Questo lavoro è stato finanziato da sovvenzioni dal National Institutes of Health: EY015748, EY017964 (MEZ), e EY019517 (ASV). Questo lavoro è stato supportato anche dalla ricerca per la prevenzione cecità illimitato Sovvenzione al reparto di Oculistica ed i Lions di Central New York. Vorremmo anche ringraziare il nostro tecnico animali, Matteo Mellini, per la sua eccellente cura degli animali e intervenendo per recitare in questo video.

Animal Care Il Xenopus laevis girini utilizzati in questo studio sono stati coltivati, allevati e trattati secondo le procedure approvate dal Upstate Medical University IACUC e la Guida per la cura e l&#39;uso di animali da laboratorio. 1. Impostazione Pre-comportamento: Girini <ol><li> Ottenere fecondati embrioni di Xenopus da una sorgente disponibile in commercio o in vitro fecondare ovociti, come descritto in precedenza 6. </li><li> Posizionare blastula a neurali embrioni stadio piastra a 18 ˚ C in 60 millimetri piastre Petri contenenti 0,1 X. MMR [10 X Marc Modificato soluzione (MMR) stock Ringer (10 mM MgCl 2, 20 mM KCl, 20 mM CaCl 2; 50 HEPES mM; 1 M NaCl, regolata a pH 7,5, autoclavato e conservati a RT)] con 50 ug / ml di gentamicina antibiotico. Cambiare 0,1 X. MMR ogni giorno e rimuovere eventuali embrioni morti. </li><li> Una volta che gli embrioni raggiungono Nieuwkoop e Faber fase ~ 27-30 Luglio, passare the embrioni in 0,1 X. MMR senza antibiotico per permettere la crescita batterica intestinale. </li><li> Crescere i girini fino a raggiungere lo stadio di alimentazione (fase 45) e spostarli in 100 millimetri piastre di Petri riempite con 0,1 X. MMR. Alimentarli ortica surnatante polvere ogni altro giorno per una settimana, cambiando il 0,1 X. MMR il giorno intermedio. </li><li> Dopo una settimana in piatto 100 millimetri Petri, spostare gli animali per mezzo gallone vasche piene d&#39;acqua rana [0.5 g / L oceano immediata e 2 mM sodio fosfato bibasico (Na 2 HPO 4: mw 141,96) pH 6,8]. Dar loro da mangiare come al punto 2.4, ma cambiare l&#39;acqua solo 2-3 volte a settimana quando l&#39;acqua è torbida. Mantenere gli animali in una 12 ore light/12 ciclo di luce buio con le luci accendere alle 06:00. </li><li> Posizionare il serbatoio mezzo gallone con i soggetti del test su una superficie bianca, come un underpad banco di laboratorio, almeno 12 ore O / N, prima del test. </li><li> Girini di prova nelle fasi 45-50 come descritto nel passaggio 3 di seguito. </li></ol> . 2 Setup Pre-comportamento: Equipment <ol><li> Mettere da parte una zona del laboratorio per il saggio comportamento. Dovrebbe essere in una tranquilla zona a traffico limitato con l&#39;illuminazione fluorescente standard. </li><li> Preparare le vasche di prova per gli animali. I nidificate, serbatoi di test mezzo gallone sono composti da due parti: un serbatoio interno che conterrà l&#39;acqua e girini; e un serbatoio esterno con stimolo visivo. <ol><li> Per il serbatoio interno, fare un piccolo segno sugli angoli esterni con un pennarello, 5 cm dal fondo; questa è la linea di galleggiamento (Figura 1A, linea tratteggiata verde). </li><li> Inoltre, per il serbatoio interno, riempire le divets nel serbatoio (agli angoli e al centro) con un composto inerte, come Sylgard elastomero. NOTA: I girini si soffermerà in queste aree se non vengono riempiti dentro </li><li> Per il serbatoio esterno, coprire esattamente la metà della parte esterna di un serbatoio con nastro isolante nero e l&#39;altra metà con il bianco fazzoletto di carta Figura 1B. </li></ol></li><li> Posizionare i carri armati sulinoculando giradischi. </li><li> Setup la webcam / treppiede in modo che sia sopra le vasche di prova. Regolare la telecamera per permettere la visualizzazione della zona test, come mostrato nella Figura 1C. </li><li> Collegare la webcam di un computer con software QuickTime Player installato 5. Accendere la fotocamera. In QuickTime Player, in File, selezionare &#39;Nuova registrazione filmato.&#39; Il setup del test comportamento sarà visibile sul computer subito. </li><li> Drappo un panno di cotone leggero su tutta la configurazione di ridurre stimoli esterni che potrebbero influenzare il comportamento girino, nonché, ridurre la luce riflessa sulla superficie dell&#39;acqua. </li><li> Assicurarsi che la luminanza nel quadro delle misure di stoffa tra 35-50 cd / m 2. </li></ol> 3. Assay Comportamento <ol><li> Riempire il serbatoio di test interno al segno cinque centimetri di acqua fatta al passo 1.2.1 con acqua rana. </li><li> Usando una piccola rete, spostare delicatamente l&#39;animale nel serbatoio testing interno. </li><li> Aperto QuickTime software sul computer e, con il serbatoio esterno come una guida, assicurarsi che la fotocamera è in grado di visualizzare e registrare l&#39;area di prova. </li><li> Scrivere il nome dell&#39;animale, la data e l&#39;ora su un pezzo di carta e registrare con la macchina fotografica. </li><li> Posizionare il serbatoio di prova nel serbatoio esterno con il lato nero del serbatoio a destra Figura 2. </li><li> Avviare la registrazione del filmato subito dopo aver sistemato il serbatoio e impostare timer per 2 min. </li><li> Quando i segnali acustici del timer, rimuovere il serbatoio di prova interno, ruotare il serbatoio esterno di 180 ° e posizionare il serbatoio di prova interno all&#39;interno del serbatoio esterno. Avviare il timer. Nota: il lato nero dovrebbe essere sull&#39;altro lato. </li><li> Ripetere passo 3.7, più otto volte per un totale di dieci prove. Utilizzare la figura 2 come una guida, controllando fuori di ogni prova. </li><li> Ripetere l&#39;analisi condotta in due giorni separati. </li></ol> 4. Retinica assotomia <ol><li> Mettere animali a 0,02% tricaine fino a che non rispondonoad un pizzico di coda con un # 3 pinze. </li><li> Sciogliere 1% agarosio in 0,1 X. MMR e quindi aggiungere ad una piastra di Petri 60 millimetri. Una volta raffreddato, fare un piccolo incavo rettangolare in agarosio e aggiungere il girino a incavo con un po &#39;0,02% tricaine, in modo che l&#39;animale è parzialmente immersa nel liquido. </li><li> Ago nella pelle ad un angolo di 45 gradi dietro la regione dorsale dell&#39;occhio con un ago 25 G, mentre il rinforzo animale contro pinza sul lato opposto. </li><li> Facendo attenzione a non tagliare la vena, che si trova accanto al nervo ottico, raggiungono attenzione nel foro con # 5 pinze, tagliare il nervo ottico e capovolgere fuori strada. Se c&#39;è sanguinamento grave a causa accidentalmente snipping l&#39;arteria, quindi posizionare rapidamente l&#39;animale in 2% tricaine di eutanasia. ATTENZIONE: Soluzione tricaine 2% può causare intorpidimento negli esseri umani. Questa soluzione deve essere maneggiato con i guanti. </li><li> Per recuperare l&#39;animale dopo l&#39;intervento chirurgico, collocare animale da 100 mm piastra di Petri con 0,7 X MMR e gentamicina 50 mg / ml per 20 min. Next, trasferimento girino al serbatoio di recupero con acqua rana. Lasciate riposare animale O / N. </li><li> La mattina successiva, testare la funzione visiva come descritto sopra (punti 3,1-3,9). </li></ol> 5. Analisi dei risultati <ol><li> Dopo le prove sono finite, misurare la quantità di tempo girino rimane sul lato nero del serbatoio. <ol><li> Visualizzare manualmente i video utilizzando un software che visualizza l&#39;ora e permette frequenti pausa. Guardate il tempo di visualizzazione video. Annotare l&#39;inizio della prova di due minuti, che è quando il recipiente interno nidi successo all&#39;interno della vasca esterna e viene squadrato in vista della telecamera. </li><li> Utilizzare la posizione degli occhi del girino per definire quale lato della vasca gli animali sono il nuoto su. Definire attraversando da un lato del serbatoio all&#39;altro solo quando entrambi gli occhi hanno attraversato il / linea bianca nera. </li></ol></li><li> Annotare l&#39;inizio e la fine di ciascun intervallo (in secondi) che l&#39;animale trascorre sul lato nero. Pausa e riavvolgere il video per garantire la precisione. Il totale del sec all&#39;interno di ogni prova. </li><li> Ingresso questi numeri nel foglio di lavoro Behavior allegato. Il foglio calcola la proporzione di tempo che l&#39;animale ha speso sul lato bianco sottraendo il tempo speso per il lato nero del serbatoio dal totale 120 prova sec e dividere per il tempo totale in sec [(120 - secondi totali spesi il lato nero) / 120 sec]. Le medie del foglio di lavoro questo rapporto su tutte le 10 prove. </li><li> Usa T-test di uno studente, in coppia, distribuzione a due code per determinare se le prove tra le giornate sono significative (P ≤ 0,05). </li></ol>

<ol>
	<li>Maurer, C. M., Huang, Y. Y., Neuhauss, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+zebrafish+oculomotor+behavior+to+model+human+disorders.">Application of zebrafish oculomotor behavior to model human disorders.</a> Rev Neurosci. 22 (1), 5-16 (2011).</li><li>Solessio, E., Scheraga, D., Engbretson, G. A., Knox, B. E., Barlow, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circadian+modulation+of+temporal+properties+of+the+rod+pathway+in+larval+Xenopus.">Circadian modulation of temporal properties of the rod pathway in larval Xenopus.</a> J Neurophysiol. 92 (5), 2672-2684 (2004).</li><li>Moriya, T., Kito, K., Miyashita, Y., Asami, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preference+for+background+color+of+the+Xenopus+laevis+tadpole.">Preference for background color of the Xenopus laevis tadpole.</a> J Exp Zool. 276 (5), 335-344 (1996).</li><li>Viczian, A. S., Solessio, E. C., Lyou, Y., Zuber, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+functional+eyes+from+pluripotent+cells.">Generation of functional eyes from pluripotent cells.</a> PLoS Biol. 7 (8), (2009).</li><li>Choi, R. Y., 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=Cone+degeneration+following+rod+ablation+in+a+reversible+model+of+retinal+degeneration.">Cone degeneration following rod ablation in a reversible model of retinal degeneration.</a> Invest Ophthalmol Vis Sci. 52 (1), 364-373 (2011).</li><li>Viczian, A. S., Zuber, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+determination+using+the+animal+cap+transplant+(ACT)+assay+in+Xenopus+laevis.">Tissue determination using the animal cap transplant (ACT) assay in Xenopus laevis.</a> J Vis Exp. 16 (39), (2010).</li><li>Nieuwkoop, P. D., Faber, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Normal table of Xenopus laevis (Daudin) : a systematical and chronological survey of the development from the fertilized egg till the end of metamorphosis. , (1994).</li><li>Blackiston, D., Shomrat, T., Nicolas, C. L., Granata, C., Levin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+second-generation+device+for+automated+training+and+quantitative+behavior+analyses+of+molecularly-tractable+model+organisms.">A second-generation device for automated training and quantitative behavior analyses of molecularly-tractable model organisms.</a> PLoS One. 5 (12), (2010).</li><li>Rosemberg, D. B., 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=Differences+in+spatio-temporal+behavior+of+zebrafish+in+the+open+tank+paradigm+after+a+short-period+confinement+into+dark+and+bright+environments.">Differences in spatio-temporal behavior of zebrafish in the open tank paradigm after a short-period confinement into dark and bright environments.</a> PLoS One. 6 (5), (2011).</li><li>Dong, W., 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=Visual+Avoidance+in+Xenopus+Tadpoles+is+Correlated+With+the+Maturation+of+Visual+Responses+in+the+Optic+Tectum.">Visual Avoidance in Xenopus Tadpoles is Correlated With the Maturation of Visual Responses in the Optic Tectum.</a> J Neurophysiol. 101 (2), 803-815 (2009).</li><li>Lan, L., 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=Noggin+Elicits+Retinal+Fate+In+Xenopus+Animal+Cap+Embryonic+Stem+Cells.">Noggin Elicits Retinal Fate In Xenopus Animal Cap Embryonic Stem Cells.</a> Stem Cells. 27 (9), 2146-2152 (2009).</li><li>De Robertis, E. M., Kuroda, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dorsal-ventral+patterning+and+neural+induction+in+Xenopus+embryos.">Dorsal-ventral patterning and neural induction in Xenopus embryos.</a> Annu Rev Cell Dev Biol. 20, 285-308 (2004).</li></ol>

The authors have nothing to disclose.

Riportiamo qui un semplice test comportamentale visione-guida che può essere facilmente eseguita in meno di una settimana da personale di laboratorio minimamente addestrato. Mentre altri test richiedono attrezzature specializzate e competenze in comportamento animale, questo test permette un rapido test per determinare la funzione visiva. Un altro test comportamentale, il saggio evitare di Visual, è stato sviluppato per determinare come la Tectum contribuisce alla percezione visiva in Xenopus 10. Q...

Xenopus laevis sono stati utilizzati come organismo modello per studiare la formazione dell&#39;occhio. Gli occhi si sviluppano rapidamente, crescita verso la maturità in meno di una settimana per i geni di prova o percorsi che hanno un effetto sullo sviluppo visivo e la funzione. Per testare funzione visiva, la risposta optocinetico e optomotor è stato usato in zebrafish e girini Xenopus rispettivamente 1,2. Perché gli occhi dei girini di Xenopus sono relativamente più piccolo di zebrafish, questo test richiede l&#39;uso di attrezzature specializzate e personale addestrato per rilevare la coda-flip e movimenti oculari comportamento sottile in Xenopus. Un comportamento più robusto in Xenopus è la preferenza per il nuoto in un serbatoio con uno sfondo bianco, che viene qui descritto 3. Quando si posiziona un girino in mezzo serbatoio nero / mezzo bianco, il girino pre-metamorfica nuota rapidamente al lato bianco del serbatoio. Abbiamo già usato questo test per determinare se pluripotenti cellule derivategli occhi erano funzionali 4. Qui riportiamo una versione dettagliata di questo saggio, che può essere utilizzato per testare la funzione visiva di premetamorphic girini Xenopus. Questo test è più semplice del saggio risposta optomotor, dal momento che richiede solo una videocamera montata digitale, software fotocamera digitale e dotazione standard trovata nella maggior parte dei laboratori di Xenopus. Inoltre, la risposta registrata richiede alcuna formazione specifica ai risultati ottenuti. I nostri risultati rappresentativi mostrano che lo stesso gruppo di girini, che hanno subito doppio assotomia retinica, nuotano attorno al serbatoio. Abbiamo anche incluso i risultati del test comportamento di un girino rappresentante, mostrando come un occhio può essere testato per la risposta visiva. Un foglio di lavoro è stato incluso in modo che i numeri acquisiti durante il dosaggio possono essere inseriti e analizzati. Questo foglio può essere utilizzato per determinare se i girini testati hanno una risposta visiva.

<table border="0" cellpadding="0" cellspacing="0" width="654">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">1/2-gal. Flex-Tank with Cover</td>
			<td style="width:95px;">eNasco</td>
			<td style="width:119px;">SB19271M</td>
			<td style="width:225px;">size: 5-3/8&#34; x 7&#34; x 3-3/4&#34;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Black electrical tape</td>
			<td style="width:95px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">White tissue paper</td>
			<td style="width:95px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Large Inoculating Turntable</td>
			<td style="width:95px;">VWR</td>
			<td style="width:119px;">50809-022</td>
			<td>size: Dia 114.3 x&#160; H 76.2 mm (4 1/2&#160; x&#160; 3&#34;)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Durasorb Underpad</td>
			<td style="width:95px;">VWR</td>
			<td style="width:119px;">82004-836</td>
			<td>size: 43.2 x 60.1 cm (17 x 24&#34;)</td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:216px;">Kim wipe</td>
			<td style="width:95px;">Krackeler Scientific, Inc.</td>
			<td style="width:119px;">1945-34155-CS</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Standard Tripod</td>
			<td style="width:95px;"></td>
			<td style="width:119px;">various</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">iSight camera or webcam</td>
			<td style="width:95px;">Apple</td>
			<td style="width:119px;">M8817LL/A</td>
			<td>Good for larger tadpoles but small ones are difficult to see</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Portable computer</td>
			<td style="width:95px;">Apple/PC</td>
			<td style="width:119px;">various</td>
			<td>We used a 13&#34; MacBook, 2 GHz Intel Core 2 Duo running MacOSX Lion 10.7.5</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MiniDV Handycam Camcorder</td>
			<td style="width:95px;">SONY</td>
			<td style="width:119px;">DCR-HC42</td>
			<td>Connected by firewire to the computer with a 6-conductor and 4-conductor alpha FireWire 400&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Handycam Station</td>
			<td style="width:95px;">SONY</td>
			<td style="width:119px;">DCRA-C121</td>
			<td>This can be used for connecting firewire to camera</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">QuickTime Player software</td>
			<td style="width:95px;">Quicktime</td>
			<td style="width:119px;">Version 10.1</td>
			<td></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">26 Gauge Needle (5/8&#34; length)</td>
			<td style="width:95px;">VWR</td>
			<td style="width:119px;">BD305115</td>
			<td></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:216px;">Dumont #5 Forceps Biology</td>
			<td style="width:95px;">Fine Science Tools</td>
			<td style="width:119px;">11295-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:95px;"></td>
			<td style="width:119px;"></td>
			<td style="width:225px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:216px;">Disposables</td>
			<td style="width:95px;"></td>
			<td style="width:119px;"></td>
			<td style="width:225px;"></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">Gentamicin Sulfate [50 mg/ml]</td>
			<td style="width:95px;">Fisher Scientific</td>
			<td style="width:119px;">17-528Z</td>
			<td>Stored at room temperature</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">Sylgard 184 Silicone Elastomer</td>
			<td style="width:95px;">Fisher Scientific</td>
			<td style="width:119px;">NC9644388</td>
			<td></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:216px;">Instant Ocean</td>
			<td style="width:95px;">Doctors Foster and Smith</td>
			<td style="width:119px;">CD-116528</td>
			<td>Stock solution = 100 g/L stored at room temperature</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">Sodium phosphate dibasic</td>
			<td style="width:95px;">Sigma Aldrich</td>
			<td style="width:119px;">S0876</td>
			<td>Stock solution = 0.4 M stored at room temperature</td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:216px;">Tricaine (Ethyl-3-aminobenzoate methanesulfonate salt)</td>
			<td style="width:95px;">Sigma Aldrich</td>
			<td style="width:119px;">A5040</td>
			<td>Stock solution = 10% stored at -20&#730;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">In vitro fertilized embryos</td>
			<td style="width:95px;">eNasco</td>
			<td style="width:119px;">LM00490MX</td>
			<td>100 embryos/unit</td>
		</tr>
	</tbody>
</table>

a simple behavioral assay for testing visual function in xenopus laevis

Misurazione della funzione visiva nei girini di rana, Xenopus laevis, consente lo screening per la cecità di animali vivi. La risposta optocinetico è una visione-based, un comportamento riflessivo che è stato osservato in tutti i vertebrati esaminati. Occhi girino sono piccole quindi la risposta vibrazione coda è stato usato come misura alternativa, che richiede un tecnico addestrato per registrare la risposta sottile. Abbiamo sviluppato un saggio comportamento alternativo basato sul fatto che girini preferiscono nuotare sul lato bianco di un serbatoio quando posto in una vasca con lati sia in bianco e nero. Il saggio qui presentato è un poco costoso, semplice alternativa che crea una risposta che può essere facilmente misurata. L&#39;installazione consiste in un cavalletto, webcam e serbatoi di prova nidificati, facilmente reperibili nella maggior parte dei laboratori di Xenopus. Questo articolo include un filmato che mostra il comportamento dei girini, prima e dopo aver tagliato il nervo ottico. Al fine di testare la funzione di un occhio, includiamo anche rappresentantirisultati rappresentative di un girino in cui ogni occhio ha subito assotomia retinica in giorni consecutivi. Studi futuri potrebbero sviluppare una versione automatizzata di questo test per verificare la visione di molti girini in una volta.

I rapporti precedenti hanno dimostrato che premetamorphic girini Xenopus preferiscono nuotare sul lato bianco di un / serbatoio bianco e nero chiamato questo test, sullo sfondo Preferenza colore Assay 3 Abbiamo modificato questo test per testare la funzione visiva di entrambi gli occhi di girini in meno di una settimana. In questo modo, i loro occhi possono essere raccolti per l&#39;esame istologico. Mostriamo qui come la risposta è dovuta a stimoli visivi. In Mo...

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A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

Xenopus laevis girini preferiscono nuotare sul lato bianco di un / serbatoio bianco nero. Questo comportamento è guidato dalla loro visione. Sulla base di questo comportamento, vi presentiamo un semplice test per testare la funzione visiva dei girini.

Un test comportamentale semplice for Testing Funzione visiva in<em&gt; Xenopus laevis</em

Measurement of the visual function in the tadpoles of the frog, Xenopus laevis, allows screening for blindness in live animals. The optokinetic response ...

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JoVE Journal

Neuroscience

A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

9.7K Views.  Center for Vision Research, SUNY Eye Institute, Upstate Medical University.  Xenopus laevis girini preferiscono nuotare sul lato bianco di un / serbatoio bianco nero. Questo comportamento è guidato dalla loro visione. Sulla base di questo comportamento, vi presentiamo un semplice test per testare la funzione visiva dei girini. 

Video: A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

The Vermicelli and Capellini Handling Tests: Simple quantitative measures of dexterous forepaw function in rats and mice

Previous characterizations of rodent eating behavior have revealed that they use coordinated forepaw movements to manipulate food pieces. We have extended upon this work to develop a simple quantitative measure of forepaw dexterity that is sensitive to lateralized impairments and age-dependent changes. Rodents learn skillful forepaw and digit movements to manage thin pasta pieces, which they eagerly consume. We have previously described methods for quantifying vermicelli handling in rats and showed that the measures are very sensitive to forelimb impairments resulting from unilateral ischemic lesions, middle cerebral artery occlusions and unilateral striatal dopamine depletion [Allred, R.P., Adkins, D.L., Woodlee, M.T., Husbands, L.C., Maldonado M.A., Kane, J.R., Schallert, T. &amp; Jones, T.A. The Vermicelli Handling Test: a simple quantitative measure of dexterous forepaw function in rats. J. Neurosci. Methods 170, 229-244 (2008)]. Here we present a more detailed protocol for this test in rats and compare it with a newly developed version for mice, the Capellini Handling Test. Rats and mice are videotaped while handling short lengths of uncooked vermicelli or capellini pasta, respectively, with a camera positioned to optimize the view of paw movements. Slow motion video playback allows for the identification of forepaw adjustments, defined as any distinct removal and replacement of the paw, or of any number of digits, on the pasta piece after eating commences. Forepaw adjustments per piece are averaged over trials per each testing session. Repeated testing permits sensitive quantitative analysis of changes in forepaw dexterity over time. Protocols for pre-testing habituation and handling practice, as well as procedures for characterizing atypical handling patterns, are described. Because rats and mice perform the pasta handling tests slightly differently, species-specific differences in administration and scoring of these tests are highlighted. All animal use was in accordance with protocols approved by the University of Texas at Austin Animal Care and Use Committee.

The Vermicelli and Capellini Handling Tests of forepaw dexterity take advantage of the natural inclination of rodents to manipulate food items using skillful forepaw and digit movements. Animals are videotaped while handling short strands of uncooked dry pasta. Slow motion video playback allows for the quantification of forepaw adjustments.

I vermicelli e test Manipolazione Capellini: Semplici misure quantitative della funzione zampe anteriori abile nel ratto e nel topo

Previous characterizations of rodent eating behavior have revealed that they use coordinated forepaw movements to manipulate food pieces. We have extended ...

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Neuroscienze

A General Method for Evaluating Incubation of Sucrose Craving in Rats

For someone on a food-restricted diet, food craving in response to food-paired cues may serve as a key behavioral transition point between abstinence and relapse to food taking 1. Food craving conceptualized in this way is akin to drug craving in response to drug-paired cues. A rich literature has been developed around understanding the behavioral and neurobiological determinants of drug craving; we and others have been focusing recently on translating techniques from basic addiction research to better understand addiction-like behaviors related to food 2-4.
As done in previous studies of drug craving, we examine sucrose craving behavior by utilizing a rat model of relapse. In this model, rats self-administer either drug or food in sessions over several days. In a session, lever responding delivers the reward along with a tone+light stimulus. Craving behavior is then operationally defined as responding in a subsequent session where the reward is not available. Rats will reliably respond for the tone+light stimulus, likely due to its acquired conditioned reinforcing properties 5. This behavior is sometimes referred to as sucrose seeking or cue reactivity. In the present discussion we will use the term "sucrose craving" to subsume both of these constructs.
In the past decade, we have focused on how the length of time following reward self-administration influences reward craving. Interestingly, rats increase responding for the reward-paired cue over the course of several weeks of a period of forced-abstinence. This "incubation of craving" is observed in rats that have self-administered either food or drugs of abuse 4,6. This time-dependent increase in craving we have identified in the animal model may have great potential relevance to human drug and food addiction behaviors.
Here we present a protocol for assessing incubation of sucrose craving in rats. Variants of the procedure will be indicated where craving is assessed as responding for a discrete sucrose-paired cue following extinction of lever pressing within the sucrose self-administration context (Extinction without cues) or as responding for sucrose-paired cues in a general extinction context (Extinction with cues).

Responding for food or drug-paired cues increases over the course of a period of abstinence and this may relate to an increased susceptibility to relapse behaviors. Here we detail a procedure for evaluating this "incubation of craving" in rats that have self-administered sucrose.

Un metodo generale per la valutazione di incubazione della brama di saccarosio in ratti

For someone on a food-restricted diet, food craving in response to food-paired cues may serve as a key behavioral transition point between abstinence and ...

Neural Explant Cultures from Xenopus laevis

The complex process of axon guidance is largely driven by the growth cone, which is the dynamic motile structure at the tip of the growing axon. During axon outgrowth, the growth cone must integrate multiple sources of guidance cue information to modulate its cytoskeleton in order to propel the growth cone forward and accurately navigate to find its specific targets1. How this integration occurs at the cytoskeletal level is still emerging, and examination of cytoskeletal protein and effector dynamics within the growth cone can allow the elucidation of these mechanisms. Xenopus laevis growth cones are large enough (10-30 microns in diameter) to perform high-resolution live imaging of cytoskeletal dynamics (e.g.2-4 ) and are easy to isolate and manipulate in a lab setting compared to other vertebrates. The frog is a classic model system for developmental neurobiology studies, and important early insights into growth cone microtubule dynamics were initially found using this system5-7 . In this method8, eggs are collected and fertilized in vitro, injected with RNA encoding fluorescently tagged cytoskeletal fusion proteins or other constructs to manipulate gene expression, and then allowed to develop to the neural tube stage. Neural tubes are isolated by dissection and then are cultured, and growth cones on outgrowing neurites are imaged. In this article, we describe how to perform this method, the goal of which is to culture Xenopus laevis growth cones for subsequent high-resolution image analysis. While we provide the example of +TIP fusion protein EB1-GFP, this method can be applied to any number of proteins to elucidate their behaviors within the growth cone.

Neural Explant Cultures from Xenopus laevis

Culturing neural explants from dissected Xenopus laevis embryos that express fluorescent fusion proteins allows for imaging of growth cone cytoskeletal dynamics.

Culture Explant neurali di<em&gt; Xenopus laevis</em

The complex process of axon guidance is largely driven by the growth cone, which is the dynamic motile structure at the tip of the growing axon. During ...

Dissection, Culture, and Analysis of Xenopus laevis Embryonic Retinal Tissue

The process by which the anterior region of the neural plate gives rise to the vertebrate retina continues to be a major focus of both clinical and basic research. In addition to the obvious medical relevance for understanding and treating retinal disease, the development of the vertebrate retina continues to serve as an important and elegant model system for understanding neuronal cell type determination and differentiation1-16. The neural retina consists of six discrete cell types (ganglion, amacrine, horizontal, photoreceptors, bipolar cells, and M&uuml;ller glial cells) arranged in stereotypical layers, a pattern that is largely conserved among all vertebrates 12,14-18.
While studying the retina in the intact developing embryo is clearly required for understanding how this complex organ develops from a protrusion of the forebrain into a layered structure, there are many questions that benefit from employing approaches using primary cell culture of presumptive retinal cells 7,19-23. For example, analyzing cells from tissues removed and dissociated at different stages allows one to discern the state of specification of individual cells at different developmental stages, that is, the fate of the cells in the absence of interactions with neighboring tissues 8,19-22,24-33. Primary cell culture also allows the investigator to treat the culture with specific reagents and analyze the results on a single cell level 5,8,21,24,27-30,33-39. Xenopus laevis, a classic model system for the study of early neural development 19,27,29,31-32,40-42, serves as a particularly suitable system for retinal primary cell culture 10,38,43-45.
Presumptive retinal tissue is accessible from the earliest stages of development, immediately following neural induction 25,38,43. In addition, given that each cell in the embryo contains a supply of yolk, retinal cells can be cultured in a very simple defined media consisting of a buffered salt solution, thus removing the confounding effects of incubation or other sera-based products 10,24,44-45.
However, the isolation of the retinal tissue from surrounding tissues and the subsequent processing is challenging. Here, we present a method for the dissection and dissociation of retinal cells in Xenopus laevis that will be used to prepare primary cell cultures that will, in turn, be analyzed for calcium activity and gene expression at the resolution of single cells. While the topic presented in this paper is the analysis of spontaneous calcium transients, the technique is broadly applicable to a wide array of research questions and approaches (Figure 1).

Dissection, Culture, and Analysis of Xenopus laevis Embryonic Retinal Tissue

Xenopus laevis provides an ideal model system for studying cell fate specification and physiological function of individual retinal cells in primary cell culture. Here we present a technique for dissecting retinal tissues and generating primary cell cultures that are imaged for calcium activity and analyzed by in situ hybridization.

Dissezione, Cultura, e analisi di<em&gt; Xenopus laevis</em&gt; Tessuto embrionale della retina

The process by which  the anterior region of the neural plate gives rise to the vertebrate retina  continues to be a major focus of both clinical and ...

Hippocampal Insulin Microinjection and In vivo Microdialysis During Spatial Memory Testing

Glucose metabolism is a useful marker for local neural activity, forming the basis of methods such as 2-deoxyglucose and functional magnetic resonance imaging. However, use of such methods in animal models requires anesthesia and hence both alters the brain state and prevents behavioral measures. An alternative method is the use of in vivo microdialysis to take continuous measurement of brain extracellular fluid concentrations of glucose, lactate, and related metabolites in awake, unrestrained animals. This technique is especially useful when combined with tasks designed to rely on specific brain regions and/or acute pharmacological manipulation; for example, hippocampal measurements during a spatial working memory task (spontaneous alternation) show a dip in extracellular glucose and rise in lactate that are suggestive of enhanced glycolysis1-3,4-5, and intrahippocampal insulin administration both improves memory and increases hippocampal glycolysis6. Substances such as insulin can be delivered to the hippocampus via the same microdialysis probe used to measure metabolites. The use of spontaneous alternation as a measure of hippocampal function is designed to avoid any confound from stressful motivators (e.g. footshock), restraint, or rewards (e.g. food), all of which can alter both task performance and metabolism; this task also provides a measure of motor activity that permits control for nonspecific effects of treatment. Combined, these methods permit direct measurement of the neurochemical and metabolic variables regulating behavior.

Hippocampal Insulin Microinjection and In vivo Microdialysis During Spatial Memory Testing

Modulation of hippocampally-dependent spatial working memory by direct intrahippocampal microinjection, accompanied and followed by in vivo microdialysis for metabolites in conscious, behaving animals.

Insulina Microiniezione ippocampale e<em&gt; In vivo</emMicrodialisi&gt; Durante il test di memoria spaziale

Glucose metabolism is a useful marker for local neural activity, forming the basis of methods such as 2-deoxyglucose and functional magnetic resonance ...

A Lightweight, Headphones-based System for Manipulating Auditory Feedback in Songbirds

Experimental manipulations of sensory feedback during complex behavior have provided valuable insights into the computations underlying motor control and sensorimotor plasticity1. Consistent sensory perturbations result in compensatory changes in motor output, reflecting changes in feedforward motor control that reduce the experienced feedback error. By quantifying how different sensory feedback errors affect human behavior, prior studies have explored how visual signals are used to recalibrate arm movements2,3 and auditory feedback is used to modify speech production4-7. The strength of this approach rests on the ability to mimic naturalistic errors in behavior, allowing the experimenter to observe how experienced errors in production are used to recalibrate motor output.
Songbirds provide an excellent animal model for investigating the neural basis of sensorimotor control and plasticity8,9. The songbird brain provides a well-defined circuit in which the areas necessary for song learning are spatially separated from those required for song production, and neural recording and lesion studies have made significant advances in understanding how different brain areas contribute to vocal behavior9-12. However, the lack of a naturalistic error-correction paradigm - in which a known acoustic parameter is perturbed by the experimenter and then corrected by the songbird - has made it difficult to understand the computations underlying vocal learning or how different elements of the neural circuit contribute to the correction of vocal errors13.
The technique described here gives the experimenter precise control over auditory feedback errors in singing birds, allowing the introduction of arbitrary sensory errors that can be used to drive vocal learning. Online sound-processing equipment is used to introduce a known perturbation to the acoustics of song, and a miniaturized headphones apparatus is used to replace a songbird's natural auditory feedback with the perturbed signal in real time. We have used this paradigm to perturb the fundamental frequency (pitch) of auditory feedback in adult songbirds, providing the first demonstration that adult birds maintain vocal performance using error correction14. The present protocol can be used to implement a wide range of sensory feedback perturbations (including but not limited to pitch shifts) to investigate the computational and neurophysiological basis of vocal learning.

We describe the design and assembly of miniaturized headphones suitable for replacing a songbird&#x2019;s natural auditory feedback with a manipulated acoustic signal. Online sound processing hardware is used to manipulate song output, introduce real-time errors in auditory feedback via the headphones, and drive vocal motor learning.

Un leggero, Cuffie-based per la gestione di sistema feedback uditivo in Songbirds

Experimental manipulations of sensory feedback during complex behavior have provided valuable insights into the computations underlying motor control and ...

Simultaneous ex vivo Functional Testing of Two Retinas by in vivo Electroretinogram System

An In vivo electroretinogram (ERG) signal is composed of several overlapping components originating from different retinal cell types, as well as noise from extra-retinal sources. Ex vivo ERG provides an efficient method to dissect the function of retinal cells directly from an intact isolated retina of animals or donor eyes. In addition, ex vivo ERG can be used to test the efficacy and safety of potential therapeutic agents on retina tissue from animals or humans. We show here how commercially available in vivo ERG systems can be used to conduct ex vivo ERG recordings from isolated mouse retinas. We combine the light stimulation, electronic and heating units of a standard in vivo system with custom-designed specimen holder, gravity-controlled perfusion system and electromagnetic noise shielding to record low-noise ex vivo ERG signals simultaneously from two retinas with the acquisition software included in commercial in vivo systems. Further, we demonstrate how to use this method in combination with pharmacological treatments that remove specific ERG components in order to dissect the function of certain retinal cell types.

Simultaneous ex vivo Functional Testing of Two Retinas by in vivo Electroretinogram System

Ex vivo ERG can be used to record electrical activity of retinal cells directly from isolated intact retinas of animals or humans. We demonstrate here how common in vivo ERG systems can be adapted for ex vivo ERG recordings in order to dissect the electrical activity of retinal cells.

Simultaneo<em&gt; Ex vivo</em&gt; Test funzionale di due retine per<em&gt; In vivo</em&gt; Sistema Elettroretinogramma

An In vivo electroretinogram (ERG) signal is composed of several overlapping components originating from different retinal cell types, as well as noise ...

A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster

Because of the structural and functional homology to the hair cells of the mammalian inner ear, the neurons that innervate the Drosophila external sense organs provide an excellent model system for the study of mechanosensation. This protocol describes a simple touch behavior in fruit flies which can be used to identify mutations that interfere with mechanosensation. The tactile stimulation of a macrochaete bristle on the thorax of flies elicits a grooming reflex from either the first or third leg. Mutations that interfere with mechanotransduction (such as NOMPC), or with other aspects of the reflex arc, can inhibit the grooming response. A traditional screen of adult behaviors would have missed mutants that have essential roles during development. Instead, this protocol combines the touch screen with mosaic analysis with a repressible cell marker (MARCM) to allow for only limited regions of homozygous mutant cells to be generated and marked by the expression of green fluorescent protein (GFP). By testing MARCM clones for abnormal behavioral responses, it is possible to screen a collection of lethal p-element mutations to search for new genes involved in mechanosensation that would have been missed by more traditional methods.

A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster

In order to identify novel mutations affecting mechanosensation, we designed an assay that measures the behavioral response to tactile stimulation of fly bristles in mutant clones generated by the MARCM method. The combination of techniques allows for the identification of mechanosensitive mutations that would otherwise be lethal.

Un test comportamentale per Mechanosensation di cloni in marcm-based<em&gt; Drosophila melanogaster</em

Because of the structural and functional homology to the hair cells of the mammalian inner ear, the neurons that innervate the Drosophila external sense ...

Recording Temperature-induced Neuronal Activity through Monitoring Calcium Changes in the Olfactory Bulb of Xenopus laevis

The olfactory system, specialized in the detection, integration and processing of chemical molecules is likely the most thoroughly studied sensory system. However, there is piling evidence that olfaction is not solely limited to chemical sensitivity, but also includes temperature sensitivity. Premetamorphic Xenopus laevis are translucent animals, with protruding nasal cavities deprived of the cribriform plate separating the nose and the olfactory bulb. These characteristics make them well suited for studying olfaction, and particularly thermosensitivity. The present article describes the complete procedure for measuring temperature responses in the olfactory bulb of X. laevis larvae. Firstly, the electroporation of olfactory receptor neurons (ORNs) is performed with spectrally distinct dyes loaded into the nasal cavities in order to stain their axon terminals in the bulbar neuropil. The differential staining between left and right receptor neurons serves to identify the &#947;-glomerulus as the only structure innervated by contralateral presynaptic afferents. Secondly, the electroporation is combined with focal bolus loading in the olfactory bulb in order to stain mitral cells and their dendrites. The 3D brain volume is then scanned under line-illumination microscopy for the acquisition of fast calcium imaging data while small temperature drops are induced at the olfactory epithelium. Lastly, the post-acquisition analysis allows the morphological reconstruction of the thermosensitive network comprising the &#947;-glomerulus and its innervating mitral cells, based on specific temperature-induced Ca2+ traces. Using chemical odorants as stimuli in addition to temperature jumps enables the comparison between thermosensitive and chemosensitive networks in the olfactory bulb.

Recording Temperature-induced Neuronal Activity through Monitoring Calcium Changes in the Olfactory Bulb of Xenopus laevis

Here we describe a protocol for measuring and analyzing temperature responses in the olfactory bulb of Xenopus laevis. Olfactory receptor neurons and mitral cells are differentially stained, after which calcium changes are recorded, reflecting a sensitivity of some neural networks in the bulb to temperature drops induced at the nose.

Registrazione neuronale attività Temperatura indotta attraverso il monitoraggio dei cambiamenti di calcio nel bulbo olfattivo di<em&gt; Laevis Xenopus</em

The olfactory system, specialized in the detection, integration and processing of chemical molecules is likely the most thoroughly studied sensory system. ...

Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons

The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic tectum, is a popular model to study how neural circuits self-assemble. The ability to carry out whole cell patch clamp recordings from tectal neurons and to record RGC-evoked responses, either in vivo or using a whole brain preparation, has generated a large body of high-resolution data about the mechanisms underlying normal, and abnormal, circuit formation and function. Here we describe how to perform the in vivo preparation, the original whole brain preparation, and a more recently developed horizontal brain slice preparation for obtaining whole cell patch clamp recordings from tectal neurons. Each preparation has unique experimental advantages. The in vivo preparation enables the recording of the direct response of tectal neurons to visual stimuli projected onto the eye. The whole brain preparation allows for the RGC axons to be activated in a highly controlled manner, and the horizontal brain slice preparation allows recording from across all layers of the tectum.

Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons

In this paper, we discuss three brain preparations used for whole cell patch clamp recording to study the retinotectal circuit of Xenopus laevis tadpoles. Each preparation, with its own specific advantages, contributes to the experimental tractability of the Xenopus tadpole as a model to study neural circuit function.

Preparazioni e protocolli per l'intera cella Patch Clamp registrazione dei neuroni Tectal Xenopus laevis

The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic ...