Fluorescent genetically encoded voltage indicators (GEVIs) are developed to monitor neural activity with single-neuron resolution, across large populations or in multiple brain areas, during behavior. Different indicators with variable spectral characteristics can be combined with other activity indicators or optogenetic tools for control of neuronal activity. With optimal brightness, photostability and low cytotoxicity of the indicator, these tools facilitate detection of various signals (subthreshold and suprathreshold events), depending on size, speed and linearity of voltage-dependent fluorescence intensity changes. The table below lists transgenes expressing GEVIs with protein-based fluorophores and chemigenetic Voltron that binds to synthetic fluorophore dye.