| Project/Area Number |
08458267
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
神経・脳内生理学
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
SHINODA Yoshikazu Tokyo Medical and Dental University, Department of Physiology, Professor, 医学部, 教授 (60010104)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1996: ¥5,700,000 (Direct Cost: ¥5,700,000)
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| Keywords | saccade / ocular motoneuron / biocytin / PPRF / HRP / superior colliculus / eye movement / neurophysiology |
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| Research Abstract |
To understand the neural mechanisms of saccadic eye movement generation, the neural organization from the superior colliculuc (SC) to ocular motoneurons in the horizontal oculomotor system was analyzed in the anesthetized cat. Intracellular responses to stimulation ot the SC were analyzed in abducens motoneurons, medial rectus motoneurons and internuclear neurons (INNs) in the abducens nucleus. Abducens motoneurons received disynaptic excitatory inputs from the contralataeral SC via the ipsilateral paramedian pontine reticular formation (PPRF) and disynaptic inhibitory inputs from the ipsilateral SC via the contralateral PPRF.These electrophysiological findings were confirmed by anatomical experiments. Last-order premotor neurons were labeled transneuronally after injecting WGA-HRP into the abducens nerve, and in the same preparations dextran-biotin injection into the SC labeled axon terminals of tectoreticular neurons orthgradely in the contralateral PPRF rostral and caudal to the abducens nucleus. These axon terminals of tectoreticular fibers made direct contacts with last-order premotor neurons terminating on ipsilateral abducens motoneurons and contralateral abducens motoneurons. INNs in the abducens nucleus received disynaptic excitatory inputs from the contralateral SC and disynaptic inhibitory inputs from the ipsilateral SC.This pattern was the same as in abducens motoneurons. Medial rectus motoneurons received trisynaptic excitatory inputs from the ipsilateral SC via the contralateral INNs. Two groups of tectoreticular neurons were identified to convey output from the SC to the PPRF.One group projected to the PPRF,but not to the spinal cord, and the other group projected to both the PPRF and the spinal cord.
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