Neglect and Neural Mechanisms of Magnitude Estimation

本研究的目的是为当代空间忽视理论增加一个量化的元素，并将不同的理论联合收割机整合成一个模型。理论的发展可以改善治疗。每年都有大量的脑卒中患者受到神经内分泌素的影响，而目前的治疗效果有限。当代忽视理论认为，空间的心理表征，空间注意，空间定向运动方面的障碍。他们不能解决一些最近的经验观察有关的震级估计-误解的大小，响度，重量，等等。我们认为，刺激强度的心理表征是由大脑中的神经系统构建的，除了空间的心理表征之外，这两种类型的表征在忽视中都会改变。此外，我们建议，表示的刺激强度的发展与心理物理学原则的比例缩放，这是幅度估计的基础。对刺激强度的表征增加了当代忽视理论中所缺失的定量元素。我们预计，这一新概念将大大推进有关忽视的理论，并导致新的研究方向。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。受试者将是患有左右半球病变的患者。缺血性中风后，根据（1）忽视的临床体征和（2）与忽视相关的特定神经系统损伤选择患者。非患者对照受试者的年龄、性别和人种将匹配。实验一测试的假设，刺激强度的表征被改变，在多个感官模式之间的忽视患者。实验二测试的假设，注意绑定的空间和刺激强度的表征在一起。实验三验证了刺激强度表征是在大脑各半球构建的假设。实验IV-VI检查替代解释改变比例缩放忽视患者。最后，我们建议在本提案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.