Neural Pathways Associated with Sympathetic Neuronal Recruitment in Humans

了解交感放电模式，它们的调节和它们对心血管的影响，是我们实验室的一个主要研究项目。通过交感神经系统，大脑发出的神经活动在频率和组成这些活动的神经元数量上都有所不同。我们最近的研究揭示了构成每一次爆发的各种动作电位，以及在传导速度和招募模式上不同的亚群的存在。具体来说，存在一组大而快速传导的轴突，这些轴突是为高应力情况保留的。什么大脑结构和机制调节这些AP群的招募？交感神经流出的一个强有力的决定因素在于感觉血压的压力感受器。本研究的目的是确定：1)颈动脉窦（颈部）压力感受器的感觉神经如何影响AP募集，2)哪些脑结构参与了AP募集的压力反射控制，3)椎旁神经节在募集过程中的作用，以及4)相对常见的腺苷酸环化酶遗传变异（约7%的白种人）如何通过增强心功能和压力感受器激活来影响AP募集。目前的研究将结合现有的神经显微图分析和大脑激活模式的功能神经影像学，在操纵压力感受器输入和通过交感突触通路的神经传递的药理操作过程中，研究AP募集的神经生理学基础。这项工作将产生新的知识，关于barreflex介导的AP募集和相关修饰物的交感神经流出的影响。此外，该研究将开发新技术，使压力反射刺激能够在磁共振成像环境中进行实验研究。最后，这项研究将有助于长期以来对大脑参与血压控制的信息的需求，新技术和技术将揭示这种机制。

Understanding sympathetic discharge patterns, their modulation¸ and their cardiovascular impact, forms a major program of research in our laboratory. Through the sympathetic nervous system the brain emits bursts of neural activity that vary in frequency and the number of neurons making up the bursts. Our recent research exposed the various action potentials making up each burst and the existence of subpopulations that vary in conduction speed and recruitment patterns. Specifically, there exists a group of large and fast-conducting axons that are reserved for high-stress scenarios. What brain structures, and mechanisms regulate recruitment of these AP groups? A potent determinant of sympathetic outflow lies in the baroreceptors that sense blood pressure. The aims of the present research are to determine: 1) how sensory nerves from baroreceptors in the carotid sinus (neck) affect AP recruitment, 2) what brain structures are involved in the baroreflex control of AP recruitment, 3) the role of the paraspinal ganglia in this recruitment process, and 4) how a relatively common genetic variation (approximately 7% of Caucasians) in adenylate cyclase affects AP recruitment through augmented cardiac function and baroreceptor activation. The current research will combine existing microneurographic analysis of AP recruitment and functional neuroimaging of brain activation patterns, during manipulations of baroreceptor inputs and pharmacological manipulations of neurotransmission through the sympathetic synaptic pathways, to study the neurophysiologic basis of AP recruitment. This work will produce new knowledge regarding baroreflex-mediated AP recruitment and the impact of relevant modifiers of sympathetic outflow. In addition, the research will develop new technologies that enable baroreflex stimuli to be studied experimentally in the magnetic resonance imaging environment. Finally, the research will contribute to the long-standing need for information regarding the brain's involvement in blood pressure control with new techniques and technology to expose such mechanisms.