Ca2+ signaling via the neuronal calcium sensor-1 regulates associative learning and memory in C-elegans

On a radial temperature gradient, C. elegans worms migrate, after condition ing with food, toward their cultivation temperature and move along this iso therm. This experience-dependent behavior is called isothermal tracking (IT ). Here we show that the neuron-specific calcium sensor-1 (NCS-1) is essent ial for optimal IT. ncs-1 knockout animals show major defects in IT behavio r, although their chemotactic, locomotor, and thermal avoidance behaviors a re normal. The knockout phenotype can be rescued by reintroducing wildtype NCS-1 into the AIY interneuron, a key component of the thermotaxis network. A loss-of-function form of NCS-1 incapable of binding calcium does not res tore IT, whereas NCS-1 overexpression enhances IT performance levels, accel erates learning (faster acquisition), and produces a memory with slower ext inction. Thus, proper calcium signaling via NCS-1 defines a novel pathway e ssential for associative learning and memory.