Adaptive trends in respiratory control: a comparative perspective

2010 ◽  
Vol 299 (1) ◽  
pp. R1-R10 ◽  
Author(s):  
William K. Milsom
Keyword(s):  
Respiratory Rhythm ◽  
Respiratory Control ◽  
Respiratory Physiology ◽  
University Of Pennsylvania ◽  
Lower Airway ◽  
Pulmonary Mechanics ◽  
Breathing Patterns ◽  
The Central Nervous System ◽  
Metabolic Performance ◽  
The Cost

In 1941, August Krogh published a monograph entitled The Comparative Physiology of Respiratory Mechanisms (Philadelphia, PA: University of Pennsylvania Press, 1941). Since that time comparative studies have continued to contribute significantly to our understanding of the fundamentals of respiratory physiology and the adaptive trends in these processes that support a broad range of metabolic performance under demanding environmental conditions. This review specifically focuses on recent advances in our understanding of adaptive trends in respiratory control. Respiratory rhythm generators most likely arose from, and must remain integrated with, rhythm generators for chewing, suckling, and swallowing. Within the central nervous system there are multiple “segmental” rhythm generators, and through evolution there is a caudal shift in the predominant respiratory rhythm-generating site. All sites, however, may still be capable of producing or modulating respiratory rhythm under appropriate conditions. Expression of the respiratory rhythm is conditional on (tonic) input. Once the rhythm is expressed, it is often episodic as the basic medullary rhythm is turned on/off subject to a hierarchy of controls. Breathing patterns reflect differences in pulmonary mechanics resulting from differences in body wall and lung architecture and are modulated in different species by various combinations of upper and lower airway mechanoreceptors and arterial chemoreceptors to protect airways, reduce dead space ventilation, enhance gas exchange efficiency, and reduce the cost of breathing.

scholarly journals Central pathways of pulmonary and lower airway vagal afferents

2006 ◽  
Vol 101 (2) ◽  
pp. 618-627 ◽  
Author(s):  
Leszek Kubin ◽  
George F. Alheid ◽  
Edward J. Zuperku ◽  
Donald R. McCrimmon
Keyword(s):  
Motor Pattern ◽  
Respiratory Rhythm ◽  
Respiratory Control ◽  
Afferent Input ◽  
Second Order ◽  
Vagal Afferents ◽  
Ventrolateral Medulla ◽  
Lower Airway ◽  
C Fibers ◽  
P Cells

Lung sensory receptors with afferent fibers coursing in the vagus nerves are broadly divided into three groups: slowly (SAR) and rapidly (RAR) adapting stretch receptors and bronchopulmonary C fibers. Central terminations of each group are found in largely nonoverlapping regions of the caudal half of the nucleus of the solitary tract (NTS). Second order neurons in the pathways from these receptors innervate neurons located in respiratory-related regions of the medulla, pons, and spinal cord. The relative ease of selective activation of SARs, and to a lesser extent RARs, has allowed for more complete physiological and morphological characterization of the second and higher order neurons in these pathways than for C fibers. A subset of NTS neurons receiving afferent input from SARs (termed pump or P-cells) mediates the Breuer-Hering reflex and inhibits neurons receiving afferent input from RARs. P-cells and second order neurons in the RAR pathway also provide inputs to regions of the ventrolateral medulla involved in control of respiratory motor pattern, i.e., regions containing a predominance of bulbospinal premotor neurons, as well as regions containing respiratory rhythm-generating neurons. Axon collaterals from both P-cells and RAR interneurons, and likely from NTS interneurons in the C-fiber pathway, project to the parabrachial pontine region where they may contribute to plasticity in respiratory control and integration of respiratory control with other systems, including those that provide for voluntary control of breathing, sleep-wake behavior, and emotions.

scholarly journals Stabilizing immature breathing patterns of preterm infants using stochastic mechanosensory stimulation

2009 ◽  
Vol 107 (4) ◽  
pp. 1017-1027 ◽  
Author(s):  
Elisabeth Bloch-Salisbury ◽  
Premananda Indic ◽  
Frank Bednarek ◽  
David Paydarfar
Keyword(s):  
Preterm Infants ◽  
Respiratory Control ◽  
Behavioral State ◽  
Mean Square ◽  
Breathing Patterns ◽  
Nonlinear Properties ◽  
Improved Stability ◽  
Postconceptional Age ◽  
The Stability ◽  
Large Improvement

Breathing patterns in preterm infants consist of highly variable interbreath intervals (IBIs) that might originate from nonlinear properties of the respiratory oscillator and its input-output responses to peripheral and central signals. Here, we explore a property of nonlinear control, the potential for large improvement in the stability of breathing using low-level exogenous stochastic stimulation. Stimulation was administered to 10 preterm infants (postconceptional age: mean 33.3 wk, SD 1.7) using a mattress with embedded actuators that delivered small stochastic displacements (0.021 mm root mean square, 0.090 mm maximum, 30–60 Hz); this stimulus was subthreshold for causing arousal from sleep to wakefulness or other detectable changes in the behavioral state evaluated with polysomnography. We used a test-retest protocol with multiple 10-min intervals of stimulation, each paired with 10-min intervals of no stimulation. Stimulation induced an ∼50% reduction ( P = 0.003) in the variance of IBIs and an ∼50% reduction ( P = 0.002) in the incidence of IBIs > 5 s. The improved stability of eupneic breathing was associated with an ∼65% reduction ( P = 0.04) in the duration of O2 desaturation. Our findings suggest that nonlinear properties of the immature respiratory control system can be harnessed using afferent stimuli to stabilize eupneic breathing, thereby potentially reducing the incidence of apnea and hypoxia.

scholarly journals Site-specific effects on respiratory rhythm and pattern of ibotenic acid injections in the pontine respiratory group of goats

2010 ◽  
Vol 109 (1) ◽  
pp. 171-188 ◽  
Author(s):  
J. M. Bonis ◽  
S. E. Neumueller ◽  
K. L. Krause ◽  
T. Kiner ◽  
A. Smith ◽  
...  
Keyword(s):  
Pulmonary Ventilation ◽  
Respiratory Rhythm ◽  
Ibotenic Acid ◽  
Pattern Generation ◽  
Respiratory Pattern ◽  
Breathing Patterns ◽  
Site Specific ◽  
Specific Effects ◽  
Tegmental Nuclei ◽  
Pontine Respiratory Group

To probe further the contributions of the rostral pons to eupneic respiratory rhythm and pattern, we tested the hypothesis that ibotenic acid (IA) injections in the pontine respiratory group (PRG) would disrupt eupneic respiratory rhythm and pattern in a site- and state-specific manner. In 15 goats, cannulas were bilaterally implanted into the rostral pontine tegmental nuclei (RPTN; n = 3), the lateral (LPBN; n = 4) or medial parabrachial nuclei (MPBN; n = 4), or the Kölliker-Fuse nucleus (KFN; n = 4). After recovery from surgery, 1- and 10-μl injections (1 wk apart) of IA were made bilaterally through the implanted cannulas during the day. Over the first 5 h after the injections, there were site-specific ventilatory effects, with increased ( P < 0.05) breathing frequency in RPTN-injected goats, increased ( P < 0.05) pulmonary ventilation (V̇i) in LPBN-injected goats, no effect ( P < 0.05) in MPBN-injected goats, and a biphasic V̇i response ( P < 0.05) in KFN-injected goats. This biphasic response consisted of a hyperpnea for 30 min, followed by a prolonged hypopnea and hypoventilation with marked apneas, apneusis-like breathing patterns, and/or shifts in the temporal relationships between inspiratory flow and diaphragm activity. In the awake state, 10–15 h after the 1-μl injections, the number of apneas was greater ( P < 0.05) than during other studies at night. However, there were no incidences of terminal apneas. Breathing rhythm and pattern were normal 22 h after the injections. Subsequent histological analysis revealed that for goats with cannulas implanted into the KFN, there were nearly 50% fewer neurons ( P < 0.05) in all three PRG subnuclei than in control goats. We conclude that in awake goats, 1) IA injections into the PRG have site-specific effects on breathing, and 2) the KFN contributes to eupneic respiratory pattern generation.

Neurogenic Breathing Patterns

2019 ◽  
pp. 115-117
Author(s):  
Eelco F. M. Wijdicks
Keyword(s):  
Central Nervous System ◽  
Acute Coronary Syndrome ◽  
Cardiac Arrhythmias ◽  
Cardiac Electrophysiology ◽  
Cardiac Event ◽  
Acute Injury ◽  
Breathing Patterns ◽  
Coronary Syndrome ◽  
The Central Nervous System ◽  
Pressure Surge

Abnormalities of cardiac function and cardiac electrophysiology are not uncommon in patients with acute injury to the central nervous system, and cardiac abnormalities may be the initial signs when these patients are first evaluated. Some patients have findings that suggest an acute coronary syndrome but disappear after the intracranial pressure surge subsides. The clinician must consider underlying neurologic disease when a patient presents with cardiac arrhythmias, new-onset pulmonary edema, hypotension, or cardiogenic shock with characteristics atypical for a primary cardiac event if the patient is in an otherwise unexplained comatose state.

The Development of a Human Gait Model With Predictive Capability and the Simulation of Able-Bodied Gait

2015 ◽  
Author(s):  
Jinming Sun ◽  
Shaoli Wu ◽  
Philip A. Voglewede
Keyword(s):  
Control Algorithm ◽  
Human Subjects ◽  
Human Gait ◽  
Control Input ◽  
Trial And Error ◽  
Predictive Capability ◽  
Gait Simulation ◽  
Plant Model ◽  
The Central Nervous System ◽  
The Cost

The development of current prostheses and orthoses typically follows a trial and error approach where the devices are designed based on experience, tried on human subjects and then redesigned iteratively. This design approach is costly, risky and time consuming. A predictive human gait model is desired such that prostheses can be virtually tested so that their performance can be predicted qualitatively, the cost can be reduced, and the risks can be minimized. The development of such a model is explained in this paper. The developed model includes two parts: a plant model which represents the forward dynamics of human gait and a controller which represents the central nervous system (CNS). The development of the plant model is explained in a different paper. This paper focuses on the control algorithm development and able-bodied gait simulation. The controller proposed in this paper utilizes model predictive control (MPC). MPC uses an internal model to predict the output in advance, compare the predicted output to the reference, and optimize control input so that the error between them is minimal. The developed predictive human gait model was validated by simulating able-bodied human gait. The simulation results showed that the controller is able to simulate the kinematic output close to experimental data.

Rapid and transient excitation of respiration mediated by central chemoreceptor

1988 ◽  
Vol 64 (4) ◽  
pp. 1369-1375 ◽  
Author(s):  
H. Arita ◽  
N. Kogo ◽  
K. Ichikawa
Keyword(s):  
Control System ◽  
Dynamic Properties ◽  
Respiratory Rhythm ◽  
Respiratory Control ◽  
Facilitatory Effect ◽  
Onset Latency ◽  
Central Chemoreceptors ◽  
Spontaneously Breathing ◽  
Respiratory Phases ◽  
Stimulation Of

We evaluated rapid and transient changes in phrenic nerve (PN) and internal intercostal (IIC) activities when 0.2-0.5 ml of saline saturated with 100% CO2 was injected into the vertebral artery during various respiratory phases in decerebrated spontaneously breathing cats. The injections evoked an initial transient inhibition of ongoing PN or IIC activity with a mean onset latency of 0.17 s, followed by excitation of subsequent respiratory activities with an onset latency ranging from 0.4 to 2.7 s; the average onset latency of expiratory excitation (1.49 s) was significantly longer than that of inspiratory facilitation (0.89 s). The initial inhibitory responses were analogous to reflex effects of injections of phenyl biguanide, indicating that the initial inhibition was due to activation of vascular nociceptors and the subsequent excitation was due to stimulation of the central chemoreceptors. In addition, CO2-saline injections during hypocapnic apnea developed a quick reappearance of respiratory rhythm, and the first facilitatory effect appeared in tonic IIC activity, which became more active before rhythm started. In summary, the present study, by use of a technique of vertebral arterial injections of 100% CO2-saline, revealed dynamic properties of respiratory control system mediated by central chemoreceptors and vascular nociceptors.

scholarly journals Aminophylline modulation of the mouse respiratory network changes during postnatal maturation

2000 ◽  
Vol 89 (5) ◽  
pp. 2015-2022 ◽  
Author(s):  
B. Wilken ◽  
J. M. Ramirez ◽  
F. Hanefeld ◽  
D. W. Richter
Keyword(s):  
Developmental Change ◽  
Respiratory Rhythm ◽  
Respiratory Control ◽  
Network Activity ◽  
Signal Pathways ◽  
Control Mechanisms ◽  
Patch Clamp Technique ◽  
Postnatal Maturation ◽  
Respiratory Network ◽  
Synaptic Drive

Aminophylline is a respiratory stimulant commonly used for the treatment of central apnea. Experiences from clinical practice, however, revealed that aminophylline is not reliably effective in preterm infants, whereas it is normally effective in infants and mature patients. In an established animal model for postnatal development of respiratory control mechanisms, we therefore examined the hypothesis that the clinical observations reflect a developmental change in the sensitivity of the central respiratory network to methylxanthines. The medullary respiratory network was isolated at different postnatal ages ( postnatal days 1–13; P1–P13) in a transverse mouse brain stem slice preparation. This preparation contains the pre-Bötzinger complex (PBC), a region that is critical for generation of respiratory rhythm. Spontaneous rhythmic respiratory activity was recorded from the hypoglossal (XII) rootlets and from neurons in the PBC by using the whole cell patch clamp technique. Bath-applied aminophylline [20 μM] increased the frequency (+41%) in neonatal animals (P1–P6) without affecting the amplitude of respiratory burst activity in XII rootlets. The same concentration of aminophylline did not have any significant effect on the frequency of respiratory XII bursts but increased the amplitude (+31%) in juvenile animals (P7–P13). In the same age group, aminophylline also augmented the amplitude and the duration of respiratory synaptic drive currents in respiratory PBC neurons. The data demonstrate that augmentation of the respiratory output is due to direct enhancement of central respiratory network activity and increase of synaptic drive of hypoglossal motoneurons in juvenile, but not neonatal, animals. This indicates a developmental change in the efficacy of aminophylline to reinforce central respiratory network activity. Therefore, we believe that the variable success in treating respiratory disturbances in premature infants reflects maturational changes in the expression of receptors and/or intracellular signal pathways in the central respiratory network.

Effects of CO2 rebreathing on pulmonary mechanics in premature infants

1991 ◽  
Vol 70 (6) ◽  
pp. 2582-2586 ◽  
Author(s):  
M. J. Miller ◽  
J. M. DiFiore ◽  
K. P. Strohl ◽  
W. A. Carlo ◽  
R. J. Martin
Keyword(s):  
Premature Infants ◽  
Supraglottic Airway ◽  
Lower Airway ◽  
Pulmonary Mechanics ◽  
Respiratory Drive ◽  
Quiet Sleep ◽  
Co2 Rebreathing ◽  
End Tidal ◽  
Gestational Age At Birth ◽  
Pressure Catheter

The effects of hypercapnia produced by CO2 rebreathing on total pulmonary, supraglottic, and lower airway (larynx and lungs) resistance were determined in eight premature infants [gestational age at birth 32 +/- 3 (SE) wk, weight at study 1,950 +/- 150 g]. Nasal airflow was measured with a mask pneumotachograph, and pressures in the esophagus and oropharynx were measured with a fluid-filled or 5-Fr Millar pressure catheter. Trials of hyperoxic (40% inspired O2 fraction) CO2 rebreathing were performed during quiet sleep. Total pulmonary resistance decreased progressively as end-tidal PCO2 (PETCO2) increased from 63 +/- 23 to 23 +/- 15 cmH2O.l-1.s in inspiration and from 115 +/- 82 to 42 +/- 27 cmH2O.l-1.s in expiration between room air (PETCO2 37 Torr) and PETCO2 of 55 Torr (P less than 0.05). Lower airway resistance (larynx and lungs) also decreased from 52 +/- 22 to 18 +/- 14 cmH2O.l-1.s in inspiration and from 88 +/- 45 to 30 +/- 22 cmH2O.l-1.s in expiration between PETCO2 of 37 and 55 Torr, respectively (P less than 0.05). Resistance of the supraglottic airway also decreased during inspiration from 7.2 +/- 2.5 to 3.6 +/- 2.5 cmH2O.l-1.s and in expiration from 7.6 +/- 3.3 to 5.3 +/- 4.7 cmH2O.l-1.s at PETCO2 of 37 and 55 Torr (P less than 0.05). The decrease in resistance that occurs within the airway in response to inhaled CO2 may permit greater airflow at any level of respiratory drive, thereby improving the infant's response to CO2.

The Excavations at Ur, 1924–1925

1925 ◽  
Vol 5 (4) ◽  
pp. 347-402 ◽  
Author(s):  
C. Leonard Woolley
Keyword(s):  
Preliminary Report ◽  
British Museum ◽  
University Of Pennsylvania ◽  
Card Index ◽  
University Museum ◽  
The Cost ◽  
The University ◽  
First Time

The Joint Expedition of the British Museum and of the Museum of the University of Pennsylvania restarted its excavations at Ur on 1st November 1924 and closed down on 28th February 1925 after a most successful season. For the epigraphical side of the work I had associated with me this year Dr. L. Legrain, of the University Museum, to whose help I owe much more than I can express: even in this preliminary report it will be clear how greatly our discoveries gained in interest and value from his study of the inscriptions. Mr. J. Linnell, who was in the field for the first time, assisted on the general archaeological side and kept the card index of objects. Unfortunately there was no architect on the staff, and we had to make what shift we could without, in a campaign peculiarly rich in architectural results; all the time I had reason to regret the loss of Mr. F. G. Newton, whose skill and experience had proved invaluable in former years. The main reason for the lack of an architect was shortness of funds: the British Museum was unable to provide from its own resources its due half of the cost of the Expedition, and we could not have taken the field at all but for the generous help given by friends in London; and even so I should have been obliged to bring the season to a premature end in January had not the British residents in Iraq come forward with subscriptions for the British Museum's side of the work which, met by Philadelphia with an equal sum, enabled me to carry on for another month. To all these I wish to acknowledge my gratitude.

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