Prepping Conscious Rabbit Model for Simultaneous Video-EEG-ECG-Oximetry-Capnography for Experimental Interventions: A Procedure to Implant EEE-ECG Electrodes and Attach Respiratory Probes in Rabbit Model

Begin with a rabbit model in the supine position. Secure color-coded electrocardiography or ECG electrodes in the subcutaneous tissue, appropriately from the forelimbs and hindlimbs for accurate measurement of the electrical activity of the heart. The ground electrode minimizes noise interfering with ECG signals.

Restrain the rabbit in an appropriately-sized chamber to facilitate recordings in its conscious state. Insert electroencephalography or EEG electrodes into the subcutaneous tissue in the designated positions from the four quadrants of the head, reducing muscle artifacts during the electrical activity measurement of the brain. The ground electrode eliminates electrical noises from the EEG signals.

Attach a pulse oximeter to the rabbit's ear over its marginal ear vein. Secure a capnography mask over its mouth and nose. Connect the capnography mask and oximeter to the vital signs monitor to assess the carbon dioxide concentration and oxygen saturation level respectively in the animal.

Position the video camera to be within the view of the chamber. Connect the EEG and ECG electrodes to the biosignal amplifier, which in turn is connected to the data-acquisition system.

Using suitable software, perform the video-ECG-EEG recording to correlate motor activity with the electrical activity measurements of the brain. Start the baseline recordings until the signals stabilize. The prepped rabbit is ready for the intended experiment.

For implantation of the ECG electrodes, secure a rabbit in the supine position with the head at the investigator's knees and lower than the rest of its body. With a second investigator spreading the fur to expose the underlying skin, subdermally insert 35-degree angle bent electrodes into each axilla. Place leads on the chest, posterior to the right and left forelimbs, and on the abdomen, anterior to the left hind limb. Then, place a ground pin-electrode anterior to the right hind limb on the abdomen.

When all of the ECG leads have been properly placed, secure the rabbit in an appropriately-sized restrainer, with the hind limbs under the animal. Using a 45-degree angle approach, insert subdermal straight pin-electrodes into the scalp.

Place one EEG lead on the right anterior, left anterior, right occipital, and left occipital regions of the head, and place a central reference lead at the central point between the other four leads. Run the wires between the ears, and loosely tether them to the restrainer behind the head.

To monitor respiration during the experiment, attach a pulse oximeter to one ear over the marginal ear vein, and gently secure a face mask with capnography tubing over the mouth and nose of the animal. Then, attach the other end of the tubing to the vital signs monitor.

To record video EEG ECG, open an appropriate commercially available EEG software program, and adjust the video such that all of the rabbits can be observed within the field of view. Perform a baseline recording for the animal for a minimum of 10 to 20 minutes or until the heart rate stabilizes to 200 to 250 beats per minute for at least five minutes. Set the low-frequency filter to 1 Hertz and the high-frequency filter to 59 Hertz.

Add time-locked notes in real-time to indicate the timing of interventions, neurocardiac events, and motor or investigator artifacts.