Spatiotemporal Imaging of Semantic Memory

描述(申请者提供)：申请重点是神经科 语义记忆的基础，这是人类对世界的认识。 在过去的二十年里，有许多文章描述了 脑损伤/疾病患者的特定类别缺陷。这些 赤字涉及一种或多种知识的选择性退化。 例如，一些患者表现出对动物知识的丧失，但不是 工具，而其他人则相反。在20世纪90年代，杰出的神经成像 使用正电子发射计算机断层扫描和功能磁共振成像的研究显示了特定类别的大脑模式 健康受试者的激活。这两组发现加在一起，有 引发了关于病毒的性质和起源的争论(但没有明确的答案) 特定类别的效果。此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研究 从128个密集阵列记录的事件相关脑电位(ERPs) 用新方法对电极进行分析以定位污染源 头皮记录的大脑中的电活动与核磁共振共同记录。这个 基本观点是，为了理解这两个领域的特定类别效应 患者和非患者人群，重要的是要确定哪些部分 大脑实际上代表的是语义信息。的静态图像 大脑中参与处理不同类别的 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来 对此信息的其他操作。为了本地化语义表示，它 是将产生此信息的访问机制与 代理网站。这可以使用ERPS来完成，因为卓越的 这项技术的时间分辨率使人们能够专注于神经活动 在加工的早期时间窗口期间，在该时间窗口期间 占主导地位。使用新技术，这些机制可以分析和 定位在大脑中。建议的研究涉及应用这种方法。 涉及多个语义记忆范例，以便提供时空 有助于解释神经成像/神经心理学研究的信息。 此外，该项目将利用这些成果为制定 语义记忆的联结主义吸引子模型。隔离、本地化和 从理论上讲，语义表示和访问的特征应该有助于 语义记忆障碍的认识与诊断 建议可能的治疗方法。

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.