Visual Processing in Deaf Subjects: Effects of Auditory Deprivation and Experience with a Visual Language

该项目调查的知觉后果改变的感官输入早期发展，通过研究聋人的视觉知觉，谁被剥夺了自出生以来，谁已经获得了视觉语言（美国手语，ASL）的沟通。 长期以来，人们一直认为（主要是通过轶事证据）聋人“看”得更好（盲人“听”得更好）;然而，只有少数研究试图系统地描述聋人手语者的视觉能力。为了研究这个问题，聋人和听力受试者将接受各种视觉任务的测试。 特别是，视觉运动处理将被评估有几个原因。第一，运动是视觉处理的一个基本方面，关于它的神经基础已经知道很多。 第二，动物研究的结果表明，运动系统可能特别容易受到感官输入改变的影响。 第三，手的运动是美国手语习得和理解的一个组成部分，因此有理由相信，对此类运动线索的依赖增加可能会增强和/或改变聋人的运动感知。 视觉感知实验将涉及测试运动（和其他视觉）处理能力的各个维度，以阐明聋人视觉处理的哪些特定方面发生了变化。 一旦确定了产生听力和失聪受试者之间最大感知差异的视觉刺激/任务类型，将采用人脑成像技术（如功能性磁共振成像或磁源成像）来定位感知差异背后的神经区域或结构。 此外，脑成像研究可能揭示特定脑区对早期感觉剥夺的敏感性和补偿能力的差异。 这些实验将推进我们的知识，在多大程度上发展的感觉区域的大脑可以重组自己，以响应改变的感觉输入，与视觉发展的原则一般的影响。 此外，这些实验应该揭示神经反应性和连接性受到感官环境输入影响的处理水平。 这些结果也可能是有用的，在设计补偿程序的感觉剥夺的人，谁可以训练利用这些方面的感觉处理是最适应改变早期的感觉输入。

This project investigates the perceptual consequences of altered sensory input early in development, by studying visual perception in deaf adults who have been auditorily deprived since birth and who have acquired a visual language (American Sign Language, ASL) for communication. It has long been thought (mostly through anecdotal evidence) that the deaf `see` better (and that the blind `hear` better); however, only a handful of studies have attempted to characterize systematically the visual capacity of deaf signers. To investigate this issue, deaf and hearing subjects will be tested on a variety of visual tasks. In particular, visual motion processing will be assessed for several reasons. One, motion is a fundamental aspect of visual processing and much is known about its neural basis. Two, results from animal studies suggest that the motion system may be especially susceptible to changes following altered sensory input. Three, motion of the hands is an integral part of the acquisition and comprehension of ASL, and thus there is reason to believe that the increased reliance on such motion cues may enhance and/or alter motion perception in the deaf. Visual perceptual experiments will involve testing various dimensions of motion (and other visual) processing capabilities, in order to elucidate which specific aspects of visual processing are altered in the deaf. Once the types of visual stimuli/tasks yielding the greatest perceptual differences between hearing and deaf subjects have been determined, human brain imaging techniques (such as functional Magnetic Resonance Imaging or Magnetic Source Imaging) will be employed to localize neural areas or structures underlying the perceptual differences. In addition, brain imaging studies may reveal differences across specific brain areas in susceptibility to, and ability to compensate for, early sensory deprivation. These experiments will advance our knowledge regarding the degree to which developing sensory areas of the brain can reorganize themselves in response to altered sensory input, with implications for principles of visual development in general. Moreover, the experiments should shed light on the processing levels at which neural responsivity and connectivity are influenced by input from the sensory environment. The results may also be useful in designing compensatory programs for sensory-deprived persons, who could be trained to exploit those aspects of sensory processing that are most adaptive in response to altered early sensory input.