Current and former Rubel lab members.

1. Preparation of Dissecting Area
<ol>
<li>Continuously bubble artificial cerebral spinal fluid (ACSF) with a mixture of 95% O2 / 5% CO2 (pH between 7.2-7.4, osmolarity 295-310 mOsm/l).</li>
<li>While ACSF is bubbling, clean working area with 70% EtOH. Also clean the vibratome and slicing blade. Rinse blade with distilled water (dH2O).</li>
<li>Place clean fluid absorption pad on dissecting area with appropriate dissecting tools.</li>
<li>Glue agar block (40 mg agarose / mL, i.e. 4%, in dH2O) to the stage of a vibratome-slicing chamber*. 
*Tip: prepare agar prior to dissection. Store pre-made agar inside a covered petri dish in the refrigerator. Agarose purchased from EMD Chemicals or Invitrogen.</li>
</ol>
2. Preparation of 6-well Plates with Culture Medium
<ol>
<li>Under a sterile hood, fill 1 well per animal of a 6-well plate with 1 mL of culture medium and incubate at 35&deg;C and 5% CO2.</li>
<li>Prepare as many culture membrane inserts as needed and place them in hood for later use.</li>
</ol>
3. Isolation of Chicken Auditory Brainstem
<ol>
<li>Place egg under a bright light source to determine the air filled space void of the embryo (typically the large side of the egg).</li>
<li>Break open large side of egg exposing membrane sac. Make slice in membrane sac with scalpel and gently remove the head of the chicken embryo.</li>
<li>Rapidly decapitate head with scissors.</li>
<li>Place tip of razor blade slightly posterior to and between the eyes. Make a rostral-to-caudal midline incision through the skull applying only slight pressure*. 
*Tip: pressure applied is dependent on the age of the embryo (i.e., younger = less, older = more)</li>
<li>Gently push aside skin and feathers to expose skull and verify midline cut.</li>
<li>Block rostral portion of skull by slicing with a razor blade. Position blade posterior to eyes and rapidly cut through entire skull and brain tissue*. 
*Tip: strong pressure is required to completely remove rostral section.</li>
<li>Make midline-to-lateral incisions with small scissors in the caudal region of the skull, slightly anterior to visible neck muscles on both sides of the head. Pull away skull and tissue to expose cerebellum and brain.</li>
<li>Gently remove brainstem from skull base by cutting attached tissue with small scissors. Once all tissue is cut, brainstem should move freely away from the skull*. 
*Tip: you may need to flip the skull (brain down) to cut attached tissue.</li>
</ol>
4. 	Preparation of Brainstem for Slicing
<ol>
<li>Once removed from the skull, pin brainstem down through the optic tecta.</li>
<li>Completely remove the cerebellum by gently cutting the peduncles with small scissors, exposing the floor of the fourth ventricle.</li>
<li>Remove any membranous tissue and blood vessel from the surface of the brainstem with tweezers and make lateral cuts through the optic tecta to isolate the brainstem.</li>
<li>Place a small amount of super glue on the vibratome stage in front of the agar block (towards the vibratome blade).</li>
<li>Using tweezers, gently and swiftly lift the brainstem at the spinal cord and place tissue onto the super glue with the rostral side down and dorsal side towards to vibratome blade*. 
*Tip: excess glue should be absorbed with a kim-wipe or filter paper before next step.</li>
<li>Gently pour oxygenated ACSF into the vibratome stage*. 
*Note: this ACSF can be continuously bubbled with O2/CO2. However, bubbling of ACSF in such a small volume of solution results in unwanted movement (and possible damage) to brainstem slices. If performed rapidly, already oxygenated ACSF from the dissection is sufficient.</li>
<li>Vibratome blade should be at a 20-22&deg; angle. Start vibratome (oscillation should be set at maximum amplitude) and move stage up towards the blade so that the top of the tissue is parallel with the blade before slicing.</li>
<li>Quickly move blade towards brainstem tissue. Slow down considerably just prior to blade contact with tissue.</li>
<li>Begin slicing tissue with slowest possible forward motion. Once through the entire coronal section of tissue, gently move slice away from the blade with a brush or a broken glass, fired polished pipette, fit at one end with a rubber bulb.</li>
<li>Lower stage in 300-500 &mu;m steps and slice again. Repeat until anatomical signatures are visible in brainstem tissue. At this time, slice brainstem tissue containing auditory structures at 200-1000 &mu;m thicknesses, depending on the age of tissue and experimental needs.</li>
<li>Carefully maintain usable slices in the order of slicing, i.e., the 1st slice represents the most caudal region of the circuit (low-frequency sound processing) and the last slice represents the most rostral section (high-frequency processing)*. 
*Note: for placement of slices for culture use, go to section 6. For in-vitro physiology storage, see next section.</li>
</ol>
5. Slice Storage for in-vitro Physiology
<ol>
<li>Depending on the age of the chicken embryo and the thickness of the slice, each animal should provide 1 to 6 slices.</li>
<li>Gently place individual slices in chamber using fire polished glass pipette fitted at one end with a rubber bulb. Chamber should be numbered. Place only one slice per well, in order to maintain some tonotopic specificity (e.g., most caudal slice in chamber 1 and the most rostral slice in the last chamber). Chamber should be filled with ACSF and continuously bubbled with a mixture of 95% O2 / 5% CO2 (pH 7.4, osmolarity 295-310 mOsm/l).</li>
<li>Allow slices to equilibrate by placing the chamber into a warm bath (36&deg; C) for approximately 1 hour.</li>
<li>Remove chamber from warm bath and allow to rest at room temperature for approximately &frac12; hour.</li>
<li>After &frac12; hours at room temperature, slices can be transferred from the holding chamber to a ~0.5 mL recording chamber mounted on a microscope for electrophysiological experiments.</li>
<li>Slices can be used for up to ~6 hours after removal from the warm bath.</li>
</ol>
6. 	Preparation of Organotypic Slice Cultures 8
<ol>
<li>Immediately following the slicing procedure (see Section 6) transfer slices with ~500 &mu;L ACSF using a fire polished glass pipette fitted at one end with a rubber bulb to a 48 well plate on ice. One slice per well*. 
*Tip: Slices need to be at least 300 &mu;m and up to 1000 &mu;m thick.</li>
<li>After slices have been collected, transfer the 48-well plate to the hood.</li>
<li>Remove a 6-well plate containing culture medium out of the incubator and transfer it to the hood.</li>
<li>Just prior to placing slices from a single brain onto membranes, place one of the prepared membrane inserts (see Section 2.2) into a well with culture medium. Make sure no air bubbles are present under membrane.</li>
<li>Using a glass pipette, transfer a slice in a drop of ACSF onto the culture membrane and remove excess ACSF with a micropipette. Repeat for remaining slices (max 4 slices per membrane)*. 
*Tip: Make sure slices do not touch each other and place slices centrally on the membrane so that they don't touch the membrane rim.</li>
<li>Repeat for as many brain slices as needed*. 
*Tip: If cultures are manipulated at a later time point, it might be advantageous to limit the amount of membranes to 3 per 6-well plate as to reduce the time the cultures are removed from the incubator.</li>
<li>Change culture medium 3 times a week under a hood: Remove old medium with a vacuum tube with a sterile tip while membrane insert is lifted out of the well with a pair of forceps. Add 1 mL of fresh culture medium in well while membrane insert is lifted out of the well. When all medium is changed, put plate back into the incubator.</li>
</ol>
7. Representative Results:

<img src="/files/ftp_upload/2527/2527fig1.jpg" alt="Figure 1" /> 
Figure 1. Binaural circuitry of the chicken auditory brainstem. (A) Schematic of a coronal section and (B-F) in-vitro slice images of the chicken auditory brainstem. The circuit in (A) shows afferent excitatory inputs from the auditory nerve (AN) to nucleus magnocellularis (NM) and nucleus angularis (NA). NM projects bilateral excitatory inputs to nucleus laminaris (NL) on both sides of the brainstem. An inhibitory input from the superior olivary nucleus (SON) projects to NA, NM and NL. The in-vitro slices in (B-F) are sequential images (200 &mu;m each) going from caudal (B) to rostral (F) of the chicken auditory brainstem, representing the low- to high-frequency regions, respectively. Circuitry is responsible for coding temporal properties of sound used primarily for sound localization. Scale bar in (B) = 500 &mu;m and applies for images in (C-F). Arrows in (D) point to the single cell body layer of NL.

<img src="/files/ftp_upload/2527/2527fig2.jpg" alt="Figure 2" /> 
Figure 2. Cultured neurons develop normal physiologic response properties. Superimposed membrane voltage changes in response to hyperpolarizing and depolarizing current steps from acute (A&amp;C) and cultured tissue at 4 (B) and 7 (D) days in culture (DIC). Note changes in hyperpolarizing voltage "sag", strong reduction in outward current, and single AP firing that develop similarly in the slice culture approach compared to age equivalent acute tissue. Current injections were 200 ms, steps of 50-100 pA. RMPs were between -55 and -60 mV.

<img src="/files/ftp_upload/2527/2527fig3.jpg" alt="Figure 3" /> 
Figure 3. Anatomical structure in culture slices. Left half of the auditory brainstem of an E11 chicken after 7 days in culture (DIC). An antibody against the microtubule-associated protein 2 (MAP2), which occurs in the soma and dendrites, is labeled in green. A cluster of nucleus magnocellularis (NM) neurons and its axons are labeled in red via electroporation of an Alexa dextran dye. Both NM and the NL cell line are visible. Ipsilateral NM axon terminals can be seen projecting to the dorsal NL dendrites (white arrowheads).

<ol>
	<li>Howard, M. A., Burger, R. M., Rubel, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+developmental+switch+to+GABAergic+inhibition+dependent+on+increases+in+Kv1-type+K++currents.">A developmental switch to GABAergic inhibition dependent on increases in Kv1-type K+ currents.</a> J Neurosci. 27, 2112-2123 (2007).</li><li>Kuba, H., Koyano, K., Ohmori, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+membrane+conductance+improves+coincidence+detection+in+the+nucleus+laminaris+of+the+chicken.">Development of membrane conductance improves coincidence detection in the nucleus laminaris of the chicken.</a> J Physiol. 540, 529-542 (2002).</li><li>Gao, H., Lu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+development+of+intrinsic+and+synaptic+properties+of+chicken+nucleus+laminaris+neurons.">Early development of intrinsic and synaptic properties of chicken nucleus laminaris neurons.</a> Neuroscience. 153, 131-143 (2008).</li><li>Sanchez, J. T., Wang, Y., Rubel, E. W., Barria, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+glutamatergic+synaptic+transmission+in+binaural+auditory+neurons.">Development of glutamatergic synaptic transmission in binaural auditory neurons.</a> J Neurophysiol. 104, 1774-1789 (2010).</li><li>Jackson, H., Hackett, J. T., Rubel, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organization+and+development+of+brain+stem+auditory+nuclei+in+the+chick:+ontogeny+of+postsynaptic+responses.">Organization and development of brain stem auditory nuclei in the chick: ontogeny of postsynaptic responses.</a> J Comp Neurol. 210, 80-86 (1982).</li><li>Rubel, E. W., Parks, T. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organization+and+development+of+brain+stem+auditory+nuclei+of+the+chicken:+tonotopic+organization+of+n.+magnocellularis+and+n.+laminaris.">Organization and development of brain stem auditory nuclei of the chicken: tonotopic organization of n. magnocellularis and n. laminaris.</a> J Comp Neurol. 164, 411-433 (1975).</li><li>Rubel, E. W., Smith, D. J., Miller, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organization+and+development+of+brain+stem+auditory+nuclei+of+the+chicken:+ontogeny+of+n.+magnocellularis+and+n.+laminaris.">Organization and development of brain stem auditory nuclei of the chicken: ontogeny of n. magnocellularis and n. laminaris.</a> J Comp Neurol. 166, 469-489 (1976).</li><li>Stoppini, L., Buchs, P. A., Muller, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+for+organotypic+cultures+of+nervous+tissue.">A simple method for organotypic cultures of nervous tissue.</a> J Neurosci Methods. 37, 173-182 (1991).</li><li>Reyes, A. D., Rubel, E. W., Spain, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Membrane+properties+underlying+the+firing+of+neurons+in+the+avian+cochlear+nucleus.">Membrane properties underlying the firing of neurons in the avian cochlear nucleus.</a> J Neurosci. 14, 5352-5364 (1994).</li><li>Monsivais, P., Rubel, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accommodation+enhances+depolarizing+inhibition+in+central+neurons.">Accommodation enhances depolarizing inhibition in central neurons.</a> J Neurosci. 21, 7823-7830 (2001).</li><li>Lu, T., Trussell, L. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+elimination+of+endbulb+synapses+in+the+chick+cochlear+nucleus.">Development and elimination of endbulb synapses in the chick cochlear nucleus.</a> J Neurosci. 27, 808-8017 (2007).</li><li>Kuba, H., Yamada, R., Fukui, I., Ohmori, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tonotopic+specialization+of+auditory+coincidence+detection+in+nucleus+laminaris+of+the+chick.">Tonotopic specialization of auditory coincidence detection in nucleus laminaris of the chick.</a> J Neurosci. 25, 1924-1934 (2005).</li><li>Trussell, L. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+mechanisms+for+preservation+of+timing+in+central+auditory+pathways.">Cellular mechanisms for preservation of timing in central auditory pathways.</a> Curr Opin Neurobiol. 7, 487-492 (1997).</li><li>Trussell, L. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synaptic+mechanisms+for+coding+timing+in+auditory+neurons.">Synaptic mechanisms for coding timing in auditory neurons.</a> Annu Rev Physiol. 61, 477-496 (1999).</li><li>Sorensen, S. A., Rubel, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+level+and+integrity+of+synaptic+input+regulates+dendrite+structure.">The level and integrity of synaptic input regulates dendrite structure.</a> J Neurosci. 26, 1539-1550 (2006).</li></ol>

No conflicts of interest declared.

For several decades, the acute slice preparation of the chicken brainstem has been used to study auditory processing 9, 10. This approach has provided a tremendous amount of in-vitro physiological data on binaural processing from both developmental and mature states 4, 11, 12. Much is known about this highly specialized circuit and the role each nucleus plays in the temporal processing of sound 13, 14. In fact, short-term experimental manipulations and their effects on the struct...

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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Chicken ACSF</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>NaCl</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>M-11624</td>
<td>130 mM</td>
</tr>
<tr>
<td>NaHCO3</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>M-10576</td>
<td>26 mM</td>
</tr>
<tr>
<td>KCl</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P-9333</td>
<td>3 mM</td>
</tr>
<tr>
<td>NaH2PO4</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>S-8282</td>
<td>1.25 mM</td>
</tr>
<tr>
<td>Glucose</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>G-7528</td>
<td>10 mM</td>
</tr>
<tr>
<td>MgCl2</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>M33-500</td>
<td>1 mM</td>
</tr>
<tr>
<td>CaCl2</td>
<td>&nbsp;</td>
<td>Acros Organics</td>
<td>423525000</td>
<td>2 mM</td>
</tr>
<tr>
<td>Chicken culture medium (store at 4&deg;C)</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>advanced minimum essential medium (with NEAA, sodium pyruvate at 110 mg/l, without L-glutamate)</td>
<td>&nbsp;</td>
<td>Gibco Invitrogen</td>
<td>12492-013</td>
<td>48.00%</td>
</tr>
<tr>
<td>Earl's balanced salt solution</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>E-2888</td>
<td>24.00%</td>
</tr>
<tr>
<td>L-glutamine (200 mM)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>G-7513</td>
<td>1.00%</td>
</tr>
<tr>
<td>Glucose solution (200 g/l, sterile filtered)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>G-7528</td>
<td>2.75%</td>
</tr>
<tr>
<td>horse serum (heat inactivated, sterile filtered)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>H-1138</td>
<td>24.00%</td>
</tr>
<tr>
<td>Penicillin-streptomycin*</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P-0781</td>
<td>1.00 ml 
* = Add to 100 ml culture medium if needed to prevent contamination</td>
</tr>
<tr>
<td>Specific equipment</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Millicell-CM cell culture inserts</td>
<td>PICMORG50</td>
<td>Millipore</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>6-well plate</td>
<td>6 Well Cell Culture Cluster</td>
<td>Corning Incorporated</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Incubator</td>
<td>Forma Scientific CO2 Water Jacketed Incubator</td>
<td>Forma Scientific</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

preparation and culture of chicken auditory brainstem slices

The chicken auditory brainstem is a well-established model system that has been widely used to study the anatomy and physiology of auditory processing at discreet periods of development 1-4 as well as mechanisms for temporal coding in the central nervous system 5-7.
Here we present a method to prepare chicken auditory brainstem slices that can be used for acute experimental procedures or to culture organotypic slices for long-term experimental manipulations.
The chicken auditory brainstem is composed of nucleus angularis, magnocellularis, laminaris and superior olive. These nuclei are responsible for binaural sound processing and single coronal slice preparations preserve the entire circuitry. Ultimately, organotypic slice cultures can provide the opportunity to manipulate several developmental parameters such as synaptic activity, expression of pre and postsynaptic components, expression of aspects controlling excitability and differential gene expression
This approach can be used to broaden general knowledge about neural circuit development, refinement and maturation.

Watch this Scientific Journal Video about Preparation and Culture of Chicken Auditory Brainstem Slices at JoVE.com

Preparation and Culture of Chicken Auditory Brainstem Slices

The chicken auditory brainstem is comprised of nuclei responsible for binaural sound processing. A single coronal slice preparation maintains the entire circuitry while the cultured approach provides a unique preparation to study the development of neuronal structure and auditory function at the molecular, cellular and network levels.

The chicken auditory brainstem is a well-established model system that has been widely used to study the anatomy and physiology of auditory processing at ...

preparation-and-culture-of-chicken-auditory-brainstem-slices

Research

JoVE Journal

Neuroscience

11.0K Görüntüleme.  University of Washington. Tavuk işitsel beyin sapı Binoral ses işleme için sorumlu çekirdekleri oluşur. Kültürlü bir yaklaşım, nöron yapısı ve işitsel fonksiyonu, moleküler, hücresel ve ağ seviyelerinde gelişimini incelemek için eşsiz bir hazırlık sağlarken tek bir koronal dilim hazırlık tüm devre tutar.

Video: Preparation and Culture of Chicken Auditory Brainstem Slices

Preparation of Oligomeric &beta;-amyloid1-42 and Induction of Synaptic Plasticity Impairment on Hippocampal Slices

Impairment of synaptic connections is likely to underlie the subtle amnesic changes occurring at the early stages of Alzheimer s Disease (AD). &beta;-amyloid (A&beta;), a peptide produced in high amounts in AD, is known to reduce Long-Term Potentiation (LTP), a cellular correlate of learning and memory. Indeed, LTP impairment caused by A&beta; is a useful experimental paradigm for studying synaptic dysfunctions in AD models and for screening drugs capable of mitigating or reverting such synaptic impairments. Studies have shown that A&beta; produces the LTP disruption preferentially via its oligomeric form. Here we provide a detailed protocol for impairing LTP by perfusion of oligomerized synthetic A&beta;1-42 peptide onto acute hippocampal slices. In this video, we outline a step-by-step procedure for the preparation of oligomeric A&beta;1-42. Then, we follow an individual experiment in which LTP is reduced in hippocampal slices exposed to oligomerized A&beta;1-42 compared to slices in a control experiment where no A&beta;1-42 exposure had occurred.

Preparation of Oligomeric &amp;#946;-amyloid1-42 and Induction of Synaptic Plasticity Impairment on Hippocampal Slices

One feature of Alzheimer's Disease is the elevation of A&beta;1-42 peptide. Here we provide a protocol for preparing synthetic A&beta;1-42 oligomers, which impairs hippocampal Long-Term Potentiation, a cellular correlate of memory. This procedure is useful for investigating mechanisms of A&beta;-induced pathology and drug screening.

Impairment of synaptic connections is likely to underlie the subtle amnesic changes occurring at the early stages of Alzheimer s Disease (AD). ...

Preparation of Acute Subventricular Zone Slices for Calcium Imaging

The subventricular zone (SVZ) is one of the two neurogenic zones in the postnatal brain. The SVZ contains densely packed cells, including neural progenitor cells with astrocytic features (called SVZ astrocytes), neuroblasts, and intermediate progenitor cells. Neuroblasts born in the SVZ tangentially migrate a great distance to the olfactory bulb, where they differentiate into interneurons. Intercellular signaling through adhesion molecules and diffusible signals play important roles in controlling neurogenesis. Many of these signals trigger intercellular calcium activity that transmits information inside and between cells. Calcium activity is thus reflective of the activity of extracellular signals and is an optimal way to understand functional intercellular signaling among SVZ cells.
Calcium activity has been studied in many other regions and cell types, including mature astrocytes and neurons. However, the traditional method to load cells with calcium indicator dye (i.e. bath loading) was not efficient at loading all SVZ cell types. Indeed, the cellular density in the SVZ precludes dye diffusion inside the tissue. In addition, preparing sagittal slices will better preserve the three-dimensional arrangement of SVZ cells, particularly the stream of neuroblast migration on the rostral-caudal axis.
Here, we describe methods to prepare sagittal sections containing the SVZ, the loading of SVZ cells with calcium indicator dye, and the acquisition of calcium activity with time-lapse movies. We used Fluo-4 AM dye for loading SVZ astrocytes using pressure application inside the tissue. Calcium activity was recorded using a scanning confocal microscope allowing a precise resolution for distinguishing individual cells. Our approach is applicable to other neurogenic zones including the adult hippocampal subgranular zone and embryonic neurogenic zones. In addition, other types of dyes can be applied using the described method.

A method to load subventricular zone (SVZ) cells with calcium indicator dyes for recording calcium activity is described. The postnatal SVZ contains tightly packed cells including neural progenitor cells and neuroblasts. Rather than using bath loading we injected the dye by pressure inside the tissue allowing better dye diffusion.

The subventricular zone (SVZ) is one of the two neurogenic zones in the postnatal brain. The SVZ contains densely packed cells, including neural ...

Chicken Embryo Spinal Cord Slice Culture Protocol

Slice cultures can facilitate the manipulation of embryo development both pharmacologically and through gene manipulations. In this reduced system, potential lethal side effects due to systemic drug applications can be overcome. However, culture conditions must ensure that normal development proceeds within the reduced environment of the slice. We have focused on the development of the spinal cord, particularly that of spinal motor neurons. We systematically varied culture conditions of chicken embryo slices from the point at which most spinal motor neurons had been born. We assayed the number and type of motor neurons that survived during the culture period and the position of those motor neurons compared to that in vivo. We found that serum type and neurotrophic factors were required during the culture period and were able to keep motor neurons alive for at least 24 hr and allow those motor neurons to migrate to appropriate positions in the spinal cord. We present these culture conditions and the methodology of preparing the embryo slice cultures using eviscerated chicken embryos embedded in agarose and sliced using a vibratome.

Slice cultures facilitate the manipulation of embryo development by gene and pharmacological perturbations. However, culture conditions must ensure that normal development can proceed within the reduced environment of the slice. We illustrate a protocol that facilitates normal spinal cord development to proceed for at least 24 hr.

Slice cultures can facilitate the manipulation of  embryo development both pharmacologically and through gene manipulations. In  this reduced system, ...

Improved Preparation and Preservation of Hippocampal Mouse Slices for a Very Stable and Reproducible Recording of Long-term Potentiation

Long-term potentiation (LTP) is a type of synaptic plasticity characterized by an increase in synaptic strength and believed to be involved in memory encoding. LTP elicited in the CA1 region of acute hippocampal slices has been extensively studied. However the molecular mechanisms underlying the maintenance phase of this phenomenon are still poorly understood. This could be partly due to the various experimental conditions used by different laboratories. Indeed, the maintenance phase of LTP is strongly dependent on external parameters like oxygenation, temperature and humidity. It is also dependent on internal parameters like orientation of the slicing plane and slice viability after dissection.
The optimization of all these parameters enables the induction of a very reproducible and very stable long-term potentiation. This methodology offers the possibility to further explore the molecular mechanisms involved in the stable increase in synaptic strength in hippocampal slices. It also highlights the importance of experimental conditions in in vitro investigation of neurophysiological phenomena.

This paper presents a complete methodology to prepare and preserve in vitro acute hippocampal slices from adult mice. This protocol allows the recording of very stable long-lasting long-term potentiation (LTP) for more than 8 hours with a success rate of 95%.

Long-term potentiation (LTP) is a type of synaptic plasticity characterized by an increase in synaptic strength and believed to be involved in memory ...

Optogenetic Stimulation of the Auditory Nerve

Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted deaf subjects1-6. Nonetheless, sound coding with current CIs has poor frequency and intensity resolution due to broad current spread from each electrode contact activating a large number of SGNs along the tonotopic axis of the cochlea7-9. Optical stimulation is proposed as an alternative to electrical stimulation that promises spatially more confined activation of SGNs and, hence, higher frequency resolution of coding. In recent years, direct infrared illumination of&#160;the cochlea has been used to evoke responses in the auditory nerve10. Nevertheless it requires higher energies than electrical stimulation10,11 and uncertainty remains as to the underlying mechanism12. Here we describe a method based on optogenetics to stimulate SGNs with low intensity blue light, using transgenic mice with neuronal expression of channelrhodopsin 2 (ChR2)13 or virus-mediated expression of the ChR2-variant CatCh14. We used micro-light emitting diodes (&#181;LEDs) and fiber-coupled lasers to stimulate ChR2-expressing SGNs through a small artificial opening (cochleostomy) or the round window. We assayed the responses by scalp recordings of light-evoked potentials (optogenetic auditory brainstem response: oABR) or by microelectrode recordings from the auditory pathway and compared them with acoustic and electrical stimulation.

Cochlear implants (CIs) enable hearing by direct electrical stimulation of the auditory nerve. However, poor frequency and intensity resolution limits the quality of hearing with CIs. Here we describe optogenetic stimulation of the auditory nerve in mice as an alternative strategy for auditory research and developing future CIs.

Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted ...

The Preparation of Oblique Spinal Cord Slices for Ventral Root Stimulation

Electrophysiological recordings from spinal cord slices have proven to be a valuable technique to investigate a wide range of questions, from cellular to network properties. We show how to prepare viable oblique slices of the spinal cord of young mice (P2 - P11). In this preparation, the motoneurons retain&#160;their axons coming out from the ventral roots of the&#160;spinal cord. Stimulation of these axons elicits back-propagating action potentials invading the motoneuron&#160;somas and exciting the motoneuron&#160;collaterals within the spinal cord. Recording of antidromic action potentials is an immediate, definitive and elegant way to characterize motoneuron identity, which surpasses&#160;other identification methods. Furthermore, stimulating the motoneuron collaterals is a simple and reliable way to excite the collateral targets of the motoneurons within the spinal cord, such as other motoneurons or Renshaw cells. In this protocol, we present antidromic recordings from the motoneuron somas as well as Renshaw cell excitation, resulting from ventral root stimulation.

We show how to prepare oblique slices of the spinal cord in young mice. This preparation allows for the stimulation of the ventral roots.

Electrophysiological recordings from spinal cord slices have proven to be a valuable technique to investigate a wide range of questions, from cellular to ...

Preparation of Horizontal Slices of Adult Mouse Retina for Electrophysiological Studies

Vertical slice preparations are well established to study circuitry and signal transmission in the adult mammalian retina. The plane of sectioning in these preparations is perpendicular to the retinal surface, making it ideal for the study of radially oriented neurons like photoreceptors and bipolar cells. However, the large dendritic arbors of horizontal cells, wide-field amacrine cells, and ganglion cells are mostly truncated, leaving markedly reduced synaptic activity in these cells. Whereas ganglion cells and displaced amacrine cells can be studied in a whole-mounted preparation of the retina, horizontal cells and amacrine cells located in the inner nuclear layer are only poorly accessible for electrodes in whole retina tissue.
To achieve maximum accessibility and synaptic integrity, we developed a horizontal slice preparation of the mouse retina, and studied signal transmission at the synapse between photoreceptors and horizontal cells. Horizontal sectioning allows&#160;(1) easy and unambiguous visual identification of horizontal cell bodies for electrode targeting, and (2) preservation of the extended horizontal cell dendritic fields, as a prerequisite for intact and functional cone synaptic input to horizontal cell dendrites.
Horizontal cells from horizontal slices exhibited tonic synaptic activity in the dark, and they responded to brief flashes of light with a reduction of inward current and diminished synaptic activity. Immunocytochemical evidence indicates that almost all cones within the dendritic field of a horizontal cell establish synapses with its peripheral dendrites. The horizontal slice preparation is therefore well suited to study the physiological properties of horizontally extended retinal neurons as well as sensory signal transmission and integration across selected synapses.

We developed a horizontal slice preparation of the adult mammalian retina with the plane of sectioning parallel to the retinal surface. Dendritic fields of nonradially oriented retinal neurons were not truncated, allowing the study of signal processing with patch-clamp and imaging techniques.

Vertical slice preparations are well established to study circuitry and signal transmission in the adult mammalian retina. The plane of sectioning in ...

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.

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 ...

Cochlear Implant Surgery and Electrically-evoked Auditory Brainstem Response Recordings in C57BL/6 Mice

Cochlear implants (CIs) are neuroprosthetic devices that can provide a sense of hearing to deaf people. However, a CI cannot restore all aspects of hearing. Improvement of the implant technology is needed if CI users are to perceive music and perform in more natural environments, such as hearing out a voice with competing talkers, reflections, and other sounds. Such improvement requires experimental animals to better understand the mechanisms of electric stimulation in the cochlea and its responses in the whole auditory system. The mouse is an increasingly attractive model due to the many genetic models available. However, the limited use of this species as a CI model is mainly due to the difficulty of implanting small electrode arrays. More details about the surgical procedure are therefore of great interest to expand the use of mice in CI research.
In this report, we describe in detail the protocol for acute deafening and cochlear implantation of an electrode array in the C57BL/6 mouse strain. We demonstrate the functional efficacy of this procedure with electrically-evoked auditory brainstem response (eABR) and show examples of facial nerve stimulation. Finally, we also discuss the importance of including a deafening procedure when using a normally hearing animal. This mouse model provides a powerful opportunity to study genetic and neurobiological mechanisms that would be of relevance for CI users.

Animal models of cochlear implants can advance knowledge of the technological bases of treating permanent sensorineural hearing loss with electrical stimulation. This study presents a surgical protocol for acute deafening and cochlear implantation of an electrode array in mice as well as the functional assessment with auditory brainstem response.

Cochlear implants (CIs) are neuroprosthetic devices that can provide a sense of hearing to deaf people. However, a CI cannot restore all aspects of ...

Preparation of Rhythmically-active In Vitro Neonatal Rodent Brainstem-spinal Cord and Thin Slice

Mammalian inspiratory rhythm is generated from a neuronal network in a region of the medulla called the preB&#246;tzinger complex (pBC), which produces a signal driving the rhythmic contraction of inspiratory muscles. Rhythmic neural activity generated in the pBC and carried to other neuronal pools to drive the musculature of breathing may be studied using various approaches, including en bloc nerve recordings and transverse slice recordings. However, previously published methods have not extensively described the brainstem-spinal cord dissection process in a transparent and reproducible manner for future studies. Here, we present a comprehensive overview of a method used to reproducibly cut rhythmically-active brainstem slices containing the necessary and sufficient neuronal circuitry for generating and transmitting inspiratory drive. This work builds upon previous brainstem-spinal cord electrophysiology protocols to enhance the likelihood of reliably obtaining viable and rhythmically-active slices for recording neuronal output from the pBC, hypoglossal premotor neurons (XII pMN), and hypoglossal motor neurons (XII MN). The work presented expands upon previous published methods by providing detailed, step-by-step illustrations of the dissection, from whole rat pup, to in vitro slice containing the XII rootlets.

This protocol both visually communicates the brainstem-spinal cord preparation and clarifies the preparation of brainstem transverse slices in a comprehensive step-by-step manner. It was designed to increase reproducibility and enhance the likelihood of obtaining viable, long lasting, rhythmically-active slices for recording neural output from the respiratory regions of the brainstem.

Mammalian inspiratory rhythm is generated from a neuronal network in a region of the medulla called the preB&#246;tzinger complex (pBC), which produces a ...