AI Insight
This study evaluated f-Chrimson, a fast-closing channelrhodopsin variant, for optogenetic stimulation of the cochlea in Mongolian gerbils, measuring neural responses in the inferior colliculus (a midbrain auditory processing center). F-Chrimson supported energy-efficient activation of the auditory pathway at stimulation rates of 150 Hz or higher, outperforming slower channelrhodopsin variants CatCh and ChReef in temporal fidelity. Frequency selectivity and dynamic range were comparable to prior optogenetic approaches and exceeded those achieved with conventional electrical cochlear implants.
Why it matters
These findings suggest that optical cochlear implants using fast-gating channelrhodopsins could offer improved both spectral and temporal sound coding compared to current electrical cochlear implants, potentially enhancing speech understanding in noisy environments for hearing-impaired individuals.
⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
When hearing fails, stimulation of the auditory nerve by electrical cochlear implants (eCIs) partially restores hearing, with most eCI users achieving open speech understanding. However, the broad current spread from each electrode limits frequency coding and speech understanding in daily situations with background noise. Spatially confined optogenetic stimulation by future optical cochlear implants (oCIs) improves frequency coding but millisecond closing kinetics of channelrhodopsins (ChRs) might limit temporal coding. Here, we evaluated the utility of fast-closing f-Chrimson for processing temporal information in the auditory system of Mongolian gerbils. We recorded neural activity in the inferior colliculus evoked by f-Chrimson-mediated optogenetic stimulation of the cochlea. F-Chrimson enabled energy-efficient stimulation of the auditory pathway at rates [≥] 150 Hz, outperforming the slower ChR variants CatCh (blue) and ChReef (green). Energy thresholds for activation of the auditory pathway were in the low {micro}J range, between ChReef (sub-{micro}J) and CatCh. Dynamic range and frequency selectivity were comparable to previous observations with CatCh and outperformed electrical stimulation. In conclusion, employing fast-gating ChRs harnesses improved spectral coding without degrading temporal coding.
Source: Optogenetic cochlear stimulation evokes midbrain activity with near-physiological temporal fidelity