Project Summary Communication between animals relies on sensory reception, transduction, and processing. Loss of hearing, smell or taste alters social as well as environmental interactions, and adversely affects animal survival and fitness. Primary cilia are present on all sensory neurons, including on olfactory neurons in the vertebrate nasal epithelium. These cilia house all olfactory signaling molecules and are thus critical for sensory reception. The organization of neurons and their processes within neuropils is known to be important for neuron function, but the organization of cilia within sense organs is poorly studied. In the mouse olfactory epithelium, olfactory sensory neurons (OSNs) in highly stimulated regions contain longer cilia, suggesting that ciliary patterns may have functional consequences. The cilia of eight chemosensory neurons of the C. elegans bilateral amphid sense organs are present within a channel formed by surrounding glia. These cilia are stereotypically arranged, giving rise to specific cilia-cilia contacts. The functions of each of these chemosensory neurons are known and can be readily assessed via imaging of stimulus-evoked behaviors and intracellular calcium dynamics. Thus, this system provides an excellent model in which to study cilia organization and its impact on chemosensory neuron functions. This proposal will investigate the molecular mechanism controlling cilia organization in a sense organ, and whether this organization or the cilia-cilia contacts that arise from it, influence chemosensory neuron functions. The results from this work will provide foundational knowledge about cilia organization and its importance in chemosensory neuron function, a largely unexplored area of chemosensory biology. The experiments described in this proposal will provide training in high-resolution microscopy and quantitative analyses of chemosensory behaviors and neuronal responses. Additionally, this proposal includes specific plans to enhance training in mentorship, scientific communication, and networking, all of which are critical skills to become an independent researcher.