Reconhecemos as seguintes fontes de financiamento: NIH NINDS – K08NS101122 (JB), R01NS040337 (JK), R01NS044370 (JK), University of Virginia School of Medicine (JB).

Todos os estudos em animais foram aprovados pelo Comitê Institucional de Cuidados e Uso de Animais (IACUC) da Universidade da Virgínia.
1. Construção de eletrodo/cabo
<ol><li>Use um fio de aço inoxidável isolado unipolar (0,005" de diâmetro nu, 0,008" revestido) para fazer um eletrodo conectado com um conector de soquete feminino (conector de recipiente feminino 0,079).</li>
	<li>Use um cabo feito sob medida para conectar os animais ao amplificador.<ol>
<li>Conecte um conector masculino de 4 pinos (conector masculino de 0,079") à unidade de 4 canais ganha impedância correspondente ao amplificador operacional (op-amp). Conecte um resistor de 10K aos fios que se conectam à bateria de 9 V. Um fio de terra não conectado ao op-amp atua como o ponto médio da bateria.</li>
		<li>Conecte uma extremidade do cabo (AWG, 0,012" OD) ao op-amp e conecte a outra extremidade do cabo ao amplificador.</li>
	</ol>
</li>
</ol>2. Cirurgia de implantação de eletrodos
<ol><li>Anestesiar o filhote (pós-natal dia 9) com isoflurane de 4-5% em um capô de fluxo descendente. Antes do início do procedimento, injete os filhotes com bupivacaína (0,02-0,05 mL, 0,25% de infiltração local subcutânea).</li>
	<li>Uma vez que o animal esteja imóvel, transfira para um estágio estereotático com um cone de nariz. Use o lado inverso da barra de ouvido, pois ela é macia para manter a cabeça firme. Nesta idade, os filhotes não têm um ouvido totalmente desenvolvido para usar a extremidade pontiaguda da barra de ouvido.</li>
	<li>Abaixe o fluxo de isoflurane e mantenha-o em 2,5-3%. Fique de olho na respiração constante do filhote durante todo o procedimento cirúrgico. Aperte a cauda para verificar a resposta à dor e, em seguida, proceda à incisão.</li>
	<li>Esterilize a área de incisão no crânio com betadina e álcool (3 ciclos de iodo alternado e 70% de etanol). Drape a parte do corpo circundante de tal forma que a região de incisão é visível.</li>
	<li>Abra o couro cabeludo anterior-posterior ligeiramente acima dos olhos e retraia aproximadamente 0,5 cm de pele. Reposicione a cabeça do rato no estágio estereotaxico para que a pele puxe para fora expondo o crânio.</li>
	<li>Aplique peróxido de hidrogênio no crânio usando um cotonete e raspe o crânio limpo usando uma lâmina de bisturi. O crânio é muito macio; tenha cuidado ao raspar.</li>
	<li>Aplique uma gota (aproximadamente 50 μL) de adesivo e espalhe-a ao redor da área do crânio exposta usando seu aplicador. Exponha à luz UV por 40 s para definir o adesivo.</li>
	<li>Meça as coordenadas usando o bregma exposto como referência. Implante eletrodos bilateralmente na região ca1 do hipocampo [-3,5 mm Dorsal-Ventral (DV), ±2 mm Medial-Lateral (ML), -1,75 mm De profundidade (D)] e bilateralmente no córtex parietal [-1,22 mm DV, ±0,5 mm ML, -1 mm D] e um eletrodo de referência no cerebelo17. Use uma agulha de 32 G para criar um buraco na região marcada.</li>
	<li>Limpe o sangue da superfície do crânio. Eletrodos inferiores ligados ao conector do soquete feminino no cérebro com a ajuda do braço estereotaxic e fixação no lugar com acrílico dental. Implante o eletrodo no cérebro. O fone de ouvido do conector do soquete fica em cima do crânio colado por acrílico dentário.</li>
	<li>Injete cetoprofeno (5 mg/kg) subcutâneamente na região interescapular quando o eletrodo estiver fixo. Coloque os filhotes de volta com a mãe. NOTA: Introduza metade da ninhada com o fone de ouvido de uma vez para a mãe em vez de apresentá-los um de cada vez. Isso evitará que a mãe prejudique o fone de ouvido do filhote.</li>
</ol>3. Configuração e gravação do EEG (linha de base/pré-lesão)
<ol><li>Após 24 horas de recuperação após a implantação do eletrodo, coloque cada animal em uma câmara plexiglas personalizada (37 °C) para gravação de EEG. Esta câmara também servirá como uma câmara de hipóxia.</li>
	<li>Conecte filhotes na câmara a um sistema de monitoramento por vídeo-EEG através de um cabo flexível (cabo op-amp personalizado). NOTA: Com o fone de ouvido no lugar, os ratos são livremente móveis e não apresentam diferenças de comportamento. Uma vez fixados nos fios de eletrodo, os fios devem ser ajustados dentro da corda da câmara, a fim de fornecer a quantidade certa de folga para que o filhote possa se mover livremente por toda a câmara.</li>
	<li>Digitalize os dados do EEG a 1000 Hz com ganho de 1K usando um amplificador de grama. Revise o sinal EEG (filtro de passagem de banda entre 3-70 Hz) mais tarde usando software (por exemplo, LabChart Pro).</li>
	<li>Regisso EEG pré-lesão por 30 minutos antes de desconectar animais para procedimento de ligadura da artéria carótida.</li>
</ol>4. Ligamento da artéria carótida esquerda
<ol><li>Anestesiar o filhote (pós-natal dia 10) com isoflurane de 4-5% em um capô de fluxo descendente e colocá-los em configuração especialmente organizada em uma almofada de banho de água. Posicione o supino animal e proteja os membros dianteiros com fita adesiva.<ol>
<li>Reduza o fluxo de isoflurane para 2-3%. Belisque a cauda para obter resposta à dor e monitore a respiração durante todo o procedimento.</li>
	</ol>
</li>
	<li>Esterilizar a área de incisão (entre a mandíbula e a clavícula) no lado esquerdo do pescoço com betadina e álcool (3 ciclos de iodo alternado e 70% de etanol).</li>
	<li>Faça uma incisão de aproximadamente 1 cm de comprimento no lado esquerdo do pescoço usando microscisores. Usando um microscópio dissecando, retraia cuidadosamente o tecido subcutâneo e a pele para expor a artéria carótida. Tome cuidado para identificar o nervo vago (correndo lateralmente para a artéria) e delicadamente separá-lo e retraí-lo da artéria.</li>
	<li>Rosqueie uma sutura de seda estéril de 5 cm de comprimento sob a artéria usando microforceps. Amarre uma sutura dupla ao redor da artéria para ocluir o fluxo.</li>
	<li>Corte o excesso de sutura e feche a artéria exposta puxando para trás o tecido subcutâneo e a pele. Use o vínculo veterinário para selar a incisão.</li>
	<li>Coloque o animal de volta no monitoramento contínuo do EEG em uma câmara em temperatura ambiente, que é colocada em um colchão aquecido. Faça verificações de temperatura infravermelha do núcleo do filhote para evitar abrir a câmara. Deixe o animal se recuperar por 1h antes da hipóxia.</li>
</ol>5. EEG e hipóxia
<ol><li>Monitore continuamente o FiO2 (fração de oxigênio inspirado) dentro da câmara através de um monitor de oxigênio.</li>
	<li>Lave a câmara com 60 L/min de 100% N2 e 0,415 L/min para 100% O2. Uma vez que a saturação de oxigênio na câmara atinja 12%, diminua o fluxo de N2 para 10 L/min, mantendo o fluxo de O2 inalterado. Com pequenos ajustes, mantenha o FiO2 em 8% por 45 min.</li>
	<li>Após 45 min de exposição à hipóxia, retorne fio2 a 21%.</li>
	<li>Que os filhotes se recuperem na câmara e monitorem no EEG por 2h pós-hipóxia.</li>
	<li>Após o término do período de gravação, desconecte os ratos da gravação do EEG e retorne à mãe.</li>
</ol>6. Análise de EEG
<ol><li>Analise o arquivo EEG com vídeo no LabChart Pro. Um pesquisador cego marca o EEG para convulsões e padrões de fundo17. As convulsões são definidas como um evento eletrográfico que dura mais de 10 segundos com descargas de ondas acentuadas rítmica de alta frequência (≥3x de base) com clara evolução17.</li>
	<li>Tenha uma segunda revisão de pesquisador cego marcado eventos aleatoriamente para concordância.</li>
	<li>Revise o vídeo associado para cada evento eletrográfico marcado e analise de acordo com o escore de convulsão comportamental do roedor neonatal16. Resumidamente, essa pontuação varia de 0-6 (imobilidade ao comportamento tônico-clonic grave). Para caracterizar ainda mais a semiologia convulsiva, analise o comportamento de lateralidade (movimentos multifoca/bilaterais versus focal/unilateral versus misto).</li>
	<li>Crie um espectrograma de energia. Use um Fast Fourier Transform com uma janela de dados Cosine-Bell com um tamanho de 1024 pontos de dados. Crie um eixo x liso no espectrograma com a ajuda de uma sobreposição de janela de 87,5%. Expresse a potência como μV218.</li>
</ol>

<ol>
	<li>Vasudevan, C., Levene, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiology+and+aetiology+of+neonatal+seizures.">Epidemiology and aetiology of neonatal seizures.</a> Seminars in Fetal &amp; Neonatal Medicine. , (2013).</li><li>Volpe, J., 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=Neonatal+Seizures.">Neonatal Seizures.</a> Volpe's Neurology of the Newborn. , 275-321 (2018).</li><li>Shankaran, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Network+EKSNNR.+Childhood+outcomes+after+hypothermia+for+neonatal+encephalopathy.">Network EKSNNR. Childhood outcomes after hypothermia for neonatal encephalopathy.</a> New England Journal of Medicine. 366 (22), 2085-2092 (2012).</li><li>Pappas, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cognitive+outcomes+after+neonatal+encephalopathy.">Cognitive outcomes after neonatal encephalopathy.</a> Pediatrics. 135 (3), 624-634 (2015).</li><li>van Schie, P. E., 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=Long-term+motor+and+behavioral+outcome+after+perinatal+hypoxic-ischemic+encephalopathy.">Long-term motor and behavioral outcome after perinatal hypoxic-ischemic encephalopathy.</a> European Journal of Paediatric Neurology. 19 (3), 354-359 (2015).</li><li>Rensing, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Longitudinal+analysis+of+developmental+changes+in+electroencephalography+patterns+and+sleep-wake+states+of+the+neonatal+mouse.">Longitudinal analysis of developmental changes in electroencephalography patterns and sleep-wake states of the neonatal mouse.</a> PLoS One. 13 (11), 1-17 (2018).</li><li>Rice, J. E., Vannucci, R. C., Brierley, J. 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D., 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=Brain+development+in+rodents+and+humans:+Identifying+benchmarks+of+maturation+and+vulnerability+to+injury+across+species.">Brain development in rodents and humans: Identifying benchmarks of maturation and vulnerability to injury across species.</a> Progress in Neurobiology. , 1-16 (2013).</li><li>Comi, A. M., 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=Gabapentin+neuroprotection+and+seizure+suppression+in+immature+mouse+brain+ischemia.">Gabapentin neuroprotection and seizure suppression in immature mouse brain ischemia.</a> Pediatric Research. 64 (1), 81-85 (2008).</li><li>Comi, A. 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E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+Electroencephalographic+Monitoring+with+Radio-Telemetry+in+a+Rat+Model+of+Perinatal+Hypoxia-Ischemia+Reveals+Progressive+Post-Stroke+Epilepsy.">Continuous Electroencephalographic Monitoring with Radio-Telemetry in a Rat Model of Perinatal Hypoxia-Ischemia Reveals Progressive Post-Stroke Epilepsy.</a> Journal of Neuroscience. 30 (1), 404-415 (2010).</li><li>Burnsed, J., 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=Neuronal+Circuit+Activity+during+Neonatal+Hypoxic+-+Ischemic+Seizures+in+Mice.">Neuronal Circuit Activity during Neonatal Hypoxic - Ischemic Seizures in Mice.</a> Annals of Neurology. 86, 927-938 (2019).</li><li>Sampath, D., White, A. M., Raol, Y. 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Apresentamos um modelo para monitoramento contínuo de vídeo-EEG em camundongos neonatais durante convulsões hipoximic-isquêmicas. A análise de vídeo em conjunto com o EEG permite a caracterização da semiologia convulsiva. A análise do EEG permite a extração de espectrogramas de energia e análise de amplitude de fundo.
A colocação correta e cuidadosa de eletrodos é crucial neste protocolo, pois lesões durante a colocação de eletrodos ou colocação imprecisa podem afetar signi...

A encefalopatia isquêmica hipóxica (HIE) é uma condição que afeta 1,5 em 1000 recém-nascidos anualmente e é a causa mais comum de convulsões neonatais1,2. Os bebês que sobrevivem correm risco para várias deficiências neurológicas, como paralisia cerebral, deficiência intelectual e epilepsia3,4,5.
Os modelos animais desempenham um papel fundamental na compreensão e investigação da fisiopatologia da isquemia de hipóxia e convulsões neonatais6,7. Um modelo vannucci modificado é usado para induzir isquemia de hipóxia (OI) no pós-natal dia 10 (p10)7,8. Filhotes de rato dessa idade traduzem neurologicamente aproximadamente para o termo completo neonato humano9.
O monitoramento contínuo da eletroencefalografia por vídeo (EEG) utilizado em conjunto com este modelo de lesão permite maior compreensão e caracterização de convulsões isquêmicas hipoxicas neonatais. Estudos anteriores utilizaram vários métodos para análise de convulsões neonatais em roedores, incluindo gravações de vídeo, gravações limitadas de EEG e gravações de EEG de telemetria10,11,12,13,14,15,16. No manuscrito a seguir, discutimos em profundidade o processo de gravação contínua de EEG de vídeo em filhotes de camundongos durante a hipoxia-isquemia. Esta técnica de monitoramento contínuo de EEG em filhotes de camundongos neonatais pode ser aplicada a uma variedade de modelos de doenças e convulsões.

<table>
	<tbody>
		<tr>
			<td>SURGERY</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ball Point Applicator</td>
			<td>Metrex Research</td>
			<td>8300-F</td>
			<td>i-bond applicator</td>
		</tr>
		<tr>
			<td>Cranioplast (Powder/Resin)</td>
			<td>Coltene</td>
			<td>H00383</td>
			<td>Perm Reline/Power</td>
		</tr>
		<tr>
			<td>I-Bond</td>
			<td>Kulzer GmbH, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>LOOK Silk Suture</td>
			<td>Surgical Specialities Corporation</td>
			<td>SP115</td>
			<td>LOOK SP115 Black Braided Silk Non absorbable surgical suture</td>
		</tr>
		<tr>
			<td>RS-5168 Botvin Forceps</td>
			<td>Roboz Surgical Instrument</td>
			<td>RS5168</td>
			<td>Forcep for surgery/ligation</td>
		</tr>
		<tr>
			<td>RS-5138 Graefe Forceps</td>
			<td>Roboz Surgical Instrument</td>
			<td>RS5138</td>
			<td>Forcep for surgery/ligation</td>
		</tr>
		<tr>
			<td>UV light for I-Bond</td>
			<td>Blast Lite By First Media</td>
			<td>BL778</td>
			<td>UV ligth for I-bond</td>
		</tr>
		<tr>
			<td>Vannas Microdissecting Scissor</td>
			<td>Roboz Surgical Instrument</td>
			<td>RS5618</td>
			<td>Scissor for ligation</td>
		</tr>
		<tr>
			<td>Vet Bond</td>
			<td>3M Vetbond</td>
			<td>1469SB</td>
			<td>Vet Glue</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>HYPOXIA</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hypoxidial</td>
			<td>Starr Life Science</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Oxygen sensor</td>
			<td>Medical Products</td>
			<td></td>
			<td>MiniOxI- oxygen analyzer/sensor for hypoxia rig</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>EEG RECORDING</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Female receptacle connector 0.079&#34;</td>
			<td>Mill-Max Manufacturing Corp</td>
			<td>832-10-024-10-001000</td>
			<td>Ordered from Digikey</td>
		</tr>
		<tr>
			<td>Grass Amplifier</td>
			<td>Natus Neurology Incorporated</td>
			<td></td>
			<td>Grass Product</td>
		</tr>
		<tr>
			<td>LabChart Pro</td>
			<td>ADI Instruments</td>
			<td></td>
			<td>Software to run the system</td>
		</tr>
		<tr>
			<td>Male Socket Connector 0.079&#34;</td>
			<td>Mill-Max Manufacturing Corp</td>
			<td>833-43-024-20-001000</td>
			<td>Ordered from Digikey</td>
		</tr>
		<tr>
			<td>Operational Amplifier</td>
			<td>Texas Instruments, Dallas, TX, USA</td>
			<td>TLC2274CD</td>
			<td>TLC2274 Quad Low&#8208;Noise Rail&#8208;to Rail Operational Amplifier</td>
		</tr>
		<tr>
			<td>Operational Amplifier</td>
			<td>Texas Instruments, Dallas, TX, USA</td>
			<td>TLC2272ACDR</td>
			<td>TLC2274 Quad Low&#8208;Noise Rail&#8208;to Rail Operational Amplifier</td>
		</tr>
		<tr>
			<td>Stainless Steel wire</td>
			<td>A-M Systems</td>
			<td>791400</td>
			<td>0.005&#34; Bare/0.008&#34; Coated 100 ft</td>
		</tr>
		<tr>
			<td>Ultra-Flexible Wire</td>
			<td>McMaster-Carr</td>
			<td>9564T1</td>
			<td>36 Gauze wire of various color</td>
		</tr>
	</tbody>
</table>

continuous video electroencephalogram during hypoxia-ischemia in neonatal mice

A isquemia de hipóxia é a causa mais comum de convulsões neonatais. Modelos animais são cruciais para a compreensão dos mecanismos e fisiologia subjacentes às convulsões neonatais e à isquemia de hipóxia. Este manuscrito descreve um método de monitoramento contínuo de eletroencefalograma de vídeo (EEG) em camundongos neonatais para detectar convulsões e analisar o fundo do EEG durante a isquemia de hipóxia. O uso de vídeo e EEG em conjunto permite a descrição da semiologia da convulsão e a confirmação de convulsões. Este método também permite a análise de espectrogramas de energia e tendências de padrão de fundo EEG durante o período de tempo experimental. Neste modelo de isquemia de hipóxia, o método permite o registro de EEG antes da lesão para obter uma linha de base normativa e durante a lesão e recuperação. O tempo total de monitoramento é limitado pela incapacidade de separar filhotes da mãe por mais de quatro horas. Embora tenhamos utilizado um modelo de convulsões hipoxica-isquêmicas neste manuscrito, este método para monitoramento de vídeo neonatais poderia ser aplicado a diversos modelos de doenças e convulsões em roedores.

Semiologia convulsiva
A exposição à hipóxia neonatal resulta em convulsões generalizadas e focais em camundongos (Figura 1A-C). Gravações de EEG de vídeo permitem que achados eletrográficos sejam correlacionados ao comportamento em vídeo. Esses comportamentos foram pontuados utilizando-se um escore de apreensão comportamental de roedores neonatais (BSS)16. Além da BSS, categorizamos eventos com base em ...

Watch this Scientific Journal Video about Continuous Video Electroencephalogram during Hypoxia-Ischemia in Neonatal Mice at JoVE.com

Continuous Video Electroencephalogram during Hypoxia-Ischemia in Neonatal Mice

Este manuscrito descreve um método para gravações contínuas de EEG de vídeo usando eletrodos de profundidade múltiplos em camundongos neonatais submetidos à hipoxia-isquemia.

Eletroencefalograma de vídeo contínuo durante hipoxia-isquemia em camundongos neonatais

Hypoxia ischemia is the most common cause of neonatal seizures. Animal models are crucial for understanding the mechanisms and physiology underlying ...

continuous-video-electroencephalogram-during-hypoxia-ischemia

Research

JoVE Journal

Neuroscience

3.3K visualizações.  University of Virginia. Este manuscrito descreve um método para gravações contínuas de EEG de vídeo usando eletrodos de profundidade múltiplos em camundongos neonatais submetidos à hipoxia-isquemia.

Vídeo: Continuous Video Electroencephalogram during Hypoxia-Ischemia in Neonatal Mice

Video-oculography in Mice

Eye movements are very important in order to track an object or to stabilize an image on the retina during movement. Animals without a fovea, such as the mouse, have a limited capacity to lock their eyes onto a target. In contrast to these target directed eye movements, compensatory ocular eye movements are easily elicited in afoveate animals1,2,3,4. Compensatory ocular movements are generated by processing vestibular and optokinetic information into a command signal that will drive the eye muscles. The processing of the vestibular and optokinetic information can be investigated separately and together, allowing the specification of a deficit in the oculomotor system. The oculomotor system can be tested by evoking an optokinetic reflex (OKR), vestibulo-ocular reflex (VOR) or a visually-enhanced vestibulo-ocular reflex (VVOR). The OKR is a reflex movement that compensates for "full-field" image movements on the retina, whereas the VOR is a reflex eye movement that compensates head movements. The VVOR is a reflex eye movement that uses both vestibular as well as optokinetic information to make the appropriate compensation. The cerebellum monitors and is able to adjust these compensatory eye movements. Therefore, oculography is a very powerful tool to investigate brain-behavior relationship under normal as well as under pathological conditions (f.e. of vestibular, ocular and/or cerebellar origin).
Testing the oculomotor system, as a behavioral paradigm, is interesting for several reasons. First, the oculomotor system is a well understood neural system5. Second, the oculomotor system is relative simple6; the amount of possible eye movement is limited by its ball-in-socket architecture ("single joint") and the three pairs of extra-ocular muscles7. Third, the behavioral output and sensory input can easily be measured, which makes this a highly accessible system for quantitative analysis8. Many behavioral tests lack this high level of quantitative power. And finally, both performance as well as plasticity of the oculomotor system can be tested, allowing research on learning and memory processes9.
Genetically modified mice are nowadays widely available and they form an important source for the exploration of brain functions at various levels10. In addition, they can be used as models to mimic human diseases. Applying oculography on normal, pharmacologically-treated or genetically modified mice is a powerful research tool to explore the underlying physiology of motor behaviors under normal and pathological conditions. Here, we describe how to measure video-oculography in mice8.

Video-oculography is a very quantitative method to investigate ocular motor performance as well as motor learning. Here, we describe how to measure video-oculography in mice. Applying this technique on normal, pharmacologically-treated or genetically modified mice is a powerful research tool to explore the underlying physiology of motor behaviors.

Vídeo oculografia-in Mice

Eye movements are very important in order to track an object or to stabilize an image on the retina during movement. Animals without a fovea, such as the ...

Neurociência

Intracerebroventricular Viral Injection of the Neonatal Mouse Brain for Persistent and Widespread Neuronal Transduction

With the pace of scientific advancement accelerating rapidly, new methods are needed for experimental neuroscience to quickly and easily manipulate gene expression in the mouse brain. Here we describe a technique first introduced by Passini and Wolfe for direct intracranial delivery of virally-encoded transgenes into the neonatal mouse brain. In its most basic form, the procedure requires only an ice bucket and a microliter syringe. However, the protocol can also be adapted for use with stereotaxic frames to improve consistency for researchers new to the technique. The method relies on the ability of adeno-associated virus (AAV) to move freely from the cerebral ventricles into the brain parenchyma while the ependymal lining is still immature during the first 12-24 hr after birth. Intraventricular injection of AAV at this age results in widespread transduction of neurons throughout the brain. Expression begins within days of injection and persists for the lifetime of the animal. Viral titer can be adjusted to control the density of transduced neurons, while co-expression of a fluorescent protein provides a vital label of transduced cells. With the rising availability of viral core facilities to provide both off-the-shelf, pre-packaged reagents and custom viral preparation, this approach offers a timely method for manipulating gene expression in the mouse brain that is fast, easy, and far less expensive than traditional germline engineering.

Here we demonstrate a technique for widespread neuronal transduction by intraventricular injection of adeno-associated virus into the neonatal mouse brain. This method provides a rapid and easy way to attain lifelong expression of virally-delivered transgenes.

Injection Viral intracerebroventricular do Neonatal do rato do cérebro para a transdução neuronal persistente e generalizada

With the pace of scientific advancement accelerating rapidly, new methods are needed for experimental neuroscience to quickly and easily manipulate gene ...

Video Imaging and Spatiotemporal Maps to Analyze Gastrointestinal Motility in Mice

The enteric nervous system (ENS) plays an important role in regulating gastrointestinal (GI) motility and can function independently of the central nervous system. Changes in ENS function are a major cause of GI symptoms and disease and may contribute to GI symptoms reported in neuropsychiatric disorders including autism. It is well established that isolated colon segments generate spontaneous, rhythmic contractions known as Colonic Migrating Motor Complexes (CMMCs). A procedure to analyze the enteric neural regulation of CMMCs in ex vivo preparations of mouse colon is described. The colon is dissected from the animal and flushed to remove fecal content prior to being cannulated in an organ bath. Data is acquired via a video camera positioned above the organ bath and converted to high-resolution spatiotemporal maps via an in-house software package. Using this technique, baseline contractile patterns and pharmacological effects on ENS function in colon segments can be compared over 3-4 hr. In addition, propagation length and speed of CMMCs can be recorded as well as changes in gut diameter and contraction frequency. This technique is useful for characterizing gastrointestinal motility patterns in transgenic mouse models (and in other species including rat and guinea pig). In this way, pharmacologically induced changes in CMMCs are recorded in wild type mice and in the Neuroligin-3R451C mouse model of autism. Furthermore, this technique can be applied to other regions of the GI tract including the duodenum, jejunum and ileum and at different developmental ages in mice.

This article describes a video imaging technique and high-resolution spatiotemporal mapping to identify changes in the neural regulation of colonic motility in adult mice. Subtle effects on gastrointestinal (GI) function can be detected using this approach in isolated tissue preparations to advance our understanding of GI disease.

Vídeo Imagem e Mapas espaço-temporais para analisar Motilidade Gastrointestinal em Ratos

The enteric nervous system (ENS) plays an important role in regulating gastrointestinal (GI) motility and can function independently of the central ...

Spinal Cord Neurons Isolation and Culture from Neonatal Mice

We present a protocol for the isolation and culture of spinal cord neurons. The neurons are obtained from neonatal C57BL/6 mice and are isolated on postnatal day 1-3. A mouse litter, usually 4-10 pups born from one breeding pair, is gathered for one experiment, and spinal cords are collected individually from each mouse after euthanasia with isoflurane. The spinal column is dissected out and then the spinal cord is released from the column. The spinal cords are then minced to increase the surface area of delivery for an enzymatic protease that allows for the neurons and other cells to be released from the tissue. Trituration is then used to release the cells into solution. This solution is subsequently fractionated in a density gradient to separate the various cells in solution, allowing for neurons to be isolated. Approximately 1-2.5 x 106 neurons can be isolated from one litter group. The neurons are then seeded onto wells coated with adhesive factors that allow for proper growth and maturation. The neurons take approximately 7 days to reach maturity in the growth and culture medium and can be used thereafter for treatment and analysis.

This study presents a technique for the isolation of neurons from WT neonatal mice. It requires the careful dissection of the spinal cord from the neonatal mouse, followed by the separation of neurons from the spinal cord tissue through mechanical and enzymatic cleavage.

Isolamento e cultura de neurônios da medula espinhal de ratos neonatais

We present a protocol for the isolation and culture of spinal cord neurons. The neurons are obtained from neonatal C57BL/6 mice and are isolated on ...

In Vivo Two-photon Imaging of Cortical Neurons in Neonatal Mice

Two-photon imaging is a powerful tool for the in vivo analysis of neuronal circuits in the mammalian brain. However, a limited number of in vivo imaging methods exist for examining the brain tissue of live newborn mammals. Herein we summarize a protocol for imaging individual cortical neurons in living neonatal mice. This protocol includes the following two methodologies: (1) the Supernova system for sparse and bright labeling of cortical neurons in the developing brain, and (2) a surgical procedure for the fragile neonatal skull. This protocol allows the observation of temporal changes of individual cortical neurites during neonatal stages with a high signal-to-noise ratio. Labeled cell-specific gene silencing and knockout can also be achieved by combining the Supernova with RNA interference and CRISPR/Cas9 gene editing systems. This protocol can, thus, be used for analyzing the developmental dynamics of cortical neurons, molecular mechanisms that control the neuronal dynamics, and changes in neuronal dynamics in disease models.

In Vivo Two-photon Imaging of Cortical Neurons in Neonatal Mice

We present an in vivo two-photon imaging protocol for imaging the cerebral cortex of neonatal mice. This method is suitable for analyzing the developmental dynamics of cortical neurons, the molecular mechanisms that control the neuronal dynamics, and the changes in neuronal dynamics in disease models.

Na Vivo Imagem de dois fotões de neurônios Cortical em camundongos Neonatais

Two-photon imaging is a powerful tool for the in vivo analysis of neuronal circuits in the mammalian brain. However, a limited number of in vivo imaging ...

Optogenetic Manipulation of Neural Circuits During Monitoring Sleep/wakefulness States in Mice

In recent years, optogenetics has been widely used in many fields of neuroscientific research. In many cases, an opsin, such as channel rhodopsin 2 (ChR2), is expressed by a virus vector in a particular type of neuronal cells in various Cre-driver mice. Activation of these opsins is triggered by application of light pulses which are delivered by laser or LED through optic cables, and the effect of activation is observed with very high time resolution. Experimenters are able to acutely stimulate neurons while monitoring behavior or another physiological outcome in mice. Optogenetics can enable useful strategies to evaluate function of neuronal circuits in the regulation of sleep/wakefulness states in mice. Here we describe a technique for examining the effect of optogenetic manipulation of neurons with a specific chemical identity during electroencephalogram (EEG) and electromyogram (EMG) monitoring to evaluate the sleep stage of mice. As an example, we describe manipulation of GABAergic neurons in the bed nucleus of the stria terminalis (BNST). Acute optogenetic excitation of these neurons triggers a rapid transition to wakefulness when applied during NREM sleep. Optogenetic manipulation along with EEG/EMG recording can be applied to decipher the neuronal circuits that regulate sleep/wakefulness states.

Here, we describe methods of optogenetic manipulation of particular types of neurons during monitoring of sleep/wakefulness states in mice, presenting our recent work on the bed nucleus of the stria terminalis as an example.

Manipulação optogenetic de circuitos neural durante a monitoração sono/Estados do wakefulness nos ratos

In recent years, optogenetics has been widely used in many fields of neuroscientific research. In many cases, an opsin, such as channel rhodopsin 2 ...

Modeling Neonatal Intraventricular Hemorrhage Through Intraventricular Injection of Hemoglobin

Neonatal intraventricular hemorrhage (IVH) is a common consequence of premature birth and leads to brain injury, posthemorrhagic hydrocephalus (PHH), and lifelong neurological deficits. While PHH can be treated by temporary and permanent cerebrospinal fluid (CSF) diversion procedures (ventricular reservoir and ventriculoperitoneal shunt, respectively), there are no pharmacological strategies to prevent or treat IVH-induced brain injury and hydrocephalus. Animal models are needed to better understand the pathophysiology of IVH and test pharmacological treatments. While there are existing models of neonatal IVH, those that reliably result in hydrocephalus are often limited by the necessity for large-volume injections, which may complicate modeling of the pathology or introduce variability in the clinical phenotype observed.
Recent clinical studies have implicated hemoglobin and ferritin in causing ventricular enlargement after IVH. Here, we develop a straightforward animal model that mimics the clinical phenotype of PHH utilizing small-volume intraventricular injections of the blood breakdown product hemoglobin. In addition to reliably inducing ventricular enlargement and hydrocephalus, this model results in white matter injury, inflammation, and immune cell infiltration in periventricular and white matter regions. This paper describes this clinically relevant, simple method for modeling IVH-PHH in neonatal rats using intraventricular injection and presents methods for quantifying ventricle size post injection.

We present a model of neonatal intraventricular hemorrhage using rat pups that mimics the pathology seen in humans.

Modelagem da Hemorragia Intraventricular Neonatal Através da Injeção Intraventricular de Hemoglobina

Neonatal intraventricular hemorrhage (IVH) is a common consequence of premature birth and leads to brain injury, posthemorrhagic hydrocephalus (PHH), and ...

<meta charset="utf8"></head><body>Mapeamento da atividade neuronal no desenvolvimento do córtex sensorial de camundongos

In Vivo Visualization of Spontaneous Activity in Neonatal Mouse Sensory Cortex at a Single-Neuron Resolution

The mammalian brain undergoes dynamic developmental changes at both the cellular and circuit levels throughout prenatal and postnatal periods. Following the discovery of numerous genes contributing to these developmental changes, it is now known that neuronal activity also substantially modulates these processes. In the developing cerebral cortex, neurons exhibit synchronized activity patterns that are specialized to each primary sensory area. These patterns markedly differ from those observed in the mature cortex, emphasizing their role in regulating area-specific developmental processes. Deficiencies in neuronal activity during development can lead to various brain diseases. These findings highlight the need to examine the regulatory mechanisms underlying activity patterns in neuronal development. This paper summarizes a series of protocols to visualize primary sensory areas and neuronal activity in neonatal mice, to image the activity of individual neurons within the cortical subfields using two-photon microscopy in vivo, and to analyze subfield-related activity correlations. We show representative results of patchwork-like synchronous activity within individual barrels in the somatosensory cortex. We also discuss various potential applications and some limitations of this protocol.

<meta charset="utf8"></head><body>Autor em destaque: decifrando a formação de circuitos neurais a partir de microscopia de dois fótons e imagens de neurônios únicos

Primary sensory areas in the neocortex exhibit unique spontaneous activities during development. This article describes how to visualize individual neuron activities and primary sensory areas to analyze area-specific synchronous activities in neonatal mice in vivo.

Visualização in vivo da atividade espontânea no córtex sensorial de camundongos neonatais com resolução de neurônio único

The mammalian brain undergoes dynamic developmental changes at both the cellular and circuit levels throughout prenatal and postnatal periods. Following ...