Circuit Models for Robust, Adaptive Neural Control

Understanding a nematode's simple circuit could provide a foundation for understanding much more complex behaviors.

Air Force Research Laboratory, Arlington, Virginia

This project seeks to reproduce the neural circuits used by the nematode Caenorhabditis elegans for locomotion. Caenorhabditis elegans is a small (∼1.2 millimeter) nematode found in rotting fruit in many parts of the world. It feeds on bacteria and is neither parasitic nor pathogenic. Although capable of sexual reproduction, most laboratory strains reproduce primarily as self-fertilizing hermaphrodites, with each adult hermaphrodite producing approximately 300 progeny (Figure 1).

C. elegans is a very simple organism, with only 959 somatic cells in the adult hermaphrodite. Although the total number of cells is small, they are differentiated into the standard array of tissues: 302 neurons, 95 body muscle cells, 32 gut cells, etc. In addition, the position, morphology, and lineage of each cell are reproducible from animal to animal. Because of the small size of the animal, the relatively small number of neurons, and the reproducible nature of the nervous system, it has been possible to provide an almost-complete synaptic connectivity map of the adult hermaphrodite nervous system (Figure 2).