Dissecting divergent local circuit function during memory formation in hippocampus

2021 Fiscal Year Research-status Report

• Project/Area Number: 21K15214
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Sekulic Vladislav 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, 基礎科学特別研究員 (60865492)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: calcium imaging / hippocampus / memory encoding

Outline of Annual Research Achievements

In FY2021, I successfully implanted GRIN lenses and performed 1-photon calcium imaging recordings from 15 mice constituting the entire dataset for a major experiment.

I acquired more 1-photon miniature endoscope hardware and a filter set for imaging from cells with red fluorescence to continue the experiment combining in vivo activity recording and immediate early gene (IEG) memory labelling in the same mice. These recordings will be performed in FY2022.

Current Status of Research Progress

1: Research has progressed more than it was originally planned.

Reason

I had initially anticipated that the main recordings for the calcium imaging dataset would take the entire FY year or even 2 years, but I was able to complete them within 6 months. This will allow further recordings and expanded research results. The benefit of the Miniscope 1-photon system that I acquired using KAKENHI funds is tremendous as it is a reliable and flexible system that performed much more smoothly than anticipated. Furthermore, as I had gotten comfortable and highly capable with the GRIN lens surgeries, all of my mice had successful implants and could be recorded from (success rate nearly 100%), allowing for rapid acquisition of a large dataset.

Strategy for Future Research Activity

The further steps to be taken in FY2022 is to image from a new set of mice using simultaneous red imaging of memory-dependent molecular markers that label novel engram forming cells, while also imaging dynamic in vivo activity using the previous 1-photon Miniscope. This will require the use of two scopes, one of which I will assemble from parts I already acquired using my KAKENHI funds.

Causes of Carryover

I plan on acquiring more GRIN lenses and 1-photon Miniscope hardware for performing additional experiments. Additionally, I will purchase a new Cre genotype mouse line for these more refined experiments.