Cortical organization of object knowledge before and after brain surgery

描述(由申请人提供)：切除固有脑瘤的手术可能会导致意外的认知障碍。尤其是当健康组织必须切除(皮质切除)才能接触到肿瘤时。皮质切除对神经功能和认知结果的影响仍然知之甚少。近年来，在没有明显刺激或任务的情况下，利用功能磁共振成像(FMRI)采集的数据研究脑区之间的动态相互作用，为研究脑内固有肿瘤根治性切除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开发，因为可以从认知能力不同的患者那里收集数据，作为他们标准临床评估的一部分。根据物体的功能(如叉子、锤子、铅笔)识别和使用物体的能力需要在颞叶和顶叶皮质的多个脑区进行协调处理。在切除颞叶或顶叶脑瘤的神经外科手术后，这些认知能力可能会受到影响。拟议的研究计划使用静息fMRI来研究支持共同对象知识的皮质网络的组织。患有颞叶和顶叶脑瘤的患者将接受基于刺激的静息fMRI扫描，并在手术前和手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定义的感兴趣区(ROI)，将在支持对象知识的颞顶皮质网络内量化功能连接。在PI先前研究的基础上，提出了特定的假设，即连接的预期变化作为脑肿瘤的位置和切除肿瘤的手术入路的性质的函数。然后将手术后的数据与手术前的数据进行比较，并将功能连接性的变化与认知能力的变化联系起来，以检验这些假设。为此，开发了一种新的方法，将病变-症状图的分析工具应用于fMRI连通性图，以便能够得出全脑图，显示功能连通性的变化如何与认知表现的变化相关。这项研究计划有两个目标。首先，它将向神经外科医生产生一种关于患者结果的新型反馈，这将为接受固有脑瘤切除的患者的手术计划提供信息。其次，对支持视觉物体识别和物体使用的大脑功能网络的假设进行了测试，并得出了关于帮助这些复杂行为的大脑过程的因果推断。 公共卫生相关性：功能磁共振成像用于测试神经外科患者中优势半球脑肿瘤患者大脑皮质网络的可塑性假说，这些网络支持客体知识。除了研究形成大脑组织的制约因素外，还将制定一个预后指标来规划皮质切除的位置。

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.