CONICET | Buscador de Institutos y Recursos Humanos

In our laboratory we are interested in understanding the relevance of specific neuronal circuits in the circadian control of behavior in Drosophila. We have previously shown that sLNvs neurons, a circuit key to control rest-activity cycles in Drosophila, undergoes circadian remodeling of its axonal projections, and we have put forward the hypothesis that this structural plasticity provides the substrate for the circadian control of activity and connectivity of the PDF circuit. Here we show that this remodeling implies daily changes in presynaptic markers of active zones, opening the possibility that the connectivity is indeed changing daily. By expressing two complementary fragments of GFP tethered to synaptic membranes, we revealed that PDF axons contact different synaptic partners along the day, extending the impact of core pacemaker neurons to circuits outside of the circadian network. We propose that this plasticity is capable of affecting the synaptic output in a circadian fashion, by means of these structural changes. In order to test this hypothesis we are currently performing live whole brain optical imaging experiments to test if the putative synaptic partnerships identified through GRASP are indeed functional. To answer this question we will use two binary systems of expression such as GAL4/UAS and lexA/lexAop that will allow us to specifically activate the PDF neurons, while concomitantly expressing a reporter of activity on the putative post synaptic partners.