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，但可以通过个人的经验来塑造。这种依赖经验的可塑性的程度提供了有关神经系统重组和适应能力的有价值的信息。为此，我们一直在研究天生失聪的人。本研究的目的是记录耳聋和美国手语（ASL-聋人使用的视觉-手动语言）对视觉及其神经组织的影响。我们的工作假设是耳聋改变了视觉空间注意力。基于我们以前的行为和脑成像工作，我们将测试这一假设，即耳聋导致增强周边视觉注意力，我们将描述这种周边增强的后果，为中央呈现的视觉信息的处理。注意力是一个多方面的概念，我们将有兴趣问的其他方面的视觉注意力，超越其空间分布，可能会修改早期耳聋。跨模态可塑性可能主要通过重塑通常支持多模态整合的大脑系统来进行。在这种观点下，我们预计除了空间注意力之外，注意力的其他方面几乎没有变化，而空间注意力的跨通道联系已经建立。相反，另一种观点预测，补偿性可塑性增强了许多方面的其余方式，聋人可能会显示增强广泛的视觉和注意力技能。首先将对聋人和听力正常的成年人进行比较;然后将纳入儿童（7-17岁），以描述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聋人手语者和听力非手语者，以建立人口差异。然后将对聋人非签名者和听力签名者进行测试，以分别评估耳聋和ASL使用对观察到的变化的贡献。这一点很重要，因为耳聋和ASL的使用已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所表现出的塑性行为的范围以及这种塑性的边界条件。此外，它还将为发展更适合聋人需要的环境提供见解。

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.