Neural Plasticity and Recovery of Visual Functions in Patients with Hemispherecto

大脑半球缺失患者的神经可塑性和视觉功能恢复

• 批准号: 8584185
• 负责人: Marlene Behrmann
• 金额: $ 18.61万
• 依托单位: CARNEGIE-MELLON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8584185
• 关键词: Address; Adopted; Affect; Age; Arbitration; Architecture; Bees; Behavior; Behavioral; Brain; Categories; Cerebral hemisphere; Cognitive; Coupled; Development; Epilepsy; Excision; Exhibits; Face; Fiber; Functional Hemispherectomy; Functional Magnetic Resonance Imaging; Goals; Hemispherectomy; Human; Individual; Investigation; Ipsilateral; Left; Light; Maps; Mediating; Medical; Methods; Modeling; Nature; Neurobiology; Neuronal Plasticity; Occipital lobe; Operative Surgical Procedures; Patients; Pattern; Population; Procedures; Process; Property; Pulvinar structure; Recovery; Rehabilitation therapy; Research; Residual state; Resources; Right-On; Role; Services; Side; Structure; Study models; Sum; Taxes; Time; Vision; Visual; Visual Cortex; Visual Fields; Visual Perception; Visual system structure; Work; base; cognitive function; coping; design; innovation; insight; neuroimaging; neuromechanism; neuropsychological; novel; object recognition; patient population; pressure; psychologic; public health relevance; relating to nervous system; retinotopic; superior colliculus Corpora quadrigemina; tool; visual process; visual processing

Summary A hemispherectomy involves the surgical disconnection or removal of a cerebral hemisphere in the service of treating certain intractable conditions (e.g. epilepsy). Despite the extreme nature of this procedure, the visual deficits introduced by hemispherectomy can undergo impressive improvement over time, especially when the procedure is conducted at an early age. The basis of this recovery lies in the ability of the intact hemisphere to 'take over' the functions normally performed by its counterpart in a remarkable display of neural plasticity. Surprisingly, rather little systematic exploration has been directed at the mechanisms supporting this plasticity. The goal of our project is to characterize the remapping of visual processing in the intact hemisphere of these unique individuals by means of behavioral and neuroimaging (fMRI) investigations. First, at the level of the early visual cortex, we aim to characterize the (re)organization of retinotopic maps. One intriguing hypothesis that motivates this investigation concerns the ability of the intact occipital lobe to develop sensitivity over time to the affected ipsilateral hemifield. Second, at the level of higher-level visual cortex, we aim to characterize the cortical topography involved in the recognition of prominent object categories such as faces and visual word forms. The ability of a single hemisphere to cope with multiple such categories is indicative of important adjustments in the architecture of high-level object recognition. For instance, a more compact integration of visual representations underlying different categories could mediate successful recognition processes at the neural level and we aim to clarify the neural underpinnings of this functional integration. Third, we propose to characterize the extent and the profile of the recovery as a function of a number of key variables pertaining to the specifics of the procedure. In particular, the side on which the procedure was performed (i.e. right or left hemispherectomy) could determine the differential recovery / development of different sets of abilities. This hypothesis is particularly relevant for certain visual categories commonly displaying hemispheric dominance / lateralization (e.g. faces in the right ventral cortex and visual word forms in the left). In sum, by virtue of our access to this rare population, our investigation provides an unprecedented opportunity to explore a radical case of cortical remapping and the consequences of this remapping for visual perception. The degree and the manner by which visual functions are regained under a drastic reduction in the availability of neural resources can shed light on the boundary conditions of neural plasticity. Critically, the differential remapping and improvement of different visual abilities speak to the key neural mechanisms underlying recovery and plasticity.

概括 半球切除术涉及手术断开或去除脑半球 治疗某些顽固疾病的服务（例如癫痫）。尽管此程序具有极端性质，但 半球切除术引入的视觉缺陷会随着时间的流逝而经历令人印象深刻的改善，尤其是 当该程序在很小的时候进行。这种恢复的基础在于完整的能力 半球以“接管”通常由同行执行的功能在神经的显着显示中 可塑性。令人惊讶的是，几乎没有系统的探索是针对支持此的机制 可塑性。我们项目的目的是表征完整半球视觉处理的重新映射 在这些独特的个体中，通过行为和神经影像学（fMRI）调查。首先，在 早期的视觉皮层，我们旨在表征（重新）的视网膜图。一个有趣的 激励这种调查的假设涉及完整枕叶发展敏感性的能力 随着时间的流逝，受影响的同侧半场。第二，在高级视觉皮层的水平上，我们的目标是 描述识别诸如面孔之类的突出物体类别的皮质地形 和视觉单词形式。单个半球应对多个类别的能力表明 高级对象识别体系结构中的重要调整。例如，一个更紧凑的 视觉表示基础不同类别的集成可以调解成功的识别 神经层面的过程，我们旨在阐明这种功能整合的神经基础。第三， 我们建议表征恢复的程度和轮廓，这是许多关键变量的函数 与该过程的细节有关。特别是，执行过程的一侧（即 右或左半切除术）可以确定不同集合的差异恢复 /开发 能力。该假设与通常显示半球的某些视觉类别特别相关 优势 /侧向化（例如，右侧腹皮层和左侧的视觉单词形式）。总而言之 我们进入这个罕见人群的优点，我们的调查为探索提供了前所未有的机会 皮质重新映射的根本案例以及此重新映射的视觉感知的后果。学位 以及在神经的可用性急剧下恢复视觉功能的方式 资源可以阐明神经可塑性的边界条件。至关重要的是差重映射 改善不同视觉能力的说明是恢复的关键神经机制和 可塑性。