Surgical Procedure

	Anesthetize a monkey and fix the head on stereotaxic. Attach all of electrode for monitoring vital signal during surgery. Disinfect all of surgical area and cover the area with sterilized drapes.
	Incise a skin with a cautery knife. The galea aponeurotica is cut at the center and gently peeled off from skull with the knife.
	The galea aponeurotica and temporal muscle are removed from skull with scraper until all of surgical area is exposed. Tissues on skull surface have to be wiped out and all of bleeding has to be completely stopped.
	Edge of the skin and the muscles are wrapped with moistened gauze. The gauze has to be kept moistened during the surgery.Traction sutures are put at skin edge under the gauze and the suture is pulled out to ensure a sufficient working space. Drawing a planned area of craniotomy on the skull with a pencil. Circle is where burr hole will be put and lines are where craniotome will cut the skull.
	Titanium screws are implanted as an anchor for fixing a connector on the skull. This can be done after completing ECoG implantation, but it might be safer to do before craniotomy.
	Burr holes are made with a perforator. The perforator has to be placed perpendicular to the bone surface and should not stop or pull out until the drill stops. It stops automatically when it penetrates the bone. During drilling the bone, drop a saline at the hole with syringe for cooling and washing out drilled bone.
	At the bottom of burr hole, there is a very thin bone flap left. Remove the flap carefully with curette.

Surgical illustrations courtesy of [Juna Kurihara]