Laboratoire de Psychologie et Neuropsychologie Cognitives, CNRS-FRE 3292, Université Paris Descartes, Paris, France.
PLoS One. 2011 Feb 23;6(2):e17304. doi: 10.1371/journal.pone.0017304.
Human hearing develops progressively during the last trimester of gestation. Near-term fetuses can discriminate acoustic features, such as frequencies and spectra, and process complex auditory streams. Fetal and neonatal studies show that they can remember frequently recurring sounds. However, existing data can only show retention intervals up to several days after birth.
METHODOLOGY/PRINCIPAL FINDINGS: Here we show that auditory memories can last at least six weeks. Experimental fetuses were given precisely controlled exposure to a descending piano melody twice daily during the 35(th), 36(th), and 37(th) weeks of gestation. Six weeks later we assessed the cardiac responses of 25 exposed infants and 25 naive control infants, while in quiet sleep, to the descending melody and to an ascending control piano melody. The melodies had precisely inverse contours, but similar spectra, identical duration, tempo and rhythm, thus, almost identical amplitude envelopes. All infants displayed a significant heart rate change. In exposed infants, the descending melody evoked a cardiac deceleration that was twice larger than the decelerations elicited by the ascending melody and by both melodies in control infants.
CONCLUSIONS/SIGNIFICANCE: Thus, 3-weeks of prenatal exposure to a specific melodic contour affects infants 'auditory processing' or perception, i.e., impacts the autonomic nervous system at least six weeks later, when infants are 1-month old. Our results extend the retention interval over which a prenatally acquired memory of a specific sound stream can be observed from 3-4 days to six weeks. The long-term memory for the descending melody is interpreted in terms of enduring neurophysiological tuning and its significance for the developmental psychobiology of attention and perception, including early speech perception, is discussed.
人类的听力在妊娠末期逐渐发育。近足月胎儿可以辨别声音特征，如频率和频谱，并处理复杂的听觉流。胎儿和新生儿研究表明，他们可以记住经常重复的声音。然而，现有数据只能显示出生后几天的记忆保留时间。
方法/主要发现：在这里，我们展示了听觉记忆至少可以持续六周。实验胎儿在妊娠第 35、36 和 37 周期间每天接受两次精确控制的下降钢琴曲暴露。六周后，我们评估了 25 名暴露婴儿和 25 名天真对照组婴儿在安静睡眠时对下降旋律和上升控制钢琴旋律的心脏反应。这些旋律具有精确相反的轮廓，但具有相似的频谱、相同的持续时间、节奏和节奏，因此，振幅包络几乎相同。所有婴儿都显示出心率的显著变化。在暴露组婴儿中，下降旋律引起的心率减速是上升旋律和对照组婴儿中两个旋律引起的减速的两倍。
结论/意义：因此，3 周的产前暴露于特定旋律轮廓会影响婴儿的“听觉处理”或感知，即，至少在 6 周后，当婴儿 1 个月大时，会影响自主神经系统。我们的结果将特定声音流的产前获得的记忆的保留间隔从 3-4 天延长到 6 周。下降旋律的长期记忆被解释为持久的神经生理调谐，其对注意力和感知的发展心理生物学的意义，包括早期言语感知，将被讨论。
