Braille Reading & Adaptive Plasticity in the Human Brain

该提案旨在了解支持行为适应的功能架构， 失明很可能视觉皮层起着主要作用，因为它的活动在盲人中增加， 各种非视觉感知和认知任务。此外，盲人枕叶皮层的破坏 损害盲文阅读，表明在这一关键技能中可能起作用。盲人也表现出上级知觉 处理非视觉刺激。基于这些发现，我们将探讨三个假设：（1）重组 视觉皮层尊重视力正常的人的层次处理和领域专门化原则 这与视网膜视区和中央凹周边偏心轴有关。(2)重组 视觉皮层对盲人的知觉和认知行为有重要作用。(3)增强的性能 在盲人的各种任务中注意到， 视觉皮层外的动力学先天性/早期盲、意外性 盲人和正常视力的人将被用来评估这些假设。两项研究的结果将 以揭示早期视觉区域和/或中央凹表示的区域 选择性地处理较低级别的任务，如亚词汇处理或刺激幅度检测，以及是否 更高视觉枕颞区和/或颞叶旁/周边偏心表征选择性 处理更复杂的任务，如语义分类或感官工作记忆。的结果 另外两项研究将进行分析，以揭示枕部重叠或子部分的程度， 颞区和/或颞旁/外周偏心表示处理更高级别的识别 对非语言和语言的记忆。重组的视皮层中的亚模态分离将是 通过涉及触觉振动或听觉音调刺激的研究进行评估。 在所有实验中，视觉区和选择性非视觉区的血氧水平依赖性反应动力学 将进行定量分析，并与性能相关，以确定可能的因果关系。

This proposal is designed to understand the functional architecture supporting behavioral adaptations to blindness. It is likely that visual cortex plays a major role because its activity increases in blind people during various non-visual perceptual and cognitive tasks. In addition, disruption of occipital cortex in blind people impairs Braille reading, indicating a likely role in this critical skill. Blind people also exhibit superior perceptual processing of non-visual stimuli. Based on these findings, we will explore three hypotheses: (1) Reorganized visual cortex respects principles of hierarchical processing and domain specialization found in sighted people that are related both to retinotopic visual areas and to the fovea-periphery eccentricity axis. (2) Reorganized visual cortex contributes to perceptual and cognitive behaviors in blind people. (3) Enhanced performance noted in blind people on a variety of tasks correlates with and perhaps is causally related to altered response dynamics outside visual cortex. An integrated set of fMRI studies in congenitally/early blind, adventitously blind, and normally sighted people will be used to assess these hypotheses. The results from two studies will be analyzed to reveal the degree to which early visual areas and/or regions of foveal representation selectively process lower level tasks like sublexical processing or stimulus amplitude detection, and whether higher visual occipito-temporal areas and/or parafoveal/peripheral eccentricity representations selectively process more complex tasks like semantic categorization or sensory working memory. The results from another two studies will be analyzed to reveal the degree to which overlapping or subparts of occipito- temporal areas and/or parafoveal/peripheral eccentricity representations process higher level recognition memory for non-verbal and verbal items. Submodality separation in reorganized visual cortex will be assessed from studies involving stimulation with tactile vibrations or auditory tones in separate experiments. In all experiments blood oxygen level dependent response dynamics in visual and selective non-visual areas will be quantitatively analyzed and correlated with performance to determine likely causal relationships.