Cortical organization of object knowledge before and after brain surgery

描述（由申请人提供）：切除内在脑肿瘤的手术可能导致意想不到的认知障碍。这在必须切除健康组织（皮质切除术）以接近肿瘤时尤其如此。皮质切除术对神经功能和认知结果的影响仍然知之甚少。利用功能磁共振成像（fMRI）研究脑区域之间动态相互作用的最新进展，在受试者休息时，没有明显的刺激或任务，为研究根治性脑肿瘤的神经后果开辟了新的视野。这种成像模式非常适合在临床环境中应用和发展，因为数据可以从异质性认知能力的患者中收集，作为其标准临床评估的一部分。根据功能识别和使用物体的能力（例如，叉子、锤子、铅笔）需要在颞叶和顶叶皮层的多个大脑区域协调处理。在切除颞叶或顶叶脑肿瘤的神经外科手术后，这些认知能力可能会受到损害。拟议的研究计划使用静息功能磁共振成像来研究支持普通物体知识的皮层网络的组织。患有颞叶和顶叶脑肿瘤的患者将接受基于刺激和静息的功能磁共振成像扫描，并在手术前和术后接受详细的神经心理测试。使用基于刺激的功能磁共振成像（fMRI）定义的兴趣区域（roi），将在支持对象知识的颞-顶叶皮质网络中量化功能连接。在pi先前研究的基础上，提出了关于连接预期变化作为脑肿瘤位置和切除肿瘤手术入路性质的函数的具体假设。然后，通过比较手术后和手术前的数据，并将功能连接的变化与认知能力的变化联系起来，对这些假设进行检验。为此，开发了一种新的方法，将病变-症状映射的分析工具应用于fMRI连接图，以便能够获得显示功能连接变化如何与认知表现变化相关的全脑图。这个研究项目有两个目的。首先，它将为神经外科医生提供一种关于患者结果的新型反馈，这将为接受内在脑肿瘤切除术的患者提供手术计划。其次，对支持视觉对象识别和对象使用的功能性大脑网络的假设进行了测试，并得出了支持这些复杂行为的大脑过程的因果推论。

DESCRIPTION (provided by applicant): Surgery for removal of intrinsic brain tumors can lead to unintended cognitive impairments. This is particularly the case when healthy tissue must be resected (corticectomy) in order to access the tumor. The consequences of corticectomy for neural function and cognitive outcome remain poorly understood. Recent advances in studying dynamic interactions among brain regions using functional magnetic resonance imaging (fMRI) data collected while subjects are at rest, with no overt stimulus or task, open up new horizons for studying the neural consequences of radical resection of intrinsic brain tumors. This imaging modality is well suited for application and development within a clinical setting, as data may be collected from patients of heterogeneous cognitive abilities as part of their standard clinical assessment. The ability to recognize and use objects according to their function (e.g., fork, hammer, pencil) requires coordinated processing across multiple brain regions in temporal and parietal cortex. Those cognitive abilities can be compromised after neurosurgery for removal of temporal or parietal lobe brain tumors. The proposed research program uses resting fMRI to study the organization of the cortical networks supporting knowledge of common objects. Patients with brain tumors in the temporal and parietal lobes will be scanned with stimulus- based and resting fMRI and will undergo detailed neuropsychological testing before surgery and after surgery. Using regions of interest (ROIs) defined with stimulus-based fMRI, functional connectivity will be quantified within the temporal-parietal cortical network supporting object knowledge. On the basis of the PIs previous research, specific hypotheses are advanced about anticipated changes in connectivity as a function of the location of the brain tumor and the nature of the surgical approach for removal of the tumor. Those hypotheses are then tested by comparing the post-surgery data to the pre-surgery data, and relating changes in functional connectivity to changes in cognitive abilities. To this end, a new method is developed that applies the analytical tool of lesion-symptom mapping to fMRI connectivity maps in order to be able to derive whole brain maps showing how changes in functional connectivity are related to changes in cognitive performance. This research program serves two goals. First, it will generate a new type of feedback about patient outcome to neurosurgeons that will inform surgical planning in patients undergoing resection of intrinsic brain tumors. Second, hypotheses about the functional brain networks that support visual object identification and object use are tested, and causal inferences are drawn about the brain processes that subserve those complex behaviors. PUBLIC HEALTH RELEVANCE: Functional MRI is used to test hypotheses about plasticity in the cortical networks supporting object knowledge in neurosurgery patients with dominant hemisphere brain tumors. In addition to studying the constraints that shape brain organization, a prognostic metric will be developed for planning the location of corticectomies.