BEHAVIORAL AND SPECT ACTIVATION ANALYSIS OF HEMINEGLECT

我们建议分析中风患者的视觉空间功能障碍。 通过将临床缺陷与地形图相关联进行半侧切除 单光子发射断层扫描(SPECT)的激活模式。A两个 阶段研究将采用专门的主成分分析 由发起人之一开发，用于提取SPECT激活模式 与特定任务相关。第一阶段的研究将延长我们的 SPECT检查对半身板成分性质的研究 正常受试者线对分和线对分激活模式的研究 信件注销。这两种常用的半横切检测方法有 我们的实验室已经证明，患者是可分离的，这取决于 关于损伤的位置。第二阶段的研究将集中于 半身不化的知觉方面。在一个由三部分组成的实验中，我们将 检验一个经过充分测试的视觉空间知觉心理物理模型 这表明，左脑在基于范畴的判断上更具优势 评估(例如，点是在线上还是线下？)鉴于右翼 半球在基于坐标的评估方面更好(例如，是一条线 在其真实中点的2毫米范围内横切？)直截了当与 基于坐标的任务将用于SPECT激活。在实验中 1我们将分析两者在激活模式上的差异 正常对照中的任务类型。在实验2中，我们将分析 中使用同一对激活任务的激活模式 半全切患者，首先是他们疾病的急性期和 然后在6个月后，当半身不全改善时。我们期待着 急性期的SPECT模式将反映患者的 功能障碍的临床状态和激活模式将 随着临床功能恢复，随着时间的推移而改变。在实验3中，我们将 实验性偏瘫患者视空间功能障碍的探讨 通过系统地改变试验条件。相应的更改 在任务中的表现将与SPECT和 与未出现的患者的激活模式进行比较 通过行为干预和正常的激活模式 控制。我们将尝试证明实验操作 改善临床表现还系统地改变rCBF模式， 在视觉空间系统中反映可塑性。通过组合 具有更新成像和数据分析的实验行为方法 技术，我们有机会将功能成像数据添加到 基于临床观察的脑功能模型 脑损伤患者和正常人的心理物理数据。 虽然我们选择半脑切除作为研究脑损伤的模型， 所获得的知识和先进的技术可能会改变我们的思维方式 关于大脑对损伤的反应。

We propose to analyze visual-spatial dysfunction in stroke patients with hemineglect by correlating clinical deficits with topographical activation patterns on Single Photon Emission Tomography (SPECT). A two phase study will use a specialized Principle Components Analysis developed by one of the sponsors to extract SPECT activation patterns related to specific tasks. The first phase of the study will extend our research on the component nature of hemineglect by examining the SPECT activation patterns of normal subjects engaging in line bisection and letter cancellation. These two commonly used tests for hemineglect have been shown by our laboratory to be dissociable in patients, depending on lesion location. The second phase of the study will focus on the perceptual aspects of hemineglect. In a three-part experiment we will examine a well-tested psychophysical model of visual-spatial perception that states that the left hemisphere is superior in categorical-based assessments (e.g. Is a dot above or below a line?) whereas the right hemisphere is superior in coordinate-based assessments (e.g. Is a line transected within 2 mm of its true midpoint?). Categorical versus coordinate-based tasks will be used for SPECT activation. In experiment 1 we will analyze the differences in activation pattern between the two task types in normal controls. In experiment 2 we will analyze activation patterns using the same pair of activation tasks in hemineglect patients, first in the acute phase of their illness and then 6 months later when the hemineglect has improved. We anticipate that SPECT patterns in the acute phase will reflect the patient's dysfunctional clinical state and that the activation pattern will change over time as clinical function returns. In experiment 3 we will probe visual-spatial dysfunction in hemineglect patients experimentally by systematically altering the test conditions. Consequent alterations in task performance will be correlated with changes on SPECT and compared to activation patterns in the patients who were not presented with behavioral interventions and to activation patterns the normal controls. We will attempt to show that experimental manipulations that improve clinical performance also systematically alter rCBF patterns, reflecting plasticity in the visual-spatial system. By combining experimental behavioral methods with newer imaging and data analysis techniques, we have the opportunity to add functional imaging data to models of brain function based to date on clinical observations of brain-injured patients and psychophysical data in normal subjects. Although we have chosen hemineglect as a model to study brain injury, the knowledge gained and techniques-advanced may alter the way we think about the brain's reaction to injury.