After securing the anesthetized animal in the stereotaxic apparatus, trim away the scalp along the edge of the skull. Then wipe the skull surface with 75%alcohol to expose the positions of the bregma and lambda. Using a micro drill, level the mouse and drill holes above the regions of interest.
Then inject the relevant viruses with a syringe pump. Now hold the optrodes with a holder and move their tip to the bregma point, setting this position as zero. Using the bregma point as the reference coordinate, move the optrodes to the target regions.
Position the optrodes 0.3 millimeters above the virus injection site. After inserting the optic fibers into the corresponding brain areas, apply a small amount of tissue adhesive around them to cover the exposed tissue. Sequentially apply additional adhesive and a little dental cement.
After the dental cement solidifies, release the holder carefully. Once all erodes are implanted, drill the holes behind the lambda point for ground and above the neocortex for EEG using a micro drill. Insert skull screws into the hole above the cortex and behind the lambda point.
Then organize the tungsten and enameled wires so they are positioned above the implantation area and not exposed outside the skull. Secure the position of the female connector using a holder. Now fill the implantation site with dental cement to ensure a stable connection between the electrode device and the skull.
Encapsulate the internal wires, leaving the female connector's insertion holes exposed for connection to the head stage. Once the dental cement hardens, apply iodine to the wound and place the animal on a warming pad.
