Nonlinear Dynamics of a Model of the Central Respiratory Pattern Generator

  • A. Gottschalk
  • K. A. Geitz
  • D. W. Richter
  • M. D. Ogilvie
  • A. I. Pack

Abstract

Recently, several models have computationally explored the network hypothesis of central respiratory rhythm generation.1, 2 One characteristic common to these models is the perfectly periodic nature of their outputs. This is not consistent with the impression that the respiratory rhythm is considerably more variable. This impression was recently quantified,3 and the data supports the notion that lightly anesthetized vagotomized animals exhibit rhythmic behavior consistent with perfectly periodic limit cycle oscillations. However, animals with an intact vagus consistently displayed more irregular respiratory patterns. The dynamical features of these patterns were quantitated by computing the correlation dimension of the corresponding time series.4 The vagotomized animals produced time series whose correlation dimension was equal to one, whereas the presence of an intact vagus, rather than stabilizing the rhythm, produced time series with non-integer correlation dimensions significantly greater than unity. The presence of a non-integer correlation dimension is consistent with a process exhibiting chaotic dynamics.4 Thus, the breath by breath variability in the ventilatory pattern may be explainable as a fundamental component of the process generating the respiratory rhythm, and not the product of intrinsic or extrinsic noise, or overwhelming system dimensionality. We hypothesized that our model of the central respiratory pattern generator, when appropriately modified to include vagal feedback from the pulmonary stretch receptors, would exhibit chaotic dynamics.

Keywords

Lyapunov Exponent Bifurcation Diagram Chaotic Dynamic Correlation Dimension Respiratory Rhythm 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1992

Authors and Affiliations

  • A. Gottschalk
    • 1
    • 2
  • K. A. Geitz
    • 2
  • D. W. Richter
    • 3
  • M. D. Ogilvie
    • 2
  • A. I. Pack
    • 2
  1. 1.Department of AnesthesiaHospital of the University of PennsylvaniaPhiladelphiaUSA
  2. 2.Center for Sleep and Respiratory NeurobiologyHospital of the University of PennsylvaniaPhiladelphiaUSA
  3. 3.II Department of PhysiologyUniversity of Goettingen34 GoettingenGermany

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