Real-Time Microendoscopic Calcium Imaging in a Freely Moving Mouse

Abstract

Source: Lee, H. et. al., Successful In vivo Calcium Imaging with a Head-Mount Miniaturized Microscope in the Amygdala of Freely Behaving Mouse. J. Vis. Exp. (2020)

This video demonstrates in vivo calcium imaging in a mouse using a gradient refractive index, or GRIN lens, and a miniaturized microscope. The setup combines head fixation within a frictionless mobile cage system, stimulating neurons and triggering calcium ion influx. The GRIN lens captures calcium signaling in the brain, enabling real-time visualization of neuronal activity.

Protocol

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.

NOTE: This protocol consists of six major steps: virus injection surgery, gradient refractive index (GRIN) lens implant surgery, validation of GRIN lens implantation, baseplate attachment, optical recording of GCaMP (fusion of green fluorescent protein (GFP), calmodulin (CaM), and M13, a peptide sequence from myosin light-chain kinase) signal during a behavior test, and data processing (Figure 1A). Except for surgery, the commercial software package (Inscopix) is used.

1. Stereotaxic surgery &....

Results

Figure 1: Schematic workflow and diagrams for stereotaxic surgery for in vivo microendoscopic calcium imaging in the L.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
26G needle	BD	302002	Surgery
AAV1-Syn-GCaMP7b-WPRE	Addgene	104493-AAV1	Surgery
AAV2/1-CaMKiiα-GFP	custom made		Surgery
Acrylic-dental cement (Ortho-jet Acrylic Pink)	Lang	1334-pink	Surgery & baseplate attachment
Air flow manipulator	Neurotar	NTR000253-04	Baseplate attachment
Amoxicillin	SIGMA	A8523-5G	Surgery
Carbon cage	Neurotar	180mm x 70mm	Baseplate attachment
Carprofen	SIGMA	PHR1452-1G	Surgery
Data processing software	INSCOPIX	INSCOPIX Data Processing Software	Baseplate attachment & behavior test
Dexamethasone	SIGMA	D1756-500MG	Surgery
Drill	Seyang	marathon-4	Surgery
Drill bur	ELA	US1/2, Shank104	Surgery
Glass needle	WPI	PG10165-4	Surgery
GRIN lens (INSCOPIX Proview Lens Probe)	INSCOPIX	1050-002208	Surgery
Hamilton Syringe	Hamilton	84875	Surgery
Head plate	Neurotar	Model 5	Surgery
Laptop computer	Samsung	NT950XBV	Surgery
Lens holder, Stereotaxic rod (INSCOPIX proview implant kit)	INSCOPIX	1050-004223	Surgery
Microscope gripper	INSCOPIX	1050-002199	Baseplate attachment
Microscope, DAQ software, hardware	INSCOPIX	nVista 3.0	Baseplate attachment & behavior test
Mobile homecage	Neurotar	MHC V5	Baseplate attachment
Moterized arm	Neurostar	Customized	Surgery
Moterized arm software	Neurostar	Customized	Surgery
Removable epoxy bond	WPI	Kwik-Cast	Surgery
Resin cement (Super-bond)	Sun medical	Super bond C&B	Surgery
Skull screw	Stoelting	51457	Surgery
Stereotaxic frame	Stoelting	51600	Surgery
Stereotaxic manipulator	Stoelting	51600	Baseplate attachment