Learning Related Modulation of Resting Brain Metabolism

描述(由申请人提供)： 功能神经成像技术，如血氧水平依赖(BOLD)磁共振成像和正电子发射断层扫描(PET)，揭示了任务诱导的神经元活动和新陈代谢的变化。目前这项研究的目的是了解人类在任务诱导后基线大脑活动的变化。具体地说，目前的研究将描述学习隐含的视觉运动旋转任务后新陈代谢(通过PET检测)和大脑功能连接性(通过功能磁共振成像检测)的变化。这项研究将为了解大脑的内在结构、学习对大脑代谢的影响提供重要证据，并为研究大脑功能中的代谢缺陷提供新的途径。实验的重点将是具体测试这一假说，即短暂的、与任务相关的局部活动变化会导致静息大脑中有氧糖酵解的长期增加。目前，功能成像技术依赖于任务相关刺激前后真实基线状态的假设。虽然这一假设允许进行简单的数据分析，但在复杂的刺激下，已有全球糖代谢变化的报道。所有外部刺激都会导致大脑结构和功能的轻微变化；这些变化可能是简单或复杂的视觉、视觉运动或认知任务造成的。将信息编码成神经元回路的缺陷或提取此类信息的缺陷是一个具有重大临床意义的重要领域，特别是由于老龄化人口中阿尔茨海默病的负担日益加重。具体目的是：1)表征旋转学习对随后的基线葡萄糖代谢(通过FDG-PET测量)和功能连接(通过自发fMRI BOLD信号的变化测量)的影响。确定基线代谢改变和特定任务活动增加的区域特异性。2)描述旋转学习进入有氧糖酵解或氧化磷酸化后的持续性代谢变化。通过PET测量局部血流量、氧气消耗和葡萄糖消耗，确定整个大脑的氧气-葡萄糖指数(OGI)。确定代谢变化(OGI)和自发BOLD活动之间的相关性。这项研究项目的目的是使用脑功能成像来准确了解学习后基线大脑活动的变化。这项研究将提供有关大脑如何结构以及阿尔茨海默氏症和中风等疾病如何改变大脑活动和新陈代谢的重要信息。

DESCRIPTION (provided by applicant): Functional neuroimaging techniques such as blood-oxygen level dependent (BOLD) magnetic resonance imaging and positron emission tomography (PET) reveal task-induced alterations in neuronal activity and metabolism. The objective of the current research is to understand the changes in baseline brain activity following task induction in humans. Specifically, the current study will characterize alterations in metabolism (detected via PET) and functional connectivity of the brain (detected via fMRI) following learning of an implicit visuomotor rotation task. This research will provide important evidence about the intrinsic structure of the brain, the effect of learning on brain metabolism, and provide new avenues to research metabolic defects in brain function. The experimental focus will be to specifically test the hypothesis that transient, task-related local activity changes result in long-term increases in aerobic glycolysis in resting brain. Currently, functional imaging techniques rely upon the assumption of a true baseline state both before and after task-related stimulation. While this assumption allows for simple data analysis, global alterations in glucose metabolism have been reported following complex stimuli. All external stimuli result in slight alterations in brain structure and function; these alterations could result from simple or more complex visual, visuomotor, or cognitive tasks. Defects in the encoding of information into neuronal circuits or defects in retrieval of such information represent an important area with great clinical relevance, especially due to the increasing burden of Alzheimer's disease in the aging population. The specific aims are to: 1) Characterize the effect of rotation learning upon subsequent baseline glucose metabolism (measured via FDG-PET) and functional connectivity (measured via alterations in spontaneous fMRI BOLD signal). Determine regional specificity of baseline metabolic alterations and task-specific activity increases. 2) Characterize the persistent metabolic changes following rotation learning into aerobic glycolysis or oxidative phosphorylation. Determine the oxygen-glucose-index (OGI) throughout the brain using measurements of regional blood flow, oxygen consumption, and glucose consumption via PET. Determine correlations between metabolic changes (OGI) and spontaneous BOLD activity. The objective of this research project is to use functional brain imaging to understand exactly how baseline brain activity changes after learning. This research will provide important information about how the brain is structured and how diseases such as Alzheimer's and stroke may alter brain activity and metabolism.