Sensory Cortical Organization and Cross-Modal Plasticity in Blind Humans

盲人的感觉皮层组织和跨模式可塑性

• 批准号: 8691821
• 负责人: JOSEF P RAUSCHECKER
• 金额: $ 38.1万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8691821
• 关键词: 2 year old; Address; Animals; Area; Auditory; Auditory area; Biological Preservation; Birth; Blindness; Brain; Brain Injuries; Brain region; Cerebral cortex; Code; Cognitive; Complex; Development; Devices; Diffusion Magnetic Resonance Imaging; Dorsal; Environmental Risk Factor; Face; Fiber; Functional Imaging; Functional Magnetic Resonance Imaging; Funding; Genetic; Grant; Hearing; Housing; Human; Image Analysis; Individual; Lateral; Lead; Magnetic Resonance Imaging; Measures; Methods; Modality; Occipital lobe; Ocular Prosthesis; Parietal; Parietal Lobe; Pathway interactions; Patients; Pattern; Performance; Physiological; Process; Property; Recruitment Activity; Rehabilitation therapy; Relative (related person); Role; Self-Help Devices; Sensory; Sensory Deprivation; Series; Shapes; Signal Transduction; Source; Specificity; Stimulus; Stream; Tactile; Temporal Lobe; Testing; Time; Touch sensation; Vision; Visual; Visual Cortex; Visually Impaired Persons; Visuospatial; Work; base; blind; experience; extrastriate visual cortex; fascinate; frontal lobe; fusiform face area; information processing; multisensory; neuropsychological; public health relevance; rehabilitation strategy; research study; response; sensory cortex; sensory system; sight for the blind; somatosensory; sound; visual deprivation; volunteer; white matter

DESCRIPTION (provided by applicant): Visual deprivation and blindness famously cause certain brain regions to reorganize in response to environmental constraints and in order to compensate for the loss of a sensory modality. Studies in visually deprived animals and blind humans have long demonstrated the cross-modal recruitment of the visual cortex to process nonvisual information. Yet, little is known about the functional specialization of the reorganized visual cortex (VC), its precise role in the processing of nonvisual information, or the source and routing of its nonvisual inputs. The main aims of the present project are, therefore, to (1) determine the functional organization of the occipital cortex in blind volunteers using a sensory substitution device, (2) to examine whether nonvisual information is processed hierarchically in the VC of the blind, and (3) identify the structural basis of adaptive changes and the source of nonvisual input to VC in the blind. Results from three years of funding by this grant have demonstrated that spatial and nonspatial processing streams do indeed exist for auditory and tactile processing (Renier et al., 2009). Furthermore, spatial auditory and tactile processing in the VC of the early blind occur in the same dorsal-stream regions as visual spatial processing in sighted subjects (Renier et al., 2010). These findings have led us to hypothesize that functionally specialized modules are preserved in the cortex of the early blind. We will pursue this hypothesis further by testing paradigms within the ventral stream. Thus, using functional magnetic resonance imaging, we will examine brain activity in blind subjects while they identify (via the auditory modality) houses, faces and 2-D geometrical shapes coded into sound patterns. These experiments will allow us to determine whether the parahippocampal place area (PPA), the fusiform face area (FFA), and the lateral occipital complex (LOC) retain their designated functional roles in early blindness, while switching their input modality. We will also examine the organization of VC by testing whether nonvisual information is processed in a hierarchical manner, in the same way that normal sensory information is processed in its intact sensory system. Using complexity-varied pitch information, we will determine if early-to-late visual regions of the blind respond to sound in the direction of simple-to-complex levels of pitch processing. Finally, using diffusion tensor imaging (DTI) and analysis of functional connectivity, we will investigate the structural basis of adaptive changes in the cerebral cortex and white matter of blind subjects. Using DTI, we will examine the strength of white-matter fiber tracts projecting to and from VC in both subject groups, thus determining relative changes in the connections between VC and other cortical areas. We will also test how visual and other sensory areas interact during auditory and tactile information processing in blind and sighted volunteers, and whether this interaction depends on the strength of anatomical pathways connecting these areas. Combining the two different methodological approaches will provide us an excellent opportunity to identify the source of nonvisual inputs to VC in the early blind.

描述（由申请人提供）：众所周知，视觉剥夺和失明会导致某些大脑区域根据环境限制进行重组，并补偿感觉方式的损失。对视力丧失的动物和盲人的研究早已证明视觉皮层可以跨模式募集来处理非视觉信息。然而，人们对重组视觉皮层（VC）的功能特化、其在非视觉信息处理中的精确作用或其非视觉输入的来源和路由知之甚少。因此，本项目的主要目标是（1）使用感觉替代装置确定盲人志愿者枕叶皮层的功能组织，（2）检查非视觉信息是否在盲人的 VC 中进行分层处理， (3) 识别自适应变化的结构基础和盲人视觉视觉输入的来源。这项拨款三年的资助结果表明，听觉和触觉处理确实存在空间和非空间处理流（Renier 等，2009）。此外，早期盲人 VC 中的空间听觉和触觉处理与视力正常受试者的视觉空间处理发生在相同的背流区域（Renier 等，2010）。这些发现使我们推测早期盲人的皮层中保留了功能专门的模块。我们将通过测试腹侧流内的范例来进一步探讨这一假设。因此，利用功能性磁共振成像，我们将检查盲人受试者识别（通过听觉方式）房屋、面孔和编码成声音模式的二维几何形状时的大脑活动。这些实验将使我们能够确定海马旁区域（PPA）、梭形面部区域（FFA）和枕外侧复合体（LOC）是否在早期失明中保留其指定的功能角色，同时切换其输入模式。我们还将通过测试非视觉信息是否以分层方式处理来检查 VC 的组织，就像在完整的感觉系统中处理正常的感觉信息一样。使用复杂程度不同的音调信息，我们将确定盲人的早期到晚期视觉区域是否以简单到复杂的音调处理级别对声音做出反应。最后，利用弥散张量成像（DTI）和功能连接分析，我们将研究盲人受试者大脑皮层和白质适应性变化的结构基础。使用 DTI，我们将检查两个受试者组中投射到 VC 和从 VC 投射的白质纤维束的强度，从而确定 VC 和其他皮质区域之间连接的相对变化。我们还将测试盲人和视力正常的志愿者在听觉和触觉信息处理过程中视觉和其他感觉区域如何相互作用，以及这种相互作用是否取决于连接这些区域的解剖通路的强度。结合两种不同的方法将为我们提供一个绝佳的机会来识别早期盲人风险投资的非视觉输入来源。