| Project/Area Number |
17591807
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | St. Marianna University School of Medicine |
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Principal Investigator |
OCHI Kentaro St. Marianna University School of Medicine, Department of Otolaryngology, Assistant Professor, 医学部, 非常勤講師 (20214158)
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| Co-Investigator(Kenkyū-buntansha) |
OYAKE Daisuke St. Marianna University School of Medicine, Department of Otolaryngology, Assistant, 医学部, 助手 (00367343)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | guinea pig / auditory cortex / single unit / tinnitus / salicylate acid / quinine / シグナルユニット / 可塑性 |
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| Research Abstract |
This study examined the mechanisms underlying tinnitus by making single-unit recordings in the guinea pig auditory cortex. The firing rate increased and the activity of individual single units became more synchronized in the presence of a sound stimulus, and such changes may also occur in the auditory cortex of a patient experiencing tinnitus. We observed increased synchronization but no change in firing rate after the administration of tinnitus-inducing drugs (salicylate or quinine) in cat auditory cortex. The behavioral results suggested that the tinnitus induced by administering salicylate or quinine affected the region of the primary auditory cortex with a characteristic frequency 9-10 kHz, and we examined the activity of the auditory cortex in this region. Because our peripheral auditory experiments were performed on guinea pigs, we also performed cortical experiments in guinea pigs in order to allow direct comparison between the peripheral and cortical data, which contrasts with the available cortical data mainly being from cat. With support from Professor Wallace, we recently recorded the guinea pig cortical activity in up to 128 single units using Brain Ware.
Firstly, we determined the normal spontaneous and stimulated activities in the guinea pig auditory cortex, which, as suggested by Professor Wallace, differed somehow from those in cat. Secondly, we evaluated the effects of tinnitus-inducing drugs (salicylate and quinine) on the auditory cortex. Intramuscular administration of quinine induced no marked change in spontaneous activity in the 9-to 10-kHz region of the primary auditory cortex. However, synchronization was increased after the administration of quinine. These results suggest that increased synchronization activity is related to the mechanisms underlying tinnitus.
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