Temporal-spatial mapping of cortical networks important for human cognition

 描述(申请人提供)：为了避免耐药癫痫手术后的语言障碍，临床医生主要依靠电皮质刺激标测(ESM)，但这可能会引发后放电、临床癫痫发作或引起不适感，所有这些都可能阻止某些区域的标测。此外，ESM可能非常耗时，由此产生的损害通常是“要么全有要么全不”，从而使其解释复杂化。长期以来，这些实用的限制促使被动皮层脑电图术(ECoG)作为一种替代或补充的功能标测技术，可以同时标测所有部位的功能，从而显著节省时间，而不会产生不良副作用。最近的技术发展也允许在测试期间在线执行ECoG功能映射，但这些结果与ESM之间的对应关系对于语言映射并不像对运动映射那样好。这可能部分是因为，即使是简单的语言任务，如物体命名或单词阅读，也需要广泛分布的、可能多余的负责认知加工不同阶段的皮质区域的招募和相互作用，以及因为对任务表现至关重要的激活程度没有先验阈值。我们的总体假设是，皮层部位的功能重要性取决于它在任务相关网络动力学中的作用，即激活在执行成功任务所必需的不同认知操作的分布的皮质区域之间的传播。在本项目中，我们将研究口语产生的任务相关网络动力学，以提高ECoG语言地图的准确性，并更好地理解ECoG语言地图和ESM语言地图之间的关系。首先，我们将使用ECoG来捕捉一系列简单的单词产生任务中网络传播的精细时间动态。我们将把这些网络动力学分解成与负责每个任务的结构性认知操作的功能解剖模块相对应的时间级联子网。此外，我们还将确定作为集线器的高中心性NOE，以促进跨子网传播。其次，我们将通过暂时停用连接子网的高效路径的中枢来测试这些特定于任务的网络动力学的ECoG模型。我们将使用比常规临床ESM(2-5秒)短得多的刺激序列(200-400ms)来测试这种去激活对言语潜伏期和准确性的影响。这也将测试以较低风险执行ESM的可行性 后放电和癫痫发作，具有更强的功能特异性。第三，我们将比较ECoG网络映射和ESM与手术后真实的语言结果，以比较评估他们的预测能力。虽然这些研究的直接目标是更深入地了解口语产生的皮质网络动力学以及它们如何受到ESM的影响，但这些研究将通过提高ECoG在各自手术前对术中和术中功能标测的临床效用来发挥其最深远和最持久的影响。

 DESCRIPTION (provided by applicant): To avoid post-operative language impairments after surgery for drug-resistant epilepsy, clinicians rely primarily on electrocortical stimulation mapping (ESM), but this can trigger afterdischarges, clinical seizures, or cause uncomfortable sensations, all of which can prevent mapping in some areas. Moreover, ESM can be very time- consuming and the resulting impairment is usually "all-or-none", complicating its interpretation. These practical limitations have long motivated passive electrocorticography (ECoG) as an alternative, or complementary, functional mapping technique that can map function at all sites simultaneously, resulting in significant time savings without adverse side-effects. Recent technical developments also permit ECoG functional mapping to be performed online during testing, but the correspondence between these results and ESM has not been as good for language mapping as it has been for motor mapping. This may be, in part, because even simple language tasks such as object naming or word reading require the recruitment and interaction of widely distributed and potentially redundant cortical areas responsible for different stages of cognitive processing, and because there is no a priori threshold for a magnitude of activation critically important for task performance.. Our overall hypothesis is that the functional importance of a cortical site depends on its role in task-related network dynamics, i.e. the propagation of activation between distributed cortical regions performing the distinct cognitive operations necessary for successful task performance. In this project we will study the task-related network dynamics of spoken word production in order to improve the accuracy of ECoG language maps and to better understand the relationship between ECoG and ESM language maps. First, we will use ECoG to capture the fine temporal dynamics of network propagation during a series of simple word production tasks. We will decompose these network dynamics into temporally cascaded subnets corresponding to functional-anatomical modules responsible for each task's constitutive cognitive operations. In addition, we will identify high centrality noes that serve as hubs facilitating propagation across subnets. Second, we will test these ECoG models of task-specific network dynamics by temporarily deactivating the hubs of high efficiency pathways linking subnets. We will test the effect of this deactivation on verbal latency and accuracy using much briefer (200- 400 ms) stimulation trains than those used during routine clinical ESM (2-5 seconds). This will also test the feasibility of performing ESM with a lower risk of afterdischarges and seizures, and with greater functional specificity. Third, we will compare both ECoG network mapping and ESM to ground-truth post-operative language outcomes in order to comparatively assess their predictive abilities. Although the immediate goal of these studies is to gain deeper insights into the cortical network dynamics of spoken word production and how they are affected by ESM, these studies will exert their most profound and lasting impact by improving the clinical utility of ECoG for both extraoperative and intraoperative functional mapping prior to respective surgery.