Cochlear Implant Surgery and Electrically-evoked Auditory Brainstem Response Recordings in C57BL/6 Mice
Charlotte Amalie navntoft1, 2, Jeremy Marozeau1, Tania R Barkat2
1Hearing Systems Group, Department of Electrical Engineering, Technical University of Denmark
2Brain and Sound Lab, Department of Biomedicine, Basel University, 4056 Basel, Switzerland
Cochlear implants (CIs) are neuroprosthetic devices that can provide a sense of hearing to deaf people. However, a CI cannot restore all aspects of hearing. Improvement of the implant technology is needed if CI users are to perceive music and perform in more natural environments, such as hearing out a voice with competing talkers, reflections, and other sounds. Such improvement includes the necessity of experimental animals to better understand the mechanisms of electric stimulation in the cochlea and in its response in the whole auditory system. The mouse is an increasingly attractive model due to the many genetic models available. However, the limited use of this species as a CI model is mainly due to the difficulty of implanting small electrode arrays. More details of the surgical procedure are therefore of great interest to expand the use of mice in CI research.
Here, we describe in detail the protocol for acute deafening and cochlear implantation of an electrode array in the C57BL/6 mouse strain. We demonstrate the functional efficacy of this procedure with electrically-evoked auditory brainstem response (eABR) and show examples of facial nerve stimulation. Finally, we also discuss the importance of including a deafening procedure when using a normal hearing animal. This mouse model provides a powerful opportunity to study genetic and neurobiological mechanisms that would be of relevance for CI users.