Investigation on the ontogenesis in fetal learning and behavior

在早先关于胎儿防御反射(DR)习惯化的研究中，S在孕32~37周对重复振声刺激的习惯性研究中，所有孕32~37周的胎儿都能习服。相反，胎龄32-34周的胎儿表现习惯化的次数明显多于胎龄35-37周的胎儿，在胎龄35-37周的胎儿观察到非快速眼动睡眠。本研究的目的是研究胎龄32-37周的胎儿对重复低强度(85分贝)声音刺激的心率反应的发育变化。我们测量了心率的幅度变化作为胎儿反应的指标。在怀孕35到37周时，大多数胎儿在第一次试验中表现出减速反应。随着使用相同刺激的进一步试验，幅度降低，然后在暴露于另一种类型的刺激时恢复。相反，胎儿在怀孕32到34周时的反应在不同的试验中是不同的，暴露在另一种类型的刺激下没有恢复。我们的结果表明，胎儿对心脏反应的习惯性随着发育年龄的变化而改变。并认为该方法可以作为更精细的参数来估计胎儿的发育状况。

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.