GRAMFc, Inserm U 1105, Centre Universitaire de Recherches en Santé, CHU sud, Avenue Laennec, 80036 Amiens Cedex, France.
GRAMFc, Inserm U 1105, Centre Universitaire de Recherches en Santé, CHU sud, Avenue Laennec, 80036 Amiens Cedex, France.
Neuroimage. 2023 Dec 15;284:120428. doi: 10.1016/j.neuroimage.2023.120428. Epub 2023 Oct 27.
During the last trimester of gestation, fetuses and preterm neonates begin to respond to sensory stimulation and to discover the structure of their environment. Yet, neuronal migration is still ongoing. This late migration notably concerns the supra-granular layers neurons, which are believed to play a critical role in encoding predictions and detecting regularities. In order to gain a deeper understanding of how the brain processes and perceives regularities during this stage of development, we conducted a study in which we recorded event-related potentials (ERP) in 31-wGA preterm and full-term neonates exposed to alternating auditory sequences (e.g. "ba ga ba ga ba"), when the regularity of these sequences was violated by a repetition (e.g., ``ba ga ba ga ga''). We compared the ERPs in this case to those obtained when violating a simple repetition pattern ("ga ga ga ga ga" vs. "ga ga ga ga ba"). Our results indicated that both preterm and full-term neonates were able to detect violations of regularity in both types of sequences, indicating that as early as 31 weeks gestational age, human neonates are sensitive to the conditional statistics between successive auditory elements. Full-term neonates showed an early and similar mismatch response (MMR) in the repetition and alternating sequences. In contrast, 31-wGA neonates exhibited a two-component MMR. The first component which was only observed for simple sequences with repetition, corresponded to sensory adaptation. It was followed much later by a deviance-detection component that was observed for both alternation and repetition sequences. This pattern confirms that MMRs detected at the scalp may correspond to a dual cortical process and shows that deviance detection computed by higher-level regions accelerates dramatically with brain maturation during the last weeks of gestation to become indistinguishable from bottom-up sensory adaptation at term.
在妊娠的最后三个月，胎儿和早产儿开始对感觉刺激做出反应，并开始发现周围环境的结构。然而，神经元迁移仍在继续。这种晚期迁移主要涉及超颗粒层神经元，这些神经元被认为在编码预测和检测规则方面起着关键作用。为了更深入地了解大脑在这个发育阶段如何处理和感知规则，我们进行了一项研究，在这项研究中，我们记录了 31 周胎龄和足月新生儿在暴露于交替听觉序列（例如“ba ga ba ga ba”）时的事件相关电位（ERP），当这些序列的规则被重复（例如，“ba ga ba ga ga”）破坏时。我们将这种情况下的 ERP 与违反简单重复模式（“ga ga ga ga ga”与“ga ga ga ga ba”）时获得的 ERP 进行了比较。我们的结果表明，早产儿和足月新生儿都能够检测到两种类型序列中规则的违反，这表明早在 31 周妊娠龄时，人类新生儿对连续听觉元素之间的条件统计就很敏感。足月新生儿在重复和交替序列中均表现出早期且相似的失匹配反应（MMR）。相比之下，31 周胎龄的新生儿表现出双成分 MMR。仅在具有重复的简单序列中观察到的第一个成分对应于感觉适应。随后，在观察到交替和重复序列的情况下，出现了一个偏差检测成分。这种模式证实，头皮上检测到的 MMR 可能对应于双皮质过程，并表明，通过更高层次区域计算的偏差检测随着妊娠最后几周大脑的成熟而急剧加速，以至于在足月时与自下而上的感觉适应无法区分。
