recording electrically-evoked auditory brainstem responses in a deafened mouse

Recording Electrically-Evoked Auditory Brainstem Responses in a Deafened Mouse

To insert the cochlear implant electrode array, place the retractor tool back into the incision to re-access the bulla, and insert the electrode array into the scala tympani, at a depth such that the fourth platinum ring of the array is located just inside the round window.
The insertion of the electrode array can also be tricky, so take your time to find a good insertion angle using one forcep tool, the lead wire, and another to insert the array.
Coil the lead wire inside the bulla, and glue the wire to the tissue above the bulla.
After carefully removing the retractor, enclosing the insertion with tissue glue, use a scalpel to make a 0.5-millimeter incision in the neck, perpendicular to the line between where the active and reference aVR electrodes will be. Place the ground ball in the insertion, and connect the electrode array board to the Animal Stimulator Platform.
To perform an electric aVR, place the electrodes as previously demonstrated, and open the Animal Stimulator Platform Software. Then, define the electric pulse stimulation paradigm, and present the electric pulse trains recording the evoked electric eABR responses continuously via the TDT headstage pre-amplifier and auditory processor.

recording-electrically-evoked-auditory-brainstem-responses-deafened

Universidad de Cartagena UDEC

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All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. Insertion of cochlear implant (CI) Electrode Array
NOTE: The intracochlear electrode array consists of four platinum bands (&#216;0.2 mm)&#160;&#160;&#160; with platinum/iridium parylene insulated wire shielded in a silicone tube (Figure 1).
<ol>
	<li>Place the retractor tool in the incision to re-access the bulla.</li>
	<li>Insert the electrode array into the round window (scala tympani) at a depth where the 4th platinum ring is located just inside the round window. This gives an insertion depth of ~2 mm, corresponding to an intracochlear position at ~30 kHz.</li>
	<li>Coil the lead wire inside the bulla and glue the wire to the tissue above the bulla. Coiling the wire helps to keep the array in place throughout the experiment.</li>
	<li>Carefully remove the retractor and close the insertion with tissue glue.</li>
	<li>Make a small incision (0.5 mm) in the neck perpendicular to the line between where the active and reference auditory brainstem response (ABR) electrodes will be using a tissue scissor. Place the platinum ground ball in the subcutaneous pocket and close the small incision with tissue glue (Figure 2).</li>
	<li>Connect the electrode array board to the Animal Stimulator Platform (ASP).</li>
</ol>
2. Electric Auditory Brainstem Response (eABR)
NOTE: An Animal Stimulator Platform is used to electrically stimulate the electrode array. Other current sources and software systems can be used.
<ol>
	<li>Clean the ABR electrodes with 70% ethanol solution. Place the electrodes under the skin: active (Ch1) on the vertex, reference (-) below the pinna of the ipsilateral ear, and ground in the hind leg (Figure 2).</li>
	<li>Open the ASP software and define the electric pulse stimulation paradigm. We use a charge-balanced biphasic pulse with 50 &#956;s/phase and 10 &#956;s interphase gap presented at 23.3 pulses per second (pps). The electric stimulation is delivered in a monopolar electrode configuration with increasing current levels. A total of 400 responses are averaged at each current level.</li>
	<li>Present the electric pulse trains and record the evoked eABR response continuously via the Tucker Davis Technologies (TDT) headstage, pre-amplifier, and auditory processor.</li>
	<li>Plot and analyze the eABR data via a custom-made Matlab script (Figure 3). The script and an example of a recording are provided in the Supplementary.</li>
</ol>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Hardware</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Low impedance headstage</td>
			<td>TDT, FL, USA</td>
			<td>RA4LI</td>
			<td></td>
		</tr>
		<tr>
			<td>Medusa pre-amplifier</td>
			<td>TDT, FL, USA</td>
			<td>RA4PA</td>
			<td></td>
		</tr>
		<tr>
			<td>RZ6 auditory processor</td>
			<td>TDT, FL, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Animal Stimulator Platform</td>
			<td>ASP, Oticon Medical, Nice, France</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Closed-loop heating pad</td>
			<td>FHC, Inc. ME, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Eye ointment</td>
			<td>Alcon, CH</td>
			<td>Lacrinorm Augengel</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable subdermal needle electrodes</td>
			<td>Horizon, Rochester Electro-Medical Inc.</td>
			<td>S83018-R9, 27G</td>
			<td></td>
		</tr>
		<tr>
			<td>Self-retaining retractor tool (Mini Collibri Retractor)</td>
			<td>Fine Science Tools</td>
			<td>#17000-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Suction wedges</td>
			<td>Agnthos, SE</td>
			<td>#42-886-460</td>
			<td></td>
		</tr>
		<tr>
			<td>Absorbable paper point (Medium)</td>
			<td>WPI, FL, USA</td>
			<td>#504182</td>
			<td></td>
		</tr>
		<tr>
			<td>Intracochlear electrode array</td>
			<td>Bionics Institute, Melbourne, Australia</td>
			<td>4 channel</td>
			<td></td>
		</tr>
		<tr>
			<td>Spongostan Standard</td>
			<td>Ferrosan Medical Devices</td>
			<td>#MS0002</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue glue. Loctite 4161 Superbond</td>
			<td>Henkel</td>
			<td>Part No 19743</td>
			<td></td>
		</tr>
		<tr>
			<td>Animal Stimulator Platform (ASP)</td>
			<td>Oticon Medical, Nice, France</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>BioSigRZ</td>
			<td>TDT, FL, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Matlab</td>
			<td>MathWorks, MA, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ASP software</td>
			<td>Oticon Medical, Nice, France</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

Source: Navntoft, C. A., et al. <a href="https://appjove.unicartagenaproxy.elogim.com/v/58073">Cochlear Implant Surgery and Electrically-evoked Auditory Brainstem Response Recordings in C57BL/6 Mice.</a> J. Vis. Exp. (2019)
This video demonstrates the procedure to implant a cochlear device in a deafened mouse and apply electrical stimuli to record auditory brainstem responses. This procedure enables to understand the basic mechanisms of electrical hearing and can contribute to advancements in cochlear implant technology and auditory neuroscience.

<img alt="Figure 1" src="/files/ftp_upload/22868/22868_Figure1.jpg" /> 
Figure 1: The mouse cochlear implant. (A) The intracochlear electrode array consists of four platinum bands spaced at a 0.4 mm interval with a diameter d: 0 [tip] (d=0.21), 1 (d=0.23), 2 (d=0.25), 3 (d=0.27). The width of each electrode is 0.2 mm. The four platinum/iridium (90/10) parylene insulated wires are shielded in a silicone tube. (B) Magnificatio...

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. ...

Take a deafened mouse with an incision behind the ear.
Position a retractor within the incision to access the bulla, a bony enclosure of the middle ear.
Obtain a cochlear implant containing an intracochlear electrode array with an insulated wire and a ground ball connected to a print board.
Insert the array through the round window at the base of the bulla into the scala tympani, the cochlea&#39;s lower chamber.
Coil the wire inside the bulla and secure it with tissue glue.
Remove the retractor and seal the incision.
Make a small incision in the neck, insert the ground ball, and seal the incision.
Connect the board to the stimulator platform, which delivers electrical stimuli.
Attach the auditory brainstem response, or ABR, electrodes to the vertex, behind the pinna, and on the hind leg.
Apply electrical stimuli and record the evoked electrical ABR response.

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Vídeo: Registro de respostas auditivas do tronco encefálico evocadas eletricamente em um camundongo surdo - Experimento

Auditory Brainstem Response and Outer Hair Cell Whole-cell Patch Clamp Recording in Postnatal Rats

The outer hair cell is one of the two types of sensory hair cells in the mammalian cochlea. They alter their cell length with the receptor potential to amplify the weak vibration of low-level sound signal. The morphology and electrophysiological property of outer hair cells (OHCs) develop in early postnatal ages. The maturation of outer hair cell may contribute to the development of the auditory system. However, the process of OHCs development is not well studied. This is partly because of the difficulty to measure their function by an electrophysiological approach. With the purpose of developing a simple method to address the above issue, here we describe a step-by-step protocol to study the function of OHCs in acutely dissociated cochlea from postnatal rats. With this method, we can evaluate the cochlear response to pure tone stimuli and examine the expression level and function of the motor protein prestin in OHCs. This method can also be used to investigate the inner hair cells (IHCs).

This protocol describes methods to record the auditory brainstem response from postnatal rat pups. To examine the functional development of outer hair cells, the experimental procedure of whole-cell patch clamp recording in isolated outer hair cells is described step-by-step.

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The outer hair cell is one of the two types of sensory hair cells in the mammalian cochlea. They alter their cell length with the receptor potential to ...

JoVE Journal

Neurociência

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.

Preparação e implantação de eletrodos para kindling elétrico de camundongos VGAT-CRE para gerar um modelo para epilepsia do lobo temporal

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 ...

Evaluation of Auditory Brainstem Response in Chicken Hatchlings

The auditory brainstem response (ABR) is an invaluable assay in clinical audiology, non-human animals, and human research. Despite the widespread use of ABRs in measuring auditory neural synchrony and estimating hearing sensitivity in other vertebrate model systems, methods for recording ABRs in the chicken have not been reported in nearly four decades. Chickens provide a robust animal research model because their auditory system is near functional maturation during late embryonic and early hatchling stages. We have demonstrated methods used to elicit one or two-channel ABR recordings using subdermal needle electrode arrays in chicken hatchlings. Regardless of electrode recording configuration (i.e., montage), ABR recordings included 3-4 positive-going peak waveforms within the first 6 ms of a suprathreshold click stimulus. Peak-to-trough waveform amplitudes ranged from 2-11 &#181;V at high-intensity levels, with positive peaks exhibiting expected latency-intensity functions (i.e., increase in latency as a function of decreased intensity). Standardized earphone position was critical for optimal recordings as loose skin can occlude the ear canal, and animal movement can dislodge the stimulus transducer. Peak amplitudes were smaller, and latencies were longer as animal body temperature lowered, supporting the need for maintaining physiological body temperature. For young hatchlings (&#60;3 h post-hatch day 1), thresholds were elevated by ~5 dB, peak latencies increased ~1-2 ms, and peak to trough amplitudes were decreased ~1 &#181;V compared to older hatchlings. This suggests a potential conductive-related issue (i.e., fluid in the middle ear cavity) and should be considered for young hatchlings. Overall, the ABR methods outlined here permit accurate and reproducible recording of in-vivo auditory function in chicken hatchlings that could be applied to different stages of development. Such findings are easily compared to human and mammalian models of hearing loss, aging, or other auditory-related manipulations.

We have used standard auditory brainstem response (ABR) techniques and applied them to hatchling chickens, a precocious avian model for auditory function. The protocol outlines animal preparation and ABR acquisition techniques in detail, with steps that could translate to other avian or rodent models.

Avaliação da Resposta Auditiva do Brainstem em Filhotes de Frango

The auditory brainstem response (ABR) is an invaluable assay in clinical audiology, non-human animals, and human research. Despite the widespread use of ...

Recording Electrically-Evoked Auditory Brainstem Responses in a Deafened Mouse

Transcrição

Recording Electrically-Evoked Auditory Brainstem Responses in a Deafened Mouse