Combined optogenetic and electrical stimulation of auditory neurons increases effective stimulation frequency—an in vitro study

摘要

Objective. The performance of neuroprostheses, including cochlear and retinal implants, is currentlyconstrained by the spatial resolution of electrical stimulation. Optogenetics has improved thespatial control of neurons in vivo but lacks the fast-temporal dynamics required for auditory andretinal signalling. The objective of this study is to demonstrate that combining optical and electricalstimulation in vitro could address some of the limitations associated with each of the stimulusmodes when used independently. Approach. The response of murine auditory neurons expressingChR2-H134 to combined optical and electrical stimulation was characterised using whole cellpatch clamp electrophysiology. Main results. Optogenetic costimulation produces a three-foldincrease in peak firing rate compared to optical stimulation alone and allows spikes to be evokedby combined subthreshold optical and electrical inputs. Subthreshold optical depolarisation alsofacilitated spiking in auditory neurons for periods of up to 30 ms without evidence of wide-scaleNa~+ inactivation. Significance. These findings may contribute to the development of spatially andtemporally selective optogenetic-based neuroprosthetics and complement recent developments in‘fast opsins’.