1993 Fiscal Year Final Research Report Summary
Postnatal development and plasticity of sound localization centers
| Project/Area Number |
04670036
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
神経解剖学
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| Research Institution | Kanazawa University |
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Principal Investigator |
IKUDO Motoi Kanazawa Univ., med. Schl., Professor, 医学部, 教授 (80108141)
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| Co-Investigator(Kenkyū-buntansha) |
OKAYAMA Shigeo Kanazawa Univ., med. Schl., Assistant Professor, 医学部, 助手 (30019575)
KITAO Yasuko Kanazawa Univ., med. Schl., Assistant Professor, 医学部, 助手 (00019613)
AMANO Osamu Kanazawa Univ., med. Schl., Associate Professor, 医学部, 助教授 (70157874)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Neurogenesis / Inferior colliculus / Superior olive / Rat / BrdU / Auditory pathways / Plasticity / Postnatal development |
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| Research Abstract |
<Neurogenetical study>
By a combination of fluorescent retrograde axonal tracings and bromodeoxyuridine (BrdU) immunohistochemical techniques, time origins of projection neurons in the superior olive have been examined. In the lateral superior olive, neurons projecting to the contralateral inferior colliculus (IC) were generated on days E12 and E13, whereas neurons projcting to the ipsilateral IC were proliferated between days E14 and E16. In the medial superior olive (MSO), the IC projection neurons arose on E12, while, in the superior paraolivary nucleus, their peak production occurred on day E13. Also refer some publication (Kitao et al., brain Research, 1993) and oral presentations (International Workshopon Binaural Procssing in the Auditory Brainstem. Ottawa, Canada, 1993 ; Society for Neuroscience.Anaheim, California U.S.A., 1992).
<Normal development of auditory brainstem pathways and plasticity after unilateral ablation of the IC>
The results indicated that : 1) The projection froj the MSO to the IC was developed gradually in postnatal periodsas an exclusively uncrossed one without making axon-collaterals to the contralateral IC.2) When the IC was ablated unilaterally in certain postnatal period, many neurons died in the ipsilateral MSO as a result of axotomy. 3) An aberrant crossed projection to the contralateral IC occurs in some of the survived neurons in the MSO, although such aberrant fibers still maintained in adult were very few in number. 4) Growth of late-developing axons was a major factor in the plasticity of this system of projection.
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