Multi-scale mapping of 3D spatial-temporal cortical hemodynamics at the level of

描述(申请人提供)：单个神经元血管对感觉刺激的动力学反应对于形成对功能成像技术(如功能磁共振成像(FMRI))的机械理解以及了解神经血管功能障碍(如中风和痴呆症)至关重要。为了达到这一目标，我们建议在单个微动脉和毛细血管的水平上，通过一个重要的三维体积来表征刺激诱发的脑血流动力学反应。此外，我们将把这种特征与潜在的神经元电活动、血管构筑和线粒体密度联系起来。以大鼠可控震颤感觉皮层为模型系统。双光子激光扫描显微镜(TPLSM)，结合标记血腔的染料，以及相关的非线性光学技术--全光组织学--是我们的主要技术。作为拟议测量的先决条件，我们将改进TPLSM的能力，使其能够快速评估多条血管。这将使我们能够在2-3mm3的体积内以微米级的分辨率表征血流和血管直径，以及不同血管中血流的相关性。 我们的分析包括三个方向。 三类血管，即表面交通小动脉、穿透小动脉和表面下微血管在触觉单一触觉刺激下的直径和流动动力学的动态特征。 通过体内血管测量，体外重建整个研究区域的准确血管结构，然后绘制线粒体相对于微血管系统的三维密度图。 我们的结果将至少揭示： 单个血管直径和血流变化的时间动力学特征，例如双相与单相的特征。 血管的反应依赖于它离神经元活动中心的距离，它与主要的表面供血动脉或穿透小动脉的连通性，以及它相对于局部代谢需要的位置，如线粒体密度所揭示的。 这项工作将弥合宏观功能成像技术(如功能磁共振成像)和微观理解单个血管对神经元激活的反应之间的关键差距。中风、血管疾病和痴呆症都是与大脑血流受损有关的功能障碍状态。我们的工作将定义流动的正常状态，并与正常状态的中断有关。它将有助于定义基于光学和MRI的诊断，用于检测功能障碍和临床上合适的介入治疗。

DESCRIPTION (provided by applicant): The dynamics response of individual neuronal vessels to sensory-stimuli is crucial to form a mechanistic understanding of functional imaging technologies, such as functional MRI (fMRI), as well as for understanding neurovascular dysfunction, as occurs in stroke and dementia. Toward this goal, we propose to characterize the stimulus-evoked cerebral hemodynamic response on the level of single arterioles and capillaries throughout a significant three-dimensional volume. Further, we will relate this characterization to the underlying neuronal electrical activity, the angioarchitecture, and the mitochondria density. Vibrissa sensory cortex of rat serves as our model system. Two-photon laser scanning microscopy (TPLSM), in conjunction with dyes that label the blood lumen, and all-optical histology, a related nonlinear optics technique, serve as our primary technology. As a prerequisite to the proposed measurements, we will improve the capability of TPLSM to allow rapid assessment of multiple blood vessels. This will allow us to characterize blood flow and blood vessel diameter at micrometer resolution throughout a 2 - 3 mm3 volume, along with correlations along flow in different vessels. Our analysis consists of three directions. Dynamical characterization of the diameter and flow dynamics of three classes of vessels, i.e., surface communicating arterioles, penetrating arterioles, and subsurface microvessels, in response to tactile single vibrissa stimulation. Ex vivo reconstruction of the exact angioarchitecture throughout the region of study by the in vivo vascular measurements, followed by three-dimensional mapping of the mitochondria density relative to the microvasculature. Our results will reveal, at a minimum: The characteristics, e.g., biphasic versus monophasic, of the temporal dynamics of the vessel diameter and blood flow changes of individual vessels. The dependence of the responses of a vessel on its distance from the center of the neuronal activity, its connectivity to major surface feeding arteries or penetrating arterioles, and its position relative to the local metabolic need as revealed by the mitochondria density. This work will bridge the critical gap between macroscopic functional imaging technologies such as fMRI and the microscopic understanding of single vessel responses to the neuronal activation. Stroke, vascular disease, and dementia are all dysfunctional states that relate to compromised cerebral blood flow. Our work will define the normal state of flow and bears on disruption to the normal state. It will help define optical- and MRI-based diagnostics for the detection of dysfunction and clinically appropriate interventionist therapies.