implantation of electrodes into a mouse cortex for electrocorticographic recordings

Implantation of Electrodes into a Mouse Cortex for Electrocorticographic Recordings

For electrode implantation, use straight Kelly forceps to slowly screw one electrocorticographic electrode with a straight gold wire, into the vertical axis of the hole in which the AAV was injected, leaving at least 2.5 millimeters of screw outside of the skull to minimize the damage to the dura and the cerebral cortex.
Use a pen to mark the position of the reference electrode 2.6 millimeters lateral right to the midline and 0.7 millimeters posterior to bregma, and the position of the posterior electrocorticographic electrode at 1.5 millimeters lateral right to the midline and 1.5 millimeters anterior to lambda, and the positions of three maintenance screws on the left hemisphere with no specific coordinates, but as distant as possible from each other and from the electrocorticographic electrodes.
Use the drill to carefully pierce the skull perpendicular to the skull surface at the marked positions of the other electrodes and screws, and wash the pierced skull with a 10% povidone-iodine solution.
Block the holes with small rolled pieces of delicate task wipe before installing the screws to prevent bleeding and contamination, and use straight Kelly forceps to insert the screws into the drill holes at the same angle that the holes were pierced. Place a few small drops of dental cement into the center of the ring-like space inside the screws. After covering the eyes of the animal, apply light for three to five minutes to solidify the cement, and use additional dental cement to cover the base of the electrocorticographic electrodes, and the anchor screws to form a crown-shaped contour.
After applying three to five more minutes of light, fill the center of the montage with acrylic cement, and remove the surgical clamps.
Use a synthetic absorbable monofilament suture to close the skin at the front and back of the montage so that the skull is not exposed, and use curved forceps to hold the connector above the montage to carefully align the gold wires of the electrodes with the connector pins. Then, quickly solder each electrode extremity to a single corresponding connector pin.
After removing the mouse from the frame, cover the empty space between the connector and the head with the acrylic cement, and after weighing, place the mouse in a clean cage with a non-meshed lid on a heat pad.

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1. ECoG/EMG electrode implantation
<ol>
	<li>Using straight Kelly forceps, slowly screw one ECoG electrode (with straight gold wire) in the vertical axis in the hole where the AAV was injected. Leave at least 2.5 mm of the screw out of the skull to minimize damage to the dura and cerebral cortex (i.e., for an approximate depth of 1.1 mm from the skull surface; Figure 1D).</li>
	<li>Mark the position of the posterior ECoG electrode and the reference electrode on the skull with a pen at these coordinates: posterior electrode (visual cortex) 1.5 mm lateral right to midline and 1.5 mm anterior to lambda, reference electrode (somatosensory cortex) 2.6 mm lateral right to midline and 0.7 mm posterior to bregma. Also, mark the position of three maintenance screws (acting as anchors between the skull and dental cement to solidify head montage) on the left hemisphere with no specific coordinates, but as distant as possible from each other and from the ECoG electrodes.</li>
	<li>Carefully pierce the skull at the marked position of the other electrodes and anchor screws with the 0.7 mm drill bit. Pierce in a direction perpendicular to the skull surface for each screw (i.e., vertical axis for the posterior electrode but with an angle from the vertical axis for other sites). Wash the pierced skull with a 10% povidone-iodine solution, and block the holes with small, rolled pieces of delicate task wipers before installing the screws to prevent bleeding and contamination.</li>
	<li>Using the straight Kelly forceps, screw the maintenance screws in the left hemisphere and then screw the last two electrodes in the right hemisphere. Make sure to screw with the same angle that the holes were pierced and to leave at least 2.5 mm of each screw out of the skull (Figure 1D). 
	NOTE: To maximize the solidity of the final montage and the quality of the electrophysiological signals, be careful not to touch any screws when installing the next one.</li>
	<li>Place a few small drops of dental cement in the center of the ring-like space inside the screws.</li>
	<li>Cover the eyes of the mice, and apply light for 3-5 min to help cement solidification. Once the EMG electrodes are holding firmly, cover the base of the ECoG electrodes and the base of the anchor screws with dental cement to form a crown-shaped contour. Cover the eyes of the mice, and apply light for 3-5 min to help cement solidification. 
	NOTE: Do not apply cement on the ECoG and EMG electrode extremities (the gold wire that will be soldered to the connector) or on the skin.</li>
	<li>Fill the center of the montage with previously mixed acrylic cement. During cement solidification, remove the four surgical clamps holding the skin (and wash these immediately with delicate task wipers). 
	NOTE: Do not apply cement on the ECoG and EMG electrode extremities (the gold wire that will be soldered to the connector) or on the skin.</li>
	<li>Suture the skin at the back and the front of the montage so that the skull is not exposed (but avoid stretching the skin too much) using a suture needle (13 mm 3/8 c) and synthetic absorbable monofilament.</li>
	<li>Hold the connector above the montage with curved forceps, and carefully align the gold wire of electrodes with the connector pins. Solder electrode extremities to connector pins with the soldering iron. 
	NOTE: Proceed quickly to avoid overheating and damage to the cortical tissue. Make sure that each electrode makes good contact with the corresponding connector pin, and that the electrodes are not connected to each other.</li>
	<li>Remove the mouse from the stereotaxic frame. Cover the empty space between the connector and the head with previously mixed acrylic cement by covering all connections between electrodes and connector pins. 
	NOTE: Avoid cement infiltration inside the connector by holding the mouse with the connector above the head (head straight not leaning).</li>
	<li>Weigh the mouse and place it in a clean cage (preferably equipped with a non-meshed lid) on a heating pad (individual housing to avoid damage to the head montage). Monitor the animal regularly, and administer 0.1 mg/kg of buprenorphine subcutaneously upon awakening, and 12 h later if the animal shows signs of pain (e.g., abnormal posture, squinted eyes). 
	&#8203;NOTE: Weight gain relative to pre-surgery weight should not exceed 1.5 g.</li>
</ol>
2. Recordings
<ol>
	<li>House mice individually to avoid damage to the head montage as a result of mutual grooming as well as damage and entanglement of the recording cables. 
	NOTE: For this protocol, mice were housed with ad libitum access to food, water, and a wooden cube, and daily monitoring was conducted.</li>
	<li>Connect the mice to recording cables 2 weeks after surgery for adaptation to cabling conditions.</li>
	<li>Record ECoG signals for 24 h (or longer/shorter depending on research questions).</li>
</ol>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>21 G needle</td>
			<td>Terumo</td>
			<td>NN-2125R</td>
			<td></td>
		</tr>
		<tr>
			<td>6-channel connector</td>
			<td>Distrelec</td>
			<td>300-93-672</td>
			<td>Potential replacement for discontinued connector above</td>
		</tr>
		<tr>
			<td>C57BL6/J mice</td>
			<td>Jackson Laboratory</td>
			<td>000664 | B6</td>
			<td>Animals bred on site</td>
		</tr>
		<tr>
			<td>Pluronic F-68</td>
			<td></td>
			<td></td>
			<td>Non-ionic surfactant</td>
		</tr>
		<tr>
			<td>Gold wire 0.2 mm diameter</td>
			<td>Delta scientific</td>
			<td>920-862-41</td>
			<td>Non-insulated</td>
		</tr>
		<tr>
			<td>Hamilton syringe (10 &#956;L)</td>
			<td>Fisher Scientific</td>
			<td>14815279</td>
			<td></td>
		</tr>
		<tr>
			<td>Infusion syringe Pump CMA 402</td>
			<td>Harvard Apparatus</td>
			<td>CMA8003110</td>
			<td></td>
		</tr>
		<tr>
			<td>Injection cannula 28 G</td>
			<td>Plastics one</td>
			<td>C313l-SPCL</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Baxter</td>
			<td>CA2L9100</td>
			<td></td>
		</tr>
		<tr>
			<td>Ketamine (10 mg/mL)</td>
			<td>SANDOZ</td>
			<td>4550</td>
			<td></td>
		</tr>
		<tr>
			<td>Lead-free solder</td>
			<td>AIM</td>
			<td>SN100C</td>
			<td></td>
		</tr>
		<tr>
			<td>Lubricating ophthalmic ointment</td>
			<td>ALLERGAN</td>
			<td>210889</td>
			<td></td>
		</tr>
		<tr>
			<td>PE 50 Catheter thin wall</td>
			<td>Plastics one</td>
			<td>C232CT</td>
			<td></td>
		</tr>
		<tr>
			<td>Flat fillister head self tapping screws</td>
			<td>MORRIS</td>
			<td>FF00CE125</td>
			<td>ECoG electrode gold covered; Dimension : 1.9 mm head diameter, 1.14 mm thread major diameter, 3.6 mm length</td>
		</tr>
		<tr>
			<td>Soldering iron</td>
			<td>Weller</td>
			<td>WES51</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe 1 mL</td>
			<td>BD</td>
			<td>309659</td>
			<td></td>
		</tr>
		<tr>
			<td>Trimmer</td>
			<td>Harvard Apparatus</td>
			<td>72-9063</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylazine (20 mg/mL)</td>
			<td>Bayer</td>
			<td>2169592</td>
			<td></td>
		</tr>
		<tr>
			<td>Buprenorphine (0.3 mg/mL)</td>
			<td>CEVA</td>
			<td>57133-02</td>
			<td></td>
		</tr>
		<tr>
			<td>Curved forceps</td>
			<td>Fine science tools</td>
			<td>11001-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Delicate task wipers</td>
			<td>Kimtech</td>
			<td>34120</td>
			<td></td>
		</tr>
		<tr>
			<td>Dental acrylic cement</td>
			<td>Yates Motloid</td>
			<td>44115</td>
			<td></td>
		</tr>
		<tr>
			<td>Kelly forceps</td>
			<td>Fine science tools</td>
			<td>13002-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid acrylic</td>
			<td>Yates Motloid</td>
			<td>44119</td>
			<td></td>
		</tr>
		<tr>
			<td>Monocryl plus suture needle 13 mm 3/8c rev cutting</td>
			<td>Ethicon</td>
			<td>MCP494</td>
			<td></td>
		</tr>
		<tr>
			<td>Providone-iodine 10%</td>
			<td>Triad disposables</td>
			<td>10-8208</td>
			<td></td>
		</tr>
		<tr>
			<td>RelyX Unicem 2, Adhesive Resin Cement A2</td>
			<td>3M</td>
			<td>56849</td>
			<td></td>
		</tr>
	</tbody>
</table>

Source: Dufort-Gervais, et al. <a href="https://app.jove.com/v/61976">Electrocorticographic Recording of Cerebral Cortex Areas Manipulated Using an Adeno-Associated Virus Targeting Cofilin in Mice.</a> J. Vis. Exp. (2021)
This video demonstrates a protocol for implanting electrocorticographic electrodes in the mouse cerebral cortex to record electrical signals in response to adeno-associated viruses that target and manipulate cofilin expression.

<img alt="Figure 1" src="/files/ftp_upload/22724/22724_Figure1.jpg" /> 
Figure 1: Preparation of ECoG/EMG montage components and representative example of ECoG electrode placement. (A) An ECoG electrode: a 4 mm long, 0.2 mm diameter gold wire (non-insulated) is fused on the head of a gold-covered screw (1.9 mm head diameter, 1.14 mm thread major diameter, 3.6 mm total length) using lead-free solder. (B) EMG electrodes: two gold wires...

1. ECoG/EMG electrode implantation

	Using straight Kelly forceps, slowly screw one ECoG electrode (with straight gold wire) in the vertical axis in the ...

Take an anesthetized mouse with its skull exposed on a stereotactic frame. This mouse has been injected with a virus expressing the mutated actin-severing protein into the right cerebral cortex.
Screw an electrocorticographic electrode into the injection site.
Mark and drill the skull perpendicularly for the posterior electrode, reference electrode, and maintenance screws.
Disinfect the sites with antiseptic and block them to prevent bleeding.
Insert the screws and electrodes at the same drill angles and apply dental cement to the space between them.
Now, use light to solidify the cement.
Cover the bases of the electrodes and screws with dental cement and apply light again. Secure the assembly with acrylic cement. Suture the skin.
Connect the electrodes&#39; gold wires to the connector pins.
Cover the connector space with acrylic cement.
Allow the mouse to recover. Following recovery, record cerebral cortex signals in response to the viral injection.&#160;

31 Aufrufe. Implantation von Elektroden in einen Mauskortex für elektrokortikographische Aufzeichnungen

Serie: Implantation von Elektroden in einen Mauskortex für elektrokortikographische Aufzeichnungen - Experiment

Combined Invasive Subcortical and Non-invasive Surface Neurophysiological Recordings for the Assessment of Cognitive and Emotional Functions in Humans

In spite of the success in applying non-invasive electroencephalography (EEG), magneto-encephalography (MEG) and functional magnetic resonance imaging (fMRI) for extracting crucial information about the mechanism of the human brain, such methods remain insufficient to provide information about physiological processes reflecting cognitive and emotional functions at the subcortical level. In this respect, modern invasive clinical approaches in humans, such as deep brain stimulation (DBS), offer a tremendous possibility to record subcortical brain activity, namely local field potentials (LFPs) representing coherent activity of neural assemblies from localized basal ganglia or thalamic regions. Notwithstanding the fact that invasive approaches in humans are applied only after medical indication and thus recorded data correspond to altered brain circuits, valuable insight can be gained regarding the presence of intact brain functions in relation to brain oscillatory activity and the pathophysiology of disorders in response to experimental cognitive paradigms. In this direction, a growing number of DBS studies in patients with Parkinson&#39;s disease (PD) target not only motor functions but also higher level processes such as emotions, decision-making, attention, memory and sensory perception. Recent clinical trials also emphasize the role of DBS as an alternative treatment in neuropsychiatric disorders ranging from obsessive compulsive disorder (OCD) to chronic disorders of consciousness (DOC). Consequently, we focus on the use of combined invasive (LFP) and non-invasive (EEG) human brain recordings in assessing the role of cortical-subcortical structures in cognitive and emotional processing trough experimental paradigms (e.g. speech stimuli with emotional connotation or paradigms of cognitive control such as the Flanker task), for patients undergoing DBS treatment.

The present protocol aims at assessing cognitive-emotional functions in the basal ganglia by simultaneous neurophysiological recording of local field potentials and non-invasive brain cortical activity (EEG). The procedure is exemplified by the use of paradigms involving speech stimuli with emotional connotation or the Flanker task involving cognitive control.

Kombinierte Invasive Subcortical und Nicht-invasive Oberflächenneurophysiologische Aufnahmen zur Beurteilung von kognitiven und emotionalen Funktionen beim Menschen

In spite of the success in applying non-invasive electroencephalography (EEG), magneto-encephalography (MEG) and functional magnetic resonance imaging ...

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Verhalten

Chronic Transcranial Electrical Stimulation and Intracortical Recording in Rats

Transcranial electrical stimulation (TES) is a powerful and relatively simple approach to diffusely influence brain activity either randomly or in a closed-loop event-triggered manner. Although many studies are focusing on the possible benefits and side-effects of TES in healthy and pathologic brains, there are still many fundamental open questions regarding the mechanism of action of the stimulation. Therefore, there is a clear need for a robust and reproducible method to test the acute and the chronic effects of TES in rodents. TES can be combined with regular behavioral, electrophysiological, and imaging techniques to investigate neuronal networks in vivo. The implantation of transcranial stimulation electrodes does not impose extra constraints on the experimental design while it offers a versatile, flexible tool to manipulate brain activity. Here we provide a detailed, step-by-step protocol to fabricate and implant transcranial stimulation electrodes to influence brain activity in a temporally constrained manner for months.

This detailed protocol describes transcranial stimulation electrode placement on the temporal bone in order to investigate the short- and long-term effects of transcranial electrical stimulation in freely moving rats.

Chronische Transkraniellen Elektrostimulation und Intracortical Aufnahme bei Ratten

Transcranial electrical stimulation (TES) is a powerful and relatively simple approach to diffusely influence brain activity either randomly or in a ...

Neurowissenschaften

Chronic Implantation of Whole-cortical Electrocorticographic Array in the Common Marmoset

Electrocorticography (ECoG) allows the monitoring of electrical field potentials from the cerebral cortex with high spatiotemporal resolution. Recent development of thin, flexible ECoG electrodes has enabled conduction of stable recordings of large-scale cortical activity. We have developed a whole-cortical ECoG array for the common marmoset. The array continuously covers almost the entire lateral surface of cortical hemisphere, from the occipital pole to the temporal and frontal poles, and it captures whole-cortical neural activity in one shot. This protocol describes a chronic implantation procedure of the array in the epidural space of the marmoset brain. Marmosets have two advantages regarding ECoG recordings, one being the homologous organization of anatomical structures in humans and macaques, including frontal, parietal, and temporal complexes. The other advantage is that the marmoset brain is lissencephalic and contains a large number of complexes, which are more difficult to access in macaques with ECoG, that are exposed to the brain surface.These features allow direct access to most cortical areas beneath the surface of the brain. This system provides an opportunity to investigate global cortical information processing with high resolutions at a sub-millisecond order in time and millimeter order in space.

We have developed a whole-cortical electrocorticographic array for the common marmoset that continuously covers almost the entire lateral surface of cortex, from the occipital pole to the temporal and frontal poles. This protocol describes a chronic implantation procedure of the array in the epidural space of the marmoset brain.

Chronische Implantation des gesamten kortikalen Electrocorticographic Arrays in der Weißbüschelaffe

Electrocorticography (ECoG) allows the monitoring of electrical field potentials from the cerebral cortex with high spatiotemporal resolution. Recent ...

Implantation of Electrodes into a Mouse Cortex for Electrocorticographic Recordings

Transkript

Implantation of Electrodes into a Mouse Cortex for Electrocorticographic Recordings