Contributions of spared brain structures and connections to aphasia recovery

语言障碍，或失语症，是左半球中风后的常见问题，并导致显著 长期残疾。在最初的康复阶段之后，中风的恢复依赖于大脑网络的可塑性 避免了直接的中风伤害。因此，要改进失语症的行为和生物治疗，我们必须 了解备用的大脑结构和连接如何有助于恢复。一个多世纪的研究 证明了中风周围的左半球区域和与之对称的右半球区域 正常左半球语言网络参与失语症的康复。然而，这些机制通过 这些区域是被招募的，它们在语言恢复中的作用仍然不清楚，特别是对于 西半球语言网络。我们建议研究备用的大脑结构和连接在 一大组左半球中风幸存者和配对对照组核心语言功能的恢复。 这些创新的方法解决了先前研究的主要局限性，考虑到了 中风严重程度，使用与任务无关的大脑结构和连接性测量，并检查几个核心 语言功能是通过对广泛的行为评估单元进行统计分析来定义的。 使用这种新方法的初步研究表明，右脑语言网络的某些部分 中风后，这些变化改善了语言结果。基于这些发现，我们假设 左半球中风后右半球语言网络的重新招募补偿了 语言缺陷。我们将使用高级大脑，针对多个备选假设来检验这一假说 成像方法，以测试整个大脑备用部分的影响。分析将检查如何避免 大脑结构和连接有助于语言恢复，解释了语言恢复的个体差异 中风的严重程度。此外，我们还将测试中风后大脑可塑性的迹象，并测试 卒中部位和大脑可塑性的模式，以更好地了解恢复的机制。新的多- 模态分析方法将整合大脑结构和连通性数据，提供更完整的 语言功能恢复的图景比以前任何时候都可能。这项研究将具有重要的意义 促进我们对失语症康复的生物学基础的理解，这对于设计 最有效的治疗方法。

Language impairment, or aphasia, is a common problem after left hemisphere stroke, and causes significant long-term disability. After the initial period of healing, recovery from stroke relies on plasticity in brain networks spared from direct stroke damage. Thus, to improve behavioral and biological treatments for aphasia, we must understand how spared brain structures and connections contribute to recovery. Over a century of research has demonstrated that left hemisphere areas surrounding the stroke and right hemisphere areas symmetric to the normal left hemisphere language network participate in aphasia recovery. However, the mechanisms by which these areas are recruited and their roles in language recovery remain unclear, particularly for the “right hemisphere language network.” We propose to examine the role of spared brain structures and connections in recovery of core language functions in a large group of left hemisphere stroke survivors and matched controls. The innovative methods address major limitations of prior studies by accounting for individual differences in stroke severity, using task-independent brain structure and connectivity measures, and examining several core language functions as defined by statistical analysis of an extensive behavioral assessment battery. Preliminary studies using this new approach suggest that parts of the right hemisphere language network grow after stroke, and that these changes improve language outcomes. Based on these findings, we hypothesize that recruitment of the right hemisphere language network after left hemisphere stroke compensates for language deficits. We will test this hypothesis against multiple alternative hypotheses, using advanced brain imaging methods to test for effects throughout spared parts of the brain. Analyses will examine how spared brain structures and connections contribute to language recovery, accounting for individual differences in stroke severity. We will additionally test for signs of brain plasticity after stroke and test relationships between stroke location and patterns of brain plasticity to better understand the mechanisms of recovery. New multi- modal analysis methods will integrate the brain structure and connectivity data, providing a more complete picture of recovery of language functions than has been possible before. This research will significantly advance our understanding of the biological basis of aphasia recovery, which will be vital in order to design maximally effective treatments.