Recording Neural Activity in Freely Moving Mice Using Fiber Photometry

Begin by inspecting the distal end of the fibers of the patch cord by eye, and with a mini fiber microscope. If the surface of the fibers is scratched, repolish the fibers using fiber polishing film with fine grit. Then, clean the distal ends of the patch cord with 70% ethanol and a cotton-tip applicator. Clean the fiber optic cannulas using 70% ethanol and a cotton-tip applicator.

Connect the ferrule end of the patch cord to the implanted fiber using a ceramic split sleeve covered with a black shrink tube. During the connection, make sure that the sleeve is tight. Allow the animal to recover for a few minutes, then, start recording the optical signal and run the experiment. While recording, keep a careful eye on the live trace to ensure quality recordings, and watch for any jumps in signal indicating the sleeve is not tight enough.