Modeling Chemotaxis in the Nematode C. elegans

To elucidate the neural mechanisms of chemotaxis in the nematode C. elegans, we constructed a model based on the anatomically defined neural circuitry associated with identified chemosensory neurons. The model combines the temporal derivative of chemosensory input with an internal representation of behavioral state to produce a duty-cycle controller of head angle during swimming movements. The model reproduces observed chemotactic behavior and suggests that separate control circuitry is required when moving up as opposed to down the concentration gradient.