The research was supported by the National Natural Science Foundation of China (No. 82030037, 81871009) and Beijing Municipal Health Commission (11000022T000000444685). We thank TopEdit (www.topeditsci.com) for its linguistic assistance during the preparation of this manuscript.

This experiment was approved by the Experimental Animal Ethics Committee of Xuanwu Hospital, Capital Medical University. All mice were kept in the animal laboratory of Xuanwu Hospital, Capital Medical University. This protocol is divided into four parts. The first two parts introduce the method of building the electrode and the electric circuit using a slip ring to connect the electrodes and the EEG recording/stimulation equipment. The third part describes the operation method of electrode implantation, and the fourth part presents the EEG recording and stimulation parameters used for the amygdala epilepsy model.
1. Fabrication of electrodes
<ol>
	<li>Keep the following previously prepared materials ready: two 3 cm long pieces of Teflon-coated tungsten wire (bare diameter: 76.2 &#181;m), one piece of silver wire (bare diameter: 127 &#181;m) of the same length, and one set of 2 x 2 gauged row pins.</li>
	<li>Use a lighter to burn one end of each tungsten wire to remove 5 mm of the insulation coating. 
	NOTE: The tungsten wire with the insulation removed turns black; this part of the tungsten wire is referred to as the upper end.</li>
	<li>Peel a section of ultrafine multi-strand wire and wrap it from the bottom to the upper end where it starts to get dark, continuing to the top. Combine this superfine wire (has a soft texture) with the tungsten wire by pinching one end and gently twisting the other end, which enables the two materials to be easily entwined together.</li>
	<li>Gently pull to ensure that they are tightly wrapped and cut off excess superfine wire. Try to keep the tungsten wire straight throughout the process.</li>
	<li>Fix the row pin to the clamp on the welding table with the longer side of the pins facing outward. Use the syringe needle to pick up some solder paste and apply it to the pins. Heat the welding torch to 320 &#176;C; melt and smear some lead-free tin wire with the torch tip.</li>
	<li>Overlap the upper end of the tungsten wire with one needle of the row pins and use the solder on the torch to bond the tungsten wire to the pin. 
	NOTE: It would be very difficult to weld the tungsten wire with the pins directly without the help of the superfine wire.</li>
	<li>Weld another tungsten wire and another silver wire to the row pin in the same way so that each wire corresponds to a needle (see Figure 1,i).</li>
	<li>Cut two heat-shrinkable tubes slightly longer than the upper end of the tungsten wire. Put them on the solder joint of two tungsten wires, ensuring that the conductive part is fully covered in the tube so that the circuit of the two tungsten wires is not placed in series. 
	NOTE: Although there are three wires, if two of them are insulated, the three wires will not be in series; a tube can also be added to the silver wire.</li>
	<li>Remove the electrode from the welding table clamp and hold the electrode gently with large pliers, as it is easy for electrodes to lose their shape when heating the shrinkable tube, using a good thermal conductivity clamp with slightly more force.</li>
	<li>Turn on the air duct and heat until a temperature of 320 &#176;C is reached. Blow the heat-shrinkable tube for several seconds until it is tightened (see Figure 1,ii).</li>
	<li>If the needles separate from the plastic body during the welding process, splice the welding part and the plastic body with a hot melt adhesive (see Figure 1,iii). Be careful not to smear it on the interface as this would affect the interface insertion.</li>
	<li>Hold the two tungsten wires and twist them together, keeping their ends apart (see Figure 1,iv). Trim the twisted tungsten wires to approximately 10 mm in length so that the separation at the ends does not exceed 0.5 mm. 
	&#8203;NOTE: This step can also be performed before electrode implantation to allow flexible adjustment of electrode length.</li>
	<li>Heat the glue gun and apply the glue evenly around the electrode.</li>
	<li>Check the electrodes with a multimeter: place one bar of the multimeter on the unwelded side of the row pins, and gently touch the end of tungsten wire or silver wire to the other bar, checking whether the circuit is smooth. Ensure that the lines are not placed in series.</li>
</ol>
2. Slip ring connection and circuit description
NOTE: When the electrodes on the mice are plugged into an EEG device via cables in a free-moving condition, the cables can become tangled as the mice move and turn around. This causes the cables to become shorter, eventually hindering the mice from moving or causing the cables to fall off their heads. In the method described here, a four-channel slip ring is introduced to prevent the cables from falling off. The four channels are represented in four colors in Figure 1B.
<ol>
	<li>Peel off 5 mm of the insulation skin at each end to expose the metal wire inside.</li>
	<li>Add a section of heat-shrinkable tube to each stator wire.</li>
	<li>Weld each wire with the EEG device connector plug.</li>
	<li>Shrink the heat-shrinkable tube with hot air.</li>
	<li>Add a section of heat-shrinkable tube to each rotor wire.</li>
	<li>Screw the conducting parts of the red and orange wires together and weld them to a joint in the header to fit the row pin.</li>
	<li>Weld the other two wires on the header to each joint. 
	&#8203;NOTE: The brown channel that corresponds to the silver wire is connected to the EEG device for grounding. The red and orange channels receive signals from the same tungsten wire, and the orange channel serves as a reference for the EEG device. The signals in the red channel are meaningless, but they must coexist with the black channel to form a current stimulus. The signals in the black channel are the real electrical signals in the brain. Different circuits can be designed with multi-channel slip rings to suit different devices.</li>
</ol>
3. Surgery for implantation
<ol>
	<li>Animals
	<ol>
		<li>Use 8-week-old C57BL/6 wild-type male mice, weighing 24-26 g, for surgeries.</li>
		<li>House them with a 12 h light-dark cycle (light time: 8:00-20:00) in a temperature-controlled environment (22 &#177; 1 &#176;C) and provide water and feed ad libitum.</li>
		<li>Use an extra heat mat to keep the animals warm during the surgery.</li>
		<li>After the surgery, inject meloxicam subcutaneously (10 mg/kg) as the first administration of analgesics. Then, place the animals in separate cages to optimize recovery. Add meloxicam to the animal&#39;s diet for the first week after surgery.</li>
		<li>After the experiment, infuse the left ventricles of the mice with 4% paraformaldehyde under anesthesia, and collect the brain tissues for histological verification of the electrode target.</li>
	</ol>
	</li>
	<li>Weigh the mouse and anesthetize it by intraperitoneal injection of 1% pentobarbital solution. Sterilize all the surgical instruments and consumables to be used, including drill bits, electrodes, dental cement, etc., by autoclaving.</li>
	<li>When the mouse is completely anesthetized, shave the hair from the eye to the ear area with a razor.</li>
	<li>Fix the mouse on the stereotaxic frame. Put the front upper teeth into the incisor bar and insert both ear bars equally deeply into the ears. Apply erythromycin eye ointment to the eyes to prevent dryness and blindness caused by a bright light during surgery.</li>
	<li>Disinfect the surgical area with three alternating swabs of iodophor and 75% alcohol in a circular motion. Then, make a sagittal incision forward from the middle of this incision, and cut off the skin on either side of the incision to create a triangular window.</li>
	<li>Roll a small piece of cotton into a ball and wet it with 3% hydrogen peroxide. Remove the soft tissue attached to the skull by gently rubbing the exposed area with a small cotton ball until the anterior and posterior fontanelle are clearly seen.</li>
	<li>Adjust the anterior and posterior heights so that the anterior and posterior fontanelle is in the horizontal position. Consider the position of the anterior fontanelle to be the origin of the axes.</li>
	<li>Fix a stainless-steel screw to the left cerebellar skull, using a drill to create a flat surface. Ensure that the screw protrudes halfway out of the skull.</li>
	<li>Ensure the coordinates for the amygdala kindling are &#8722;1.67 mm posterior, &#8722;2.7 mm lateral, and &#8722;4.9 mm ventral from the bregma. Adjust the stereotaxic device to locate this spot and mark it.</li>
	<li>Drill a hole on the marked spot with a 0.5 mm diameter skull drill.</li>
	<li>Fix the electrodes to the locating rod of the stereotaxic device, place the electrode vertically above the hole, and drop the position to &#8722;4.9 mm slowly. Wrap the silver wire around the screw three times, taking care not to shake the electrode body during operation.</li>
	<li>Mix the dental cement and gently apply it to the electrode and skull surface. When the dental cement hardens, modify the outside until the cement that encloses the fixed electrode turns into a cone.</li>
	<li>When the cement has hardened, release the electrode from the stereotaxic device. Subcutaneously administer meloxicam 10mg/kg to relieve discomfort caused by pain in animals. Administer meloxicam to animal food for analgesic effect in the first week after surgery. Remove the mouse and place it back in the cage, keeping it separate from the other mice.</li>
</ol>
4. Electrical kindling
<ol>
	<li>Allow the mice to rest for at least 1 week after surgery before kindling to allow for postoperative recovery and to allow the inflammation to subside. 
	NOTE: In general, mice that have not recovered adequately do not respond well to kindling.</li>
	<li>Put the mouse in a customized box with slip-ring cables connecting the electrode on the mouse&#39;s head and the EEG device. Run the cable through a hole in the lid of the box, and adjust the length left in the box to allow the mouse to move freely.</li>
	<li>Turn on the EEG device and check whether it is working properly. Set the stimulator to deliver 1 ms monophasic square-wave pulses at 60 Hz for a 1 s train duration.</li>
	<li>Start with a current intensity of 50 &#181;A for the first stimulation; monitor the EEG for after-discharge, which is characterized by high-frequency spikes. If no after-discharge is observed, add 25 &#181;A to the next stimulus, and continue this process every 10 min until an after-discharge is observed and lasts 5 s. 
	NOTE: If the experiment does not require a discharge, step 4.4 can be skipped; 300 &#181;A is strong enough for kindling.</li>
	<li>Stimulate the mouse with the current intensity determined in step 4.3 every 15 min, no more than 20 times a day.</li>
	<li>Monitor the behavioral responses to the stimulus. 
	NOTE: The occurrence of three consecutive grade V episodes is considered full kindling, combined with Racine rank standard17.</li>
</ol>

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The authors have no conflicts of interest to disclose.

Epilepsy is a group of diseases with multiple manifestations and diverse causes18; it should be noted that no single model can be used for all types of epilepsy, and researchers must select an appropriate model for their specific study. The present study introduces one of the most accessible methods of electrode fabrication. Various parts of this method can be adjusted to adapt to different experimental conditions.
This method utilizes electrodes with both stimulating a...

Temporal lobe epilepsy (TLE) is the most prevalent type of epilepsy and has a high risk of conversion into drug-resistant epilepsy. Surgery, such as selective amygdalohippocampectomy, is an effective treatment for TLE, and the epileptogenesis and ictogenesis of the disease are still under investigation1,2. Pathogenesis of TLE has been shown to occur not only in the hippocampus but also extensively in the amygdala3,4. For example, both amygdala sclerosis and amygdala enlargement have been frequently reported as the origins of TLE seizures5,6. The importance of the amygdala cannot be underestimated; an amygdala model is essential for the study of epileptogenesis, and a clear illustration of this model is urgently needed.
Several approaches have been proposed to induce seizures in animal models. In the past, convulsant drugs were injected intraperitoneally at an early stage7. Although this method was convenient, the location of epileptic foci was uncertain. With the development of stereotactic technology and a detailed animal brain atlas, intracranial drug injection was applied to solve the problem of localization8. However, a lack of intervention for severe seizures during the acute stage resulted in a high mortality rate, and chronic spontaneous seizures were accompanied by the problem of unstable interictal and seizure frequency9,10. Finally, the electrical kindling method was developed; this method periodically stimulates specific brain regions several times, allowing seizures to be induced with definite control of both the location and the onset time11.
An advantage of this method is that the intracranial implantation of electrodes is minimally invasive12. Furthermore, the severity of the seizure is controllable by the termination of the stimuli, reducing the mortality caused by the seizures. These changes solved the shortcomings of the previous approaches. Notably, this model can adequately mimic human seizures and is especially suitable for the study of status epilepticus (SE) because of its ability to induce SE quickly13. It can also be used for anti-epileptic drug screening14 and in studies on the mechanism of epilepsy. Finally, it is well known that the amygdala is closely associated with memory modulation, reward processing, and emotion15. Disorders of these mental functions are often encountered in epileptic patients and, thus, the amygdala epilepsy model may be a better choice for studying emotional problems in epilepsy16.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Alexa Fluor 488-conjugated Donkey anti-Rabbit IgG</td>
			<td>invitrogen</td>
			<td>A-21206</td>
			<td></td>
		</tr>
		<tr>
			<td>c-Fos antibody</td>
			<td></td>
			<td>ab222699</td>
			<td></td>
		</tr>
		<tr>
			<td>Cranial drill</td>
			<td>SANS</td>
			<td>SA302</td>
			<td></td>
		</tr>
		<tr>
			<td>dental cement</td>
			<td>NISSIN</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>EEG recording and stimulation equipment</td>
			<td>Neuracle Technology (Changzhou) Co., Ltd</td>
			<td>NSHHFS-210803</td>
			<td></td>
		</tr>
		<tr>
			<td>lead-free tin wire</td>
			<td>BAKON</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pin header/Female header</td>
			<td>XIANMISI</td>
			<td></td>
			<td>spacing of 1.27 mm</td>
		</tr>
		<tr>
			<td>Silver wire</td>
			<td>A-M systems</td>
			<td>786000</td>
			<td></td>
		</tr>
		<tr>
			<td>Slip ring</td>
			<td>Senring Electronics Co.,Ltd</td>
			<td>SNM008-04</td>
			<td></td>
		</tr>
		<tr>
			<td>Tungsten wire</td>
			<td>A-M systems</td>
			<td>796000</td>
			<td></td>
		</tr>
		<tr>
			<td>ultrafine multi-stand wire</td>
			<td>Shenzhen Chengxing wire and cable</td>
			<td>UL10064-FEP</td>
			<td></td>
		</tr>
		<tr>
			<td>welding equipment</td>
			<td>BAKON</td>
			<td>BK881</td>
			<td></td>
		</tr>
	</tbody>
</table>

using a bipolar electrode to create a temporal lobe epilepsy mouse model by electrical kindling of the amygdala

The amygdala is one of the most common origins of seizures, and the amygdala mouse model is essential for the illustration of epilepsy. However, few studies have described the experimental protocol in detail. This paper illustrates the whole process of amygdala electrical kindling epilepsy model making, with the introduction of a method of bipolar electrode fabrication. This electrode can both stimulate and record, reducing brain injury caused by implanting separate electrodes for stimulation and recording. For long-term electroencephalogram (EEG) recording purposes, slip rings were used to eliminate the record interruption caused by cable tangles and falling off.
After periodic stimulation (60 Hz, 1 s every 15 min) of the basolateral amygdala (AP: 1.67 mm, L: 2.7 mm, V: 4.9 mm) for 19.83 &plusmn; 5.742 times, full kindling was observed in six mice (defined as induction of three continuous grade V episodes classified by Racine's scale). An intracranial EEG was recorded throughout the entire kindling process, and an epileptic discharge in the amygdala lasting 20-70 s was observed after kindling. Therefore, this is a robust protocol for modeling epilepsy originating from the amygdala, and the method is suitable for revealing the role of the amygdala in temporal lobe epilepsy. This research contributes to future studies on the mechanisms of mesial temporal lobe epilepsy and novel antiepileptogenic drugs.

The electrode and circuit enable the EEG to be recorded and function as a stimulation (Figure 1); this setup avoids the complexity of implanting recording and stimulating electrodes separately and minimizes damage to the brain tissue. The application of slip rings allows electrode connection with all types of devices.
We performed electrode implantation surgery on six healthy adult male C57BL/6 mice, and electrical stimulation was performed 2 weeks after surgery. ...

Watch this Scientific Journal Video about Using a Bipolar Electrode to Create a Temporal Lobe Epilepsy Mouse Model by Electrical Kindling of the Amygdala at JoVE.com

Using a Bipolar Electrode to Create a Temporal Lobe Epilepsy Mouse Model by Electrical Kindling of the Amygdala

The amygdala plays a key role in temporal lobe epilepsy, which originates in and propagates from this structure. This article provides a detailed description of the fabrication of deep brain electrodes with both recording and stimulating functions. It introduces a model of medial temporal lobe epilepsy originating from the amygdala.

The amygdala is one of the most common origins of seizures, and the amygdala mouse model is essential for the illustration of epilepsy. However, few ...

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2.3K Views.  Xuanwu Hospital Capital Medical University. The amygdala plays a key role in temporal lobe epilepsy, which originates in and propagates from this structure. This article provides a detailed description of the fabrication of deep brain electrodes with both recording and stimulating functions. It introduces a model of medial temporal lobe epilepsy originating from the amygdala.

Video: Using a Bipolar Electrode to Create a Temporal Lobe Epilepsy Mouse Model by Electrical Kindling of the Amygdala

Identification of Olfactory Volatiles using Gas Chromatography-Multi-unit Recordings (GCMR) in the Insect Antennal Lobe

All organisms inhabit a world full of sensory stimuli that determine their behavioral and physiological response to their environment. Olfaction is especially important in insects, which use their olfactory systems to respond to, and discriminate amongst, complex odor stimuli. These odors elicit behaviors that mediate processes such as reproduction and habitat selection1-3. Additionally, chemical sensing by insects mediates behaviors that are highly significant for agriculture and human health, including pollination4-6, herbivory of food crops7, and transmission of disease8,9. Identification of olfactory signals and their role in insect behavior is thus important for understanding both ecological processes and human food resources and well-being.
	To date, the identification of volatiles that drive insect behavior has been difficult and often tedious. Current techniques include gas chromatography-coupled electroantennogram recording (GC-EAG), and gas chromatography-coupled single sensillum recordings (GC-SSR)10-12. These techniques proved to be vital in the identification of bioactive compounds. We have developed a method that uses gas chromatography coupled to multi-channel electrophysiological recordings (termed 'GCMR') from neurons in the antennal lobe (AL; the insect's primary olfactory center)13,14. This state-of-the-art technique allows us to probe how odor information is represented in the insect brain. Moreover, because neural responses to odors at this level of olfactory processing are highly sensitive owing to the degree of convergence of the antenna's receptor neurons into AL neurons, AL recordings will allow the detection of active constituents of natural odors efficiently and with high sensitivity. Here we describe GCMR and give an example of its use.
	Several general steps are involved in the detection of bioactive volatiles and insect response. Volatiles first need to be collected from sources of interest (in this example we use flowers from the genus Mimulus (Phyrmaceae)) and characterized as needed using standard GC-MS techniques14-16. Insects are prepared for study using minimal dissection, after which a recording electrode is inserted into the antennal lobe and multi-channel neural recording begins. Post-processing of the neural data then reveals which particular odorants cause significant neural responses by the insect nervous system.
	Although the example we present here is specific to pollination studies, GCMR can be expanded to a wide range of study organisms and volatile sources. For instance, this method can be used in the identification of odorants attracting or repelling vector insects and crop pests. Moreover, GCMR can also be used to identify attractants for beneficial insects, such as pollinators. The technique may be expanded to non-insect subjects as well.

Identification of Olfactory Volatiles using Gas Chromatography-Multi-unit Recordings GCMR in the Insect Antennal Lobe

Olfactory cues mediate many different behaviors in insects, and are often complex mixtures comprised of tens to hundreds of volatile compounds. Using gas chromatography with multi-channel recording in the insect antennal lobe, we describe a method for the identification of bioactive compounds.

All  organisms inhabit a world full of sensory stimuli that determine their  behavioral and physiological response to their environment. Olfaction is ...

Trypsin Digest Protocol to Analyze the Retinal Vasculature of a Mouse Model

Trypsin digest is the gold standard method to analyze the retinal vasculature 1-5. It allows visualization of the entire network of complex three-dimensional retinal blood vessels and capillaries by creating a two-dimensional flat-mount of the interconnected vascular channels after digestion of the non-vascular components of the retina. This allows one to study various pathologic vascular changes, such as microaneurysms, capillary degeneration, and abnormal endothelial to pericyte ratios. However, the method is technically challenging, especially in mice, which have become the most widely available animal model to study the retina because of the ease of genetic manipulations 6,7. In the mouse eye, it is particularly difficult to completely remove the non-vascular components while maintaining the overall architecture of the retinal blood vessels. To date, there is a dearth of literature that describes the trypsin digest technique in detail in the mouse. This manuscript provides a detailed step-by-step methodology of the trypsin digest in mouse retina, while also providing tips on troubleshooting difficult steps.

Trypsin digest is one of the most commonly used methods to analyze retinal vasculature. This manuscript describes the method in detail, including key alterations to optimize the technique and remove the non-vascular tissue while preserving the overall architecture of the vessels.

Trypsin digest is the gold standard method to analyze the retinal vasculature 1-5. It allows visualization of the entire network of complex ...

A Comprehensive Protocol for Manual Segmentation of the Medial Temporal Lobe Structures

The present paper describes a comprehensive protocol for manual tracing of the set of brain regions comprising the medial temporal lobe (MTL): amygdala, hippocampus, and the associated parahippocampal regions (perirhinal, entorhinal,&#160;and parahippocampal proper). Unlike most other tracing protocols available, typically focusing on certain MTL areas (e.g., amygdala and/or hippocampus), the integrative perspective adopted by the present tracing guidelines allows for clear localization of all MTL subregions. By integrating information from a variety of sources, including extant tracing protocols separately targeting various MTL structures, histological reports, and brain atlases, and with the complement of illustrative visual materials, the present protocol provides an accurate, intuitive, and convenient guide for understanding the MTL anatomy. The need for such tracing guidelines is also emphasized by illustrating possible differences between automatic and manual segmentation protocols. This knowledge can be applied toward research involving not only structural MRI investigations but also structural-functional colocalization and fMRI signal extraction from anatomically defined ROIs, in healthy and clinical groups alike.

The present work provides a comprehensive set of guidelines for manually tracing the medial temporal lobe (MTL) structures. This protocol can be applied to research involving structural and/or combined structural-functional magnetic resonance imaging (MRI) investigations of the MTL, in both healthy and clinical groups.

The present paper describes a comprehensive protocol for manual tracing of the set of brain regions comprising the medial temporal lobe (MTL): amygdala, ...

Pentylenetetrazole-Induced Kindling Mouse Model

Pentylenetetrazole (PTZ) is a GABA-A receptor antagonist. An intraperitoneal injection of PTZ into an animal induces an acute, severe seizure at a high dose, whereas sequential injections of a subconvulsive dose have been used for the development of chemical kindling, an epilepsy model. A single low-dose injection of PTZ induces a mild seizure without convulsion. However, repetitive low-dose injections of PTZ decrease the threshold to evoke a convulsive seizure. Finally, continuous low-dose administration of PTZ induces a severe tonic-clonic seizure. This method is simple and widely applicable to investigate the pathophysiology of epilepsy, which is defined as a chronic disease that involves repetitive seizures. This chemical kindling protocol causes repetitive seizures in animals. With this method, vulnerability to PTZ-mediated seizures or the degree of aggravation of epileptic seizures was estimated. These advantages have led to the use of this method for screening anti-epileptic drugs and epilepsy-related genes. In addition, this method has been used to investigate neuronal damage after epileptic seizures because the histological changes observed in the brains of epileptic patients also appear in the brains of chemical-kindled animals. Thus, this protocol is useful for conveniently producing animal models of epilepsy.

This protocol describes a method of chemical kindling with pentylenetetrazole and provides a mouse model of epilepsy. This protocol can also be used to investigate vulnerability to seizure induction and pathogenesis after epileptic seizures in mice.

Pentylenetetrazole (PTZ) is a GABA-A receptor antagonist. An intraperitoneal injection of PTZ into an animal induces an acute, severe seizure at a high ...

Behavioral And Physiological Analysis In A Zebrafish Model Of Epilepsy

Epilepsy represents one of the most common neurological disorders, affecting an estimated 50 million people worldwide. Recent advances in genetic research have uncovered a large spectrum of genes implicated in various forms of epilepsy, highlighting the heterogeneous nature of this disorder. Appropriate animal models are essential for investigating the pathological mechanisms triggered by genetic mutations implicated in epilepsy and for developing specialized, targeted therapies. In recent years, zebrafish has emerged as a valuable vertebrate organism for modeling epilepsies, with the use of both genetic manipulation and exposure to known epileptogenic drugs, such as pentylenetetrazole (PTZ), to identify novel anti-epileptic therapeutics. Deleterious mutations in the mTOR regulator DEPDC5 have been associated with various forms of focal epilepsies and knock-down of the zebrafish orthologue causes hyperactivity associated with spontaneous seizure-like episodes, as well as enhanced electrographic activity and characteristic turn wheel swimming. Here, we described the method involved in generating the DEPDC5 loss-of-function model and illustrate the protocol for assessing motor activity at 28 and 48 h post fertilization (hpf), as well as a method for recording field activity in the zebrafish optic tectum. An illustration of the effect of the epileptogenic drug PTZ on neuronal activity over time is also provided.

Here, we present a protocol for the development and the characterization of a zebrafish model of epilepsy resulting from the transient inhibition of the DEPDC5 gene.

Epilepsy represents one of the most common neurological disorders, affecting an estimated 50 million people worldwide. Recent advances in genetic research ...

Successful In vivo Calcium Imaging with a Head-Mount Miniaturized Microscope in the Amygdala of Freely Behaving Mouse

In vivo real-time monitoring of neuronal activities in freely moving animals is one of key approaches to link neuronal activity to behavior. For this purpose, an in vivo imaging technique that detects calcium transients in neurons using genetically encoded calcium indicators (GECIs), a miniaturized fluorescence microscope, and a gradient refractive index (GRIN) lens has been developed and successfully applied to many brain structures1,2,3,4,5,6. This imaging technique is particularly powerful because it enables chronic simultaneous imaging of genetically defined cell populations for a long-term period up to several weeks. Although useful, this imaging technique has not been easily applied to brain structures that locate deep within the brain such as amygdala, an essential brain structure for emotional processing and associative fear memory7. There are several factors that make it difficult to apply the imaging technique to the amygdala. For instance, motion artifacts usually occur more frequently during the imaging conducted in the deeper brain regions because a head-mount microscope implanted deep in the brain is relatively unstable. Another problem is that the lateral ventricle is positioned close to the implanted GRIN lens and its movement during respiration may cause highly irregular motion artifacts that cannot be easily corrected, which makes it difficult to form a stable imaging view. Furthermore, because cells in the amygdala are usually quiet at a resting or anesthetized state, it is hard to find and focus the target cells expressing GECI in the amygdala during baseplating procedure for later imaging. This protocol provides a helpful guideline for how to efficiently target cells expressing GECI in the amygdala with head-mount miniaturized microscope for successful in vivo calcium imaging in such a deeper brain region. It is noted that this protocol is based on a particular system (e.g., Inscopix) but not restricted to it.

In vivo microendoscopic calcium imaging is an invaluable tool that enables real-time monitoring of neuronal activities in freely behaving animals. However, applying this technique to the amygdala has been difficult. This protocol aims to provide a useful guideline for successfully targeting amygdala cells with a miniaturized microscope in mice.

In vivo real-time monitoring of neuronal activities in freely moving animals is one of key approaches to link neuronal activity to behavior. For this ...

A Behavioral Screen for Heat-Induced Seizures in Mouse Models of Epilepsy

Transgenic mouse models have proved to be powerful tools in studying various aspects of human neurological disorders, including epilepsy. The SCN1A-associated genetic epilepsies comprise a wide spectrum of seizure disorders with incomplete penetrance and clinical variability. SCN1A mutations can result in a large variety of seizure phenotype ranging from simple, self-limited fever-associated febrile seizures (FS), moderate-level genetic epilepsy with febrile seizures plus (GEFS+) to more severe Dravet Syndrome (DS). Although FS are commonly seen in children below 6-7 years of age who do not have genetic epilepsy, FS in GEFS+ patients continue to occur into adulthood. Traditionally, experimental FS have been induced in mice by exposing the animal to a stream of dry air or heating lamps, and the rate of change in body temperature is often not well controlled. Here, we describe a custom-built heating chamber, with a plexiglass front, that is fitted with a digital temperature controller and a heater-equipped electric fan, which can send heated forced air into the test arena in a temperature-controlled manner. The body temperature of a mouse placed in the chamber, monitored through a rectal probe, can be increased to 40-42 &#176;C in a reproducible manner by increasing the temperature inside the chamber. Continual visual monitoring of the animals during the heating period demonstrates induction of heat-induced seizures in mice carrying an FS mutation at a body temperature that does not elicit behavioral seizures in wild-type litter mates. Animals can be easily removed from the chamber and placed on a cooling pad to rapidly return body temperature to normal. This method provides for a simple, rapid, and reproducible screening protocol for the occurrence of heat-induced seizures in epilepsy mouse models.

The goal of the method is to screen for hyperthermia or heat-induced seizures in mouse models. The protocol describes the use of a custom-built chamber with continuous monitoring of the body temperature to determine whether elevated body temperature leads to seizures.

Transgenic mouse models have proved to be powerful tools in studying various aspects of human neurological disorders, including epilepsy. The ...

Preparation and Implantation of Electrodes for Electrically Kindling VGAT-Cre Mice to Generate a Model for Temporal Lobe Epilepsy

It was discovered that electrical kindling of VGAT-Cre mice led to the spontaneous motor and electrographic seizures. A recent paper focused on how unique VGAT-Cre mice were used in developing spontaneous recurring seizures (SRS) after kindling and a likely mechanism - insertion of Cre into the VGAT gene - disrupted its expression and reduced GABAergic tone. The present study extends these observations to a larger cohort of mice, focusing on key issues such as how long the SRS continues after kindling and the effect of the animal's sex and age. This report describes the protocols for the following key steps: making headsets with hippocampal depth electrodes for electrical stimulation and for reading the electroencephalogram; surgery to affix the headset securely on the mouse's skull so that it does not fall off; and key details of the electrical kindling protocol such as duration of the pulse, frequency of train, duration of train, and amount of current injected. The kindling protocol is robust in that it reliably leads to epilepsy in most VGAT-Cre mice, providing a new model to test for novel antiepileptogenic drugs.

This report describes the methods to generate a model of temporal lobe epilepsy based on the electrical kindling of transgenic VGAT-Cre mice. Kindled VGAT-Cre mice may be useful in determining what causes epilepsy and for screening novel therapies.

It was discovered that electrical kindling of VGAT-Cre mice led to the spontaneous motor and electrographic seizures. A recent paper focused on how unique ...

Registration of Calcium Transients in Mouse Neuromuscular Junction with High Temporal Resolution using Confocal Microscopy

Estimation of the presynaptic calcium level is a key task in studying synaptic transmission since calcium entry into the presynaptic cell triggers a cascade of events leading to neurotransmitter release. Moreover, changes in presynaptic calcium levels mediate the activity of many intracellular proteins and play an important role in synaptic plasticity. Studying calcium signaling is also important for finding ways to treat neurodegenerative diseases. The neuromuscular junction is a suitable model for studying synaptic plasticity, as it has only one type of neurotransmitter. This article describes the method for loading a calcium-sensitive dye through the cut nerve bundle into the mice's motor nerve endings. This method allows the estimation of all parameters related to intracellular calcium changes, such as basal calcium level and calcium transient. Since the influx of calcium from the cell exterior into the nerve terminals and its binding/unbinding to the calcium-sensitive dye occur within the range of a few milliseconds, a speedy imaging system is required to record these events. Indeed, high-speed cameras are commonly used for the registration of fast calcium changes, but they have low image resolution parameters. The protocol presented here for recording calcium transient allows extremely good spatial-temporal resolution provided by confocal microscopy.

The protocol describes the method of loading a fluorescent calcium dye through the cut nerve into mouse motor nerve terminals. In addition, a unique method for recording fast calcium transients in the peripheral nerve endings using confocal microscopy is presented.

Estimation of the presynaptic calcium level is a key task in studying synaptic transmission since calcium entry into the presynaptic cell triggers a ...

A Model for Epilepsy of Infectious Etiology using Theiler's Murine Encephalomyelitis Virus

One of the main causes of epilepsy is an infection of the central nervous system (CNS); approximately 8% of patients who survive such an infection develop epilepsy as a consequence, with rates being significantly higher in less economically developed countries. This work provides an overview of modeling epilepsy of infectious etiology and using it as a platform for novel antiseizure compound testing. A protocol of epilepsy induction by non-stereotactic intracerebral injection of Theiler's murine encephalomyelitis virus (TMEV) in C57BL/6 mice is presented, which replicates many of the early and chronic clinical symptoms of viral encephalitis and subsequent epilepsy in human patients. The clinical evaluation of mice during encephalitis to monitor seizure activity and detect the potential antiseizure effects of novel compounds is described. Furthermore, histopathological consequences of viral encephalitis and seizures such as hippocampal damage and neuroinflammation are shown, as well as long-term consequences such as spontaneous epileptic seizures. The TMEV model is one of the first translational, infection-driven, experimental platforms to allow for the investigation of the mechanisms of epilepsy development as a consequence of CNS infection. Thus, it also serves to identify potential therapeutic targets and compounds for patients at risk of developing epilepsy following a CNS infection.

Intracerebral infection with the Theiler's murine encephalomyelitis virus (TMEV) in C57BL/6 mice replicates many of the early and chronic clinical symptoms of viral encephalitis and subsequent epilepsy in human patients. This paper describes the virus infection, symptoms, and histopathology of the TMEV model.

One of the main causes of epilepsy is an infection of the central nervous system (CNS); approximately 8% of patients who survive such an infection develop ...