Spatial extent of cochlear infrared neural stimulation determined by tone-on-light masking

AI Matic, JT Walsh Jr, CP Richter - Journal of biomedical …, 2011 - spiedigitallibrary.org
AI Matic, JT Walsh Jr, CP Richter
Journal of biomedical optics, 2011spiedigitallibrary.org
Artificial neural stimulation is widely used in clinic, rehabilitation, and research. One of the
limitations of electrical stimulation is the current spread in tissue. Recently, pulsed mid-
infrared laser stimulation of nerves has been investigated as an alternative stimulation
method. The likely benefits of infrared neural stimulation (INS) include spatial selectivity of
stimulation, noncontact mode of operation, and the lack of stimulation artifact in
simultaneous electrical recordings. The hypothesis for this study is that INS of the cochlear …
Artificial neural stimulation is widely used in clinic, rehabilitation, and research. One of the limitations of electrical stimulation is the current spread in tissue. Recently, pulsed mid-infrared laser stimulation of nerves has been investigated as an alternative stimulation method. The likely benefits of infrared neural stimulation (INS) include spatial selectivity of stimulation, noncontact mode of operation, and the lack of stimulation artifact in simultaneous electrical recordings. The hypothesis for this study is that INS of the cochlear spiral ganglion at low pulse energy is as spatially selective as low-level tonal stimulation of the cochlea. Spatial selectivity was measured using a masking method. An optical pulse with fixed optical parameters was delivered through a 200-μm diameter optical fiber. An acoustic tone, variable in frequency and level, was presented simultaneously with the optical pulse. Tone-on-light masking in gerbils revealed tuning curves with best frequencies between 5.3 and 11.4 kHz. The width of the tone-on-light tuning curves was similar to the width of tone-on-tone tuning curves. The results indicate that the spatial area of INS in the gerbil cochlea is similar to the cochlear area excited by a low level acoustic tone, showing promising results for future use of INS in implantable cochlear prostheses.
SPIE Digital Library