2022 Fiscal Year Research-status Report
Elucidating the circuits of functional lateralization in the hippocampus
| Project/Area Number |
22K15234
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
Guan Hefei 国立研究開発法人理化学研究所, 脳神経科学研究センター, 特別研究員 (00930273)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Keywords | Spatial memory / Hippocampus |
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| Outline of Annual Research Achievements |
The first stage of the project involved characterizing the inhibitory effects and time course of viral expression of Gi-DREADD and KOR-DREADD in the hippocampus, as well as examining their corresponding ligand effects on in vivo hippocampal activity.
For the second stage, behavioral tasks were conducted to investigate the different functions of the left and right CA3 regions in spatial navigation and memory. In the object location test, mice were trained with two familiar objects, and during the second session of recall, one of the objects was moved to a different location after the left CA3 was silenced instead of the right CA3. The mice spent more time exploring the object in the novel location, which is attributed to their innate preference for novelty. These findings suggest that the left CA3 region is more crucial for the acquisition of spatial memory.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The research project is progressing relatively smoothly. The planned assessment of DREADD-mediated silencing of neural activity in the bilateral hippocampus has been completed as scheduled, as have the behavioral tasks designed to test the spatial navigation and memory functions of the left and right CA3 regions. However, there has been a delay in starting the in vivo recording experiment due to the late delivery of a camera necessary for detecting animal behavior in the object location test. We are expecting to receive the new camera soon, and to ensure that we stay on track with the planned schedule, a part-time student has been hired to assist with the preparation of the recording experiment.
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| Strategy for Future Research Activity |
As outlined in the grant proposal, the first step of the study will be to investigate whether the output of the left and right CA3 regions plays differential roles in the coordination of bilateral CA1 spatial coding. This will be achieved by injecting different viruses in the left and right CA3 regions and recording simultaneously in the bilateral CA1 regions while mice navigate a linear track.
Additionally, the study will involve recording from bilateral CA1 regions while mice perform object location tasks, in order to further understand the mechanisms underlying the differences between the left and right CA3 regions in spatial memory. I will adhere to the plan outlined in the grant proposal throughout the study.
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| Causes of Carryover |
The incurred amount can be attributed to two main factors. Firstly, I was unable to attend the international conference due to the ongoing COVID-19 situation. Additionally, I faced difficulties in finding a suitable part-timer to assist with my research, as originally planned.
However, in the upcoming fiscal year, I have made arrangements to attend the international conference, and I have already found a part-time assistant who will support me in conducting my experiments.
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