Functional near-infrared imaging using the phase of hemodynamic oscillations

描述(由申请人提供)：这个项目探索了一种新的方法的潜力，用近红外光谱研究大脑的功能。我们假设，脑氧合血红蛋白和脱氧血红蛋白浓度波动之间的相位关系提供了以下信息：(1)与大脑激活相关的血流动力学和氧合相关过程的相互作用，以及(2)涉及不同皮质区域的功能连接网络。具体地说，在这个项目中，我们将使用一种新的基于相量的血流动力学振荡分析和表示方法，对先前在整夜睡眠研究中收集的数据进行新的分析。这一新的分析将使我们能够检验这样的假设，即与不同睡眠阶段相关的血液动力学条件在0.1赫兹(迈耶波)附近的频率上导致氧合血红蛋白的自发振荡和脱氧血红蛋白浓度之间的不同的相位关系。我们还将检验这一假设，即氧合血红蛋白和脱氧血红蛋白浓度的变化有不同的相对阶段，取决于激活的皮质区域和/或刺激方案。最后，我们将进行试点测量，以测试这种基于阶段的新方法在研究大脑功能连接网络方面的潜力。该项目可能带来一种新的脑功能研究方法，并探索功能磁共振成像无法获取的信号，涉及顺磁和抗磁血红蛋白物种。 公共卫生相关性：我们提出了一种新的近红外功能成像方法，该方法基于氧合和脱氧血红蛋白组织浓度的振荡时相。这一方法将提供有关大脑静息和激活状态下血流动力学和代谢过程的空间和时间相互作用的信息。这些信息可以在促进对神经血管耦合、功能连接和大脑自动调节的理解方面发挥关键作用，这些都是开发重要的功能成像工具的关键方面。

DESCRIPTION (provided by applicant): This project explores the potential of a novel approach to functional studies of the brain with near-infrared spectroscopy. We hypothesize that the phase relationship between oscillations of cerebral oxy-hemoglobin and deoxy-hemoglobin concentrations provide information about (1) the interplay of hemodynamic and oxygenation-related processes that are associated with brain activation, and (2) functional connectivity networks involving distinct cortical areas. Specifically, in this project we will perform a new analysis of data collected previously in a full-night sleep study using a novel phasor-based analysis and representation of hemodynamic oscillations. This new analysis will allow us to test the hypothesis that hemodynamic conditions associated with different sleep stages induce different phase relationship between spontaneous oscillations of oxy-hemoglobin and deoxy-hemoglobin concentrations at frequencies around 0.1 Hz (Mayer waves). We will also test the hypothesis that oxy-hemoglobin and deoxy-hemoglobin concentration changes have different relative phases depending on the cortical area activated and/or the stimulation protocol. Finally, we will perform pilot measurements to test the potential of this new phase-based method in studying functional connectivity networks in the brain. This project can lead to a novel approach to functional brain studies, and explores signals that are not accessible with functional magnetic resonance imaging, involving both paramagnetic and diamagnetic hemoglobin species. PUBLIC HEALTH RELEVANCE: We propose a novel approach to near-infrared functional imaging based on the phase of oscillations of oxy- and deoxy-hemoglobin tissue concentrations. This approach will provide information on the spatial and temporal interplay of hemodynamic and metabolic processes occurring in resting and activated states of the brain. Such information can play a critical role in advancing the understanding of neurovascular coupling, functional connectivity, and cerebral autoregulation, all critical aspects for the development of a significant functional imaging tool.