Noninvasive EEG Recordings from Freely Moving Piglets

Summary

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.

Abstract

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—they drink and sleep in the same cycle as their siblings. Their sleep phases are used for the EEG recordings.

Introduction

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....

Protocol

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's regulations.

1. Setup

1. 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 espec....

Results

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.......

Discussion

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.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Disposable adhesive surface silver/silver chloride electrodes	Spes Medica S.r.l., Genova, Italy		Self adhesive hydrogel electrode
Abralyt HiCl	Easycap GmbH		Abrasive cream
Body Double fast	Smooth On Inc.		Skin adhesive silicone
Telemetry system			Internal development
Picolog 1216	Pico Technology		AD converter
Laptop	Panasonic		Rugged laptop
Receiver			Internal development