Temporal-spatial mapping of cortical networks important for human cognition

 描述（由申请人提供）：为了避免耐药性癫痫手术后的术后语言障碍，临床医生主要依赖于皮层电刺激标测（ESM），但这可能引发后放电、临床癫痫发作或引起不适感觉，所有这些都可能阻止某些区域的标测。此外，无害环境管理可能非常耗时，而且所造成的损害通常是"全有或全无"，使其解释复杂化。这些实际的局限性长期以来一直促使被动皮质电图（ECoG）作为一种替代或补充的功能映射技术，可以同时映射所有部位的功能，从而节省大量时间，而不会产生不良副作用。最近的技术发展还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来说不如对于运动映射来说那么好。这可能是因为，部分，即使是简单的语言任务，如对象命名或单词阅读需要招聘和广泛分布的和潜在的冗余皮层区域负责不同阶段的认知处理的相互作用，因为没有一个先验阈值的激活量至关重要的任务性能。我们的总体假设是，一个皮层网站的功能的重要性取决于它的作用，在任务相关的网络动态，即传播的激活之间的分布式皮层区域执行不同的认知操作所需的成功的任务性能。在这个项目中，我们将研究口语单词产生的任务相关网络动态，以提高ECoG语言地图的准确性，并更好地了解ECoG和ESM语言地图之间的关系。首先，我们将使用ECoG在一系列简单的单词生成任务中捕获网络传播的精细时间动态。我们将把这些网络动态分解成时间级联，对应于负责每个任务的构成性认知操作的功能解剖模块。此外，我们将确定高中心性的noes，作为促进跨网络传播的枢纽。其次，我们将通过暂时停用连接神经元的高效通路的枢纽来测试这些特定任务网络动态的ECoG模型。我们将使用比常规临床ESM（2 - 5秒）更短（200 - 400 ms）的刺激序列来测试这种失活对言语潜伏期和准确性的影响。这也将检验以较低风险执行ESM的可行性 后放电和癫痫发作，并具有更大的功能特异性。第三，我们将比较ECoG网络映射和ESM与地面实况术后语言结果，以比较评估其预测能力。虽然这些研究的直接目标是更深入地了解口语单词产生的皮层网络动态以及它们如何受到ESM的影响，但这些研究将通过改善ECoG在各自手术前用于手术外和术中功能映射的临床效用来发挥其最深远和持久的影响。

 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.