Large-scale two-photon calcium imaging in freely moving mice.
Cell 2022;
185:1240-1256.e30. [PMID:
35305313 PMCID:
PMC8970296 DOI:
10.1016/j.cell.2022.02.017]
[Citation(s) in RCA: 88] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 01/12/2022] [Accepted: 02/14/2022] [Indexed: 11/29/2022]
Abstract
We developed a miniaturized two-photon microscope (MINI2P) for fast, high-resolution, multiplane calcium imaging of over 1,000 neurons at a time in freely moving mice. With a microscope weight below 3 g and a highly flexible connection cable, MINI2P allowed stable imaging with no impediment of behavior in a variety of assays compared to untethered, unimplanted animals. The improved cell yield was achieved through a optical system design featuring an enlarged field of view (FOV) and a microtunable lens with increased z-scanning range and speed that allows fast and stable imaging of multiple interleaved planes, as well as 3D functional imaging. Successive imaging across multiple, adjacent FOVs enabled recordings from more than 10,000 neurons in the same animal. Large-scale proof-of-principle data were obtained from cell populations in visual cortex, medial entorhinal cortex, and hippocampus, revealing spatial tuning of cells in all areas.
We made a light-weight 2-photon miniscope for calcium imaging in freely moving mice
Stable high-quality imaging was observed during a wide spectrum of behaviors
Activity can be monitored in volumes of over 1,000 visual or entorhinal-cortex cells
A custom-designed z-scanning module allows fast imaging across multiple planes
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