Noninvasive EEG Recordings from Freely Moving Piglets

This method can help answer key questions in the neuroscience field about cortical development. The main advantage of this technique is that the animals do not need to be sedated. In general individuals new to this method will struggle because the animals are handled when they are awake and the experimenter must work quickly.

Before beginning the experiment, find an adequate location for the setup. Use a cable drum to supply the setup with line power, and connect the laptop, receiver unit, and analog to digital converter as necessary for the specific telemetry system being used. Place the electrodes, adhesives, cotton swabs, wipes, mixing blocks, sandpaper and abralate on a separate space, and cut and solder the electrodes to as short a length as possible, according to the size of the animal.

The cables must be long enough to connect from the recording electrode positions on the animal’s head with the telemetric EEG unit for the data transmission. When all of the materials are ready, catch a piglet at the leg or thorax taking care to be aware of any potential defecation or urination. Mark the piglet with a number as necessary, and wrap the animal in a towel to calm it down.

Holding the piglet with one hand at the body or forearm and using the other hand to control the snout, have an assistant clean the animal’s skin, using an appropriate tool to remove any dead skin as necessary. Place the recording electrodes at the appropriate experimental locations. The ground electrode above the cerebellum and the reference electrode on the snout.

When all of the electrodes have been placed, connect the cables to the telemetry unit and turn it on. Cover the telemetry unit, cables and electrodes with two component skin adhesive silicone rubber, when the silicone rubber is completely cured, place the piglet back into the pen and monitor the animal for several more minutes for any signs of discomfort. Before beginning the experiment check for any line noise, the piglet should recover and begin synchronizing its behavior with its siblings after about 30 seconds.

Wait for a sleep phase and begin the recording, gently moving any sleeping siblings from the telemetry unit as necessary. At the end of the recording period, catch the piglet again without aggravating the sow, and gently lift the silicone rubber at one edge, then remove the whole patch of silicone rubber containing the electrodes and the telemetry unit, being careful with the piglet’s eyes, and returning the piglet to the pen. Using the telemetry unit as demonstrated, EEG patterns associated with non-REM sleep, like spindle bursts or delta brushes can be captured from freely moving piglets as well as phases of REM-like sleep with very low amplitude.

A good quality recording can also be achieved during lactation. The message is also potentially useful for the assessment of animal welfare. After its development this technique paved the way for researchers in the field of developmental neuroscience to explore EEG patterns in awake animals.