Optical stimulation of neurons

Current Funding

This project is funded in whole or in part with Federal funds from the National Institute of Deafness and Other Communication Disorders, National Institutes of Health, Department of Health and Human Services, under Contract No. HHSN260-2006-00006-C / NIH No. N01-DC-6-0006.

Additional funding

NIH-STTR: 1R41DC008515-01

NIH-SBIR: 2R44NS051926-02

E.R. Capita Foundation

Motivation and Aims for the research

Neural prosthetic devices are artificial extensions to the body that restore or supplement nervous system function that was lost during disease or injury.  Particular success has been realized in cochlear prostheses development.  The devices bypass damaged hair cells in the auditory system by direct electrical stimulation of the auditory nerve.  Stimulating discrete spiral ganglion cell populations in cochlear implant users' ears is similar to the encoding of small acoustic frequency bands in a normal-hearing person's ear.  In contemporary cochlear implants, however, the injected electric current is spread widely along the scala tympani and across turns.  Consequently, stimulation of spatially discrete spiral ganglion cell populations is difficult.  One goal of implant device development is to design cochlear implants that stimulate smaller populations of spiral ganglion cells.  In contrast to electrical stimulation, extreme spatially selective stimulation is possible using light.  Therefore, our long-term goal is to develop and build optical cochlear implant prostheses to stimulate small populations of spiral ganglion cells.  Steps towards this objective include (1) quantifying the optical parameters that allow for safe spiral ganglion cell stimulation over extended periods of time, (2) characterize the fundamental spatial and temporal properties of optical stimulation of the auditory nerve, (3) determining the spatial resolution for laser stimulation.  By accomplishing the first three goals within the first three years, (4) we will be able building and implanting the first animal cochlear implant electrode for long-term safety studies during year four and five.  Also, the results will provide a basic set of parameters that can be used for other neural interfaces that use optical radiation to stimulate neurons.