Circadian regulation of synaptic output at a central oscillator network across scales using correlative fluorescence functional imaging, X-R

Animals adapt their behaviour across the day producing circadian rhythms. The physiological basis behind these rhythms have been extensively characterized in the fruit fly, where a network of ~150 neurons in its brain regulates the behavioural entrainment to the time of the day. To characterize the key peptidergic neurons from this central oscillatory network, we propose to interrogate in a correlated fashion on the same samples: 1) structural changes in the axon terminal arborizations involving the assembly and disassembly of synapses; 2) changes in the activity patterns reaching the synapses to trigger neurotransmitter release and 3) changes in synaptic vesicle distribution and abundance, across the time of the day. We will establish and demonstrate a correlative imaging workflow involving functional imaging of neuronal activity reaching the output synapses, X-ray tomography of sLNv fine morphology utilizing the ID16A beamline, and FIB-SEM interrogation of synaptic vesicles.