Reorganization of Visual Functions After Early Deafness

描述(由申请人提供)：认知技能及其潜在的大脑组织不是固定的，而是可以由个人的经验塑造的。这种依赖经验的可塑性程度为神经系统的重组和适应能力提供了有价值的信息。为此，我们一直在研究先天失聪的人。我们的研究目的是证明耳聋和美国手语(美国手语，聋人使用的视觉手册语言)对视觉及其神经组织的影响。我们的工作假设是，耳聋会改变视觉空间注意力。在我们之前的行为和脑成像工作的基础上，我们将测试耳聋导致外围视觉注意力增强的假设，并将表征这种外围增强对中央呈现的视觉信息处理的影响。注意力是一个多方面的概念，我们将感兴趣的是，除了空间分布之外，视觉注意力的哪些方面可能会被早期耳聋所改变。可能跨模式的可塑性主要是通过重塑通常支持多模式整合的大脑系统来进行的。根据这一观点，我们预计，除了空间注意外，注意的其他方面几乎没有变化，而空间注意是建立了良好的跨模式联系的。相反，另一种观点预测，补偿性可塑性增强了剩余模式的许多方面，聋人可能会在广泛的视觉和注意力技能上表现出增强。首先比较聋人和听力正常的成年人；然后将儿童(7-17岁)包括在内，以表征改变的经验对正在研究的技能的发展轨迹的影响。这些研究将首先对聋人手语者和听力不健全者进行对比，以确定人群差异。然后，聋人、非手语者和听力手语者将接受测试，以分别评估耳聋和ASL使用在观察到的变化中的作用。这一点很重要，因为耳聋和ASL的使用已经被证明对视觉技能有不同的影响。这项工作将使我们能够记录视觉系统表现出的可塑性行为的范围，以及这种可塑性的边界条件。此外，它还将为开发更适合聋人需求的环境提供见解。

DESCRIPTION (provided by applicant): Cognitive skills and their underlying brain organization are not fixed but can be shaped by the experience of the individual. The extent of such experience-dependent plasticity provides valuable information about the ability of the nervous system to reorganize and adapt. To this aim, we have been studying individuals who are born deaf. The goal of our research is to document the effect of deafness and that of American Sign Language (ASL-the visuo-manual language used by the deaf) on vision and its neural organization. Our working hypothesis is that deafness alters visuo-spatial attention. Building on our previous behavioral and brain imaging work, we will test the hypothesis that deafness leads to enhanced peripheral visual attention, and we will characterize the consequences of this peripheral enhancement for the processing of centrally presented visual information. Attention is a multi-faceted concept and we will be interested in asking which other aspects of visual attention, beyond its spatial distribution, may be modified by early deafness. It may be that cross-modal plasticity proceeds primarily by reshaping the brain systems that typically support multimodal integration. Under this view, we expect little to no changes in other aspects of attention beyond spatial attention for which cross-modal links are well established. In contrast, the alternate view predicts that compensatory plasticity enhances many aspects of the remaining modalities, with deaf individuals possibly displaying enhancement on a wide range of visual and attentional skills. Deaf and hearing adults will be compared first; then, children (7-17 years old) will be included so as to characterize the effects of altered experience on the developmental trajectory of the skill under study. These studies will first contrast deaf signers and hearing non-signers to establish a population difference. Deaf non-signers and hearing signers will then be tested to separately assess the contributions of deafness and ASL use in the changes observed. This is important as deafness and ASL use have been documented to have different effects on visual skills. This work will allow us to document the range of plastic behaviors exhibited by the visual system as well as boundary conditions on this plasticity. In addition, it will provide insights for the development of environments better suited to deaf individuals' needs.