Name: A Cost-Effective and Minimally Invasive Protocol for Chronic Multi-Site Electroencephalography Recording in Freely Moving Mice (Video) | JoVE Journal
Uploaded: 2025-10-10T14:30:00.000+00:00
Duration: 7 min 47 s
Description: Learn a cost-effective, minimally-invasive protocol for chronic multi-site EEG recording in freely moving mice. This method enables stable long-term neural monitoring for preclinical neuroscience research.

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5 minutes

DTB is supported by NEI grant R01EY036089, and NIA grant RF1AG060754. XF was supported by grants from the James Fickel Alzheimer&#39;s Disease Research Fund, EY028158, and EY032488.

This protocol received approval from the Augusta University Animal Care and Use Committee. The National Institutes of Health Guide for Care and Use of Laboratory Animals was followed at each step of the experiment. All possible measures were implemented to minimize the number of animals utilized in this study. The mice used for this study are 2-month-old wild-type C57Bl6J. The time required to perform each step is included in the respective steps.
1. Preparing plug pins with electrodes (5 min)
<ol>
	<li>Use USB type B female plug pins with 5 pins to solder with 0.003&#34; platinum-iridium wire. Remove the coat from the wire before soldering it with the pin. The fourth pin out of the five pins is the ground pin; do not use it to connect to the electrodes (Figure 1A). Use the other 4 pins to connect the electrodes.</li>
	<li>Bend the pins by about 45&#176; and wrap the wires around each pin twice to make sure the wires remain connected properly and do not come off (Figure 1A).</li>
	<li>Add a bit of solder rosin flux paste to each pin to clean the surface of the pin so it can be soldered effectively.</li>
	<li>Add a small piece of solder wire to each pin, use a soldering iron to melt the solder wire, and permanently attach the pin to the platinum-iridium wire (Figure 1B-D). 
	NOTE: Use a 45&#176; forceps to hold the wire, and use another one to wrap around the pin. Do the whole procedure under a bright-field microscope. Cut the remaining wire after wrapping and soldering, and keep the other end attached to the electrodes. Sterilize the connector with platinum-rhodium wire and the electrodes before the surgery.</li>
</ol>
2. Implanting electrodes (30 min)
<ol>
	<li>Anesthetize the mouse in an anesthesia chamber and mount the mouse on the stereotaxic stage. Make sure that the mouse is not under-dosed before mounting it into the stage by pinching the hind leg and waiting till it stops responding to the pinch. Quickly start the isoflurane/oxygen vaporizer on the nose at a rate of 1.5% v/v.</li>
	<li>Inject the mouse with carprofen (5 mg/kg) to reduce inflammatory responses and pain, and dexamethasone (0.1 mg/kg IM) to reduce inflammation and brain swelling. Use eye ointment to keep the eyes moist, as long exposure to anesthetics might dry the eyes and damage them.</li>
	<li>Use a hair remover or shave the top of the skull to expose the skin. Follow aseptic technique to clean the area of incision using 70% ethanol and iodine pads.</li>
	<li>Make a clear single stroke incision in the middle of the head with a scalpel. Cut around the incision to expose the site of electrode implantation. Make sure muscles are not exposed (Figure 2A).</li>
	<li>Wash with 0.9% NaCl solution and dry the surface. Scrub the surface with cotton swabs soaked or dipped in hydrogen peroxide. Connective tissue on the bone that is persistent may be removed with a scalpel. Wait at least 1 min after scrubbing.</li>
	<li>Wash with 0.9% NaCl solution and dry the surface before starting to drill.</li>
	<li>Use a dental drill to make the surface of the skull rough to promote acrylic adhesion.</li>
	<li>Measure and point the locations of the electrode implantation (AP: +2, -4, ML: &#177;1.5)20 (Figure 2B).</li>
	<li>Drill the surface using 1.4 mm drills and put 4 bone screws (1.5 mm) in the hole using precision screwdrivers. Make sure the drilling does not make holes through the bone. The screws should not make a hole in the brain, but rather touch the surface (Figure 2C).</li>
	<li>Wash with a 0.9% NaCl solution if there is any blood and wait for it to dry up. Use a vacuum if necessary.</li>
	<li>Wrap the wires attached to the USB connector around each of the screws 2-4 times and cut the leftover wires (Figure 2D).</li>
	<li>Put a small drop of super glue (Loctite) on the top of each screw and allow it to dry to make the connection strong. Make sure the connector is placed in the middle of the skull and not touching the skull or any of the electrodes (Figure 2E).</li>
	<li>Use cyanoacrylate to slowly build the headcap a little bit at a time. Avoid applying a layer that is too thick, as it can heat the bone. Attach a big screw on the flat surface of the connector, which does not contact the bone or animal, using dental cement to aid USB cable plugging in (Figure 2F).</li>
	<li>Let the head cap dry for at least 2 min before unhooking the mouse from the stereotaxic stage. Observe the mouse for the next 24 h on a heat pad.</li>
	<li>Treat the mouse with carprofen for the next 7 days at a dosage of 5 mg/kg every 12 h. The mouse will be ready for EEG recording after 2 weeks of waiting to promote bone growth at the acrylic interface. 
	NOTE: Try to keep the connector as close to the skull as possible. Make sure it does not touch the skull or the bone screws. Make sure the wires are not connected to each other at either end. Be careful about Cyanoacrylate getting into the USB connector and eyes.</li>
</ol>
3. Recording EEG (65 min)
<ol>
	<li>Record EEG of each mouse for 1 h, 30 min before Pentylenetetrazol (PTZ) treatment and 30 min after 20 mg/Kg PTZ treatment.</li>
	<li>Plug the USB cable into the connector. Connect the USB cable to a differential alternating current (AC) amplifier using alligator clips with the Gain set to 10k and filtered between 0.1 Hz and 250 Hz21. Sample EEG signal at 1000 Hz (Figure 3).</li>
	<li>Record the outputs from the amplifier simultaneously on the computer and display them on an oscilloscope for real-time monitoring. Connect the amplifier outputs to a data acquisition and signal conditioning (e.g., NIDAQ) USB device attached to the computer (Figure 3).</li>
	<li>Use the Python code to record the EEG signal (available at&#160;https://github.com/schrodi159/blakelabeeg). The code digitally filters the signal at 0.1 Hz and 250 Hz. 
	NOTE: Recording EEG in a room without electrical interference improves the quality of the data and recording.</li>
</ol>
4. Data interpretation
<ol>
	<li>Use the Python code to visualize data (available at https://github.com/schrodi159/blakelabeeg). Identify interictal discharges from each recording (Figure 4A). 
	NOTE: Interictal discharge was considered if the waveform is twice the baseline and has a duration less than 200 ms22 and follows at least 4 out of the following 5 criteria- di- or triphasic wave with a pointed peak, different duration than background, asymmetry of wave form, background activity is disrupted by the presence, and followed by an after going slow wave8,20,22.</li>
</ol>

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<li>Colgin, L. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Oscillations+and+hippocampal-prefrontal+synchrony%5BTitle%5D)+AND+%22Curr+Opin+Neurobiol%22%5BJournal%5D)">Oscillations and hippocampal-prefrontal synchrony.</a> Curr Opin Neurobiol. 21 (3), 467-474 (2011).</li>
<li>Amat-Foraster, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Temporally+dissociable+effects+of+ketamine+on+neuronal+discharge+and+gamma+oscillations+in+rat+thalamo-cortical+networks%5BTitle%5D)+AND+%22Neuropharmacology%22%5BJournal%5D)">Temporally dissociable effects of ketamine on neuronal discharge and gamma oscillations in rat thalamo-cortical networks.</a> Neuropharmacology. 137, 13-23 (2018).</li>
<li>Sun, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Closed-loop+stimulation+using+a+multiregion+brain-machine+interface+has+analgesic+effects+in+rodents%5BTitle%5D)+AND+%22Sci+Transl+Med%22%5BJournal%5D)">Closed-loop stimulation using a multiregion brain-machine interface has analgesic effects in rodents.</a> Sci Transl Med. 14 (651), eabm5868(2022).</li>
<li>Kang, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Closed-loop+direct+control+of+seizure+focus+in+a+rodent+model+of+temporal+lobe+epilepsy+via+localized+electric+fields+applied+sequentially%5BTitle%5D)+AND+%22Nat+Commun%22%5BJournal%5D)">Closed-loop direct control of seizure focus in a rodent model of temporal lobe epilepsy via localized electric fields applied sequentially.</a> Nat Commun. 13 (1), 7805(2022).</li>
<li>Armstrong, C., Krook-Magnuson, E., Oijala, M., Soltesz, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Closed-loop+optogenetic+intervention+in+mice%5BTitle%5D)+AND+%22Nat+Protoc%22%5BJournal%5D)">Closed-loop optogenetic intervention in mice.</a> Nat Protoc. 8 (8), 1475-1493 (2013).</li>
<li>Maheshwari, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Rodent+EEG%3A+Expanding+the+spectrum+of+analysis%5BTitle%5D)+AND+%22Epilepsy+Curr%22%5BJournal%5D)">Rodent EEG: Expanding the spectrum of analysis.</a> Epilepsy Curr. 20 (3), 149-153 (2020).</li>
<li>Ahuis, T. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Evaluation+of+variation+in+preclinical+electroencephalographic+spectral+power+across+multiple+laboratories+and+experiments%3A+An+EQIPD+study%5BTitle%5D)+AND+%22PLoS+One%22%5BJournal%5D)">Evaluation of variation in preclinical electroencephalographic spectral power across multiple laboratories and experiments: An EQIPD study.</a> PLoS One. 19 (10), e0309521(2024).</li>
<li>Papazoglou, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Non-restraining+EEG+radiotelemetry%3A+Epidural+and+deep+intracerebral+stereotaxic+EEG+electrode+placement%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Non-restraining EEG radiotelemetry: Epidural and deep intracerebral stereotaxic EEG electrode placement.</a> J Vis Exp. (112), e54216(2016).</li>
<li>Kadam, S. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Methodological+standards+and+interpretation+of+video-electroencephalography+in+adult+control+rodents%3A+A+TASK1-WG1+report+of+the+AES%2FILAE+Translational+Task+Force+of+the+ILAE%5BTitle%5D)+AND+%22Epilepsia%22%5BJournal%5D)">Methodological standards and interpretation of video-electroencephalography in adult control rodents: A TASK1-WG1 report of the AES/ILAE Translational Task Force of the ILAE.</a> Epilepsia. 58 (Suppl 4), 10-27 (2017).</li>
<li>Zayachkivsky, A., Lehmkuhle, M. J., Dudek, F. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Long-term+continuous+EEG+monitoring+in+small+rodent+models+of+human+disease+using+the+Epoch+wireless+transmitter+system%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Long-term continuous EEG monitoring in small rodent models of human disease using the Epoch wireless transmitter system.</a> J Vis Exp. (101), e52554(2015).</li>
<li>Kent, B. A., Strittmatter, S. M., Nygaard, H. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sleep+and+EEG+power+spectral+analysis+in+three+transgenic+mouse+models+of+Alzheimer%27s+disease+APP%2FPS1%2C+3xTgAD%2C+and+Tg2576%5BTitle%5D)+AND+%22J+Alzheimers+Dis%22%5BJournal%5D)">Sleep and EEG power spectral analysis in three transgenic mouse models of Alzheimer's disease APP/PS1, 3xTgAD, and Tg2576.</a> J Alzheimers Dis. 64 (4), 1325-1336 (2018).</li>
<li>Luttjohann, A., Schoffelen, J. M., van Luijtelaar, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Peri-ictal+network+dynamics+of+spike-wave+discharges%3A+Phase+and+spectral+characteristics%5BTitle%5D)+AND+%22Exp+Neurol%22%5BJournal%5D)">Peri-ictal network dynamics of spike-wave discharges: Phase and spectral characteristics.</a> Exp Neurol. 239, 235-247 (2013).</li>
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</ol>

DTB is a paid consultant of the Alfred Mann Foundation. The authors have no competing financial interests or other conflicts of interest pursuant to this work.

In this study, we developed and validated a robust, cost-effective, and minimally invasive protocol for chronic, multi-site EEG recording in freely moving mice. The successful implantation of screw electrodes and custom-fabricated platinum-iridium electrodes soldered to a USB connector, along with the observed survival rate and recording quality, demonstrates the feasibility and reliability of the technique in chronic recordings. Notably, this protocol allows for precise electrophysiological data collection without exten...

Electroencephalography (EEG) provides a direct measure of brain electrical activity and is widely used in diagnosing epilepsy1. In recent years, EEG techniques have been increasingly adapted for use in small animal models to study neurological disorders, sleep physiology, and brain network dynamics2,3,4. With the advent of genetically modified mouse models and significant advancements in recording technologies, rodent EEG has become an essential tool for preclinical research, offering valuable insights into translational mechanisms relevant to human brain health5,6.
Capturing and manipulating neural activity simultaneously is critical for studying brain dynamics at both macro- and micro-circuit levels. This dual approach enables real-time monitoring of the neural networks involved in seizure initiation and progression. Epilepsy, characterized by recurrent and often unpredictable seizures, arises from disruptions in complex brain circuits4. Despite extensive research, the mechanisms governing seizure spread and onset remain incompletely understood, in part due to limited use of technologies that allow for simultaneous recordings across multiple brain areas7.
EEG recording from animal models that recapitulate human neurological disorders has revealed interictal spikes, spike-and-wave discharges, and seizure onset patterns that closely mirror those seen in human patients8,9, thereby advancing our understanding of electrophysiological changes taking place in the human brain. Similarly, EEG abnormalities detected in models of Alzheimer&#39;s disease, autism spectrum disorder, and schizophrenia provide critical insights into disrupted neural oscillatory activity and highlight potential therapeutic targets10.
Despite differences in brain anatomy and scale, mouse and human EEGs exhibit striking similarities2,11. Both exhibit characteristic oscillatory frequency bands -- delta, theta, alpha, beta, and gamma -- with power spectra generally following a 1/f distribution2,11. Transitions between brain states, such as the emergence of delta activity during non-rapid eye movement (NREM) sleep or increased gamma synchronization during attention and memory tasks, are conserved across species. Moreover, epileptiform activity, including high-frequency oscillations (HFOs) and ictal patterns, show comparable temporal and spectral profiles in both mice and humans7.
The conserved features of rodent and human EEG make mouse models highly translational for studying brain disorders. Mouse EEG allows invasive, high-resolution recordings enabling detailed circuit-level analysis12. It also supports testing of neuromodulatory strategies, including pharmacological agents, optogenetic control, and closed-loop stimulation13,14, which can be coupled with behavioral and molecular tools to precisely interrogate neural dysfunction.
Nevertheless, caution must be taken when extrapolating findings. The smaller size and simpler cortical structure of the mouse brain can affect signal propagation, and cognitive event-related potentials (ERPs) may be less prominent compared to humans15. Ensuring consistency in electrode placement, signal referencing, and analytical pipelines is critical to improving reproducibility and cross-laboratory validity16.
Recording EEG in small animals presents both opportunities and challenges. Mouse EEG is typically acquired using chronically implanted electrodes positioned either epidurally on the skull surface or as depth electrodes inserted into subcortical structures17,18. Surface electrodes, such as screw or wire electrodes placed on the dura mater, are minimally invasive and suitable for long-term, longitudinal recordings. Such electrodes are below the bone, which provides a high impedance barrier to recording. Accordingly, dural electrodes in rodents can be thought of as more comparable to electrocorticography (eCoG) than to EEG. Depth electrodes, in contrast, offer higher spatial resolution and enable access to deep brain regions such as the hippocampus, thalamus, or amygdala, facilitating studies on seizure networks and oscillatory coupling across regions distribution2,11.
Modern EEG systems for rodents support multi-channel recording with high temporal resolution and are often coupled with video monitoring for behavioral correlation18. Additionally, wireless EEG systems allow for untethered, real-time acquisition in freely behaving animals, minimizing movement constraints and stress19. Though with time these modernizations were made commercially available, they are either very expensive or are too invasive to study the rodent model over a long period of time.
To address this gap, we present a versatile and cost-effective protocol for multi-site EEG acquisition in rodent models, suitable for long-term studies with minimal invasiveness. This EEG recording approach is particularly suitable for studies requiring high-resolution assessment of cortical activity in mice under controlled experimental conditions. It is best applied when (i) the animal can tolerate brief anesthesia during electrode implantation and fully recover, (ii) stable head positioning or minimal movement is ensured during recordings, (iii) long-term or repeated monitoring of neural activity is desired, and (iv) the experimental design can accommodate single- or limited multi-animal recording depending on amplifier capacity. Investigators should consider these constraints to determine whether this method aligns with their experimental objectives.

<table><tbody><tr><td>0.003&quot; platinum iridium wire</td><td>AM systems</td><td>777000</td><td></td></tr><tr><td>1.5 mm Bone screws</td><td>Antrin Miniature specialities</td><td></td><td>000-120X1/16 SL BIND MS SST</td></tr><tr><td>AC amplifier&amp;nbsp;</td><td>AM Systems</td><td></td><td></td></tr><tr><td>Carprofen</td><td>Covetrus</td><td>11695-6935-1</td><td></td></tr><tr><td>Coldpac Denture acrylic base</td><td>Yates Motloid Company</td><td>https://www.yates-motloid.com/collections/coldpac/denture-base</td><td></td></tr><tr><td>Dental drill 1.4 mm</td><td>Volvere GX</td><td>N/A</td><td></td></tr><tr><td>Dexamethasone</td><td>VEDCO</td><td>50989-437-12</td><td></td></tr><tr><td>Eye lube</td><td>Optix Care</td><td>https://theoptixcare.com/</td><td></td></tr><tr><td>Hydrogen peroxide</td><td>Sigma Aldrich</td><td>7722-84-1</td><td></td></tr><tr><td>NIDAQ USB&amp;nbsp;</td><td>National Instruments</td><td>https://www.ni.com/en/shop/data-acquisition/entry-level-usb-daq.html</td><td>Data acquisition and signal conditioning USB&amp;nbsp;</td></tr><tr><td>Pentylenetetrazol</td><td>Caymen Chemicals</td><td>18682</td><td></td></tr><tr><td>Solder rosin flux paste&amp;nbsp;</td><td>Weller</td><td>https://www.weller-tools.com/us/en/consumer/products/soldering-accessories/</td><td></td></tr><tr><td>Solder wire 0.32&quot;</td><td>Radio Shack</td><td>N/A</td><td></td></tr><tr><td>Super glue</td><td>Loctite</td><td>N/A</td><td></td></tr><tr><td>USB type B female plugs</td><td>QM Seller</td><td>X00292ABU9</td><td></td></tr></tbody></table>

a cost-effective and minimally invasive protocol for chronic multi-site electroencephalography recording in freely moving mice

A Cost-Effective and Minimally Invasive Protocol for Chronic Multi-Site Electroencephalography Recording in Freely Moving Mice

Electroencephalography (EEG) serves as a fundamental tool for tracking electrical activity in the brain and has become increasingly important in both clinical diagnostics and preclinical animal research. While rodent EEG offers a powerful platform for modeling human neurological disorders, long-term recordings are often limited by the high cost, invasiveness, or technical complexity of existing systems. Here, we present a reliable, accessible, economically viable, and minimally intrusive protocol for chronic, multi-site cortical EEG acquisition in freely moving mice. The technique involves fabricating platinum-iridium wires with screw electrodes connected to a universal serial bus (USB)-type interface, which are anchored epidurally using bone screws and secured with adhesive and dental cement. The system allows for stable signal capture over several months, as demonstrated in wild-type C57BL/6J mice with an 85% post-operative survival rate (n = 20). EEG was sampled at 1,000 Hz and filtered between 1 Hz and 500 Hz using a differential amplifier setup. To validate the system, pentylenetetrazol (20 mg/kg) was administered to induce seizure-like activity, leading to a marked increase in interictal discharges-from 2-5 at baseline to 20-51 events post-injection-accompanied by increased signal amplitude. Discharges were identified based on waveform morphology and signal characteristics matching recognized electrophysiological criteria. The setup is compatible with behavioral video tracking and open-source analysis pipelines, and supports integration with pharmacological, genetic, or neuromodulation studies. This method provides a stable and adaptable platform for investigating brain network dynamics in rodent models, with applications in epilepsy research and beyond.

Electrodes were implanted in 20 mice on a C57Bl6J background, including 5 wild-type C57Bl6J mice, with a post-operative survival rate of 85% maintained up to 6 months after the surgery (Figure 4B). After 6 months, the headcaps began to detach, and all mice were euthanized at 8 months of age. The average weight of the headcaps assembly, including the connector and screws, was 1.13 g (n = 20). The mice regained consciousness within 30 min post-surgery and resumed normal movement and gazing wit...

This protocol was developed to create a reliable and easily accessible system for recording freely moving rodent EEG.

Electroencephalography (EEG) serves as a fundamental tool for tracking electrical activity in the brain and has become increasingly important in both ...

This protocol enables cost-efficient, minimally-invasive, high-quality mouse EEG recordings, making long-term neural monitoring accessible for preclinical research. The major challenges of chronic EEG recording are implant instability and head cap longevity, signal degradation, massive data analysis, and inaccessibility of expensive commercialized systems. To begin, use a USB type B female plug with five pins and solder it with a 0.003-inch platinum iridium wire.Do not use the fourth pin, as it is the ground pin, and instead use the other four pins to connect the electrodes. Bend the pins by approximately 45 degrees and wrap the wires around each pin twice to ensure a strong connection that will not come off. Now, apply a small amount of solder resin flux paste to each pin to clean the surface for effective soldering.Then, place a small piece of solder wire on each pin. Using a soldering iron, melt the solder wire to permanently attach the platinum iridium wire to the pins. After confirming deep anesthesia, start the isoflurane oxygen ventilator on the nose at a rate of 1.5%volume per volume.Now, inject the mouse with carprofen at five milligrams per kilogram to reduce inflammation and pain. Inject dexamethasone at 0.1 milligrams per kilogram intramuscularly to reduce inflammation and brain swelling. Apply eye ointment to prevent the eyes from drying during anesthesia.After removing the fur, clean the incision side on the skull with 70%ethanol, followed by iodine pads while following a septic technique. Next, use a scalpel to make a single clear incision in the middle of the head. Cut around the incision to expose the site of electrode implantation, ensuring that the muscles are not exposed.Wash the skull surface with 0.9%sodium chloride solution. Dry the surface and scrub the skull with cotton swabs dipped in hydrogen peroxide. Use a scalpel to remove any remaining connective tissue on the bone.After one minute, wash the surface again with 0.9%sodium chloride solution and dry it before drilling. Use a dental drill to roughen the skull surface to promote acrylic adhesion. Measure and mark the electrode implantation sites at anterior/posterior positions, plus two and minus four, and medial lateral positions, plus or minus 1.5.Drill the surface of the skull with 1.4-millimeter drills and insert four bone screws of 1.5 millimeters into the drilled sites using precision screwdrivers. Ensure the screws touch only the surface and do not enter the brain. Wrap the wires from the USB connector around each screw two to four times and cut off any excess wire.Apply a small drop of super glue on the top of each screw and let it dry to strengthen the connection. Ensure that the connector is positioned in the middle of the skull without touching the skull or electrodes. Then, slowly build the head cap using cyanoacrylate, applying thin layers to prevent overheating of the bone.Using dental cement, attach a large screw to the flat surface of the connector to facilitate USB cable plugging. Allow the head cap to dry for at least two minutes before removing the mouse from the stereotaxic stage. Place the mouse on a heating pad and observe it for 24 hours.Treat the mouse with carprofen at five milligrams per kilogram every 12 hours for seven days. Wait for two weeks to let the bone grow at the acrylic interface before proceeding with electroencephalography or EEG recording. Record the EEG signal of each mouse for one hour, including 30 minutes before pentylenetetrazole treatment and 30 minutes after administering 20 milligrams per kilogram pentylenetetrazole.Plug the USB cable into the mouse's connector. Attach the USB cable to a differential alternating current amplifier using alligator clips. Set the gain to 10, 000 and filter between 0.1 and 250 hertz.Sample the electroencephalography signal at 1, 000 hertz. Record the amplifier outputs simultaneously on the computer and display the signals in real time on the oscilloscope. Connect the amplifier outputs to a data acquisition and signal conditioning USB device attached to the computer.Finally, record the EEG signal using the Python code and filter it between 0.1 hertz and 250 hertz and visualize the data. Electrodes were implanted in 20 C57BL/6J background mice, including five wild-type mice with a postoperative survival rate of 85%maintained up to six months after surgery. EEG recordings captured pentylenetetrazole-induced electrophysiological changes, as shown by an increased number of interictal discharges in the mice following pentylenetetrazole injection.The amplitude of interictal discharges after pentylenetetrazole injection was visibly higher across three different electrodes as shown in representative EEG traces. Our study established a simple stable EEG system in freely-moving mice, showing reliable long-term recordings at the clear serial-related discharges. This protocol advances neuroscience by providing accessible long-term EEG recordings in freely-moving rodents, supporting broader studies of brain disorders and therapies.Future research will focus on refining electrode design, expanding multi-region recordings, and integrating EEG with behavioral, pharmacological, and genetic manipulations.

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Research

JoVE Journal

Neuroscience

In this article, we described the surgery procedure and handling tips for implantation of ultra-thin polyimide-based microelectrode array (PBM-array) on the mouse skull for acquisition of high-density encephalography (EEG) in a mouse model.

High-density EEG Recordings of the Freely Moving Mice using Polyimide-based Microelectrode

The recording of electroencephalogram (EEG) and electromyogram (EMG) in freely behaving mice is a critical step to correlate behavior and physiology with sleep and wakefulness. The experimental protocol described herein provides a cable-based system for acquiring EEG and EMG recordings in mice.

Polygraphic Recording Procedure for Measuring Sleep in Mice

Instructions for the low-cost construction and surgical implantation of a chronic transcranial high-density electroencephalographic montage into mice are provided. Signal recording, extraction, and processing techniques are also described.

High-density Electroencephalographic Acquisition in a Rodent Model Using Low-cost and Open-source Resources

We designed a dry-type 16 channel EEG sensor which is non-invasive, deformable, and re-usable. This paper describes the whole process from manufacturing the proposed EEG electrode to signal processing of visual evoked potential (VEP) signals measured on a mouse scalp using a dry non-invasive multi-channel EEG sensor.

Visual Evoked Potential Recordings in Mice Using a Dry Non-invasive Multi-channel Scalp EEG Sensor

Here, we present a protocol to record brain and heart bio signals in mice using simultaneous video, electroencephalography (EEG), and electrocardiography (ECG). We also describe methods to analyze the resulting EEG-ECG recordings for seizures, EEG spectral power, cardiac function, and heart rate variability.

Simultaneous Video-EEG-ECG Monitoring to Identify Neurocardiac Dysfunction in Mouse Models of Epilepsy

This protocol provides an open source, compiled MATLAB program that generates multitaper spectrograms for electroencephalographic data.

Computer-based Multitaper Spectrogram Program for Electroencephalographic Data

We present an ECG protocol that is technically easy, inexpensive, fast, and affordable in small mice, and can be performed with enhanced sensitivity. We suggest this method as a screening approach for studying pharmacological agents, genetic modifications, and disease models in mice.

Electrocardiogram Recordings in Anesthetized Mice using Lead II

The protocol describes the methodology of extracellular recording in the motor cortex (MC) to reveal extracellular electrophysiological properties in freely moving conscious mice, as well as the data analysis of local field potentials (LFPs) and spikes, which is useful for evaluating the network neural activity underlying behaviors of interest.

Multichannel Extracellular Recording in Freely Moving Mice

A low-cost electroencephalographic recording system combined with a millimeter-sized coil is proposed to drive transcranial magnetic stimulation of the mouse brain in vivo. Using conventional screw electrodes with a custom-made, flexible, multielectrode array substrate, multi-site recording can be carried out from the mouse brain in response to transcranial magnetic stimulation.

Low-Cost Electroencephalographic Recording System Combined with a Millimeter-Sized Coil to Transcranially Stimulate the Mouse Brain In Vivo

This protocol describes a two-phase surgical method to create a large, resealable, dura-sparing cranial window in mice. This technique enables chronic, multi-modal electrophysiological recordings from distributed, deep-brain networks, such as the Default Mode Network, over several weeks.

Surgical Protocol for a Large, Resealable Cranial Window Enabling Longitudinal, Multi-Modal Electrophysiology Recordings of Mouse Default Mode Network

Learn a cost-effective, minimally-invasive protocol for chronic multi-site EEG recording in freely moving mice. This method enables stable long-term neural monitoring for preclinical neuroscience research.

A Cost-Effective and Minimally Invasive Protocol for Chronic Multi-Site Electroencephalography Recording in Freely Moving Mice

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