Cortical neuroprostheses improve auditory coding and perception compared to cochlear implants

Abstract

Cochlear implants have transformed the treatment of hearing loss by enabling auditory perception through direct electrical stimulation of the auditory nerve. However, their effectiveness can be limited in noisy environments, for fine frequency resolution, and in patients lacking an intact auditory nerve. The auditory cortex offers a promising alternative target for neuroprosthetic stimulation, but it remains unclear whether direct cortical input can evoke percepts with the complexity and structure of natural sounds. Here we show that surface cortical implants in mice support robust and flexible auditory behaviour, surpassing cochlear implants in tasks requiring fine spectral, temporal, and noise-resistant discrimination. We also show that animals generalize seamlessly between cortical and acoustic stimuli without additional training, indicating that cortical stimulation can generate interpretable, sound-like percepts. Electrophysiological recordings revealed that cortical stimulation drives spatially and temporally structured neural activity in auditory cortex, resembling responses to natural sound. These findings establish that the auditory cortex can interpret spatially and temporally patterned electrical input in a behavioural relevant way. By linking neuroprosthetic stimulation to naturalistic neural representations and behavioural generalization, this work provides a mechanistic and functional foundation for cortical auditory neuroprostheses and points toward new strategies for restoring hearing through direct brain stimulation.