Introduction:
Conventional electrical cochlear implants allow for proper sound perception and speech understanding. Due to its poor frequency resolution however, reception of music and prosody as well as speech understanding in a noisy environment is limited. Optogenetic stimulation of the cochlea is a promising concept to activate spiral ganglion neurons more specifically and thus generate a higher frequency resolution. We aim for developing an animal model which allows us to evaluate frequency and intensity resolution after implantation of an optogenetic cochlear implant.
Material, Methods and Results:
The common marmoset (Callithrix jacchus) is a primate well investigated in behavioural studies. Their temporal bones share many similarities to human ones. In this animal model, we have developed a surgical access to the cochlea which allowed us to insert conventional electrical electrodes as well as LED-arrays for optical stimulation (optrode) via the round window. Furthermore, we used this access to inject viral vectors carrying the optogenetic construct into the cochlea.
After insertion of conventional implant electrodes, animals showed adequate responses in objective audiometric test as well as behavioural testing upon electrical stimulation of the cochlea.
Conclusion:
The common marmoset can be regarded as a suited animal model for evaluating conventional-electrical as well as optogenetic cochlear stimulation.
