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The drive mechanism is made from two principal parts: The static guide tubes that define the spatial pattern of electrodes, and the mobile shuttle tubes that move within the guide tubes. The tubes are made from pieces of polyimide tubing.
Each electrode (or electrode bundle) is inserted through a shuttle tube and glued at the top so it moves through the guide tube when the shuttle tube is lowered in its guide tube.
(The picture shows the shuttle tube extending almost all the way through the guide tube - this can increase the friction of the drive and cause problems. It is often better to keep the shuttle tubes as short as possible, so they stop short of the bend in the guide tube when the drive is fully lowered.)
The linear motion that drives the electrodes is provided by the 16 arms of a single steel spring that are each held down by an adjustment screw. Each shuttle tube is attached to one of the arms of the spring. By turning the screw, the spring arm is either pressed down or released, which translates to a linear motion of the shuttle tube within the guide tube, moving the electrode in the brain. Each full turn of a screw corresponds to ~250μm in electrode motion.
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