Department of Experimental Clinical and Health Psychology, Ghent University, Belgium; ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Spain.
Integrative Neuroscience and Cognition Center (INCC), CNRS and University of Paris, France; Department of Developmental and Social Psychology, University of Padua, Italy.
Infant Behav Dev. 2022 May;67:101724. doi: 10.1016/j.infbeh.2022.101724. Epub 2022 May 28.
Language acquisition in the first year of life plays an important role in human development. Although recent research has increased our knowledge of early language development, the origins and developmental trajectories of language processing during infancy are still being debated. One important issue is whether the infant brain has already developed adult-like functional cortical specialization and lateralization for speech and language processing. Although a relatively large number of previous studies have investigated the cortical specialization for speech processing in newborns by comparing responses to normal speech with responses to time-reversed speech as a control, the subsequent development of this differential response is less well understood. In the current study, our primary goal was, therefore, to expand our knowledge of functional specialization for speech during the first year of life. By using functional near-infrared spectroscopy (fNIRS), we examined the hemodynamic responses in the temporal cortex to forward-going speech in the native language, Dutch, and backward Dutch in seventy-eight infants aged 5 and 10 months. We observed that five-month-old infants show bilateral activation to both forward and backward speech without obvious hemispheric lateralization for language, while ten-month-old infants show greater left-lateralized inverted responses (e.g., reduction in oxyhaemoglobin and increase in deoxyhaemoglobin) to forward speech than to backward speech. Overall, our findings indicate that the neural correlates of language processing undergo developmental changes in the first year of life.
生命第一年的语言习得在人类发展中起着重要作用。尽管最近的研究增加了我们对早期语言发展的了解，但婴儿期语言处理的起源和发展轨迹仍在争论之中。一个重要的问题是，婴儿的大脑是否已经发展出成人般的、针对言语和语言处理的功能皮质特化和侧化。尽管之前有相当多的研究通过比较正常言语和时间反转言语的反应来研究新生儿对言语处理的皮质特化，但对这种差异反应的后续发展了解较少。因此，在当前的研究中，我们的主要目标是扩展我们对生命第一年中言语功能特化的知识。通过使用功能性近红外光谱（fNIRS），我们检查了 78 名 5 个月和 10 个月大的婴儿颞叶皮质对母语荷兰语的正向言语和逆向荷兰语的血流动力学反应。我们观察到，5 个月大的婴儿对正向和逆向言语都表现出双侧激活，而没有明显的语言半球侧化，而 10 个月大的婴儿对正向言语的倒置反应（例如，氧合血红蛋白减少和脱氧血红蛋白增加）比逆向言语更大。总的来说，我们的发现表明，语言处理的神经相关性在生命的第一年发生了发展变化。
