[
East Asia Worm Meeting,
2004]
In recent years, a new approach for analyzing functional mechanism of a living organism has been proposed, in which computer simulation of a mathematical model is fully utilized ['98 H.Ohtake, '01 H.Kitano]. In this analysis using a virtual model instead of the corresponding actual organism, it is possible to change environmental conditions easily and to analyze their behavior repeatedly under the same conditions. This is not only useful to the area of biology, but also possible to be applied to the area of engineering such as establishment of a new brain-like machine based on the mechanism of living organisms. In the approach using a virtual model, analysis of simple' organisms is necessary to understand systems of higher organisms. Therefore, our group has developed computer models of two kinds of unicellular organisms, colibacilli and paramecium, based on the knowledge of both biology and engineering ['02 T.Tsuji et al. , '04 A.Hirano et al. ]. This study deals with multicellular organisms as the next step of the above-mentioned approach. Among multicellular organisms, we focus on Caenorhabditis elegans ( C. elegans ), and aim to develop a computer model of this organism based on the previous studies at the nervous level. So far, many studies of the C. elegans model have been reported [for example, '99 T.C.Ferree et al. , '01 K.Kawamura et al. ]. However, since they focused on only sensing and processing external stimuli, the locomotion which is appeared was extremely simplified. In modeling C. elegans , the motor control system with respect to locomotory responses have to be considered as well as the internal processing system. Consequently, we propose a computer model of C. elegans , which includes the nervous circuit model for processing external stimuli and the kinematic 12-link body model for locomotion control. Although the C. elegans processes many kinds of stimuli, we focus on gentle touch stimuli. In this presentation, we will explain in detail both of a nervous circuit model for touch stimuli and a kinematic model of the body. Also, some properties of our model, particularly those related to the taxis for touch stimuli, will be discussed through the simulation results.