The Role of Feature Diagnosticity in Semantic Memory

描述（由申请人提供）：拟议研究的最终目标是更好地了解语义记忆组织和存储的神经机制。阐明语义记忆的发展和组织仍然是认知神经科学中的一个关键问题，各种理论试图捕捉日常物体的概念表征到其神经相关物的映射。一个流行的语义记忆模型表明，分布式对象表征对应于特定于模态的感觉运动脑区。许多行为学、神经心理学和神经影像学研究都支持这一模型，但关于不同的感官体验如何帮助塑造对物体的长期记忆，这仍然是一个悬而未决的问题。具体而言，特征诊断性可能在形成对象的表征结构的丰富性方面发挥重要作用。该方案试图通过训练受试者对一组新的物体进行训练，从而建立对物体的控制表征，来研究经验和记忆之间的关系。受试者将学习一组颜色和形状都是诊断特征的物体，或者只有形状是诊断特征的物体。在实验1中，我将通过一个物体识别任务来考察新物体表征中的行为变化。我还将看到这些变化是如何作为学习风格的函数而变化的。实验2提供了一个直接的测试（通过传统的单变量分析）的神经相关的功能诊断采用神经成像（fMRI），以调查如何诊断功能改变神经表征的学习对象。在这里，诊断功能在多大程度上调节负责感知这些功能的大脑区域的活动将被检查。实验3探讨行为（多维缩放）和神经（多体素模式分析）表示的相似性空间和梯度的新学习的对象，预测显着的相关性，在负责感知诊断功能的大脑区域的两个表示。该建议探讨了特征诊断性在经验和知识的相互作用中的作用，以阐明视觉知识组织的神经基础，并有助于理解语义知识缺陷的性质。概念知识的缺陷与几种疾病有关，包括阿尔茨海默病和额颞叶痴呆症。更深入地了解概念知识的组织和存储背后的神经基础，将使我们能够更好地理解特定概念知识缺陷的表现，这反过来又会为患者的治疗提供信息。

DESCRIPTION (provided by applicant): The ultimate goal of the proposed research is to better understand the neural mechanisms underlying organization and storage of semantic memory. Elucidating the development and organization of semantic memory remains a critical problem in cognitive neuroscience, and various theories attempt to capture the mapping of conceptual representations for everyday objects onto their neural correlates. One prevalent model of semantic memory suggests that distributed object representations correspond to modality-specific sensorimotor brain areas. Numerous behavioral, neuropsychological, and neuroimaging studies have supported this model, but it remains an open question as to how varied sensory experience helps to shape long-term memory of objects. Specifically, feature diagnosticity may play an important role in forming the richness of an object's representational structure. This proposal seeks to investigate the relationship between experience and memory by training subjects on a set of novel objects, thus building controlled representations of the objects. Subjects will either learn a set of objects for which both color and shape are diagnostic, or for which only shape is a diagnostic feature. In Experiment 1,1 will examine behavioral changes in novel object representations through an object recognition task. I will also see how these changes vary as a function of learning style. Experiment 2 offers a direct test (through traditional univariate analyses) for neural correlates of feature diagnosticity by employing neuroimaging (fMRI) to investigate how diagnostic features alter neural representations of learned objects. Here, the extent to which diagnostic features modulate activity in brain regions responsible for perception of these features will be examined. Experiment 3 probes behavioral (multidimensional scaling) and neural (multi-voxel pattern analysis) representations of the similarity space and gradient of the newly learned objects, predicting significant correlations for the two representations in brain regions responsible for perceiving the diagnostic features. This proposal explores the role of feature diagnosticity in interactions of experience and knowledge to both shed light on the neural bases for visual knowledge organization and aid in understanding the nature of semantic knowledge deficits. Deficits in conceptual knowledge are associated with several disorders, including Alzheimer's Disease and Frontotemporal Dementia. A deeper knowledge of the neural bases underlying the organization and storage of conceptual knowledge will allow us to better understand the manifestation of specific conceptual knowledge deficits, which will in turn yield insight in informing patient treatments.