Optogenetic stimulation of the auditory pathway for research and future prosthetics.

Sound is encoded by spiral ganglion neurons (SGNs) in the hearing organ, the cochlea, with great temporal, spectral and intensity resolution. When hearing fails, electric stimulation by implanted prostheses can partially restore hearing. Optical stimulation promises a fundamental advance of hearing restoration over electric prostheses since light can be conveniently focused and hence might dramatically improve frequency resolution of sound encoding. Combining optogenetic manipulation of neurons with innovative optical stimulation technology promises versatile spatiotemporal stimulation patterns in the auditory system. Therefore, using optical stimulation of SGNs also has great potential for auditory research. Here, I review recent progress in optogenetic stimulation of the auditory system and its potential for future application in research and hearing restoration.