Project Summary The goal of this equipment supplement for the parental award (R35GM119844) is to expand the capability of multiphoton imaging microscopy in the Asahina lab so that neural activities in the brain of a live fly can be monitored while the experimenter applies complex sensory stimuli and pharmacological reagents, optogenetically and thermogenetically manipulates specific neuronal population, and records behavior. To achieve the goals outlined in the parental grant, it is increasingly necessary to understand physiological dynamics of aggression-controlling circuits. To calculate relative cost and benefit of a given social behavior in a context-dependent manner, the fly brain must amplify or diminish relevant sensory information according to the animal’s nutritional and hormonal conditions, as well as the individual behavioral history unique to each individual. The functional imaging setup currently available in the recipient’s lab is inadequate to quantitatively detect context-dependent representation of sensory cues, because the outdated design of the microscopy constrains the space available near the objective lens. The proposed piece of equipment for purchase is a gantry frame with a motorized XY-stage. The simplified support structure of the frame will eliminate unnecessary space-filling parts of the microscopy that surround the objective lens, while the stage provides a mounting space sufficient for setting up multiple stimulus-delivery setups, LED, heat probe, and other devices for neuronal manipulations. These features will greatly facilitate the successful completion of the goals of the parental grant.