Braille Reading & Adaptive Plasticity in the Human Brain

描述（由申请人提供）：本提案旨在了解支持失明行为适应的功能架构。视觉皮层可能起着重要作用，因为盲人在各种非视觉感知和认知任务中其活动增加。此外，盲人枕叶皮层的破坏会损害盲文阅读，这表明在这一关键技能中可能起着作用。盲人对非视觉刺激也表现出上级的知觉处理能力。基于这些发现，我们将探讨三个假设：（1）重组的视觉皮层尊重层次加工和领域专业化的原则，发现在正常人都与视网膜视区和中央凹周边偏心轴。(2)重组的视觉皮层有助于盲人的感知和认知行为。(3)盲人在各种任务上的表现增强与视觉皮层外的反应动力学改变相关，也许是因果关系。一套完整的功能磁共振成像研究先天性/早期失明，意外失明，视力正常的人将被用来评估这些假设。两项研究的结果将进行分析，以揭示在何种程度上早期视觉区和/或中央凹代表区域选择性地处理较低级别的任务，如词汇处理或刺激幅度检测，以及是否更高的视觉枕颞区和/或旁/周边偏心率代表选择性地处理更复杂的任务，如语义分类或感觉工作记忆。另外两项研究的结果将进行分析，以揭示枕颞区和/或旁额叶/周边偏心表征的重叠或子部分处理非言语和言语项目的高水平再认记忆的程度。重组的视觉皮层中的亚模态分离将从涉及在单独实验中用触觉振动或听觉音调刺激的研究中进行评估。在所有实验中，将对视觉和选择性非视觉区域中的血氧水平依赖性反应动力学进行定量分析，并将其与表现相关联，以确定可能的因果关系。

DESCRIPTION (provided by applicant): 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.