Neural Basis of Generalized Quantifers

描述(申请人提供)：语义记忆在交流和思维中起着关键作用，但语义记忆的认知和神经基础方面的进展已被证明是难以捉摸的。我们提出了一种新的语义记忆方法，通过关注“一些苹果”和“大多数橙子”这样的广义量词来实现。我们的广义量词理解模型至少包括一个表示数字知识的有限简单电路集，一个保存中间计算结果的工作记忆装置，以及一个处理工作记忆中保存的信息的小组合操作集。我们将这个语义域映射到一个大规模的神经网络上，该网络至少包括顶叶皮质(用于数字知识)、下额叶皮质(用于工作记忆)和背外侧前额叶皮质(用于执行切换)。初步的计算工作，对健康老年人和局灶性神经退行性疾病患者的行为研究，以及功能神经成像工作支持这些区别。皮质基底区变性患者在数字知识方面存在基本缺陷，但几乎没有其他词汇理解困难，这与顶叶萎缩有关。他们对“一阶量词”的理解能力尤其受损，比如“一些X”，这些词主要依赖于数字知识；健康成年人的fMRI研究将对一阶量词的理解与顶叶皮质联系起来。额颞痴呆和阿尔茨海默病患者的工作记忆有限，转换能力差，这与额叶萎缩有关。健康成年人的fMRI工作将高阶量词的理解与额叶皮质联系起来，他们对高阶量词的理解受到了损害，例如，除了数字知识外，高阶量词的理解也需要工作记忆和对工作记忆中保留的信息的处理。我们建议在健康的老年人和患有这些神经退行性疾病的患者中进行更多的建模、行为和功能神经成像研究，以确定数字知识、工作记忆和执行转换在广义量词理解过程中的认知和神经贡献。这些研究的结果将为语义记忆的神经基础提供一个新的重要视角，并将提高痴呆症患者的诊断和预后准确性。

DESCRIPTION (provided by applicant): Semantic memory plays a critical role in communication and thought, but advances in the cognitive and neural basis for semantic memory have proven elusive. We propose a novel approach to semantic memory by focusing on generalized quantifiers like "some of the apples" and "most of the oranges." Our model of generalized quantifier comprehension includes at least a finite set of simple circuits that represent number knowledge, a working memory device the retains the results of intermediate computations, and a small set of combinatorial operations that manipulate information held in working memory. We map this semantic domain onto a large-scale neural network that includes at least parietal cortex (for number knowledge), inferior frontal cortex (for working memory), and dorsolateral prefrontal cortex (for executive switching). Preliminary computational work, behavioral studies in healthy seniors and patients with focal neurodegenerative diseases, and functional neuroimaging work support these distinctions. Patients with corticobasal degeneration have a fundamental deficit in number knowledge but little other lexical comprehension difficulty, related to parietal atrophy. They are particularly impaired in their comprehension of "first-order quantifiers" like "some of the X" that depend crucially on number knowledge; fMRI work in healthy adults relates comprehension of first-order quantifiers to parietal cortex. Frontotemporal dementia and Alzheimer's disease patients have limited working memory and poor switching that are associated with frontal atrophy. They are impaired in their comprehension of "higher-order quantifiers" like "most of the X" that, beyond number knowledge, also require working memory and the manipulation of information retained in working memory, fMRI work in healthy adults relates comprehension of higher-order quantifiers to frontal cortex. We propose additional modeling, behavioral, and functional neuroimaging studies in healthy seniors and patients with these neurodegenerative diseases to establish the cognitive and neural contribution of number knowledge, working memory, and executive switching during generalized quantifier comprehension. The results of these studies will provide a novel and important perspective on the neural basis for semantic memory, and will improve diagnostic and prognostic accuracy in patients suffering from dementia.