This work was partially supported by National Institute of Deafness and Other Communications Disorders Awards R03-DC-012125 to D. A. Llano and F31-DC-013501 to B. J. Slater as well as the Carver Foundation.
The authors would like to thank Jason MacLean and Matthew Banks for technical advice with calcium imaging.

Todos os procedimentos foram aprovados pelo Comitê de Uso e Cuidado Animal Institucional na Universidade de Illinois. Todos os animais foram alojados em instalações de cuidados de animais aprovados pela Associação Americana para Credenciamento de Laboratório Animal Care. Foi feito todos os esforços para minimizar o número de animais utilizados e reduzir o sofrimento em todas as fases do estudo. 1. Preparação e Remoção de cérebro de rato para Cortando <ol><li> Prepare-se para perfusão e fatia de incubação. <ol><li> Cerca de 30 minutos antes de cortar, preparar alta solução de corte de sacarose e de baixo aCSF cálcio para a incubação da fatia antes da gravação ou imagem. </li><li> Colocar para fora todas as ferramentas necessárias (grandes tesouras cegas finais, pequenas tesouras primavera, pinças anatômicas, grandes tesouras ou guilhotina, íris tesouras, joalheiros fórceps, seringa de 10 ml com agulha de 27G x 1/2 polegadas, pequeno pedaço de 1 cm x 2 cm de filtro papel, e uma pipeta Pasteur com ponta quebrada para sltransferência de gelo) para perfusão e corte, e preparar a bandeja de perfusão. </li><li> Configurar câmara com oxigenado aCSF incubação num banho de água 32 o C e um prato de cultura preenchido com solução de corte. </li></ol></li><li> Prepare corte palco para cortar. <ol><li> Corte um pequeno pedaço de agar a 3%, aproximadamente, 1 cm 3 para usar como um batente para o cérebro e 1,5 cm x 1,5 mm x 3 mm para uma colisão para ser utilizado para sustentar o IC. </li><li> Cole o batente traseiro para o palco com adesivo de cianoacrilato, bem como a saliência no lado direito do batente de tal modo que eles formam um ângulo de 80 °. </li></ol></li><li> Remover o cérebro. <ol><li> Profundamente anestesiar a p12-p20 (idealmente p14-18) mouse com cetamina 100 mg / kg e xylaxine 3 mg / kg (ou procedimento aprovado comitê de ética comparáveis). Nota: Confirme nível anestesia adequada através de falta de resposta aos pés pitada. À medida que o animal é brevemente sob anestesia, pomada oftálmica é desnecessária. </li><li> Usando sem cortetesoura acabar, expor a caixa torácica do apêndice xifóide até o pescoço. <ol><li> Encontre o apêndice xifóide, e faça um corte horizontal de aproximadamente 1,5 cm. </li><li> Faça dois cortes verticais das extremidades do corte horizontal anterior para os ombros, aproximadamente 1,5 cm cada. </li></ol></li><li> Corte através do diafragma e as junções costocondrais para expor o coração. </li><li> Com uma tesoura pequena mola, faça um pequeno, 2-5 mm cortar no átrio direito, a partir do ventral para dorsal lado do coração. </li><li> Usando uma seringa de 10 ml com uma agulha de 27G x 1/2 de polegada, injectar o ventrículo esquerdo e rapidamente perfundir o animal com elevado corte solução de sacarose. </li><li> Quando o sangue corre claro, usar a tesoura maiores para remover a cabeça. Nota: Não temos sistematicamente avaliada a utilidade da perfusão. No entanto, em nossa experiência, a perfusão transcardíaca em ratinhos jovens este pode ser feito com quase 100% de sucesso, e tem a vantagem de eliminar bl vermelhoood células, o que pode interferir com fluorescência e imagem. </li><li> Corte a pele para baixo da linha média para expor o crânio. </li><li> Usando íris dobrados tesoura, corte o crânio entre os olhos, em seguida, começando a partir do corte entre os olhos, cuidadosamente cortadas de anterior para posterior ao longo da sutura mediana tomando cuidado para não danificar o cérebro por baixo. Nota: A dura geralmente sai com o crânio. Se necessário, retire a dura antes de retirar cuidadosamente o cérebro. </li><li> Usando uma pinça joalheiro, forçar a abertura do crânio e remova cuidadosamente o cérebro, em seguida, colocar o cérebro em solução de corte. Tome cuidado para não danificar o córtex. </li></ol></li></ol> 2. Preparação do cérebro por Cortando <ol><li> Preparando cérebro para montagem em vibratome palco. <ol><li> Usando uma lâmina marcada com duas linhas a 90 o e uma linha diagonal em 17 o da parte superior esquerda para a direita inferior, interseção onde as duas linhas se encontram, coloque o lado do cérebro dorsal para cima, utilizandouma lâmina de barbear, de 2-4 mm de remover o cérebro extremidade rostral criando uma superfície plana. </li><li> Coloque cérebro lado do caudal sobre a superfície plana recentemente criado, e alinhar a superfície dorsal do cérebro com a horizontal e da linha média do cérebro com a linha vertical. </li><li> Alinhe a lâmina de barbear com a linha 17 o, incline a lâmina em um ângulo de 30 ° e retire cerca de 3 mm do córtex direito em um corte diagonal duplo (17 o do plano horizontal e 60 o do coronal). </li></ol></li><li> Montagem cérebro em vibratome palco. <ol><li> Coloque um pequeno pedaço de papel de filtro de 1 cm x 2 cm sobre o lado ventral do cérebro, de forma que a dimensão do comprimento é perpendicular à linha mediana. </li><li> Cuidadosamente aplicar uma pequena quantidade de adesivo de cianoacrilato para a área em frente do batente traseiro (e para a esquerda da colisão). </li><li> Coloque o cérebro diagonalmente duplo corte para a cola de modo a que a parte caudal do cérebro e do encéfalo posterior são prOP sobre a colisão eo lado direito do cérebro é contra o anti-retorno. </li><li> Delicadamente pressionar para baixo sobre o cérebro, assegurando que toda a superfície está em contacto com a câmara de corte. </li></ol></li></ol> 3. A obtenção da Colliculo-tálamo-cortical Slice <ol><li> Assumir rapidamente o estágio de corte e coloque no vibratome, encher o palco com uma solução de corte. </li><li> Alinhar a lâmina com a parte superior (lado ventral) no cérebro. </li><li> Remover 1-1,5 mm a partir do topo do cérebro, remova 300-500 uM fatias e avaliar profundidade após a remoção. Nota: Quando o IC, o MGB, eo núcleo geniculado lateral (LGN) são visíveis, eo giro dentado forma uma forma &#39;C&#39; levar de um a dois 600 um fatias. Ver a Figura 3A. </li><li> Coloque as fatias em câmara quente (32 ° C), segurando. </li></ol> 4. Criação de Imagens do Slice <ol><li> Preparação para a imagem latente flavoprotein autofluorescência. <ol> &lt;li&gt; Preparar aCSF pela perfusão da fatia numa câmara de registo electrofisiológico padrão, bolha aCSF com 95% de O2 / 5% de CO 2. </li><li> Puxe eletrodo de vidro para a estimulação. Observe que vários eletrodos estimulantes diferentes e configurações (vidro, tungsténio, fibra de carbono, monopolar, bipolar) todo o trabalho muito bem em conjunto com imagiologia flavoprotein autofluorescência. </li><li> Ligue computador, câmera, micromanipulador, fonte de luz, estimulação software, software de captura de imagem. </li><li> Perfundir a câmara de gravação com oxigenado aCSF, coloque ponte personalizado (projeto disponível em Materiais Complementares) para elevar a fatia na câmara. Nota: taxa de perfusão pode variar de acordo com qualquer indivíduo configurar; 5-15 mL / min é usada aqui. </li><li> Coloque fatia na câmara, diminuir o nível de líquido na câmara para evitar que a fatia de levantar fora da ponte ao colocar harpa especialmente construído sobre fatia, tendo o cuidado de evitar a colocação de cordas da harpa sobre as vias de cooperação interEst (Figura 1A). Aumentar o nível de líquido para cerca de 1-2 mm acima da fatia para manter o fluxo aCSF acima e abaixo da fatia. Nota: Se o reposicionamento é necessário, use o fim Pasteur pipeta quebrado ou permitir que o nível aCSF a subir e utilize uma pinça com extremo cuidado. </li><li> Inserir eletrodos de cloreto de prata em eletrodo de vidro cheio de aCSF, insira o eletrodo de vidro em micromanipulador e conectar-se ao estímulo isolador, e coloque cuidadosamente eletrodo de vidro no IC / substância branca levando a tálamo (ver Figura 1A). </li></ol></li><li> Flavoproteína aquisição de imagem autofluorescência. <ol><li> Coletar imagens em 4 Hz (usando uma macro 2X objetivo corrigido ao infinito (NA 0,13)) e uma câmera para 105 seg enquanto estimular eletricamente (cada estímulo consiste de 1 seg de 40 Hz 2 ms pulsos tecido em 0,05 Hz cinco vezes), enquanto iluminando o tecido com luz azul 470-490 nm e 515 nm capturar acima. Certifique-se de que a imagem não é nem aVeja o escuro, nem apagado Figura 3 coluna esquerda para referência. Nota: Coleção tempo, frequência de recolha, e freqüência de estimulação pode ser alterado para se adequar ao experimento, o programa personalizado incluído no materiais complementares podem ser modificados como tal. </li><li> Exportar imagens para Matlab, e utilizando o programa de escrita feito sob encomenda disponível em materiais complementares, para análise espectral de potência das imagens em 0,05 Hz. A imagem resultante mostrará vias conectados. Nota: O programa personalizado usa uma transformação Fourier rápida dos valores de pixel da série histórica para produzir a imagem. </li></ol></li><li> Preparação para a imagiologia de cálcio. <ol><li> Prepare pequena câmara de incubação utilizando um prato de cultura de 3 cm e membrana cultura levantada para permitir aCSF para alcançar a parte superior e inferior da fatia, e lugar numa almofada de aquecimento para manter a temperatura a cerca de 32 o C. </li><li> Preencha pequena câmara de incubação com aCSF morna e lentamente bolha com 95% O2/5% de CO 2. </li><li> Misturar 2 ul de Pluronic F-127 de ácido e 50 ug de Fura-02:00 dissolvido em 48 ul de DMSO. </li><li> Lugar em fatia pequena câmara de incubação na membrana levantou e cuidadosamente usando uma micropipeta adicione a mistura de coloração diretamente acima do MGB (ou outra estrutura de interesse). </li><li> Cubra fatias para prevenir o branqueamento antes da imagiologia, e permitem fatias a incubar durante 45 minutos - 1 hora. </li><li> Retire as fatias a câmara de retenção aquecida para 10-15 minutos para lavar o excesso de material. </li><li> Siga os passos 4.1.1 a 4.1.6 para preparação de estimular e imagem da fatia colliculo-tálamo-cortical. </li></ol></li><li> Aquisição de imagem de cálcio. <ol><li> Coletar imagens em 10 Hz (utilizando uma objectiva de imersão 20X de água) por 25 segundos enquanto estimular eletricamente (cada estímulo consiste de um pulso de 2 ms) tecido a 0,2 Hz cinco vezes enquanto iluminando o tecido com 365 nm de luz e capturando fluorescência acima de 510 nm. </li&gt; <li> Exportar imagens para Matlab e usar o programa escrito costume disponíveis em materiais complementares, para análise espectral de potência das imagens em 0.2 Hz. A imagem resultante mostrará células activas. </li></ol></li></ol>

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The authors have nothing to disclose.

This protocol describes improvements upon a previously described colliculo-thalamocortical brain slice in p12-20 mouse to study information flow in the auditory system1. This method has a number of advantages over other, similar, brain slice preparations by retaining connections between more brain areas in a single slice, which gives investigators new tools to understand the interaction and interplay between auditory nuclei in the forebrain. There have been a few key modifications in this protocol, compared to...

No sistema auditivo, embora não haja processamento substancial de informação entre a periferia sensorial e colículo inferior, existe uma considerável processamento adicional antes que ela atinja o córtex auditivo. Sabemos muito pouco sobre como esse processamento é feito e, portanto, pouco sobre como essa transformação permite que o cérebro para interpretar informação sensorial recebida. Com a excepção do olfacto, cada um dos sentidos tem uma estrutura muito semelhante com sinais periféricos inicialmente ser retransmitido com alta fidelidade, que diminui à medida que o sinal sobe para o córtex. O córtex, em seguida, envia projecções para as estruturas inferiores para modular ainda mais a informação recebida. Este sistema complexo tem sido estudada numa variedade de maneiras in vivo, bem como em um número de preparações in vitro. No primeiro caso, todas as ligações estão intactas, permitindo que o pesquisador sondar qualquer conjunto de ligações, enquanto se controla a entrada sensorial e medindosaída em qualquer área. Com essa abordagem, há pouco ou nenhum controlo da grande variedade de outros factores de produção, incluindo outras entradas sensoriais, excitação e atenção, dando origem a uma produção intensamente complexo. In vitro, fatias de cérebro foram cortados para capturar um único set de projecções, ou duas áreas do cérebro ligadas, que permitem que pesquisadores para estimular e avaliar vários aferentes ou áreas do cérebro. Estes são muitas vezes fatias quer talamocorticais ou tectothalamic onde quer a entrada para o tálamo ou no tálamo e sua saída para o córtex são preservados 2-5. Estas preparações permitem uma ampla variedade de manipulações farmacológicas, elétricas e optogenética. No entanto, com apenas duas regiões do cérebro, que avaliam principalmente à transferência de informações e falta a capacidade de avaliar a transformação de informação à medida que passa através do tálamo. Além disso, a projecção reticulo-tálamo, o que pode jogar um papel na modulação da atenção é 6-9 PRESENT nesta fatia. Aqui demonstramos melhorias sobre nossa preparação anterior 1, que permite o controle investigador de várias entradas para o tálamo para dar uma perspectiva única de como os portões tálamo e filtros de informação. Nós casal Esta preparação fatia romance com imagens flavoprotein autofluorescência para avaliar a conectividade fatia e análise de ativação de grande escala, a imagem latente de cálcio no tálamo para análise da população neuronal, e gravação de uma única célula para medir o impacto das várias entradas em um nível única célula. Para auxiliar na manutenção destas ligações generalizadas nós também têm desenvolvido uma série de modificações do âncora fatia normal (aka &quot;harpa&quot;) para a realização da fatia do cérebro no lugar e uma ponte para elevar a fatia para maior perfusão. A harpa é projetado em forma de ferradura modificado para cercar a fatia e permitir a pontos de fixação personalizáveis ​​para as cordas da harpa. Três cordas sãoligado de tal modo que i) um encontra-se horizontalmente ao longo do bordo medial da fatia, ii) estende-se a partir da extremidade caudal do IC para a extremidade caudal do CA e iii) estende-se na diagonal a partir do bordo medial da fatia para uma área rostral à AC (ver Figura 1A). Pequenos recortes no quadro para colagem (com cola de cianoacrilato) de harpas cordas para permitir uma diminuição da quantidade de pressão sobre a fatia para ajudar a manter a integridade da fatia (ver Figura 1B). Ao usar a impressão tridimensional, somos capazes de harpas de design personalizado com as nossas especificações únicas, bem como pontes que permitem o fluxo ideal de artificial líquido cefalorraquidiano (aCSF) acima e abaixo do tecido. Isso também mantém grandes áreas para a luz para penetrar no tecido para patch-clamp eletrofisiologia.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>High sucrose cutting solution</td>
			<td></td>
			<td></td>
			<td>in mM: 206 sucrose, 10.0 MgCl2, 11.0 glucose, 1.25 NaH2PO4, 26 NaHCO3, 0.5 CaCl2, 2.5 KCl, pH 7.4</td>
		</tr>
		<tr>
			<td>Low calcium aCSF</td>
			<td></td>
			<td></td>
			<td>in mM: 126 NaCl, 3.0 MgCl2, 10.0 glucose, 1.25 NaH2PO4, 26 NaHCO3, 1.0 CaCl2, 2.5 KCl, pH 7.4</td>
		</tr>
		<tr>
			<td>aCSF</td>
			<td></td>
			<td></td>
			<td>in mM: 126 NaCl, 2.0 MgCl2, 10.0 glucose, 1.25 NaH2PO4, 26 NaHCO3, 2.0 CaCl2, 2.5 KCl, pH 7.4</td>
		</tr>
		<tr>
			<td>Stimulus Isolator</td>
			<td>World Precision Instruments</td>
			<td>A360</td>
			<td></td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Life Technologies</td>
			<td>D12345</td>
			<td>Lot: 1572C502</td>
		</tr>
		<tr>
			<td>Fura-2AM</td>
			<td>Life Technologies</td>
			<td>F1201</td>
			<td>Lot: 144912</td>
		</tr>
		<tr>
			<td>Pluronic F-127</td>
			<td>Life Technologies</td>
			<td>P3000MP</td>
			<td>Lot: 1499369</td>
		</tr>
		<tr>
			<td>Large culture dish</td>
			<td>Fisherbrand</td>
			<td>08-757-13</td>
			<td>100x15mm culture dish</td>
		</tr>
		<tr>
			<td>Small culture dish</td>
			<td>Falcon</td>
			<td align="right">353001</td>
			<td>35x10mm culture dish</td>
		</tr>
		<tr>
			<td>Raised culture membrane</td>
			<td>Millicell</td>
			<td>PICMORG50</td>
			<td>Used to maintain oxygenated fluid perfusion on both sides of slice.</td>
		</tr>
		<tr>
			<td>Flavoprotein imaging fluorescence cube</td>
			<td>Olympus</td>
			<td>UMNIB</td>
			<td>470&#8211;490 nm excitation, 505 nm dichroic, 515 nm emission long pass.&#160; We have found that virtually any green fluorescence protein filter cube will work here.</td>
		</tr>
		<tr>
			<td>Calcium imaging fluorescence cube</td>
			<td>Omega Optical</td>
			<td>BX-18</td>
			<td>XF1005 365nm exitation, XF2001 400nm dichroic, XF3080 510nm emission</td>
		</tr>
		<tr>
			<td>Agar for blocking brain</td>
			<td></td>
			<td></td>
			<td>3% by weight in water</td>
		</tr>
		<tr>
			<td>Viper si Stereo Lithography Apparatus</td>
			<td>3D Systems</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

modification of a colliculo-thalamocortical mouse brain slice, incorporating 3-d printing of chamber components and multi-scale optical imaging

The ability of the brain to process sensory information relies on both ascending and descending sets of projections. Until recently, the only way to study these two systems and how they interact has been with the use of in vivo preparations. Major advances have been made with acute brain slices containing the thalamocortical and cortico-thalamic pathways in the somatosensory, visual, and auditory systems. With key refinements to our recent modification of the auditory thalamocortical slice1, we are able to more reliably capture the projections between most of the major auditory midbrain and forebrain structures: the inferior colliculus (IC), medial geniculate body (MGB), thalamic reticular nucleus (TRN), and the auditory cortex (AC). With portions of all these connections retained, we are able to answer detailed questions that complement the questions that can be answered with in vivo preparations. The use of flavoprotein autofluorescence imaging enables us to rapidly assess connectivity in any given slice and guide the ensuing experiment. Using this slice in conjunction with recording and imaging techniques, we are now better equipped to understand how information processing occurs at each point in the auditory forebrain as information ascends to the cortex, and the impact of descending cortical modulation. 3-D printing to build slice chamber components permits double-sided perfusion and broad access to networks within the slice and maintains the widespread connections key to fully utilizing this preparation.

Um exemplo de fatia de cérebro de ratinho colliculo-talamocortical obtido em P15 rato é mostrada na Figura 2. A fatia ideal irá conter os quatro principais estruturas auditivas do mesencéfalo e do prosencéfalo IC, MGB, TRN, e AC, que são activados quando o IC é estimulada (Figura 2A). Usando a análise de Fourier, o poder espectral é medido na frequência de estimulação elétrica, com regiões do cérebro ligadas mostrando atividade que é periódica e arrasta...

Watch this Scientific Journal Video about Modification of a Colliculo-thalamocortical Mouse Brain Slice, Incorporating 3-D printing of Chamber Components and Multi-scale Optical Imaging at JoVE.com

Modification of a Colliculo-thalamocortical Mouse Brain Slice, Incorporating 3-D printing of Chamber Components and Multi-scale Optical Imaging

O uso de vários ângulos para cortar o cérebro do rato filhote, podemos melhorar em cima de uma fatia cerebral aguda anteriormente descrito que captura as conexões entre a maioria dos principais mesencéfalo e prosencéfalo estruturas auditivas.

A modificação de um Colliculo-tálamo-cortical do cérebro do rato Fatia, Incorporando a impressão 3-D da Câmara Components and Imaging Optical Multi-escala

The ability of the brain to process sensory information relies on both ascending and descending sets of projections. Until recently, the only way to study ...

modification-colliculo-thalamocortical-mouse-brain-slice

Research

JoVE Journal

Neuroscience

8.2K visualizações.  University of Illinois Urbana-Champaign.  O uso de vários ângulos para cortar o cérebro do rato filhote, podemos melhorar em cima de uma fatia cerebral aguda anteriormente descrito que captura as conexões entre a maioria dos principais mesencéfalo e prosencéfalo estruturas auditivas. 

Vídeo: Modification of a Colliculo-thalamocortical Mouse Brain Slice, Incorporating 3-D printing of Chamber Components and Multi-scale Optical Imaging

Scalable Fluidic Injector Arrays for Viral Targeting of Intact 3-D Brain Circuits

Our understanding of neural circuits--how they mediate the computations that subserve sensation, thought, emotion, and action, and how they are corrupted in neurological and psychiatric disorders--would be greatly facilitated by a technology for rapidly targeting genes to complex 3-dimensional neural circuits, enabling fast creation of "circuit-level transgenics." We have recently developed methods in which viruses encoding for light-sensitive proteins can sensitize specific cell types to millisecond-timescale activation and silencing in the intact brain. We here present the design and implementation of an injector array capable of delivering viruses (or other fluids) to dozens of defined points within the 3-dimensional structure of the brain (Figure. 1A, 1B). The injector array comprises one or more displacement pumps that each drive a set of syringes, each of which feeds into a polyimide/fused-silica capillary via a high-pressure-tolerant connector. The capillaries are sized, and then inserted into, desired locations specified by custom-milling a stereotactic positioning board, thus allowing viruses or other reagents to be delivered to the desired set of brain regions. To use the device, the surgeon first fills the fluidic subsystem entirely with oil, backfills the capillaries with the virus, inserts the device into the brain, and infuses reagents slowly (&lt;0.1 microliters/min). The parallel nature of the injector array facilitates rapid, accurate, and robust labeling of entire neural circuits with viral payloads such as optical sensitizers to enable light-activation and silencing of defined brain circuits. Along with other technologies, such as optical fiber arrays for light delivery to desired sets of brain regions, we hope to create a toolbox that enables the systematic probing of causal neural functions in the intact brain. This technology may not only open up such systematic approaches to circuit-focused neuroscience in mammals, and facilitate labeling of brain regions in large animals such as non-human primates, but may also open up a clinical translational path for cell-specific optical control prosthetics, whose precision may enable improved treatment of intractable brain disorders. Finally, such devices as described here may facilitate precisely-timed fluidic delivery of other payloads, such as stem cells and pharmacological agents, to 3-dimensional structures, in an easily user-customizable fashion.

Controlling and analyzing neural circuits in vivo would be facilitated by a technology for delivery of viruses and other reagents to desired 3-dimensional sets of brain regions. We demonstrate customized fluidic injector array fabrication, and delivery of virally-encoded optical sensitizers, enabling optical manipulation of complex brain circuits.

Escalável Fluidic Arrays Injector para Viral Segmentação de Intact Circuitos 3-D do cérebro

Our understanding of neural circuits--how they mediate the computations that subserve sensation, thought, emotion, and action, and how they are corrupted ...

Neurociência

Multiple-mouse Neuroanatomical Magnetic Resonance Imaging

The field of mouse phenotyping with magnetic resonance imaging (MRI) is rapidly growing, motivated by the need for improved tools for characterizing and evaluating mouse models of human disease. MRI is an excellent modality for investigating genetically altered animals. It is capable of whole brain coverage, can be used in vivo, and provides multiple contrast mechanisms for investigating different aspects of neuranatomy and physiology. The advent of high-field scanners along with the ability to scan multiple mice simultaneously allows for rapid phenotyping of novel mutations.
Effective mouse MRI studies require attention to many aspects of experiment design. In this article, we will describe general methods to acquire quality images for mouse phenotyping using a system that images mice concurrently in shielded transmit/receive radio frequency (RF) coils in a common magnet (Bock et al., 2003). We focus particularly on anatomical phenotyping, an important and accessible application that has shown a high potential for impact in many mouse models at our imaging centre. Before we can provide the detailed steps to acquire such images, there are important practical considerations for both in vivo brain imaging (Dazai et al., 2004) and ex vivo brain imaging (Spring et al., 2007) that should be noted. These are discussed below.

Magnetic resonance imaging (MRI) has become an increasingly popular tool for examining the phenotype of genetically altered mice. This article illustrates the methods necessary to achieve high-throughput phenotyping of genetically altered mice using multiple-mouse MRI.

Múltiplas mouse-Imagem por Ressonância Magnética neuroanatômicos

The field of mouse phenotyping with magnetic resonance imaging (MRI) is rapidly growing, motivated by the need for improved tools for characterizing and ...

Imaging Pheromone Sensing in a Mouse Vomeronasal Acute Tissue Slice Preparation

Peter Karlson and Martin L&uuml;scher used the term pheromone for the first time in 19591 to describe chemicals used for intra-species communication. Pheromones are volatile or non-volatile short-lived molecules2 secreted and/or contained in biological fluids3,4, such as urine, a liquid known to be a main source of pheromones3. Pheromonal communication is implicated in a variety of key animal modalities such as kin interactions5,6, hierarchical organisations3 and sexual interactions7,8 and are consequently directly correlated with the survival of a given species9,10,11. In mice, the ability to detect pheromones is principally mediated by the vomeronasal organ (VNO)10,12, a paired structure located at the base of the nasal cavity, and enclosed in a cartilaginous capsule. Each VNO has a tubular shape with a lumen13,14 allowing the contact with the external chemical world. The sensory neuroepithelium is principally composed of vomeronasal bipolar sensory neurons (VSNs)15. Each VSN extends a single dendrite to the lumen ending in a large dendritic knob bearing up to 100 microvilli implicated in chemical detection16. Numerous subpopulations of VSNs are present. They are differentiated by the chemoreceptor they express and thus possibly by the ligand(s) they recognize17,18. Two main vomeronasal receptor families, V1Rs and V2Rs19,20,21,22, are composed respectively by 24023 and 12024 members and are expressed in separate layers of the neuroepithelium. Olfactory receptors (ORs)25 and formyl peptide receptors (FPRs)26,27 are also expressed in VSNs.
Whether or not these neuronal subpopulations use the same downstream signalling pathway for sensing pheromones is unknown. Despite a major role played by a calcium-permeable channel (TRPC2) present in the microvilli of mature neurons28 TRPC2 independent transduction channels have been suggested6,29. Due to the high number of neuronal subpopulations and the peculiar morphology of the organ, pharmacological and physiological investigations of the signalling elements present in the VNO are complex.
Here, we present an acute tissue slice preparation of the mouse VNO for performing calcium imaging investigations. This physiological approach allows observations, in the natural environment of a living tissue, of general or individual subpopulations of VSNs previously loaded with Fura-2AM, a calcium dye. This method is also convenient for studying any GFP-tagged pheromone receptor and is adaptable for the use of other fluorescent calcium probes. As an example, we use here a VG mouse line30, in which the translation of the pheromone V1rb2 receptor is linked to the expression of GFP by a polycistronic strategy.

In mice, the ability to detect pheromones is principally mediated by the vomeronasal organ (VNO). Here, an acute tissue slice preparation of VNO for performing calcium imaging is described. This physiological approach allows observations of subpopulations and/or individual neurons in a living tissue and is convenient for receptor-ligand identification.

Imagem Pheromone Sensing em um Preparação Slice rato Vomeronasal aguda do tecido

Peter Karlson and Martin L&uuml;scher used the term pheromone for the first time in 19591 to describe chemicals used for intra-species communication. ...

A Procedure for Implanting a Spinal Chamber for Longitudinal In Vivo Imaging of the Mouse Spinal Cord

Studies in the mammalian neocortex have enabled unprecedented resolution of cortical structure, activity, and response to neurodegenerative insults by repeated, time-lapse in vivo imaging in live rodents. These studies were made possible by straightforward surgical procedures, which enabled optical access for a prolonged period of time without repeat surgical procedures. In contrast, analogous studies of the spinal cord have been previously limited to only a few imaging sessions, each of which required an invasive surgery. As previously described, we have developed a spinal chamber that enables continuous optical access for upwards of 8 weeks, preserves mechanical stability of the spinal column, is easily stabilized externally during imaging, and requires only a single surgery. Here, the design of the spinal chamber with its associated surgical implements is reviewed and the surgical procedure is demonstrated in detail. Briefly, this video will demonstrate the preparation of the surgical area and mouse for surgery, exposure of the spinal vertebra and appropriate tissue debridement, the delivery of the implant and vertebral clamping, the completion of the chamber, the removal of the delivery system, sealing of the skin, and finally, post-operative care. The procedure for chronic in vivo imaging using nonlinear microscopy will also be demonstrated. Finally, outcomes, limitations, typical variability, and a guide for troubleshooting are discussed.

A Procedure for Implanting a Spinal Chamber for Longitudinal In Vivo Imaging of the Mouse Spinal Cord

In this video, we describe a procedure for implanting a chronic optical imaging chamber over the dorsal spinal cord of a live mouse. The chamber, surgical procedure, and chronic imaging are reviewed and demonstrated.

Um Processo de Implantação de uma Câmara Spinal para Longitudinal<em&gt; In Vivo</em&gt; Criação de Imagens do Cordão do rato Spinal

Studies in the mammalian neocortex have enabled unprecedented resolution of cortical structure, activity, and response to neurodegenerative insults by ...

Whole-mount Imaging of Mouse Embryo Sensory Axon Projections

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

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

Todo-mount imagem de embrião de rato Projeções Sensorial Axon

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

3-D Imaging and Analysis of Neurons Infected In Vivo with Toxoplasma gondii

Toxoplasma gondii is an obligate, intracellular parasite with a broad host range, including humans and rodents. In both humans and rodents, Toxoplasma establishes a lifelong persistent infection in the brain. While this brain infection is asymptomatic in most immunocompetent people, in the developing fetus or immunocompromised individuals such as acquired immune deficiency syndrome (AIDS) patients, this predilection for and persistence in the brain can lead to devastating neurologic disease. Thus, it is clear that the brain-Toxoplasma interaction is critical to the symptomatic disease produced by Toxoplasma, yet we have little understanding of the cellular or molecular interaction between cells of the central nervous system (CNS) and the parasite. In the mouse model of CNS toxoplasmosis it has been known for over 30 years that neurons are the cells in which the parasite persists, but little information is available about which part of the neuron is generally infected (soma, dendrite, axon) and if this cellular relationship changes between strains. In part, this lack is secondary to the difficulty of imaging and visualizing whole infected neurons from an animal. Such images would typically require serial sectioning and stitching of tissue imaged by electron microscopy or confocal microscopy after immunostaining. By combining several techniques, the method described here enables the use of thick sections (160 &#181;m) to identify and image whole cells that contain cysts, allowing three-dimensional visualization and analysis of individual, chronically infected neurons without the need for immunostaining, electron microscopy, or serial sectioning and stitching. Using this technique, we can begin to understand the cellular relationship between the parasite and the infected neuron.

3-D Imaging and Analysis of Neurons Infected In Vivo with Toxoplasma gondii

Using this protocol, we were able to image 160 &#181;m thick brain sections from mice infected with the parasite Toxoplasma gondii, which enables visualization and analysis of the spatial relationship between the encysting parasite and the infected neuron.

Imagem 3-D e Análise de Neurônios Infected<em&gt; In Vivo</em&gt; Com<em&gt; Toxoplasma gondii</em

Toxoplasma gondii is an obligate, intracellular parasite with a broad host range, including humans and rodents. In both humans and rodents, Toxoplasma ...

A Large Lateral Craniotomy Procedure for Mesoscale Wide-field Optical Imaging of Brain Activity

The craniotomy is a commonly performed procedure to expose the brain for in vivo experiments. In mouse research, most labs utilize a small craniotomy, typically 3 mm x 3 mm. This protocol introduces a method for creating a substantially larger 7 mm x 6 mm cranial window exposing most of a cerebral hemisphere over the mouse temporal and parietal cortices (e.g., bregma 2.5 - 4.5 mm, lateral 0 - 6 mm). To perform this surgery, the head must be tilted approximately 30&#176; and much of the temporal muscle must be retracted. Due to the large amount of bone removal, this procedure is intended only for acute experiments with the animal anesthetized throughout the surgery and experiment.
The main advantage of this innovative large lateral cranial window is to provide simultaneous access to both medial and lateral areas of the cortex. This large unilateral cranial window can be used to study the neural dynamics between cells, as well as between different cortical areas by combining multi-electrode electrophysiological recordings, imaging of neuronal activity (e.g., intrinsic or extrinsic imaging), and optogenetic stimulation. Additionally, this large craniotomy also exposes a large area of cortical blood vessels, allowing for direct manipulation of the lateral cortical vasculature.

This protocol presents a method for creating a large unilateral craniotomy over the temporal and parietal regions of the mouse cerebral cortex. This is especially useful for real time imaging over an expansive area of a cortical hemisphere.

Um Procedimento craneotomia Lateral Grande para Wide-campo Mesoscale imagens ópticas de atividade cerebral

The craniotomy is a commonly performed procedure to expose the brain for in vivo experiments. In mouse research, most labs utilize a small craniotomy, ...

Live Imaging of the Ependymal Cilia in the Lateral Ventricles of the Mouse Brain

Multiciliated ependymal cells line the ventricles in the adult brain. Abnormal function or structure of ependymal cilia is associated with various neurological deficits. The current ex vivo live imaging of motile ependymal cilia technique allows for a detailed study of ciliary dynamics following several steps. These steps include: mice euthanasia with carbon dioxide according to protocols of The University of Toledo&#8217;s Institutional Animal Care and Use Committee (IACUC); craniectomy followed by brain removal and sagittal brain dissection with a vibratome or sharp blade to obtain very thin sections through the brain lateral ventricles, where the ependymal cilia can be visualized. Incubation of the brain&#8217;s slices in a customized glass-bottom plate containing Dulbecco&#8217;s Modified Eagle&#8217;s Medium (DMEM)/High-Glucose at 37 &#176;C in the presence of 95%/5% O2/CO2 mixture is essential to keep the tissue alive during the experiment. A video of the cilia beating is then recorded using a high-resolution differential interference contrast microscope. The video is then analyzed frame by frame to calculate the ciliary beating frequency. This allows distinct classification of the ependymal cells into three categories or types based on their ciliary beating frequency and angle. Furthermore, this technique allows the use of high-speed fluorescence imaging analysis to characterize the unique intracellular calcium oscillation properties of ependymal cells as well as the effect of pharmacological agents on the calcium oscillations and the ciliary beating frequency. In addition, this technique is suitable for immunofluorescence imaging for ciliary structure and ciliary protein localization studies. This is particularly important in disease diagnosis and phenotype studies. The main limitation of the technique is attributed to the decrease in live motile cilia movement as the brain tissue starts to die.

Using high-resolution differential interference contrast (DIC) microscopy, an ex vivo observation of the beating of motile ependymal cilia located within the mouse brain ventricles is demonstrated by live-imaging. The technique allows a recording of the unique ciliary beating frequency and beating angle as well as their intracellular calcium oscillation pacing properties.

Imagens ao vivo da ependimária Cilia nas laterais ventrículos do cérebro do rato

Multiciliated ependymal cells line the ventricles in the adult brain. Abnormal function or structure of ependymal cilia is associated with various ...

Time-lapse Confocal Imaging of Migrating Neurons in Organotypic Slice Culture of Embryonic Mouse Brain Using In Utero Electroporation

In utero electroporation is a rapid and powerful approach to study the process of radial migration in the cerebral cortex of developing mouse embryos. It has helped to describe the different steps of radial migration and characterize the molecular mechanisms controlling this process. To directly and dynamically analyze migrating neurons they have to be traced over time. This protocol describes a workflow that combines in utero electroporation with organotypic slice culture and time-lapse confocal imaging, which allows for a direct examination and dynamic analysis of radially migrating cortical neurons. Furthermore, detailed characterization of migrating neurons, such as migration speed, speed profiles, as well as radial orientation changes, is possible. The method can easily be adapted to perform functional analyses of genes of interest in radially migrating cortical neurons by loss and gain of function as well as rescue experiments. Time-lapse imaging of migrating neurons is a state-of-the-art technique that once established is a potent tool to study the development of the cerebral cortex in mouse models of neuronal migration disorders.

Time-lapse Confocal Imaging of Migrating Neurons in Organotypic Slice Culture of Embryonic Mouse Brain Using In Utero Electroporation

This protocol provides instructions for direct observation of radially migrating cortical neurons. In utero electroporation, organotypic slice culture, and time-lapse confocal imaging are combined to directly and dynamically study the effects of overexpression or downregulation of genes of interest in migrating neurons and to analyze their differentiation during development.

Imaginação confocal de lapso de tempo de neurônios migratórios na cultura de fatias organotípicas do cérebro de mouse embrionário Usando<em&gt; Em Utero</em&gt; Electroporação

In utero electroporation is a rapid and powerful approach to study the process of radial migration in the cerebral cortex of developing mouse embryos. It ...

Recording Synaptic Plasticity in Acute Hippocampal Slices Maintained in a Small-volume Recycling-, Perfusion-, and Submersion-type Chamber System

Even though experiments on brain slices have been in use since 1951, problems remain that reduce the probability of achieving a stable and successful analysis of synaptic transmission modulation when performing field potential or intracellular recordings. This manuscript describes methodological aspects that might be helpful in improving experimental conditions for the maintenance of acute brain slices and for recording field excitatory postsynaptic potentials in a commercially available submersion chamber with an outflow-carbogenation unit. The outflow-carbogenation helps to stabilize the oxygen level in experiments that rely on the recycling of a small buffer reservoir to enhance the cost-efficiency of drug experiments. In addition, the manuscript presents representative experiments that examine the effects of different carbogenation modes and stimulation paradigms on the activity-dependent synaptic plasticity of synaptic transmission.

This protocol describes the stabilization of the oxygen level in a small volume of recycled buffer and methodological aspects of recording activity-dependent synaptic plasticity in submerged acute hippocampal slices.

Gravação de plasticidade sináptica em fatias Hippocampal agudas, mantidas em um pequeno volume reciclagem - perfusão- e sistema de câmara de submersão-tipo

Even though experiments on brain slices have been in use since 1951, problems remain that reduce the probability of achieving a stable and successful ...