Control of swimming in crucian carp: Stimulation of the brain using an implantable wire electrode

Control of locomotion in different kinds of animals, or so-called bio-robot, has been reported. Bio-robot is a technology based on the information communication between the nerve tissue and the computer. In this work, to study the locomotion control in carp´s brain, a Parylene-based wire microelectrode is fabricated for stimulation in midbrain. Compared with traditional microelectrodes, wire electrodes provide better bio-compatibility and good mechanical stability. The whole electrode was covered by Parylene C film, except the stimulation sites which are exposed by lift-off process, thus the interface impedance is significantly reduced. After the fabrication, crucian carps was anesthetized in MS-222 water solution and the cranium was partially removed to expose the midbrain. After all these steps, electrodes are tested to see if they are properly insulated. Then one electrode is implanted into the crucian carp´s midbrain by surgical procedure and the movement of the fish is observed by a video camera. The caudal fin movement of crucain carp is successfully induced by applying a single polar pulse train. This result proved the former theory that control region of carp is located in midbrain. On the other hand, the experiment shows great potential and promising future in the bio-robotic fish.