REORGANIZATION OF VISUAL FUNCTIONS AFTER EARLY DEAFNESS

描述（改编自申请人摘要）：本研究的目标是 评估和区分耳聋和获得体征的影响 视觉系统的组织语言。听觉中的视觉能力 将个体与聋人签名者进行比较。单独记录 从手语看耳聋的作用，聋人与手语接触最少 也将包括作为本地签名者的听力个人。的确， 现有的文献表明，耳聋和美国人的习得， 手语有不同的和单独的影响重组的 视觉功能视觉系统被修改的方面将 首先通过比较视觉过程的行为指数来确定， 这四个民族。大脑组织的改变伴随着 这些行为差异将被表征为功能性差异， 磁共振成像（fMRI）。 现有的文献表明，先天性听觉剥夺是 与行为表现和神经功能的特定增强相关 对周围的运动刺激和视觉刺激作出反应的活动。 由于这种类型的信息主要沿背侧沿着表示， 视觉通路，已经提出，早期耳聋主要影响 背侧视觉通路这项工作将测试的假设，背 通过研究和比较早期耳聋患者的视功能改变， 运动处理和空间定位在聋人和听力。的 耳聋和手语的贡献将通过观察 聋哑人，手语经验和听力都很低，他们是本地手语者。的 这项工作的第二个目标是测试塑料变化是否确实是特定的 如文献中所假设的，或者如果是塑料的， 变化可能是由早期的价格或签署在其他主要视觉 路径，即腹侧路径。为此，面部处理和 手形处理将在聋人和听力中进行比较， 他们的签名能力。 这些实验将提供新的信息， 视力的改变主要是由于早期听觉剥夺和/或早期获得 的迹象，并将有助于描述这些变化是如何实施的， 皮层水平。由于这些研究将决定视觉方面的 当环境改变时， 在早期，这些结果也将对培训类型产生影响， 这将优化儿童的视觉和注意力技能。

DESCRIPTION (Adapted from Applicant's abstract): The goal of this research is to assess and separate the effect of deafness and of acquisition of a sign language on the organization of the visual system. Visual abilities in hearing individuals will be compared with those of deaf signers. To separately document the role of deafness from that of signing, deaf with minimal exposure to sign and hearing individuals who are native signers will also be included. Indeed, the existing literature indicates that deafness and acquisition of American Sign Language have different and separate effects on the reorganization of visual functions. The aspects of the visual system that have been modified will be first determined by comparing behavioral indices of visual processes in these four populations. Modifications in brain organization that accompany these behavioral differences will be then characterized with functional magnetic resonance imaging (fMRI). The existing literature indicates that congenital auditory deprivation is associated with specific enhancement of behavioral performance and neural activity in response to moving stimuli and visual stimuli in the periphery. Since this type of information is predominantly represented along the dorsal visual pathway, it has been proposed that early deafness affects predominantly the dorsal visual pathway. This work will test the hypothesis that dorsal visual functions are altered after early deafness, by studying and comparing motion processing and spatial localization in deaf and hearing. The contribution of deafness and signing will be separately assessed by looking at deaf with minimal signing experience and hearing who are native signers. The second goal of this work is to test whether plastic changes are indeed specific to the dorsal pathway as has been hypothesized in the literature or if plastic changes can be induced by early dearness or signing in the other main visual pathway, i.e. the ventral pathway. For that purpose, face processing and handshape processing will be compared in deaf and hearing as a function of their signing ability. These experiments will provide new information about which sub-systems within vision are most altered by early auditory deprivation and/or early acquisition of signs, and will help to characterize how these changes are implemented at the cortical level. Since these studies will determine the aspects of visual perception that are most likely to reorganize when the environment is altered early on, these results will also carry implications for the kind of training that would optimize visual and attentional skills in children.