The neural basis of language comprehension: Insights from spatiotemporal imaging

描述(申请人提供)：语言理解的异常表现为许多神经发育和获得性障碍，导致严重的社交功能障碍。这些障碍中的许多还以认知控制的执行缺陷为特征，如冲突解决、选择、监控和适应。我们对语言处理和认知控制之间的基本关系知之甚少。这项资助使用多模式神经成像技术来研究健康成年人中调节语言理解和认知控制的神经系统如何、何时和在哪里相互作用。我们的基本假设是，只要有可能，我们就会使用上下文来预测即将到来的信息在多个表征水平上，并且，当一个进入的单词与我们之前的预测的部分或全部不一致时(S)，我们会进行长期的尝试，试图将该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，它们既取决于我们先前预测的强度/确定性，也取决于我们先前预测的性质(词汇与事件结构)。最后，我们假设它们在使我们能够快速而灵活地调整我们的理解机制以适应我们整个交际环境不断变化的需求方面发挥着至关重要的作用。为了验证这些假说，我们提出了一系列实验，系统地操纵语言语境的限制和性质，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)--探索在这些语境中大脑活动招募到输入单词的时间和空间模式。在目标1下，我们探索检测和解决强、高确定性预测与违反这一预测的输入单词之间的冲突的神经机制。在目标2下，我们探索了选择一个与中等确定性预测匹配的输入单词并抑制替代竞争预测的神经机制(S)。在目标3下，我们询问不同的人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，从而导致一些人安装高度冲突的神经反应(参见目标1)，而另一些人则安装选择性神经反应(参见目标2)以整合相同的语言输入。我们还询问，这些个体差异是否与利用更一般的冲突控制机制(Stroop；AX-CPT)的执行任务相关的行为表现和大脑活动有关。最后，在目标4下，我们询问相同的个体是否可以通过以不同的强度/确定性进行预测来适应他们更广泛的交际环境，从而导致他们使用不同的神经机制(高冲突或选择反应)来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，这个项目将确定核心神经机制，这些机制可以在多种不同的障碍中分解并导致理解缺陷。因此，它为开发有针对性的、理论上有动机的神经认知策略奠定了基础，以预防和改善这些障碍中的沟通障碍。

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.