In vitro and in vivo characterization of improved channelrhodopsin ChRmine variants for optogenetic activation of the auditory pathway

Background Optogenetic activation of the auditory pathway using channelrhodopsins (ChR) presents a promising solution to overcome the limitations of cochlear implants imposed by the wide-spread electrical excitation of spiral ganglion neurons (SGNs). Before a clinical translation of optogenetic hearing restoration a suitable ChR variant needs to be identified. In this study, we designed and investigated improved variants of the green-light activated ChRmine for their optogenetic utility.