Department of Psychology, The University of Chicago, Illinois, USA.
Department of Neurology, University of California, Irvine, Irvine, California, USA.
Dev Sci. 2018 Sep;21(5):e12648. doi: 10.1111/desc.12648. Epub 2018 Mar 8.
Gesture is an integral part of children's communicative repertoire. However, little is known about the neurobiology of speech and gesture integration in the developing brain. We investigated how 8- to 10-year-old children processed gesture that was essential to understanding a set of narratives. We asked whether the functional neuroanatomy of gesture-speech integration varies as a function of (1) the content of speech, and/or (2) individual differences in how gesture is processed. When gestures provided missing information not present in the speech (i.e., disambiguating gesture; e.g., "pet" + flapping palms = bird), the presence of gesture led to increased activity in inferior frontal gyri, the right middle temporal gyrus, and the left superior temporal gyrus, compared to when gesture provided redundant information (i.e., reinforcing gesture; e.g., "bird" + flapping palms = bird). This pattern of activation was found only in children who were able to successfully integrate gesture and speech behaviorally, as indicated by their performance on post-test story comprehension questions. Children who did not glean meaning from gesture did not show differential activation across the two conditions. Our results suggest that the brain activation pattern for gesture-speech integration in children overlaps with-but is broader than-the pattern in adults performing the same task. Overall, our results provide a possible neurobiological mechanism that could underlie children's increasing ability to integrate gesture and speech over childhood, and account for individual differences in that integration.
手势是儿童交际手段的一个组成部分。然而，对于发展中的大脑中言语和手势整合的神经生物学知之甚少。我们研究了 8 至 10 岁的儿童如何处理理解一系列叙事所需的手势。我们想知道手势-言语整合的功能神经解剖结构是否会随着以下因素而变化：（1）言语的内容，和/或（2）手势处理的个体差异。当手势提供了言语中没有的缺失信息（即，有区别的手势；例如，“pet”+拍打手掌=鸟）时，与手势提供冗余信息（即，强化手势；例如，“bird”+拍打手掌=鸟）相比，手势的存在会导致下额叶回、右中颞回和左颞上回的活动增加。这种激活模式仅在那些能够成功地将手势和言语整合到行为中的儿童中发现，这从他们在测试后故事理解问题上的表现就可以看出。那些不能从手势中理解意义的儿童在两种情况下没有表现出不同的激活。我们的结果表明，儿童手势-言语整合的大脑激活模式与成人执行相同任务的模式重叠，但范围更广。总的来说，我们的研究结果提供了一个可能的神经生物学机制，它可以解释儿童在整个童年时期不断增强的手势和言语整合能力，并解释这种整合的个体差异。
