Doctoral Dissertation Research: Neural Bases of Semantic Composition in the Verb Phrase

自然语言语义的丰富性源于将元素组合在一起并从这些组合中派生出新含义的能力。理解这种能力一直是语言神经生物学和理论语言学的中心目标。然而，尽管研究迅速增长，大脑构成的基础充其量只是模糊的理解。在过去十年中，大多数的进展都局限于句子水平的一般描述，确定了一个用于句子意义组成的大脑区域网络，但没有进一步说明句子组成的各个方面是如何编码的。考虑到形式语义学的假设，即组合可以通过至少两种不同的规则发生，理解各种语言环境中非常基本的组合实例是表征句子解释的神经基础的重要的第一步。为此，本文采用自下而上的方法，以英语动词短语为重点，研究小组成单元的神经基质。解析一个动词的两种主要的构成方式，即修饰（例如，paint + slowly）和论证的饱和（例如，paint + slowly）。， paint + a picture)，本作品旨在回答一个复杂事件描述的意义，例如“John勉强画了一幅画”，是如何由各种事件元素组成的，即John (agent)，勉强（manner），油漆（action）和图片（object）。这项工作旨在为完整句子组成的计算详细表征奠定关键基础。本论文包括三个研究，利用脑磁图的高时空分辨率来表征成分的动态。第一个实验研究了修饰在言语领域的神经特征，询问动词及其修饰语的组合如何影响大脑，以及这种整体模式与名词-修饰语组合的模式相比如何，后者在先前的工作中已经描述了稳定的结果。第二个实验研究了事件域概念特异性的神经表征。先前的文献表明，大脑的一个特定区域，即左前颞叶（LATL），对物体域（例如，船与独木舟）的概念特异性很敏感。在询问事件特异性是否也以同样的方式涉及同一区域时，第二个实验操纵了事件的概念特异性（例如，“囤积燃料”与“储存燃料”）。最后一个实验探讨了合成词不构成句法成分的（可能的）语义组合情况。总之，这些研究结合了理论语言学和心理学文献关于概念和类别的见解，阐明了动词短语解释中表现出来的事件构成的神经反射。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The richness of natural language semantics stems from the ability to compose elements together and to derive novel meanings from these combinations. Understanding this ability has been a central goal in the neurobiology of language, as well as in theoretical linguistics. However, despite a rapidly growing body of research, the brain basis of composition has been vaguely understood at best. Most of the progress during the last decade has been limited to general descriptions of the sentence level, identifying a network of brain areas recruited for the composition of sentential meaning but not further specifying how the individual facets of sentence composition are encoded. Considering the assumption in formal semantics that composition can happen via at least two different rules, understanding very basic instances of composition in various linguistic environments is an essential first step for characterizing the neural basis of sentence interpretation. To this end, this dissertation takes a bottom-up approach, investigating neural substrates of small units of composition, with its focus on English verb phrases. Disentangling the two major modes of composition around a verb, namely modification (e.g., paint + slowly) and saturation of arguments (e,g., paint + a picture), this work aims to provide an answer to the question of how the meaning of a complex event description, e.g., "John reluctantly painted a picture," is composed from the various event elements, i.e., John (agent), reluctantly (manner), painted (action), and a picture (object). This work aims to lay a critical foundation for a computationally detailed characterization of full sentence composition. This dissertation consists of three studies that take advantage of the high spatiotemporal resolution of magnetoencephalography to characterize the dynamics of composition. The first experiment investigates the neural signatures of modification in the verbal domain, asking how the combination of a verb and its modifier engages the brain, and how this overall pattern compares to that of noun-modifier combination, for which stable results have been described in prior work. The second experiment investigates the neural representation of conceptual specificity in the event domain. Previous literature has shown that a particular brain region, the left anterior temporal lobe (LATL), is sensitive to conceptual specificity in the object domain (e.g., boat vs. canoe). Asking whether event specificity also involves the same area in the same way, the second experiment manipulates the conceptual specificity of events (e.g., "hoard fuel" vs "store fuel"). The last experiment explores situations of (possible) semantic composition in which the combining words do not form a syntactic constituent. In all, these studies combine insights from theoretical linguistics and from the psychological literature on concepts and categories to elucidate the neural reflexes of event composition as manifested in verb phrase interpretation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.