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，而是可以通过个人的经历来塑造的。这种经验依赖的可塑性的程度提供了有关神经系统重组和适应能力的宝贵信息。为此，我们一直在研究天生失聪的人。我们的研究目的是记录耳聋和美国手语（asl -聋人使用的视觉手册语言）对视觉及其神经组织的影响。我们的假设是耳聋改变了视觉空间注意力。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，我们将描述这种外围视觉注意力增强对集中呈现的视觉信息处理的影响。注意是一个多方面的概念，我们将有兴趣询问视觉注意的哪些其他方面，除了它的空间分布，可能会被早期耳聋所改变。跨模态可塑性可能主要是通过重塑通常支持多模态整合的大脑系统来实现的。根据这一观点，我们预计除了空间注意力之外，其他方面的注意力几乎没有变化，因为跨模态联系已经建立。相反，另一种观点预测，代偿性可塑性增强了其余模式的许多方面，聋人可能在广泛的视觉和注意力技能上表现出增强。聋人和听力正常的成年人将首先进行比较；然后，将包括儿童（7-17岁），以表征改变的经验对所研究技能发展轨迹的影响。这些研究将首先对比失聪的手语者和听力正常的非手语者，以确定人口差异。然后，聋人非手语者和听力健全的手语者将分别接受测试，以评估耳聋和使用美国手语对观察到的变化的贡献。这一点很重要，因为耳聋和使用美国手语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所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.