Neglect and Neural Mechanisms of Magnitude Estimation

本研究的目的是为当代空间忽视理论添加定量元素，并将不同的理论结合成一个模型。理论的发展可以改善治疗。每年都有大量的中风患者受到忽视，目前的治疗效果有限。当代忽视理论从空间的心理表征、空间注意力和空间定向运动的角度来看待这种障碍。他们不能解决最近一些与量级估计有关的经验性观察——对大小、响度、重量等的误解。我们提出，除了空间的心理表征外，刺激强度的心理表征是由大脑中的神经系统构建的，并且两种类型的表征都在忽视中被改变。此外，我们提出刺激强度的表征是根据比率尺度的心理物理原理发展起来的，这是估计强度的基础。刺激强度的表征增加了当代忽视理论中缺失的定量元素。我们期待这一新概念将极大地推动有关忽视的理论，并引领新的研究方向。它也直接适用于治疗，例如，通过比例缩放的直接训练恢复刺激强度的表征。提出了六个实验。研究对象为左右脑半球病变患者。缺血性中风后，选择(1)忽视的临床症状和(2)与忽视相关的特定神经系统损伤。非患者对照受试者将根据年龄、性别和种族进行匹配。实验一验证了忽视患者对刺激强度的表征在多种感觉模式中发生改变的假设。实验二验证了注意将空间表征和刺激强度结合在一起的假设。实验三验证了刺激强度表征在每个大脑半球构建的假设。实验IV-VI检验了忽视患者比例比例改变的其他解释。最后，我们建议在此建议的过程中开发和测试比例缩放的数学模型。

The goal of this research is to add a quantitative element to contemporary theories of spatial neglect and to combine disparate theories into one model. Theoretical development can lead to improved treatment. Neglect affects a large number of stroke patients each year, and current treatments are of limited benefit. Contemporary theories of neglect view the disorder in terms of mental representations of space, spatial attention, and spatially- directed movements. They cannot address a number of recent empiric observations related to magnitude estimation -- misperceiving size, loudness, weight, and the like. We propose that mental representations of stimulus intensity are constructed by neural systems in the brain, in addition to mental representations of space, and that both types of representations are altered in neglect. Further, we propose that representations of stimulus intensity are developed in accordance with the psychophysical principle of ratio scaling, which is the basis for magnitude estimation. Representations of stimulus intensity add the quantitative element that is missing in contemporary theories of neglect. We anticipate this new concept will significantly advance theories concerning neglect and lead to new directions in research. It is also directly applicable to treatment, e.g., rehabilitating representations of stimulus intensity through direct training in ratio scaling. Six experiments are proposed. Subjects will be patients with right and left hemisphere lesions . following ischemic stroke who are selected for (1) clinical signs of neglect and (2) damage to a specific, neural system associated with neglect. Non-patient control subjects will be matched for age, gender, and race. Experiment I tests the hypothesis that representations of stimulus intensity are altered in multiple sensory modalities among patients with neglect. Experiment II tests the hypothesis that attention binds representations of space and stimulus intensity together. Experiment III tests the hypothesis that representation of stimulus intensity are constructed in each cerebral hemisphere. Experiments IV-VI examine alternative explanations for altered ratio scaling among patients with neglect. Finally, we propose to develop and test a mathematical model of ratio scaling during the course of this proposal.