| Project/Area Number |
12671677
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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 | Nara Medical University |
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Principal Investigator |
WADA Yoshiro Nara Medical University, School of Medicine, Assistant Professor, 医学部, 講師 (80240810)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2000: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Keywords | naso-occipital / linear motion / otolith organ / vestibular / vergence / visual / monkey / 前後方向 / 直線運動 / 眼球運動 / 固視 |
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| Research Abstract |
Vergence eye movements are elicited by visual stimuli and also naso-occipital (NO) linear head motion. As the first step in understanding the neural mechanisms of vergence eye movements during NO linear motion, I studied the effects of visual stimulus on the oculomotor response to forward linear motion in monkeys.
For this purpose, I constructed the new experiment system using a linear sled, a visual stimulator and an eye recording system. I used alert Japanese monkeys (Macaca fuscata) previously trained to fixate small targets. During recording sessions, the monkey was seated in a chair with its head secured by a head holder. I measured the horizontal and vertical eye positions binocularly using an electromagnetic search-coil system at 1 kHz. The monkey chair was mounted on a linear sled riding, which generated constant linear accelerations of 0.1 - 0.5 g along the NO-axis. A random-dot pattern (= RD, 69^ox69^o) large-field visual scene and/or a red center fixation target (= FT, 0.3^o) were/was back-projected onto a screen 35 cm away from the monkey. The results reveal that the four kinds vergence responses were elicited by forward linear motion as follows ;
a. Divergence responses to vestibular stimulus with latencies of 4 - 6 ms
b. Convergence responses to vestibular stimulus with latencies of around 10 ms
c. Convergence responses to RD large-field visual scene with latencies of around 45 ms
d. Convergence responses to FT with latencies of around 70 ms
RD (= c) and FT (= d) increased convergence responses to vestibular stimulus (= b). The effects of RD (= c) were stronger than those of FT (= d). These data may show that the neural mechanisms of convergence responses to RD (= c) were not the same as those of convergence responses to FT (= d).
Divergence responses with ultra short latencies (= a) were the eye responses we didn't expect. They should be the unknown vergence eye responses and next I will clarify their neural mechanisms and functions.
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