Several alternative models have been used to create new studies on central nervous system (CNS) function. The benefits associated with these alternative approaches are time efficiency, reduced manpower, cost-effectiveness, and avoidance of ethical concerns on the use of higher vertebrates. In this regard, Caenorhabditis elegans (C. elegans), a small, free-living, soil nematode which uses bacteria as a food source, is being used to complement traditional experiments. Studies on worm genomes add new insights into the mechanisms of several neurological disorders and neuronal regeneration. Strains can be genetically modified to express fluorescent reporters, allowing one to follow relevant regulatory pathways, visualize different neuronal lineages as well as morphology alterations. One key advantage of studies with C. elegans is that a functional synapse can be studied inside a living organism and an immediate behavioral response profile can be observed. Neurotoxicology studies using C. elegans allow the discovery of a collection of genes and molecular targets involved in neurodegeneration and other neuronal alterations following toxicological insult. Here we provide a synopsis of the findings on the cholinergic and dopaminergic systems of the CNS, using C. elegans as an animal model.