Optogenetics is the combination of optical tools to monitor (i.e. “reporters”) or interfere (i.e. “actuators”) with neural activity, and genetic techniques to restrain the expression of these reporters and actuators in the neuronal populations of interest. Such combination of optical and genetic tools, together with the emergence of new animal models such as the zebrafish larva, has proven extremely valuable is dissecting neural circuits. Optogenetics provide a new framework to address issues that are fundamentally dynamic processes, such as sensorimotor integration in the vertebrate spinal cord. By shifting from spatially targeted electrical stimulation to genetically targeted optical stimulation, optogenetic also opens new avenues for innovative neurorehabilitative strategies, in particular after spinal cord injury.