Vascular Dynamics in Functional MRI

功能 MRI 中的血管动力学

• 批准号: 7407975
• 负责人: THOMAS T LIU
• 金额: $ 27万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7407975
• 关键词: Accounting; Address; Age; Aged, 80 and over; Aging-Related Process; Basic Science; Biomechanics; Blood Vessels; Blood Volume; Brain; Caffeine; Carbon Dioxide; Cerebrovascular Circulation; Cerebrum; Clinical; Complex; Condition; Coupling; Data; Disease; Elasticity; Frequencies; Functional Magnetic Resonance Imaging; Goals; Human; Hypercapnia; Invasive; Knowledge; Lead; Magnetic Resonance Imaging; Measures; Mental disorders; Metabolic; Methods; Modeling; Older Population; Oxygen; Pattern; Pharmaceutical Preparations; Population; Public Health; Range; Rate; Research; Research Personnel; Scanning; Shapes; Signal Transduction; Standards of Weights and Measures; Stimulus; Testing; Theoretical model; Time; Variant; Work; age related; arteriole; blood oxygen level dependent; blood oxygenation level dependent response; clinical application; experience; hemodynamics; improved; indexing; innovation; programs; relating to nervous system; research study; response; tool; vasoactive agent

Project Summary Since its introduction just over a decade ago, functional magnetic resonance imaging (fMRI) has rapidly become an indispensable tool for studies of the working human brain. The vast majority of fMRI studies utilize the blood oxygenation level dependent (BOLD) signal, which reflects the hemodynamic response to neural activity. In these studies, differences in the BOLD signal are typically interpreted as differences in neural activity. However, there is growing evidence that shifts in the baseline vascular state due to factors such as medication, age,and disease can significantly alter the amplitude and shape of the BOLD signal. These factors can increase the variability of the BOLD signal across subjects and experimental conditions and complicate the interpretation of fMRI experiments. The goal of this application is to determine whether non-invasive measures of the baseline vascular state can account for the variability in the BOLD signal that is caused by vasoactive agents and the aging process. The central hypothesis of this proposal, which is supported by strong preliminary data, is that a normalized measure of the power in low frequency components of the BOLD signal, referred to as the 0.1 Hz spectral index, can be used to probe the baseline vascular state and can account for a significant fraction of the variability in the BOLD response. The aims of this proposal are to (1) evaluate the ability of the 0.1 Hz spectral index and other measures of the baseline vascular state to account for the variability in the BOLD response caused by vasoactive agents, and (2) evaluate the ability of these measures to account for age-related variability in the BOLD response. These aims will be achieved using (1) studies that assess the impact of caffeine and hypercapnia on the baseline vascular state and the BOLD response and (2) studies that characterize the baseline vascular state and the BOLD response in young (20 to 45 years old)and old (65 to 95 years old) subjects. Relevance to Public Health The proposed studies are expected to provide the knowledge necessary for the application of the 0.1 Hz spectral index to the improved interpretation of fMRI studies. For example, once the predictive capability of the 0.1 Hz spectral index is demonstrated, it could be applied to studies evaluating the efficacy of various medications for mental illness. By enabling investigators to assess whether medication-related changes in the BOLD response reflect changes in neural activity or are primarily a reflection of the vascular effects of the medication, the 0.1 Hz spectral index would allow investigators to more effectively determine which medications are likely to be of clinical value.

自十多年前推出以来，功能性磁共振成像 功能磁共振成像（fMRI）已迅速成为研究人脑工作的不可或缺的工具。绝大多数 功能磁共振成像研究利用血氧水平依赖（BOLD）信号，它反映了血液动力学 对神经活动的反应。在这些研究中，BOLD信号的差异通常被解释为 神经活动的差异。然而，越来越多的证据表明，基线血管状态的变化 由于诸如药物、年龄和疾病等因素，可以显著改变 粗体信号。这些因素可以增加受试者之间BOLD信号的变异性， 实验条件和复杂的功能磁共振成像实验的解释。这个应用程序的目标是 确定基线血管状态的非侵入性测量是否可以解释变异性 BOLD信号是由血管活性剂和衰老过程引起的。的中心假设 这一建议得到了强有力的初步数据的支持，即， BOLD信号的低频分量（称为0.1Hz频谱指数）可用于 探测基线血管状态，可以解释BOLD中的显著部分变异性 反应本提案的目的是（1）评估0.1 Hz频谱指数和其他 基线血管状态的测量，以解释由以下因素引起的BOLD响应的变异性 血管活性剂，和（2）评估这些措施的能力，以解释年龄相关的变异性， 大胆的回答。这些目标将通过以下方式实现：（1）评估咖啡因影响的研究， 高碳酸血症对基线血管状态和BOLD反应的影响，以及（2）表征 年轻人（20 - 45岁）和老年人（65 - 95岁）的基线血管状态和BOLD反应 科目 与公共卫生的相关性拟议的研究预计将提供必要的知识， 0.1 Hz频谱指数的应用，以改善功能磁共振成像研究的解释。比如一旦 0.1Hz谱指数的预测能力被证明，它可以应用于研究 评估各种药物治疗精神疾病的疗效。通过使调查人员能够评估 药物相关的BOLD反应变化是否反映了神经活动的变化，或者主要是 作为药物对血管影响的反映，0.1 Hz频谱指数将使研究人员能够 更有效地确定哪些药物可能具有临床价值。