The circadian clock allows organisms to synchronize their physiology and behavior to the daily environmental changes caused by the rotation of the Earth. Key clock neurons in the circadian timekeeping network of the Drosophila brain display daily rhythms in morphology, and such remodeling has long been considered a clock output mechanism. In this talk, I will present our work describing how specific abrogation of the sites of daily neuronal remodeling, remarkably, has no measurable effects on circadian timekeeping or on any of the major output functions of the clock neuron network. Rather, the loss of these sites of plasticity impairs input pathways and affects the animal’s ability to synchronize their circadian clock to environmental time-cues. Based on these surprising results we propose an alternative model: structural plasticity in critical circadian clock neurons is the basis for proper integration of environmental time-cues and the resetting of the circadian clock.
host: Gabrielle Gutierrez