Optical parameter variability in laser nerve stimulation: a study of pulse duration, repetition rate, and wavelength.
Pulsed lasers can evoke neural activity from motor as well as sensory neurons in vivo. Lasers allow more selective spatial resolution of stimulation than the conventional electrical stimulation. To date, few studies have examined pulsed, mid-infrared laser stimulation of nerves and very little of the available optical parameter space has been studied. In this study, a pulsed diode laser, with wavelength between 1.844-1.873 microm, was used to elicit compound action potentials (CAPs) from the auditory system of the gerbil. We found that pulse durations as short as 35 micros elicit a CAP from the cochlea. In addition, repetition rates up to 13 Hz can continually stimulate cochlear spiral ganglion cells for extended periods of time. Varying the wavelength and, therefore, the optical penetration depth, allowed different populations of neurons to be stimulated. The technology of optical stimulation could significantly improve cochlear implants, which are hampered by a lack of spatial selectivity.
Izzo
Agnella D
AD
Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA. a-izzo@northwestern.edu
Walsh
Joseph T
JT
Jansen
E Duco
ED
Bendett
Mark
M
Webb
Jim
J
Ralph
Heather
H
Richter
Claus-Peter
CP
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005849:Gerbillinae; D053685:Laser Therapy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity