| Project/Area Number |
16300114
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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 |
Nerve anatomy/Neuropathology
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| Research Institution | National Institute for Physiological Sciences |
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Principal Investigator |
SHIGEMOTO Ryuichi National Institute for Physiological Sciences, Cerebral Research, Professor, 大脳皮質機能研究系, 教授 (20221294)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAO Souichi RIKEN, Brain Science Institute, Laboratory Head, 脳科学研究総合センター, チームリーダー (40164397)
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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 |
¥15,200,000 (Direct Cost: ¥15,200,000)
Fiscal Year 2005: ¥4,300,000 (Direct Cost: ¥4,300,000)
Fiscal Year 2004: ¥10,900,000 (Direct Cost: ¥10,900,000)
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| Keywords | Glutamate receptors / Long-term depression / cerebellum / motor learning / Horizontal optokinetic response / AMPA receptors / Purkinie cells / Synapses |
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| Research Abstract |
Short- and long-term memory is believed to be encoded by modifications in synaptic strength. Morphological substrates for the modification, however, have not been well demonstrated in vivo. We used a simple, cerebellar motor learning task, short- and long-term adaptation of horizontal optokinetic response (HOKR), to study the link between learning and underlying changes in synapses and synaptic AMPA receptors. Long-term depression of parallel fiber (PF)-Purkinje cell (PC) synapses in the flocculus is involved in this type of cerebellar motor learining. To investigate learning-dependent changes of synaptic AMPA glutamate receptors, we used SDS-digested freeze-fracture replica labeling, which can detect AMPA channels with one-to-one detection sensitivity. PF-PC synapses were identified with clusters of intramembrane particles on E-face and immunogold labeling for delta2 receptors. Almost all PF-PC synapses were labeled with immunogold particles for AMPA receptors. In short-term adaptation of HOKR induced with one hour training, we found a significant reduction of labeling for AMPA receptors at PF-PC synapses in the middle one third of the flocculus but no changes in synapse density. No such difference in AMPAR density was detected in the flocculus of untrained animals or in the paraflocculus of the trained animals. On the contrary, in long-term adaptation induced with the one hour training for five days, we detected no significant difference in AMPA receptor density but found significant reduction of synapse density in the flocculus of trained animals. These results suggest that memory traces for short-and long-term memory are differently formed in the cerebellar motor learning.
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