Saadatmehr Bahar, Edalati Mohammadreza, Wallois Fabrice, Ghostine Ghida, Kongolo Guy, Flaten Erica, Tillmann Barbara, Trainor Laurel, Moghimi Sahar
Inserm UMR1105, Groupe de Recherches sur l'Analyse Multimodale de la Fonction Cérébrale, CURS, Amiens Cedex 80036, France.
Inserm UMR1105, EFSN Pédiatriques, CHU Amiens sud, Amiens Cedex 80054, France.
J Neurosci. 2025 Jan 22;45(4):e0398242024. doi: 10.1523/JNEUROSCI.0398-24.2024.
Rhythm perception and synchronization to periodicity hold fundamental neurodevelopmental importance for language acquisition, musical behavior, and social communication. Rhythm is omnipresent in the fetal auditory world and newborns demonstrate sensitivity to auditory rhythmic cues. During the last trimester of gestation, the brain begins to respond to auditory stimulation and to code the auditory environment. When and how during this period do the neural capacities for rhythm processing develop? We conducted a cross-sectional study in 46 neonates (24 male) born between 27 and 35 weeks gestational age (wGA), measuring their neural responses to auditory rhythms with high-density electroencephalography during sleep. We developed measures to evaluate neural synchronization to nested rhythmic periodicities, including the fast isochronous beat and slower metrical (beat grouping) structures. We show that neural synchronization to beat and meter becomes stronger with increasing GA, converging on small phase differences between stimulus and neural responses near term, similar to those observed in adults. Dividing the cohort into subpopulations born before and after 33 wGA revealed that both younger and older groups showed neural synchronization to the fast periodicity related to the isochronous beat, whereas only the older group showed significant neural synchronization to the slower meter frequencies related to beat groupings, suggesting that encoding of nested periodicities arrives during late gestation. Together, our results shed light on the rapid evolution of neural coding of external hierarchical auditory rhythms during the third trimester of gestation, starting from the age when the thalamocortical axons establish the first synapses with the cortical plate.
节奏感知以及与周期性同步对于语言习得、音乐行为和社交沟通具有重要的神经发育意义。节奏在胎儿的听觉世界中无处不在，新生儿对听觉节奏线索表现出敏感性。在妊娠晚期，大脑开始对听觉刺激做出反应并对听觉环境进行编码。在这个时期，节奏处理的神经能力何时以及如何发展？我们对46名胎龄在27至35周（wGA）之间出生的新生儿（24名男性）进行了一项横断面研究，在睡眠期间用高密度脑电图测量他们对听觉节奏的神经反应。我们开发了一些测量方法来评估与嵌套节奏周期性的神经同步，包括快速等时节拍和较慢的节拍（节拍分组）结构。我们发现，随着胎龄增加，与节拍和节拍组的神经同步变得更强，在足月时刺激与神经反应之间的相位差逐渐缩小，类似于在成年人中观察到的情况。将队列分为33 wGA之前和之后出生的亚组，结果显示较年轻和较年长的组都表现出与等时节拍相关的快速周期性的神经同步，而只有较年长的组表现出与节拍分组相关的较慢节拍频率的显著神经同步，这表明嵌套周期性的编码在妊娠晚期出现。总之，我们的研究结果揭示了妊娠晚期从丘脑皮质轴突与皮质板建立第一个突触开始时，外部层次听觉节奏神经编码的快速演变。
