The Neural Basis for Reducing the Risk of Ambiguity in Sentence Processing

描述（由申请人提供）：在日常对话中，人们经常会遇到模棱两可的词。例如，“投手”可以指棒球运动员或水容器。然而，我们并不清楚说话者如何选择词语来减少歧义（例如，说“棒球运动员”而不是“投手”）。也不清楚当听众在对话中遇到一个模棱两可的词时，他们是如何选择解释的。在会话中最小化歧义的一个解释是基于词汇的：一种语言机制检测两个概念表示共享一个单词形式表示。我们假设词汇解释将由中颞叶皮层支持，该区域通常涉及概念和单词形式表征。另一种解释基于神经经济学：个人选择个人效用预期最高的词。在此上下文中，效用是指产生或理解歧义的风险与产生每个术语所需的资源之间的平衡。我们假设腹内侧前额叶（vmPFC）和下顶叶（IP）皮质也会支持这一神经经济学解释，它们通常与决策过程有关。本项目的总体目标是研究句子处理中歧义最小化的认知和神经基础。具体目标1将调查神经退行性疾病患者在句子制作过程中减少歧义的能力。我们将重点关注患有中颞叶皮层疾病的语义性痴呆，患有IP疾病的皮质基底变性，以及患有vmPFC疾病的额颞叶痴呆患者。具体目标2将通过对健康受试者的功能磁共振成像研究，在神经基础上获得最小化句子生成过程中歧义的收敛证据。我们预测，中颞叶、IP和vmPFC都将有助于减少歧义。具体目标3将研究在句子生成和句子理解过程中是否有类似的神经网络支持最小化歧义。了解句子处理中减少歧义的认知和神经基础将改善患者与护理者的沟通，提高患者的生活质量、护理质量和安全性。它还将有助于我们理解人类认知的一个关键但难以捉摸的特性的神经基础。

DESCRIPTION (provided by applicant): In daily conversation individuals regularly encounter ambiguous words. For example, "pitcher" could refer to a baseball player or a water container. However, it is not clear how speakers choose words to minimize ambiguities (e.g., saying "baseball player instead of "pitcher"). It also is not clear how listeners choose to interpret an ambiguous word when they are encountered in conversation. One account for minimizing ambiguity during conversation is lexically-based: a linguistic mechanism detects that two conceptual representations share a single word-form representation. We hypothesize the lexical account will be supported by middle temporal cortex, a region often implicated for conceptual and word-form representation. An alternative account is based on neuroeconomics: individuals choose the word with the highest expected individual utility. In this context utility refers to the balance between the risks associated with producing or comprehending an ambiguity and the resources required for producing each term. We hypothesize that the neuroeconomic account will be additionally supported by ventromedial prefrontal (vmPFC) and inferior parietal (IP) cortices, which are often implicated for decision-making processes. The overall aim of this project is to investigate the cognitive and neural basis for minimizing ambiguity in sentence processing. Specific Aim 1 will investigate neurodegenerative disease patients' abilities to minimize ambiguity during sentence production. We will focus on semantic dementia who have middle temporal cortex disease, corticobasal degeneration who have IP disease, and frontotemporal dementia patients who have vmPFC disease. Specific Aim 2 will obtain converging evidence on the neural basis for minimizing ambiguity during sentence production using fMRI studies of healthy subjects. We predict that middle temporal, IP, and vmPFC will all contribute to minimizing ambiguity. Specific Aim 3 will investigate whether minimizing ambiguity is supported by a similar neurological network during both sentence production and sentence comprehension. Understanding the cognitive and neural basis of minimizing ambiguity in sentence processing will improve patient-caregiver communication and yield an improved quality of life, care, and safety for patients. It will also contribute to our understanding of the neural basis for a crucial, but elusive, property of human cognition.