ברצוננו להודות שון וילן לסיוע בהצלת ריאנטים VSV רקומביננטי, וDidem גוז וריאן Chrenek לסיוע טכני. עבודה זו נתמכה על ידי HHMI (CLC), ו# NS068012-01 (KTB).

<ol>
	<li>Wickersham, I. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monosynaptic+restriction+of+transsynaptic+tracing+from+single,+genetically+targeted+neurons.">Monosynaptic restriction of transsynaptic tracing from single, genetically targeted neurons.</a> Neuron. 53, 639-647 (2007).</li><li>Marshel, J. H., Mori, T., Nielsen, K. J., Callaway, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+single+neuronal+networks+for+gene+expression+and+cell+labeling+in+vivo.">Targeting single neuronal networks for gene expression and cell labeling in vivo.</a> Neuron. 67, 562-574 (2010).</li><li>Wall, N. R., Wickersham, I. R., Cetin, A., De La Parra, M., Callaway, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monosynaptic+circuit+tracing+in+vivo+through+Cre-dependent+targeting+and+complementation+of+modified+rabies+virus.">Monosynaptic circuit tracing in vivo through Cre-dependent targeting and complementation of modified rabies virus.</a> Proc. Natl. Acad. Sci. U.S.A. 107, 21848-21853 (2010).</li><li>Wickersham, I. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monosynaptic+restriction+of+transsynaptic+tracing+from+single,+genetically+targeted+neurons.">Monosynaptic restriction of transsynaptic tracing from single, genetically targeted neurons.</a> Neuron. 53, 639-647 (2007).</li><li>Yonehara, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatially+asymmetric+reorganization+of+inhibition+establishes+a+motion-sensitive+circuit.">Spatially asymmetric reorganization of inhibition establishes a motion-sensitive circuit.</a> Nature. 469, 407-410 (2011).</li><li>Stepien, A. E., Tripodi, M., Arber, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monosynaptic+rabies+virus+reveals+premotor+network+organization+and+synaptic+specificity+of+cholinergic+partition+cells.">Monosynaptic rabies virus reveals premotor network organization and synaptic specificity of cholinergic partition cells.</a> Neuron. 68, 456-472 (2010).</li><li>Beier, K. T., Samson, M. E. S., Matsuda, T., Cepko, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conditional+expression+of+the+TVA+receptor+allows+clonal+analysis+of+descendents+from+Cre-expressing+progenitor+cells.">Conditional expression of the TVA receptor allows clonal analysis of descendents from Cre-expressing progenitor cells.</a> Dev. Biol. 353, 309-320 (2011).</li><li>Seidler, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Cre-loxP-based+mouse+model+for+conditional+somatic+gene+expression+and+knockdown+in+vivo+by+using+avian+retroviral+vectors.">A Cre-loxP-based mouse model for conditional somatic gene expression and knockdown in vivo by using avian retroviral vectors.</a> Proc. Natl. Acad. Sci. U.S.A. 105, 10137-10142 (2008).</li><li>Beier, K. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anterograde+or+retrograde+transsynaptic+labeling+of+CNS+neurons+with+vesicular+stomatitis+virus+vectors.">Anterograde or retrograde transsynaptic labeling of CNS neurons with vesicular stomatitis virus vectors.</a> Proc. Natl. Acad. Sci. U.S.A. 108, 15414-15419 (2011).</li><li>Whelan, S. P., Ball, L. A., Barr, J. N., Wertz, G. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+recovery+of+infectious+vesicular+stomatitis+virus+entirely+from+cDNA+clones.">Efficient recovery of infectious vesicular stomatitis virus entirely from cDNA clones.</a> Proc. Natl. Acad. Sci. U.S.A. 92, 8388-8392 (1995).</li><li>Fuerst, T. R., Niles, E. G., Studier, F. W., Moss, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eukaryotic+Transient-Expression+System+Based+on+Recombinant+Vaccinia+Virus+That+Synthesizes+Bacteriophage+T7+RNA+Polymerase.">Eukaryotic Transient-Expression System Based on Recombinant Vaccinia Virus That Synthesizes Bacteriophage T7 RNA Polymerase.</a> PNAS. 83, 8122-8126 (1986).</li><li>Young, J. A., Bates, P., Varmus, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+a+chicken+gene+that+confers+susceptibility+to+infection+by+subgroup+A+avian+leukosis+and+sarcoma+viruses.">Isolation of a chicken gene that confers susceptibility to infection by subgroup A avian leukosis and sarcoma viruses.</a> J. Virol. 67, 1811-1816 (1993).</li><li>Madisen, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+robust+and+high-throughput+Cre+reporting+and+characterization+system+for+the+whole+mouse+brain.">A robust and high-throughput Cre reporting and characterization system for the whole mouse brain.</a> Nat Neurosci. 13, 133-140 (2010).</li><li>Franklin, K., Paxinos, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Mouse Brain in Stereotaxic Coordinates. , (1997).</li><li>van den Pol, A. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viral+strategies+for+studying+the+brain,+including+a+replication-restricted+self-amplifying+delta-G+vesicular+stomatis+virus+that+rapidly+expresses+transgenes+in+brain+and+can+generate+a+multicolor+golgi-like+expression.">Viral strategies for studying the brain, including a replication-restricted self-amplifying delta-G vesicular stomatis virus that rapidly expresses transgenes in brain and can generate a multicolor golgi-like expression.</a> J. Comp. Neurol. 516, 456-481 (2009).</li></ol>

אין ניגודי האינטרסים הכריזו.

שימוש בוירוסים כדי ללמוד מעגלים עצביים הוא שיטת תפוקה גבוהה יחסית של ניתוח נוירונים מקושרים. עם זאת, שהניב גם virions RABV VSV ואינו טריוויאלי. למרות שהפרוטוקול מפורט לעיל להצלת וירוס מcDNA מסופק, זה עדיין אירוע הסתברות נמוכה. הרמות של כל אחד מN, P, ופלסמידים L צריכות להיות מותאמ...

<table border="1">
	<tbody>
		<tr>
			<td>Reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Tissue Culture</td>
		</tr>
		<tr>
			<td>Baby Hamster Kidney (BSRT7) cells</td>
			<td>available upon request</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>vaccinia (vTF7-3)</td>
			<td>available upon request</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>pN, pP, pl plasmids</td>
			<td>available upon request</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Calcium Chloride</td>
			<td>Sigma</td>
			<td>C1016</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Magnesium Chloride</td>
			<td>Sigma</td>
			<td>M8266</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>HEK 293T cells</td>
			<td>Open Biosystems</td>
			<td>HCL4517</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>60 mm TC-Treated Culture Dish</td>
			<td>Corning</td>
			<td>430166</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>75 cm2 Rectangular Canted Neck Cell Culture Flask with Vent Cap</td>
			<td>Corning</td>
			<td>430641</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Media : DMEM (Dulbecco's Modified Eagle Medium)</td>
			<td>Invitrogen</td>
			<td>12491-015</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>1 M HEPES pH 7.4</td>
			<td>Gibo</td>
			<td>15630-080</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>FBS: Fetal Bovine Serum</td>
			<td>Gibco</td>
			<td>10437-028</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>PKS</td>
			<td>Invitrogen</td>
			<td>15140-163</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Lipofectamine 2,000 Transfection Reagent</td>
			<td>Invitrogen</td>
			<td>11668-019</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Syringe: 5 ml Luer-Lock syringe</td>
			<td>Sigma</td>
			<td>Z248010-1PAK</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Syringe Filters</td>
			<td>Nalgene</td>
			<td>190-2520</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>PEI: High Potency Linear PEI</td>
			<td>Polysciences</td>
			<td>23966</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Viral Centrifugation</td>
		</tr>
		<tr>
			<td>Corning 150 ml Tube Top Vacuum Filter System, 0.45 &mu;m Pore</td>
			<td>Corning</td>
			<td>430314</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Thinwall, Ultra-Clear, 38.5 ml, 25 x 89 mm ultracentrifuge tubes</td>
			<td>Beckman-Coulter</td>
			<td>344058</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ultracentrifuge</td>
			<td>Beckman-Coulter</td>
			<td>optima XL-80K</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>SW28 Ultracentrifuge rotor</td>
			<td>Beckman-Coulter</td>
			<td>342207</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Mouse Injection</td>
		</tr>
		<tr>
			<td>Capillary micropipets</td>
			<td>Drummond</td>
			<td>5-000-2005</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Stereotax</td>
			<td>Narishige</td>
			<td>SR-5M</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Micromanipulator</td>
			<td>Narishige</td>
			<td>SM-15</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ump injector</td>
			<td>World Precision Instruments</td>
			<td>Sys-Micro4</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Four channel microcontroller</td>
			<td>World Precision Instruments</td>
			<td>UMP3</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>M.TXB Bench Motor with C.EMX-1 Dial Control, 115 Volt</td>
			<td>Foredom</td>
			<td>M.TXB-EM</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>H.10 Handpiece, Quick Change</td>
			<td>Foredom</td>
			<td>H.10</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Step Drill, 0.5 mm</td>
			<td>Foredom</td>
			<td>A-58005P</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Microelectrode holder</td>
			<td>World Precision Instruments</td>
			<td>MEH2S</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ketamine</td>
			<td>Henry Schein</td>
			<td>995-2949</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Henry Schein</td>
			<td>4015809TV</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Buprenorphine</td>
			<td>Henry Schein</td>
			<td>1118217</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>1 ml syringe</td>
			<td>Becton-Dickinson</td>
			<td>309628</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>30 gauge injection needle</td>
			<td>Becton-Dickinson</td>
			<td>305106</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Protective Ophthalmic Ointment</td>
			<td>Doctors Foster and Smith</td>
			<td>9N-014748</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Sigma</td>
			<td>493511</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Iodine</td>
			<td>Sigma</td>
			<td>PVP1</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Surgery and Dissection tools</td>
		</tr>
		<tr>
			<td>Scissors</td>
			<td>Fine Science Tools</td>
			<td>91402-12</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Standard Forceps</td>
			<td>Fine Science Tools</td>
			<td>11000-12</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Fine Forceps</td>
			<td>Fine Science Tools</td>
			<td>11255-20</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Vannas spring scissors</td>
			<td>Fine Science Tools</td>
			<td>15000-00</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Scalpel handle</td>
			<td>Fine Science Tools</td>
			<td>10003-12</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Scalpel blades</td>
			<td>Fine Science Tools</td>
			<td>10015-00</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sutures</td>
			<td>Robbins Instruments</td>
			<td>20.SK640</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Dissection and antibody staining</td>
		</tr>
		<tr>
			<td>paraformaldehyde</td>
			<td>Sigma</td>
			<td>P6148</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline</td>
			<td>Sigma</td>
			<td>P4417</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma</td>
			<td>T9284</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Donkey Serum</td>
			<td>Jackson Immunoresearch</td>
			<td>017-000-121</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Antibodies</td>
		</tr>
		<tr>
			<td>Antibodies</td>
			<td>millipore</td>
			<td>AB144P</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Anti-gfp</td>
			<td>Abcam</td>
			<td>ab13970</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Donkey anti-chicken Dylight 488</td>
			<td>Jackson immunoresearch</td>
			<td>703-545-155</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Donkey anti-chicken Alexa Fluor 647</td>
			<td>Jackson immunoresearch</td>
			<td>705-605-147</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Invitrogen</td>
			<td>D1306</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Tissue mounting</td>
		</tr>
		<tr>
			<td>Superfrost plus microscope slides</td>
			<td>Fisher</td>
			<td>12-550-100</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Cover glass 22 x 22, 0 thickness</td>
			<td>Electron Microscopy Sciences</td>
			<td>72198-10</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Silicone elastomer</td>
			<td>Rogers Corp</td>
			<td>HT-6220</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Clear nail polish</td>
			<td>Electron Microscopy Sciences</td>
			<td>72180</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Prolong Gold antifade reagent</td>
			<td>Invitrogen</td>
			<td>P36930</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

viral tracing of genetically defined neural circuitry

שיטות קלסיות לחקר מעגלים עצביים הן תפוקה נמוכה למדי. וירוסי Transsynaptic, במיוחד pseudorabies (PRV) ונגיף כלבת (RABV), ולאחרונה שלפוחי וירוס stomatitis (VSV), ללימוד מעגלים, יותר ויותר פופולריים. שיטות תפוקה גבוהות אלה להשתמש וירוסים שמשדרים בין הנוירונים בשני כיווני אנטרוגרדית או מדרדר. לאחרונה, RABV שונה לאיתור מדרדר monosynaptic פותח. (איור 1 א). בשיטה זו, גליקופרוטאין הגן (G) נמחק מהגנום הנגיפי, והצטייד במצרכים רק בנוירונים ממוקדים. הספציפיות זיהום מושגת על ידי החלפת G chimeric, מורכב מהתחום התאי של ASLV-גליקופרוטאין ותחום cytoplasmic של RABV-G (/ RG), לנורמלי 1 RABV-G. G chimeric זה במיוחד מדביק תאים המבטאים את הקולטן TVA 1. גן קידוד TVA יכול היה דelivered על ידי שיטות שונות 2-8. בעקבות זיהום RABV-G של נוירון TVA מבטא, RABV יכול לשדר לנוירונים אחרים, הקשורות בsynaptically כיוון מדרדר ידי הטבע של G שלו אשר היה השותף נמסר-עם קולט TVA. טכניקה זו מתייגת מספר רב יחסי של תשומות (5-10%) 2 על סוג תא מוגדר, מתן דגימה של כל תשומות על סוג תא תנע מוגדר. אנחנו שונים לאחרונה בטכניקה זו כדי להשתמש VSV כ9 נותב transsynaptic. VSV יש מספר יתרונות, כולל המהירות של ביטוי גנים. כאן אנחנו פירוט מערכת איתור נגיפית חדשה באמצעות VSV השימושי לחקור microcircuitry עם רזולוציה מוגברת. בעוד אסטרטגיות המקוריות שפורסמו על ידי Wickersham et al. 4 ו אייר et al. תיוג 9 היתר של כל הנוירונים שמשליכים על נגוע, תחילה TVA-להביע תאים, כאן VSV תוכנן לשידור רק לטלביזיהתאים המבטאים-(האיור 1B). וירוס pseudotyped הראשון עם RABV-G להתיר זיהום של מורד הנוירונים של נוירונים המבטאים TVA-. לאחר הדבקת האוכלוסייה ראשונה זה של תאים, הווירוס יכול להדביק תאים שוחרר TVA מבטא בלבד. בגלל ההתפשטות הנגיפית transsynaptic מוגבלת לתאים המבטאים TVA-, נוכחות של העדר קישוריות מסוגי תאים מוגדרים ניתן לחקור ברזולוציה גבוהה. תרשים זרימה ניסיונית של ניסויים אלה מוצג באיור 2. כאן אנו מציגים מודל מעגל, שכיוון של-הסלקטיביות ברשתית העכבר. אנו בודקים את הקישוריות של תאי התפרצות כוכבי amacrine (צקים) לתאי הגנגליון ברשתית (RGCs).

Watch this Scientific Journal Video about Viral Tracing of Genetically Defined Neural Circuitry at JoVE.com

Viral Tracing of Genetically Defined Neural Circuitry

שיטה של ​​התחקות נוירונים הקשורים synaptically מתוארת. אנו משתמשים סגוליים TVA של תא במעלה זרם כדי לבחון אם אוכלוסיית תא של עניין מקבלת קלט סינפטי מסוגי תאים מוגדרים מבחינה גנטית.

איתור נגיפי של מעגלים עצביים מוגדרים גנטי

Classical methods for studying neuronal circuits are fairly low throughput. Transsynaptic viruses, particularly the pseudorabies (PRV) and rabies virus ...

viral-tracing-of-genetically-defined-neural-circuitry

Research

JoVE Journal

Neuroscience

18.3K Views.  Harvard Medical School. שיטה של ​​התחקות נוירונים הקשורים synaptically מתוארת. אנו משתמשים סגוליים TVA של תא במעלה זרם כדי לבחון אם אוכלוסיית תא של עניין מקבלת קלט סינפטי מסוגי תאים מוגדרים מבחינה גנטית.

Video: Viral Tracing of Genetically Defined Neural Circuitry

Physiological, Morphological and Neurochemical Characterization of Neurons Modulated by Movement

The role of individual neurons and their function in neuronal circuits is fundamental to understanding the neuronal mechanisms of sensory and motor functions. Most investigations of sensorimotor mechanisms rely on either examination of neurons while an animal is static1,2 or record extracellular neuronal activity during a movement.3,4 While these studies have provided the fundamental background for sensorimotor function, they either do not evaluate functional information which occurs during a movement or are limited in their ability to fully characterize the anatomy, physiology and neurochemical phenotype of the neuron. A technique is shown here which allows extensive characterization of individual neurons during an in vivo movement. This technique can be used not only to study primary afferent neurons but also to characterize motoneurons and sensorimotor interneurons. Initially the response of a single neuron is recorded using electrophysiological methods during various movements of the mandible followed by determination of the receptive field for the neuron. A neuronal tracer is then intracellularly injected into the neuron and the brain is processed so that the neuron can be visualized with light, electron or confocal microscopy (Fig. 1). The detailed morphology of the characterized neuron is then reconstructed so that neuronal morphology can be correlated with the physiological response of the neuron (Figs. 2,3). In this communication important key details and tips for successful implementation of this technique are provided. Valuable additional information can be determined for the neuron under study by combining this method with other techniques. Retrograde neuronal labeling can be used to determine neurons with which the labeled neuron synapses; thus allowing detailed determination of neuronal circuitry. Immunocytochemistry can be combined with this method to examine neurotransmitters within the labeled neuron and to determine the chemical phenotypes of neurons with which the labeled neuron synapses. The labeled neuron can also be processed for electron microscopy to determine the ultrastructural features and microcircuitry of the labeled neuron. Overall this technique is a powerful method to thoroughly characterize neurons during in vivo movement thus allowing substantial insight into the role of the neuron in sensorimotor function.

A technique is described to quantify the in vivo physiological response of mammalian neurons during movement and correlate the physiology of the neuron with neuronal morphology, neurochemical phenotype and synaptic microcircuitry.

אפיון פיזיולוגיים, מורפולוגי והעצבית של נוירונים מווסתת על ידי תנועת

The role of individual neurons and their function in neuronal circuits is fundamental to understanding the neuronal mechanisms of sensory and motor ...

Detection of Microregional Hypoxia in Mouse Cerebral Cortex by Two-photon Imaging of Endogenous NADH Fluorescence

The brain's ability to function at high levels of metabolic demand depends on continuous oxygen supply through blood flow and tissue oxygen diffusion. Here we present a visualized experimental and methodological protocol to directly visualize microregional tissue hypoxia and to infer perivascular oxygen gradients in the mouse cortex. It is based on the non-linear relationship between nicotinamide adenine dinucleotide (NADH) endogenous fluorescence intensity and oxygen partial pressure in the tissue, where observed tissue NADH fluorescence abruptly increases at tissue oxygen levels below 10 mmHg1. We use two-photon excitation at 740 nm which allows for concurrent excitation of intrinsic NADH tissue fluorescence and blood plasma contrasted with Texas-Red dextran. The advantages of this method over existing approaches include the following: it takes advantage of an intrinsic tissue signal and can be performed using standard two-photon in vivo imaging equipment; it permits continuous monitoring in the whole field of view with a depth resolution of ~50 &mu;m. We demonstrate that brain tissue areas furthest from cerebral blood vessels correspond to vulnerable watershed areas which are the first to become functionally hypoxic following a decline in vascular oxygen supply. This method allows one to image microregional cortical oxygenation and is therefore useful for examining the role of inadequate or restricted tissue oxygen supply in neurovascular diseases and stroke.

Here we describe a method to directly visualize microregional tissue hypoxia in the mouse cortex in vivo. It is based on concurrent two-photon imaging of nicotinamide adenine dinucleotide (NADH) and the cortical microcirculation. This method is useful for high resolution analysis of tissue oxygen supply.

זיהוי של היפוקסיה Microregional בקליפת עכבר מוחין על ידי הדמיה של שני הפוטונים אנדוגני NADH Fluorescence

The brain's ability to function at high levels of metabolic demand depends on continuous oxygen supply through blood flow and tissue oxygen diffusion. ...

Reproducible Mouse Sciatic Nerve Crush and Subsequent Assessment of Regeneration by Whole Mount Muscle Analysis

Regeneration in the peripheral nervous system (PNS) is widely studied both for its relevance to human disease and to understand the robust regenerative response mounted by PNS neurons thereby possibly illuminating the failures of CNS regeneration1. Sciatic nerve crush (axonotmesis) is one of the most common models of peripheral nerve injury in rodents2. Crushing interrupts all axons but Schwann cell basal laminae are preserved so that regeneration is optimal3,4. This allows the investigator to study precisely the ability of a growing axon to interact with both the Schwann cell and basal laminae4. Rats have generally been the preferred animal models for experimental nerve crush. They are widely available and their lesioned sciatic nerve provides a reasonable approximation of human nerve lesions5,4. Though smaller in size than rat nerve, the mouse nerve has many similar qualities. Most importantly though, mouse models are increasingly valuable because of the wide availability of transgenic lines now allows for a detailed dissection of the individual molecules critical for nerve regeneration6, 7. Prior investigators have used multiple methods to produce a nerve crush or injury including simple angled forceps, chilled forceps, hemostatic forceps, vascular clamps, and investigator-designed clamps8,9,10,11,12. Investigators have also used various methods of marking the injury site including suture, carbon particles and fluorescent beads13,14,1. We describe our method to obtain a reproducibly complete sciatic nerve crush with accurate and persistent marking of the crush-site using a fine hemostatic forceps and subsequent carbon crush-site marking. As part of our description of the sciatic nerve crush procedure we have also included a relatively simple method of muscle whole mount we use to subsequently quantify regeneration.

In this report we describe a method to crush mouse sciatic nerve. This method uses readily available hemostatic forceps and easily and reproducibly produces complete sciatic nerve crush. In addition, we describe a method to prepare muscle whole mounts suitable for analysis of nerve regeneration after sciatic nerve crush.

עכבר לשחזור Sciatic עצב קראש והערכה לאחר ההתחדשות של ניתוח הר שלם שריר

Regeneration in the peripheral nervous system (PNS) is widely studied both for its relevance to human disease and to understand the robust regenerative ...

Expansion of Embryonic and Adult Neural Stem Cells by In Utero Electroporation or Viral Stereotaxic Injection

Somatic stem cells can divide to generate additional stem cells (expansion) or more differentiated cell types (differentiation), which is fundamental for tissue formation during embryonic development and tissue homeostasis during adulthood 1. Currently, great efforts are invested towards controlling the switch of somatic stem cells from expansion to differentiation because this is thought to be fundamental for developing novel strategies for regenerative medicine 1,2. However, a major challenge in the study and use of somatic stem cell is that their expansion has been proven very difficult to control.
Here we describe a system that allows the control of neural stem/progenitor cell (altogether referred to as NSC) expansion in the mouse embryonic cortex or the adult hippocampus by manipulating the expression of the cdk4/cyclinD1 complex, a major regulator of the G1 phase of the cell cycle and somatic stem cell differentiation 3,4. Specifically, two different approaches are described by which the cdk4/cyclinD1 complex is overexpressed in NSC in vivo. By the first approach, overexpression of the cell cycle regulators is obtained by injecting plasmids encoding for cdk4/cyclinD1 in the lumen of the mouse telencephalon followed by in utero electroporation to deliver them to NSC of the lateral cortex, thus, triggering episomal expression of the transgenes 5-8. By the second approach, highly concentrated HIV-derived viruses are stereotaxically injected in the dentate gyrus of the adult mouse hippocampus, thus, triggering constitutive expression of the cell cycle regulators after integration of the viral construct in the genome of infected cells 9. Both approaches, whose basic principles were already described by other video protocols 10-14, were here optimized to i) reduce tissue damage, ii) target wide portions of very specific brain regions, iii) obtain high numbers of manipulated cells within each region, and iv) trigger high expression levels of the transgenes within each cell. Transient overexpression of the transgenes using the two approaches is obtained by different means i.e. by natural dilution of the electroporated plasmids due to cell division or tamoxifen administration in Cre-expressing NSC infected with viruses carrying cdk4/cyclinD1 flanked by loxP sites, respectively 9,15.
These methods provide a very powerful platform to acutely and tissue-specifically manipulate the expression of any gene in the mouse brain. In particular, by manipulating the expression of the cdk4/cyclinD1 complex, our system allows the temporal control of NSC expansion and their switch to differentiation, thus, ultimately increasing the number of neurons generated in the mammalian brain. Our approach may be critically important for basic research and using somatic stem cells for therapy of the mammalian central nervous system while providing a better understanding of i) stem cell contribution to tissue formation during development, ii) tissue homeostasis during adulthood, iii) the role of adult neurogenesis in cognitive functions, and perhaps, iv) better using somatic stem cells in models of neurodegenerative diseases.

Expansion of Embryonic and Adult Neural Stem Cells by In Utero Electroporation or Viral Stereotaxic Injection

Controlling the expansion of somatic stem cells is a major factor hampering their study and use in therapy. Here we describe a system to temporally control neural stem cells expansion during development and adulthood, which can be used to increase the number of neurons generated in the mouse brain.

התרחבות של תאי גזע עצביים עובריים ומבוגרים על ידי<em&gt; ברחם</em&gt; Electroporation או הזרקת Stereotaxic ויראלי

Somatic stem cells can divide to generate additional stem cells (expansion) or more differentiated cell types (differentiation), which is fundamental for ...

Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve

The embryonic chick is a widely used model for the study of peripheral and central ganglion cell projections. In the auditory system, selective labeling of auditory axons within the VIIIth cranial nerve would enhance the study of central auditory circuit development. This approach is challenging because multiple sensory organs of the inner ear contribute to the VIIIth nerve 1. Moreover, markers that reliably distinguish auditory versus vestibular groups of axons within the avian VIIIth nerve have yet to be identified. Auditory and vestibular pathways cannot be distinguished functionally in early embryos, as sensory-evoked responses are not present before the circuits are formed. Centrally projecting VIIIth nerve axons have been traced in some studies, but auditory axon labeling was accompanied by labeling from other VIIIth nerve components 2,3. Here, we describe a method for anterograde tracing from the acoustic ganglion to selectively label auditory axons within the developing VIIIth nerve. First, after partial dissection of the anterior cephalic region of an 8-day chick embryo immersed in oxygenated artificial cerebrospinal fluid, the cochlear duct is identified by anatomical landmarks. Next, a fine pulled glass micropipette is positioned to inject a small amount of rhodamine dextran amine into the duct and adjacent deep region where the acoustic ganglion cells are located. Within thirty minutes following the injection, auditory axons are traced centrally into the hindbrain and can later be visualized following histologic preparation. This method provides a useful tool for developmental studies of peripheral to central auditory circuit formation.

Here we describe a microdissection technique followed by fluorescent dye injection into the acoustic ganglion of early chick embryos for selective tracing of auditory axon fibers in the nerve and hindbrain.

איתור סלקטיבי של סיבי עצב שמיעה בVestibulocochlear העוברי העופות

The embryonic chick is a widely used model for the study of peripheral and central ganglion cell projections. In the auditory system, selective labeling ...

Modeling Astrocytoma Pathogenesis In Vitro and In Vivo Using Cortical Astrocytes or Neural Stem Cells from Conditional, Genetically Engineered Mice

Current astrocytoma models are limited in their ability to define the roles of oncogenic mutations in specific brain cell types during disease pathogenesis and their utility for preclinical drug development. In order to design a better model system for these applications, phenotypically wild-type cortical astrocytes and neural stem cells (NSC) from conditional, genetically engineered mice (GEM) that harbor various combinations of floxed oncogenic alleles were harvested and grown in culture. Genetic recombination was induced in vitro using adenoviral Cre-mediated recombination, resulting in expression of mutated oncogenes and deletion of tumor suppressor genes. The phenotypic consequences of these mutations were defined by measuring proliferation, transformation, and drug response in vitro. Orthotopic allograft models, whereby transformed cells are stereotactically injected into the brains of immune-competent, syngeneic littermates, were developed to define the role of oncogenic mutations and cell type on tumorigenesis in vivo. Unlike most established human glioblastoma cell line xenografts, injection of transformed GEM-derived cortical astrocytes into the brains of immune-competent littermates produced astrocytomas, including the most aggressive subtype, glioblastoma, that recapitulated the histopathological hallmarks of human astrocytomas, including diffuse invasion of normal brain parenchyma. Bioluminescence imaging of orthotopic allografts from transformed astrocytes engineered to express luciferase was utilized to monitor in vivo tumor growth over time. Thus, astrocytoma models using astrocytes and NSC harvested from GEM with conditional oncogenic alleles provide an integrated system to study the genetics and cell biology of astrocytoma pathogenesis in vitro and in vivo and may be useful in preclinical drug development for these devastating diseases.

Modeling Astrocytoma Pathogenesis In Vitro and In Vivo Using Cortical Astrocytes or Neural Stem Cells from Conditional, Genetically Engineered Mice

Phenotypically wild-type astrocytes and neural stem cells harvested from mice engineered with floxed, conditional oncogenic alleles and transformed via viral Cre-mediated recombination can be used to model astrocytoma pathogenesis in vitro and in vivo by orthotopic injection of transformed cells into brains of syngeneic, immune-competent littermates.

דוגמנות אסטרוציטומה פתוגנזה<em&gt; במבחנה</em&gt; ו<em&gt; בVivo</em&gt; שימוש בקליפת מוח האסטרוציטים או בתאי גזע עצביים מעכברים מותנים, מהונדסים גנטי

Current astrocytoma models are limited in their ability to define the roles of oncogenic mutations in specific brain cell types during disease ...

A Lateralized Odor Learning Model in Neonatal Rats for Dissecting Neural Circuitry Underpinning Memory Formation

Rat pups during a critical postnatal period (&#8804; 10 days) readily form a preference for an odor that is associated with stimuli mimicking maternal care. Such a preference memory can last from hours, to days, even life-long, depending on training parameters. Early odor preference learning provides us with a model in which the critical changes for a natural form of learning occur in the olfactory circuitry. An additional feature that makes it a powerful tool for the analysis of memory processes is that early odor preference learning can be lateralized via single naris occlusion within the critical period. This is due to the lack of mature anterior commissural connections of the olfactory hemispheres at this early age. This work outlines behavioral protocols for lateralized odor learning using nose plugs. Acute, reversible naris occlusion minimizes tissue and neuronal damages associated with long-term occlusion and more aggressive methods such as cauterization. The lateralized odor learning model permits within-animal comparison, therefore greatly reducing variance compared to between-animal designs. This method has been used successfully to probe the circuit changes in the olfactory system produced by training. Future directions include exploring molecular underpinnings of odor memory using this lateralized learning model; and correlating physiological change with memory strength and durations.

This protocol introduces lateralized early odor preference learning in rats using acute single naris occlusion. Lateralized learning permits the examination of behavioral outcomes and underpinning biological mechanisms within the same animals, reducing variance induced by between-animal designs. This protocol can be used to investigate molecular mechanisms underpinning early odor learning.

מודל הלמידה Lateralized ריח חולדות ילודים לביתור גיבוש עצבי מעגל בבסיס זיכרון

Rat pups during a critical postnatal period (&#8804; 10 days) readily form a preference for an odor that is associated with stimuli mimicking maternal ...

Conditional Genetic Transsynaptic Tracing in the Embryonic Mouse Brain

Anatomical path tracing is of pivotal importance to decipher the relationship between brain and behavior. Unraveling the formation of neural circuits during embryonic maturation of the brain however is technically challenging because most transsynaptic tracing methods developed to date depend on stereotaxic tracer injection. To overcome this problem, we developed a binary genetic strategy for conditional genetic transsynaptic tracing in the mouse brain. Towards this end we generated two complementary knock-in mouse strains to selectively express the bidirectional transsynaptic tracer barley lectin (BL) and the retrograde transsynaptic tracer Tetanus Toxin fragment C from the ROSA26 locus after Cre-mediated recombination. Cell-specific tracer production in these mice is genetically encoded and does not depend on mechanical tracer injection. Therefore our experimental approach is suitable to study neural circuit formation in the embryonic murine brain. Furthermore, because tracer transfer across synapses depends on synaptic activity, these mouse strains can be used to analyze the communication between genetically defined neuronal populations during brain development at a single cell resolution. Here we provide a detailed protocol for transsynaptic tracing in mouse embryos using the novel recombinant ROSA26 alleles. We have utilized this experimental technique in order to delineate the neural circuitry underlying maturation of the reproductive axis in the developing female mouse brain.

Capitalizing on a binary genetic strategy we provide a detailed protocol for neural circuit tracing in mice that express complementary transsynaptic tracers after Cre-mediated recombination. Because cell-specific tracer production is genetically encoded, our experimental approach is suitable to study the formation and maturation of neural circuitry during murine embryonic brain development at a single cell resolution.

מותנה הגנטי Transsynaptic איתור במוח העכבר עוברי

Anatomical path tracing is of pivotal importance to decipher the relationship between brain and behavior. Unraveling the formation of neural circuits ...

Laser-guided Neuronal Tracing In Brain Explants

We present a technique which combines an in vitro tracer injection protocol, which uses a series of electrical and pressure pulses to increase dye uptake through electroporation in brain explants with targeted laser illumination and matching filter goggles during the procedure. The described technique of in vitro electroporation by itself yields relatively good visual control for targetting certain areas of the brain. By combining it with laser excitation of fluorescent genetic markers and their read-out through band-passing filter goggles, which can pick up the emissions of the genetically labeled cells/nuclei and the fluorescent tracing dye, a researcher can substantially increase the accuracy of injections by finding the area of interest and controlling for the dye-spread/uptake in the injection area much more efficiently. In addition, the laser illumination technique allows to study the functionality of a given neurocircuit by providing information about the type of neurons projecting to a certain area in cases where the GFP expression is linked to the type of transmitter expressed by a subpopulation of neurons.

We describe a technique to label neurons and their processes via anterograde or retrograde tracer injections into brain nuclei using an in vitro preparation. We modified an existing method of in vitro tracer electroporation by taking advantage of fluorescently labeled mouse mutants and basic optical equipment in order to increase labeling accuracy.

Explants מוח מונחי לייזר עצבי איתור ב

We present a technique which combines an in vitro tracer injection protocol, which uses a series of electrical and pressure pulses to increase dye uptake ...

Retrograde Neuroanatomical Tracing of Phrenic Motor Neurons in Mice

Phrenic motor neurons are cervical motor neurons originating from C3 to C6 levels in most mammalian species. Axonal projections converge into phrenic nerves innervating the respiratory diaphragm. In spinal cord slices, phrenic motor neurons cannot be identified from other motor neurons on morphological or biochemical criteria. We provide the description of procedures for visualizing phrenic motor neuron cell bodies in mice, following intrapleural injections of cholera toxin subunit beta (CTB) conjugated to a fluorophore. This fluorescent neuroanatomical tracer has the ability to be caught up at the diaphragm neuromuscular junction, be carried retrogradely along the phrenic axons and reach the phrenic cell bodies. Two methodological approaches of intrapleural CTB delivery are compared: transdiaphragmatic versus transthoracic injections. Both approaches are successful and result in similar number of CTB-labeled phrenic motor neurons. In conclusion, these techniques can be applied to visualize or quantify the phrenic motor neurons in various experimental studies such as those focused on the diaphragm-phrenic circuitry.

Here, we describe a protocol for identifying phrenic motor neurons in mice after intrapleural delivery of fluorophore conjugated cholera toxin subunit beta. Two techniques are compared to inject the pleural cavity: transdiaphragmatic versus transthoracic approaches.

עקיבה Neuroanatomical רטרוגרדית של הסרעפת מוטורי לגלוקוז בעכברים

Phrenic motor neurons are cervical motor neurons originating from C3 to C6 levels in most mammalian species. Axonal projections converge into phrenic ...