RI: Small: BCSP: The Whole Worm: A Brain-Body-Environment Model of Nematode Chemotaxis

Indiana University, Bloomington IN

Investigators

Abstract

The overall goal of this work is to construct, analyze and experimentally test a brain-body-environment model of orientation in an invertebrate. Even relatively simple animals exhibit a remarkable combination of flexibility and robustness to their behavior that would be extremely useful to the design of artificial systems. How do animals achieve this difficult balance? Understanding how animals operate as integrated wholes requires building brain-body-environment models of complete animals. This in turn requires an animal system for which detailed behavioral, biomechanical, and neuronal information is available. In this regard, knowledge of the behavior, anatomy, genetics, development and neural connectivity of the nematode worm C. elegans is perhaps the most complete of any animal, with significant progress now also being made on the electrophysiology of its nervous system. Success also requires a modeling methodology that can work cooperatively with experimental methods throughout the project lifecycle and that can provide a theoretical framework for interpreting the integrated functioning of the system. In order to demonstrate the feasibility of whole-animal modeling, this proposal describes a project to construct and analyze an integrated brain-body-environment model of C. elegans klinotaxis, a form of salt chemotaxis in which changes in direction are oriented towards the source through gradual continual adjustments. The approach described here combines connectome data-mining and a novel bracketing methodology, parameter optimization and clustering techniques for working with populations of models, and dynamical and information-theoretic analysis of representative motifs with behavioral manipulations, neuronal ablation and photo-stimulation, and electrophysiological studies on the biological system by an experimental colleague.