2001 Fiscal Year Final Research Report Summary
Effect on horizontal and vertical optokinetic nystagmus of lateral terminal nucleus of the accesory optic system and midline lesions in the pretectum of monkeys
| Project/Area Number |
11671710
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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 |
WATANABE Shoji St. Marianna University School of Medicine, M.D., 医学部, 助手 (00257396)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Tadashi Yamagata University, School of Medicine, associated doctor, 医学部, 助教授 (10125776)
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| Project Period (FY) |
1999 – 2001
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| Keywords | optokinetic nystagmus / nucleus of the optic tract / monkey / lateral nucleus of accessory optic system |
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| Research Abstract |
The nucleus of the optic tract (NOT), an important visuo-motor relay between the retina and preoculomotor structures, is responsible for mediating horizontal optokinetic nystagmus (OKN) in monkeys, cats, rabbits and rats. In addition to its projection to the vestibular nuclei, the NOT has a prominent projection to the contralateral NOT via the posterior commissure. In order to evaluate the role of the commissural fibers between the NOTs in OKN, we cut the posterior commissure in three Macaca fuscata. [Results] (1) The gain reduction in the rapid rise and steady state slow-phase velocity of OKN can be explained by removal of an excitatory signal mediated by commissural fibers to the inhibitory interneurons in the contralateral NOT. However, interrupting the commissural fibers has noihing to do with the velocity storage mechanism, because time-constants of OKAN mostly remained unchanged by the lesion. (2) The lesions of the lateral nucleus of accessory optic system (LTN) abolished the nystagmus with slow-phase toward-up. The horizontal OKN toward lesioned side were developed well. The LTN may be responsible for not the vertical OKN but also horizontal OKN.
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