| Project/Area Number |
16591735
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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 | KANAZAWA MEDICAL UNIVERSITY |
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Principal Investigator |
ONODA Norihiko Kanazawa Medical Univ., Sch.of Med, Prof., 医学部, 教授 (60106903)
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| Co-Investigator(Kenkyū-buntansha) |
TOMODA Kouichi Kanazawa Medical Univ., Sch.of Med., Prof., 医学部, 教授 (50164041)
SUGAI Tokio Kanazawa Medical Univ., Sch.of Med., Assoc.Prof., 医学部, 助教授 (90064625)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2004: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Guinea pig / Piriform cortex / Intrinsing signal / Odor concentration / Concentration- gradient / 内因性信号の起源 |
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| Research Abstract |
By optical imaging of intrinsic signals, we demonstrated a possible code for odor concentration in the anterior piriform cortex of the guinea-pig. Odor-induced cortical activation, which primarily originated in layer II, appeared in a narrow band beneath the rhinal sulcus over the lateral olfactory tract, corresponding to the dorsal part of the anterior piriform cortex. Lower concentrations activated the rostral region of the band, whereas higher ones generated caudally spreading activation, and the site at which neural activation reached its maximum extent depended upon odor concentration. Different odors with low concentrations generated distinct but somewhat overlapping patterns in the rostral region of the band, the limited extent of cortical activity may be one focal domain for each odor. It was hard to judge, however, that odor-specific domains appeared in the anterior piriform cortex, because the strong stimuli induced largely overlapping patterns. Furthermore, the total area activated increased in proportion to concentrations raised to a power of 0.5 to 0.9. Importantly, these imaging results were confirmed with unit recordings which indicated a rostro-caudal gradient in odor- sensitivity among cortical neurons. Our results suggest that the dorsal part of the anterior piriform cortex may be associated with odor concentration. Therefore, in addition to recruitment of more olfactory sensory cells and glomeruli in response to stronger stimuli, a rostro-caudal gradient in axonal projections from mitral/tufted cells and/or in association fibers may play an important role in odor-concentration coding in the anterior piriform cortex.
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