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Bush NE, Ramirez JM. Latent neural population dynamics underlying breathing, opioid-induced respiratory depression and gasping. Nat Neurosci 2024; 27:259-271. [PMID: 38182835 PMCID: PMC10849970 DOI: 10.1038/s41593-023-01520-3] [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: 11/30/2022] [Accepted: 11/06/2023] [Indexed: 01/07/2024]
Abstract
Breathing is vital and must be concurrently robust and flexible. This rhythmic behavior is generated and maintained within a rostrocaudally aligned set of medullary nuclei called the ventral respiratory column (VRC). The rhythmic properties of individual VRC nuclei are well known, yet technical challenges have limited the interrogation of the entire VRC population simultaneously. Here we characterize over 15,000 medullary units using high-density electrophysiology, opto-tagging and histological reconstruction. Population dynamics analysis reveals consistent rotational trajectories through a low-dimensional neural manifold. These rotations are robust and maintained even during opioid-induced respiratory depression. During severe hypoxia-induced gasping, the low-dimensional dynamics of the VRC reconfigure from rotational to all-or-none, ballistic efforts. Thus, latent dynamics provide a unifying lens onto the activities of large, heterogeneous populations of neurons involved in the simple, yet vital, behavior of breathing, and well describe how these populations respond to a variety of perturbations.
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Affiliation(s)
- Nicholas Edward Bush
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.
- Department of Pediatrics, University of Washington, Seattle, WA, USA.
- Department of Neurological Surgery, University of Washington, Seattle, WA, USA.
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2
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Nuding SC, Segers LS, Iceman K, O'Connor R, Dean JB, Valarezo PA, Shuman D, Solomon IC, Bolser DC, Morris KF, Lindsey BG. Hypoxia evokes a sequence of raphe-pontomedullary network operations for inspiratory drive amplification and gasping. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.07.566027. [PMID: 37986850 PMCID: PMC10659307 DOI: 10.1101/2023.11.07.566027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Hypoxia can trigger a sequence of breathing-related behaviors, from tachypnea to apneusis to apnea and gasping, an autoresuscitative behavior that, via large tidal volumes and altered intrathoracic pressure, can enhance coronary perfusion, carotid blood flow, and sympathetic activity, and thereby coordinate cardiac and respiratory functions. We tested the hypothesis that hypoxia-evoked gasps are amplified through a disinhibitory microcircuit within the inspiratory neuron chain and a distributed efference copy mechanism that generates coordinated gasp-like discharges concurrently in other circuits of the raphe-pontomedullary respiratory network. Data were obtained from 6 decerebrate, vagotomized, neuromuscularly-blocked, and artificially ventilated adult cats. Arterial blood pressure, phrenic nerve activity, end-tidal CO2, and other parameters were monitored. Hypoxia was produced by ventilation with a gas mixture of 5% O2 in nitrogen (N2). Neuron spike trains were recorded at multiple pontomedullary sites simultaneously and evaluated for firing rate modulations and short-time scale correlations indicative of functional connectivity. Experimental perturbations evoked reconfiguration of raphe-pontomedullary circuits during tachypnea, apneusis and augmented bursts, apnea, and gasping. The functional connectivity, altered firing rates, efference copy of gasp drive, and coordinated step increments in blood pressure reported here support a distributed brain stem network model for amplification and broadcasting of inspiratory drive during autoresuscitative gasping that begins with a reduction in inhibition by expiratory neurons and an initial loss of inspiratory drive during hypoxic apnea.
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3
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Palkovic B, Mustapic S, Saric I, Stuth EAE, Stucke AG, Zuperku EJ. Changes in pontine and preBötzinger/Bötzinger complex neuronal activity during remifentanil-induced respiratory depression in decerebrate dogs. Front Physiol 2023; 14:1156076. [PMID: 37362432 PMCID: PMC10285059 DOI: 10.3389/fphys.2023.1156076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
Introduction: In vivo studies using selective, localized opioid antagonist injections or localized opioid receptor deletion have identified that systemic opioids dose-dependently depress respiratory output through effects in multiple respiratory-related brainstem areas. Methods: With approval of the subcommittee on animal studies of the Zablocki VA Medical Center, experiments were performed in 53 decerebrate, vagotomized, mechanically ventilated dogs of either sex during isocapnic hyperoxia. We performed single neuron recordings in the Pontine Respiratory Group (PRG, n = 432) and preBötzinger/Bötzinger complex region (preBötC/BötC, n = 213) before and during intravenous remifentanil infusion (0.1-1 mcg/kg/min) and then until complete recovery of phrenic nerve activity. A generalized linear mixed model was used to determine changes in Fn with remifentanil and the statistical association between remifentanil-induced changes in Fn and changes in inspiratory and expiratory duration and peak phrenic activity. Analysis was controlled via random effects for animal, run, and neuron type. Results: Remifentanil decreased Fn in most neuron subtypes in the preBötC/BötC as well as in inspiratory (I), inspiratory-expiratory, expiratory (E) decrementing and non-respiratory modulated neurons in the PRG. The decrease in PRG inspiratory and non-respiratory modulated neuronal activity was associated with an increase in inspiratory duration. In the preBötC, the decrease in I-decrementing neuron activity was associated with an increase in expiratory and of E-decrementing activity with an increase in inspiratory duration. In contrast, decreased activity of I-augmenting neurons was associated with a decrease in inspiratory duration. Discussion: While statistical associations do not necessarily imply a causal relationship, our data suggest mechanisms for the opioid-induced increase in expiratory duration in the PRG and preBötC/BötC and how inspiratory failure at high opioid doses may result from a decrease in activity and decrease in slope of the pre-inspiratory ramp-like activity in preBötC/BötC pre-inspiratory neurons combined with a depression of preBötC/BötC I-augmenting neurons. Additional studies must clarify whether the observed changes in neuronal activity are due to direct neuronal inhibition or decreased excitatory inputs.
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Affiliation(s)
- Barbara Palkovic
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Faculty of Medicine, University of Osijek, Osijek, Croatia
| | - Sanda Mustapic
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- University Hospital Dubrava, Zagreb, Croatia
| | - Ivana Saric
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- University Hospital Split, Split, Croatia
| | - Eckehard A. E. Stuth
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Children’s Wisconsin, Milwaukee, WI, United States
| | - Astrid G. Stucke
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Children’s Wisconsin, Milwaukee, WI, United States
| | - Edward J. Zuperku
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Clement J Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States
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Pal A, Martinez F, Akey MA, Aysola RS, Henderson LA, Malhotra A, Macey PM. Breathing rate variability in obstructive sleep apnea during wakefulness. J Clin Sleep Med 2022; 18:825-833. [PMID: 34669569 PMCID: PMC8883075 DOI: 10.5664/jcsm.9728] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVES Obstructive sleep apnea (OSA) is defined by pauses in breathing during sleep, but daytime breathing dysregulation may also be present. Sleep may unmask breathing instability in OSA that is usually masked by behavioral influences during wakefulness. A breath-hold (BH) challenge has been used to demonstrate breathing instability. One measure of breathing stability is breathing rate variability (BRV). We aimed to assess BRV during rest and in response to BH in OSA. METHODS We studied 62 participants (31 with untreated OSA: respiratory event index [mean ± SD] 20 ± 15 events/h, 12 females, age 51 ± 14 years, body mass index [BMI] 32 ± 8 kg/m2; 31 controls: 17 females, age 47 ± 13 years; BMI 26 ± 4 kg/m2). Breathing movements were collected using a chest belt for 5 minutes of rest and during a BH protocol (60 seconds baseline, 30 seconds BH, 90 seconds recovery, 3 repeats). From the breathing movements, we calculated median breathing rate (BR) and interquartile BRV at rest. We calculated change in BRV during BH recovery from baseline. Group comparisons of OSA vs control were conducted using analysis of covariance with age, sex, and BMI as covariates. RESULTS We found 10% higher BRV in OSA vs controls (P < .05) during rest. In response to BH, BRV increased 7% in OSA vs 1% in controls (P < .001). Resting BR was not significantly different in OSA and controls, and sex and age did not have any significant interaction effects. BMI was associated with BR at rest (P < .05) and change in BRV with BH (P < .001), but no significant BMI-by-group interaction effect was observed. CONCLUSIONS The findings suggest breathing instability as reflected by BRV is high in OSA during wakefulness, both at rest and in response to a stimulus. Breathing instability together with high blood pressure variability in OSA may reflect a compromised cardiorespiratory consequence in OSA during wakefulness. CITATION Pal A, Martinez F, Akey MA, et al. Breathing rate variability in obstructive sleep apnea during wakefulness. J Clin Sleep Med. 2022;18(3):825-833.
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Affiliation(s)
- Amrita Pal
- UCLA School of Nursing, University of California, Los Angeles, Los Angeles, California
| | - Fernando Martinez
- UCLA School of Nursing, University of California, Los Angeles, Los Angeles, California
| | - Margaret A. Akey
- UCLA School of Nursing, University of California, Los Angeles, Los Angeles, California
| | - Ravi S. Aysola
- Division of Pulmonary and Critical Care, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, California
| | - Luke A. Henderson
- Brain and Mind Centre, School of Medical Sciences, University of Sydney, Sydney, Australia
| | - Atul Malhotra
- Department of Pulmonary Critical Care and Sleep Medicine, University of California, San Diego, San Diego, California
| | - Paul M. Macey
- UCLA School of Nursing, University of California, Los Angeles, Los Angeles, California,Address correspondence to: Paul M. Macey, PhD, UCLA School of Nursing, 700 Tiverton Avenue, Los Angeles, CA 90095-1702; Tel: (424) 234-3244;
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Smith JC. Respiratory rhythm and pattern generation: Brainstem cellular and circuit mechanisms. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:1-35. [PMID: 35965022 DOI: 10.1016/b978-0-323-91534-2.00004-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Breathing movements in mammals are driven by rhythmic neural activity automatically generated within spatially and functionally organized brainstem neural circuits comprising the respiratory central pattern generator (CPG). This chapter reviews up-to-date experimental information and theoretical studies of the cellular and circuit mechanisms of respiratory rhythm and pattern generation operating within critical components of this CPG in the lower brainstem. Over the past several decades, there have been substantial advances in delineating the spatial architecture of essential medullary regions and their regional cellular and circuit properties required to understand rhythm and pattern generation mechanisms. A fundamental concept is that the circuits in these regions have rhythm-generating capabilities at multiple cellular and circuit organization levels. The regional cellular properties, circuit organization, and control mechanisms allow flexible expression of neural activity patterns for a repertoire of respiratory behaviors under various physiologic conditions that are dictated by requirements for homeostatic regulation and behavioral integration. Many mechanistic insights have been provided by computational modeling studies driven by experimental results and have advanced understanding in the field. These conceptual and theoretical developments are discussed.
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Affiliation(s)
- Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
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6
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Shen TY, Poliacek I, Rose MJ, Musselwhite MN, Kotmanova Z, Martvon L, Pitts T, Davenport PW, Bolser DC. The role of neuronal excitation and inhibition in the pre-Bötzinger complex on the cough reflex in the cat. J Neurophysiol 2021; 127:267-278. [PMID: 34879205 PMCID: PMC8759968 DOI: 10.1152/jn.00108.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Brainstem respiratory neuronal network significantly contributes to cough motor pattern generation. Neuronal populations in the pre-Bötzinger complex (PreBötC) represent a substantial component for respiratory rhythmogenesis. We studied the role of PreBötC neuronal excitation and inhibition on mechanically induced tracheobronchial cough in 15 spontaneously breathing, pentobarbital anesthetized adult cats (35 mg/kg, iv initially). Neuronal excitation by unilateral microinjection of glutamate analog d,l-homocysteic acid resulted in mild reduction of cough abdominal electromyogram (EMG) amplitudes and very limited temporal changes of cough compared with effects on breathing (very high respiratory rate, high amplitude inspiratory bursts with a short inspiratory phase, and tonic inspiratory motor component). Mean arterial blood pressure temporarily decreased. Blocking glutamate-related neuronal excitation by bilateral microinjections of nonspecific glutamate receptor antagonist kynurenic acid reduced cough inspiratory and expiratory EMG amplitude and shortened most cough temporal characteristics similarly to breathing temporal characteristics. Respiratory rate decreased and blood pressure temporarily increased. Limiting active neuronal inhibition by unilateral and bilateral microinjections of GABAA receptor antagonist gabazine resulted in lower cough number, reduced expiratory cough efforts, and prolongation of cough temporal features and breathing phases (with lower respiratory rate). The PreBötC is important for cough motor pattern generation. Excitatory glutamatergic neurotransmission in the PreBötC is involved in control of cough intensity and patterning. GABAA receptor-related inhibition in the PreBötC strongly affects breathing and coughing phase durations in the same manner, as well as cough expiratory efforts. In conclusion, differences in effects on cough and breathing are consistent with separate control of these behaviors. NEW & NOTEWORTHY This study is the first to explore the role of the inspiratory rhythm and pattern generator, the pre-Bötzinger complex (PreBötC), in cough motor pattern formation. In the PreBötC, excitatory glutamatergic neurotransmission affects cough intensity and patterning but not rhythm, and GABAA receptor-related inhibition affects coughing and breathing phase durations similarly to each other. Our data show that the PreBötC is important for cough motor pattern generation, but cough rhythmogenesis appears to be controlled elsewhere.
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Affiliation(s)
- Tabitha Y Shen
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Ivan Poliacek
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States.,Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Martin, Slovak Republic
| | - Melanie J Rose
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Matthew Nicholas Musselwhite
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Zuzana Kotmanova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Martin, Slovak Republic
| | - Lukas Martvon
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Martin, Slovak Republic
| | - Teresa Pitts
- Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Paul W Davenport
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Donald C Bolser
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
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7
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Palkovic B, Marchenko V, Zuperku EJ, Stuth EAE, Stucke AG. Multi-Level Regulation of Opioid-Induced Respiratory Depression. Physiology (Bethesda) 2021; 35:391-404. [PMID: 33052772 DOI: 10.1152/physiol.00015.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Opioids depress minute ventilation primarily by reducing respiratory rate. This results from direct effects on the preBötzinger Complex as well as from depression of the Parabrachial/Kölliker-Fuse Complex, which provides excitatory drive to preBötzinger Complex neurons mediating respiratory phase-switch. Opioids also depress awake drive from the forebrain and chemodrive.
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Affiliation(s)
- Barbara Palkovic
- Medical College of Wisconsin, Milwaukee, Wisconsin.,Faculty of Medicine, University of Osijek, Osijek, Croatia
| | | | - Edward J Zuperku
- Medical College of Wisconsin, Milwaukee, Wisconsin.,Zablocki VA Medical Center, Milwaukee, Wisconsin
| | - Eckehard A E Stuth
- Medical College of Wisconsin, Milwaukee, Wisconsin.,Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - Astrid G Stucke
- Medical College of Wisconsin, Milwaukee, Wisconsin.,Children's Hospital of Wisconsin, Milwaukee, Wisconsin
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8
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Dose-dependent Respiratory Depression by Remifentanil in the Rabbit Parabrachial Nucleus/Kölliker-Fuse Complex and Pre-Bötzinger Complex. Anesthesiology 2021; 135:649-672. [PMID: 34352068 DOI: 10.1097/aln.0000000000003886] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Recent studies showed partial reversal of opioid-induced respiratory depression in the pre-Bötzinger complex and the parabrachial nucleus/Kölliker-Fuse complex. The hypothesis for this study was that opioid antagonism in the parabrachial nucleus/Kölliker-Fuse complex plus pre-Bötzinger complex completely reverses respiratory depression from clinically relevant opioid concentrations. METHODS Experiments were performed in 48 adult, artificially ventilated, decerebrate rabbits. The authors decreased baseline respiratory rate ~50% with intravenous, "analgesic" remifentanil infusion or produced apnea with remifentanil boluses and investigated the reversal with naloxone microinjections (1 mM, 700 nl) into the Kölliker-Fuse nucleus, parabrachial nucleus, and pre-Bötzinger complex. In another group of animals, naloxone was injected only into the pre-Bötzinger complex to determine whether prior parabrachial nucleus/Kölliker-Fuse complex injection impacted the naloxone effect. Last, the µ-opioid receptor agonist [d-Ala,2N-MePhe,4Gly-ol]-enkephalin (100 μM, 700 nl) was injected into the parabrachial nucleus/Kölliker-Fuse complex. The data are presented as medians (25 to 75%). RESULTS Remifentanil infusion reduced the respiratory rate from 36 (31 to 40) to 16 (15 to 21) breaths/min. Naloxone microinjections into the bilateral Kölliker-Fuse nucleus, parabrachial nucleus, and pre-Bötzinger complex increased the rate to 17 (16 to 22, n = 19, P = 0.005), 23 (19 to 29, n = 19, P < 0.001), and 25 (22 to 28) breaths/min (n = 11, P < 0.001), respectively. Naloxone injection into the parabrachial nucleus/Kölliker-Fuse complex prevented apnea in 12 of 17 animals, increasing the respiratory rate to 10 (0 to 12) breaths/min (P < 0.001); subsequent pre-Bötzinger complex injection prevented apnea in all animals (13 [10 to 19] breaths/min, n = 12, P = 0.002). Naloxone injection into the pre-Bötzinger complex alone increased the respiratory rate to 21 (15 to 26) breaths/min during analgesic concentrations (n = 10, P = 0.008) but not during apnea (0 [0 to 0] breaths/min, n = 9, P = 0.500). [d-Ala,2N-MePhe,4Gly-ol]-enkephalin injection into the parabrachial nucleus/Kölliker-Fuse complex decreased respiratory rate to 3 (2 to 6) breaths/min. CONCLUSIONS Opioid reversal in the parabrachial nucleus/Kölliker-Fuse complex plus pre-Bötzinger complex only partially reversed respiratory depression from analgesic and even less from "apneic" opioid doses. The lack of recovery pointed to opioid-induced depression of respiratory drive that determines the activity of these areas. EDITOR’S PERSPECTIVE
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9
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Packiasabapathy S, Zhang X, Ding L, Aruldhas BW, Pawale D, Sadhasivam S. Quantitative Pupillometry as a Predictor of Pediatric Postoperative Opioid-Induced Respiratory Depression. Anesth Analg 2021; 133:991-999. [PMID: 34029273 DOI: 10.1213/ane.0000000000005579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Safe postoperative pain relief with opioids is an unmet critical medical need in children. There is a lack of objective, noninvasive bedside tool to assess central nervous system (CNS) effects of intraoperative opioids. Proactive identification of children at risk for postoperative respiratory depression (RD) will help tailor analgesic therapy and significantly improve the safety of opioids in children. Quantitative pupillometry (QP) is a noninvasive, objective, and real-time tool for monitoring CNS effect-time relationship of opioids. This exploratory study aimed to determine the association of QP measures with postoperative RD, as well as to identify the best intraoperative QP measures predictive of postoperative RD in children. METHODS After approval from the institutional review board and informed parental consent, in this prospective, observational study of 220 children undergoing tonsillectomy, QP measures were collected at 5 time points: awake preoperative baseline before anesthesia induction (at the time of enrollment [T1]), immediately after anesthesia induction before morphine administration (T2), 3 minutes after intraoperative morphine administration (T3), at the end of surgery (T4), and postoperatively when awake in postanesthesia recovery unit (PACU) (T5). Intraoperative use of opioid and incidence of postoperative RD were collected. Analyses were aimed at exploring correlations of QP measures with the incidence of RD and, if found significant, to develop a predictive model for postoperative RD. RESULTS Perioperative QP measures of percentage pupil constriction (CONQ, P = .027), minimum pupillary diameter (MIN, P = .027), and maximum pupillary diameter (MAX, P = .034) differed significantly among children with and without postoperative RD. A predictive model including the minimum pupillary diameter 3 minutes after morphine administration (MIN3), minimum pupillary diameter normalized to baseline (MIN31), and percentage pupillary constriction after surgery (T4) standardized to baseline (T1) (CONQ41), along with the weight-based morphine dose performed the best to predict postoperative RD in children (area under the curve [AUC], 0.76). CONCLUSIONS A model based on pre- and intraoperative pupillometry measures including CONQ, MIN, along with weight-based morphine dose-predicted postoperative RD in our cohort of children undergoing tonsillectomy. More studies with a larger sample size are required to validate this finding.
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Affiliation(s)
- Senthil Packiasabapathy
- From the Department of Anesthesia, Indiana University School of Medicine, Indianapolis, Indiana
| | | | - Lili Ding
- Division of Human Genetics.,Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Blessed W Aruldhas
- From the Department of Anesthesia, Indiana University School of Medicine, Indianapolis, Indiana.,Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.,Department of Pharmacology & Clinical Pharmacology, Christian Medical College, Vellore, India
| | - Dhanashri Pawale
- From the Department of Anesthesia, Indiana University School of Medicine, Indianapolis, Indiana
| | - Senthilkumar Sadhasivam
- From the Department of Anesthesia, Indiana University School of Medicine, Indianapolis, Indiana
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10
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Ramirez JM, Burgraff NJ, Wei AD, Baertsch NA, Varga AG, Baghdoyan HA, Lydic R, Morris KF, Bolser DC, Levitt ES. Neuronal mechanisms underlying opioid-induced respiratory depression: our current understanding. J Neurophysiol 2021; 125:1899-1919. [PMID: 33826874 DOI: 10.1152/jn.00017.2021] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Opioid-induced respiratory depression (OIRD) represents the primary cause of death associated with therapeutic and recreational opioid use. Within the United States, the rate of death from opioid abuse since the early 1990s has grown disproportionally, prompting the classification as a nationwide "epidemic." Since this time, we have begun to unravel many fundamental cellular and systems-level mechanisms associated with opioid-related death. However, factors such as individual vulnerability, neuromodulatory compensation, and redundancy of opioid effects across central and peripheral nervous systems have created a barrier to a concise, integrative view of OIRD. Within this review, we bring together multiple perspectives in the field of OIRD to create an overarching viewpoint of what we know, and where we view this essential topic of research going forward into the future.
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Affiliation(s)
- Jan-Marino Ramirez
- Department of Neurological Surgery, University of Washington, Seattle, Washington.,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Nicholas J Burgraff
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Aguan D Wei
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Nathan A Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Adrienn G Varga
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida.,Center for Respiratory Research and Rehabilitation, Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Helen A Baghdoyan
- Department of Psychology, University of Tennessee, Knoxville, Tennessee.,Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Ralph Lydic
- Department of Psychology, University of Tennessee, Knoxville, Tennessee.,Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Erica S Levitt
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida.,Center for Respiratory Research and Rehabilitation, Department of Physical Therapy, University of Florida, Gainesville, Florida
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11
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Segers LS, Nuding SC, Ott MM, O'Connor R, Morris KF, Lindsey BG. Blood pressure drives multispectral tuning of inspiration via a linked-loop neural network. J Neurophysiol 2020; 124:1676-1697. [PMID: 32965158 DOI: 10.1152/jn.00442.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The respiratory motor pattern is coordinated with cardiovascular system regulation. Inspiratory drive and respiratory phase durations are tuned by blood pressure and baroreceptor reflexes. We hypothesized that perturbations of systemic arterial blood pressure modulate inspiratory drive through a raphe-pontomedullary network. In 15 adult decerebrate vagotomized neuromuscular-blocked cats, we used multielectrode arrays to record the activities of 704 neurons within the medullary ventral respiratory column, pons, and raphe areas during baroreceptor-evoked perturbations of breathing, as measured by altered peak activity in integrated efferent phrenic nerve activity and changes in respiratory phase durations. Blood pressure was transiently (30 s) elevated or reduced by inflations of an embolectomy catheter in the descending aorta or inferior vena cava. S-transform time-frequency representations were calculated for multiunit phrenic nerve activity and some spike trains to identify changes in rhythmic activity during perturbations. Altered firing rates in response to either or both conditions were detected for 474 of 704 tested cells. Spike trains of 17,805 neuron pairs were evaluated for short-time scale correlational signatures indicative of functional connectivity with standard cross-correlation analysis, supplemented with gravitational clustering; ∼70% of tested (498 of 704) and responding neurons (333 of 474) were involved in a functional correlation with at least one other cell. Changes in high-frequency oscillations in the spiking of inspiratory neurons and the evocation or resetting of slow quasi-periodic fluctuations in the respiratory motor pattern associated with oscillations of arterial pressure were observed. The results support a linked-loop pontomedullary network architecture for multispectral tuning of inspiration.NEW & NOTEWORTHY The brain network that supports cardiorespiratory coupling remains poorly understood. Using multielectrode arrays, we tested the hypothesis that blood pressure and baroreceptor reflexes "tune" the breathing motor pattern via a raphe-pontomedullary network. Neuron responses to changes in arterial pressure and identified functional connectivity, together with altered high frequency and slow Lundberg B-wave oscillations, support a model with linked recurrent inhibitory loops that stabilize the respiratory network and provide a path for transmission of baroreceptor signals.
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Affiliation(s)
- Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Mackenzie M Ott
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Russell O'Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
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12
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Volume feedback during cough in anesthetized cats, effects of occlusions and modulation summary. Respir Physiol Neurobiol 2020; 283:103547. [PMID: 32942050 DOI: 10.1016/j.resp.2020.103547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/28/2020] [Accepted: 09/10/2020] [Indexed: 11/23/2022]
Abstract
The study investigates the effects of 6 occlusion conditions on the mechanically induced cough reflex in 15 anesthetized (pentobarbital) spontaneously breathing cats (14♂, 1♀). Esophageal pressure and integrated EMG activities of inspiratory (I) diaphragm and expiratory (E) abdominal muscles were recorded and analyzed. Occlusions: inspiratory (Io), continual I (cIo), during I and active E (I+Eo) cough phase, during I and then E phase with short releasing of airflow before each phase (I-Eo), and E occlusion (Eo) had little influence on cough number. Only continual E occlusion (cEo) reduced the number of coughs by 19 % (to 81 %, p < 0.05). Cough I esophageal pressure reached higher amplitudes under all conditions, but only Eo caused increased I diaphragm motor drive (p < 0.05). Cough E efforts (abdominal motor drive and E amplitudes of esophageal pressure) increased during Eo, decreased during I+Eo (p < 0.05), and did not change significantly under other conditions (p > 0.05). All I blocks resulted in prolonged I cough characteristics (p < 0.05) mainly cough I phase (incrementing part of the diaphragm activity). Shorter I phase occurred with cEo (p < 0.05). Cough cycle time and active E phase (from the I maximum to the end of cough E motor drive) prolonged (p < 0.05) during all occlusions (E phase duration statistically non-significantly for I+Eo). Airflow block during cough (occlusions) results in secondary changes in the cough response due to markedly altered function of cough central pattern generator and cough motor pattern produced. Cough compensatory effects during airflow resistances are more favorable compared to occlusions. Volume feedback represents significant factor of cough modulation under various pathological obstruction and/or restriction conditions of the respiratory system.
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13
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Spikes and Nets (S&N): A New Fast, Parallel Computing, Point Process Software for Multineuronal Discharge and Connectivity Analysis. Neural Process Lett 2020. [DOI: 10.1007/s11063-020-10242-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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14
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Dhingra RR, Dick TE, Furuya WI, Galán RF, Dutschmann M. Volumetric mapping of the functional neuroanatomy of the respiratory network in the perfused brainstem preparation of rats. J Physiol 2020; 598:2061-2079. [PMID: 32100293 DOI: 10.1113/jp279605] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 02/05/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The functional neuroanatomy of the mammalian respiratory network is far from being understood since experimental tools that measure neural activity across this brainstem-wide circuit are lacking. Here, we use silicon multi-electrode arrays to record respiratory local field potentials (rLFPs) from 196-364 electrode sites within 8-10 mm3 of brainstem tissue in single arterially perfused brainstem preparations with respect to the ongoing respiratory motor pattern of inspiration (I), post-inspiration (PI) and late-expiration (E2). rLFPs peaked specifically at the three respiratory phase transitions, E2-I, I-PI and PI-E2. We show, for the first time, that only the I-PI transition engages a brainstem-wide network, and that rLFPs during the PI-E2 transition identify a hitherto unknown role for the dorsal respiratory group. Volumetric mapping of pontomedullary rLFPs in single preparations could become a reliable tool for assessing the functional neuroanatomy of the respiratory network in health and disease. ABSTRACT While it is widely accepted that inspiratory rhythm generation depends on the pre-Bötzinger complex, the functional neuroanatomy of the neural circuits that generate expiration is debated. We hypothesized that the compartmental organization of the brainstem respiratory network is sufficient to generate macroscopic local field potentials (LFPs), and if so, respiratory (r) LFPs could be used to map the functional neuroanatomy of the respiratory network. We developed an approach using silicon multi-electrode arrays to record spontaneous LFPs from hundreds of electrode sites in a volume of brainstem tissue while monitoring the respiratory motor pattern on phrenic and vagal nerves in the perfused brainstem preparation. Our results revealed the expression of rLFPs across the pontomedullary brainstem. rLFPs occurred specifically at the three transitions between respiratory phases: (1) from late expiration (E2) to inspiration (I), (2) from I to post-inspiration (PI), and (3) from PI to E2. Thus, respiratory network activity was maximal at respiratory phase transitions. Spatially, the E2-I, and PI-E2 transitions were anatomically localized to the ventral and dorsal respiratory groups, respectively. In contrast, our data show, for the first time, that the generation of controlled expiration during the post-inspiratory phase engages a distributed neuronal population within ventral, dorsal and pontine network compartments. A group-wise independent component analysis demonstrated that all preparations exhibited rLFPs with a similar temporal structure and thus share a similar functional neuroanatomy. Thus, volumetric mapping of rLFPs could allow for the physiological assessment of global respiratory network organization in health and disease.
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Affiliation(s)
- Rishi R Dhingra
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, Melbourne, Australia
| | - Thomas E Dick
- Division of Pulmonary, Critical Care & Sleep, Department of Medicine, Case Western Reserve University, Cleveland, USA
| | - Werner I Furuya
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, Melbourne, Australia
| | - Roberto F Galán
- Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, USA
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, Melbourne, Australia
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15
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Endogenous glutamatergic inputs to the Parabrachial Nucleus/Kölliker-Fuse Complex determine respiratory rate. Respir Physiol Neurobiol 2020; 277:103401. [PMID: 32036030 DOI: 10.1016/j.resp.2020.103401] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/06/2020] [Accepted: 01/28/2020] [Indexed: 01/10/2023]
Abstract
The Kölliker-Fuse Nucleus (KF) has been widely investigated for its contribution to "inspiratory off-switch" while more recent studies showed that activation of the Parabrachial Nucleus (PBN) shortened expiratory duration. This study used an adult, in vivo, decerebrate rabbit model to delineate the contribution of each site to inspiratory and expiratory duration through sequential block of glutamatergic excitation with the receptor antagonists 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX) and d(-)-2-amino-5-phosphonopentanoic acid (AP5). Glutamatergic disfacilitation caused large increases in inspiratory and expiratory duration and minor decrease in peak phrenic activity (PPA). Hypoxia only partially reversed respiratory rate depression but PPA was increased to >200 % of control. The contribution of PBN activity to inspiratory and expiratory duration was equal while block of the KF affected inspiratory duration more than expiratory. We conclude that in the in vivo preparation respiratory rate greatly depends on PBN/KF activity, which contributes to the "inspiratory on- "and "off-switch", but is of minor importance for the magnitude of phrenic motor output.
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16
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Streeter KA, Sunshine MD, Patel SR, Gonzalez-Rothi EJ, Reier PJ, Baekey DM, Fuller DD. Mid-cervical interneuron networks following high cervical spinal cord injury. Respir Physiol Neurobiol 2019; 271:103305. [PMID: 31553921 DOI: 10.1016/j.resp.2019.103305] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/22/2019] [Accepted: 09/20/2019] [Indexed: 12/15/2022]
Abstract
Spinal interneuron (IN) networks can facilitate respiratory motor recovery after spinal cord injury (SCI). We hypothesized that excitatory synaptic connectivity between INs located immediately caudal to unilateral cervical SCI would be most prevalent in a contra- to ipsilateral direction. Adult rats were studied following chronic C2 spinal cord hemisection (C2Hx) injury. Rats were anesthetized and ventilated and a multi-electrode array was used to simultaneously record INs on both sides of the C4-5 spinal cord. The temporal firing relationship between IN pairs was evaluated using cross-correlation with directionality of synaptic connections inferred based on electrode location. During baseline recordings, the majority of detectable excitatory IN connections occurred in a contra- to- ipsilateral direction. However, acute respiratory stimulation with hypoxia abolished this directionality, while simultaneously increasing the detectable inhibitory connections within the ipsilateral cord. We conclude that propriospinal networks caudal to SCI can display a contralateral-to-ipsilateral directionality of synaptic connections and that these connections are modulated by acute exposure to hypoxia.
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Affiliation(s)
- K A Streeter
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, United States; McKnight Brain Institute, University of Florida, Gainesville, FL 32601, United States; Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL 32610, United States
| | - M D Sunshine
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, United States; Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL 32610, United States
| | - S R Patel
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, United States
| | - E J Gonzalez-Rothi
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, United States; McKnight Brain Institute, University of Florida, Gainesville, FL 32601, United States; Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL 32610, United States
| | - P J Reier
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, United States; McKnight Brain Institute, University of Florida, Gainesville, FL 32601, United States
| | - D M Baekey
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, United States; Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL 32610, United States
| | - D D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, United States; McKnight Brain Institute, University of Florida, Gainesville, FL 32601, United States; Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL 32610, United States.
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17
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Lindsey BG, Nuding SC, Segers LS, Morris KF. Carotid Bodies and the Integrated Cardiorespiratory Response to Hypoxia. Physiology (Bethesda) 2019; 33:281-297. [PMID: 29897299 DOI: 10.1152/physiol.00014.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Advances in our understanding of brain mechanisms for the hypoxic ventilatory response, coordinated changes in blood pressure, and the long-term consequences of chronic intermittent hypoxia as in sleep apnea, such as hypertension and heart failure, are giving impetus to the search for therapies to "erase" dysfunctional memories distributed in the carotid bodies and central nervous system. We review current network models, open questions, sex differences, and implications for translational research.
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Affiliation(s)
- Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
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18
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Noto T, Zhou G, Schuele S, Templer J, Zelano C. Automated analysis of breathing waveforms using BreathMetrics: a respiratory signal processing toolbox. Chem Senses 2018; 43:583-597. [PMID: 29985980 PMCID: PMC6150778 DOI: 10.1093/chemse/bjy045] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Nasal inhalation is the basis of olfactory perception and drives neural activity in olfactory and limbic brain regions. Therefore, our ability to investigate the neural underpinnings of olfaction and respiration can only be as good as our ability to characterize features of respiratory behavior. However, recordings of natural breathing are inherently nonstationary, nonsinusoidal, and idiosyncratic making feature extraction difficult to automate. The absence of a freely available computational tool for characterizing respiratory behavior is a hindrance to many facets of olfactory and respiratory neuroscience. To solve this problem, we developed BreathMetrics, an open-source tool that automatically extracts the full set of features embedded in human nasal airflow recordings. Here, we rigorously validate BreathMetrics' feature estimation accuracy on multiple nasal airflow datasets, intracranial electrophysiological recordings of human olfactory cortex, and computational simulations of breathing signals. We hope this tool will allow researchers to ask new questions about how respiration relates to body, brain, and behavior.
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Affiliation(s)
- Torben Noto
- Department of Neurology, Northwestern University Feinberg School of Medicine, Ward, Chicago, IL, USA
| | - Guangyu Zhou
- Department of Neurology, Northwestern University Feinberg School of Medicine, Ward, Chicago, IL, USA
| | - Stephan Schuele
- Department of Neurology, Northwestern University Feinberg School of Medicine, Ward, Chicago, IL, USA
| | - Jessica Templer
- Department of Neurology, Northwestern University Feinberg School of Medicine, Ward, Chicago, IL, USA
| | - Christina Zelano
- Department of Neurology, Northwestern University Feinberg School of Medicine, Ward, Chicago, IL, USA
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19
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Zuperku EJ, Stucke AG, Krolikowski JG, Tomlinson J, Hopp FA, Stuth EA. Inputs to medullary respiratory neurons from a pontine subregion that controls breathing frequency. Respir Physiol Neurobiol 2018; 265:127-140. [PMID: 29964165 DOI: 10.1016/j.resp.2018.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/10/2018] [Accepted: 06/04/2018] [Indexed: 11/30/2022]
Abstract
Neurons in a subregion of the medial parabrachial (PB) complex control expiratory duration (TE) and the inspiratory on-switch. To better understanding the underlying mechanisms, this study aimed to determine the types of medullary neurons in the rhythmogenic preBötzinger/Bötzinger Complex (preBötC/BötC) and adjacent areas that receive synaptic inputs from the PB subregion and whether these inputs are excitatory or inhibitory in nature. Highly localized electrical stimuli in the PB subregion combined with multi-electrode recordings from respiratory neurons and phrenic nerve activities were used to generate stimulus-to-spike event histograms to detect correlations in decerebrate, vagotomized dogs during isocapnic hyperoxia. Short-time scale correlations were found in 237/442 or ∼54% of the ventral respiratory column (VRC) neurons. Inhibition of E-neurons was ∼2.5X greater than for I-neurons, while Pre-I and I-neurons were excited. These findings indicate that the control of TE and the inspiratory on-switch by the PB subregion are mediated by a marked inhibition of BötC E-neurons combined with an excitation of I-neurons, especially pre-I neurons.
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Affiliation(s)
- Edward J Zuperku
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.
| | - Astrid G Stucke
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Pediatric Anesthesia, Children's Hospital of Wisconsin, Milwaukee, WI, United States
| | - John G Krolikowski
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jack Tomlinson
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Francis A Hopp
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States
| | - Eckehard A Stuth
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Pediatric Anesthesia, Children's Hospital of Wisconsin, Milwaukee, WI, United States
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20
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Peña-Ortega F. Neural Network Reconfigurations: Changes of the Respiratory Network by Hypoxia as an Example. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1015:217-237. [PMID: 29080029 DOI: 10.1007/978-3-319-62817-2_12] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Neural networks, including the respiratory network, can undergo a reconfiguration process by just changing the number, the connectivity or the activity of their elements. Those elements can be either brain regions or neurons, which constitute the building blocks of macrocircuits and microcircuits, respectively. The reconfiguration processes can also involve changes in the number of connections and/or the strength between the elements of the network. These changes allow neural networks to acquire different topologies to perform a variety of functions or change their responses as a consequence of physiological or pathological conditions. Thus, neural networks are not hardwired entities, but they constitute flexible circuits that can be constantly reconfigured in response to a variety of stimuli. Here, we are going to review several examples of these processes with special emphasis on the reconfiguration of the respiratory rhythm generator in response to different patterns of hypoxia, which can lead to changes in respiratory patterns or lasting changes in frequency and/or amplitude.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, UNAM-Campus Juriquilla, Boulevard Juriquilla 3001, Querétaro, 76230, Mexico.
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21
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Morris KF, Nuding SC, Segers LS, Iceman KE, O'Connor R, Dean JB, Ott MM, Alencar PA, Shuman D, Horton KK, Taylor-Clark TE, Bolser DC, Lindsey BG. Carotid chemoreceptors tune breathing via multipath routing: reticular chain and loop operations supported by parallel spike train correlations. J Neurophysiol 2017; 119:700-722. [PMID: 29046425 DOI: 10.1152/jn.00630.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We tested the hypothesis that carotid chemoreceptors tune breathing through parallel circuit paths that target distinct elements of an inspiratory neuron chain in the ventral respiratory column (VRC). Microelectrode arrays were used to monitor neuronal spike trains simultaneously in the VRC, peri-nucleus tractus solitarius (p-NTS)-medial medulla, the dorsal parafacial region of the lateral tegmental field (FTL-pF), and medullary raphe nuclei together with phrenic nerve activity during selective stimulation of carotid chemoreceptors or transient hypoxia in 19 decerebrate, neuromuscularly blocked, and artificially ventilated cats. Of 994 neurons tested, 56% had a significant change in firing rate. A total of 33,422 cell pairs were evaluated for signs of functional interaction; 63% of chemoresponsive neurons were elements of at least one pair with correlational signatures indicative of paucisynaptic relationships. We detected evidence for postinspiratory neuron inhibition of rostral VRC I-Driver (pre-Bötzinger) neurons, an interaction predicted to modulate breathing frequency, and for reciprocal excitation between chemoresponsive p-NTS neurons and more downstream VRC inspiratory neurons for control of breathing depth. Chemoresponsive pericolumnar tonic expiratory neurons, proposed to amplify inspiratory drive by disinhibition, were correlationally linked to afferent and efferent "chains" of chemoresponsive neurons extending to all monitored regions. The chains included coordinated clusters of chemoresponsive FTL-pF neurons with functional links to widespread medullary sites involved in the control of breathing. The results support long-standing concepts on brain stem network architecture and a circuit model for peripheral chemoreceptor modulation of breathing with multiple circuit loops and chains tuned by tegmental field neurons with quasi-periodic discharge patterns. NEW & NOTEWORTHY We tested the long-standing hypothesis that carotid chemoreceptors tune the frequency and depth of breathing through parallel circuit operations targeting the ventral respiratory column. Responses to stimulation of the chemoreceptors and identified functional connectivity support differential tuning of inspiratory neuron burst duration and firing rate and a model of brain stem network architecture incorporating tonic expiratory "hub" neurons regulated by convergent neuronal chains and loops through rostral lateral tegmental field neurons with quasi-periodic discharge patterns.
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Affiliation(s)
- Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Kimberly E Iceman
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Russell O'Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Jay B Dean
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Mackenzie M Ott
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Pierina A Alencar
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Dale Shuman
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Kofi-Kermit Horton
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Thomas E Taylor-Clark
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida , Gainesville, Florida
| | - Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
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22
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BuSha BF, Banis G. A stochastic and integrative model of breathing. Respir Physiol Neurobiol 2017; 237:51-56. [DOI: 10.1016/j.resp.2016.12.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 12/21/2016] [Accepted: 12/28/2016] [Indexed: 12/17/2022]
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23
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Nuding SC, Segers LS, Iceman KE, O'Connor R, Dean JB, Bolser DC, Baekey DM, Dick TE, Shannon R, Morris KF, Lindsey BG. Functional connectivity in raphé-pontomedullary circuits supports active suppression of breathing during hypocapnic apnea. J Neurophysiol 2015; 114:2162-86. [PMID: 26203111 PMCID: PMC4600964 DOI: 10.1152/jn.00608.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 07/18/2015] [Indexed: 01/17/2023] Open
Abstract
Hyperventilation is a common feature of disordered breathing. Apnea ensues if CO2 drive is sufficiently reduced. We tested the hypothesis that medullary raphé, ventral respiratory column (VRC), and pontine neurons have functional connectivity and persistent or evoked activities appropriate for roles in the suppression of drive and rhythm during hyperventilation and apnea. Phrenic nerve activity, arterial blood pressure, end-tidal CO2, and other parameters were monitored in 10 decerebrate, vagotomized, neuromuscularly-blocked, and artificially ventilated cats. Multielectrode arrays recorded spiking activity of 649 neurons. Loss and return of rhythmic activity during passive hyperventilation to apnea were identified with the S-transform. Diverse fluctuating activity patterns were recorded in the raphé-pontomedullary respiratory network during the transition to hypocapnic apnea. The firing rates of 160 neurons increased during apnea; the rates of 241 others decreased or stopped. VRC inspiratory neurons were usually the last to cease firing or lose rhythmic activity during the transition to apnea. Mayer wave-related oscillations (0.04-0.1 Hz) in firing rate were also disrupted during apnea. Four-hundred neurons (62%) were elements of pairs with at least one hyperventilation-responsive neuron and a correlational signature of interaction identified by cross-correlation or gravitational clustering. Our results support a model with distinct groups of chemoresponsive raphé neurons contributing to hypocapnic apnea through parallel processes that incorporate disfacilitation and active inhibition of inspiratory motor drive by expiratory neurons. During apnea, carotid chemoreceptors can evoke rhythm reemergence and an inspiratory shift in the balance of reciprocal inhibition via suppression of ongoing tonic expiratory neuron activity.
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Affiliation(s)
- Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Kimberly E Iceman
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Russell O'Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Jay B Dean
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and
| | - David M Baekey
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and
| | - Thomas E Dick
- Departments of Medicine and Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Roger Shannon
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida;
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Feldman JL, Kam K. Facing the challenge of mammalian neural microcircuits: taking a few breaths may help. J Physiol 2015; 593:3-23. [PMID: 25556783 DOI: 10.1113/jphysiol.2014.277632] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 11/01/2014] [Indexed: 12/27/2022] Open
Abstract
Breathing in mammals is a seemingly straightforward behaviour controlled by the brain. A brainstem nucleus called the preBötzinger Complex sits at the core of the neural circuit generating respiratory rhythm. Despite the discovery of this microcircuit almost 25 years ago, the mechanisms controlling breathing remain elusive. Given the apparent simplicity and well-defined nature of regulatory breathing behaviour, the identification of much of the circuitry, and the ability to study breathing in vitro as well as in vivo, many neuroscientists and physiologists are surprised that respiratory rhythm generation is still not well understood. Our view is that conventional rhythmogenic mechanisms involving pacemakers, inhibition or bursting are problematic and that simplifying assumptions commonly made for many vertebrate neural circuits ignore consequential detail. We propose that novel emergent mechanisms govern the generation of respiratory rhythm. That a mammalian function as basic as rhythm generation arises from complex and dynamic molecular, synaptic and neuronal interactions within a diverse neural microcircuit highlights the challenges in understanding neural control of mammalian behaviours, many (considerably) more elaborate than breathing. We suggest that the neural circuit controlling breathing is inimitably tractable and may inspire general strategies for elucidating other neural microcircuits.
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Affiliation(s)
- Jack L Feldman
- Systems Neurobiology Laboratory, Department of Neurobiology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, USA
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25
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Opioid-induced Respiratory Depression Is Only Partially Mediated by the preBötzinger Complex in Young and Adult Rabbits In Vivo. Anesthesiology 2015; 122:1288-98. [PMID: 25751234 DOI: 10.1097/aln.0000000000000628] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The preBötzinger Complex (preBC) plays an important role in respiratory rhythm generation. This study was designed to determine whether the preBC mediated opioid-induced respiratory rate depression at clinically relevant opioid concentrations in vivo and whether this role was age dependent. METHODS Studies were performed in 22 young and 32 adult New Zealand White rabbits. Animals were anesthetized, mechanically ventilated, and decerebrated. The preBC was identified by the tachypneic response to injection of D,L-homocysteic acid. (1) The μ-opioid receptor agonist [D-Ala2,N-Me-Phe4,Gly-ol]-enkephalin (DAMGO, 100 μM) was microinjected into the bilateral preBC and reversed with naloxone (1 mM) injection into the preBC. (2) Respiratory depression was achieved with intravenous remifentanil (0.08 to 0.5 μg kg(-1) min(-1)). Naloxone (1 mM) was microinjected into the preBC in an attempt to reverse the respiratory depression. RESULTS (1) DAMGO injection depressed respiratory rate by 6 ± 8 breaths/min in young and adult rabbits (mean ± SD, P < 0.001). DAMGO shortened the inspiratory and lengthened the expiratory fraction of the respiratory cycle by 0.24 ± 0.2 in adult and young animals (P < 0.001). (2) During intravenous remifentanil infusion, local injection of naloxone into the preBC partially reversed the decrease in inspiratory fraction/increase in expiratory fraction in young and adult animals (0.14 ± 0.14, P < 0.001), but not the depression of respiratory rate (P = 0.19). PreBC injections did not affect respiratory drive. In adult rabbits, the contribution of non-preBC inputs to expiratory phase duration was larger than preBC inputs (3.5 [-5.2 to 1.1], median [25 to 75%], P = 0.04). CONCLUSIONS Systemic opioid effects on respiratory phase timing can be partially reversed in the preBC without reversing the depression of respiratory rate.
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NMDA and GABA receptors as potential targets in cough hypersensitivity syndrome. Curr Opin Pharmacol 2015; 22:29-36. [DOI: 10.1016/j.coph.2015.03.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/02/2015] [Accepted: 03/02/2015] [Indexed: 12/21/2022]
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Zuperku EJ, Prkic I, Stucke AG, Miller JR, Hopp FA, Stuth EA. Automatic classification of canine PRG neuronal discharge patterns using K-means clustering. Respir Physiol Neurobiol 2014; 207:28-39. [PMID: 25511381 DOI: 10.1016/j.resp.2014.11.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/06/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Respiratory-related neurons in the parabrachial-Kölliker-Fuse (PB-KF) region of the pons play a key role in the control of breathing. The neuronal activities of these pontine respiratory group (PRG) neurons exhibit a variety of inspiratory (I), expiratory (E), phase spanning and non-respiratory related (NRM) discharge patterns. Due to the variety of patterns, it can be difficult to classify them into distinct subgroups according to their discharge contours. This report presents a method that automatically classifies neurons according to their discharge patterns and derives an average subgroup contour of each class. It is based on the K-means clustering technique and it is implemented via SigmaPlot User-Defined transform scripts. The discharge patterns of 135 canine PRG neurons were classified into seven distinct subgroups. Additional methods for choosing the optimal number of clusters are described. Analysis of the results suggests that the K-means clustering method offers a robust objective means of both automatically categorizing neuron patterns and establishing the underlying archetypical contours of subtypes based on the discharge patterns of group of neurons.
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Affiliation(s)
- Edward J Zuperku
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, USA; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Ivana Prkic
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, USA; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Astrid G Stucke
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, USA; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA; Children's Hospital of Wisconsin, Pediatric Anesthesia, Milwaukee, WI, USA
| | - Justin R Miller
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, USA; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Francis A Hopp
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, USA
| | - Eckehard A Stuth
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, USA; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA; Children's Hospital of Wisconsin, Pediatric Anesthesia, Milwaukee, WI, USA
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Johnson SM, Hedrick MS, Krause BM, Nilles JP, Chapman MA. Respiratory neuron characterization reveals intrinsic bursting properties in isolated adult turtle brainstems (Trachemys scripta). Respir Physiol Neurobiol 2014; 224:52-61. [PMID: 25462012 DOI: 10.1016/j.resp.2014.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/03/2014] [Accepted: 11/06/2014] [Indexed: 11/25/2022]
Abstract
It is not known whether respiratory neurons with intrinsic bursting properties exist within ectothermic vertebrate respiratory control systems. Thus, isolated adult turtle brainstems spontaneously producing respiratory motor output were used to identify and classify respiratory neurons based on their firing pattern relative to hypoglossal (XII) nerve activity. Most respiratory neurons (183/212) had peak activity during the expiratory phase, while inspiratory, post-inspiratory, and novel pre-expiratory neurons were less common. During synaptic blockade conditions, ∼10% of respiratory neurons fired bursts of action potentials, with post-inspiratory cells (6/9) having the highest percentage of intrinsic burst properties. Most intrinsically bursting respiratory neurons were clustered at the level of the vagus (X) nerve root. Synaptic inhibition blockade caused seizure-like activity throughout the turtle brainstem, which shows that the turtle respiratory control system is not transformed into a network driven by intrinsically bursting respiratory neurons. We hypothesize that intrinsically bursting respiratory neurons are evolutionarily conserved and represent a potential rhythmogenic mechanism contributing to respiration in adult turtles.
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Affiliation(s)
- Stephen M Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, United States.
| | - Michael S Hedrick
- Department of Biological Sciences, California State University, East Bay, Hayward, CA 94542, United States
| | - Bryan M Krause
- Neuroscience Training Program, University of Wisconsin, Madison, WI 53706, United States
| | - Jacob P Nilles
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, United States
| | - Mark A Chapman
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, United States
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Segers LS, Nuding SC, Ott MM, Dean JB, Bolser DC, O'Connor R, Morris KF, Lindsey BG. Peripheral chemoreceptors tune inspiratory drive via tonic expiratory neuron hubs in the medullary ventral respiratory column network. J Neurophysiol 2014; 113:352-68. [PMID: 25343784 DOI: 10.1152/jn.00542.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Models of brain stem ventral respiratory column (VRC) circuits typically emphasize populations of neurons, each active during a particular phase of the respiratory cycle. We have proposed that "tonic" pericolumnar expiratory (t-E) neurons tune breathing during baroreceptor-evoked reductions and central chemoreceptor-evoked enhancements of inspiratory (I) drive. The aims of this study were to further characterize the coordinated activity of t-E neurons and test the hypothesis that peripheral chemoreceptors also modulate drive via inhibition of t-E neurons and disinhibition of their inspiratory neuron targets. Spike trains of 828 VRC neurons were acquired by multielectrode arrays along with phrenic nerve signals from 22 decerebrate, vagotomized, neuromuscularly blocked, artificially ventilated adult cats. Forty-eight of 191 t-E neurons fired synchronously with another t-E neuron as indicated by cross-correlogram central peaks; 32 of the 39 synchronous pairs were elements of groups with mutual pairwise correlations. Gravitational clustering identified fluctuations in t-E neuron synchrony. A network model supported the prediction that inhibitory populations with spike synchrony reduce target neuron firing probabilities, resulting in offset or central correlogram troughs. In five animals, stimulation of carotid chemoreceptors evoked changes in the firing rates of 179 of 240 neurons. Thirty-two neuron pairs had correlogram troughs consistent with convergent and divergent t-E inhibition of I cells and disinhibitory enhancement of drive. Four of 10 t-E neurons that responded to sequential stimulation of peripheral and central chemoreceptors triggered 25 cross-correlograms with offset features. The results support the hypothesis that multiple afferent systems dynamically tune inspiratory drive in part via coordinated t-E neurons.
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Affiliation(s)
- L S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - S C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - M M Ott
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - J B Dean
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - D C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - R O'Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - K F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - B G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
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Gourévitch B, Mellen N. The preBötzinger complex as a hub for network activity along the ventral respiratory column in the neonate rat. Neuroimage 2014; 98:460-74. [DOI: 10.1016/j.neuroimage.2014.04.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 04/10/2014] [Accepted: 04/29/2014] [Indexed: 01/07/2023] Open
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Multiscale fingerprinting of neuronal functional connectivity. Brain Struct Funct 2014; 220:2967-82. [PMID: 25056933 DOI: 10.1007/s00429-014-0838-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/30/2014] [Indexed: 12/22/2022]
Abstract
Current cellular-based connectomics approaches aim to delineate the functional or structural organizations of mammalian brain circuits through neuronal activity mapping and/or axonal tracing. To discern possible connectivity between functionally identified neurons in widely distributed brain circuits, reliable and efficient network-based approaches of cross-registering or cross-correlating such functional-structural data are essential. Here, a novel cross-correlation approach that exploits multiple timing-specific, response-specific, and cell-specific neuronal characteristics as coincident fingerprint markers at the systems, network, and cellular levels is proposed. Application of this multiscale temporal-cellular coincident fingerprinting assay to the respiratory central pattern generator network in rats revealed a descending excitatory pathway with characteristic activity pattern and projecting from a distinct neuronal population in pons to its counterparts in medulla that control the post-inspiratory phase of the respiratory rhythm important for normal breathing, airway protection, and respiratory-vocalization coordination. This enabling neurotracing approach may prove valuable for functional connectivity mapping of other brain circuits.
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Nieto-Posadas A, Flores-Martínez E, Lorea-Hernández JJ, Rivera-Angulo AJ, Pérez-Ortega JE, Bargas J, Peña-Ortega F. Change in network connectivity during fictive-gasping generation in hypoxia: prevention by a metabolic intermediate. Front Physiol 2014; 5:265. [PMID: 25101002 PMCID: PMC4107943 DOI: 10.3389/fphys.2014.00265] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/25/2014] [Indexed: 11/13/2022] Open
Abstract
The neuronal circuit in charge of generating the respiratory rhythms, localized in the pre-Bötzinger complex (preBötC), is configured to produce fictive-eupnea during normoxia and reconfigures to produce fictive-gasping during hypoxic conditions in vitro. The mechanisms involved in such reconfiguration have been extensively investigated by cell-focused studies, but the actual changes at the network level remain elusive. Since a failure to generate gasping has been linked to Sudden Infant Death Syndrome (SIDS), the study of gasping generation and pharmacological approaches to promote it may have clinical relevance. Here, we study the changes in network dynamics and circuit reconfiguration that occur during the transition to fictive-gasping generation in the brainstem slice preparation by recording the preBötC with multi-electrode arrays and assessing correlated firing among respiratory neurons or clusters of respiratory neurons (multiunits). We studied whether the respiratory network reconfiguration in hypoxia involves changes in either the number of active respiratory elements, the number of functional connections among elements, or the strength of these connections. Moreover, we tested the influence of isocitrate, a Krebs cycle intermediate that has recently been shown to promote breathing, on the configuration of the preBötC circuit during normoxia and on its reconfiguration during hypoxia. We found that, in contrast to previous suggestions based on cell-focused studies, the number and the overall activity of respiratory neurons change only slightly during hypoxia. However, hypoxia induces a reduction in the strength of functional connectivity within the circuit without reducing the number of connections. Isocitrate prevented this reduction during hypoxia while increasing the strength of network connectivity. In conclusion, we provide an overview of the configuration of the respiratory network under control conditions and how it is reconfigured during fictive-gasping. Additionally, our data support the use of isocitrate to favor respiratory rhythm generation under normoxia and to prevent some of the changes in the respiratory network under hypoxic conditions.
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Affiliation(s)
- Andrés Nieto-Posadas
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
| | - Ernesto Flores-Martínez
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
| | - Jonathan-Julio Lorea-Hernández
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
| | - Ana-Julia Rivera-Angulo
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
| | - Jesús-Esteban Pérez-Ortega
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México México D.F., México
| | - José Bargas
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México México D.F., México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
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Damasceno RS, Takakura AC, Moreira TS. Regulation of the chemosensory control of breathing by Kölliker-Fuse neurons. Am J Physiol Regul Integr Comp Physiol 2014; 307:R57-67. [PMID: 24760995 DOI: 10.1152/ajpregu.00024.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Kölliker-Fuse region (KF) and the lateral parabrachial nucleus (LPBN) have been implicated in the maintenance of cardiorespiratory control. Here, we evaluated the involvement of the KF region and the LPBN in cardiorespiratory responses elicited by chemoreceptor activation in unanesthetized rats. Male Wistar rats (280-330 g; n = 5-9/group) with bilateral stainless-steel guide cannulas implanted in the KF region or the LPBN were used. Injection of muscimol (100 and 200 pmol/100 nl) in the KF region decreased resting ventilation (1,140 ± 68 and 978 ± 100 vs. saline: 1,436 ± 155 ml·kg(-1)·min(-1)), without changing mean arterial pressure (MAP) and heart rate (HR). Bilateral injection of the GABA-A antagonist bicuculline (1 nmol/100 nl) in the KF blocked the inhibitory effect on ventilation (1,418 ± 138 vs. muscimol: 978 ± 100 ml·kg(-1)·min(-1)) elicited by muscimol. Muscimol injection in the KF reduced the increase in ventilation produced by hypoxia (8% O2) (1,827 ± 61 vs. saline: 3,179 ± 325 ml·kg(-1)·min(-1)) or hypercapnia (7% CO2) (1,488 ± 277 vs. saline: 3,539 ± 374 ml·kg(-1)·min(-1)) in unanesthetized rats. Bilateral injection of bicuculline in the KF blocked the decrease in ventilation produced by muscimol in the KF during peripheral or central chemoreflex activation. Bilateral injection of muscimol in the LPBN did not change resting ventilation or the increase in ventilation elicited by hypoxia or hypercapnia. The results of the present study suggest that the KF region, but not the LPBN, has mechanisms to control ventilation in resting, hypoxic, or hypercapnic conditions in unanesthetized rats.
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Affiliation(s)
- Rosélia S Damasceno
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil; and
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil; and
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Hirabayashi T, Miyashita Y. Computational principles of microcircuits for visual object processing in the macaque temporal cortex. Trends Neurosci 2014; 37:178-87. [DOI: 10.1016/j.tins.2014.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/03/2014] [Accepted: 01/06/2014] [Indexed: 01/04/2023]
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Abstract
Pontine respiratory nuclei provide synaptic input to medullary rhythmogenic circuits to shape and adapt the breathing pattern. An understanding of this statement depends on appreciating breathing as a behavior, rather than a stereotypic rhythm. In this review, we focus on the pontine-mediated inspiratory off-switch (IOS) associated with postinspiratory glottal constriction. Further, IOS is examined in the context of pontine regulation of glottal resistance in response to multimodal sensory inputs and higher commands, which in turn rules timing, duration, and patterning of respiratory airflow. In addition, network plasticity in respiratory control emerges during the development of the pons. Synaptic plasticity is required for dynamic and efficient modulation of the expiratory breathing pattern to cope with rapid changes from eupneic to adaptive breathing linked to exploratory (foraging and sniffing) and expulsive (vocalizing, coughing, sneezing, and retching) behaviors, as well as conveyance of basic emotions. The speed and complexity of changes in the breathing pattern of behaving animals implies that "learning to breathe" is necessary to adjust to changing internal and external states to maintain homeostasis and survival.
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Affiliation(s)
- Mathias Dutschmann
- Florey Neurosciences Institutes, University of Melbourne, Victoria, Australia.
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36
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Hirabayashi T, Takeuchi D, Tamura K, Miyashita Y. Microcircuits for Hierarchical Elaboration of Object Coding Across Primate Temporal Areas. Science 2013; 341:191-5. [DOI: 10.1126/science.1236927] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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37
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Molkov YI, Bacak BJ, Dick TE, Rybak IA. Control of breathing by interacting pontine and pulmonary feedback loops. Front Neural Circuits 2013; 7:16. [PMID: 23408512 PMCID: PMC3570896 DOI: 10.3389/fncir.2013.00016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 01/24/2013] [Indexed: 12/20/2022] Open
Abstract
The medullary respiratory network generates respiratory rhythm via sequential phase switching, which in turn is controlled by multiple feedbacks including those from the pons and nucleus tractus solitarii; the latter mediates pulmonary afferent feedback to the medullary circuits. It is hypothesized that both pontine and pulmonary feedback pathways operate via activation of medullary respiratory neurons that are critically involved in phase switching. Moreover, the pontine and pulmonary control loops interact, so that pulmonary afferents control the gain of pontine influence of the respiratory pattern. We used an established computational model of the respiratory network (Smith et al., 2007) and extended it by incorporating pontine circuits and pulmonary feedback. In the extended model, the pontine neurons receive phasic excitatory activation from, and provide feedback to, medullary respiratory neurons responsible for the onset and termination of inspiration. The model was used to study the effects of: (1) "vagotomy" (removal of pulmonary feedback), (2) suppression of pontine activity attenuating pontine feedback, and (3) these perturbations applied together on the respiratory pattern and durations of inspiration (T(I)) and expiration (T(E)). In our model: (a) the simulated vagotomy resulted in increases of both T(I) and T(E), (b) the suppression of pontine-medullary interactions led to the prolongation of T(I) at relatively constant, but variable T(E), and (c) these perturbations applied together resulted in "apneusis," characterized by a significantly prolonged T(I). The results of modeling were compared with, and provided a reasonable explanation for, multiple experimental data. The characteristic changes in T(I) and T(E) demonstrated with the model may represent characteristic changes in the balance between the pontine and pulmonary feedback control mechanisms that may reflect specific cardio-respiratory disorders and diseases.
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Affiliation(s)
- Yaroslav I Molkov
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA ; Department of Mathematical Sciences, Indiana University - Purdue University Indianapolis, IN, USA
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Smith JC, Abdala APL, Borgmann A, Rybak IA, Paton JFR. Brainstem respiratory networks: building blocks and microcircuits. Trends Neurosci 2012; 36:152-62. [PMID: 23254296 DOI: 10.1016/j.tins.2012.11.004] [Citation(s) in RCA: 269] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 11/10/2012] [Accepted: 11/12/2012] [Indexed: 01/18/2023]
Abstract
Breathing movements in mammals are driven by rhythmic neural activity generated within spatially and functionally organized brainstem neural circuits comprising the respiratory central pattern generator (CPG). This rhythmic activity provides homeostatic regulation of gases in blood and tissues and integrates breathing with other motor acts. We review new insights into the spatial-functional organization of key neural microcircuits of this CPG from recent multidisciplinary experimental and computational studies. The emerging view is that the microcircuit organization within the CPG allows the generation of multiple rhythmic breathing patterns and adaptive switching between them, depending on physiological or pathophysiological conditions. These insights open the possibility for site- and mechanism-specific interventions to treat various disorders of the neural control of breathing.
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Affiliation(s)
- Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
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O’Connor R, Segers LS, Morris KF, Nuding SC, Pitts T, Bolser DC, Davenport PW, Lindsey BG. A joint computational respiratory neural network-biomechanical model for breathing and airway defensive behaviors. Front Physiol 2012; 3:264. [PMID: 22934020 PMCID: PMC3429040 DOI: 10.3389/fphys.2012.00264] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 06/24/2012] [Indexed: 11/13/2022] Open
Abstract
Data-driven computational neural network models have been used to study mechanisms for generating the motor patterns for breathing and breathing related behaviors such as coughing. These models have commonly been evaluated in open loop conditions or with feedback of lung volume simply represented as a filtered version of phrenic motor output. Limitations of these approaches preclude assessment of the influence of mechanical properties of the musculoskeletal system and motivated development of a biomechanical model of the respiratory muscles, airway, and lungs using published measures from human subjects. Here we describe the model and some aspects of its behavior when linked to a computational brainstem respiratory network model for breathing and airway defensive behavior composed of discrete "integrate and fire" populations. The network incorporated multiple circuit paths and operations for tuning inspiratory drive suggested by prior work. Results from neuromechanical system simulations included generation of a eupneic-like breathing pattern and the observation that increased respiratory drive and operating volume result in higher peak flow rates during cough, even when the expiratory drive is unchanged, or when the expiratory abdominal pressure is unchanged. Sequential elimination of the model's sources of inspiratory drive during cough also suggested a role for disinhibitory regulation via tonic expiratory neurons, a result that was subsequently supported by an analysis of in vivo data. Comparisons with antecedent models, discrepancies with experimental results, and some model limitations are noted.
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Affiliation(s)
- Russell O’Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South FloridaTampa, FL, USA
| | - Lauren S. Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South FloridaTampa, FL, USA
| | - Kendall F. Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South FloridaTampa, FL, USA
| | - Sarah C. Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South FloridaTampa, FL, USA
| | - Teresa Pitts
- Department of Physiological Sciences, College of Veterinary Medicine, University of FloridaGainesville, FL, USA
| | - Donald C. Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of FloridaGainesville, FL, USA
| | - Paul W. Davenport
- Department of Physiological Sciences, College of Veterinary Medicine, University of FloridaGainesville, FL, USA
| | - Bruce G. Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South FloridaTampa, FL, USA
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Lindsey BG, Rybak IA, Smith JC. Computational models and emergent properties of respiratory neural networks. Compr Physiol 2012; 2:1619-70. [PMID: 23687564 PMCID: PMC3656479 DOI: 10.1002/cphy.c110016] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Computational models of the neural control system for breathing in mammals provide a theoretical and computational framework bringing together experimental data obtained from different animal preparations under various experimental conditions. Many of these models were developed in parallel and iteratively with experimental studies and provided predictions guiding new experiments. This data-driven modeling approach has advanced our understanding of respiratory network architecture and neural mechanisms underlying generation of the respiratory rhythm and pattern, including their functional reorganization under different physiological conditions. Models reviewed here vary in neurobiological details and computational complexity and span multiple spatiotemporal scales of respiratory control mechanisms. Recent models describe interacting populations of respiratory neurons spatially distributed within the Bötzinger and pre-Bötzinger complexes and rostral ventrolateral medulla that contain core circuits of the respiratory central pattern generator (CPG). Network interactions within these circuits along with intrinsic rhythmogenic properties of neurons form a hierarchy of multiple rhythm generation mechanisms. The functional expression of these mechanisms is controlled by input drives from other brainstem components,including the retrotrapezoid nucleus and pons, which regulate the dynamic behavior of the core circuitry. The emerging view is that the brainstem respiratory network has rhythmogenic capabilities at multiple levels of circuit organization. This allows flexible, state-dependent expression of different neural pattern-generation mechanisms under various physiological conditions,enabling a wide repertoire of respiratory behaviors. Some models consider control of the respiratory CPG by pulmonary feedback and network reconfiguration during defensive behaviors such as cough. Future directions in modeling of the respiratory CPG are considered.
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Affiliation(s)
- Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology and Neuroscience Program, University of South Florida College of Medicine, Tampa, Florida, USA.
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Mellen NM, Thoby-Brisson M. Respiratory circuits: development, function and models. Curr Opin Neurobiol 2012; 22:676-85. [PMID: 22281058 DOI: 10.1016/j.conb.2012.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 01/04/2012] [Accepted: 01/04/2012] [Indexed: 01/27/2023]
Abstract
Breathing is a rhythmic motor behavior generated and controlled by hindbrain neuronal networks. Respiratory motor output arises from two distinct, but functionally interacting, rhythmogenic networks: the pre-Bötzinger complex (preBötC) and the retrotrapezoïd nucleus/parafacial respiratory group (RTN/pFRG). This review outlines recent advances in delineating the genetic specification of the neuronal constituents of these two rhythmogenic networks, their respective roles in respiratory function and how they interact to constitute a functional respiratory circuit ensemble. The often lethal consequences of disruption to these networks found in naturally occurring developmental disorders, transgenic animals, and highly specific lesion studies are described. In addition, we discuss how recent computational models enhance our understanding of how respiratory networks generate and regulate respiratory behavior.
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Affiliation(s)
- Nicholas M Mellen
- Department of Pediatrics, University of Louisville, School of Medicine, Louisville, KY 40202-3830, USA
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Costa-Silva JH, Zoccal DB, Machado BH. Chronic intermittent hypoxia alters glutamatergic control of sympathetic and respiratory activities in the commissural NTS of rats. Am J Physiol Regul Integr Comp Physiol 2011; 302:R785-93. [PMID: 22204959 DOI: 10.1152/ajpregu.00363.2011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Sympathetic overactivity and altered respiratory control are commonly observed after chronic intermittent hypoxia (CIH) exposure. However, the central mechanisms underlying such neurovegetative dysfunctions remain unclear. Herein, we hypothesized that CIH (6% O(2) every 9 min, 8 h/day, 10 days) in juvenile rats alters glutamatergic transmission in the commissural nucleus tractus solitarius (cNTS), a pivotal site for integration of peripheral chemoreceptor inputs. Using an in situ working heart-brain stem preparation, we found that l-glutamate microinjections (1, 3, and 10 mM) into the cNTS of control rats (n = 8) evoked increases in thoracic sympathetic nerve (tSN) and central vagus nerve (cVN) activities combined with inhibition of phrenic nerve (PN) activity. Besides, the ionotropic glutamatergic receptor antagonism with kynurenic acid (KYN; 250 mM) in the cNTS of control group (n = 7) increased PN burst duration and frequency. In the CIH group (n = 10), the magnitude of l-glutamate-induced cVN excitation was smaller, and the PN inhibitory response was blunted (P < 0.05). In addition, KYN microinjections into the cNTS of CIH rats (n = 9) did not alter PN burst duration and produced smaller increases in its frequency compared with controls. Moreover, KYN microinjections into the cNTS attenuated the sympathoexcitatory response to peripheral chemoreflex activation in control but not in CIH rats (P < 0.05). These functional CIH-induced alterations were accompanied by a significant 10% increase of N-methyl-D-aspartate receptor 1 (NMDAR1) and glutamate receptor 2/3 (GluR2/3) receptor subunit density in the cNTS (n = 3-8, P < 0.05), evaluated by Western blot analysis. These data indicate that glutamatergic transmission is altered in the cNTS of CIH rats and may contribute to the sympathetic and respiratory changes observed in this experimental model.
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Affiliation(s)
- João H Costa-Silva
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
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43
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Ott MM, Nuding SC, Segers LS, O'Connor R, Morris KF, Lindsey BG. Central chemoreceptor modulation of breathing via multipath tuning in medullary ventrolateral respiratory column circuits. J Neurophysiol 2011; 107:603-17. [PMID: 21994272 DOI: 10.1152/jn.00808.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ventrolateral respiratory column (VRC) circuits that modulate breathing in response to changes in central chemoreceptor drive are incompletely understood. We employed multielectrode arrays and spike train correlation methods to test predictions of the hypothesis that pre-Bötzinger complex (pre-BötC) and retrotrapezoid nucleus/parafacial (RTN-pF) circuits cooperate in chemoreceptor-evoked tuning of ventral respiratory group (VRG) inspiratory neurons. Central chemoreceptors were selectively stimulated by injections of CO(2)-saturated saline into the vertebral artery in seven decerebrate, vagotomized, neuromuscularly blocked, and artificially ventilated cats. Among sampled neurons in the Bötzinger complex (BötC)-to-VRG region, 70% (161 of 231) had a significant change in firing rate after chemoreceptor stimulation, as did 70% (101 of 144) of the RTN-pF neurons. Other responsive neurons (24 BötC-VRG; 11 RTN-pF) had a change in the depth of respiratory modulation without a significant change in average firing rate. Seventy BötC-VRG chemoresponsive neurons triggered 189 offset-feature correlograms (96 peaks; 93 troughs) with at least one responsive BötC-VRG cell. Functional input from at least one RTN-pF cell could be inferred for 45 BötC-VRG neurons (19%). Eleven RTN-pF cells were correlated with more than one BötC-VRG target neuron, providing evidence for divergent connectivity. Thirty-seven RTN-pF neurons, 24 of which were chemoresponsive, were correlated with at least one chemoresponsive BötC-VRG neuron. Correlation linkage maps and spike-triggered averages of phrenic nerve signals suggest transmission of chemoreceptor drive via a multipath network architecture: RTN-pF modulation of pre-BötC-VRG rostral-to-caudal excitatory inspiratory neuron chains is tuned by feedforward and recurrent inhibition from other inspiratory neurons and from "tonic" expiratory neurons.
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Affiliation(s)
- Mackenzie M Ott
- Department of Molecular Pharmacology and Physiology, College of Medicine, University of South Florida, Tampa, Florida 33612-4799, USA
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44
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Davenport PW, Bolser DC, Morris KF. Swallow remodeling of respiratory neural networks. Head Neck 2011; 33 Suppl 1:S8-13. [PMID: 21901777 DOI: 10.1002/hed.21845] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2011] [Indexed: 11/06/2022] Open
Abstract
Swallow is defined as the coordinated neuromuscular activity of the mouth, pharynx, larynx, and esophagus. Movement of a bolus and air must be coordinated by swallow remodeling of the respiratory pattern. The brainstem contains respiratory and swallow neural control networks that generate the pattern for breathing and swallow. Swallow control of respiration is proposed to be through recruitment of swallow neural elements that retask existing respiratory neural network elements. Swallow reconfiguration of the respiratory neural network is fundamental to airway protection and integrated with other airway protective reflexes. Thus, swallow, breathing, cough, and other airway defensive behaviors are produced by a central neural motor system that shares elements. It is hypothesized that swallow and airway defensive behaviors are controlled by a recruited behavioral control assembly system that is organized in a fashion that allows for precise coordination of the expression of these behaviors to maintain airway protection.
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Affiliation(s)
- Paul W Davenport
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA.
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45
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Poliacek I, Morris KF, Lindsey BG, Segers LS, Rose MJ, Corrie LWC, Wang C, Pitts TE, Davenport PW, Bolser DC. Blood pressure changes alter tracheobronchial cough: computational model of the respiratory-cough network and in vivo experiments in anesthetized cats. J Appl Physiol (1985) 2011; 111:861-73. [PMID: 21719729 PMCID: PMC3174787 DOI: 10.1152/japplphysiol.00458.2011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 06/27/2011] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis, motivated in part by a coordinated computational cough network model, that alterations of mean systemic arterial blood pressure (BP) influence the excitability and motor pattern of cough. Model simulations predicted suppression of coughing by stimulation of arterial baroreceptors. In vivo experiments were conducted on anesthetized spontaneously breathing cats. Cough was elicited by mechanical stimulation of the intrathoracic airways. Electromyograms (EMG) of inspiratory parasternal, expiratory abdominal, laryngeal posterior cricoarytenoid (PCA), and thyroarytenoid muscles along with esophageal pressure (EP) and BP were recorded. Transiently elevated BP significantly reduced cough number, cough-related inspiratory, and expiratory amplitudes of EP, peak parasternal and abdominal EMG, and maximum of PCA EMG during the expulsive phase of cough, and prolonged the cough inspiratory and expiratory phases as well as cough cycle duration compared with control coughs. Latencies from the beginning of stimulation to the onset of cough-related diaphragm and abdominal activities were increased. Increases in BP also elicited bradycardia and isocapnic bradypnea. Reductions in BP increased cough number; elevated inspiratory EP amplitude and parasternal, abdominal, and inspiratory PCA EMG amplitudes; decreased total cough cycle duration; shortened the durations of the cough expiratory phase and cough-related abdominal discharge; and shortened cough latency compared with control coughs. Reduced BP also produced tachycardia, tachypnea, and hypocapnic hyperventilation. These effects of BP on coughing likely originate from interactions between barosensitive and respiratory brainstem neuronal networks, particularly by modulation of respiratory neurons within multiple respiration/cough-related brainstem areas by baroreceptor input.
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Affiliation(s)
- Ivan Poliacek
- Dept. of Physiological Sciences, College of Veterinary Medicine, Univ. of Florida, Gainesville, FL 32610, USA.
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46
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Dhingra RR, Jacono FJ, Fishman M, Loparo KA, Rybak IA, Dick TE. Vagal-dependent nonlinear variability in the respiratory pattern of anesthetized, spontaneously breathing rats. J Appl Physiol (1985) 2011; 111:272-84. [PMID: 21527661 DOI: 10.1152/japplphysiol.91196.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Physiological rhythms, including respiration, exhibit endogenous variability associated with health, and deviations from this are associated with disease. Specific changes in the linear and nonlinear sources of breathing variability have not been investigated. In this study, we used information theory-based techniques, combined with surrogate data testing, to quantify and characterize the vagal-dependent nonlinear pattern variability in urethane-anesthetized, spontaneously breathing adult rats. Surrogate data sets preserved the amplitude distribution and linear correlations of the original data set, but nonlinear correlation structure in the data was removed. Differences in mutual information and sample entropy between original and surrogate data sets indicated the presence of deterministic nonlinear or stochastic non-Gaussian variability. With vagi intact (n = 11), the respiratory cycle exhibited significant nonlinear behavior in templates of points separated by time delays ranging from one sample to one cycle length. After vagotomy (n = 6), even though nonlinear variability was reduced significantly, nonlinear properties were still evident at various time delays. Nonlinear deterministic variability did not change further after subsequent bilateral microinjection of MK-801, an N-methyl-D-aspartate receptor antagonist, in the Kölliker-Fuse nuclei. Reversing the sequence (n = 5), blocking N-methyl-D-aspartate receptors bilaterally in the dorsolateral pons significantly decreased nonlinear variability in the respiratory pattern, even with the vagi intact, and subsequent vagotomy did not change nonlinear variability. Thus both vagal and dorsolateral pontine influences contribute to nonlinear respiratory pattern variability. Furthermore, breathing dynamics of the intact system are mutually dependent on vagal and pontine sources of nonlinear complexity. Understanding the structure and modulation of variability provides insight into disease effects on respiratory patterning.
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Affiliation(s)
- R R Dhingra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
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Molkov YI, Zoccal DB, Moraes DJA, Paton JFR, Machado BH, Rybak IA. Intermittent hypoxia-induced sensitization of central chemoreceptors contributes to sympathetic nerve activity during late expiration in rats. J Neurophysiol 2011; 105:3080-91. [PMID: 21471394 DOI: 10.1152/jn.00070.2011] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hypertension elicited by chronic intermittent hypoxia (CIH) is associated with elevated activity of the thoracic sympathetic nerve (tSN) that exhibits an enhanced respiratory modulation reflecting a strengthened interaction between respiratory and sympathetic networks within the brain stem. Expiration is a passive process except for special metabolic conditions such as hypercapnia, when it becomes active through phasic excitation of abdominal motor nerves (AbN) in late expiration. An increase in CO(2) evokes late-expiratory (late-E) discharges phase-locked to phrenic bursts with the frequency increasing quantally as hypercapnia increases. In rats exposed to CIH, the late-E discharges synchronized in AbN and tSN emerge in normocapnia. To elucidate the possible neural mechanisms underlying these phenomena, we extended our computational model of the brain stem respiratory network by incorporating a population of presympathetic neurons in the rostral ventrolateral medulla that received inputs from the pons, medullary respiratory compartments, and retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG). Our simulations proposed that CIH conditioning increases the CO(2) sensitivity of RTN/pFRG neurons, causing a reduction in both the CO(2) threshold for emerging the late-E activity in AbN and tSN and the hypocapnic threshold for apnea. Using the in situ rat preparation, we have confirmed that CIH-conditioned rats under normal conditions exhibit synchronized late-E discharges in AbN and tSN similar to those observed in control rats during hypercapnia. Moreover, the hypocapnic threshold for apnea was significantly lowered in CIH-conditioned rats relative to that in control rats. We conclude that CIH may sensitize central chemoreception and that this significantly contributes to the neural impetus for generation of sympathetic activity and hypertension.
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Affiliation(s)
- Yaroslav I Molkov
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
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48
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Ott MM, Nuding SC, Segers LS, Lindsey BG, Morris KF. Ventrolateral medullary functional connectivity and the respiratory and central chemoreceptor-evoked modulation of retrotrapezoid-parafacial neurons. J Neurophysiol 2011; 105:2960-75. [PMID: 21389310 DOI: 10.1152/jn.00262.2010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The medullary ventral respiratory column (VRC) of neurons is essential for respiratory motor pattern generation; however, the functional connections among these cells are not well understood. A rostral extension of the VRC, including the retrotrapezoid nucleus/parafacial region (RTN-pF), contains neurons responsive to local perturbations of CO(2)/pH. We addressed the hypothesis that both local RTN-pF interactions and functional connections from more caudal VRC compartments--extending from the Bötzinger and pre-Bötzinger complexes to the ventral respiratory group (Böt-VRG)--influence the respiratory modulation of RTN-pF neurons and their responses to central chemoreceptor and baroreflex activation. Spike trains from 294 RTN-pF and 490 Böt-VRG neurons were monitored with multielectrode arrays along with phrenic nerve activity in 14 decerebrate, vagotomized cats. Overall, 214 RTN-pF and 398 Böt-VRG neurons were respiratory modulated; 124 and 95, respectively, were cardiac modulated. Subsets of these neurons were tested with sequential, selective, transient stimulation of central chemoreceptors and arterial baroreceptors; each cell's response was evaluated and categorized according to the change in firing rate (if any) following the stimulus. Cross-correlation analysis was applied to 2,884 RTN-pF↔RTN-pF and 8,490 Böt-VRG↔RTN-pF neuron pairs. In total, 174 RTN-pF neurons (59.5%) had significant features in short-time scale correlations with other RTN-pF neurons. Of these, 49 neurons triggered cross-correlograms with offset peaks or troughs (n = 99) indicative of paucisynaptic excitation or inhibition of the target. Forty-nine Böt-VRG neurons (10.0%) were triggers in 74 Böt-VRG→RTN-pF correlograms with offset features, suggesting that Böt-VRG trigger neurons influence RTN-pF target neurons. The results support the hypothesis that local RTN-pF neuron interactions and inputs from Böt-VRG neurons jointly contribute to respiratory modulation of RTN-pF neuronal discharge patterns and promotion or limitation of their responses to central chemoreceptor and baroreceptor stimulation.
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Affiliation(s)
- Mackenzie M Ott
- Department of Molecular Pharmacology and Physiology and Neuroscience Program, School of Biomedical Sciences, University of South Florida College of Medicine, Tampa, Florida 33612-4799, USA
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Topchiy I, Radulovacki M, Waxman J, Carley DW. Impact of the vagal feedback on cardiorespiratory coupling in anesthetized rats. Respir Physiol Neurobiol 2010; 175:375-82. [PMID: 21199691 DOI: 10.1016/j.resp.2010.12.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 12/27/2010] [Accepted: 12/28/2010] [Indexed: 12/22/2022]
Abstract
Cardiorespiratory coupling can be significantly influenced by both pontine and vagal modulation of medullary motor and premotor areas. We investigated influences of the pontine intertrigeminal region (ITR) and peripheral vagal pathways on the coupling between systolic blood pressure (SBP) and respiration in 9 anesthetized rats. Glutamate injection into the ITR perturbed both respiration and SBP and decreased SBP-respiratory coherence (0.95±0.01 vs 0.89±0.02; (p=0.01). Intravenous infusion of serotonin (5-HT) produced apnea and hypertension and also decreased SBP-respiratory coherence (0.95±0.01 vs 0.72±0.06; p=0.04). Bilateral vagotomy eliminated the cardiorespiratory coherence perturbations induced by central (glutamate injection into the ITR: 0.89±0.03 vs 0.86±0.03; p=0.63) and peripheral (5-HT infusion: 0.89±0.03 vs 0.88±0.02; p=0.98) pharmacologic manipulations. Glutamate stimulation of the ITR postvagotomy increased the relative spectral power density of SBP in the respiratory frequency range (0.25±0.08 vs 0.55±0.06; p=0.01). The data suggest that SBP-respiratory coupling is largely mediated within the central nervous system, with vagal systems acting in a way that disrupts coherence during transient cardiorespiratory disturbances. Although decreased cardiorespiratory coherence may increase cardiac work during perturbations, this may be physiologically advantageous in restoring homeostatic equilibrium of respiration and blood pressure.
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Affiliation(s)
- Irina Topchiy
- Center for Narcolepsy, Sleep and Health Research, M/C 802, University of Illinois at Chicago, 845 South Damen Ave., Chicago, IL 60612, USA.
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Dunin-Barkowski W, Lovering A, Orem J, Baekey D, Dick T, Rybak I, Morris K, O’Connor R, Nuding S, Shannon R, Lindsey B. L-plotting—A method for visual analysis of physiological experimental and modeling multi-component data. Neurocomputing 2010. [DOI: 10.1016/j.neucom.2010.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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