The broad aim for this project is to enhance the understanding of biological information processing mechanisms. The immediate goals are to uncover the fundamental roles of sensory feedback mechanisms in the neuronal control of animal locomotion and to establish mathematical models that predict the dynamical behavior of and supply missing information about the biological system. More specifically, the aims are to I) perform biophysical and physiological experiments on leech preparations to collect neuronal and mechanical input/output data needed for quantitative models, II) develop a mathematical model of the neuronal control system for leech swimming that includes sensory feedback, III) predict the effects of sensory feedback through numerical simulations of the model, and IV) test these predictions through physiological experiments on leech preparations. ? ? This project employs the Lur'e model for neuronal dynamics, recently developed by the Pl, as a basis for the modeling of neurodynamic feedback control system of leech swimming. The class of Lur'e systems has been extensively studied in the systems and control discipline and thus a variety of mathematical analysis tools are available. The project develops dynamical models (differential equations) of the leech locomotion control system, consisting of the central oscillator, muscle actuation by motoneurons, body-fluid interactions, and sensory feedback from stretch receptors, through parameter identifications based on experimental observations. Physiological experiments will be conducted on dissected and intact leech preparations to obtain explicit values for model parameters and to test hypotheses generated by experiments performed on the model. ? ? The collaborative engineering--neurophysiological research proposed here is part of a broad effort to discover general principles for the neuronal control of animal movements. Because of the functional similarity, insights gained from the proposed research on leech swimming can be expected to increase our understanding of the neuronal control of rhythmic movements generally. Potential applications of the knowledge to be generated include insights into the cause of walking disability and development of rehabilitation methodologies. ? ?
| Iwasaki, Tetsuya; Chen, Jun; Friesen, W Otto (2014) Biological clockwork underlying adaptive rhythmic movements. Proc Natl Acad Sci U S A 111:978-83 |
| Chen, Jun; Friesen, W Otto; Iwasaki, Tetsuya (2012) Mechanisms underlying rhythmic locomotion: interactions between activation, tension and body curvature waves. J Exp Biol 215:211-9 |
| Chen, J; Friesen, W O; Iwasaki, T (2011) Mechanisms underlying rhythmic locomotion: body-fluid interaction in undulatory swimming. J Exp Biol 214:561-74 |
| Chen, Jun; Tian, Jianghong; Iwasaki, Tetsuya et al. (2011) Mechanisms underlying rhythmic locomotion: dynamics of muscle activation. J Exp Biol 214:1955-64 |
| Tian, Jianghong; Iwasaki, Tetsuya; Friesen, Wolfgang Otto (2010) Analysis of impulse adaptation in motoneurons. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 196:123-36 |
| Iwasaki, Tetsuya (2008) Multivariable Harmonic Balance for Central Pattern Generators. Automatica (Oxf) 44:3061-3069 |
| Chen, Zhiyong; Zheng, Min; Friesen, W Otto et al. (2008) Multivariable harmonic balance analysis of the neuronal oscillator for leech swimming. J Comput Neurosci 25:583-606 |
| Futakata, Y; Iwasaki, T (2008) Formal analysis of resonance entrainment by central pattern generator. J Math Biol 57:183-207 |
| Friesen, W Otto; Kristan, William B (2007) Leech locomotion: swimming, crawling, and decisions. Curr Opin Neurobiol 17:704-11 |
| Tian, Jianghong; Iwasaki, Tetsuya; Friesen, W Otto (2007) Muscle function in animal movement: passive mechanical properties of leech muscle. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 193:1205-19 |
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