The neural basis of language comprehension: Insights from spatiotemporal imaging

为了在嘈杂和模棱两可的环境中成功理解语言，人脑必须使用 上下文信息，以主动预测即将到来的语言输入。自上而下预测中的缺陷是 被认为是导致各种神经发育障碍的语言和沟通障碍的原因， 从与阅读障碍相关的阅读障碍，到严重的社交和交际功能障碍 精神分裂症和自闭症谱系障碍的特征。在神经典型的成年人中，语言预测是 已知在左侧额颞部网络中调节神经活动。然而，人们对此知之甚少。 决定整个过程中前馈和反馈活动的时间的计算机制 网络。这项授权询问这些神经动力学是否可以通过预测编码来解释--一个统一的 知觉和认知功能理论。根据预测编码，大脑推断出 通过最小化大脑皮层层次的多个级别的预测误差来实现感官输入。为了验证这一理论， 这项拨款提出了一系列使用三种互补的神经成像技术的实验-- 脑磁图(MEG)、脑电(EEG)和功能磁共振成像(FMRI) 在语言理解过程中，神经活动对输入单词的时序和位置。计算型 使用已实施的语言处理预测编码模型的模拟将作为一种强大的 补充研究工具，允许测试明确的、基于计算的假设。目标 1(脑电/脑磁图)将检验诱发(锁相)神经的时间过程和定位的假设 左侧颞叶皮质内的活动可以用多个语言水平的预测误差来解释 代表权。目标2(MEG/EEG)将使用表征相似性分析来直接捕获神经前体 在预测性句子语境中，特定词语在不同语言表征水平上的激活。这些 这些方法也将被用来跟踪在单词之后收敛到锐化的神经表示的时间过程 在预测性和非预测性两种情况下开始。在这两个目标中，使用 同样的项目将与这些神经成像研究并行进行，以指导解释。目标 3(脑磁图/脑电/功能磁共振)询问动态预测编码框架的原理是否可以解释 大脑能够灵活地改变先前的预测，以便快速推断出新的潜在信息。 具体地说，这个目标是问这些原理是否能解释额叶最高水平的神经活动-- 时间语言层级--左下额叶皮质--以及对下皮质的自上而下反馈 各地区在后期处理阶段。通过直接将语言理解的神经生物学与中枢 人类皮质功能的理论，这个项目将确定核心神经和计算机制，可能 会被多种语言障碍所干扰。因此，它为开发有针对性的、 治疗和预防沟通障碍的理论动机神经认知策略。

For language comprehension to succeed in noisy and ambiguous environments, the human brain must use contextual information to actively predict upcoming linguistic inputs. Impairments in top-down prediction are thought to contribute to language and communicative dysfunction in a variety of neurodevelopmental disorders, from the reading disabilities associated with dyslexia, to the profound social and communicative dysfunctions that characterize schizophrenia and autism spectrum disorder. In neurotypical adults, linguistic prediction is known to modulate neural activity within a left-lateralized fronto-temporal network. However, little is known about the computational mechanisms that determine the timing of feedforward and feedback activity across this network. This grant asks whether these neural dynamics can be explained by predictive coding — a unifying theory of perceptual and cognitive function. According to predictive coding, the brain infers the meaning of sensory inputs by minimizing prediction error across multiple levels of the cortical hierarchy. To test this theory, this grant proposes a series of experiments using three complementary neuroimaging techniques –– magneto-encephalography (MEG), electroencephalography (EEG) and functional MRI –– to probe the timecourse and location of neural activity to incoming words during language comprehension. Computational simulations using an implemented predictive coding model of language processing will serve as a powerful complementary research tool, allowing for the testing of explicit, computationally motivated hypotheses. Aim 1 (EEG/MEG) will test the hypothesis that the timecourse and localization of evoked (phase-locked) neural activity within the left temporal cortex can be explained by prediction error at multiple levels of linguistic representation. Aim 2 (MEG/EEG) will use Representational Similarity Analysis to directly capture neural pre- activation of specific words at different levels of linguistic representation in predictive sentence contexts. These methods will also be used to track the timecourse of converging on sharpened neural representations after word onset in both predictive and non-predictive contexts. In both these Aims, computational simulations using the same items will proceed in parallel with these neuroimaging studies, guiding interpretation. Aim 3 (MEG/EEG/fMRI) asks whether the principles of dynamic predictive coding framework can explain how the brain is able to flexibly shift away from prior predictions in order to rapidly infer a new underlying message. Specifically, this Aim asks whether these principles can explain neural activity at the highest level of the fronto- temporal language hierarchy — the left inferior frontal cortex — as well as top-down feedback to lower cortical regions at a later stage of processing. By directly linking the neurobiology of language comprehension to a central theory of human cortical function, this project will identify core neural and computational mechanisms that may be disrupted in multiple language disorders. It therefore lays the foundation for the development of targeted, theoretically motivated neurocognitive strategies for the treatment and prevention of communicative disability.