title: Radiant energy required for infrared neural stimulation.
abstract: Infrared neural stimulation (INS) has been proposed as an alternative method to electrical stimulation because of its spatial selective stimulation. Independent of the mechanism for INS, to translate the method into a device it is important to determine the energy for stimulation required at the target structure. Custom-designed, flat and angle polished fibers, were used to deliver the photons. By rotating the angle polished fibers, the orientation of the radiation beam in the cochlea could be changed. INS-evoked compound action potentials and single unit responses in the central nucleus of the inferior colliculus (ICC) were recorded. X-ray computed tomography was used to determine the orientation of the optical fiber. Maximum responses were observed when the radiation beam was directed towards the spiral ganglion neurons (SGNs), whereas little responses were seen when the beam was directed towards the basilar membrane. The radiant exposure required at the SGNs to evoke compound action potentials (CAPs) or ICC responses was on average 18.9 ± 12.2 or 10.3 ± 4.9 mJ/cm(2), respectively. For cochlear INS it has been debated whether the radiation directly stimulates the SGNs or evokes a photoacoustic effect. The results support the view that a direct interaction between neurons and radiation dominates the response to INS.
authors: Department of Otolaryngology, Northwestern University, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA.
authors: Xiaodong
authors: X
authors: Tan
authors: Department of Biomedical Engineering, University of Miami, Miami FL 33146, USA.|Department of Otolaryngology, University of Miami, Miami FL 33136, USA.
authors: Suhrud
authors: S
authors: Rajguru
authors: Department of Otolaryngology, Northwestern University, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA.
authors: Hunter
authors: H
authors: Young
authors: Department of Otolaryngology, Northwestern University, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA.|Key Laboratory of Biorheological Science and Technology, Bioengineering College, Chongqing University, Chongqing 400044, China.
authors: Nan
authors: N
authors: Xia
authors: Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
authors: Stuart R
authors: SR
authors: Stock
authors: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Ave. Argonne, IL 60439 USA.
authors: Xianghui
authors: X
authors: Xiao
authors: Department of Otolaryngology, Northwestern University, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA.|Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL 60208, USA.|The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL 60208, USA.
authors: Claus-Peter
authors: CP
authors: Richter
mesh_terms: D000818:Animals; D003054:Cochlear Implants; D046690:Deep Brain Stimulation / Q000295:instrumentation* / Q000379:methods; D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology / Q000528:radiation effects; D005260:Female; D005336:Fiber Optic Technology / Q000295:instrumentation; D006168:Guinea Pigs; D007245:Inferior Colliculi / Q000502:physiology* / Q000528:radiation effects; D007259:Infrared Rays / Q000627:therapeutic use*; D008029:Lighting / Q000295:instrumentation*; D008297:Male; D009474:Neurons / Q000502:physiology* / Q000528:radiation effects; D010775:Photic Stimulation; D011829:Radiation Dosage