We would like to thank Helmut Scheu for the opportunity to conduct our research in the pigpen at Hofgut Neum&#252;hle.

All procedures were approved by the local ethics committee (#23177-07/G10-1-010/G 15-15-011) and followed the European and the German national regulations (European Communities Council Directive, 86/609/ECC; Tierschutzgesetz).
All animal procedures were performed in accordance with the Medical Center of the Johannes Gutenberg-University Mainz animal care committee&#39;s regulations.
1. Setup
<ol>
	<li>Prior to the experiment, check for any line noise and find an a...

<ol>
	<li>Conrad, M. S., Sutton, B. P., Dilger, R. N., Johnson, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vivo+three-dimensional+magnetic+resonance+imaging-based+averaged+brain+collection+of+the+neonatal+piglet+(Sus+scrofa).">An in vivo three-dimensional magnetic resonance imaging-based averaged brain collection of the neonatal piglet (Sus scrofa).</a> PLoS ONE. 9 (9), e107650 (2014).</li><li>de Camp, N. V., Hense, F., Lecher, B., Scheu, H., Bergeler, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Models+for+preterm+cortical+development+using+non+invasive+clinical+EEG.">Models for preterm cortical development using non invasive clinical EEG.</a> Translational Neuroscience. 8, 211-224 (2017).</li><li>Lapray, D., Bergeler, J., Dupont, E., Thews, O., Luhmann, H. J., Barculo, D., Daniels, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+telemetric+system+for+recording+brain+activity+in+small+animals.">A novel telemetric system for recording brain activity in small animals.</a> Telemetry: Research, Technology and Applications. , 195-203 (2009).</li><li>Kim, D., Yeon, C., Kim, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+experimental+validation+of+a+dry+non-+invasive+multi-channel+mouse+scalp+EEG+sensor+through+visual+evoked+potential+recordings.">Development and experimental validation of a dry non- invasive multi-channel mouse scalp EEG sensor through visual evoked potential recordings.</a> Sensors. 17, 326 (2017).</li><li>Moshayedi, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relationship+between+glial+cell+mechanosensitivity+and+foreign+body+reactions+in+the+central+nervous+system.">The relationship between glial cell mechanosensitivity and foreign body reactions in the central nervous system.</a> Biomaterials. 35, 3919-3925 (2014).</li><li>Barrese, J. 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A critical step in the protocol is the adequate skin contact with the electrodes, especially the ground electrode, to achieve stable recordings with low noise. Furthermore, since piglets are very agile, it is important to cover the whole system with silicone rubber to protect the electrodes and the telemetry unit. Furthermore, if the experiments are conducted in a stable with a slatted floor, be cautious with small devices or connectors.
In case of an inadequate grip of the self-adhesive hydro...

Piglets are an emerging model system for neuroscience1. In order to strengthen translational research, we invented a method to record non-invasive, clinical EEGs from unrestrained piglets2 (Figure 1 and Figure 2). Two prerequisites for a translational use of EEG recordings, regarding EEG patterns associated with cortical maturation, are a non-invasive methodology, comparable to the clinical setting, and the abstinence of sedatives or anesthesia. The one-channel telemetry system3 in combination with self-adhesive electrodes can be fixed in about 5 min. Afterward, the piglets will recover quickly from the handling procedure and synchronize their feeding and sleeping behavior to that of the other piglets and the sow.
Even though there are already attempts to use non-invasive EEG recordings from sedated animals4, most electroencephalography studies from animals are conducted with invasive approaches. These methods have side effects regarding inflammatory processes around the implanted electrodes5,6 and, in most cases, they require a social separation of the animals due to the external components of the implanted EEG system. Hence, the translation of these data to the clinical context is difficult. The need for translational approaches is becoming clear by the fact that it is still not known how a &#34;normal&#34; brain maturation during the early cortical development is represented by clinical, non-invasive electroencephalography7. This knowledge gap is caused by technical challenges associated with EEG recordings from preterm babies8. In animal model systems, patterns of early cortical development are better accessible, since most animals are born with a &#34;preterm brain&#34; in comparison to human cortical development9. Besides conserved patterns of cortical development across species2, it has recently been shown that EEG recordings from preterm babies can also predict the individual clinical outcome during later life10,11. The method described here is especially useful for the translational aspects of developmental neuroscience.

<table border="0" cellpadding="0" cellspacing="0" width="867">
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Disposable adhesive 
			surface silver/silver chloride electrodes</td>
			<td style="width:309px;">Spes 
			Medica S.r.l., Genova, Italy</td>
			<td style="width:119px;"></td>
			<td style="width:223px;">Self adhesive hydrogel electrode</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Abralyt HiCl</td>
			<td style="width:309px;">Easycap GmbH</td>
			<td style="width:119px;"></td>
			<td>Abrasive cream</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Body Double fast</td>
			<td style="width:309px;">Smooth On Inc.</td>
			<td style="width:119px;"></td>
			<td>Skin adhesive silicone</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Telemetry system</td>
			<td style="width:309px;"></td>
			<td style="width:119px;"></td>
			<td>Internal development</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Picolog 1216</td>
			<td style="width:309px;">Pico Technology</td>
			<td style="width:119px;"></td>
			<td>AD converter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laptop</td>
			<td style="width:309px;">Panasonic</td>
			<td style="width:119px;"></td>
			<td>Rugged laptop</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Receiver</td>
			<td style="width:309px;"></td>
			<td style="width:119px;"></td>
			<td>Internal development</td>
		</tr>
	</tbody>
</table>

noninvasive eeg recordings from freely moving piglets

The method allows the recording of high-quality electroencephalograms (EEGs) from freely moving piglets directly in the pigpen. We use a one-channel telemetric electroencephalography system in combination with standard self-adhesive hydrogel electrodes. The piglets are calmed down without the use of sedatives. After their release into the pigpen, the piglets behave normally&#8212;they drink and sleep in the same cycle as their siblings. Their sleep phases are used for the EEG recordings.

We were able to record typical EEG patterns associated with non-REM sleep, like spindle bursts or delta brushes, from freely moving piglets (Figure 1 and Figure 2). We were mostly interested in representative patterns during non-REM sleep, but phases of REM-like sleep12 with a very low amplitude have also been recorded (Figure 3). The physiology and the amount of REM sleep dif...

Watch this Scientific Journal Video about Noninvasive EEG Recordings from Freely Moving Piglets at JoVE.com

Noninvasive EEG Recordings from Freely Moving Piglets

Here, we present a protocol to record telemetric electroencephalograms (EEGs) from freely moving piglets directly in the pigpen without the use of a sedative, making it possible to record typical EEG patterns during non-REM sleep, like spindle bursts.

The method allows the recording of high-quality electroencephalograms (EEGs) from freely moving piglets directly in the pigpen. We use a one-channel ...

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.

Noninvasive EEG Recordings from Freely Moving Piglets

Abstract