title: Multivariable harmonic balance analysis of the neuronal oscillator for leech swimming.
abstract: Biological systems, and particularly neuronal circuits, embody a very high level of complexity. Mathematical modeling is therefore essential for understanding how large sets of neurons with complex multiple interconnections work as a functional system. With the increase in computing power, it is now possible to numerically integrate a model with many variables to simulate behavior. However, such analysis can be time-consuming and may not reveal the mechanisms underlying the observed phenomena. An alternative, complementary approach is mathematical analysis, which can demonstrate direct and explicit relationships between a property of interest and system parameters. This paper introduces a mathematical tool for analyzing neuronal oscillator circuits based on multivariable harmonic balance (MHB). The tool is applied to a model of the central pattern generator (CPG) for leech swimming, which comprises a chain of weakly coupled segmental oscillators. The results demonstrate the effectiveness of the MHB method and provide analytical explanations for some CPG properties. In particular, the intersegmental phase lag is estimated to be the sum of a nominal value and a perturbation, where the former depends on the structure and span of the neuronal connections and the latter is roughly proportional to the period gradient, communication delay, and the reciprocal of the intersegmental coupling strength.
authors.affiliation: School of Electrical Engineering and Computer Science, The University of Newcastle, Callaghan, New South Wales 2308, Australia. zhiyong.chen@newcastle.edu.au
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.forename: W Otto
authors.initials: WO
authors.lastname: Friesen
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Iwasaki
mesh_terms: D000465:Algorithms; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001683:Biological Clocks / Q000502:physiology*; D003198:Computer Simulation; D007865:Leeches / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D008959:Models, Neurological; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D017711:Nonlinear Dynamics; D013550:Swimming / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D013997:Time Factors