Non-invasive optical synthetization of hearing sensation in non-genetically modified animal

Abstract

The application of infrared laser stimulation to brain-machine interfaces, such as cochlear implants, has been discussed over the last decade because the infrared laser can activate spatially selected neural populations without delivering exogenous agents to tissues. Here, this study demonstrated for the first that the laser irradiation of the peripheral sensory organ, the cochlea, can induce an unequivocal behavioral auditory response. We proved that the animals, Mongolian gerbils (Meriones unguiculatus), can be classically conditioned with a laser stimulus in a similar way to an auditory stimulus. Additionally, the auditory masking significantly inhibited the laser-conditioned response, and the auditory-conditioned animals exhibited stimulus generalization to laser stimulation. In a subsequent experiment, simultaneous presentation of auditory and laser stimulation successfully elicited nonlinear amplification in both the auditory cortical and behavioral response. These results suggest that the infrared laser irradiation to the cochlea can evoke and possibly enhance auditory perception and has real potential to be implemented in an auditory prosthesis.