I am fascinated by the molecular and cellular processes that drive behavior. As such, I am tremendously interested in understanding how physiological regulators of neuronal circuit activity modulate sensory information processing and behavior. Neuropeptides are secreted signaling molecules that regulate a variety of nervous system functions to influence whole organism behavior.
Despite their physiological relevance, fundamental mechanistic questions remain unanswered about how these neuromodulators fine tune the output of cellular circuits to optimize behavioral responses. I use the experimentally accessible and genetically tractable Caenorhabditis elegans as a model system to address these questions. Worms express homologues of an arthropod peptide Pigment Dispersing Factor (PDF) and its cognate receptor, PDF Receptor (PDFR). Activation of light sensors triggers secretion of PDF and its close mammalian relative, Vasoactive Intestinal Peptide (VIP), which modulate daily locomotor rhythms in insects and mammals, respectively.
I am currently investigating the function of the worm PDF homolog in responses to light. A genetic and cellular analysis of this behavior indicates that the PDF peptide regulates the output of sensorimotor neural circuitry to modulate decision-making and navigation in the presence of light. Specifically, the results suggest that a conserved mechanistic link exists between circadian light entrainment in mammals and photophobic responses in the simpler worm, potentially providing a deeper understanding of the PDF/VIP signaling modules of other Metazoans. Generally, our studies further understanding of the molecular, cellular, and physiological mechanisms by which neuromodulators regulate behaviors.