Disclaimer: These protocols are intended as a guide for familiarization with the device and system.
Surgical and animal welfare guidelines vary by institution. Please consult your institution's veterinary professional
to ensure compliance with local regulations and protocols.
Purpose: This procedure specifically details the surgical implantation of electrodes for EEG recordings in mice and rats using either our SCT or HMT devices. This protocol does not cover the complete surgical procedure for transmitter implantation.
At this time, this protocol does not include EMG electrode implantation, if you are interested in using our sysetm to record EMG, you can view our draft EMG implantation protocols, or email us for details.
page-chunkmatch-prompts-onlyElectrode implantation for EEGWhat is the procedure for implantaing eletrodes in an animal?Surgical protocol for depth electrode implantation?
Our Depth Electrodes allow for a deeper reach into the brain. The insulated wire in the electrode will bve delivered either in the standard length or in a length specified by the you. You can cute the wire back to any length yourseld, either with a square cut or at an angle for better penetration. Each electrode provides a mounting fixture by which we can hold the electrode during surgery.
J-Electrode
Figure: J-Electrode
Details: The J-Electrode is a depth electrode equipped with a teflon-insulated, full-hardened 316 stainless steel wire. The wire is held in place during implantation by a guide canula within a pedastal. The advantage of the J-Electrode over the X and W-Electrodes is the ease with which we can cut the J-Electrode wire and remove the guide, but can result in chemical artifacts. Do not use the J-Electrode to record cortical spreading depressions (CSDs).
Stereotaxic apparatus with attachment to hold the metal electrode tube
Directions
Trim the insulated electrode wire to the desired length, based on the recording depth.
Secure the J-Electrode by its cannula guide in a clamp above the animal’s head, mounted to a stereotaxic instrument for steady insertion.
Connect the D-Pin lead to the electrode socket.
Lower the electrode into the burr hole to the target depth.
Seal the socket and burr hole with Vetbond adhesive followed by dental cement, or with cement alone. Avoid covering the cannula.
After the cement cures, cut the bare steel wire where it emerges from the cannula pedestal.
Lift the cannula off the wire.
Cut the wire flush with the cement surface and cover the exposed tip with additional cement.
R-Electrode
Figure: R-Electrode
Details: The R-Electrode is a depth electrode equipped with a teflon-insulated, full-hardened 316 stainless steel wire as well as a guide cannula for repeated administration of a substance to the brain. The wire and cannula are held in place by a threaded pedastal. The pedastal remains on the animals head throughout the experiment. The R-Electrodes socket-pin connection allows for an easier surgical implantation, but can result in chemical artifacts. Do not use the R-Electrode to record cortical spreading depressions (CSDs).
Stereotaxic apparatus with attachment to hold the metal electrode tube
Directions
The R-Electrode includes both a cannula for injections and a depth electrode wire. Drill a burr hole large enough for both components.
Trim the insulated electrode wire to the desired length. Optionally, cut at an angle for easier penetration.
Secure the R-Electrode by its cannula guide in a stereotaxic clamp above the animal’s head.
Connect the D-Pin lead to the E-Socket using tweezers. Customized orientations are available upon request.
Check the connection by gently tugging near the socket-pin junction.
Lower the electrode and cannula into the burr hole.
Cover the base of the electrode and the burr hole with dental cement.
Attach the dummy cap to the R-Electrode when not injecting.
W-Electrode
Figure: W-Electrode
Details: THe W-Electrode is a depth electrode equipped with a teflon-insulated, full-hardened 316 stainless steel wire. The wire is held in place by a Depth Tube. This electrode is ideal for EEG recordings deeper in the brain. The W-Electrodes socket-pin connection allows for an easier surgical implantation, but can result in chemical artifacts. Do not use the W-Electrode to record cortical spreading depressions (CSDs).
Stereotaxic apparatus with attachment to hold the metal electrode tube
Directions
Trim the insulated electrode wire to the target length. Optionally, cut the tip at an angle for easier penetration.
Note: The W-Electrode has a post that must be cut above the socket and pin connection after implantation. Practice beforehand to reduce shaking.
Secure the W-Electrode by its cannula guide in a stereotaxic clamp above the head.
Insert the D-Pin lead into the E-Socket on the W-Electrode.
Confirm the crimp contact is secure by gently pulling the lead.
Lower the electrode into the burr hole to the desired depth.
Cut the metal post carefully at the thinned section above the socket.
Cover the electrode and socket area with dental cement.
X-Electrode
Details: THe X-Electrode is a depth electrode equipped with a teflon-insulated, full-hardened 316 stainless steel wire. The wire is held in place by a Depth Tube. This electrode is ideal for EEG recordings deeper in the brain. The X-Electrodes crimp contact does not contain any solder, so the signal recorded by the electrode will contain far less low-frequency chemical artifacts. Crimp contacts allow us to record slow signals like cortical spreading depressions (CSDs).
Stereotaxic apparatus with attachment to hold the metal electrode tube
Directions
Trim the insulated electrode wire to the target length. Optionally, cut the tip at an angle for penetration.
The X-Electrode has a post that must be cut after implantation. Practice the cut beforehand to avoid shaking.
Secure the X-Electrode in a stereotaxic clamp above the head.
If the B-lead is unstripped, expose 1.5–3 mm of coil at the tip (3 mm preferred). See Lead Stripping for guidance.
Hold the B-lead ~5 mm from the coil and slide the Q-ferrule on, keeping it near the X-Electrode.
Ensure ~4 mm of stripped X-Electrode wire is available for the crimp.
Guide the coil and Q-ferrule over the X-Electrode wire so the wire passes through the coil center.
Position the ferrule to overlap both coil and stripped wire.
Video: X-Electrode and B-Lead Crimp Connection with Q-Ferrule.
Crimp firmly with pliers to secure.
Test the crimp by gently pulling the lead.
Cover the electrode and socket with dental cement (optionally add Vetbond adhesive first).
Cut the X-Electrode post at the thinned section and seal any exposed metal with cement.
Surface Electrodes
Figure: Angled Wire Electrode, held in place by a fastening screw.
Coiled Wire
Note: Coiled wire electrodes use a helical bare wire tip. Straighten them prior to implantation. These electrodes are ideal for recording from te surface of the brain.
Figure: A-Coil wire termination at the end of a B-Lead
Straighten the bare coiled wire carefully with tweezers, avoiding tension on the lead.
Create a 90° bend at the midpoint of the bare wire.
Trim the bent section so it matches skull thickness plus desired cortical depth.
Test screw fit in burr holes; holes should be slightly smaller for a snug fit.
Insert the electrode into the burr hole, securing it with tweezers.
Leave a short section of exposed wire atop the skull (before the bend) to prevent screw contact with insulation.
Optionally apply semi-cured Vetbond to the wire on the skull (avoid the burr hole) to stabilize before screwing.
Insert the screw into the burr hole, ensuring the electrode does not bind in the threads.
Cover the screw and exposed wire with dental cement to insulate and reduce EEG artifacts.
Notes
Ensure cement is fully dry before closure.
Position screws several millimeters away from insulated lead sections.
Screws must avoid muscle contact.
Straightened Wire
Details: Straightened wire electrodes use a silicone coated wire with a bare wire tip. Straighten them prior to implantation. These electrodes are ideal for recording from te surface of the brain.
Trim the bent section to match skull thickness plus target depth.
Test screw fit in burr holes for snug engagement.
Insert the electrode into the burr hole while securing with tweezers.
Leave a small section of exposed wire atop the skull to isolate from the screw.
Optionally apply semi-cured Vetbond on the skull surface for stability, avoiding the burr hole.
Screw into the burr hole without trapping the electrode in threads.
Seal with dental cement to insulate and reduce artifacts.
Screw Electrodes
Details: Screw electrodes are a fastening screw soldered to a helical subcutaneous lead. Screw electrodes are ideal for recording from the surface of the brain and allow for a secure implantation. Do not use for the measurement of cortical spreading depressions (CSDs).
Electrode Surgical Implantation Protocol
