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， 长期残疾。在最初的康复期之后，中风的恢复依赖于大脑网络的可塑性 免受直接中风的伤害。因此，为了改善失语症的行为和生物治疗，我们必须 了解备用大脑结构和连接如何有助于恢复。经过世纪的研究 已经证明了左半球中风周围的区域和右半球对称的区域， 正常左半球语言网络参与失语症的恢复。然而， 这些区域被招募以及它们在语言恢复中的作用仍不清楚，特别是对于“右翼”来说 半球语言网络。”我们建议检查备用脑结构和连接在 左半球中风幸存者和对照组核心语言功能的恢复。 创新的方法解决了先前研究的主要局限性，通过考虑个体差异， 中风的严重程度，使用任务无关的大脑结构和连接措施，并检查几个核心 语言功能定义的统计分析广泛的行为评估电池。 使用这种新方法进行的初步研究表明， 这些变化改善了语言功能。基于这些发现，我们假设 左半球中风后右半球语言网络的恢复弥补了 语言缺陷我们将使用先进的大脑测试这个假设对多个替代假设， 成像方法来测试整个大脑备用部分的影响。分析将研究如何避免 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。 中风严重程度我们还将测试中风后大脑可塑性的迹象，并测试 中风的位置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接数据，提供更完整的 语言功能的恢复比以前可能。这项研究将大大 推进我们对失语症恢复的生物学基础的理解，这对于设计至关重要 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.