Neuronal Signaling, Network Topology, and Blood Flow Dynamics in Cortex

描述（由申请人提供）：尤里卡的提案解决了神经血管耦合的两个相关问题：1 -将皮质血流动力学与基础血管结构联系起来的设计原则是什么？特别是，微血管是以模块的形式排列还是形成连续体？2 -神经元用来将电活动转化为血流变化（增加和减少）的信号机制是什么？特别是，代谢和血流之间的关系是由抑制性中间神经元控制的血管活性信号分子介导的吗？这些都是脑科学的核心问题，有许多关于动脉运输调节和控制的创新假设。然而，实验方法的缺乏限制了血管单位中心法则的形成和大脑中血液的控制。未来的进展将取决于物理学、神经生理学、分子生物学和实验神经学的概念之间的相互作用。这种相互作用的汇合，拟议的研究的一个基本特征，应该描绘血管网络的紧急属性。我们的方法利用四个独特的，在某些情况下开发的工具：（1）“全光学组织学”和相关的计算程序来重建小鼠大脑的血管结构和细胞结构。这些研究涉及微血管的结构。(2)通过线性和非线性光学相互作用介导的微扰技术，以调节靶血管中的血流。这些研究探讨了脑血流的冗余性，实验性微卒中的测试模型，并为研究脑血流变化对神经元活动的影响提供了一种手段。(3)哨兵细胞，通过转化HEK细胞以响应具有光学读出的外源性递质而形成，以直接测量血管活性分子的模式。(4)在体双光子引导贴片记录和刺激释放血管活性物质的抑制性中间神经元。结合血流的双光子测量，我们可以确定神经元活动和血流之间的定量关系。这些提出的问题涉及正常大脑中血流的基本问题，包括稳态和基于血液的成像技术（如fMRI）的基础，以及功能失调状态下的问题，如微中风和微血管疾病。 公共卫生相关性：大脑中不间断的血液流动对于维持认知的各个方面以及身体功能的稳态至关重要。拟议的工作可能会显着增加我们的理解如何在正常和功能失调状态下调节临界流。这种理解直接影响到对监测基础流量和由心理活动引起的流量变化的诊断的解释。此外，我们的工作可能为微卒中和微血管疾病的潜在治疗提供途径。

DESCRIPTION (provided by applicant): This EUREKA proposal addresses two interlocked questions on neurovascular coupling: 1 - What are the design principles that link cortical blood flow dynamics to the underlying angioachitecture? In particular, is the microvasculature arranged in modules or does it form a continuum? 2 - What are the signaling mechanisms that neurons use to transform electrical activity into changes - both increases and decreases - in blood flow? In particular, is the relation between metabolism and blood flow mediated by vasoactive signaling molecules under the control of inhibitory interneurons? These are central questions in brain science, with many innovative hypotheses on the regulation and control of arterial transport. However, a dearth of experimental approaches has limited the formation of a central dogma on a vascular unit and the control of blood in the brain. Future progress will depend on the strong interplay of concepts from physics, neurophysiology, molecular biology, and experimental neurology. The confluence of this interplay, an essential feature of the proposed studies, should delineate emergent properties of vascular networks. Our approach makes use of four unique and in some cases developing tools: (1) "All Optical Histology" and associated computational procedures to reconstruct the angioarchitecture and cytoarchitecture of the mouse brain. These studies address the structure of the microvasculature. (2) Perturbation techniques, mediated by linear and nonlinear optical interactions, to modulate blood flow in targeted vessels. These studies probe the redundancy of flow, test models of experimental microstroke, and provide one means to study the consequence of changes in flow on neuronal activity. (3) Sentinel cells, formed by transforming HEK cells to respond to exogenous transmitters with an optical read-out, to directly measure patterns of vasoactive molecules. (4) In vivo two-photon guided patch to record from and stimulate inhibitory interneurons that release vasoactive substances. In combination with two photon measurements of blood flow, we can determine quantitative relations between neuronal activity and blood flow. These proposed questions bear on fundamental issues of blood flow in the normal brain including homeostasis and the underpinnings of blood-based imaging techniques such as fMRI - and issues in dysfunctional states - such as microstroke and microvascular diseases. PUBLIC HEALTH RELEVANCE: Uninterrupted blood flow in the brain is essential to maintain all aspects of cognition as well as homeostasis of bodily functions. The proposed work may significantly increase our understanding of how critical flow is regulated in both normal and dysfunctional states. Such understanding bears directly on the interpretation of diagnostics to monitor basal flow and the changes in flow that are induced by mental activity. Further, our work may suggest pathways for the potential treatment of microstroke and microvascular diseases.