Optical stimulation of the hearing and deaf cochlea under thermal and stress confinement condition

M. Schultz, P. Baumhoff, N. Kallweit, M. Sato, A. Krüger, T. Ripken, T. Lenarz, A. Kral

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

3 Citations (Scopus)

Abstract

There is a controversy, to which extend cochlear stimulation with near infrared laser pulses at a wavelength of 1860 nm is based on optoacoustic stimulation of intact hair cells or-in contrast-is based on direct stimulation of the nerve cells in absence of functional hair cells. Thermal and stress confinement conditions apply, because of the pulse duration range (5 ns, 10 μs-20 ms) of the two lasers used. The dependency of the signal characteristics on pulse peak power and pulse duration was investigated in this study. The compound action potential (CAP) was measured during stimulation of the cochlea of four anaesthetized guinea pigs, which were hearing at first and afterwards acutely deafened using intracochlear neomycin-rinsing. For comparison hydrophone measurements in a water tank were performed to investigate the optoacoustic signals at different laser interaction regimes. With rising pulse peak power CAPs of the hearing animals showed first a threshold, then a positively correlated and finally a saturating dependency. CAPs also showed distinct responses at laser onset and offset separated with the pulse duration. At pulse durations shorter than physiological response times the signals merged. Basically the same signal characteristics were observed in the optoacoustic hydrophone measurements, scaled with the sensitivity and response time of the hydrophone. Taking together the qualitative correspondence in the signal response and the absence of any CAPs in deafened animals our results speak in favor of an optoacoustic stimulation of intact hair cells rather than a direct stimulation of nerve cells.

Original languageEnglish
Title of host publicationOptical Techniques in Neurosurgery, Neurophotonics, and Optogenetics
EditorsHenry Hirschberg, Steen J. Madsen, E. Duco Jansen, Qingming Luo, Samarendra K. Mohanty, Nitish V. Thakor
Place of PublicationWashington
PublisherSPIE
Pages1-7
Number of pages7
Volume8928
ISBN (Electronic)9780819498410
DOIs
Publication statusPublished - 1 Jan 2014
Externally publishedYes
EventOptical Techniques in Neurosurgery, Neurophotonics, and Optogenetics - San Francisco, CA, United States
Duration: 1 Feb 20144 Feb 2014

Publication series

NameProgress in Biomedical Optics and Imaging
PublisherSPIE
Number3
Volume15
ISSN (Electronic)1605-7422

Conference

ConferenceOptical Techniques in Neurosurgery, Neurophotonics, and Optogenetics
CountryUnited States
CitySan Francisco, CA
Period1/02/144/02/14

Keywords

  • absorption
  • cochlea
  • laser
  • optoacoustics
  • otolaryngology
  • physiology
  • water

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