Spatiotemporal Imaging of Semantic Memory

描述（由申请人提供）：该应用程序侧重于神经 语义记忆是人类对世界的认识。 在过去的二十年里，一些文章描述了 大脑受损/患病患者的类别特异性缺陷。这些 缺陷涉及一个或多个知识类别的选择性退化。 例如，一些患者表现出对动物的知识丧失，但 工具，而其他人则相反。在20世纪90年代，突出的神经成像 使用PET和fMRI的研究表明， 在健康受试者中激活。总之，这两组发现 引发了关于其性质和起源的争论（但没有明确的答案）。 特定类别效应。本应用程序通过以下方式解决此问题： 用数据补充现有的神经心理学和神经影像学研究 从事件相关脑电位（ERP）记录的128个密集阵列， 用新方法分析电极， 头皮记录的脑电活动与核磁共振成像记录一致。的 基本思想是，为了理解两种情况下的类别特异性效应， 患者和非患者人群，重要的是要确定哪些部分 大脑实际上是在表达语义信息。的静态图像 大脑中负责处理不同种类的 语义知识不足以确定关键存储位置， 因为这样的神经心理学和神经影像学证据并不容易 将代表信息的区域与稍后执行的区域区分开， 对这些信息的其他操作。为了本地化语义表示， 必须将产生此信息的访问机制与 代表性的网站。这可以通过ERP来实现，因为 这种技术的时间分辨率允许人们专注于神经活动 在处理的早期时间窗口期间， 占主导地位。使用新技术，可以分析这些机制， 定位在大脑中。拟议的研究涉及应用这种方法 到一些语义记忆范例，以提供时空 有助于解释神经影像学/神经心理学研究的信息。 此外，该项目还将利用这些结果为制定 语义记忆的联结吸引模型隔离、定位和 从理论上描述语义表示和访问应该有助于 理解和诊断语义记忆障碍，并应 可能的治疗方法。

DESCRIPTION (provided by applicant): The application focuses on the neural substrates of semantic memory, which is a human's knowledge of the world. During the last two decades, a number of articles have described category-specific deficits in patients with damaged/diseased brains. These deficits involve selective degradation of one or more categories of knowledge. For instance, some patients exhibit loss of knowledge of animals, but not tools, while others show the reverse. During the 1990s, prominent neuroimaging studies using PET and fMRI have shown category-specific patterns of brain activation in healthy subjects. Together, these two sets of findings have spurred debate (but no definitive answers) regarding the nature and origin of category-specific effects. This application tackles this question by supplementing extant neuropsychological and neuroimaging research with data from event-related brain potentials (ERPs) recorded with a dense array of 128 electrodes analyzed with new methods for localizing the sources of scalp-recorded electrical activity in the brain co-registered with MRI. The basic idea is that in order to understand category-specific effects in both patient and nonpatient populations, it is important to determine what parts of the brain are actually representing semantic information. Static images of the parts of the brain that are involved in processing different categories of semantic knowledge are insufficient for determining the critical storage sites, because such neuropsychological and neuroimaging evidence does not easily distinguish areas that represent the information from areas that later perform other operations on this information. To localize semantic representation, it is necessary to isolate the access mechanisms that yield this information from the representation sites. This can be done using ERPs, because the superb temporal resolution of this technique allows one to focus on neural activity during the early time-window of processing during which semantic access predominates. Using new technologies, these mechanisms can be analyzed and localized in the brain. The proposed research involves applying this approach to a number of semantic memory paradigms in order to provide spatiotemporal information to help interpret neuroimaging/neuropsychological studies. Furthermore, the project will use such results to inform the development of connectionist attractor models of semantic memory. Isolating, localizing, and theoretically characterizing semantic representation and access should help in the understanding and diagnosis of disorders of semantic memory and should suggest possible therapies.