title: Infrared neural stimulation fails to evoke neural activity in the deaf guinea pig cochlea.
abstract: At present there is some debate as to the processes by which infrared neural stimulation (INS) activates neurons in the cochlea, as the lasers used for INS can potentially generate a range of secondary stimuli e.g. an acoustic stimulus is produced when the light is absorbed by water. To clarify whether INS in the cochlea requires functioning hair cells and to explore the potential relevance to cochlear implants, experiments using INS were performed in the cochleae of both normal hearing and profoundly deaf guinea pigs. A response to laser stimulation was readily evoked in normal hearing cochlea. However, no response was evoked in any profoundly deaf cochleae, for either acute or chronic deafening, contrary to previous work where a response was observed after acute deafening with ototoxic drugs. A neural response to electrical stimulation was readily evoked in all cochleae after deafening. The absence of a response from optical stimuli in profoundly deaf cochleae suggests that the response from INS in the cochlea is hair cell mediated.
authors: Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia. Electronic address: thompson.alex.c@gmail.com.
authors: Alexander C
authors: AC
authors: Thompson
authors: Bionics Institute, East Melbourne, Australia; Medical Bionics Department, University of Melbourne, East Melbourne, Australia; Department of Otolaryngology, University of Melbourne, East Melbourne, Australia.
authors: James B
authors: JB
authors: Fallon
authors: Bionics Institute, East Melbourne, Australia; Medical Bionics Department, University of Melbourne, East Melbourne, Australia; Department of Otolaryngology, University of Melbourne, East Melbourne, Australia.
authors: Andrew K
authors: AK
authors: Wise
authors: Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia.
authors: Scott A
authors: SA
authors: Wade
authors: Bionics Institute, East Melbourne, Australia; Medical Bionics Department, University of Melbourne, East Melbourne, Australia; Department of Otolaryngology, University of Melbourne, East Melbourne, Australia.
authors: Robert K
authors: RK
authors: Shepherd
authors: Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia. Electronic address: pstoddart@swin.edu.au.
authors: Paul R
authors: PR
authors: Stoddart
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000818:Animals; D003051:Cochlea / Q000502:physiology / Q000503:physiopathology*; D019929:Cochlear Implantation; D003054:Cochlear Implants; D003638:Deafness / Q000503:physiopathology*; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000502:physiology*; D007259:Infrared Rays; D008297:Male; D009474:Neurons / Q000502:physiology; D013136:Spiral Ganglion / Q000502:physiology