The neural basis of language comprehension: Insights from spatiotemporal imaging

描述（由申请人提供）：语言理解异常是许多神经发育和获得性障碍的特征，导致严重的社交障碍。这些疾病中的许多还表现为认知控制的执行缺陷，如冲突解决、选择、监测和适应。然而，我们对语言加工和认知控制之间的基本关系知之甚少。这项资助使用多模态神经成像技术来研究在健康成人中，调节语言理解和认知控制的神经系统如何、何时、何地相互作用。我们的基本假设是，只要有可能，我们就会使用上下文在多个层次上预测即将到来的信息，而且，当一个输入的单词与我们之前的部分或全部预测不一致时，我们就会花很长时间尝试将这个单词整合到它的上下文中。我们进一步假设，调节这种长期整合的神经机制与认知控制的核心机制密切相关，它们既取决于强度/确定性，也取决于我们先前预测的性质（词汇结构与事件结构）。最后，我们假设它们在使我们能够快速灵活地调整我们的理解机制以适应我们整体交际环境不断变化的需求方面发挥了重要作用。为了验证这些假设，我们提出了一系列实验，系统地操纵语言语境的约束和本质，并使用三种互补的神经成像技术——事件相关电位（ERPs）、功能磁共振成像（fMRI）和脑磁图（MEG）——来探测在这些语境中输入单词时大脑活动的时间和空间模式。在目标1中，我们探讨了检测和解决强、高确定性预测与违反该预测的输入词之间冲突的神经机制。在目标2中，我们探讨了选择与中等确定性预测匹配的输入词并抑制替代竞争预测的神经机制。在目标3中，我们询问不同的个体是否可以使用相同的上下文以不同的强度/确定性进行预测，导致一些人产生高冲突神经反应（见目标1），而另一些人则产生选择神经反应（见目标2）来整合相同的语言输入。我们还想知道，这些个体差异是否与行为表现和大脑活动有关，这些活动与执行任务有关，这些任务涉及更普遍的冲突控制机制（Stroop; AX-CPT）。最后，在目标4中，我们询问相同的个体是否可以通过以不同的优势/确定性进行预测来适应更广泛的交际环境，从而导致他们参与不同的神经机制（高冲突或选择反应）将相同的单词整合到相同的局部语境中。通过解决这些问题，该项目将确定核心神经机制，可以打破并导致多种不同疾病的理解缺陷。因此，它为有针对性的、理论上有动机的神经认知策略的发展奠定了基础，以预防和改善这些疾病中的沟通缺陷。

DESCRIPTION (provided by applicant): Abnormalities of language comprehension characterize many neurodevelopmental and acquired disorders, leading to severe social communicative dysfunction. Many of these same disorders are also characterized by executive deficits of cognitive control, such as conflict resolution, selection, monitoring and adaptation. Yt we know little about the basic relationships between language processing and cognitive control. This grant uses multimodal neuroimaging techniques to ask how, when and where the neural systems mediating language comprehension and cognitive control interact in healthy adults. Our basic hypothesis is that we use context whenever we can to predict upcoming information at multiple levels of representation, and that, when an incoming word disconfirms some or all of our prior prediction(s), we engage in prolonged attempts to integrate that word into its context. We further hypothesize that the neural mechanisms mediating this prolonged integration are closely linked to core mechanisms of cognitive control, and that they depend on both the strength/certainty as well as the nature of our prior predictions (lexical vs. event structure). Finally, we hypothesize that they play an essential role in enabling us to rapidly and flexibly adapt our comprehension mechanisms to the ever-changing demands of our overall communicative environment. To test these hypotheses, we propose a series of experiments that systematically manipulate both the constraint and the nature of linguistic context, and we use three complementary neuroimaging techniques--event-related potentials (ERPs), functional MRI (fMRI) and magneto-encephalography (MEG)--to probe the temporal and spatial patterns of brain activity recruited to incoming words in these contexts. Under Aim 1, we probe the neural mechanisms that detect and resolve conflict between a strong, high certainty prediction and an incoming word that violates this prediction. Under Aim 2, we probe the neural mechanisms that select an incoming word that matches a medium certainty prediction and suppress alternative competing prediction(s). Under Aim 3, we ask whether different individuals can use the same context to predict with different strengths/certainties, leading some people to mount a high conflict neural response (see Aim 1), and others to mount a selection neural response (see Aim 2) to integrate the same linguistic input. We also ask whether these individual differences can be linked to behavioral performance and brain activity associated with executive tasks that tap into more general conflict control mechanisms (Stroop; AX-CPT). Finally, under Aim 4, we ask whether the same individuals can adapt to their wider communicative environment by predicting with different strengths/certainties, leading them to engage different neural mechanisms (a high conflict or a selection response) to integrate the same word into the same local contexts. By addressing these questions, this project will identify core neural mechanisms that can break down and lead to comprehension deficits in multiple different disorders. It therefore lays the foundation for the development of targeted, theoretically motivated neurocognitive strategies to prevent and improve communication deficits in these disorders.