Optical induction of auditory perception via cochlear stimulation in Mongolian gerbils without genetic modification

Whether auditory perception can be non-invasively induced by optical stimulation without genetic modification remains an open question in sensory neuroscience and neuroprostheses. This study presents the first demonstration that transtympanic infrared laser stimulation of the cochlea evokes reliable auditory-guided behavior in awake animals. Mongolian gerbils ( Meriones unguiculatus ) were subjected to classical conditioning where a reward water delivery was predicted by either cochlear laser stimulation or sound stimulus. Laser-conditioned animals successfully learned licking behavior, with conditioned responses and behavioral properties comparable to auditory-conditioned animals. The laser-evoked response was significantly inhibited by auditory masking, and auditory-conditioned animals demonstrated stimulus generalization to laser stimulation. These findings provide behavioral-level evidence that transtympanic infrared laser stimulation can evoke an auditory percept. Our work establishes a foundation for exploring contactless optical stimulation as a non-invasive strategy for engaging the auditory periphery and informs future development of optical approaches to auditory prosthetic technologies.