Neural Basis of Unilateral Spatial Neglect

单侧空间忽视的神经基础

• 批准号: 6820131
• 负责人: Argye E. Hillis
• 金额: $ 26.46万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6820131
• 关键词: acute disease /disorder; behavior test; behavioral /social science research tag; bioimaging /biomedical imaging; brain imaging /visualization /scanning; brain interhemispheric activity; cerebral ischemia /hypoxia; clinical research; functional magnetic resonance imaging; handedness; human subject; infarct; medical complication; neural information processing; perimetry; space perception; stroke; vision tests; visual fields; visual perception

DESCRIPTION (provided by applicant): Accumulating evidence from single cell recording studies in primates indicates that neurons encode spatial information in a variety of reference frames, which may be transformed to a single, common viewer (eye-) centered representation in posterior parietal cortex used for planning movements. Functional imaging studies also indicate that posterior parietal cortex is crucial for localization of objects in space (essential for planning saccades or reaching) in humans, whereas temporal cortex is crucial for object and word recognition. Lesions studies in both monkeys and humans indicate that spatial representations with different reference frames can occasionally be separately disrupted by brain damage, variously impairing action or perception on the side contralateral to the brain lesion (causing different forms of unilateral spatial neglect, or USN). However, the cortical organization of such spatial representations is fundamentally different in primates vs. humans, as indicated by the fact that lesions in either hemisphere cause comparable USN in monkeys, whereas right cortical lesions cause more common, severe, and persistent USN in humans. Conflicting results regarding the neural correlates of various types of USN in humans have been reported, which may be due to limitations of chronic lesion-deficit correlation studies. The goal of this project is to identify the nature and the neural basis of different types of USN with a novel approach utilizing MR perfusion weighted imaging (PWl) and diffusion weighted imaging (DWl), along with testing of USN at the same time, in subjects <24 hours post onset of stroke, and at three days after onset. This method complements functional imaging studies and avoids many of the pitfalls of chronic lesion-deficit studies. PWI shows regions of hypoperfused, dysfunctional tissue, while DWl reveals densely ischemic or infarcted tissue, in acute stroke. The major hypothesis is that PWl and DWl with concurrent USN testing can reveal areas of neural dysfunction, with or without structural damage, associated with USN in different reference frames or in different tasks, before substantial reorganization. It is further hypothesized that restoration of tissue function in a given region (by restoring regional blood flow) will result in resolution of specific types of USN. Results are expected to reveal distinct areas of cortex crucial for computing spatial representations with different reference frames, and to reveal mechanisms of USN in tasks with different purposes.

描述（申请人提供）：灵长类动物中单细胞记录研究的累积证据表明，神经元在各种参考框架中编码空间信息，这些信息可能会转变为用于计划运动的壁壁皮层中的单个公共观众（眼）中心表示。功能成像研究还表明，后顶叶皮层对于人类中的物体定位（对于计划扫视或触及至关重要）至关重要，而颞皮层对于物体和单词识别至关重要。在猴子和人类中的病变研究表明，具有不同参考框架的空间表示有时会因脑损伤而分别破坏与脑病变相反的侧面的动作或感知（引起不同形式的单侧空间忽视或USN）。然而，这种空间表示的皮质组织在灵长类动物与人类的根本上是不同的，这表明，任何一个半球的病变会在猴子中引起可比的USN，而正确的皮质病变会导致人类中更常见，更严重的USN。已经报道了有关人类各种USN神经相关性的矛盾结果，这可能是由于慢性病变缺陷相关研究的局限性。该项目的目的是使用MR灌注加权成像（PWL）和扩散加权成像（DWL）的新方法来识别不同类型的USN的性质和神经基础，同时在中风后<24小时对USN进行了测试，并在三天后进行。该方法补充了功能成像研究，并避免了许多慢性病变缺陷研究的陷阱。 PWI在急性中风中显示了垂体性，功能失调的组织的区域，而DWL揭示了密集的缺血性或梗塞组织。主要的假设是，带有USN测试的PWL和DWL可以揭示神经功能障碍的区域，无论有无结构性损害，在不同的参考框架或不同任务中与USN相关，然后进行实质性重组。进一步假设，在给定区域中组织功能的恢复（通过恢复区域血流）将导致特定类型的USN解决。预计结果将揭示对具有不同参考框架的空间表示的不同领域，并在具有不同目的的任务中揭示USN的机制。