Implanting an Electrode Array and Optic Fiber into the Mouse Hippocampus

Take an immobilized anesthetized mouse with its skull exposed.

Drill holes rostral to the coronal suture and above the cerebellum.

Insert stainless-steel screws into the drilled sites rostral to the coronal suture for implant stabilization.

Insert the ground and reference screws above the cerebellum to minimize electrical noise.

Cover these screws with cement to prevent muscle artifacts during the recordings. Secure the other screws with cement.

Drill holes in the skull, exposing the hippocampal tissue. Apply saline to maintain tissue hydration. 

Lower the optic fiber and electrode array through the holes into the hippocampus for optical stimulation and targeted neural activity recording.

Apply warm wax around the implantation site to protect the tissue.

Encase the implant and skull in cement to stabilize them.

Solder the ground and reference wires to the electrode array to ensure a stable electrical connection.

Cover the wires with cement.

Return the mouse to its cage for recovery.