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Proceedings Paper

Laser stimulation of the auditory system at 1.94 µm and microsecond pulse durations
Author(s): Agnella D. Izzo; Joseph T. Walsh Jr.; Heather Ralph; Jim Webb; Jonathon Wells; Mark Bendett; Claus-Peter Richter
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Paper Abstract

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 5μs, 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.

Paper Details

Date Published: 11 March 2008
PDF: 7 pages
Proc. SPIE 6854, Optical Interactions with Tissue and Cells XIX, 68540C (11 March 2008); doi: 10.1117/12.761315
Show Author Affiliations
Agnella D. Izzo, Northwestern Univ. (United States)
Joseph T. Walsh Jr., Northwestern Univ. (United States)
Heather Ralph, Northstar Neuroscience (United States)
Jim Webb, Aculight Corp. (United States)
Jonathon Wells, Aculight Corp. (United States)
Mark Bendett, Aculight Corp. (United States)
Claus-Peter Richter, Northwestern Univ. (United States)

Published in SPIE Proceedings Vol. 6854:
Optical Interactions with Tissue and Cells XIX
Steven L. Jacques; William P. Roach; Robert J. Thomas, Editor(s)

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