Optical voltage imaging in neurons: moving from technology development to practical tool

A central goal in neuroscience is to determine how the brain’s neuronal circuits generate perception, cognition and emotions and how these lead to appropriate behavioural actions. A methodological platform based on genetically encoded voltage indicators (GEVIs) that enables the monitoring of large-scale circuit dynamics has brought us closer to this ambitious goal. This Review provides an update on the current state of the art and the prospects of emerging optical GEVI imaging technologies. Genetically encoded voltage indicators (GEVIs) are emerging tools to elucidate the inner workings of the brain. In this Review, Knopfel and Song outline the potentials of GEVI imaging based on recent neurotechnological and conceptual advances in the brain sciences.