿都能适应。相比之下，妊娠32至34周的胎儿比妊娠35至37周的胎儿（观察到非快速眼动睡眠）需要更多的试验来显示习惯。本研究的目的是研究孕32至37周胎儿在重复低强度（85分贝）声音刺激下心率的发育变化。我们测量心率的幅度变化作为胎儿反应的指标。在妊娠35至37周时，大多数胎儿在第一次试验中表现出减速反应。振幅随着使用相同刺激的进一步试验而下降，然后在暴露于另一种刺激时恢复。相比之下，妊娠32至34周胎儿的反应在不同的试验中是不同的，并且在暴露于另一种刺激类型时没有恢复。我们的研究结果表明，胎儿心脏反应的习惯化随着发育年龄的变化而变化。并认为该方法可作为评价人类胎儿发育状况的更精细的参数。

In the previous study of fetal habituation of defensive reflex(DR)s to repeated vibro-acoustic stimulation at 32 to 37 weeks of gestation, all fetuses at 32 to 37 weeks of gestation were able to habituate. In contrast, fetuses at 32 to 34 weeks of gestation took significantly more trials to show habituation than fetuses at 35 to 37 weeks in whom non-REM sleep was observed.The aim of this study was to investigate developmental changes in heart rate response to repeated low-intensity (85 dB) sound stimulation in fetuses between 32 and 37 weeks of gestation. We measured amplitude changes in heart rate as our index of fetal response. At 35 to 37 weeks of gestation, the majority of fetuses showed a deceleratory response at the first trial. Amplitude decreased with further trials using the same stimulus before recovering when exposed to another type of stimulation. In contrast, responses in fetuses at 32 to 34 weeks of gestation were variable across trials and there was no recovery with exposure to another type of stimulation.Our results suggest that fetal habituation of cardiac response changes with developmental age. It is also assumed that this method can be more fine parameter to estimate the developmental status in the human fetus.