Este trabalho foi financiado por subvenções dos Institutos Nacionais de Saúde: EY015748, EY017964 (MEZ) e EY019517 (ASV). Este trabalho também foi apoiado pela Research para prevenir a cegueira irrestrito Grant ao Departamento de Oftalmologia e os Leões da Central de Nova York. Gostaríamos também de agradecer ao nosso técnico de animal, Matthew Mellini, pelo excelente cuidado dos animais e para intervindo para estrelar este vídeo.

Animal Care A Xenopus laevis girinos utilizados neste estudo foram cultivados, criados e tratados de acordo com procedimentos aprovados pelo Upstate Medical University IACUC eo Guia para o Cuidado e Uso de Animais de Laboratório. 1. Instalação Pré-comportamento: Os girinos <ol><li> Obter embriões de Xenopus fertilizados a partir de uma fonte disponível comercialmente ou fertilizar os oócitos in vitro, como descrito anteriormente 6. </li><li> Coloque blastula de embriões em estágio placa neural em 18 ˚ C em 60 milímetros placas de Petri contendo 0,1 X MMR [10 Modificado estoque solução (MMR) de Ringer de X Marc (10 mM MgCl2, KCl 20 mM, 20 mM CaCl2, 50 mM HEPES; NaCl 1 M; ajustado para pH 7,5, autoclavado e armazenado a temperatura ambiente)] com 50 ug / ml de antibiótico gentamicina. Mude 0,1 X MMR cada dia e remover quaisquer embriões mortos. </li><li> Uma vez que os embriões atingem Nieuwkoop e Faber fase ~ 27-30 julho, mude ªe embriões em 0,1 X MMR sem antibiótico para permitir o crescimento de bactérias do intestino. </li><li> Crescer os girinos até que atinjam a fase de alimentação (fase 45) e movê-los em 100 milímetros placas de Petri cheias de 0,1 X MMR. Alimentá-los urtiga sobrenadante pó todos os dias durante uma semana, mudando a 0,1 X MMR no dia de intervenção. </li><li> Depois de uma semana na 100 milímetros placa de Petri, mova animais para meia galão tanques cheios de água sapo [0,5 g / L oceano instantâneas e 2 mM de sódio dibásico (Na 2 HPO 4: mw 141,96) pH 6,8]. Alimente-os como no passo 2.4, mas mudar a água apenas 2-3 vezes por semana, quando a água está turva. Manter os animais em um 12 horas light/12 ciclo claro-escuro com as luzes de ligar às 6 da manhã. </li><li> Coloque o tanque de meio litro com os assuntos de teste em uma superfície branca, como um resguardo bancada do laboratório, pelo menos 12 horas O / N, antes do teste. </li><li> Girinos de teste nas fases 45 a 50, tal como descrito no passo 3 abaixo. </li></ol> . 2 Configuração Pré-comportamento: Equipment <ol><li> Separe uma área do laboratório para o ensaio de comportamento. Ele deve estar em uma área tranquila, de baixo tráfego, com iluminação fluorescente padrão. </li><li> Prepare os tanques de teste para os animais. Os aninhados, tanques de teste de meio-litro são compostos de duas partes: um tanque interno que vai segurar a água e girinos; e um tanque exterior com o estímulo visual. <ol><li> Para o tanque interno, fazer uma pequena marca nos cantos externos com um Sharpie, a 5 cm do fundo; esta é a linha de água (Figura 1A, linha pontilhada verde). </li><li> Além disso, para o tanque interno, preencha os divets no tanque (nos cantos e no centro) com um composto inerte, como Sylgard elastômero. NOTA: Os girinos permanecerá nestas áreas se não forem preenchidos </li><li> Para o tanque exterior, cobrem exactamente a metade do lado de fora de um tanque com uma fita isolante preto e a outra metade com o tecido de papel branco Figura 1B. </li></ol></li><li> Colocar os tanques nainoculando plataforma giratória. </li><li> Configuração da webcam / tripé para que ele está acima dos tanques de teste. Ajustar a câmara para permitir a visualização de área de teste, tal como mostrado na Figura 1C. </li><li> Conecte a webcam ao computador com o software QuickTime Player instalado 5. Ligue a câmera. No QuickTime Player, em Arquivo, selecione &#39;New Gravação de filme. &quot; A configuração do ensaio de comportamento será visível no computador imediatamente. </li><li> Estenda um pano de algodão leve ao longo de toda a instalação para reduzir a estímulos externos que podem afetar o comportamento de girinos, bem como, reduzir a luz refletida na superfície da água. </li><li> Certifique-se que a luminosidade no âmbito das medidas de pano entre 35-50 cd / m 2. </li></ol> 3. Assay Comportamento <ol><li> Encha o tanque de provas interior para a marca de 5 cm de água feita no passo 1.2.1 com água sapo. </li><li> Usando uma pequena rede, mova suavemente o animal para dentro do tanque de teste interno. </li><li> Abrir QuickTime software no computador e, usando o tanque exterior como um guia, certifique-se de que a câmera é capaz de visualizar e registrar a área de testes. </li><li> Escreva o nome dos animais, data e hora em um pedaço de papel e gravar com a câmera. </li><li> Coloque o tanque de teste para o tanque exterior com o lado negro do tanque para a direita Figura 2. </li><li> Comece a gravar o filme imediatamente depois de organizar o tanque e ajustar o temporizador para 2 min. </li><li> Quando os beeps temporizador, remova o tanque de teste interno, gire o tanque exterior de 180 ° e coloque o tanque de teste interno dentro do tanque externo. Inicie o cronômetro. Nota: o lado negro deve ser agora no outro lado. </li><li> Repita o passo 3.7, mais oito vezes para um total de dez ensaios. Use a Figura 2 como um guia, riscando cada julgamento. </li><li> Repetir o ensaio de comportamento em dois dias separados. </li></ol> 4. Retinal axotomia <ol><li> Coloque o animal em 0,02% tricaina até que eles não respondempara uma pitada de cauda com um # 3 fórceps. </li><li> Derreta 1% de agarose em 0,1 X MMR e, em seguida, adicionar a uma 60 milímetros placa de Petri. Uma vez arrefecido, fazer uma pequena torrão rectangular na agarose e adicionar o girino para o torrão com um pouco de 0,02% tricaína, de modo que o animal está parcialmente submerso no líquido. </li><li> Perfurar a pele a um ângulo de 45 graus atrás região dorsal do olho com uma agulha 25 G, enquanto que preparando o animal contra uma pinça sobre o lado oposto. </li><li> Tomando cuidado para não cortar a veia, que fica próximo ao nervo óptico, cuidadosamente chegar no buraco com # 5 fórceps, cortar o nervo óptico e lançá-lo para fora do caminho. Se houver hemorragia grave devido a acidentalmente cortando a artéria, em seguida, coloque rapidamente o animal em 2% tricaina a eutanásia. CUIDADO: solução tricaina 2% pode causar dormência em seres humanos. Esta solução deve ser manuseado com luvas. </li><li> Para recuperar o animal após a cirurgia, coloca animal em placa de 100 mm de Petri com 0,7 X MMR e 50 ug / ml de gentamicina, durante 20 min. Next, transferência de girino para tanque de recuperação com água sapo. Deixe descansar animais O / N. </li><li> Na manhã seguinte, o teste da função visual, como descrito acima (etapas 3,1-3,9). </li></ol> 5. Analisar os Resultados <ol><li> Após os ensaios de terminado, medir a quantidade de tempo que o girino permanece sobre o lado negro do tanque. <ol><li> Visualizar manualmente os vídeos usando software que exibe o tempo e permite pausas frequentes. Olhe para o tempo de exibição de vídeo. Faça-se o início do ensaio de dois minutos, o qual é, quando o tanque interior aninha com sucesso dentro do tanque exterior e é elevado ao quadrado em vista da câmara. </li><li> Utilizar a posição dos olhos do girino para definir qual dos lados do tanque, os animais são em natação. Definir atravessar de um lado do tanque para o outro apenas quando ambos os olhos ter atravessado a linha de preto / branco. </li></ol></li><li> Anote o início eo fim de cada intervalo (em segundos) que o animal passa do lado negro. Faça uma pausa e reenrole o vídeo para garantir a precisão. Total do sec dentro de cada julgamento. </li><li> Entrada esses números na planilha Comportamento anexado. A planilha irá calcular a proporção de tempo que o animal passou do lado branco, subtraindo o tempo gasto com o lado negro do tanque do total de seg julgamento e dividir por 120 o tempo total em segundos [(120 - total gasto em segundos o lado negro) / 120 seg]. As médias da planilha esta relação sobre todas as 10 tentativas. </li><li> Use T-teste de um aluno, emparelhado, distribuição bicaudal para determinar se as provas entre os dias são significativas (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.

Relatamos aqui um ensaio comportamental guiada pela visão simples que pode ser facilmente realizado em menos de uma semana pelo pessoal de laboratório minimamente treinados. Enquanto outros ensaios requerem equipamento especializado e experiência em comportamento animal, este ensaio permite um teste rápido para determinar a função visual. Outro ensaio comportamental, o ensaio de evitação visual, foi desenvolvida para determinar a forma como o tectum contribui para a percepção visual em Xenopus 10...

Xenopus laevis foram utilizados como um organismo modelo para estudar a formação do olho. Os olhos se desenvolvem rapidamente, crescendo para a maturidade em menos de uma semana para testar genes ou vias que têm um efeito sobre o desenvolvimento visual e função. Para testar a função visual, a resposta optocinéticos optomotor e tem sido usado em peixes-zebra e girinos de Xenopus, respectivamente, de 1,2. Porque os olhos de girinos de Xenopus são relativamente menores do que peixe-zebra, este ensaio requer o uso de equipamento especializado e pessoal treinado para detectar o comportamento sutil cauda-flip e olho-movimento em Xenopus. Um comportamento mais robusto em Xenopus é a preferência para nadar em um tanque com um fundo branco, que é aqui descrito 3. Ao colocar um girino em um tanque preto / meia branca meia, o girino pré-metamórfica nada rapidamente para o lado branco do tanque. Nós anteriormente utilizado neste ensaio para determinar se o derivado de células pluripotentesolhos eram funcional 4. Aqui, apresentamos uma versão detalhada deste ensaio, que pode ser usado para testar a função visual de girinos de Xenopus premetamorphic. Este ensaio é mais simples do que o ensaio de resposta optomotor, uma vez que requer apenas uma câmara de vídeo montada digital, câmera digital e software de equipamentos padrão encontrado na maioria dos laboratórios de Xenopus. Além disso, a resposta registrada não requer nenhum treinamento especial para resultados tally. Nossos resultados representativos mostram que o mesmo grupo de girinos, tendo sofrido axotomia retina dupla, nadam aleatoriamente em torno do tanque. Também foram incluídos os resultados do ensaio de comportamento de um girino representativo, mostrando como um olho podem ser testados para a resposta visual. A folha de cálculo foi incluída de modo que os números adquiridos durante o ensaio pode ser inserido e analisados. Esta folha pode ser utilizado para determinar se os girinos testados têm uma resposta visual.

<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

Medição da função visual nos girinos do sapo, Xenopus laevis, permite a triagem para a cegueira de animais vivos. A resposta optocinéticos é, um comportamento reflexiva à base de visão que tem sido observada em todos os vertebrados testados. Girino olhos são pequenos para que a resposta da cauda da aleta foi usada como medida alternativa, o que requer um técnico treinado para registrar a resposta sutil. Foi desenvolvido um ensaio de comportamento alternativo, baseado no facto de que os girinos preferem nadar no lado branco do tanque, quando colocado num tanque com lados tanto a preto e branco. O ensaio aqui apresentado é uma alternativa de baixo custo, simples que cria uma resposta que pode ser facilmente medido. A instalação consiste em um tripé, webcam e tanques de teste aninhados, prontamente disponível na maioria dos laboratórios de Xenopus. Este artigo inclui um filme que mostra o comportamento de girinos, antes e depois do corte do nervo óptico. A fim de testar a função de um olho, também incluem represenresultados representativa de um girino em que cada olho sofreu axotomia da retina em dias consecutivos. Estudos futuros poderia desenvolver uma versão automatizada deste ensaio para testar a visão de muitos girinos de uma só vez.

Relatórios anteriores demonstraram que os girinos de Xenopus premetamorphic preferir nadar no lado branco de um tanque de preto / branco e chamou este ensaio, o Fundo Preferência de cor Ensaio 3 Mudamos este ensaio, a fim de testar a função visual de ambos os olhos de girinos em menos do que uma semana. Desta forma, os olhos podem ser recolhidos para exame histológico. Mostramos aqui como a resposta é devido a pistas visuais. No Movie 1, os girinos ...

Watch this Scientific Journal Video about A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis at JoVE.com

A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

Girinos de Xenopus laevis preferem nadar no lado branco de um tanque preto / branco. Este comportamento é guiado pela sua visão. Com base nesse comportamento, apresentamos um ensaio simples para testar a função visual de girinos.

Um Ensaio Comportamental simples para Teste de Função Visual em<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 ...

a-simple-behavioral-assay-for-testing-visual-function-xenopus

Research

JoVE Journal

Neuroscience

A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

9.7K visualizações.  Center for Vision Research, SUNY Eye Institute, Upstate Medical University.  Girinos de Xenopus laevis preferem nadar no lado branco de um tanque preto / branco. Este comportamento é guiado pela sua visão. Com base nesse comportamento, apresentamos um ensaio simples para testar a função visual de girinos. 

Vídeo: 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.

O Vermicelli e Testes Handling Capellini: Simple medidas quantitativas da função forepaw dexterous em ratos e camundongos

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

Neurociência

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.

Um método geral para a avaliação de Incubação de Craving Sacarose em Ratos

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.

Neurais culturas de explante de<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.

Dissecção, Cultura, Análise e de<em&gt; Xenopus laevis</em&gt; Tecido embrionário da 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.

Microinjeção insulina hipocampal e<em&gt; Em vivo</em&gt; Microdiálise Durante um teste de memória espacial

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.

Um leve, sistema de fones baseado para manipular feedback auditivo em 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.

Simultâneo<em&gt; Ex vivo</em&gt; Teste Funcional de Dois retinas por<em&gt; In vivo</em&gt; Sistema Eletrorretinograma

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.

Clones em um ensaio comportamental para Mechanosensation de MarcM baseada em<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.

Gravação induzida pela temperatura actividade neuronal através de monitoramento das alterações de cálcio no bulbo olfativo de<em&gt; Xenopus laevis</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.

Preparações e protocolos para toda célula Patch Clamp gravação de neurônios 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 ...