An open-source application for the standardized burst identification from the integrated muscle sympathetic neurogram

Abstract

Muscle sympathetic nerve activity (MSNA) can be acquired from humans using the technique of microneurography. The resulting integrated neurogram displays pulse-synchronous bursts of sympathetic activity which undergoes processing for standard MSNA metrics including burst frequency, height, area, incidence, total activity and latency. The procedure for detecting bursts of MSNA and calculating burst metrics is tedious and differs widely amongst laboratories world-wide. We sought to develop an open-source, cross-platform web application that provides a standardized approach for burst identification and a tool to increase research reproducibility for those measuring MSNA. We compared the performance of this web application against a manual scoring approach under conditions of rest, chemoreflex activation (N = 9, 20 min isocapnic hypoxia), and metaboreflex activation (N = 13, 2 min isometric handgrip exercise and 4 min post exercise circulatory occlusion). The intraclass correlation coefficient (ICC) indicated good to strong agreement between scoring approaches for burst frequency (ICC = 0.92 - 0.99), incidence (ICC = 0.94 - 0.99), height (ICC = 0.76 - 0.88), total activity (ICC = 0.85 - 0.99), and latency (ICC = 0.97 - 0.99). Agreement with burst area was poor to moderate (ICC = 0.04 - 0.67) but changes in burst area were similar with chemoreflex and metaboreflex activation. Scoring using the web application was highly efficient and provided data visualization tools which expedited data processing and the analysis of MSNA. We recommend the open-source web application be adopted by the community for the analysis of MSNA.

Action potential amplitude and baroreflex resetting of action potential clusters mediate hypoxia‐induced sympathetic long‐term facilitation

“…Multiunit recordings of postganglionic efferent MSNA were quantified using microneurography (Nerve Traffic Analysis System Model 662C‐4, Absolute Designs, Iowa City, IA, USA) as described previously (Foster et al., 2021; Nardone et al., 2020; Notay et al., 2016). Briefly, a tungsten microelectrode (10 mΩ, tip diameter 5−10 μm, 25−35 mm long, Fredrick Haer, Bowdoinham, ME, USA) was inserted percutaneously into the fibular nerve, with a reference electrode inserted 2−3 cm away.…”

Acute hypoxia elicits lasting reductions in the sympathetic action potential transduction of arterial blood pressure in males

“…Multiunit postganglionic efferent MSNA was quantified using microneurography (Nerve Traffic Analysis System Model 662C‐4, Absolute Designs, Iowa City, IA) as described previously (Foster et al., 2021; Nardone et al., 2020; Notay et al., 2016). Briefly, a tungsten microelectrode (10 mΩ, tip diameter 5–10 μm, 25–35 mm long, Fredrick Haer, Bowdoinham, ME) was inserted percutaneously into muscle nerve fascicles of the fibular nerve, with a reference electrode inserted 2–3 cm away.…”

“…Muscle sympathetic bursts were inspected (B.M.S.) using an open‐source application for processing and analysing MSNA (Foster et al., 2021). Muscle sympathetic bursts were determined using internationally accepted guidelines (White et al., 2015) and were classified based on the following criteria: occurred 1.2–1.4 s after a QRS complex, had a signal‐to‐noise ratio of >3:1, and exhibited a triangular‐shaped morphology.…”