title: Multichannel cochlear implant for selective neuronal activation and chronic use in the free-moving Mongolian gerbil.
abstract: Animal models for chronic multichannel cochlear implant stimulation and selective neuronal activation contribute to a better understanding of auditory signal processing and central neural plasticity.
  
  
  
  This paper describes the design and surgical implantation of a multichannel cochlear implant (CI) system for chronic use in the free-moving gerbil. For chronic stimulation, adult-deafened gerbils were connected to a multichannel commutator that allowed low resistance cable rotation and stable electric connectivity to the current source.
  
  
  
  Despite the small scale of the gerbil cochlea and auditory brain regions, final electrophysiological mapping experiments revealed selective and tonotopically organized neuronal activation in the auditory cortex. Contact impedances and electrically evoked auditory brainstem responses were stable over several weeks demonstrating the long-term integrity of the implant and the efficacy of the stimulation.
  
  
  
  Most animal models on multichannel signal processing and stimulation-induced plasticity are limited to larger animals such as ferrets, cats and primates. Multichannel CI stimulation in the free-moving rodent and evidence for selective neuronal activation in gerbil auditory cortex have not been previously reported.
  
  
  
  Overall, our results show that the gerbil is a robust rodent model for selective and tonotopically organized multichannel CI stimulation. We anticipate that this model provides a useful tool to develop and test both passive stimulation and behavioral training strategies for plastic reorganization and restoration of degraded unilateral and bilateral central auditory signal processing in the hearing impaired and deaf central auditory system.
authors: Comprehensive Hearing Center, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany. Electronic address: wiegner_a1@ukw.de.
authors: Armin
authors: A
authors: Wiegner
authors: Department of Otolaryngology-Head and Neck Surgery, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States. Electronic address: cgwrigh@utdallas.edu.
authors: Charles G
authors: CG
authors: Wright
authors: Comprehensive Hearing Center, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany. Electronic address: vollmer_m@ukw.de.
authors: Maike
authors: M
authors: Vollmer
mesh_terms: D000161:Acoustic Stimulation; D000704:Analysis of Variance; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity; D001306:Auditory Pathways; D001931:Brain Mapping; D019929:Cochlear Implantation / Q000295:instrumentation / Q000379:methods; D003054:Cochlear Implants; D003638:Deafness / Q000139:chemically induced / Q000601:surgery*; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005849:Gerbillinae; D009355:Neomycin / Q000633:toxicity; D009474:Neurons / Q000502:physiology*; D014851:Wakefulness
chemical_list: D000900:Anti-Bacterial Agents; D009355:Neomycin
keywords: Auditory cortex; Channel selectivity; Chronic electric stimulation; Deafness; Evoked auditory brainstem responses; Impedance; Mongolian gerbil; Multichannel cochlear implant; Tonotopy