Auditory Neuroscience and Optogenetics Laboratory

The Auditory Neuroscience and Optogenetics Laboratory studies how the auditory system processes acoustic information in normal and prosthetic hearing. We study the requirement in frequency resolution of auditory coding in the cochlea for vocal communication in primates working with marmosets as a non-human primate model with a rich vocal communication. Our work is driven by the motivation to enhance the frequency resolution of sound coding by the clinical cochlear implant for improved hearing restoration.

The cochlear implant, used worldwide by more than 500.000 hearing impaired people, typically enables open speech understanding and is considered the most successful neuroprosthesis. Nonetheless, listening in noisy environments as well as music appreciation remain challenging mostly because of the poor frequency and intensity resolution that results from broad current spread from of each of the 1-2 dozens of electrode contacts (see image above: Electrical Cochlear Implant). Since light can be conveniently focused, using optogenetic stimulation of the spiral ganglion of the cochlea (see image above: Optical Cochlear Implant) promises a fundamental improvement of frequency and intensity coding compared to that achievable with electrical cochlear implants.

This principle involves the expression of light-sensitive ion channels, so called channelrhodopsins in the neurons in order to render them light-sensitive. Placing linear emitter arrays (e.g. (Gossler et al., 2014), see figure 1) into the cochlea, one might be enable true multichannel stimulation with tens of independent information channels to the neurons. Building on our work in rodents at the University Medical Center Göttingen (Hernandez et al., 2014, see figure 2), our research at the German Primate Center employs the marmoset as a late preclinical primate model to study the feasibility of optogenetic cochlear implants prior to translation into the clinic and specifically to gain insights from behavioral experiments into the quality of sound perception with optogenetic stimulation of the cochlea in comparison to acoustic and electrical stimulation.

Funding comes from the European Research Council through the advanced grant OptoHear, the DFG Leibniz Program, the University Medical Center Göttingen and State of Lower Saxony.