Meeting Abstract

12.4  Thursday, Jan. 3  Measuring the Fight-or-Flight response with Heart Rate Variability analysis DICKENS, Molly J.*; CYR, Nicole E; ROMERO, L. Michael; Tufts University; Wellesley University; Tufts University molly.dickens@tufts.edu

While the Fight-or-Flight response is a major component of stress physiology, measuring this response is extremely difficult in wild species. One solution is to measure a component of the response such as heart rate. Heart rate, however, is controlled by two inputs � both the stress-stimulated Sympathetic Nervous System (SNS) as well as the non-stress stimulated Parasympathetic Nervous System (PNS). Traditionally, only the SNS is thought to be the input connected to the Fight-or-Flight response, so that using Heart rate (HR) as an index for Fight-or-Flight requires being able to determine the relative contributions of the SNS and PNS. Since the PNS creates variability in the time between heartbeats and the SNS makes beats more regular, a decrease in variability between beats indicates SNS control. Using European Starlings (Sturnus vulgaris), our study examined this analysis method, termed Heart Rate Variability (HRV), to distinguish between the two sources of control over heart rate. HRV was measured by determining the variation in distance between each consecutive R wave (R-R variability). In order to isolate the components of heart rate stimulation, we injected a SNS blocker (propranolol) and a PNS blocker (atropine) and examined changes in both baseline and acute stress-induced Heart rate (HR) and HRV. Results indicated that a stress-induced increase in heart rate is a result of increased SNS input, as predicted from studies on mammalian species. This study enabled us to make the distinction between PNS and SNS control over the autonomic and stress-induced HR and to confirm that HRV is a valid method to use for Fight-or-Flight response research in passerines.