| Project/Area Number |
26750378
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Basic / Social brain science
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
Middleton Steven 国立研究開発法人理化学研究所, 脳科学総合研究センター, 研究員 (60526797)
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| Project Period (FY) |
2014-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2015: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2014: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
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| Keywords | CA3 / Hippocampus / Ripples / Memory / Spatial coding / hippocampus / sleep / ripples / electrical coupling / gap junctions |
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| Outline of Final Research Achievements |
The project aim was to elucidate the role of ripples in memory. Since sharp wave ripples are generated in hippocampal area CA3, we used the transgenic CA3-tetanus toxin mouse line which allows blockade of CA3 output.
We recorded from both mutant and control mice performing a spatial navigation task. We found that when hippocampal area CA3 was blocked ripple frequency was lower than in control mice. However, place cells could still reliably encode the animals current position in space. Phase precession which is the progressive shift of spikes within a place field to earlier theta phases still occurred. However, surprisingly when we looked across the population of CA1 neurons, theta sequences, which are short bursts of place cell activity (lasting approximately 125ms) encoding the animals current position and previous and forward trajectories, were not detectable. This demonstrated that CA3 is key to the temporal ordering of spatial memory segments in the CA1 ensemble.
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