UAS regulatory sequences drive expression of a pseudoratiometric genetically-encoded Ca[2+] indicator that is composed of FusionRed (Ca[2+]-insensitive) fused (via a 20 residue RGSASGGGGGLVPRGSASGA linker) to GCaMP6m (Ca[2+]-sensitive). The coding sequence is tagged at the N-terminal end with a myristoylation sequence (resulting in the protein being anchored to the membrane and displayed on the intracellular side), and the Tag:HA epitope.