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 adequate location for the set-up and the antenna. Line noise is visible as a 60 or 50 Hz sine wave. 
	NOTE: The placement of the antenna and especially the distance between the transmitter and the receiver depends on the transmission strength of the system. The system used here is adjustable. It was adjusted to a relatively low power, with an approximately 3 m transmission range. Additionally, the metallic fences in the pigpen can dampen the signal and cause interferences. In this case, it is necessary to place the antenna inside the metal cage.</li>
	<li>Use a cable drum to supply the set-up with line power. Connect the laptop, the receiver unit, and the analog-to-digital converter (if necessary) for the specific telemetry system that is being used. 
	NOTE: The telemetry system used here sent digital data to the receiver. This might be different for other systems.</li>
	<li>Place the electrodes, the adhesives, the Q-tips, and the wipes, as well as the mixing blocks, on a separate table.</li>
	<li>Prepare the electrodes with short cables. To do so, cut the electrodes and solder them again with a length as short as possible, depending on the size of the animal. The cables must be long enough to connect the desired recording positions on the head with the telemetric EEG unit, transmitting the data. Cables that are too long must be recoiled and covered with skin adhesive silicone elastomer. Longer cables that must be recoiled make the silicone patch bigger and heavier.</li>
</ol>
2. Piglet
<ol>
	<li>Catch a piglet by grabbing it at the leg or at the thorax. Hold it and be aware of any defecation or urination.</li>
	<li>If necessary, mark the piglet with a number.</li>
	<li>Wrap the piglet in a towel. The piglet will calm down. Be aware of overheating the piglet.</li>
	<li>Hold the piglet with one hand at the body or forearm. Use the other hand to hold the snout. Be aware of overheating the piglet and make sure it is free to breathe properly.</li>
</ol>
3. Electrodes
<ol>
	<li>Have a second person attach the electrodes.</li>
	<li>Clean the skin from dirt with water or ethanol. If necessary, shave the head.</li>
	<li>Remove any dead skin cells with an abrasive EEG gel and a Q-tip. Remove the abrasive gel afterward. Alternatively, use sandpaper.</li>
	<li>Fix the self-adhesive electrodes at the desired location. Place the ground electrode above the cerebellum (between the ears) and the reference electrode on the nose. Place the recording electrode at the desired location. 
	NOTE: In this case, a unipolar recording was performed, because the reference was placed at a neutral position (nose). There is no standardized system available for piglets until now. Here, a parietal recording position was used (between the eye and the ear) on the right brain hemisphere.</li>
	<li>Connect the cables to the telemetry unit. Turn the unit on. Depending on the telemetry system used, this might be a magnetic switch or a radio frequency wake-up signal.</li>
	<li>Cover the telemetry unit and all cables as well as all electrodes with two-component skin adhesive silicone rubber (see Table of Materials). By mixing equal amounts of both components, the curing time will be in the range of 1 min. Eyes and eyelashes should not be covered with the rubber.</li>
	<li>Wait until the silicone rubber is completely cured.</li>
	<li>Place the piglet back in the pigpen.</li>
	<li>Observe the piglet to see if it is showing signs of discomfort over a longer period of time (several minutes).</li>
</ol>
4. Measurement
<ol>
	<li>Wait until the piglet has recovered and starts to synchronize its behavior with that of its siblings (feeding, playing, sleeping), usually after 30 s (Figure 1).</li>
	<li>Wait for sleep phases, if desired. The recording time depends on the specific scientific question. Here, 10 min recording sessions were used.</li>
	<li>If the telemetry unit is covered by more than 2 other piglets, the signal might be too low for the receiver. Gently push the piglets away if they are sleeping on top. Be aware of the sow; it might react aggressively.</li>
	<li>Start the recording with the data acquisition software (see Table of Materials).</li>
</ol>
5. Finish
<ol>
	<li>After the recording (usually several hours), catch the piglet again as has been described in step 2. Be aware of the sow; it might react aggressively.</li>
	<li>Gently lift the silicone rubber at one edge. Then, remove the whole patch of silicone rubber containing the electrodes and the telemetry unit. Be careful with the piglet&#39;s eyes.</li>
	<li>Place the piglet back in the pigpen.</li>
</ol>

<ol><li>Conrad, M. S., Sutton, B. P., Dilger, R. N., Johnson, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+in+vivo+three-dimensional+magnetic+resonance+imaging-based+averaged+brain+collection+of+the+neonatal+piglet+%28Sus+scrofa%29%5BTitle%5D)+AND+%22PLoS+ONE%22%5BJournal%5D)">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/pubmed?term=((Models+for+preterm+cortical+development+using+non+invasive+clinical+EEG%5BTitle%5D)+AND+%22Translational+Neuroscience%22%5BJournal%5D)">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. A novel telemetric system for recording brain activity in small animals. <a target="_blank" href="https://www.researchgate.net/profile/Oliver_Thews/publication/229035898_A_novel_telemetric_system_for_recording_brain_activity_in_small_animals/links/02e7e516666923d52e000000/A-novel-telemetric-system-for-recording-brain-activity-in-small-animals.pdf">Telemetry: Research, Technology and Applications</a>. Barculo, D., Daniels, J. , Nova Science Publishers. 195-203 (2009).</li>
<li>Kim, D., Yeon, C., Kim, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Development+and+experimental+validation+of+a+dry+non-+invasive+multi-channel+mouse+scalp+EEG+sensor+through+visual+evoked+potential+recordings%5BTitle%5D)+AND+%22Sensors%22%5BJournal%5D)">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/pubmed?term=((The+relationship+between+glial+cell+mechanosensitivity+and+foreign+body+reactions+in+the+central+nervous+system%5BTitle%5D)+AND+%22Biomaterials%22%5BJournal%5D)">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. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Failure+mode+analysis+of+silicon-based+intracortical+microelectrode+arrays+in+non-human+primates%5BTitle%5D)+AND+%22Journal+of+Neural+Engineering%22%5BJournal%5D)">Failure mode analysis of silicon-based intracortical microelectrode arrays in non-human primates.</a> Journal of Neural Engineering. 10, 066014(2013).</li>
<li>Hellström-Westas, L., Rosén, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Electroencephalography+and+brain+damage+in+preterm+infants%5BTitle%5D)+AND+%22Early+Human+Development%22%5BJournal%5D)">Electroencephalography and brain damage in preterm infants.</a> Early Human Development. 81, 255-261 (2005).</li>
<li>Lloyd, R. O., Goulding, R. M., Filan, P. M., Boylan, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Overcoming+the+practical+challenges+of+electroencephalography+for+very+preterm+infants+in+the+neonatal+intensive+care+unit%5BTitle%5D)+AND+%22Acta+Paediatrica%22%5BJournal%5D)">Overcoming the practical challenges of electroencephalography for very preterm infants in the neonatal intensive care unit.</a> Acta Paediatrica. , 152-157 (2015).</li>
<li>Clancy, B., Finlay, B. L., Darlington, R. B., Anand, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Extrapolating+brain+development+from+experimental+species+to+humans%5BTitle%5D)+AND+%22Neurotoxicology%22%5BJournal%5D)">Extrapolating brain development from experimental species to humans.</a> Neurotoxicology. 28, 931-937 (2007).</li>
<li>Iyer, K. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Cortical+burst+dynamics+predict+clinical+outcome+early+in+extremely+preterm+infants%5BTitle%5D)+AND+%22Brain%22%5BJournal%5D)">Cortical burst dynamics predict clinical outcome early in extremely preterm infants.</a> Brain. 138, 2206-2218 (2015).</li>
<li>Luhmann, H., de Camp, N., Bergeler, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Monitoring+brain+activity+in+preterms%3A+mathematics+helps+to+predict+clinical+outcome%5BTitle%5D)+AND+%22Brain%22%5BJournal%5D)">Monitoring brain activity in preterms: mathematics helps to predict clinical outcome.</a> Brain. 138, 2114-2125 (2015).</li>
<li>Dragomir, A., Akay, Y., Curran, A. K., Akay, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Complexity+measures+of+the+central+respiratory+networks+during+wakefulness+and+sleep%5BTitle%5D)+AND+%22Journal+of+Neural+Engineering%22%5BJournal%5D)">Complexity measures of the central respiratory networks during wakefulness and sleep.</a> Journal of Neural Engineering. 5, 254-261 (2008).</li>
<li>Peever, J., Fuller, P. M. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/29161567">The biology of REM sleep.</a> Current Biology. 27, R1237-R1248 (2017).</li>
<li>Robert, S., Dallaire, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Polygraphic+Analysis+of+the+sleep-wake+states+and+the+REM+Sleep+periodicity+in+domesticated+pigs+%28Sus+scrofa%29%5BTitle%5D)+AND+%22Physiology+%26+Behavior%22%5BJournal%5D)">Polygraphic Analysis of the sleep-wake states and the REM Sleep periodicity in domesticated pigs (Sus scrofa).</a> Physiology & Behavior. 37 (2), 289-293 (1986).</li>
</ol>

The authors have nothing to disclose.

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 hydrogel electrodes, try to remove the abrasive cream as much as possible. An alternative way to remove the outer dead skin layer is using sandpaper. A pretreatment with alcohol is not mandatory. Dirty skin can also be cleaned with water. Do not use plaster strips instead of body double silicone to fix the telemetric system. Plaster strips can cause skin irritation and massive signs of discomfort. Piglets get rid of the system very fast in that case.
A limitation of the method is the stability of hydrogel electrodes. They may dry after a few hours, resulting in a loss of recording quality. Furthermore, as with all EEG techniques, strong movements are usually associated with muscle artifacts on the recording trace (as seen in Figure 4). Additionally, a good placement of the antenna is important to reduce artifacts which may result from a poor receiver signal. Metal fences can also cause high-frequency interferences, resulting in a loss of data sequences. A solution for this issue is to place the antenna inside the metal fence in an optimal position. The optimal position of the antenna can only be evaluated in the field by trial and error. The sow and the other piglets do not lead to artifacts, because the piglets wearing the system usually do not allow other piglets to manipulate their head. This might be different for other species.
The method is especially significant for translational approaches in neuroscience. With this technique, it is possible to use non-invasive recordings without sedation. The resulting EEG recordings are very similar to the clinical setting. The technique might open up new possibilities to characterize preterm EEG maturation by means of animal model systems. Beyond that, many neuroscientific questions, especially regarding cortical field potentials, might also be examined by this noninvasive technique. Hence, the method has the potential to reduce the number and severity of animal experiments in the field of neuroscience.
For the future, recordings with more than one electrode are planned. A prerequisite is the miniaturization of the electrodes. Furthermore, the long-term stability of the electrodes is an issue for future innovations.

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><tbody><tr><td>Disposable adhesive&lt;br/&gt; surface silver/silver chloride electrodes</td><td>Spes&lt;br/&gt; Medica S.r.l., Genova, Italy</td><td></td><td>Self adhesive hydrogel electrode</td></tr><tr><td>Abralyt HiCl</td><td>Easycap GmbH</td><td></td><td>Abrasive cream</td></tr><tr><td>Body Double fast</td><td>Smooth On Inc.</td><td></td><td>Skin adhesive silicone</td></tr><tr><td>Telemetry system</td><td></td><td></td><td>Internal development</td></tr><tr><td>Picolog 1216</td><td>Pico Technology</td><td></td><td>AD converter</td></tr><tr><td>Laptop</td><td>Panasonic</td><td></td><td>Rugged laptop</td></tr><tr><td>Receiver</td><td></td><td></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 differ across species13. Short REM phases in the range of a few minutes are typical for pigs14. Good recording quality was also available during feeding (lactation) (Figure 4). As for playing behavior, strong muscle activity leads to muscle artifacts; however, filters have been designed to extract EEG bands. Further possible analytical tools are calculations of power spectral density or analytical tools focusing on network activity, as, for example, phase-amplitude coupling. These analytical tools can also be used with single-channel EEG recordings.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58226/58226fig1.jpg" /> 
Figure 1: A sleeping piglet with the telemetric EEG system. <a href="https://www.jove.com/files/ftp_upload/58226/58226fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/58226/58226fig2.jpg" /> 
Figure 2: Typical EEG patterns recorded during the sleep phase of a freely moving piglet, resting beside its siblings. Four events are highlighted by boxes. From left to right, the first box shows typical patterns elicited by muscle activity; for example, short twitches during sleep, characterized by high amounts of fast gamma activity (above 80 Hz) and a burst-like appearance. The second box shows a delta brush-like episode, characterized by delta activity with superimposed activity in the theta and alpha range. The third and fourth boxes show short episodes of gamma bursts (sleep spindle-like events), characterized by frequency components in the alpha, beta, and gamma bands. <a href="https://www.jove.com/files/ftp_upload/58226/58226fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/58226/58226fig3.jpg" /> 
Figure 3: REM phases during sleep. The first and the second box show slow-wave sleep phases. The third box indicates a low-amplitude EEG phase of approximately 20 s in duration. <a href="https://www.jove.com/files/ftp_upload/58226/58226fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/58226/58226fig4.jpg" /> 
Figure 4: A 10 min EEG recording trace of a drinking piglet (lactation). The trough after 100 s is due to a short loss of radio communication between the transmitter and the receiver of the EEG recording system. Afterward, there are some muscle or movement artifacts. Muscle artifacts are characterized by very high delta band amplitudes. In contrast, EEG activity is characterized by a gradual decline of amplitude power from slow to fast waves (see, for example, between 200 and 250 s). <a href="https://www.jove.com/files/ftp_upload/58226/58226fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

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 ...

noninvasive-eeg-recordings-from-freely-moving-piglets

Nanyang Technological University

Research

JoVE Journal

Neuroscience

7.2K Views.  Free University Berlin. Hier presenteren we een protocol aan record telemetrische electroencephalograms (hersenfotos) van de vrij bewegende biggen rechtstreeks in het varkenshok zonder het gebruik van een kalmerend middel, waardoor het mogelijk is graag typische EEG patronen tijdens non - REM-slaap, zoals spindel barst.

Video: Noninvasive EEG Recordings from Freely Moving Piglets

Recording EEG in Freely Moving Neonatal Rats Using a Novel Method

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such as epilepsy and neurodegenerative disorders. However, it is technically difficult to obtain EEG recordings in neonates as it requires specialized handling and great care. Here, we present a novel method to record EEG in neonatal rat pups (P8-P15). We designed a simple and reliable electrode using computer pin loci; it can be easily implanted into the skull of a rat pup to record high-quality EEG signals in the normal and epileptic brain. Pups were given an intraperitoneal (i.p.) injection of the neurotoxin kainic acid (KA) to induce epileptic seizures. The surgical implantation performed in this procedure is less expensive than other EEG procedures for neonates. This method allows one to record high-quality and stable EEG signals for more than 1 week. Furthermore, this procedure can also be applied to adult rats and mice to study epilepsy or other neurological disorders.

Here, we introduce a novel technique designed to record electroencephalography (EEG) in freely moving neonatal epileptic pups and describe its procedures, features, and applications. This method allows one to record EEG for more than 1 week.

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such ...

Adaptation of Microelectrode Array Technology for the Study of Anesthesia-induced Neurotoxicity in the Intact Piglet Brain

Every year, millions of children undergo anesthesia for a multitude of procedures. However, studies in both animals and humans have called into question the safety of anesthesia in children, implicating anesthetics as potentially toxic to the brain in development. To date, no studies have successfully elucidated the mechanism(s) by which anesthesia may be neurotoxic. Animal studies allow investigation of such mechanisms, and neonatal piglets represent an excellent model to study these effects due to their striking developmental similarities to the human brain.
This protocol adapts the use of enzyme-based microelectrode array (MEA) technology as a novel way to study the mechanism(s) of anesthesia-induced neurotoxicity (AIN). MEAs enable real-time monitoring of in vivo neurotransmitter activity and offer exceptional temporal and spatial resolution. It is hypothesized that anesthetic neurotoxicity is caused in part by glutamate dysregulation and MEAs offer a method to measure glutamate. The novel implementation of MEA technology in a piglet model presents a unique opportunity for the study of AIN.

This study explores the novel use of enzyme-based microelectrode array (MEA) technology to monitor in vivo neurotransmitter activity in piglets. The hypothesis was that glutamate dysregulation contributes to the mechanism of anesthetic neurotoxicity. Here, we present a protocol to adapt MEA technology to study the mechanism of anesthesia-induced neurotoxicity.

Every year, millions of children undergo anesthesia for a multitude of procedures. However, studies in both animals and humans have called into question ...

Subdural Soft Electrocorticography (ECoG) Array Implantation and Long-Term Cortical Recording in Minipigs

Neurological impairments and diseases can be diagnosed or treated using electrocorticography (ECoG) arrays. In drug-resistant epilepsy, these help delineate the epileptic region to resect. In long-term applications such as brain-computer interfaces, these epicortical electrodes are used to record the movement intention of the brain, to control the robotic limbs of paralyzed patients. However, current stiff electrode grids do not answer the need for high-resolution brain recordings and long-term biointegration. Recently, conformable electrode arrays have been proposed to achieve long-term implant stability with high performance. However, preclinical studies for these new implant technologies are needed to validate their long-term functionality and safety profile for their translation to human patients. In this context, porcine models are routinely employed in developing medical devices due to their large organ sizes and easy animal handling. However, only a few brain applications are described in the literature, mostly due to surgery limitations and integration of the implant system on a living animal.
Here, we report the method for long-term implantation (6 months) and evaluation of soft ECoG arrays in the minipig model. The study first presents the implant system, consisting of a soft microfabricated electrode array integrated with a magnetic resonance imaging (MRI)-compatible polymeric transdermal port that houses instrumentation connectors for electrophysiology recordings. Then, the study describes the surgical procedure, from subdural implantation to animal recovery. We focus on the auditory cortex as an example target area where evoked potentials are induced by acoustic stimulation. We finally describe a data acquisition sequence that includes MRI of the whole brain, implant electrochemical characterization, intraoperative and freely moving electrophysiology, and immunohistochemistry staining of the extracted brains.
This model can be used to investigate the safety and function of novel design of cortical prostheses; mandatory preclinical study to envision translation to human patients.

Subdural Soft Electrocorticography ECoG Array Implantation and Long-Term Cortical Recording in Minipigs

Here, we present a method for the long-term performance and safety assessment of soft subdural electrode arrays in a minipig model, describing surgical method and tools, postoperative magnetic resonance imaging, electrophysiology of the auditory cortex, electrochemical properties of the implant, and postmortem immunochemistry.

Neurological impairments and diseases can be diagnosed or treated using electrocorticography (ECoG) arrays. In drug-resistant epilepsy, these help ...

Bioengineering

Noninvasive Electrocardiography in the Perinatal Mouse

Electrocardiography (ECG) has long been relied upon as an effective and reliable method of assessing cardiovascular (and cardiopulmonary) function in both human and animal models of disease. Individual heart rate, rhythm, and regularity, combined with quantitative parameters collected from ECG, serve to assess the integrity of the cardiac conduction system as well as the integrated physiology of the cardiac cycle. This article provides a comprehensive description of the methods and techniques used to perform a noninvasive ECG on perinatal and neonatal mouse pups as early as the first postnatal day, without requiring the use of anesthetics. This protocol was designed to directly address a need for a standardized and repeatable method for obtaining ECG in newborn mice. From a translational perspective, this protocol proves to be entirely effective for characterization of congenital cardiopulmonary defects generated using transgenic mouse lines, and particularly for analysis of defects causing lethality at or during the first postnatal days. This protocol also aims to directly address a gap in the scientific literature to characterize and provide normative data associated with maturation of the early postnatal cardiac conduction system. This method is not limited to a specific postnatal timepoint, but rather allows for ECG data collection in neonatal mouse pups from birth to postnatal day 10 (P10), a window that is of critical importance for modeling human diseases in vivo, with particular emphasis on congenital heart disease (CHD).

Here, we present a noninvasive electrocardiography (ECG) protocol, optimized for early postnatal mice, that does not require the use of anesthetics.

Electrocardiography (ECG) has long been relied upon as an effective and reliable method of assessing cardiovascular (and cardiopulmonary) function in both ...

Medicine

Echocardiography Recording in Awake Miniature Pigs

Echocardiography uses ultrasonic waves to non-invasively assess cardiac structure and function and is the standard of care for cardiac assessment and monitoring. The miniature pig, or minipig, is increasingly being used as a model of cardiac disease in medical research. Pigs are notoriously difficult to restrain and handle safely, and, therefore, research echocardiography in this species is almost always performed under anesthesia or heavy sedation. Anesthetics and sedatives universally affect cardiovascular function and may cause the depression of cardiac output and blood pressure, increases or decreases in heart rate and systemic vascular resistance, changes in the electrical rhythm, and altered coronary blood flow. Therefore, sedated or anesthetized echocardiography may not accurately depict the progression of cardiac disease in large animal models, thereby limiting the translational value of these important studies. This paper describes a novel device that allows for standing awake echocardiography in minipigs. In addition, training techniques used to teach pigs to tolerate this painless and non-invasive procedure without the need for hemodynamic-altering anesthetics are described. Standing awake echocardiography represents a safe and feasible way to perform the most common cardiac monitoring test in minipigs for cardiovascular research.

A simple cart construct, built to perform research echocardiography in standing awake minipigs, is described, along with building considerations, training techniques, and representative ultrasound images.

Echocardiography uses ultrasonic waves to non-invasively assess cardiac structure and function and is the standard of care for cardiac assessment and ...

Continuous EEG/ECG Recordings in Rabbits Using Subdermal Electrode Placement

Surgical Implant Procedure and Wiring Configuration for Continuous Long-Term EEG/ECG Monitoring in Rabbits

A multi-system approach that includes the continuous collection of electroencephalogram (EEG) and electrocardiogram (ECG) recordings facilitates a comprehensive assessment of electrical activity in the brain and heart, particularly leading up to and surrounding episodic events. Building on our previous protocol that facilitates the collection of intermittent EEG/ECG recordings from conscious restrained rabbits, we developed a protocol for the collection of continuous EEG/ECG recordings from unrestrained rabbits. This new method enables high-quality 24/7 recordings in the housing cage, which captures the normal range of physiological states and enables the rabbits to move, eat, drink, and sleep freely. It enables comprehensive assessments of the prevalence, incidence, and susceptibility to EEG/ECG abnormalities, seizures, arrhythmias, and sudden death. This procedure involves the surgical placement of subdermal electrodes and the design and manufacturing of a robust wiring system that is impervious to damage by the rabbits. The surgical procedure includes two incisions and the sub-dermal tunneling of nine electrodes and wires that exit through a custom-made port. The external connector attaches to a wire harness that includes an electrical swivel, which allows for&#160;free range of rabbit motion throughout its cage. Additionally, the wires are enclosed in a metal sheath suspended by a retractor cable from the ceiling of the rabbit&#39;s cage. The wires are then connected to an amplifier/digitizer for the acquisition of high-quality continuous EEG/ECG recordings.

The study outlines a protocol for the design, manufacturing, and placement of a novel continuous EEG/ECG recording system in rabbits. This hard-wired system allows for continuous EEG/ECG recordings from nine distinct electrodes on the head and chest, which facilitates comprehensive assessments of electrical activity in the brain and heart.

A multi-system approach that includes the continuous collection of electroencephalogram (EEG) and electrocardiogram (ECG) recordings facilitates a ...

Measuring Brain Glutamate Levels Under Anesthesia in Neonatal Piglets Using a Microelectrode Array

Source: Geyer, E. D., et al. <a href="https://app.jove.com/v/57391">Adaptation of Microelectrode Array Technology for the Study of Anesthesia-induced Neurotoxicity in the Intact Piglet Brain.</a> J. Vis. Exp. (2018).
This video demonstrates the measurement of glutamate levels in the brain of an anesthetized neonatal piglet using a microelectrode array (MEA). The procedure involves creating a craniotomy window in the pig skull and inserting the MEA into the brain region of interest. The glutamate-oxidase-coated recording sites of the MEA convert extracellular brain glutamate to hydrogen peroxide, which generates a measurable current. This current is measured and normalized against background noise to determine brain glutamate levels under anesthesia.

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
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JoVE Encyclopedia of Experiments

Neurophysiology

Electrophysiology Techniques

Subdural Implantation of a Soft Electrocorticography Array for Cortical Electrophysiology Recording in Minipigs

Source: Fallegger, F. et al., <a href="https://app.jove.com/v/64997">Subdural Soft Electrocorticography (ECoG) Array Implantation and Long-Term Cortical Recording in Minipigs.</a>&#160;J. Vis. Exp. (2023).
This video demonstrates the implantation of a soft electrocorticography array and the long-term cortical recordings in a minipig. It outlines the steps involved in surgically implanting the array over the minipig&#39;s auditory cortex and recording both baseline and sound stimulus-evoked neuronal action potentials.

Long-Term Continuous Electroencephalography Monitoring in a Rodent Pup

Source: Zayachkivsky, A. et al. <a href="https://app.jove.com/v/52554">Long-term Continuous EEG Monitoring in Small Rodent Models of Human Disease Using the Epoch Wireless Transmitter System.</a> J. Vis. Exp. (2015)
The video demonstrates long-term continuous electroencephalography (EEG) monitoring in rodent pups using a wireless transmitter system. The transmitter contains two recording electrodes and one reference electrode extending to the brain&#39;s surface. Upon placing the pup in a recording chamber, EEG can be continuously monitored throughout the pup&#39;s development into adulthood.

Recording of Induced Seizures through Electroencephalography in Freely Moving Rat Pups

Source: Huo, Q. et al. <a href="https://app.jove.com/v/55489">Recording EEG in Freely Moving Neonatal Rats Using a Novel Method.</a> J. Vis. Exp. (2017)
The video demonstrates the recording of electroencephalogram (EEG) signals from seizure-induced rat pups. Take a freely moving pup implanted with electrodes connected to a data acquisition system. A neurotoxin is administered to induce epileptic seizures, and the resulting electrical bursting activity is monitored using the EEG signal.

Noninvasive EEG Recordings from Freely Moving Piglets

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