To begin, use an intraperitoneal anesthetized mouse and expose the skull Using standard surgical procedures. Attach the stainless steel rod mounted to the 2D electrode array on the backside of the flexible substrate to a manipulator. Then place the flexible substrate on the exposed skull.
Adjust the location of channels 3 and 14 on the array to fit within the inferior colliculus. Draw four small circles at the locations of channels 3, 8, 9, and 14 on the skull with a permanent marker to serve as targeting landmarks. Next, dry the skull surface to improve the adherence of the dental cement and to electrically isolate the 2D electrode array on the flexible substrate from the mouse skull.
Apply a layer of dental cement to the skull surface approximately one millimeter thick and allow the cement to cure for approximately 30 minutes. Align the flexible substrate in line with the small circular marks on the surface of the skull. Then position the tip of a dental drill on each electrode pad hole on the flexible substrate and carefully drill into the skull.
Using a screwdriver, secure the miniature screw electrodes into the drill holes of the skull. Crimp the head of the screw electrode and the electrode pad firmly. Finally, measure the conductance between each screw electrode and the connector with testing equipment, such as an LCR meter to confirm electrical conductivity.
