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切除大脑半球 治疗某些疑难病症（例如癫痫）的服务。尽管这个程序具有极端的性质， 随着时间的推移，大脑半球切除术引起的视力缺陷可以得到显着的改善，尤其是 当手术在很小的时候进行。这种恢复的基础在于完整的能力 半球“接管”通常由其对应部分执行的功能，从而显着地展示了神经功能 可塑性。令人惊讶的是，很少有人针对支持这一机制的系统性探索。 可塑性。我们项目的目标是描述完整半球视觉处理的重新映射 通过行为和神经影像（fMRI）研究来了解这些独特的个体。首先，在层面上 在早期视觉皮层中，我们的目标是表征视网膜专题图的（重新）组织。一个有趣的 激发这项研究的假设涉及完整枕叶发展敏感性的能力 随着时间的推移，受影响的同侧半视野。其次，在更高层次的视觉皮层层面，我们的目标是 表征识别突出物体类别（例如面部）所涉及的皮质地形 和视觉词形式。单个半球处理多个此类类别的能力表明 高级物体识别架构的重要调整。例如，更紧凑的 不同类别下视觉表征的整合可以促进成功的识别 我们的目标是阐明这种功能整合的神经基础。第三， 我们建议将复苏的程度和概况描述为许多关键变量的函数 与程序的具体情况有关。特别是执行手术的一侧（即 右或左半球切除术）可以确定不同组的不同恢复/发展 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/偏侧化（例如，右腹侧皮层中的面孔和左侧的视觉单词形式）。总而言之，由 由于我们接触到了这一稀有人群，我们的调查提供了前所未有的机会来探索 皮质重新映射的一个激进案例以及这种重新映射对视觉感知的影响。学位 以及在神经元可用性急剧下降的情况下恢复视觉功能的方式 资源可以揭示神经可塑性的边界条件。至关重要的是，差分重映射 不同视觉能力的改善说明了恢复和恢复的关键神经机制 可塑性。