Braille Reading & Adaptive Plasticity in the Human Brain

描述(由申请人提供)：本提案旨在理解支持失明行为适应的功能架构。视觉皮质可能起主要作用，因为盲人在各种非视觉感知和认知任务中，它的活动增加。此外，盲人枕叶皮质的破坏会损害盲文阅读，这表明这一关键技能可能起到了作用。盲人对非视觉刺激也表现出卓越的知觉处理能力。基于这些发现，我们将探索三个假说：(1)重组的视皮层尊重在视力正常的人身上发现的与视网膜视觉区域和中心凹-周边偏心轴相关的分层加工和领域专门化原则。(2)重组的视皮层有助于盲人的知觉和认知行为。(3)盲人在各种任务中的表现增强与视觉皮质外的反应动力学改变相关，甚至可能是因果关系。在先天/早期失明、意外失明和正常视力的人群中，一组完整的功能磁共振研究将被用来评估这些假说。这两项研究的结果将被分析，以揭示早期视觉区域和/或中心凹表征区域选择性地处理较低水平的任务，如亚词汇加工或刺激幅度检测，以及较高视觉枕颞区和/或旁中央凹/外周偏心表征是否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被分析，以揭示枕颞区和/或侧凹/外周偏心表征的重叠或子部分对非言语和言语项目的高水平再认记忆的处理程度。在单独的实验中，将通过涉及触觉振动或听觉音调刺激的研究来评估重组视觉皮质中的亚模式分离。在所有实验中，视觉和选择性非视觉区域的血氧水平依赖反应动力学将被定量分析，并与表现相关联，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.