Neural Population Dynamics in Porcine Stellate Ganglion in Normal and Heart Failure States

Abstract

Neural populations in the sympathetic nervous system are involved in hierarchical closed loop control of the heart involving multiple intrathoracic ganglia. This thesis expands on their processing capabilities with a focus on the stellate ganglion (SG). To examine SG cardiopulmonary processing, long extracellular recordings were made from the left SG of anesthetized healthy and heart failure (HF) pigs. Population analysis depended upon a novel spike detection algorithm. Spatial coherence between populations was estimated using events with most pairs of recorded sites displaying high co-activity. Dynamic linkages between populations and cardiopulmonary information were derived from a novel, neural specificity metric. SG neuronal activity showed an integration of cardiopulmonary information. Neural specificity to cardiopulmonary markers is biased, relative to random sampling, toward specific LVP regions in both animal groups. HF animals showed higher population spatial coherence coupled to greater variation in neural specificity compared to healthy pigs in baseline and during instances of high spatial coherence. These findings reveal a network whose linkage to cardiopulmonary dynamics is strongly dependent on animal status.