The Hemodynamic Response to Brain Activation

对大脑激活的血流动力学反应

• 批准号: 6946794
• 负责人: RICHARD BRUCE BUXTON
• 金额: $ 36.1万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-30 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6946794
• 关键词: bioenergetics; biological signal transduction; brain circulation; brain electrical activity; clinical research; functional magnetic resonance imaging; hemodynamics; human subject; neural information processing; neuroanatomy; neurophysiology; oxygen; visual stimulus

DESCRIPTION (provided by applicant): Functional magnetic resonance imaging (fMRI) is an essential part of many basic neuroscience studies, providing a powerful tool for mapping patterns of activation in the working human brain. However, these techniques have been slow to move into the clinical realm, due both to a lack of sensitivity of current techniques and also to a lack of understanding of the nature and variability of the local hemodynamic response and the associated Blood Oxygenation Level Dependent (BOLD) signal response to activation. Because the hemodynamic response (HR) is the key physiological process in the brain linking neural activity with blood flow and energy metabolism, a detailed characterization of the HR has the potential to provide a powerful probe for early assessment of disease and for investigations of the pathophysiology involved. There are three problems blocking progress in the development of these clinical applications: 1) The BOLD effect is highly variable even in healthy subjects, making it difficult to detect meaningful differences between individual subjects, 2) Nonlinearities in the BOLD response introduce a strong dependence on the experimental design used, and 3) The interpretation of alterations in the BOLD response observed in a disease population is intrinsically ambiguous because the BOLD effect depends on combined changes in cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2) and cerebral blood volume (CBV). The basis for this proposal is the hypothesis that simultaneous measurement of the CBF response and the BOLD response using arterial spin labeling (ASL) techniques, when analyzed with a dynamic model for the HR, will greatly expand the specificity and reliability of HR measurements. To validate the feasibility of this approach we will: 1) verify that the proposed model is adequate for describing the CBF and BOLD responses by testing whether the model parameters calculated with one experimental design allow accurate prediction of the responses with a different experimental design; 2) determine the reproducibility of the HR parameter measurements in repeated studies on the same subject, and assess the variability of the parameters in young healthy adults; 3) determine the degree to which variations in resting CBF, CMRO2 changes and CBV changes contribute to the variability of the BOLD response, and 4) determine whether there is a significant variation in the HR parameters with healthy development and aging.

描述（由申请人提供）：功能磁共振成像（fMRI）是许多基本神经科学研究的重要组成部分，为工作人脑中的激活模式提供了强大的工具。但是，由于缺乏当前技术的敏感性以及对局部血液动力学反应的性质和可变性的理解以及相关的血液氧合水平（BOLD）信号反应对激活的激活，因此这些技术进入临床领域的速度很慢。 由于血液动力学反应（HR）是大脑中神经活动与血流和能量代谢的关键生理过程，因此对HR的详细表征有可能为疾病的早期评估和对涉及病理生理学的研究提供强大的探测。这些临床应用的发展有三个问题：1）即使在健康受试者中，大胆的效果也很大变化，使得很难检测到个体受试者之间的有意义的差异，2）大胆反应中的非线性在强烈的依赖中引入了对所使用的实验设计的强烈依赖，而3）3）在疾病人群中的大胆反应中的变化对大胆效应的概述，因为在疾病中，cc上的综合效应是综合效应，因为ccy是综合效应的，因为它是综合的效果。 （CBF），氧（CMRO2）和脑血容量（CBV）的大脑代谢率。 该提案的基础是假设，即使用动脉自旋标记（ASL）技术同时测量CBF响应和BOLD响应，当用HR的动态模型进行分析时，将大大扩展HR测量值的特异性和可靠性。为了验证这种方法的可行性，我们将：1）验证提出的模型是否足以描述CBF和通过测试使用一种实验设计计算的模型参数可以通过不同的实验设计进行准确预测响应的模型参数； 2）确定对同一受试者的重复研究中HR参数测量的可重复性，并评估年轻健康成年人参数的变异性； 3）确定静息CBF，CMRO2变化和CBV变化的变化有助于大胆响应的变异性的程度，4）确定与健康发育和衰老有关的HR参数是否存在显着差异。