Abstract

One of the most fascinating properties of the brain is its ability to translate one sensory stimulus into distinct, sometimes opposite, behavioural outputs. This plasticity is what enables animals to learn and to couple behaviour to their ever-changing needs. I will present the work that we carry out in my lab, where we use the C. elegans male to identify the molecular and cellular mechanisms that allow hard-wired circuits to generate flexible behavior. We have identified secretin neuropeptide signaling as a conserved mechanism for the generation of behavioural states of arousal and innate drives. PDF modulates food sensory perception at the circuit level driving mate-deprived males to explore away from food and in search of mates. More recently, we have found a developmental mechanism for neural circuit remodeling which couples chemotactic responses to new reproductive priorities. We find that, during sexual maturation, differentiated, functional glial cells re-enter the cell cycle to produce a sex-specific class of interneurons. These interneurons are required for integration of rewarding mating experiences during associative learning leading males to switch their behavioural responses to odours and tastants from repulsion to attraction.