Installation of Optical Windows in the Brain of Transgenic Mice to Image Neural Activities

Abstract

Source: Lin, X., et al. Imaging Neural Activity in the Primary Somatosensory Cortex Using Thy1-GCaMP6s Transgenic Mice. J. Vis. Exp. (2019).

This video demonstrates the brain's neural activity recording through an optical window in transgenic mice. The mice express a fluorescent protein that enables the detection of neural activities. A small portion of the skull is carefully removed to install an optical window, and the skull is then covered with black cement to block light before imaging.

Protocol

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

1. Preparing the Animal for Imaging

1. Place sterile gauze, cotton swabs, and autoclaved surgical tools in the surgery area. Turn on a Micro Bead Sterilizer for intersurgery sterilization of surgical tools.
2. Anesthetize the mouse (male or female, 1.5–2.5 months, 20–25 g) by intraperitoneal injection (i.p.) of a mixture of ketamine (17.2 mg/mL), xylazine (0.475 mg/mL) and acepromazine (0.238 mg/mL) (6 µL/g body weight). Wait until the proper depth ....

Results

Figure 1. Creation of bilateral windows on the skull. (A) A photographic image shows 2 cranial optical windows on each side of the skull overlying the S1 area. (B) High magnification of the boxed region of the image (A) showing bilateral optical windows .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
C57BL/6J-Tg(Thy1-GCaMP6s)GP4.3Dkim/J	Jackson	24275	Can be any strains made by the genetically-encoded neuronal indicator and effector expressing the green fluorescent calcium indicator, GCaMP, in subsets of excitatory neurons in the cortex.
B6.Cg-Tg(Thy1-EGFP)OJrs/GfngJ.	Jackson	7919	Can be any strains expressing EGFP in subsets of neurons within specific populations in the cortex; providing a bright, vital Golgi-like stain.
Dumont no. 5 forceps, standard, Dumoxel	Fine Science Tools	11251-30	Can be any brand of choice.
Dumont no. 5SF forceps	Fine Science Tools	11252-00	Can be any brand of choice.
Micro Bead Sterilizer	Southern Labware	B1201	Can be any brand of choice.
Harishige's SG-4N Head Holding Adaptor	Tritech Research	SG-4N	Can be any brand of choice.
Ideal Micro-Drill Complete Kit	Harvard Apparatus	72-6065	Can be any brand of choice.
Burrs for Micro Drill	Fine Science Tools	19007-05	Can be any brand of choice.
Round cover glass, 3 mm	Harvard Biosciences	W4 64-0720	Can be any brand of choice.
Round cover glass, 5 mm	Harvard Biosciences	W4 64-0700	Can be any brand of choice.
Norland optical adhesive	Norland Products	7106	Can be any brand of choice.
Loctite liquid super glue	WB Mason	LOC1647358	Can be any brand of choice.
Grip cement kit, powder and solvent	Dentsply	675570	Can be any brand of choice. Mix 5 parts of white dental cement powder (Grip Cement) with one part of black Tempera powder paint (to shield from light; some users prefer a 10:1 ratio).
Gel foam	Moore Medical	2928	Can be any brand of choice.
Micro dissecting scissors	Roboz	RS-5841	Can be any brand of choice.
Artificial cerebrospinal fluid (ASF)	-	-	The ACSF contains 125 mM NaCl, 4.5 mM KCl, 26 mM NaHCO3, 1.25 mM NaH2PO4, 2 mM CaCl2, 1 mM MgCl2 and 20 mM glucose. Bubble the ACSF with oxygen (95% oxygen, 5% carbon dioxide) and adjust the pH to 7.4. Prepare fresh ACSF solution before every experiment.