20xUAS sequences regulate expression of jGCaMP8m that is tagged at the N-terminal end (via a GGGGSGGGGS flexible linker) with the Syt1 coding sequence (this targets the protein to the synapse) and at the C-terminal end (via a GGSSSGGSSS flexible linker) with mCyRFP3. The coding sequence is codon optimized for Drosophila.