Ringraziamo anche Gabriel Hand per lettura critica.

Tutti gli esperimenti sono stati eseguiti secondo le linee guida stabilite dalle commissioni sul benessere degli animali dell'Università di Osaka e il Giappone Neuroscience Society.
1. organotipiche cocultures del talamo e corteccia cerebrale
Nota: Per la procedura dettagliata, vedere l'originale pubblicazioni7,8,13. Tutte le procedure devono essere eseguite in condizioni sterili. Ratti Sprague-Dawley (deviazione standard) sono utilizzati per colture neuronali.
<ol><li>
Preparazione dei reagenti Nota: Volumi dei seguenti reagenti sono per il cervello di un ratto.<ol>
<li>
Preparare 10 x modificate N2 supplemento 13: insulina (50 μg/mL), progesterone (200 nM), idrocortisone (200 nM), selenito di sodio (300 nM), transferrina (1 mg/mL), putrescina (1 mM), glucosio (60 mg/mL)</li>
		<li>
Terreno di coltura contenente siero preparare (10 mL): 85% DMEM/F12, supplemento del 10% x 10 per volta N2, 5% siero bovino fetale (FBS)</li>
		<li>
Mezzo di coltura privo di siero preparare (20 mL): 90% DMEM/F12, supplemento del 10% x 10 per volta N2</li>
		<li>Preparare soluzione collagene coda di ratto (0,5 mL). In breve, prendere fibre tender da una coda di topo in condizioni sterili e incubare in soluzione di acido acetico durante la notte. Dopo la centrifugazione, raccogliere il surnatante (pochi mg/mL) e conservare in un frigorifero13.</li>
	</ol>
</li>
	<li>
Preparazione di piatti di cultura
	<ol>
<li>Collocare un inserto di membrana in una capsula di Petri da 35 mm.</li>
		<li>Aggiungere 40-50 μL di soluzione di collagene di ratto coda alla membrana e diffondere la soluzione di collagene intorno al centro.</li>
		<li>La membrana completamente in un banco pulito asciugare all'aria.</li>
		<li>Mettere 1,5-2 mL di terreno di coltura contenente siero nel piatto, in modo che la membrana è impregnata con il mezzo.</li>
		<li>Posizionare la piastra di coltura in un incubatore (37 ° C, aria umidificata 95% e 5% CO2) prima di placcatura.</li>
	</ol>
</li>
	<li>
Preparazione di fette corticali
	<ol>
<li>Sterilizzare tutti gli strumenti chirurgici con etanolo al 70% per 10 minuti o più.</li>
		<li>Sezionare l'intero cervello rapidamente da un giorno postnatale (P) 2 ratto sotto anestesia ghiacciata (immerso in cubetti di ghiaccio per pochi minuti).</li>
		<li>Posto il cervello in un 100mm di Petri contenente 100 mL di freddo Hanks soluzione salina equilibrata.</li>
		<li>Rimuovere la materia di pia dal cervello con una pinzetta e tagliare fette corticali (300-400 μm di spessore) dalla corteccia visiva e somatosensoriale con microsurgical forbici (per dettagli, vedere la Figura 1). Nota: Lo spessore delle fette corticali è circa dalla scala di griglie sotto un microscopio binoculare. Nota: In alternativa, fette corticali possono essere fatta con una vibratome in condizioni sterili.</li>
		<li>Trasferire alcune fette corticali sul modulo di membrana con una pipetta di plastica monouso.</li>
		<li>Regolare le posizioni delle fette vicino al centro dell'inserto cultura con una pipetta di Pasteur lucidati a fuoco (per dettagli, Vedi8,13) e rimuovere l'eccesso del prodotto dall'inserto. Nota: Regolare il livello del mezzo leggermente sotto la superficie delle fette di modo che le fette possano ricevere un approvvigionamento sufficiente di gas sia medio. Questo è fondamentale per la vitalità cellulare.</li>
		<li>Mantenere le fette nel terreno di coltura contenente siero a 37 ° C in un ambiente di umidificata 95% aria e 5% CO2e cultura da solo per un giorno prima di un blocco thalamic è preso e messo accanto ad essa.</li>
	</ol>
</li>
	<li>
Preparazione di blocchi thalamic
	<ol>
<li>Sterilizzare tutti gli strumenti chirurgici con etanolo al 70% per 10 minuti o più.</li>
		<li>Anestetizzare un ratto incinto (giorno 15) tramite l'iniezione intraperitoneale di pentobarbital (50 mg/kg) contenenti anestetico.</li>
		<li>Sezionare ogni embrione da corni uterini e inserire gli embrioni in un 100mm di Petri contenente 100 mL di soluzione salina bilanciata di freddo Hanks'.</li>
		<li>Sotto un microscopio binoculare, rimuovere il cervello da ogni embrione e tagliare i blocchi thalamic che contengono prevalentemente il nucleo genicolato laterale e complesso (circa 0,5 mm x 3) ventrobasale7 utilizzando forbici microsurgical (Vedi Figura 1).</li>
	</ol>
</li>
	<li>
Cultura e mantenere organotipiche cocultures
	<ol>
<li>Utilizzando una pipetta Pasteur, posizionare il blocco thalamic accanto la superficie ventricolare della fetta corticale che è stato messo sulla membrana filtrante.</li>
		<li>Mantenere i cocultures nel terreno di coltura contenente siero a 37 ° C in un ambiente di aria umidificata 95% e 5% CO2.</li>
		<li>Cambio di metà del mezzo con il mezzo di coltura privo di siero dopo due giorni di cultura. Da allora in poi, scambiare il mezzo ogni 2-3 giorni. Nota: Il livello del mezzo dovrebbe essere controllato dopo il cambio medio, quanto è importante per la sopravvivenza delle cellule.</li>
	</ol>
</li>
</ol>2. elettroporazione
Tutte le procedure devono essere eseguite in condizioni sterili.
Nota: Eseguire l'elettroporazione un giorno dopo la preparazione dei blocchi thalamic per evitare il distacco dei blocchi.
<ol><li>
Plasmidi
	<ol>
<li>Fare una miscela di plasmidi come segue: pCAGGS-DsRed 2 μg/μL; pCAG-SYP-EGFP 3.5 μg/μL. Nota: Purificare entrambi plasmidi utilizzando un kit di Maxiprep privo di endotossina e sciogliere in soluzione salina bilanciata di Hanks'.</li>
	</ol>
</li>
	<li>
Installazione di apparecchiature di elettroporazione Gli strumenti elettrici come uno stimolatore e un isolatore devono essere collegati come mostrato nella Figura 2.<ol>
<li>Collegare lo stimolatore del sezionatore bifase.</li>
		<li>Collegare un elettrodo (un diametro di 0,2 mm di filo d'argento) al terminale negativo dell'isolatore.</li>
		<li>Collegare un elettrodo (un diametro di 1 mm di filo d'argento) in serie ad un resistore da 100 Ω e il terminale positivo dell'isolatore.</li>
		<li>Collegare l'amplificatore all'oscilloscopio per monitorare se correnti elettriche vengono passate attraverso il resistore misurando la tensione con l'amplificatore.</li>
	</ol>
</li>
	<li>
Preparazione delle pipette in vetro Nota: Due tipi di pipette in vetro vengono utilizzati per espulsione della soluzione plasmide e l'applicazione di impulsi elettrici.<ol>
<li>Rendere le pipette da capillari di vetro con un estrattore di elettrodo.</li>
		<li>Rompere la punta per la pipetta di espulsione (il diametro della punta dovrebbe essere 20-50 μm).</li>
		<li>Levigare e lucidare la punta della pipetta elettrodo con carta vetrata seguita da fuoco-lucidatura (diametro interno dovrebbe essere 50-200 μm). Nota: La punta dell'elettrodo deve essere piana e liscia, come tocca direttamente il tessuto.</li>
	</ol>
</li>
	<li>
Procedura di elettroporazione
	<ol>
<li>Collegare le pipette di espulsione e l'elettrodo per i manipolatori.</li>
		<li>Inserire un filo d'argento (0,2 mm di diametro) nella pipetta elettrodo.</li>
		<li>Allegare la pipetta di espulsione per una siringa da 1 mL con un tubo di plastica.</li>
		<li>Prendere > 5 μL di soluzione di plasmide nella pipetta espulsione di aspirazione di siringa.</li>
		<li>Mettere il coculture sul palco di elettroporazione e inserire l'elettrodo di diametro 1 mm nel terreno di coltura.</li>
		<li>Luogo della pipetta di espulsione il explant thalamic.</li>
		<li>Spingere manualmente la siringa dopo la punta tocca la superficie del blocco thalamic. Nota: Circa 0,5 μL del plasmide soluzione è usato solitamente per un blocco thalamic.</li>
		<li>Inserire la pipetta elettrodo sul blocco thalamic subito dopo retrazione della pipetta espulsione.</li>
		<li>Fornire impulsi elettrici (50-400 μA, treni di 3-5 di 200 impulsi quadrati di durata di 1 ms a 200 Hz). Monitorare l'ampiezza e il numero dei treni sull'oscilloscopio. Nota: L'ampiezza delle correnti elettriche dipende dal diametro interno di un elettrodo pipetta13.</li>
		<li>Ritrarre la pipetta di elettrodo e riporre la piastra nell'incubatore.</li>
	</ol>
</li>
	<li>
Osservazione al microscopio
	<ol>
<li>Mettere la piastra di coltura su un palco al microscopio di un microscopio confocale verticale dotato di due set di filtri per EGFP (eccitazione, 488 nm; emissione, 515 nm) e DsRed (eccitazione, 514 nm; emissione, 565 nm).</li>
		<li>Prendere le immagini di 10-25 sezioni ottiche dimensioni µm-passo 1-7 con un 20 X lungo-lavoro distanza lente dell'obiettivo. Selezionare singolarmente distinguibili con etichettati assoni che esprimono sia DsRed e SYP-EGFP. Nota: L'area osservata è di circa 0,7 x 0,7 mm (corrispondente a 1024 x 1024 pixel, cioè, 0.68 μm/pixel).</li>
		<li>Catturare immagini ogni 24 h per l'imaging quotidiana. Completare entro 10 min a temperatura ambiente e restituire le culture nell'incubatore. Imaging di decadenza breve intervallo di tempo, per mantenere la cultura in un alloggiamento della coltura, che mantiene che l'ambiente di umidificata 95% aria e 5% CO2 a 37 ° C.</li>
	</ol>
</li>
</ol>

<ol>
	<li>Kageyama, G. H., Robertson, R. T. <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+geniculocortical+projections+to+visual+cortex+in+rat:+evidence+early+ingrowth+and+synaptogenesis.">Development of geniculocortical projections to visual cortex in rat: evidence early ingrowth and synaptogenesis.</a> J. Comp. Neurol. 335 (1), 123-148 (1993).</li><li>Lopez-Bendito, G., Molnar, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thalamocortical+development:+how+are+we+going+to+get+there.">Thalamocortical development: how are we going to get there.</a> Nat. Rev. Neurosci. 4 (4), 276-289 (2003).</li><li>Espinosa, J. S., Stryker, M. P. <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+plasticity+of+the+primary+visual+cortex.">Development and plasticity of the primary visual cortex.</a> Neuron. 75 (2), 230-249 (2012).</li><li>Portera-Cailliau, C., Weimer, R. M., De Paola, V., Caroni, P., Svoboda, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diverse+modes+of+axon+elaboration+in+the+developing+neocortex.">Diverse modes of axon elaboration in the developing neocortex.</a> PLoS Biol. 3 (8), 272 (2005).</li><li>Holtmaat, A., Svoboda, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experience-dependent+structural+synaptic+plasticity+in+the+mammalian+brain.">Experience-dependent structural synaptic plasticity in the mammalian brain.</a> Nat. Rev. Neurosci. 10 (9), 647-658 (2009).</li><li>Bhatt, D. H., Zhang, S., Gan, W. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+spine+dynamics.">Dendritic spine dynamics.</a> Annu Rev Physiol. 71, 261-282 (2009).</li><li>Yamamoto, N., Kurotani, T., Toyama, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+connections+between+the+lateral+geniculate+nucleus+and+visual+cortex+in+vitro.">Neural connections between the lateral geniculate nucleus and visual cortex in vitro.</a> Science. 245 (4914), 192-194 (1989).</li><li>Yamamoto, N., Yamada, K., Kurotani, T., Toyama, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laminar+specificity+of+extrinsic+cortical+connections+studied+in+coculture+preparations.">Laminar specificity of extrinsic cortical connections studied in coculture preparations.</a> Neuron. 9 (2), 217-228 (1992).</li><li>Uesaka, N., Hirai, S., Maruyama, T., Ruthazer, E. S., Yamamoto, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activity+dependence+of+cortical+axon+branch+formation:+a+morphological+and+electrophysiological+study+using+organotypic+slice+cultures.">Activity dependence of cortical axon branch formation: a morphological and electrophysiological study using organotypic slice cultures.</a> J. Neurosci. 25 (1), 1-9 (2005).</li><li>Uesaka, N., Hayano, Y., Yamada, A., Yamamoto, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interplay+between+laminar+specificity+and+activity-dependent+mechanisms+of+thalamocortical+axon+branching.">Interplay between laminar specificity and activity-dependent mechanisms of thalamocortical axon branching.</a> J. Neurosci. 27 (19), 5215-5223 (2007).</li><li>Uesaka, N., Nishiwaki, M., Yamamoto, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+cell+electroporation+method+for+axon+tracing+in+cultured+slices.">Single cell electroporation method for axon tracing in cultured slices.</a> Dev. Growth Differ. 50 (6), 475-477 (2008).</li><li>Matsumoto, N., Hoshiko, M., Sugo, N., Fukazawa, Y., Yamamoto, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synapse-dependent+and+independent+mechanisms+of+thalamocortical+axon+branching+are+regulated+by+neuronal+activity.">Synapse-dependent and independent mechanisms of thalamocortical axon branching are regulated by neuronal activity.</a> Dev Neurobiol. 76 (3), 323-336 (2016).</li><li>Matsumoto, N., Sasaki, K., Yamamoto, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation+Method+for+Mammalian+CNS+Neurons+in+Organotypic+Slice+Cultures.">Electroporation Method for Mammalian CNS Neurons in Organotypic Slice Cultures.</a> Electroporation Methods in Neuroscience. , 159-168 (2015).</li><li>Molnar, Z., Blakemore, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lack+of+regional+specificity+for+connections+formed+between+thalamus+and+cortex+in+coculture.">Lack of regional specificity for connections formed between thalamus and cortex in coculture.</a> Nature. 351 (6326), 475-477 (1991).</li><li>Bolz, J., Novak, N., Staiger, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+specific+afferent+connections+in+organotypic+slice+cultures+from+rat+visual+cortex+cocultured+with+lateral+geniculate+nucleus.">Formation of specific afferent connections in organotypic slice cultures from rat visual cortex cocultured with lateral geniculate nucleus.</a> J. Neurosci. 12 (8), 3054-3070 (1992).</li><li>Yamamoto, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibitory+mechanism+by+polysialic+acid+for+lamina-specific+branch+formation+of+thalamocortical+axons.">Inhibitory mechanism by polysialic acid for lamina-specific branch formation of thalamocortical axons.</a> J. Neurosci. 20 (24), 9145-9151 (2000).</li><li>Yamamoto, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+factors+regulating+lamina-specific+growth+of+thalamocortical+axons.">Characterization of factors regulating lamina-specific growth of thalamocortical axons.</a> J Neurobiol. 42 (1), 56-68 (2000).</li><li>Ohnami, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+RhoA+in+activity-dependent+cortical+axon+branching.">Role of RhoA in activity-dependent cortical axon branching.</a> J. Neurosci. 28 (37), 9117-9121 (2008).</li><li>Yamada, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+pre-+and+postsynaptic+activity+in+thalamocortical+axon+branching.">Role of pre- and postsynaptic activity in thalamocortical axon branching.</a> Proc Natl Acad Sci U S A. 107 (16), 7562-7567 (2010).</li></ol>

Gli autori non hanno nulla a rivelare.

Il protocollo attuale è anche un potente strumento per studiare aspetti inerenti allo sviluppo della crescita assoni diversi da quelli dei TC proiezione11. Per esempio, una combinazione di cultura corticale fetta e la tecnica di elettroporazione consente di visualizzare singola axonal morfologia dei neuroni corticali e a lungo termine osservazione9,18.
Utilizzando il protocollo attuale, i ruoli dei geni interes...

La proiezione di thalamocortical (TC) nel cervello dei mammiferi è un sistema adatto per studiare assone di orientamento e di meccanismi di targeting. Durante lo sviluppo, assoni sensoriali TC crescono nella placca corticale e rami di forma e sinapsi preferenzialmente in strato IV delle aree sensoriali primarie in corteccia cerebrale1,2. Anche dopo l'istituzione di collegamenti fondamentali, pergolati assonale e terminali sinaptici sono state rimodernate a seconda dei cambiamenti ambientali3,4. Tuttavia, come la morfologia dell'assone TC dinamicamente è alterata è capita male. Uno dei motivi principali è la mancanza di un'adeguata tecnica di osservare i cambiamenti strutturali a livello di singola cellula. Anche se recenti sviluppi nella microscopia, come il microscopio a due fotoni, hanno permesso l'osservazione diretta dei neuroni corticali vivente in vivo, non ci sono limitazioni ancora tecniche per catturare il generale TC traiettorie5, 6. Pertanto, metodi in vitro per l'imaging dal vivo degli assoni TC sarebbero forniscono potenti strumenti per le analisi strutturali della formazione di ramificazione e sinapsi dell'assone.
Il nostro gruppo per la prima volta stabilito un metodo di coltura slice statico con membrana permeabile7. Utilizzando questo metodo, una fetta di corticali del ratto è stato cocultured con un blocco sensoriale talamico e connessioni TC della lamina specifiche erano ricapitolate in questo organotipiche cocultures7,8. Etichettatura di tipo sparse con una proteina fluorescente ulteriormente ci ha permesso di osservare la crescita assonale TC e ramo formazione9,10,11. Recentemente, abbiamo sviluppato un nuovo metodo per la rappresentazione simultanea di ramificazione e formazione di sinapsi di singoli assoni di TC nell'organotipiche cocultures12. Per visualizzare contemporaneamente TC assoni e siti presinaptici, DsRed e lo synaptophysin EGFP-etichetta (SYP-EGFP) erano co-trasfettate in un piccolo numero di neuroni talamici mediante elettroporazione del coculture organotipiche. Il metodo corrente facilita l'analisi morfologica degli assoni di TC e permette per l'osservazione a lungo termine, che può essere utilizzato per mostrare la relazione causale tra formazione di ramificazione e sinapsi dell'assone.

<table style="border-collapse:collapse;width:344pt" width="459">
	<colgroup>
		<col style="width:113pt" width="151" />
		<col style="width:89pt" width="119" />
		<col style="width:84pt" width="112" />
		<col style="width:58pt" width="77" />
	</colgroup>
	<tbody>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">DMEM/F12</td>
			<td class="xl20" style="width:89pt" width="119">GIBCO</td>
			<td class="xl20" style="width:84pt" width="112">11320-033</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Hanks&#8217; balanced salt solution (HBSS)</td>
			<td class="xl20" style="width:89pt" width="119">Nissui</td>
			<td class="xl21" style="width:84pt" width="112">5905</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Fetal bovine serum (FBS)</td>
			<td class="xl20" style="width:89pt" width="119">Thermo Scientific</td>
			<td class="xl20" style="width:84pt" width="112">SH30396-03</td>
			<td class="xl20" style="width:58pt" width="77">Hyclone</td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Insulin</td>
			<td class="xl20" style="width:89pt" width="119">Sigma</td>
			<td class="xl20" style="width:84pt" width="112">I6634</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Progesterone</td>
			<td class="xl20" style="width:89pt" width="119">Sigma</td>
			<td class="xl20" style="width:84pt" width="112">P8783</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Hydrocortisone</td>
			<td class="xl20" style="width:89pt" width="119">Sigma&#160;</td>
			<td class="xl20" style="width:84pt" width="112">H0888</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Sodium selenite</td>
			<td class="xl20" style="width:89pt" width="119">Wako Pure 
			Chemical Industries</td>
			<td class="xl20" style="width:84pt" width="112">192-10843</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Transferrin&#160;</td>
			<td class="xl20" style="width:89pt" width="119">Sigma</td>
			<td class="xl20" style="width:84pt" width="112">T1147</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Putrescine&#160;</td>
			<td class="xl20" style="width:89pt" width="119">Sigma</td>
			<td class="xl20" style="width:84pt" width="112">P5780</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Glucose</td>
			<td class="xl20" style="width:89pt" width="119">Wako 
			Pure Chemical Industries</td>
			<td class="xl20" style="width:84pt" width="112">16806-25</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">35 mm petri dishes</td>
			<td class="xl20" style="width:89pt" width="119">Falcon</td>
			<td class="xl21" style="width:84pt" width="112">351008</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Millicell-CM insert</td>
			<td class="xl20" style="width:89pt" width="119">Millipore</td>
			<td class="xl20" style="width:84pt" width="112">PICMORG50</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">100 mm petri dishes</td>
			<td class="xl20" style="width:89pt" width="119">BIO-BIK</td>
			<td class="xl20" style="width:84pt" width="112">I-90-20</td>
			<td class="xl20" style="width:58pt" width="77">petri dish sterrile</td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">HiPure Plasmid Maxiprep Kit</td>
			<td class="xl20" style="width:89pt" width="119">Invitrogen</td>
			<td class="xl20" style="width:84pt" width="112">K210006</td>
			<td class="xl23" style="width:58pt" width="77"></td>
		</tr>
		<tr height="59" style="height:44.25pt">
			<td class="xl20" height="59" style="width:113pt;height:44.25pt" width="151">Disposable sterile plastic pipettes</td>
			<td class="xl20" style="width:89pt" width="119"></td>
			<td class="xl20" style="width:84pt" width="112">202-IS</td>
			<td class="xl20" style="width:58pt" width="77">transfer pipets sterile</td>
		</tr>
		<tr height="54" style="height:40.5pt">
			<td class="xl20" height="54" style="width:113pt;height:40.5pt" width="151">Glass capillary: OD 1.2 mm</td>
			<td class="xl20" style="width:89pt" width="119">Narishige</td>
			<td class="xl20" style="width:84pt" width="112">&#160;G-1.2</td>
			<td class="xl20" style="width:58pt" width="77">inner diameter, 1.2 mm</td>
		</tr>
		<tr height="53" style="height:39.75pt">
			<td class="xl20" height="53" style="width:113pt;height:39.75pt" width="151">Silver wire: 0.2 and 1 mm&#160;</td>
			<td class="xl20" style="width:89pt" width="119">Nilaco</td>
			<td class="xl20" style="width:84pt" width="112">AG-401265 (diameter, 0.2 mm), AG-401485 (diameter, 1.0 mm)</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">1 mL syringe</td>
			<td class="xl20" style="width:89pt" width="119">Terumo</td>
			<td class="xl20" style="width:84pt" width="112">SS-01T</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Stimulator&#160;</td>
			<td class="xl20" style="width:89pt" width="119">A.M.P.I</td>
			<td class="xl20" style="width:84pt" width="112">Master 8</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Biphasic isolator&#160;</td>
			<td class="xl20" style="width:89pt" width="119">BAK ELECTRONICS</td>
			<td class="xl20" style="width:84pt" width="112">BSI-2</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Amplifier&#160;</td>
			<td class="xl20" style="width:89pt" width="119">A-M Systems</td>
			<td class="xl20" style="width:84pt" width="112">Model 1800</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Oscilloscope</td>
			<td class="xl20" style="width:89pt" width="119">Hitachi</td>
			<td class="xl20" style="width:84pt" width="112">VC-6723</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Manipulator</td>
			<td class="xl20" style="width:89pt" width="119">Narishige</td>
			<td class="xl20" style="width:84pt" width="112">SM-15</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Micromanipulator</td>
			<td class="xl20" style="width:89pt" width="119">Narishige</td>
			<td class="xl20" style="width:84pt" width="112">MO-10</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Stereomicroscope&#160;</td>
			<td class="xl20" style="width:89pt" width="119">Olympus</td>
			<td class="xl20" style="width:84pt" width="112">SZ40</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Universal stand&#160;</td>
			<td class="xl20" style="width:89pt" width="119">Olympus</td>
			<td class="xl20" style="width:84pt" width="112">SZ-STU2</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Light illumination system&#160;</td>
			<td class="xl20" style="width:89pt" width="119">Olympus</td>
			<td class="xl20" style="width:84pt" width="112">LG-PS2, LG-DI, HLL301</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Electrode puller&#160;</td>
			<td class="xl20" style="width:89pt" width="119">Narishige</td>
			<td class="xl20" style="width:84pt" width="112">PC-10</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Confocal microscope</td>
			<td class="xl20" style="width:89pt" width="119">Nikon</td>
			<td class="xl20" style="width:84pt" width="112">Digital eclipse C1 laser</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">x20 objective</td>
			<td class="xl20" style="width:89pt" width="119">Nikon</td>
			<td class="xl20" style="width:84pt" width="112">ELWD 20x/0.45</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Culture chamber</td>
			<td class="xl20" style="width:89pt" width="119">Tokai Hit</td>
			<td class="xl20" style="width:84pt" width="112">UK A16-U</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Sprague-Dawley (SD) rat</td>
			<td class="xl20" style="width:89pt" width="119">Japan SLC and Nihon-Dobutsu</td>
			<td class="xl20" style="width:84pt" width="112"></td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
		<tr height="40" style="height:30.0pt">
			<td class="xl20" height="40" style="width:113pt;height:30.0pt" width="151">Microsurgery scissors</td>
			<td class="xl20" style="width:89pt" width="119">Natsume&#160;</td>
			<td class="xl20" style="width:84pt" width="112">MB-54-1</td>
			<td class="xl20" style="width:58pt" width="77"></td>
		</tr>
	</tbody>
</table>

visualization of thalamocortical axon branching and synapse formation in organotypic cocultures

Formazione di ramificazione e sinapsi dell'assone sono processi cruciali per stabilire precisi circuiti neuronali. Durante lo sviluppo, gli assoni sensoriali thalamocortical (TC) formano rami e sinapsi in livelli specifici della corteccia cerebrale. Nonostante l'evidente correlazione spaziale tra formazione di ramificazione e sinapsi dell'assone, la relazione causale tra di loro è capita male. Per risolvere questo problema, abbiamo recentemente sviluppato un metodo per l'acquisizione simultanea delle formazione ramificazione e sinapsi dei singoli assoni di TC in cocultures organotipiche.
Questo protocollo descrive un metodo che consiste di una combinazione di un coculture organotipiche e l'elettroporazione. Organotipiche cocultures del talamo e corteccia cerebrale facilitare la manipolazione del gene e l'osservazione dei processi di axonal, preservando le strutture caratteristiche come configurazione laminare. Due plasmidi distinti codifica DsRed e lo synaptophysin EGFP-etichetta (SYP-EGFP) sono state co-trasfettate in un piccolo numero di neuroni talamici da una tecnica di elettroporazione. Questo metodo ci ha permesso di visualizzare singole axonal morfologie dei neuroni di TC e loro siti presinaptici simultaneamente. Il metodo attivato anche l'osservazione a lungo termine che ha rivelato il rapporto causale fra formazione di ramificazione e sinapsi dell'assone.

L'esperimento qui descritto mira a rivelare la relazione tra formazione di ramificazione e sinapsi dell'assone TC. Per visualizzare contemporaneamente axonal traiettorie e posizioni dei siti presinaptici, singoli o poche cellule thalamic in cocultures organotipiche transfected con due plasmidi codifica SYP-EGFP e DsRed usando l'elettroporazione. Durante la seconda settimana di cultura, gli assoni TC individualmente distinguibili erano chiaramente etichettati da DsRed (<strong class="xfig"...

Watch this Scientific Journal Video about Visualization of Thalamocortical Axon Branching and Synapse Formation in Organotypic Cocultures at JoVE.com

Visualization of Thalamocortical Axon Branching and Synapse Formation in Organotypic Cocultures

Questo protocollo descrive un metodo per l'acquisizione simultanea delle thalamocortical assone ramificazione e sinapsi formazione in organotipiche cocultures del talamo e corteccia cerebrale. Thalamocortical singoli assoni e loro terminali presinaptici sono visualizzati mediante una tecnica di elettroporazione di singola cellula con DsRed e lo synaptophysin GFP-etichettato.

Visualizzazione di Thalamocortical Axon ramificazione e Synapse formazione in Cocultures organotipiche

Axon branching and synapse formation are crucial processes for establishing precise neuronal circuits. During development, sensory thalamocortical (TC) ...

visualization-thalamocortical-axon-branching-synapse-formation

Research

JoVE Journal

Neuroscience

6.4K Views.  Kanazawa University. Questo protocollo descrive un metodo per l'acquisizione simultanea delle thalamocortical assone ramificazione e sinapsi formazione in organotipiche cocultures del talamo e corteccia cerebrale. Thalamocortical singoli assoni e loro terminali presinaptici sono visualizzati mediante una tecnica di elettroporazione di singola cellula con DsRed e lo synaptophysin GFP-etichettato.

Video: Visualization of Thalamocortical Axon Branching and Synapse Formation in Organotypic Cocultures

Automated Interactive Video Playback for Studies of Animal Communication

Video playback is a widely-used technique for the controlled manipulation and presentation of visual signals in animal communication. In particular, parameter-based computer animation offers the opportunity to independently manipulate any number of behavioral, morphological, or spectral characteristics in the context of realistic, moving images of animals on screen. A major limitation of conventional playback, however, is that the visual stimulus lacks the ability to interact with the live animal. Borrowing from video-game technology, we have created an automated, interactive system for video playback that controls animations in response to real-time signals from a video tracking system. We demonstrated this method by conducting mate-choice trials on female swordtail fish, Xiphophorus birchmanni. Females were given a simultaneous choice between a courting male conspecific and a courting male heterospecific (X. malinche) on opposite sides of an aquarium. The virtual male stimulus was programmed to track the horizontal position of the female, as courting males do in the wild. Mate-choice trials on wild-caught X. birchmanni females were used to validate the prototype's ability to effectively generate a realistic visual stimulus.

Video playback is a widely used technique in animal behavior. We created and evaluated a program that applies rules-based, interactive playback of 3-D computer animations in response to real-time, automated data on subject behavior.

Riproduzione automatica Interactive Video per gli Studi di comunicazione animale

Video playback is a widely-used technique for the controlled manipulation and presentation of visual signals in animal communication. In particular, ...

Ricerca

Neuroscienze

Visualization of Proprioceptors in Drosophila Larvae and Pupae

Proprioception is the ability to sense the motion, or position, of body parts by responding to stimuli arising within the body. In fruitflies and other insects proprioception is provided by specialized sensory organs termed chordotonal organs (ChOs) 2. Like many other organs in Drosophila, ChOs develop twice during the life cycle of the fly. First, the larval ChOs develop during embryogenesis. Then, the adult ChOs start to develop in the larval imaginal discs and continue to differentiate during metamorphosis.
The development of larval ChOs during embryogenesis has been studied extensively 10,11,13,15,16. The centerpiece of each ChO is a sensory unit composed of a neuron and a scolopale cell. The sensory unit is stretched between two types of accessory cells that attach to the cuticle via specialized epidermal attachment cells 1,9,14. When a fly larva moves, the relative displacement of the epidermal attachment cells leads to stretching of the sensory unit and consequent opening of specific transient receptor potential vanilloid (TRPV) channels at the outer segment of the dendrite 8,12. The elicited signal is then transferred to the locomotor central pattern generator circuit in the central nervous system.
Multiple ChOs have been described in the adult fly 7. These are located near the joints of the adult fly appendages (legs, wings and halters) and in the thorax and abdomen. In addition, several hundreds of ChOs collectively form the Johnston's organ in the adult antenna that transduce acoustic to mechanical energy 3,5,17,4.
In contrast to the extensive knowledge about the development of ChOs in embryonic stages, very little is known about the morphology of these organs during larval stages. Moreover, with the exception of femoral ChOs 18 and Johnston's organ, our knowledge about the development and structure of ChOs in the adult fly is very fragmentary.
Here we describe a method for staining and visualizing ChOs in third instar larvae and pupae. This method can be applied together with genetic tools to better characterize the morphology and understand the development of the various ChOs in the fly.

Visualization of Proprioceptors in Drosophila Larvae and Pupae

A method to immunostain and visualize chordotonal organs in larvae and pupae of Drosophila melanogaster is described.

Visualizzazione dei Propriorecettori in<em&gt; Drosophila</em&gt; Larve e pupe

Proprioception is the ability to sense the motion, or position, of body parts by responding to stimuli arising within the body. In fruitflies and other ...

Paired Whole Cell Recordings in Organotypic Hippocampal Slices

Pair recordings involve simultaneous whole cell patch clamp recordings from two synaptically connected neurons, enabling not only direct electrophysiological characterization of the synaptic connections between individual neurons, but also pharmacological manipulation of either the presynaptic or the postsynaptic neuron. When carried out in organotypic hippocampal slice cultures, the probability that two neurons are synaptically connected is significantly increased. This preparation readily enables identification of cell types, and the neurons maintain their morphology and properties of synaptic function similar to that in native brain tissue. A major advantage of paired whole cell recordings is the highly precise information it can provide on the properties of synaptic transmission and plasticity that are not possible with other more crude techniques utilizing extracellular axonal stimulation. Paired whole cell recordings are often perceived as too challenging to perform. While there are challenging aspects to this technique, paired recordings can be performed by anyone trained in whole cell patch clamping provided specific hardware and methodological criteria are followed. The probability of attaining synaptically connected paired recordings significantly increases with healthy organotypic slices and stable micromanipulation allowing independent attainment of pre- and postsynaptic whole cell recordings. While CA3-CA3 pyramidal cell pairs are most widely used in the organotypic slice hippocampal preparation, this technique has also been successful in CA3-CA1 pairs and can be adapted to any neurons that are synaptically connected in the same slice preparation. In this manuscript we provide the detailed methodology and requirements for establishing this technique in any laboratory equipped for electrophysiology.

Pair recordings are simultaneous whole cell patch clamp recordings from two synaptically connected neurons, enabling precise electrophysiological and pharmacological characterization of the synapses between individual neurons. Here we describe the detailed methodology and requirements for establishing this technique in organotypic hippocampal slice cultures in any laboratory equipped for electrophysiology.

Associati a cellule intere registrazioni in organotipiche fettine di ippocampo

Pair recordings involve simultaneous whole cell patch clamp recordings from two synaptically connected neurons, enabling not only direct ...

Inhibitory Synapse Formation in a Co-culture Model Incorporating GABAergic Medium Spiny Neurons and HEK293 Cells Stably Expressing GABAA Receptors

Inhibitory neurons act in the central nervous system to regulate the dynamics and spatio-temporal co-ordination of neuronal networks. GABA (&#947;-aminobutyric acid) is the predominant inhibitory neurotransmitter in the brain. It is released from the presynaptic terminals of inhibitory neurons within highly specialized intercellular junctions known as synapses, where it binds to GABAA receptors (GABAARs) present at the plasma membrane of the synapse-receiving, postsynaptic neurons. Activation of these GABA-gated ion channels leads to influx of chloride resulting in postsynaptic potential changes that decrease the probability that these neurons will generate action potentials. 
During development, diverse types of inhibitory neurons with distinct morphological, electrophysiological and neurochemical characteristics have the ability to recognize their target neurons and form synapses which incorporate specific GABAARs subtypes. This principle of selective innervation of neuronal targets raises the question as to how the appropriate synaptic partners identify each other. 
To elucidate the underlying molecular mechanisms, a novel in vitro co-culture model system was established, in which medium spiny GABAergic neurons, a highly homogenous population of neurons isolated from the embryonic striatum, were cultured with stably transfected HEK293 cell lines that express different GABAAR subtypes. Synapses form rapidly, efficiently and selectively in this system, and are easily accessible for quantification. Our results indicate that various GABAAR subtypes differ in their ability to promote synapse formation, suggesting that this reduced in vitro model system can be used to reproduce, at least in part, the in vivo conditions required for the recognition of the appropriate synaptic partners and formation of specific synapses. Here the protocols for culturing the medium spiny neurons and generating HEK293 cells lines expressing GABAARs are first described, followed by detailed instructions on how to combine these two cell types in co-culture and analyze the formation of synaptic contacts.

Inhibitory Synapse Formation in a Co-culture Model Incorporating GABAergic Medium Spiny Neurons and HEK293 Cells Stably Expressing GABAA Receptors

The molecular mechanisms that co-ordinate the formation of inhibitory GABAergic synapses during ontogeny are largely unknown. To study these processes,we have developed a co-culture model system which incorporates embryonic medium spiny GABAergic neurons cultured together with stably transfected human embryonic kidney 293 (HEK293) cells expressing functional GABAA receptors.

Inibitorio formazione di sinapsi in un co-coltura modello che incorpora GABAergici di medie spinosa neuroni e cellule HEK293 che esprimono stabilmente GABA<sub&gt; A</sub&gt; Recettori

Inhibitory neurons act in the central nervous system to regulate the dynamics and spatio-temporal co-ordination of neuronal networks. GABA ...

Whole-mount Imaging of Mouse Embryo Sensory Axon Projections

The visualization of full-length neuronal projections in embryos is essential to gain an understanding of how mammalian neuronal networks develop. Here we describe a method to label in situ a subset of dorsal root ganglion (DRG) axon projections to assess their phenotypic characteristics using several genetically manipulated mouse lines. The TrkA-positive neurons are nociceptor neurons, dedicated to the transmission of pain signals. We utilize a TrkAtaulacZ mouse line to label the trajectories of all TrkA-positive peripheral axons in the intact mouse embryo. We further breed the TrkAtaulacZ line onto a Bax null background, which essentially abolishes neuronal apoptosis, in order to assess growth-related questions independently of possible effects of genetic manipulations on neuronal survival. Subsequently, genetically modified mice of interest are bred with the TrkAtaulacZ/Bax null line and are then ready for study using the techniques described herein. This presentation includes detailed information on mouse breeding plans, genotyping at the time of dissection, tissue preparation, staining and clearing to allow for visualization of full-length axonal trajectories in whole-mount preparation.

We present here an optimized protocol to genotype, stain and prepare fetal mice for the imaging of peripheral nociceptor axon projections in the whole animal, as an effective method to assess sensory axon growth phenotypes in developing genetically engineered mice.

Whole-mount Imaging di embrione di topo Sensory Axon Proiezioni

The visualization of full-length neuronal projections in embryos is essential to gain an understanding of how mammalian neuronal networks develop. Here we ...

Utilizing Combined Methodologies to Define the Role of Plasma Membrane Delivery During Axon Branching and Neuronal Morphogenesis

During neural development, growing axons extend to multiple synaptic partners by elaborating axonal branches. Axon branching is promoted by extracellular guidance cues like netrin-1 and results in dramatic increases to the surface area of the axonal plasma membrane. Netrin-1-dependent axon branching likely involves temporal and spatial control of plasma membrane expansion, the components of which are supplied through exocytic vesicle fusion. These fusion events are preceded by formation of SNARE complexes, comprising a v-SNARE, such as VAMP2 (vesicle-associated membrane protein 2), and plasma membrane t-SNAREs, syntaxin-1 and SNAP25 (synaptosomal-associated protein 25). Detailed herein isa multi-pronged approach used to examine the role of SNARE mediated exocytosis in axon branching. The strength of the combined approach is data acquisition at a range of spatial and temporal resolutions, spanning from the dynamics of single vesicle fusion events in individual neurons to SNARE complex formation and axon branching in populations of cultured neurons. This protocol takes advantage of established biochemical approaches to assay levels of endogenous SNARE complexes and Total Internal Reflection Fluorescence (TIRF) microscopy of cortical neurons expressing VAMP2 tagged with a pH-sensitive GFP (VAMP2-pHlourin) to identify netrin-1 dependent changes in exocytic activity in individual neurons. To elucidate the timing of netrin-1-dependent branching, time-lapse differential interference contrast (DIC) microscopy of single neurons over the order of hours is utilized. Fixed cell immunofluorescence paired with botulinum neurotoxins that cleave SNARE machinery and block exocytosis demonstrates that netrin-1 dependent axon branching requires SNARE-mediated exocytic activity.

Light microscopy techniques coupled with biochemical assays elucidate the involvement of SNARE-mediated exocytosis in netrin-dependent axon branching. This combination of techniques permits identification of molecular mechanisms controlling axon branching and cell shape change.

Utilizzando metodologie combinati per definire il ruolo della membrana plasmatica di consegna Durante Axon ramificazione e neuronale morfogenesi

During neural development, growing axons extend to multiple synaptic partners by elaborating axonal branches. Axon branching is promoted by extracellular ...

Quadruple Immunostaining of the Olfactory Bulb for Visualization of Olfactory Sensory Axon Molecular Identity Codes

The mouse olfactory system is often used to study mechanisms of neural circuit formation&#12288;because of its simple anatomical structure. An Olfactory Sensory Neuron (OSN) is a bipolar cell with a single dendrite and a single unbranched axon. An OSN expresses only one Olfactory Receptor (OR) gene, OSNs expressing a given type of OR converge their axons to a few sets of invariant glomeruli in the Olfactory Bulb (OB). A remarkable feature of OSN projection is that the expressed ORs play instructive roles in axonal projection. ORs regulate the expression of multiple axon-sorting molecules and generate the combinatorial molecular code of axon-sorting molecules at the OSN axon termini. Thus, to understand the molecular mechanisms of OR-specific axon guidance mechanisms, it is vital to characterize their expression profiles at the OSN axon termini within the same glomerulus. The aim of this article was to introduce methods for collecting as many glomeruli as possible on a single OB section and for performing immunostaining using multiple antibodies. This would allow the comparison and analysis of the expression patterns of axon-sorting molecules without staining variation between OB sections.

Olfactory sensory neurons express a wide variety of axon-sorting molecules to establish proper neural circuitry. This protocol describes an immunohistochemical staining method to visualize combinatorial expressions of axon-sorting molecules at the axon termini of olfactory sensory neurons.

Quadrupla Immunostaining della lampadina olfattiva per la visualizzazione di codici di identificazione molecolare Axon sensoriale olfattiva

The mouse olfactory system is often used to study mechanisms of neural circuit formation&#12288;because of its simple anatomical structure. An Olfactory ...

Improving the Application of High Molecular Weight Biotinylated Dextran Amine for Thalamocortical Projection Tracing in the Rat

High molecular weight biotinylated dextran amine (BDA) has been used as a highly sensitive neuroanatomical tracer for many decades. Since the quality of its labeling was affected by various factors, here, we provide a refined protocol for the application of high molecular weight BDA for studying optimal neural labeling in the central nervous system. After stereotactic injection of BDA into the ventral posteromedial nucleus (VPM) of the thalamus in the rat through a delicate glass pipette, BDA was stained with fluorescent streptavidin-Alexa (AF) 594 and counterstained with fluorescent Nissl stain AF500/525. On the background of green Nissl staining, the red BDA labeling, including neuronal cell bodies and axonal terminals, was more distinctly demonstrated in the somatosensory cortex. Furthermore, double fluorescent staining for BDA and the calcium-binding protein parvalbumin (PV) was carried out to observe the correlation of BDA labeling and PV-positive interneurons in the cortical target, providing the opportunity to study the local neural circuits and their chemical characteristics. Thus, this refined method is not only suitable for visualizing high quality neural labeling with the high molecular weight BDA through reciprocal neural pathways between the thalamus and cerebral cortex, but also will permit the simultaneous demonstration of other neural markers with fluorescent histochemistry or immunochemistry.

Here, we present a refined protocol to effectively reveal biotinylated dextran amine (BDA) labeling with a fluorescent staining method through a reciprocal neural pathway. It is suitable for analyzing the fine structure of BDA labeling and distinguishing it from other neural elements under a confocal laser scanning microscope.

Migliorare l'applicazione di alto peso molecolare del dextrano Biotinylated ammina per proiezione Thalamocortical traccia nel ratto

High molecular weight biotinylated dextran amine (BDA) has been used as a highly sensitive neuroanatomical tracer for many decades. Since the quality of ...

Evaluation of Synapse Density in Hippocampal Rodent Brain Slices

In the brain, synapses are specialized junctions between neurons, determining the strength and spread of neuronal signaling. The number of synapses is tightly regulated during development and neuronal maturation. Importantly, deficits in synapse number can lead to cognitive dysfunction. Therefore, the evaluation of synapse number is an integral part of neurobiology. However, as synapses are small and highly compact in the intact brain, the assessment of absolute number is challenging. This protocol describes a method to easily identify and evaluate synapses in hippocampal rodent slices using immunofluorescence microscopy. It includes a three-step procedure to evaluate synapses in high-quality confocal microscopy images by analyzing the co-localization of pre- and postsynaptic proteins in hippocampal slices. It also explains how the analysis is performed and gives representative examples from both excitatory and inhibitory synapses. This protocol provides a solid foundation for the analysis of synapses and can be applied to any research investigating the structure and function of the brain.

A protocol for accurately identifying and analyzing synapses in hippocampal slices using immunofluorescence is outlined in this article.

Valutazione di densità di sinapsi nelle fette Hippocampal del cervello del roditore

In the brain, synapses are specialized junctions between neurons, determining the strength and spread of neuronal signaling. The number of synapses is ...

Visualization and Live Imaging of Oligodendrocyte Organelles in Organotypic Brain Slices Using Adeno-associated Virus and Confocal Microscopy

Neurons rely on the electric insulation and trophic support of myelinating oligodendrocytes. Despite the importance of oligodendrocytes, the advanced tools currently used to study neurons, have only partly been taken on by oligodendrocyte researchers. Cell type-specific staining by viral transduction is a useful approach to study live organelle dynamics. This paper describes a protocol for visualizing oligodendrocyte mitochondria in organotypic brain slices by transduction with adeno-associated virus (AAV) carrying genes for mitochondrial targeted fluorescent proteins under the transcriptional control of the myelin basic protein promoter. It includes the protocol for making organotypic coronal mouse brain slices. A procedure for time-lapse imaging of mitochondria then follows. These methods can be transferred to other organelles and may be particularly useful for studying organelles in the myelin sheath. Finally, we describe a readily available technique for visualization of unstained myelin in living slices by Confocal Reflectance microscopy (CoRe). CoRe requires no extra equipment and can be useful to identify the myelin sheath during live imaging.

Myelinating oligodendrocytes promote rapid action potential propagation and neuronal survival. Described here is a protocol for oligodendrocyte-specific expression of fluorescent proteins in organotypic brain slices with subsequent time-lapse imaging. Further, a simple procedure for visualizing unstained myelin is presented.

Visualizzazione e Live Imaging del Oligodendrocyte organelli in fettine di cervello Organotypic utilizzando Virus Adeno-associati e microscopia confocale

Neurons rely on the electric insulation and trophic support of myelinating oligodendrocytes. Despite the importance of oligodendrocytes, the advanced ...