Sympathetic Neural Recruitment, Modulation, and Vascular Coupling in Humans

研究项目目标：了解交感神经系统（SNS）在面对生理压力时控制血压和调节血流分布的神经通信策略。我们正在测试的工作假设，SNS表达了一个复杂的，但确定性的语言表达在其招聘的各种家庭的神经元，以及修改的时间的神经元放电模式。** 背景：生存取决于外部和内部应激源与重要内脏器官的快速准确沟通，导致功能变化以应对压力。例如，当你站起来时，采取纠正措施以防止血压下降，这需要身体中的神经传感器之间的复杂联系，这些传感器将问题告知大脑，然后修改交感神经活动（SNA）的流出，以调整心脏和血管的功能，以保护血压。一般来说，神经系统依赖于神经放电的模式来精确地传达刺激的细节。然而，我们对SNS用于交流和纠正压力引起的生理紊乱的神经“语言”的理解仍然非常肤浅。使用人类的直接神经记录，我们已经表征了复杂的SNS募集策略，包括i）在基线时已经募集的轴突的发射率的修改，ii）在压力期间募集额外的神经群体，以及iii）这些轴突发射模式的定时的变化。我们现在的目标是提高我们对控制这些神经募集模式的机制的理解，以及通过血管收缩模式测量血管对它们的解释。研究目的：1）确定与特定SNA模式相关的大脑区域和可能的神经控制机制，2）开发以滴定方式操纵这些通信模式的方法，以进一步研究感觉和交感神经系统之间的相互作用，以及3）量化SNA信号如何在血管收缩的幅度方面被血管解释。使用各种生理应激源，我们将评估SNA动作电位募集（显微神经成像），功能性脑激活（神经成像）和肌肉血流量（超声和弥散相关光谱）之间的关系。这些研究是非常新颖的，并解决了一个基本的自我平衡原则，提高动物生存通过急性和慢性适应压力。

Research Program Objective: Understand the neurological communication strategies used by the sympathetic nervous system (SNS) to control blood pressure and regulate the distribution of blood flow in the face of physiological stress. We are testing the working hypothesis that the SNS expresses a complex but deterministic language expressed in its recruitment of various families of neurons as well as modifications of the timing of the neuronal firing patterns. ******Background: Survival depends upon rapid and accurate communication of external and internal stressors to vital internal organs, leading to functional changes to deal with the stress. For example, corrective action taken to keep blood pressure from falling when you stand up requires an intricate linkage between neural sensors in your body that inform the brain about the problem which then modifies the outflow of sympathetic nerve activity (SNA) to adjust the function of heart and blood vessels to protect blood pressure. In general, neural systems rely on patterns of neural firing to communicate precisely the details of the stimulus. However, our understanding of the neural “language” used by the SNS to communicate and correct stress-induced physiological disturbances remains very superficial. Using direct neural recordings in humans, we have characterized complex SNS recruitment strategies, including i) modifications of firing rate of axons already recruited at baseline, ii) recruitment of additional neural populations during stress, and iii) variations in the timing of these axonal firing patterns. We now aim to improve our understanding of the mechanisms controlling these neural recruitment patterns as well as their interpretation by blood vessels as measured in their patterns of vasoconstriction.******Research Aims: 1) Determine the brain regions and possible neural control mechanisms associated with the specific SNA patterns, 2) Develop methods that manipulate these communication patterns in a titrated manner to study further the interactions between sensory and sympathetic neural systems, and 3) Quantify how SNA signals are interpreted by blood vessels in terms of the magnitude of vasoconstriction. Using a variety of physiological stressors, we will assess relationships between SNA action potential recruitment (microneurography), functional brain activation (neuroimaging), and muscle blood flow (ultrasound and diffusive correlative spectroscopy). These studies are highly novel and address a fundamental homeostatic principle that enhances animal survival through acute and chronic adaptations to stress.