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Thrall SF, D'Souza AW, Abrahamson-Durant B, Vianna LC, Limberg JK, Macefield VG, Foster GE. A comparison of wavelet-based action potential detection from the NeuroAmp and the Iowa Bioengineering Nerve Traffic Analysis system. J Neurophysiol 2024; 131:1168-1174. [PMID: 38629146 DOI: 10.1152/jn.00448.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/25/2024] [Accepted: 04/12/2024] [Indexed: 06/01/2024] Open
Abstract
Microneurographic recordings of muscle sympathetic nerve activity (MSNA) reflect postganglionic sympathetic axonal activity directed toward the skeletal muscle vasculature. Recordings are typically evaluated for spontaneous bursts of MSNA; however, the filtering and integration of raw neurograms to obtain multiunit bursts conceals the underlying c-fiber discharge behavior. The continuous wavelet transform with matched mother wavelet has permitted the assessment of action potential discharge patterns, but this approach uses a mother wavelet optimized for an amplifier that is no longer commercially available (University of Iowa Bioengineering Nerve Traffic Analysis System; Iowa NTA). The aim of this project was to determine the morphology and action potential detection performance of mother wavelets created from the commercially available NeuroAmp (ADinstruments), from distinct laboratories, compared with a mother wavelet generated from the Iowa NTA. Four optimized mother wavelets were generated in a two-phase iterative process from independent datasets, collected by separate laboratories (one Iowa NTA, three NeuroAmp). Action potential extraction performance of each mother wavelet was compared for each of the NeuroAmp-based datasets. The total number of detected action potentials was not significantly different across wavelets. However, the predictive value of action potential detection was reduced when the Iowa NTA wavelet was used to detect action potentials in NeuroAmp data, but not different across NeuroAmp wavelets. To standardize approaches, we recommend a NeuroAmp-optimized mother wavelet be used for the evaluation of sympathetic action potential discharge behavior when microneurographic data are collected with this system.NEW & NOTEWORTHY The morphology of custom mother wavelets produced across laboratories using the NeuroAmp was highly similar, but distinct from the University of Iowa Bioengineering Nerve Traffic Analysis System. Although the number of action potentials detected was similar between collection systems and mother wavelets, the predictive value differed. Our data suggest action potential analysis using the continuous wavelet transform requires a mother wavelet optimized for the collection system.
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Affiliation(s)
- Scott F Thrall
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Andrew W D'Souza
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Brendan Abrahamson-Durant
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Lauro C Vianna
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
| | - Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
| | - Vaughan G Macefield
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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Coovadia Y, Schwende BK, Taylor CE, Usselman CW. Limb-specific muscle sympathetic nerve activity responses to the cold pressor test. Auton Neurosci 2024; 251:103146. [PMID: 38181550 DOI: 10.1016/j.autneu.2023.103146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/22/2023] [Accepted: 12/26/2023] [Indexed: 01/07/2024]
Abstract
Recent studies have demonstrated that muscle sympathetic nerve activity (MSNA) responses to isometric exercise differs between active and inactive limbs. Whether limb-dependent responses are characteristic of responses to the cold pressor test (CPT) remains to be established. Therefore, we tested the hypothesis that CPT-induced MSNA responses differ between affected and unaffected limbs such that MSNA in the affected lower limb is greater than MSNA responses in the contralateral lower limb and the upper limb. Integrated peroneal MSNA (microneurography) was measured in young healthy individuals (n = 10) at rest and during three separate 3-min CPTs: the microneurography foot, opposite foot, and opposite hand. Peak MSNA responses were extracted for further analysis, as well as corresponding hemodynamic outcomes including mean arterial pressure (MAP; Finometer). MSNA responses were greater when the microneurography foot was immersed in ice water than when the opposite foot was immersed (38 ± 18 vs 28 ± 16 bursts/100hb: P < 0.01). MSNA responses when the opposite hand was immersed were greater than both the microneurography foot (46 ± 22 vs 38 ± 18 bursts/100hb: P < 0.01) and opposite foot (46 ± 22 vs 28 ± 16 bursts/100hb: P ≤0.01). Likewise, MAP responses were greater during the hand CPT than the microneurography foot (99 ± 9 vs 96 ± 8 mmHg: P < 0.01) and opposite foot CPT (99 ± 9 vs 96 ± 9 mmHg: P < 0.01). These data indicate that (a) upper limbs and (b) immersed limbs elicit greater MSNA responses to the CPT than lower and/or non-immersed limbs.
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Affiliation(s)
- Yasmine Coovadia
- Cardiovascular Health and Autonomic Regulation Laboratory, McGill University, Montreal, Quebec, Canada
| | - Brittany K Schwende
- Cardiovascular Health and Autonomic Regulation Laboratory, McGill University, Montreal, Quebec, Canada
| | - Chloe E Taylor
- School of Health Sciences, Western Sydney University, Sydney, New South Wales, Australia
| | - Charlotte W Usselman
- Cardiovascular Health and Autonomic Regulation Laboratory, McGill University, Montreal, Quebec, Canada.
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Boulton D, Taylor CE, Green S, Macefield VG. The Role of Central Command in the Increase in Muscle Sympathetic Nerve Activity to Contracting Muscle During High Intensity Isometric Exercise. Front Neurosci 2021; 15:770072. [PMID: 34924937 PMCID: PMC8675906 DOI: 10.3389/fnins.2021.770072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
We previously demonstrated that muscle sympathetic nerve activity (MSNA) increases to contracting muscle as well as to non-contracting muscle, but this was only assessed during isometric exercise at ∼10% of maximum voluntary contraction (MVC). Given that high-intensity isometric contractions will release more metabolites, we tested the hypothesis that the metaboreflex is expressed in the contracting muscle during high-intensity but not low-intensity exercise. MSNA was recorded continuously via a tungsten microelectrode inserted percutaneously into the right common peroneal nerve in 12 participants, performing isometric dorsiflexion of the right ankle at 10, 20, 30, 40, and 50% MVC for 2 min. Contractions were immediately followed by 6 min of post-exercise ischemia (PEI); 6 min of recovery separated contractions. Cross-correlation analysis was performed between the negative-going sympathetic spikes of the raw neurogram and the ECG. MSNA increased as contraction intensity increased, reaching mean values (± SD) of 207 ± 210 spikes/min at 10% MVC (P = 0.04), 270 ± 189 spikes/min at 20% MVC (P < 0.01), 538 ± 329 spikes/min at 30% MVC (P < 0.01), 816 ± 551 spikes/min at 40% MVC (P < 0.01), and 1,097 ± 782 spikes/min at 50% MVC (P < 0.01). Mean arterial pressure also increased in an intensity-dependent manner from 76 ± 3 mmHg at rest to 90 ± 6 mmHg (P < 0.01) during contractions of 50% MVC. At all contraction intensities, blood pressure remained elevated during PEI, but MSNA returned to pre-contraction levels, indicating that the metaboreflex does not contribute to the increase in MSNA to contracting muscle even at these high contraction intensities.
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Affiliation(s)
- Daniel Boulton
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Chloe E Taylor
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia.,School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Simon Green
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Vaughan G Macefield
- Neuroscience Research Australia, Sydney, NSW, Australia.,School of Medicine, Western Sydney University, Sydney, NSW, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
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Grotle AK, Macefield VG, Farquhar WB, O'Leary DS, Stone AJ. Recent advances in exercise pressor reflex function in health and disease. Auton Neurosci 2020; 228:102698. [PMID: 32861944 DOI: 10.1016/j.autneu.2020.102698] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 01/11/2023]
Abstract
Autonomic alterations at the onset of exercise are critical to redistribute cardiac output towards the contracting muscles while preventing a fall in arterial pressure due to excessive vasodilation within the contracting muscles. Neural mechanisms responsible for these adjustments include central command, the exercise pressor reflex, and arterial and cardiopulmonary baroreflexes. The exercise pressor reflex evokes reflex increases in sympathetic activity to the heart and systemic vessels and decreases in parasympathetic activity to the heart, which increases blood pressure (BP), heart rate, and total peripheral resistance through vasoconstriction of systemic vessels. In this review, we discuss recent advancements in our understanding of exercise pressor reflex function in health and disease. Specifically, we discuss emerging evidence suggesting that sympathetic vasoconstrictor drive to the contracting and non-contracting skeletal muscle is differentially controlled by central command and the metaboreflex in healthy conditions. Further, we discuss evidence from animal and human studies showing that cardiovascular diseases, including hypertension, diabetes, and heart failure, lead to an altered exercise pressor reflex function. We also provide an update on the mechanisms thought to underlie this altered exercise pressor reflex function in each of these diseases. Although these mechanisms are complex, multifactorial, and dependent on the etiology of the disease, there is a clear consensus that several mechanisms are involved. Ultimately, approaches targeting these mechanisms are clinically significant as they provide alternative therapeutic strategies to prevent adverse cardiovascular events while also reducing symptoms of exercise intolerance.
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Affiliation(s)
- Ann-Katrin Grotle
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, United States of America
| | | | - William B Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States of America
| | - Donal S O'Leary
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, United States of America
| | - Audrey J Stone
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, United States of America.
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Incognito AV, Duplea S, Lee JB, Sussman J, Shepherd AD, Doherty CJ, Cacoilo JA, Notay K, Millar PJ. Arterial baroreflex regulation of muscle sympathetic nerve activity at rest and during stress. J Physiol 2019; 597:4729-4741. [DOI: 10.1113/jp278376] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/31/2019] [Indexed: 12/31/2022] Open
Affiliation(s)
- Anthony V. Incognito
- Department of Human Health and Nutritional SciencesUniversity of Guelph Guelph ON Canada
| | - Sergiu‐Gabriel Duplea
- Department of Human Health and Nutritional SciencesUniversity of Guelph Guelph ON Canada
| | - Jordan B. Lee
- Department of Human Health and Nutritional SciencesUniversity of Guelph Guelph ON Canada
| | - Jess Sussman
- Department of Human Health and Nutritional SciencesUniversity of Guelph Guelph ON Canada
| | - Andrew D. Shepherd
- Department of Human Health and Nutritional SciencesUniversity of Guelph Guelph ON Canada
| | - Connor J. Doherty
- Department of Human Health and Nutritional SciencesUniversity of Guelph Guelph ON Canada
| | | | - Karambir Notay
- Department of Human Health and Nutritional SciencesUniversity of Guelph Guelph ON Canada
| | - Philip J. Millar
- Department of Human Health and Nutritional SciencesUniversity of Guelph Guelph ON Canada
- Toronto General Research Institute Toronto ON Canada
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