Some details of signal propagation in the nervous system of C. elegans

Abstract

Among the organisms most widely used to study fundamental mechanisms of nervous system functioning, Caenorhabditis elegans is unique due to exceptionally small number of its neurons. Over a period of 25 years, it remains the only organism with a known connectome, a description of all neurons and interneuronal connections. However, this information appeared to be insufficient for deciphering the mechanisms underlying the operation of even such a small nervous system. The following years were devoted to both experimental research that significantly supplemented the obtained data and the development of computational models consolidating individual fragments of the nervous, sensory, and muscular systems. Since 2005 there have been attempts to create a virtual copy of C. elegans, a sophisticated computer model that combines the nervous, sensory, and muscle systems, the body, and part of the environment. Despite some progress in this direction, the results have not brought the researchers to a solution to the problem but instead have shed light on its actual complexity. In this paper, we examine a number of problems faced by the researcher who set out to create a biologically based model of the nervous system of C. elegans on the example of a simple nerve circuit associated with the response to the mechanosensory signal.