2002 Fiscal Year Final Research Report Summary
BASIC RESEARCH IN AUDITORY BRAINSTEM IIMPLANT
| Project/Area Number |
11307034
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KAGA Kimitaka DEPARTMENT OF OTORALYNGOLOGY, PROFESSOR, 医学部附属病院, 教授 (80082238)
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| Co-Investigator(Kenkyū-buntansha) |
MUROFUSHI Toshihisa DEPARTMENT OF OTORALYNGOLOGY, LECTURER, 医学部附属病院, 講師 (30242176)
YAMASOBA Tatsuya DEPARTMENT OF OTORALYNGOLOGY, ASSISTANT PROFESSOR, 医学部附属病院, 助教授 (60251302)
SUGASAWA Masashi DEPARTMENT OF OTORALYNGOLOGY, ASSISTANT PROFESSOR, 医学部附属病院, 助教授 (00179110)
ITO Ken DEPARTMENT OF OTORALYNGOLOGY, LECTURER, 医学部附属病院, 講師 (50251286)
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| Project Period (FY) |
1999 – 2002
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| Keywords | Surface microelectrode / Spike microelectrode / Spatio-temporal pattern / Evoked potential / Cerebral cortex / Neural recording |
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| Research Abstract |
Auditory brainstem implant (ABI) that electrically stimulates the cochlear nucleus has been clinically used for rehabilitation of deaf patients with bilateral acoustic neuroma. A current prosthetic device, however, cannot evoke even pitch sensation and thus brings few benefits. This research purpose to verify ABI capability by physiological experiments using rats. Our experimental system includes a spike microelectrode array for cochlear nucleus microstimulation and a surface microelectrode array for mapping evoked-potentials over the auditory cortex. We compared pure-tone-evoked cortical potential patterns with those evoked by cochlear nucleus microstimulation. Our 〓〓erimental results strongly suggest the microstimulation on the dorsal and ventral nuclei can access the cortical tonotopic organization, as acoustic stimuli do, possibly indicating the stimulation can evoke pitch sensation and thus substantially promising ABI capability.
Flring rate counting via conventional microelectrode
… More
s would uncover spatio-temporal neuronal patterns that are needed to better understand overall functions at a specific cortical area. Such patterns may be more easily accessible via cortical evoked potentials that arise from ensemble neuronal activities. We developed the novel multiple-site surface microelectrode that maps the cortical evoked potentials with as many sites and high spatial resolution as possible ; 69 recording sites, each size of which is 80-μm-square, over a 2-mm-square area. With common lithographic technologies, the conductive gold layer was sandwiched between an insulting polyimide layer a polyimide substrate. Unlike conventional stiff microelectrodes, the flexible polyimide substrate could follow the convex and pulsative cortical surface, to keep the recording sites stable there, and realize less-invasive epidural recording. The impedance od each site is around 200 k Ω At 1 kHz, proved small enough to detect reliable cortical signals. Through invivo experimentes on rat auditory cortexes, the electrode achieved significantly differntiated auditory evoked potential maps in response to varied acoustic stimuli.. These data proved feasibility of the electrode as a novel electrophysiological tool to obtain the spatio-temporal patterns in this ABI research. Less
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