scholarly journals Eupnea, tachypnea, and autoresuscitation in a closed-loop respiratory control model

2017 ◽  
Vol 118 (4) ◽  
pp. 2194-2215 ◽  
Author(s):  
Casey O. Diekman ◽  
Peter J. Thomas ◽  
Christopher G. Wilson
Keyword(s):  
Central Pattern Generator ◽  
Closed Loop ◽  
Minute Ventilation ◽  
Respiratory Control ◽  
Pattern Generator ◽  
Control Model ◽  
Open Loop ◽  
Blood Oxygen ◽  
Rhythm Generation ◽  
Metabolic Demand

How sensory information influences the dynamics of rhythm generation varies across systems, and general principles for understanding this aspect of motor control are lacking. Determining the origin of respiratory rhythm generation is challenging because the mechanisms in a central circuit considered in isolation may be different from those in the intact organism. We analyze a closed-loop respiratory control model incorporating a central pattern generator (CPG), the Butera-Rinzel-Smith (BRS) model, together with lung mechanics, oxygen handling, and chemosensory components. We show that 1) embedding the BRS model neuron in a control loop creates a bistable system; 2) although closed-loop and open-loop (isolated) CPG systems both support eupnea-like bursting activity, they do so via distinct mechanisms; 3) chemosensory feedback in the closed loop improves robustness to variable metabolic demand; 4) the BRS model conductances provide an autoresuscitation mechanism for recovery from transient interruption of chemosensory feedback; and 5) the in vitro brain stem CPG slice responds to hypoxia with transient bursting that is qualitatively similar to in silico autoresuscitation. Bistability of bursting and tonic spiking in the closed-loop system corresponds to coexistence of eupnea-like breathing, with normal minute ventilation and blood oxygen level and a tachypnea-like state, with pathologically reduced minute ventilation and critically low blood oxygen. Disruption of the normal breathing rhythm, through either imposition of hypoxia or interruption of chemosensory feedback, can push the system from the eupneic state into the tachypneic state. We use geometric singular perturbation theory to analyze the system dynamics at the boundary separating eupnea-like and tachypnea-like outcomes. NEW & NOTEWORTHY A common challenge facing rhythmic biological processes is the adaptive regulation of central pattern generator (CPG) activity in response to sensory feedback. We apply dynamical systems tools to understand several properties of a closed-loop respiratory control model, including the coexistence of normal and pathological breathing, robustness to changes in metabolic demand, spontaneous autoresuscitation in response to hypoxia, and the distinct mechanisms that underlie rhythmogenesis in the intact control circuit vs. the isolated, open-loop CPG.

Use of a Central Pattern Generator for Control of a Muscle-Actuated Simulation of Pedaling

2009 ◽  
Author(s):  
Martin Schultze ◽  
Darryl G. Thelen
Keyword(s):  
Central Pattern Generator ◽  
Large Scale ◽  
Pattern Generator ◽  
Open Loop ◽  
Dynamic Simulations ◽  
Short Time ◽  
Time Frames ◽  
Large Scale Simulations ◽  
Clinical Problems

Muscle actuated forward dynamic simulations have provided tremendous insights into the mechanics of locomotion. However, the controllers used for large scale simulations have often been open-loop, with the muscle excitations prescribed as a function of time [1]. Due to the inherently unstable nature of bipedal movement, this means that perturbation-type analyses are often limited to short time frames after the perturbation is introduced [2]. However for many clinical problems, it would be desirable to predict how periodic locomotion reestablishes following a change to the system or perturbation from the environment.

scholarly journals Behavioural system identification of visual flight speed control in Drosophila melanogaster

2010 ◽  
Vol 8 (55) ◽  
pp. 171-185 ◽  
Author(s):  
Nicola Rohrseitz ◽  
Steven N. Fry
Keyword(s):  
System Identification ◽  
Flight Control ◽  
Closed Loop ◽  
Speed Control ◽  
Control Model ◽  
Open Loop ◽  
Flight Speed ◽  
Level Control ◽  
Wide Range ◽  
Sensory Motor

Behavioural control in many animals involves complex mechanisms with intricate sensory-motor feedback loops. Modelling allows functional aspects to be captured without relying on a description of the underlying complex, and often unknown, mechanisms. A wide range of engineering techniques are available for modelling, but their ability to describe time-continuous processes is rarely exploited to describe sensory-motor control mechanisms in biological systems. We performed a system identification of visual flight speed control in the fruitfly Drosophila , based on an extensive dataset of open-loop responses previously measured under free flight conditions. We identified a second-order under-damped control model with just six free parameters that well describes both the transient and steady-state characteristics of the open-loop data. We then used the identified control model to predict flight speed responses after a visual perturbation under closed-loop conditions and validated the model with behavioural measurements performed in free-flying flies under the same closed-loop conditions. Our system identification of the fruitfly's flight speed response uncovers the high-level control strategy of a fundamental flight control reflex without depending on assumptions about the underlying physiological mechanisms. The results are relevant for future investigations of the underlying neuromotor processing mechanisms, as well as for the design of biomimetic robots, such as micro-air vehicles.

Glutamatergic N2v Cells Are Central Pattern Generator Interneurons of the Lymnaea Feeding System: New Model for Rhythm Generation

1997 ◽  
Vol 78 (6) ◽  
pp. 3396-3407 ◽  
Author(s):  
M. J. Brierley ◽  
M. S. Yeoman ◽  
P. R. Benjamin
Keyword(s):  
Central Pattern Generator ◽  
Synaptic Connection ◽  
Giant Cells ◽  
Pattern Generator ◽  
Synaptic Connections ◽  
Rhythm Generation ◽  
Feeding System ◽  
New Model ◽  
Feeding Cycle ◽  
Protraction Phase

Brierley, M. J., M. S. Yeoman, and P. R. Benjamin. Glutamatergic N2v cells are central pattern generator interneurons of the Lymnaea feeding system: new model for rhythm generation. J. Neurophysiol. 78: 3396–3407, 1997. We aimed to show that the paired N2v (N2 ventral) plateauing cells of the buccal ganglia are important central pattern generator (CPG) interneurons of the Lymnaea feeding system. N2v plateauing is phase-locked to the rest of the CPG network in a slow oscillator (SO)-driven fictive feeding rhythm. The phase of the rhythm is reset by artificially evoked N2v bursts, a characteristic of CPG neurons. N2v cells have extensive input and output synaptic connections with the rest of the CPG network and the modulatory SO cell and cerebral giant cells (CGCs). Synaptic input from the protraction phase interneurons N1M (excitatory), N1L (inhibitory), and SO (inhibitory-excitatory) are likely to contribute to a ramp-shaped prepotential that triggers the N2v plateau. The prepotential has a highly complex waveform due to progressive changes in the amplitude of the component synaptic potentials. Most significant is the facilitation of the excitatory component of the SO → N2v monosynaptic connection. None of the other CPG interneurons has the appropriate input synaptic connections to terminate the N2v plateaus. The modulatory function of acetylcholine (ACh), the transmitter of the SO and N1M/N1Ls, was examined. Focal application of ACh (50-ms pulses) onto the N2v cells reproduced the SO → N2v biphasic synaptic response but also induced long-term plateauing (20–60 s). N2d cells show no endogenous ability to plateau, but this can be induced by focal applications of ACh. The N2v cells inhibit the N3 tonic (N3t) but not the N3 phasic (N3p) CPG interneurons. The N2v → N3t inhibitory synaptic connection is important in timing N3t activity. The N3t cells recover from this inhibition and fire during the swallow phase of the feeding pattern. Feedback N2v inhibition to the SO, N1L protraction phase interneurons prevents them firing during the retraction phase of the feeding cycle. The N2v → N1M synaptic connection was weak and only found in 50% of preparations. A weak N2v → CGC inhibitory connection prevents the CGCs firing during the rasp (N2) phase of the feeding cycle. These data allowed a new model for the Lymnaea feeding CPG to be proposed. This emphasizes that each of the six types of CPG interneuron has a unique set of synaptic connections, all of which contribute to the generation of a full CPG pattern.

Endogenous and Network Properties of LymnaeaFeeding Central Pattern Generator Interneurons

2002 ◽  
Vol 88 (4) ◽  
pp. 1569-1583 ◽  
Author(s):  
Volko A. Straub ◽  
Kevin Staras ◽  
György Kemenes ◽  
Paul R. Benjamin
Keyword(s):  
Central Pattern Generator ◽  
Activity Patterns ◽  
Pattern Generator ◽  
Pattern Generation ◽  
Detailed Knowledge ◽  
Rhythm Generation ◽  
Cell Type ◽  
Intrinsic Properties ◽  
Plateau Potential ◽  
Network Properties

Understanding central pattern generator (CPG) circuits requires a detailed knowledge of the intrinsic cellular properties of the constituent neurons. These properties are poorly understood in most CPGs because of the complexity resulting from interactions with other neurons of the circuit. This is also the case in the feeding network of the snail, Lymnaea, one of the best-characterized CPG networks. We addressed this problem by isolating the interneurons comprising the feeding CPG in cell culture, which enabled us to study their basic intrinsic electrical and pharmacological cellular properties without interference from other network components. These results were then related to the activity patterns of the neurons in the intact feeding network. The most striking finding was the intrinsic generation of plateau potentials by medial N1 (N1M) interneurons. This property is probably critical for rhythm generation in the whole feeding circuit because the N1M interneurons are known to play a pivotal role in the initiation of feeding cycles in response to food. Plateau potential generation in another cell type, the ventral N2 (N2v), appeared to be conditional on the presence of acetylcholine. Examination of the other isolated feeding CPG interneurons [lateral N1 (N1L), dorsal N2 (N2d), phasic N3 (N3p)] and the modulatory slow oscillator (SO) revealed no significant intrinsic properties in relation to pattern generation. Instead, their firing patterns in the circuit appear to be determined largely by cholinergic and glutamatergic synaptic inputs from other CPG interneurons, which were mimicked in culture by application of these transmitters. This is an example of a CPG system where the initiation of each cycle appears to be determined by the intrinsic properties of a key interneuron, N1M, but most other features of the rhythm are probably determined by network interactions.

Respiratory Central Pattern Generator: Microcircuit Generation of the Rhythms and Patterns of Breathing

2017 ◽  
pp. 475-488
Author(s):  
Kaiwen Kam ◽  
Jack L. Feldman
Keyword(s):  
Central Pattern Generator ◽  
Neurodegenerative Disorders ◽  
Neural Control ◽  
Motor Behavior ◽  
Pattern Generator ◽  
Control Of Breathing ◽  
Facial Nucleus ◽  
Metabolic Demand ◽  
Previous Edition ◽  
Neural Control Of Breathing

Breathing is a vital rhythmic motor behavior that mediates gas exchange to support metabolism and regulate pH. All mammals must breathe continuously and reliably from birth and modulate their breathing throughout life in response to changes in metabolic demand and environmental stimuli. A number of congenital and neurodegenerative disorders affect the neural control of breathing in humans and lead to serious adverse health consequences, even death. Since the previous edition of this book, there have been considerable advances in our understanding of the breathing central pattern generator (CPG). This chapter focuses on the neural microcircuit within the preBötzinger Complex (preBötC); a second oscillator near the facial nucleus that appears to generate active expiration; and the microcircuit for sighing.

Ventilatory response of the cat to hypoxia in sleep and wakefulness

2003 ◽  
Vol 95 (2) ◽  
pp. 545-554 ◽  
Author(s):  
Andrew T. Lovering ◽  
Witali L. Dunin-Barkowski ◽  
Edward H. Vidruk ◽  
John M. Orem
Keyword(s):  
Tidal Volume ◽  
Central Pattern Generator ◽  
Eye Movement ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Pattern Generator ◽  
Rapid Eye Movement Sleep ◽  
Inspiratory Activity ◽  
Adult Cat ◽  
Ventilatory Response To Hypoxia

This study characterized ventilation, the airflow waveform, and diaphragmatic activity in response to hypoxia in the intact adult cat during sleep and wakefulness. Exposure to hypoxia for up to 3 h caused sustained hyperventilation during both wakefulness and sleep. Hyperventilation resulted from significant increases in minute ventilation due to increases in both tidal volume and frequency. Diaphragmatic activity changed significantly from augmenting activity with little postinspiratory-inspiratory activity (PIIA) in normoxia to augmenting activity with increased PIIA in hypoxia. The increase in PIIA was least in rapid eye movement sleep. These changes in diaphragmatic activity were associated with changes in airflow waveforms in inspiration and expiration. We conclude that the ventilatory response to hypoxia involves a change in the output of the central pattern generator and that the change is dependent in part on the state of consciousness.

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