This work was supported by a Canadian Institutes of Health Research (CIHR) grant to A.S. J.K was partially supported by a Universit&eacute; Laval fellowship. A.S. is the recipient of a Canada Research Chair in postnatal neurogenesis.

<ol>
	<li>Kriegstein, A., Alvarez-Buylla, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+glial+nature+of+embryonic+and+adult+neural+stem+cells.">The glial nature of embryonic and adult neural stem cells.</a> Annu. Rev. Neurosci. 32, 149-184 (2009).</li><li>Kaneko, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+neurons+clear+the+path+of+astrocytic+processes+for+their+rapid+migration+in+the+adult+brain.">New neurons clear the path of astrocytic processes for their rapid migration in the adult brain.</a> Neuron. 67, 213-223 (2010).</li><li>Lois, C., Alvarez-Buylla, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-distance+neuronal+migration+in+the+adult+mammalian+brain.">Long-distance neuronal migration in the adult mammalian brain.</a> Science. 264, 1145-1148 (1994).</li><li>Snapyan, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vasculature+guides+migrating+neuronal+precursors+in+the+adult+mammalian+forebrain+via+brain-derived+neurotrophic+factor+signaling.">Vasculature guides migrating neuronal precursors in the adult mammalian forebrain via brain-derived neurotrophic factor signaling.</a> J. Neurosci. 29, 4172-4188 (2009).</li><li>Whitman, M. C., Fan, W., Rela, L., Rodriguez-Gil, D. J., Greer, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+vessels+form+a+migratory+scaffold+in+the+rostral+migratory+stream.">Blood vessels form a migratory scaffold in the rostral migratory stream.</a> J. Comp. Neurol. 516, 94-104 (2009).</li><li>Lledo, P. M., Saghatelyan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrating+new+neurons+into+the+adult+olfactory+bulb:+joining+the+network,+life-death+decisions,+and+the+effects+of+sensory+experience.">Integrating new neurons into the adult olfactory bulb: joining the network, life-death decisions, and the effects of sensory experience.</a> Trends Neurosci. 28, 248-254 (2005).</li><li>Bolteus, A. J., Bordey, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GABA+release+and+uptake+regulate+neuronal+precursor+migration+in+the+postnatal+subventricular+zone.">GABA release and uptake regulate neuronal precursor migration in the postnatal subventricular zone.</a> J. Neurosci. 24, 7623-7631 (2004).</li><li>Martini, F. J., Valdeolmillos, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Actomyosin+contraction+at+the+cell+rear+drives+nuclear+translocation+in+migrating+cortical+interneurons.">Actomyosin contraction at the cell rear drives nuclear translocation in migrating cortical interneurons.</a> J. Neurosci. 30, 8660-8670 (2010).</li><li>Murase, S., Horwitz, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deleted+in+colorectal+carcinoma+and+differentially+expressed+integrins+mediate+the+directional+migration+of+neural+precursors+in+the+rostral+migratory+stream.">Deleted in colorectal carcinoma and differentially expressed integrins mediate the directional migration of neural precursors in the rostral migratory stream.</a> J. Neurosci. 22, 3568-3579 (2002).</li><li>Wilcock, A. C., Swedlow, J. R., Storey, K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitotic+spindle+orientation+distinguishes+stem+cell+and+terminal+modes+of+neuron+production+in+the+early+spinal+cord.">Mitotic spindle orientation distinguishes stem cell and terminal modes of neuron production in the early spinal cord.</a> Development. 134, 1943-1954 (2007).</li><li>Ono, M., Yanagawa, Y., Koyano, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GABAergic+neurons+in+inferior+colliculus+of+the+GAD67-GFP+knock-in+mouse:+electrophysiological+and+morphological+properties.">GABAergic neurons in inferior colliculus of the GAD67-GFP knock-in mouse: electrophysiological and morphological properties.</a> Neurosci. Res. 51, 475-492 (2005).</li><li>Bozoyan, L., Khlghatyan, J., Saghatelyan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Astrocytes+Control+the+Development+of+the+Migration-Promoting+Vasculature+Scaffold+in+the+Postnatal+Brain+via+VEGF+Signaling.">Astrocytes Control the Development of the Migration-Promoting Vasculature Scaffold in the Postnatal Brain via VEGF Signaling.</a> J. Neurosci. 32, 1687-1704 (2012).</li><li>Bovetti, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+vessels+form+a+scaffold+for+neuroblast+migration+in+the+adult+olfactory+bulb.">Blood vessels form a scaffold for neuroblast migration in the adult olfactory bulb.</a> J. Neurosci. 27, 5976-5980 (2007).</li><li>Platel, J. C., Heintz, T., Young, S., Gordon, V., Bordey, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tonic+activation+of+GLUK5+kainate+receptors+decreases+neuroblast+migration+in+whole-mounts+of+the+subventricular+zone.">Tonic activation of GLUK5 kainate receptors decreases neuroblast migration in whole-mounts of the subventricular zone.</a> J. Physiol. 586, 3783-3793 (2008).</li><li>Nam, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+features+of+postnatal+subventricular+zone+cell+motility:+a+two-photon+time-lapse+study.">Dynamic features of postnatal subventricular zone cell motility: a two-photon time-lapse study.</a> J. Comp. Neurol. 505, 190-208 (2007).</li><li>Kim, Y., Comte, I., Szabo, G., Hockberger, P., Szele, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adult+mouse+subventricular+zone+stem+and+progenitor+cells+are+sessile+and+epidermal+growth+factor+receptor+negatively+regulates+neuroblast+migration.">Adult mouse subventricular zone stem and progenitor cells are sessile and epidermal growth factor receptor negatively regulates neuroblast migration.</a> PLoS One. 4, e8122 (2009).</li><li>Bortone, D., Polleux, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=KCC2+expression+promotes+the+termination+of+cortical+interneuron+migration+in+a+voltage-sensitive+calcium-dependent+manner.">KCC2 expression promotes the termination of cortical interneuron migration in a voltage-sensitive calcium-dependent manner.</a> Neuron. 62, 53-71 (2009).</li><li>Comte, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Galectin-3+maintains+cell+motility+from+the+subventricular+zone+to+the+olfactory+bulb.">Galectin-3 maintains cell motility from the subventricular zone to the olfactory bulb.</a> J. Cell Sci. 124, 2438-2447 (2011).</li></ol>

No conflicts of interest declared.

The correct targeting of neuronal precursors to the appropriate brain regions is a fundamental process underlying the proper assembly and function of neural circuitry. The vast majority of cells migrate during embryonic development and in the postnatal brain only in a few regions, such as the OB, dentate gyrus and cerebellum, neuronal displacement still takes place. The mechanisms orchestrating cell migration in the postnatal brain remain, however, poorly understood. Knowledge of the mechanisms and molecular pathways in...

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 <td>Sigma</td>
 <td>S9378</td>
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 <td>Glucose (ACSF)</td>
 <td>EMD</td>
 <td>DX0145-3</td>
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 <td>NaCI</td>
 <td>Sigma</td>
 <td>S9625</td>
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 <td>Sigma</td>
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 <td>MgCI2x6H2O</td>
 <td>Sigma-Aldrich</td>
 <td>M2670</td>
 </tr>
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 <td>NaHCO3</td>
 <td>Sigma</td>
 <td>S5761</td>
 </tr>
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 <td>NaH2PO4xH2O</td>
 <td>EMD</td>
 <td>SX0710-1</td>
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 <td>Sigma-Aldrich</td>
 <td>C3881</td>
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 <td>Dextran TexasRed</td>
 <td>Invitrogen</td>
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 <td>Dextran CascadeBlue</td>
 <td>Invitrogen</td>
 <td>D1976</td>
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 <td>Glucose (40X solution)</td>
 <td>Sigma</td>
 <td>G8769</td>
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 <td>Sodium pyruvat</td>
 <td>Gibco</td>
 <td>11360-070</td>
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 <td>HEPES</td>
 <td>Sigma</td>
 <td>H3375</td>
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 <td>HBSS</td>
 <td>Gibco</td>
 <td>14170-112</td>
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 <td>DNase I</td>
 <td>Sigma</td>
 <td>D-5025</td>
 </tr>
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 <td>Trypsin-EDTA</td>
 <td>Gibco</td>
 <td>25300-054</td>
 </tr>
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 <td>Neurobasal medium</td>
 <td>Gibco</td>
 <td>21103-049</td>
 </tr>
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 <td>BSA</td>
 <td>EMD</td>
 <td>2930</td>
 </tr>
 <tr>
 <td>Pen/Strep</td>
 <td>Life Technologies</td>
 <td>15140-122</td>
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 <td>Ketamine/Xylazine</td>
 <td>CDMV</td>
 <td>5230</td>
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 <td>Pasteur pipette</td>
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 <td>14672-380</td>
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 <td>15 ml conical tube</td>
 <td>Sarstedt</td>
 <td>62.553.205</td>
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 <td>50 ml conical tube</td>
 <td>Sarstedt</td>
 <td>62.547.205</td>
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 <td>Glass capillaries (stereotaxic injection)</td>
 <td>WPI</td>
 <td>4878</td>
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 <td>Paraffin oil</td>
 <td>EMD</td>
 <td>PX0045-3</td>
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 <td>Proviodine</td>
 <td>Rougier</td>
 <td>65655-1370</td>
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 <td>Suture</td>
 <td>Stoelting</td>
 <td>50487</td>
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 <td>Anafen</td>
 <td>CDMV</td>
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 <td>20 cc Syringe</td>
 <td>VWR</td>
 <td>SS-20L2</td>
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 <td>Petri dish</td>
 <td>VWR</td>
 <td>25384-094</td>
 </tr>
 <tr>
 <td>Agar</td>
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 <td>AP-0108</td>
 </tr>
 <tr>
 <td>Glue</td>
 <td>Permabond</td>
 <td>910</td>
 </tr>
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 <td>95% O2/5% CO2</td>
 <td>Linde</td>
 <td>24068835</td>
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 <td>WPI</td>
 <td>501901</td>
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 <td>Nylon mesh</td>
 <td>Warner Instruments</td>
 <td>64-0198</td>
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 <td>Eppendorf</td>
 <td>5702 000.019</td>
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 <td>Sutter Instrument </td>
 <td>P-97</td>
 </tr>
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 <td>Nanoliter injector</td>
 <td>WPI</td>
 <td>B203MC4</td>
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 <td>Stereotaxic injection apparatus</td>
 <td>WPI</td>
 <td>502900</td>
 </tr>
 <tr>
 <td>Micro drill system</td>
 <td>WPI</td>
 <td>501819</td>
 </tr>
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 <td>Vibratome</td>
 <td>Thermo Scientific</td>
 <td>920110</td>
 </tr>
 <tr>
 <td>Wide-field fluorescent microscope</td>
 <td>Olympus</td>
 <td>BX61WIF</td>
 </tr>
 <tr>
 <td>CCD camera</td>
 <td>Photometrics</td>
 <td>CS-HQ2-D</td>
 </tr>
 <tr>
 <td>Ultra-quiet imaging chamber</td>
 <td>Harvard Apparatus </td>
 <td>64-1487</td>
 </tr>
 <tr>
 <td>PH-1 Series 20 heater platform</td>
 <td>Harvard Apparatus </td>
 <td>64-0284</td>
 </tr>
 <tr>
 <td>Heating system</td>
 <td>Warner Instruments </td>
 <td>TC-344B</td>
 </tr>
 <tr>
 <td>40X water immersion objective</td>
 <td>Olympus</td>
 <td>1-UM587</td>
 </tr>
 <tr>
 <td>10X water immersion objective</td>
 <td>Olympus</td>
 <td>1-UM583</td>
 </tr>
 <tr>
 <td>Lambda DG-4</td>
 <td>Sutter Instruments</td>
 <td>DG-4/OF</td>
 </tr>
 <tr>
 <td>MetaMorph software</td>
 <td>Molecular Devices</td>
 <td>40000</td>
 </tr>
 <tr>
 <td>Imaris software</td>
 <td>Bitplane</td>
 <td>BPI-IM70-F1</td>
 </tr>
 </tbody>
</table>

time-lapse imaging of neuroblast migration in acute slices of the adult mouse forebrain

There is a substantial body of evidence indicating that new functional neurons are constitutively generated from an endogenous pool of neural stem cells in restricted areas of the adult mammalian brain. Newborn neuroblasts from the subventricular zone (SVZ) migrate along the rostral migratory stream (RMS) to their final destination in the olfactory bulb (OB)1. In the RMS, neuroblasts migrate tangentially in chains ensheathed by astrocytic processes2,3 using blood vessels as a structural support and a source of molecular factors required for migration4,5. In the OB, neuroblasts detach from the chains and migrate radially into the different bulbar layers where they differentiate into interneurons and integrate into the existing network1, 6.
In this manuscript we describe the procedure for monitoring cell migration in acute slices of the rodent brain. The use of acute slices allows the assessment of cell migration in the microenvironment that closely resembling to in vivo conditions and in brain regions that are difficult to access for in vivo imaging. In addition, it avoids long culturing condition as in the case of organotypic and cell cultures that may eventually alter the migration properties of the cells. Neuronal precursors in acute slices can be visualized using DIC optics or fluorescent proteins. Viral labeling of neuronal precursors in the SVZ, grafting neuroblasts from reporter mice into the SVZ of wild-type mice, and using transgenic mice that express fluorescent protein in neuroblasts are all suitable methods for visualizing neuroblasts and following their migration. The later method, however, does not allow individual cells to be tracked for long periods of time because of the high density of labeled cells. We used a wide-field fluorescent upright microscope equipped with a CCD camera to achieve a relatively rapid acquisition interval (one image every 15 or 30 sec) to reliably identify the stationary and migratory phases. A precise identification of the duration of the stationary and migratory phases is crucial for the unambiguous interpretation of results. We also performed multiple z-step acquisitions to monitor neuroblasts migration in 3D. Wide-field fluorescent imaging has been used extensively to visualize neuronal migration7-10. Here, we describe detailed protocol for labeling neuroblasts, performing real-time video-imaging of neuroblast migration in acute slices of the adult mouse forebrain, and analyzing cell migration. While the described protocol exemplified the migration of neuroblasts in the adult RMS, it can also be used to follow cell migration in embryonic and early postnatal brains.

Watch this Scientific Journal Video about Time-lapse Imaging of Neuroblast Migration in Acute Slices of the Adult Mouse Forebrain at JoVE.com

Time-lapse Imaging of Neuroblast Migration in Acute Slices of the Adult Mouse Forebrain

We describe a protocol for real-time videoimaging of neuronal migration in the mouse forebrain. The migration of virally-labeled or grafted neuronal precursors was recorded in acute live slices using wide-field fluorescent imaging with a relatively rapid acquisition interval to study the different phases of cell migration, including the durations of the stationary and migration phases and the speed of migration.

There is a substantial body of evidence indicating that new functional neurons are constitutively generated from an endogenous pool of neural stem cells ...

time-lapse-imaging-neuroblast-migration-acute-slices-adult-mouse

Research

JoVE Journal

Neuroscience

14.8K Views.  Centre de Recherche Université Laval Robert-Giffard. We describe a protocol for real-time videoimaging of neuronal migration in the mouse forebrain. The migration of virally-labeled or grafted neuronal precursors was recorded in acute live slices using wide-field fluorescent imaging with a relatively rapid acquisition interval to study the different phases of cell migration, including the durations of the stationary and migration phases and the speed of migration.

Video: Time-lapse Imaging of Neuroblast Migration in Acute Slices of the Adult Mouse Forebrain

An Organotypic Slice Assay for High-Resolution Time-Lapse Imaging of Neuronal Migration in the Postnatal Brain

Neurogenesis in the postnatal brain depends on maintenance of three biological events: proliferation of progenitor cells, migration of neuroblasts, as well as differentiation and integration of new neurons into existing neural circuits. For postnatal neurogenesis in the olfactory bulbs, these events are segregated within three anatomically distinct domains: proliferation largely occurs in the subependymal zone (SEZ) of the lateral ventricles, migrating neuroblasts traverse through the rostral migratory stream (RMS), and new neurons differentiate and integrate within the olfactory bulbs (OB). The three domains serve as ideal platforms to study the cellular, molecular, and physiological mechanisms that regulate each of the biological events distinctly. This paper describes an organotypic slice assay optimized for postnatal brain tissue, in which the extracellular conditions closely mimic the in vivo environment for migrating neuroblasts. We show that our assay provides for uniform, oriented, and speedy movement of neuroblasts within the RMS. This assay will be highly suitable for the study of cell autonomous and non-autonomous regulation of neuronal migration by utilizing cross-transplantation approaches from mice on different genetic backgrounds.

This protocol describes an organotypic slice assay optimized for the postnatal brain and high-resolution time-lapse imaging of neuroblast migration in the rostral migratory stream.

Neurogenesis in the postnatal brain depends on maintenance of three biological events: proliferation of progenitor cells, migration of neuroblasts, as ...

Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain

Precise patterns of division, migration and differentiation of neural progenitor cells are crucial for proper brain development and function1,2. To understand the behavior of neural progenitor cells in the complex in vivo environment, time-lapse live imaging of neural progenitor cells in an intact brain is critically required. In this video, we exploit the unique features of zebrafish embryos to visualize the development of forebrain neural progenitor cells in vivo. We use electroporation to genetically and sparsely label individual neural progenitor cells. Briefly, DNA constructs coding for fluorescent markers were injected into the forebrain ventricle of 22 hours post fertilization (hpf) zebrafish embryos and electric pulses were delivered immediately. Six hours later, the electroporated zebrafish embryos were mounted with low melting point agarose in glass bottom culture dishes. Fluorescently labeled neural progenitor cells were then imaged for 36hours with fixed intervals under a confocal microscope using water dipping objective lens. The present method provides a way to gain insights into the in vivo development of forebrain neural progenitor cells and can be applied to other parts of the central nervous system of the zebrafish embryo.

The present video demonstrates a method which takes advantage of the combination of electroporation and confocal microscopy to perform live imaging on individual neural progenitor cells in the developing zebrafish forebrain. In vivo analysis of the development of forebrain neural progenitor cells at a clonal level can be achieved in this way.

Precise patterns of division, migration and differentiation of neural progenitor cells are crucial for proper brain development and function1,2. To ...

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 ...

Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.

The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs ...

Motor Nerve Transection and Time-lapse Imaging of Glial Cell Behaviors in Live Zebrafish

The nervous system is often described as a hard-wired component of the body even though it is a considerably fluid organ system that reacts to external stimuli in a consistent, stereotyped manner, while maintaining incredible flexibility and plasticity. Unlike the central nervous system (CNS), the peripheral nervous system (PNS) is capable of significant repair, but we have only just begun to understand the cellular and molecular mechanisms that govern this phenomenon. Using zebrafish as a model system, we have the unprecedented opportunity to couple regenerative studies with in vivo imaging and genetic manipulation. Peripheral nerves are composed of axons surrounded by layers of glia and connective tissue. Axons are ensheathed by myelinating or non-myelinating Schwann cells, which are in turn wrapped into a fascicle by a cellular sheath called the perineurium. Following an injury, adult peripheral nerves have the remarkable capacity to remove damaged axonal debris and re-innervate targets. To investigate the roles of all peripheral glia in PNS regeneration, we describe here an axon transection assay that uses a commercially available nitrogen-pumped dye laser to axotomize motor nerves in live transgenic zebrafish. We further describe the methods to couple these experiments to time-lapse imaging of injured and control nerves. This experimental paradigm can be used to not only assess the role that glia play in nerve regeneration, but can also be the platform for elucidating the molecular mechanisms that govern nervous system repair.

Although the peripheral nervous system (PNS) is capable of significant repair after injury, little is known about the cellular and molecular mechanisms that govern this phenomenon. Using live, transgenic zebrafish and a reproducible nerve transection assay, we can study dynamic glial cell behaviors during nerve degeneration and regeneration.

The  nervous system is often described as a hard-wired component of the body even  though it is a considerably fluid organ system that reacts to external ...

In vivo Postnatal Electroporation and Time-lapse Imaging of Neuroblast Migration in Mouse Acute Brain Slices

The subventricular zone (SVZ) is one of the main neurogenic niches in the postnatal brain. Here, neural progenitors proliferate and give rise to neuroblasts able to move along the rostral migratory stream (RMS) towards the olfactory bulb (OB). This long-distance migration is required for the subsequent maturation of newborn neurons in the OB, but the molecular mechanisms regulating this process are still unclear. Investigating the signaling pathways controlling neuroblast motility may not only help understand a fundamental step in neurogenesis, but also have therapeutic regenerative potential, given the ability of these neuroblasts to target brain sites affected by injury, stroke, or degeneration.
In this manuscript we describe a detailed protocol for in vivo postnatal electroporation and subsequent time-lapse imaging of neuroblast migration in the mouse RMS. Postnatal electroporation can efficiently transfect SVZ progenitor cells, which in turn generate neuroblasts migrating along the RMS. Using confocal spinning disk time-lapse microscopy on acute brain slice cultures, neuroblast migration can be monitored in an environment closely resembling the in vivo condition. Moreover, neuroblast motility can be tracked and quantitatively analyzed. As an example, we describe how to use in vivo postnatal electroporation of a GFP-expressing plasmid to label and visualize neuroblasts migrating along the RMS. Electroporation of shRNA or CRE recombinase-expressing plasmids in conditional knockout mice employing the LoxP system can also be used to target genes of interest. Pharmacological manipulation of acute brain slice cultures can be performed to investigate the role of different signaling molecules in neuroblast migration. By coupling in vivo electroporation with time-lapse imaging, we hope to understand the molecular mechanisms controlling neuroblast motility and contribute to the development of novel approaches to promote brain repair.

In vivo Postnatal Electroporation and Time-lapse Imaging of Neuroblast Migration in Mouse Acute Brain Slices

Neuroblast migration is a fundamental event in postnatal neurogenesis. We describe a protocol for efficient labeling of neuroblasts by in vivo postnatal electroporation and subsequent visualization of their migration using time-lapse imaging of acute brain slices. We include a description for the quantitative analysis of neuroblast dynamics by video tracking.

The subventricular zone (SVZ) is one of the main neurogenic niches in the postnatal brain. Here, neural progenitors proliferate and give rise to ...

Nucleofection of Rodent Neuroblasts to Study Neuroblast Migration In vitro

The subventricular zone (SVZ) located in the lateral wall of the lateral ventricles plays a fundamental role in adult neurogenesis. In this restricted area of the brain, neural stem cells proliferate and constantly generate neuroblasts that migrate tangentially in chains along the rostral migratory stream (RMS) to reach the olfactory bulb (OB). Once in the OB, neuroblasts switch to radial migration and then differentiate into mature neurons able to incorporate into the preexisting neuronal network. Proper neuroblast migration is a fundamental step in neurogenesis, ensuring the correct functional maturation of newborn neurons. Given the ability of SVZ-derived neuroblasts to target injured areas in the brain, investigating the intracellular mechanisms underlying their motility will not only enhance the understanding of neurogenesis but may also promote the development of neuroregenerative strategies.
This manuscript describes a detailed protocol for the transfection of primary rodent RMS postnatal neuroblasts and the analysis of their motility using a 3D in vitro migration assay recapitulating their mode of migration observed in vivo. Both rat and mouse neuroblasts can be quickly and efficiently transfected via nucleofection with either plasmid DNA, small hairpin (sh)RNA or short interfering (si)RNA oligos targeting genes of interest. To analyze migration, nucleofected cells are reaggregated in &#39;hanging drops&#39; and subsequently embedded in a three-dimensional matrix. Nucleofection per se does not significantly impair the migration of neuroblasts. Pharmacological treatment of nucleofected and reaggregated neuroblasts can also be performed to study the role of signaling pathways involved in neuroblast migration.

Nucleofection of Rodent Neuroblasts to Study Neuroblast Migration In vitro

Neuroblast migration is a crucial step in postnatal neurogenesis. The protocol described here can be used to investigate the role of candidate regulators of neuroblast migration by employing DNA/small hairpin RNA (shRNA) nucleofection and a 3D migration assay with neuroblasts isolated from the rodent postnatal rostral migratory stream.

The subventricular zone (SVZ) located in the lateral wall of the lateral ventricles plays a fundamental role in adult neurogenesis. In this restricted ...

Long-term Time Lapse Imaging of Mouse Cochlear Explants

Here we present a method for long-term time-lapse imaging of live embryonic mouse cochlear explants. The developmental program responsible for building the highly ordered, complex structure of the mammalian cochlea proceeds for around ten days. In order to study changes in gene expression over this period and their response to pharmaceutical or genetic manipulation, long-term imaging is necessary. Previously, live imaging has typically been limited by the viability of explanted tissue in a humidified chamber atop a standard microscope. Difficulty in maintaining optimal conditions for culture growth with regard to humidity and temperature has placed limits on the length of imaging experiments. A microscope integrated into a modified tissue culture incubator provides an excellent environment for long term-live imaging. In this method we demonstrate how to establish embryonic mouse cochlear explants and how to use an incubator microscope to conduct time lapse imaging using both bright field and fluorescent microscopy to examine the behavior of a typical embryonic day (E) 13 cochlear explant and Sox2, a marker of the prosensory cells of the cochlea, over 5 days.

Live imaging of the embryonic mammalian cochlea is challenging because the developmental processes at hand operate on a temporal gradient over ten days. Here we present a method for culturing and then imaging embryonic cochlear explant tissue taken from a fluorescent reporter mouse over five days.

Here we present a method for long-term time-lapse imaging of live embryonic mouse cochlear explants. The developmental program responsible for building ...

In-depth Physiological Analysis of Defined Cell Populations in Acute Tissue Slices of the Mouse Vomeronasal Organ

In most mammals, the vomeronasal organ (VNO) is a chemosensory structure that detects both hetero- and conspecific social cues. Vomeronasal sensory neurons (VSNs) express a specific type of G protein-coupled receptor (GPCR) from at least three different chemoreceptor gene families allowing sensitive and specific detection of chemosensory cues. These families comprise the V1r and V2r gene families as well as the formyl peptide receptor (FPR)-related sequence (Fpr-rs) family of putative chemoreceptor genes. In order to understand the physiology of vomeronasal receptor-ligand interactions and downstream signaling, it is essential to identify the biophysical properties inherent to each specific class of VSNs.
The physiological approach described here allows identification and in-depth analysis of a defined population of sensory neurons using a transgenic mouse line (Fpr-rs3-i-Venus). The use of this protocol, however, is not restricted to this specific line and thus can easily be extended to other genetically modified lines or wild type animals.

Here, we describe a physiological approach that allows identification and in-depth analysis of a defined population of sensory neurons in acute coronal tissue slices of the mouse vomeronasal organ using whole-cell patch-clamp recordings.

In most mammals, the vomeronasal organ (VNO) is a chemosensory structure that detects both hetero- and conspecific social cues. Vomeronasal sensory ...

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 ...