To prepare an omega-shaped head bar for the zebrafish head restraint, attach a piece of oil-based modeling clay to a three-axis micro manipulator. Then insert an arm of the head bar into the clay and orient the head bar horizontally. Prepare the cannon for holding the fish's body in place during surgery.
To remove excess skin and water from the skull's attachment sites, prepare four tissue swabs by cutting a paper towel into a three centimeter square. Then fold the paper squares along their diagonal to produce a tube-like structure and twist the ends of the tube into a fine point. After anesthetizing the fish with 0.03%TMS, perform syringe perfusion with 0.01%TMS to maintain sedation throughout the procedure.
Wrap the fish in moist paper tissue starting from the tip of the tail to around one millimeter caudal to the gill. Then wrap a soft plastic tubing with a longitudinal slit around the paper tissue covering the fish from the end of the tail to around two millimeter caudal to the gill. Wrap the paper towel around the tubing.
Then wrap a soft plastic tube cut from the bulb of a plastic transfer pipette around the paper towel. Load the wrapped fish into the cannon. Next, using a scalpel, remove the skin covering the attachment sites, two triangular areas of the skull rostrolateral to the cerebellum and above the gills.
Then use tissue swabs to dry the attachment sites and clear any remaining skin. Using a 10 microliter pipette tip, apply a drop of tissue glue at the center of each attachment site. Place the fish body in an upright position and position the head bar slightly above and caudal to the attachment sites.
Next, prepare dental cement by mixing one small spoon of polymer with four drops of quick monomer and one drop of catalyst five. Stir the mixture evenly for 15 seconds. Immediately after mixing, use a micropipette and a 10 microliter pipette tip to apply the cement onto the attachment sites and the region between the sites.
Then using a micro manipulator, gently press the head bar onto the cement. Cover the head bar with the remaining cement and wait for 12 minutes to allow the curing of the cement. Next, to improve optical access to the forebrain for calcium imaging, use a scalpel to remove the skin above the telencephalon.
After curing, remove the clay from the head bar. Next, prepare a fish loading module for the micro manipulator. Then transfer the entire capsule from the cannon to the pitch adjuster in the fish loading module.
Using the micro manipulator, position the fish with the head bar placed on top of the metal posts of the head stage. Slightly increase the pitch angle of the fish. Apply ultraviolet curable glue to secure the head bar to the metal posts.
Then pull out the fish from the capsule and lock the head stage onto the base plate within the semi hexagonal tank. After surgery, immerse the animal in fish tank water to recover from anesthesia.
