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

描述(由申请者提供)：在日常对话中，个人经常会遇到歧义词语。例如，“Pitcher”可以指棒球运动员或水罐。然而，目前还不清楚发言者如何选择词语以尽量减少歧义(例如，说“棒球运动员”而不是“投手”)。当听众在对话中遇到一个模棱两可的单词时，他们如何选择解释也是不清楚的。减少对话中歧义的一种解释是基于词汇的：一种语言机制检测到两个概念表征共享一个词形表征。我们假设词汇账户将由中颞叶皮质支持，这是一个经常涉及概念和词形表征的区域。另一种解释基于神经经济学：个人选择具有最高预期个人效用的词。在这方面，效用是指与产生或理解歧义有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，神经经济学的解释还将受到腹内侧额叶(VmPFC)和顶叶下部(IP)皮质的支持，这两个皮质通常与决策过程有关。这个项目的总体目标是调查在句子处理中最大限度地减少歧义的认知和神经基础。具体目标1将调查神经退行性疾病患者在造句过程中尽量减少歧义的能力。我们将重点关注有中颞叶皮质疾病的语义性痴呆患者，有IP疾病的皮质基底膜变性患者，以及有vmPFC疾病的额颞痴呆患者。具体目标2将通过对健康受试者的功能磁共振研究，在减少句子产生过程中的歧义的神经基础上获得一致的证据。我们预测，中间时态、IP和vmPFC都将有助于最大限度地减少歧义。具体目标3将调查在句子产生和句子理解过程中，是否有相似的神经网络支持将歧义最小化。了解在句子处理过程中尽量减少歧义的认知和神经基础将改善患者与护理者的沟通，并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属性的神经基础。

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.