As a Grass fellow I will use the larva of the ascidian Ciona—an emerging system for neuroscience—to investigate the sensory systems and neuronal circuitries controlling behaviors driven by mechanical cues. I will characterize the mechanosensory cells of this animal by combining calcium imaging, cell ablation and cell inactivation techniques. The reduced number of neurons in Ciona and its fully mapped synaptic connectome will also allow me during the program to functionally dissect the downstream circuitries. By working on an ascidian—the closest relatives of the vertebrates—I eventually aim to gain insights into the function and evolution of the vertebrate nervous system. By studying Ciona sensory-motor circuitries with modern approaches I may also contribute to a more widespread use of this and similar systems for neuroscience.