Implanting a Wireless Bidirectional Microelectrode System in a Rat Brain

Secure an anesthetized rat on a stereotactic frame with a heating pad.

Shave and sterilize the surgical site.

Inject anesthetics and make an incision.

Separate the skin and remove tissue, exposing the skull.

Drill holes in the skull and fix the screws.

Drill a hole above the target brain region and clean it. 

Assemble a wireless microelectrode unit connected to the preamplifier to record and stimulate neural activity. This assembly is attached to the micromanipulator.

Vertically insert the microelectrode unit until the electrode tips reach the target region.

Position the ground cable appropriately to reduce electrical noise.

Adjust electrode placement until high-quality neural signals are obtained.

Secure the microelectrode unit using UV glue.

Cover the screws, cables, and contact plate with resin.

Remove the rat from the stereotactic frame and detach the preamplifier from the microelectrode unit.

Cover the implanted microelectrode unit using a protector.

Allow the rat to recover.

To begin this procedure, fix and horizontally align the animal's head in the stereotactic apparatus using ear bars and upper incisor bar. Next, shave the surgical field using surgical clippers or scissors, and sterilize the scalp with povidone-iodine.

Place a heating pad under the animal to prevent hypothermia and treat its eyes with dexpanthenol to prevent them from drying. Then, inject xylocaine in the center of the surgical site. Afterward, make a small incision with a scalpel to expose the skull. Separate the skin gently and remove residual tissue.

Next, carefully clean the skull using hydrogen peroxide-coated cotton buds. Subsequently, drill four small holes in the skull for fixation of stainless steel screws. Following that, drill a hole approximately 7 millimeters in the skull above the target area for fixation of the electrode unit.

Connect the microelectrode unit and electrode holder to the preamplifier which is attached to the stereotactic micromanipulator. Absorb any blood with cotton buds. Then, vertically introduce the microelectrode unit until the electrode tips reach the target area.

Position the ground cable along the stainless steel screws and under the skin. After that, carefully adjust the electrode with the micromanipulator until it reaches a zone of active neurons in the target structure. In the meantime, monitor the spike activity and detect neural activity with a signal-to-noise ratio suited for spike sorting.

Next, fix the microelectrode unit to the skull with ultraviolet glue. Cover the screws and the ground cable with acrylic resin. After that, disconnect the microelectrode unit from the electrode holder. Cover the contact plate and small cables with acrylic resin.

Carefully remove the rat from the stereotactic frame and disconnect the preamplifier from the microelectrode unit. Then, connect the cap protection on the microelectrode unit implanted and disconnect it only during the experimental procedures.