Dissociating Components of the Attentional Network in Neglect

描述（由申请人提供）：中风后的脑损伤影响许多美国人，对生活质量和进行日常生活活动的能力产生重大影响。为了最大限度地减少中风对人类和经济的影响，需要了解预测恢复和成功康复的因素。视觉忽视是右半球脑损伤的常见后果，这种症状（或综合征）的存在是临床结果不佳的主要预测因素。视觉忽视是一种临床上的注意力缺陷，其中人没有注意到或对病变对面的项目做出反应。因此，一个右半球中风的人可能只吃盘子右边的食物，忽略左边的食物，或者可能只刮脸的右边，等等。Nephalocyte已经被研究了很多年，部分原因是它的重要临床意义，但也因为它有可能提供关于注意力的大脑机制的见解。最常见、最严重和最持久的忽视是在右半球受损后，导致对左半球的忽视。右忽视的存在是更有争议的，临床意义较小。由于这些原因，本研究仅限于研究左忽视由于右半球的损害。关于忽视的两个最基本的问题仍然没有答案，并且在科学文献中存在深刻的争议。简单地说，这些问题是：赤字的性质是什么？导致忽视的大脑损伤的关键区域是什么？我们提出了一个简单的理论框架来回答这些问题，并为注意力的不同观点提供和解。我们认为，视觉忽视是一种复杂的综合征，尽管如此，它还是可以分解成一系列的缺陷，这些缺陷是由皮质的四个区域的损伤或功能障碍引起的。这四个皮层区域代表了大脑注意力网络中的离散但相互关联的模块。顶内沟是一个参与确定项目整体结构并对其做出反应的区域;该区域的损伤与线平分任务的偏差有关。颞盖和颞叶（一个通常被称为上级颞回的区域）参与了对物品的定向;该区域的损伤将导致行取消任务的错误。颞顶交界处参与了对项目的显著性分配;该区域的损伤将导致视觉消退-只有在良好视野中有项目时才能报告受损视野中的项目。最后，前眼区是主要与知觉抑制有关的区域;对该区域的损伤将导致注意力分散的增加。我们认为，核心领域和症状的争议是由于这四个系统受损的患者样本的可变性。本研究通过在正常观察者中融合使用神经心理学、功能性MRI和经颅磁刺激来测试这些预测。

DESCRIPTION (provided by applicant): Brain damage following stroke affects many Americans, having a major impact on quality of life and the ability to carry out activities of daily life. To minimize the human and economic impact of stroke, the factors that predict recovery and successful rehabilitation need to be understood. Visual neglect is a common consequence of brain damage to the right hemisphere, and the presence of this symptom (or syndrome) is a major predictor of poor clinical outcomes. Visual neglect is a clinical deficit of attention, in which the person fails to notice, or to respond to items opposite the lesion. So a person with a stroke to the right hemisphere may eat from only the right hand side of their plate, ignoring the food on the left, or may shave only the right side of their face, and so on. Neglect has been studied for many years, in part for its major clinical significance, but also because it has the potential to provide insight into brain mechanisms of attention. The most common, severe and enduring neglect follows damage to the right hemisphere, leading to neglect of the left. The presence of right neglect is more controversial, and of lesser clinical significance. For these reasons, the present study is confined to studies of left neglect due to right hemisphere damage. The two most fundamental questions about neglect remain unanswered, and the subject of deep controversy in the scientific literature. Simply stated, these are: what is the nature of the deficit? and what are the key areas of brain damage that cause neglect? We propose a simple theoretical framework for answering these questions and providing rapprochement for the divergent views of attention. We propose that visual neglect is a complex syndrome that is nonetheless dissociable into sets of deficits that result from damage to, or dysfunction of, four regions of the cortex. These four cortical regions represent discreet, yet interconnected modules in the attentional network of the brain. The intraparietal sulcus is a region involved in determining the global structure of items, and responding to them; damage to this region is associated with bias on the line bisection task. The temporal operculum and insula (a region often referred to as superior temporal gyrus) is involved in orienting to items; damage to this region will lead to errors on the line cancellation task. The temporoparietal junction is involved in assigning salience to items; damage to this region will lead to visual extinction - a failure to report items in the impaired visual field only if there are items in the good field. Finally the frontal eye fields are regions primarily concerned with perceptual inhibition; damage to this region will lead to increased distractibility. We propose that the controversies over the core areas and symptoms are due to variability in sampling patients with damage to these four systems. The present study tests these predictions by converging use of neuropsychology, functional MRI, and transcranial magnetic stimulation in normal observers.