University of Maryland, College Park, MD, USA.
National Institute of Child Health and Human Development, Bethesda, MD, USA.
Dev Sci. 2020 Nov;23(6):e12948. doi: 10.1111/desc.12948. Epub 2020 Mar 20.
The toddler and preschool years are a time of significant development in both expressive and receptive communication abilities. However, little is known about the neurobiological underpinnings of language development during this period, likely due to difficulties acquiring functional neuroimaging data. Functional near-infrared spectroscopy (fNIRS) is a motion-tolerant neuroimaging technique that assesses cortical brain activity and can be used in very young children. Here, we use fNIRS during perception of communicative and noncommunicative speech and gestures in typically developing 2- and 3-year-olds (Study 1, n = 15, n = 12 respectively) and in a sample of 2-year-olds with both fNIRS data collected at age 2 and language outcome data at age 3 (Study 2, n = 18). In Study 1, 2- and 3-year-olds differentiated between communicative and noncommunicative stimuli as well as between speech and gestures in the left lateral frontal region. However, 2-year-olds showed different patterns of activation from 3-year-olds in right medial frontal regions. In Study 2, which included two toddlers identified with early language delays along with 16 typically developing toddlers, neural differentiation of communicative stimuli in the right medial frontal region at age 2 predicted receptive language at age 3. Specifically, after accounting for variance related to verbal ability at age 2, increased neural activation for communicative gestures (vs. both communicative speech and noncommunicative gestures) at age 2 predicted higher receptive language scores at age 3. These results are discussed in the context of the underlying mechanisms of toddler language development and use of fNIRS in prediction of language outcomes.
学步儿和学龄前是表达和接受沟通能力显著发展的时期。然而，由于难以获得功能神经影像学数据，对于这段时期语言发展的神经生物学基础知之甚少。功能近红外光谱（fNIRS）是一种抗运动的神经影像学技术，可评估皮质脑活动，可用于非常年幼的儿童。在这里，我们在正常发育的 2 岁和 3 岁儿童（研究 1，n = 15，n = 12）以及 2 岁儿童中使用 fNIRS 进行研究，这些儿童在 2 岁时均采集了 fNIRS 数据，并且在 3 岁时具有语言结果数据（研究 2，n = 18）。在研究 1 中，2 岁和 3 岁的儿童在左侧额侧区分了交际性和非交际性刺激以及言语和手势。然而，2 岁的儿童在右内侧额区的激活模式与 3 岁的儿童不同。在研究 2 中，包括两名被诊断为早期语言迟缓的幼儿以及 16 名正常发育的幼儿，2 岁时右内侧额区交际性刺激的神经分化预测了 3 岁时的接受性语言。具体来说，在考虑了 2 岁时言语能力相关的方差后，2 岁时交际性手势（与交际性言语和非交际性手势相比）的神经激活增加预测了 3 岁时的接受性语言分数更高。这些结果在学步儿语言发展的潜在机制以及 fNIRS 在语言结果预测中的应用背景下进行了讨论。
