‘Circuits of sense and sensibility’
Sometimes when we eat something that makes us sick, we lose our craving for that food forever. C. elegans feels our pain, and a Harvard biology professor has used that fact to map for the first time the complete picture of a neural network involved in learned olfactory behavior in an animal. C. elegans is a tiny roundworm just 1 millimeter long, small enough to enjoy a meal of bacteria now and then. But when it eats bacteria that make it sick, it learns to avoid them. Harvard Assistant Professor of Biology Yun Zhang led a team of researchers on an effort to train thousands of roundworms in her lab to avoid pathogenic bacteria, Pseudomonas aeruginosa, that made them sick. In collaboration with Physics Professor Aravinthan Samuel’s lab, researchers in the Zhang lab then traced the neural pathways used in both untrained and trained worms to understand the changes that made them...