The role of neuropeptides in learning and memory in Caenorhabditis elegans

•C. elegans is an ideal model organism for genetic studies of learning and memory.•Delineate neuropeptides and neural circuits involved in learning and memory.•Insulin-like signaling is important where feeding state is the unconditioned stimulus.•FLP-20 mediates memory of habituation 12-hours after massed training.•Potential role for uncharacterized neuropeptide receptors in behavioral plasticity.

C. elegans is an ideal system for behavioral genetic analysis of learning and memory. Recently a number of papers have highlighted the importance of neuropeptide signaling in this behavioral plasticity. Neuropeptide signaling has been found to modulate the worm's learned preference for smells, tastes, and temperatures associated with feeding state, as well as their response following prolonged exposure to chemo- or mechano-sensory stimuli in non-associative learning paradigms. Depending on the assay, sensory neurons and interneurons have been shown to be both the source of the neuropeptides and the site of action. Most neuropeptide receptors are orphaned and functionally uncharacterized, but are expected to emerge as major modulators of behavior.