Neural Pathways Associated with Sympathetic Neuronal Recruitment in Humans

了解交感神经放电模式，它们的调制方式及其对心血管的影响，是我们实验室的一个主要研究项目。通过交感神经系统，大脑发出神经活动的爆发，这些活动的频率和组成爆发的神经元的数量不同。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。具体地说，存在一组大的、快速传导的轴突，专为高压力情况而保留。是什么大脑结构和机制控制着这些AP群体的招募？交感神经流出的一个强有力的决定因素在于感知血压的压力感受器。本研究的目的是确定：1)颈动脉窦(颈部)压力感受器感觉神经如何影响AP招募；2)什么脑结构参与AP招募的压力反射控制；3)脊旁神经节在AP招募过程中的作用；4)腺苷环化酶中一个相对常见的遗传变异(约7%的高加索人)如何通过增强心功能和压力感受器激活来影响AP招募。目前的研究将结合已有的AP募集的显微神经学分析和脑激活模式的功能神经成像，在操纵压力感受器输入和药物调控交感神经突触通路的神经传递过程中，研究AP募集的神经生理学基础。这项工作将对压力感受性反射介导的AP募集和交感神经流出的相关调节剂的影响产生新的认识。此外，这项研究将开发新的技术，使压力感受器反射刺激能够在磁共振成像环境中进行实验研究。最后，这项研究将有助于通过新的技术和技术来揭示大脑参与血压控制的机制，从而有助于长期需要有关大脑参与血压控制的信息。

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.