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，人们经常遇到模棱两可的话。例如，“投手”可以指棒球运动员或水容器。然而，目前还不清楚说话者如何选择单词以最大限度地减少歧义（例如，说“棒球运动员”而不是“投手”）。我们也不清楚当谈话中遇到一个模棱两可的词时，听众是如何选择解释这个词的。在会话中最小化歧义的一个解释是基于词汇的：语言学机制检测到两个概念表征共享一个单词形式表征。我们假设词汇帐户将支持颞叶中皮层，一个区域往往牵连的概念和单词形式的代表。另一种解释是基于神经经济学：个体选择具有最高预期个人效用的单词。在这种情况下，效用是指与产生或理解歧义相关的风险与产生每个术语所需的资源之间的平衡。我们假设，神经经济学帐户将额外支持腹内侧前额叶（vmPFC）和下顶叶（IP）皮质，这往往是牵连的决策过程。这个项目的总体目标是研究在句子处理中最小化歧义的认知和神经基础。具体目标1将研究神经退行性疾病患者在句子产生过程中最大限度地减少歧义的能力。我们将重点关注中颞叶皮质疾病的语义性痴呆、IP疾病的皮质基底节变性和VMPFC疾病的额颞叶痴呆患者。具体目标2将获得收敛的神经基础上的证据，最大限度地减少歧义，在句子生产使用功能磁共振成像研究健康受试者。我们预测，中间时间，IP和vmPFC都将有助于减少歧义。具体目标3将研究在句子产生和句子理解过程中，是否有类似的神经网络支持最小化歧义。理解句子处理中最小化歧义的认知和神经基础将改善患者与护理人员的沟通，并提高患者的生活质量，护理和安全。这也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.