Laser stimulation of the auditory system at 1.94μm and microsecond pulse durations

Agnella D. Izzo, Jay Walsh, Heather Ralph, Jim Webb, Jonathon Wells, Mark Bendett, Claus-Peter Richter

Research output: Chapter in Book/Report/Conference proceedingConference contribution

9 Scopus citations


Light can artificially stimulate nerve activity in vivo. A significant advantage of optical neural stimulation is the potential for higher spatial selectivity when compared with electrical stimulation. An increased spatial selectivity of stimulation could improve significantly the function of neuroprosthetics, such as cochlear implants. Cochlear implants restore a sense of hearing and communication to deaf individuals by directly electrically stimulating the remaining neural cells in the cochlea. However, performance is limited by overlapping electric fields from neighboring electrodes. Here, we report on experiments with a new laser, offering a previously unavailable wavelength, 1.94μm, and pulse durations down to 5 μs, to stimulate cochlear neurons. Compound action potentials (CAP) were evoked from the gerbil cochlea with pulse durations as short as 1μs. Data show that water absorption of light is a significant factor in optical stimulation, as evidenced by the required distance between the optical fiber and the neurons during stimulation. CAP threshold measurements indicate that there is an optimal range of pulse durations over which to deposit the laser energy, less than ∼100μs. The implications of these data could direct further research and design of an optical cochlear implant.

Original languageEnglish (US)
Title of host publicationOptical Interactions with Tissue and Cells XIX
StatePublished - Apr 21 2008
EventOptical Interactions with Tissue and Cells XIX - San Jose, CA, United States
Duration: Jan 21 2008Jan 23 2008


OtherOptical Interactions with Tissue and Cells XIX
Country/TerritoryUnited States
CitySan Jose, CA


  • Cochlear implant
  • Current spread
  • Optical stimulation
  • Selectivity
  • Spiral ganglion cell

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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