Brain dynamics of lexical retrieval after left hemisphere stroke

左半球卒中后支持词汇提取的脑动力学 这项建议研究了支持慢性中风患者词汇提取的脑动力学。 因左半球病变而导致的失语症。因黄体生成素而出现卒中失语的患者 损伤通常会遇到很大的词汇提取困难。然而，词汇提取能力并不等同 在这些患者身上受到了损害。这种差异的一种可能解释是词汇提取需要 多个认知成分，由不同的神经区域所支配。特别是，患有 左侧前额叶皮质(LPFC)的病变通常可以立即识别它们试图使用的单词 当被要求在几个选项或目标单词的开头之间进行选择时，就说。左侧病变的患者 后颞叶皮质(PLTC)可能难以识别正确的单词，即使它被提供给他们。 因此，LPFC和pLTC在词汇提取、词汇激活和词汇加工的子过程中可能扮演不同的角色 选择和脑网络重组可能因此在LPFC和pLTC卒中后有所不同- 诱导性损伤。一般的认知控制过程被认为在恢复过程中起作用 中风引起的失语症。然而，领域一般认知控制机制的程度 在黄体生成素中风后进行词汇提取的情况尚不清楚。这个项目试图阐明这些问题。在……里面 具体地说，该研究将考察支持词汇提取的时空动力学 黄体生成素卒中后病变覆盖LPFC和PLTC的时间，以及一般领域的认知情况 控制可能处于激活状态。我们的主要假设是，有LPFC周围病变的患者 但pLTC不会显示出更有效地参与领域一般认知控制 在词汇提取机制方面，患者比病变围绕pLTC的患者更多。一种组合 将使用新的理论和方法方法以及既定的任务来评估 词汇提取和领域一般认知控制。目标1将调查LPFC受损的影响 对比pLTC在词汇提取上的差异来推断这些区域在词汇激活和选择中的因果作用 建立了新颖的行为模型。目标2将决定是否以及何时进行领域一般认知 对照PFC区参与LPFC或pLTC损害患者的词汇提取 使用空间增强头皮脑电(EEG)的匹配对照。最后，《目标3》将考察 如果这些组之间的词汇提取能力的差异被大脑的差异所取代 使用脑电衍生的功能连通性测量的连通性。由此造成的个人和社会成本 中风后的词汇提取障碍是相当严重的。这些研究的结果将提供一个关键步骤 了解脑动力学对卒中失语患者词汇提取的支持。这些结果可能 进而引出用于评估词汇提取能力的临床工具。

Brain dynamics supporting lexical retrieval after left hemisphere stroke This proposal examines the brain dynamics supporting lexical retrieval in patients with chronic stroke-induced aphasia due to left-hemisphere (LH) lesions. Patients presenting with stroke-induced aphasia due to LH damage often experience major lexical retrieval difficulties. Lexical retrieval abilities are, however, not equally compromised in these patients. One possible explanation for this variability is that lexical retrieval requires multiple cognitive components that are subserved by different neural regions. In particular, patients with lesions to the left lateral prefrontal cortex (LPFC) can often immediately recognize the word they are trying to say when given a choice between a few options or the onset of the target word. Patients with lesions in the left posterior temporal cortex (pLTC) may have trouble recognizing the correct word even when it is given to them. The LPFC and pLTC may therefore play different roles in subprocesses of lexical retrieval, lexical activation and selection, and brain network reorganization may consequently be different after LPFC versus pLTC stroke- induced lesions. Domain-general cognitive control processes have been proposed to play a role in recovery from stroke-induced aphasia. However, the degree to which domain-general cognitive control mechanisms are engaged in lexical retrieval following LH stroke is unclear. This project seeks to shed light on these issues. In particular, the proposed research will examine the spatio-temporal dynamics supporting lexical retrieval following LH stroke when lesions encompass the LPFC versus the pLTC, and how domain-general cognitive control may be engaged. Our main hypothesis is that patients with lesions encompassing the LPFC but not the pLTC will show more efficient engagement of domain-general cognitive control mechanisms in lexical retrieval than patients with lesions encompassing the pLTC. A combination of novel theoretical and methodological approaches will be used along with well-established tasks that assess lexical retrieval and domain-general cognitive control. Aim 1 will investigate the impact of damage to the LPFC versus pLTC on lexical retrieval to infer the causal roles of these regions in lexical activation and selection using established and novel behavioral modeling. Aim 2 will determine if and when domain-general cognitive control PFC regions are involved in lexical retrieval in patients with LPFC or pLTC lesions in comparison with matched-controls using spatially-enhanced scalp electroencephalography (EEG). Finally, Aim 3 will examine if differences in lexical retrieval abilities between these groups are subserved by differences in brain connectivity using EEG-derived functional connectivity measures. The personal and societal cost caused by lexical retrieval disruption after stroke is considerable. The results of these studies will provide a key step toward understanding brain dynamics supporting lexical retrieval in stroke-induced aphasia. These results may in turn lead to clinical tools for the assessment of lexical retrieval abilities.