Although animals receive various sensory stimuli, they typically only execute one behavior at a time. However, the neural circuit behind behavior selection is unknown. Here we use Drosophila fly grooming to address this question. When flies are fully immersed in dust, they follow a stereotypical cleaning sequence from anterior to posterior grooming, but they cannot execute multiple cleaning behaviors simultaneously. This mutual exclusivity is necessary to prevent them from losing balance or getting injured. We used optogenetic screening to identify a group of neurons titled R81C11 that when activated induce front leg rubbing in undusted flies. In contrast, when these neurons are activated in decapitated flies they simultaneously induce front leg rubbing and back leg rubbing, overriding mutual exclusion. Anatomical image shows R81C11 contains neurons in both the brain and the ventral nerve cord (VNC). After comparing behavior data from intact and decapitated flies, we hypothesized that the subset of R81C11 neurons in VNC are able to simultaneously activate both behaviors, but signals from the brain regulate mutual exclusion. Furthermore, anatomical data shows that the neurites of VNC R81C11 neurons and axon terminals of mechanosensory bristle neurons overlap. This implies that VNC R81C11 neurons might communicate with mechanosensory bristle neurons which are the main sensilla for dust sensitivity. We intend to use genetic tools to extract a smaller subset of neurons that can induce simultaneous grooming, and to map upstream and downstream targets of these neurons. We aim to use these results to elucidate the neural mechanism of mutual exclusion.