This research was supported by Basic Science Research Program through the NRF funded by the Ministry of Education, Science and Technology (2010-0022362) and (2012R1A2A2A02046812).

Declaração de Ética: Este experimento foi aprovado pelo Comitê Animal Care Institucional e Use o Kyungpook National University, e foi realizada de acordo com o Guia para o Cuidado e Uso de Animais de Laboratório (Instituto Nacional de Saúde, 1996). Depois de experimento, os animais foram sacrificados sob dióxido de carbono eutanásia. 1. Projeto do Bar Cabeça-fixação para ratos NOTA: Este passo é uma diretriz geral para um design de barra de fixação. Qualquer modificação sobre a dimensão e material é possível, dependendo animais ou implantes. Projetando um bar cabeça-fixação usando o software CAD é recomendado mas não necessário. <ol><li> Use um software de CAD para projetar uma barra de fixação. <ol><li> Projetar um bar fixação de uma forma retangular (123 × 35 × 6 mm) (Figura 1A). Faça um entalhe rectangular (16 × 20 mm; porta) no meio da barra de fixação. Adicionar encostas ou recuos which servir como um trilho de guia sobre as fronteiras da porta (Figura 1A-A, Figura 1B -arrows). NOTA: Certifique-se de que a área do porto cobre o retângulo prevista de crânio do rato sobre o cérebro para permitir acessos verticais utilizando um manipulador estereotáxica para a maioria das áreas do cérebro por meio de uma craniotomia. </li><li> Montar as placas (50 x 20 x 6 mm) com dois furos de fixação alongadas em ambos os lados da barra de fixação. Certifique-se de que esses buracos passar parafusos de 6 mm de diâmetro (Figura 1A-d). Fazer um buraco de 3 mm de diâmetro na frente da porta de um gancho de bloqueio (Figura 1A-b). </li><li> Faça uma caixa com um andar (135 × 305 mm) e paredes laterais (305 × 76 mm). Perfurar dois buracos de 6 mm de diâmetro, como mostrado na Figura 1A (inset). Adicionar paredes de suporte sobre a barra de fixação (Figura 1A-E). </li></ol></li><li> Fabricação a barra concebida e caixa e montar cada um deles usando como cianoacrilatomostrado na Figura 1A (inset). Monte a barra na caixa com parafusos de 6 mm de diâmetro. Aplicar inclinação, ajustando a posição do parafuso da barra de fixação de cabeça ergonômica (Figura 1A-inserção). NOTA: Para os ratos, a dimensão da barra de fixação é de 60 × 20 × 4 mm (que consiste em duas camadas de 2 mm de espessura) painéis de acrílico. A porta é quadrada de 8 mm de largura (superior) e 9 x 10 mm (inferior) tal como mostrado na Figura 1C. Placas de ancoragem são do mesmo tamanho de ratos &quot;. As paredes placa caixa e laterais são 100 × 72 milímetros e 100 × 50 mm, respectivamente. </li></ol> 2. Cabeça Mounter Construção durante cirurgia de implantação CUIDADO: Seja cauteloso ao lidar com resina acrílica dental. O líquido pode causar irritação na pele. Colocar uma máscara e usar luvas. Trabalhar em uma área bem ventilada. <ol><li> Preparação antes da cirurgia <ol><li> Enrole firmemente a fronteira do porto da barra de fixação com aparaffin película para impedir a adesão de resina acrílica aplicada à barra (ver Figura 1B e Figura 2A). Revestir a fronteira da porta coberta pela película de parafina com uma fina camada de resina acrílica. </li><li> Use instrumentos cirúrgicos esterilizados. Completamente desinfectar quadro estereotáxico e seu entorno partir de álcool etílico a 70%. </li></ol></li><li> Realizar a cirurgia de implantação estereotáxica <ol><li> Anestesiar um animal por injecção intraperitoneal de uma mistura de cocktail (2 ml / kg) de cetamina 10 ml (50 mg / ml), cloridrato de xilazina 1,5 ml (23,32 mg / ml), e 2,5 ml de solução salina. Confirme se o animal totalmente anestesiados e não responde a cauda e pitadas de dedo do pé. Injectar mistura cocktail de 1 ml / kg durante a cirurgia, quando necessário. </li><li> Corrigir o animal para o aparelho estereotáxico. Aplicar pomada oftálmica nos olhos para evitar a secura durante a cirurgia. Raspar e limpar o couro cabeludo com etanol 70%. Dê a injecção subcutânea de lidocaína a 2% e incisão no scalp ao longo da linha média do crânio. Completamente raspar periósteo. Enxaguar várias vezes com solução salina. </li><li> Faça perfuração burr-hole perto da borda do crânio. Parafusos de implante 4-5 voltas (até 1 mm) de profundidade da superfície do crânio para evitar uma violação da dura-máter. Certifique-se de nenhum vazamento de líquor e sangue na superfície do crânio após a implantação parafuso. Enxágüe com solução salina e secar a superfície do crânio usando ar-puff, especialmente em torno dos parafusos. </li><li> Revestimento de superfície do crânio com uma fina camada de &quot;cola dentária (Super-Bond C &amp; B)&quot;. Não cobrir inteiramente a superfície do crânio, incluindo o bregma se implante de eletrodos adicional está programado. Use a bregma para a marcação de coordenadas craniotomia. Eletrodos e / ou microdrive implantes e corrigi-lo no crânio através da aplicação de resina acrílica em torno dele. </li><li> Aplicar resina acrílica adicional no topo do cimento dental. Use quantidade adequada de resina acrílica de deixar espaço fill-out suficiente entre revestido por uma barra de resinaresina montagem inicial d quando fixando os parafusos e / ou eléctrodos (Figura 2A). </li></ol></li><li> Coloque bar cabeça-fixação 5 mm ou mais acima da superfície do crânio e alinhe seu centro (Figura 2A -Left). </li><li> Aplicar resina acrílica na folga entre a base do crânio e resinas iniciais de montagem. (Figura 2A -Center). Aguarde até que a resina se tornar difícil. </li><li> Remover ear-bar e puxe o montador moldado para fora da porta de bar fixação. (Figura 2A -Direita). Cuidadosamente aplicar resina acrílica adicional em torno dos trilhos da borda do montador moldado, se necessário. </li><li> Enxaguar a superfície da ferida do couro cabeludo com solução salina estéril. Injectar um antibiótico (enrofloxacina, 5 mg / kg sc) e um (tartarato de butorfanol, 2 mg / kg sc) analgésico imediatamente após a cirurgia. Abrigar o animal individualmente em uma única gaiola. </li></ol> 3. Animais habituar-a-Frente-a fixação Nota: Esta etapa deescribas horários de habituação com base em avaliações empiricamente bem-sucedidas dos autores. Para uma visão geral do processo de habituação para a cabeça-fixação, ver o trabalho de 11 de 10 Schwartz ou Guo. <ol><li> Dê período de recuperação suficiente (uma semana ou mais) para os animais. No dia 1, o manuseio de animais com freqüência em curtas sessões divididas. </li><li> No dia seguinte (Dia 2), exponha o animal ao ambiente de fixação (caixa). Não insira o seu montador cabeça na porta do bar fixação. Deixe os animais para se acostumar com o ambiente. Firmemente agarrar o montador cabeça usando a mão para 1 a 2 segundos e solte-o imediatamente. Repita fixação curto prazo com a mão-de agarrar várias vezes. </li><li> No Dia 3, os animais se habituam a cabeça-fixação. <ol><li> Trazer animais das gaiolas e liquidá-los na caixa de direção se dirige para o porto da barra de fixação. Pegue o montador cabeça e insira-o na porta do bar fixação. </li><li> Vincular o montador (animal decabeça) para o gancho de travamento da barra de fixação com uma faixa de borracha. Suporte para 5 min. NOTA: Não toque no tronco ou na cauda do animal após a fixação, o que leva o animal a ranger e luta aumentando o estresse do animal. Quando o animal continua lutando mais de 1 min, liberá-lo e tente mais tarde. A partir desta etapa, os animais mostram excreção de urina e fezes sempre que expostos a cabeça de fixação, mas isso gradualmente fica reduzida como habituação rendimentos. </li><li> Recuperar o elástico de bloqueio e ejetar o dispositivo de montagem para fora da porta. Coloque os animais de volta para a jaula de casa e prestar um pedaço de cereal ou uma semente de girassol na gaiola como uma recompensa. O próximo julgamento começa em 30 min. Repita 3.4.1 a 3.4.4 cinco ou mais dentro de um dia. </li></ol></li><li> No dia 4 a 7, expor o animal a cabeça de fixação tal como descrito no protocolo 3.4. Aumentar gradualmente a duração de fixação de cabeça (10 min, 20 min, 30 min e 50 min a habituação rendimentos). NOTA: Se os animais não fazemt alimentar a recompensa do alimento, ele pode ser um sinal de um nível elevado de stress. Não aumente o tempo de fixação. Se os animais mostram repetido lutando comportamento, habituá-los por um período mais longo. </li><li> Verifique o peso corporal do animal por dia. Considere habituação sem êxito quando o peso corporal está diminuindo. Continuar em tarefas comportamentais com fixação de cabeça depois de habituação bem sucedido. NOTA: Sucesso habituação facilita o treinamento comportamental subsequente (Figura 3E e F). </li></ol>

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The authors have nothing to disclose.

This protocol demonstrates a simple and convenient head fixation method using materials at hand. For physically successful head fixation, the first critical steps during surgery is to rinse and dry the skull surface clearly before applying the dental adhesive resin cement. Second, this method does not uses screws implanting under temporal muscles and only depends on the screws on the skull, their perpendicular implantation against the surface of skull rim is crucial10. This reduces the possibility of accidenta...

Cabeça de fixação ou de contenção da cabeça é uma técnica de imobilização da cabeça do animal, anexando uma armação ou placa sobre o crânio de fixação rígida. A técnica foi adotada para estimulação sensorial preciso, detecção comportamental com ou sem gravação neural em animais acordados 1-3 e para a rotulagem juxtacellular durante o ciclo sono-vigília 4. É também utilizado para imagiologia in vivo cérebro 5,6. Agora técnica de fixação da cabeça é uma ferramenta comumente usada em neurociência e pesquisa comportamental. Basicamente, fixação de cabeça tradicional exige fixação cirúrgica de Metal Head-posts no topo do crânio 6-8. As peças de fixação são, em seguida, fixar-se uma plataforma fixa, o que resulta na imobilização da cabeça. Investigação neurofisiológica em animais acordados como neural e / ou gravação óptica, a intervenção circuitos cerebrais, imagens do cérebro é acompanhada por cirurgia de implantação usando acrílicos odontológicos. Portanto,parece uma tarefa simples para implementar a fixação de cabeça naqueles laboratórios quando é necessário experimentalmente. Os quadros devem ser projetado para ser leve e pequeno o suficiente para não perturbar o comportamento natural do animal nas suas gaiolas. Ele também fornece rigidez mecânica quando amarrado à plataforma estacionária. Tem ainda mais a biocompatibilidade dependendo fins experimentais. Portanto, é tecnicamente difícil de projetar e fabricar tais cabeça-lugares em equipamentos de laboratório geral. Neste estudo, um método de fixação de cabeça novela é descrita, proporcionando rigidez mecânica por meio de aperto conveniente, sem recurso a grampos metálicos cabeça-mensagens. Ao utilizar o método, de fixação de cabeça pode ser feita sob condições laboratoriais gerais, em que a cirurgia de implantação é geralmente realizada em roedores para estudo do cérebro. O metal cabeça-as mensagens são substituídos com cimento acrílico moldado parcialmente resina por uma barra de fixação de cabeça feito por encomenda e o processo de moldagem é feito durante IMPLANcirurgia tação. A barra de fixação possui alta compatibilidade espacial com outros implantes, como sondas de gravação neurais, eletrodos de estimulação. Também simplifica passos de fixação da cabeça do animal na plataforma de fixação por parafuso removendo-fixação. Nós usamos esse método no estudo comportamental anterior e concluímos que este método é fácil de implementar e conveniente em experimentação prática 9.

<table border="0" cellpadding="0" cellspacing="0" width="901">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Dental acrylic resin</td>
			<td style="width:199px;">Lang Dental Manufacturing</td>
			<td style="width:129px;">Ortho-Jet</td>
			<td style="width:343px;">to make molded mounter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Paraffin film</td>
			<td style="width:199px;">Bemis</td>
			<td style="width:129px;">Parafilm</td>
			<td>to prevent adhesion of acrylic resin to the bar</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Dental adhesive</td>
			<td style="width:199px;">Sun Medical</td>
			<td style="width:129px;">Super-Bond C&#38;B</td>
			<td>to bond between acrylic resin and skull</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Plexglass or other acrylic plate</td>
			<td style="width:199px;"></td>
			<td style="width:129px;"></td>
			<td>to make fixation bar and box platform</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Cyanoacrylate</td>
			<td style="width:199px;"></td>
			<td style="width:129px;"></td>
			<td>to bond acrylic plates</td>
		</tr>
	</tbody>
</table>

acrylic resin molding based head fixation technique in rodents

Head fixation is a technique of immobilizing animal's head by attaching a head-post on the skull for rigid clamping. Traditional head fixation requires surgical attachment of metallic frames on the skull. The attached frames are then clamped to a stationary platform resulting in immobilization of the head. However, metallic frames for head fixation have been technically difficult to design and implement in general laboratory environment. In this study, we provide a novel head fixation method. Using a custom-made head fixation bar, head mounter is constructed during implantation surgery. After the application of acrylic resin for affixing implants such as electrodes and cannula on the skull, additional resins applied on top of that to build a mold matching to the port of the fixation bar. The molded head mounter serves as a guide rails, investigators conveniently fixate the animal&#8217;s head by inserting the head mounter into the port of the fixation bar. This method could be easily applicable if implantation surgery using dental acrylics is necessary and might be useful for laboratories that cannot easily fabricate CNC machined metal head-posts.

Este método de fixação de cabeça é aplicável aos ratos e camundongos. Total de oito ratos receberam implante bilateral de eletrodos de estimulação no feixe do cérebro anterior medial. Para quatro deles, personalizados eletrodos de fio de tungstênio (Microdrives) foram adicionalmente implantado em área forelimb o M1 (Figura 2C). Para ratinhos (n = 2), quatro eléctrodos de arame de aço inoxidável foram implantadas em áreas corticais frontais / occipitais. Durante a cirurgia, montadores de c...

Watch this Scientific Journal Video about Acrylic Resin Molding Based Head Fixation Technique in Rodents at JoVE.com

Acrylic Resin Molding Based Head Fixation Technique in Rodents

Traditional head fixation techniques have used metallic frames attached on the skull as an interface for head fixation apparatus. This protocol demonstrates a frameless, acrylic resin molding based head fixation technique for behavioral tasks in rodents.

Cabeça de base acrílica Resina de moldagem técnica de fixação em roedores

Head fixation is a technique of immobilizing animal's head by attaching a head-post on the skull for rigid clamping. Traditional head fixation requires ...

acrylic-resin-molding-based-head-fixation-technique-in-rodents

Research

JoVE Journal

Neuroscience

11.7K visualizações.  Kyungpook National University. Traditional head fixation techniques have used metallic frames attached on the skull as an interface for head fixation apparatus. This protocol demonstrates a frameless, acrylic resin molding based head fixation technique for behavioral tasks in rodents.

Vídeo: Acrylic Resin Molding Based Head Fixation Technique in Rodents

Preparing Undercut Model of Posttraumatic Epileptogenesis in Rodents

Partially isolated cortex ("undercut") is an animal model of posttraumatic epileptogenesis. The surgical procedure involves cutting through the sensorimotor cortex and the underneath white matter (undercut) so that a specific region of the cerebral cortex is largely isolated from the neighboring cortex and subcortical regions1-3. After a latency of two or more weeks following the surgery, epileptiform discharges can be recorded in brain slices from rodents1; and electrical or behavior seizures can be observed in vivo from other species such as cat and monkey4-6. This well established animal model is efficient to generate and mimics several important characteristics of traumatic brain injury. However, it is technically challenging attempting to make precise cortical lesions in the small rodent brain with a free hand. Based on the procedure initially established in Dr. David Prince's lab at the Stanford University1, here we present an improved technique to perform a surgery for the preparation of this model in mice and rats. We demonstrate how to make a simple surgical device and use it to gain a better control of cutting depth and angle to generate more precise and consistent results. The device is easy to make, and the procedure is quick to learn. The generation of this animal model provides an efficient system for study on the mechanisms of posttraumatic epileptogenesis.

Partially isolated cortex (&#x201C;undercut&#x201D;) is an efficient animal model of posttraumatic epileptogenesis. Here we demonstrate how to make a novel surgical device and use it to make more precise and consistent lesions to generate this model.

Preparando Modelo de rebaixo de epileptogênese Pós-Traumático em Roedores

Partially isolated cortex ("undercut") is an animal model of posttraumatic epileptogenesis. The surgical procedure involves cutting through the ...

Neurociência

Whole Animal Perfusion Fixation for Rodents

The goal of fixation is to rapidly and uniformly preserve tissue in a life-like state. While placing tissue directly in fixative works well for small pieces of tissue, larger specimens like the intact brain pose a problem for immersion fixation because the fixative does not reach all regions of the tissue at the same rate 5,7. Often, changes in response to hypoxia begin before the tissue can be preserved 12. The advantage of directly perfusing fixative through the circulatory system is that the chemical can quickly reach every corner of the organism using the natural vascular network. In order to utilize the circulatory system most effectively, care must be taken to match physiological pressures 3. It is important to note that physiological pressures are dependent on the species used. Techniques for perfusion fixation vary depending on the tissue to be fixed and how the tissue will be processed following fixation. In this video, we describe a low-cost, rapid, controlled and uniform fixation procedure using 4% paraformaldehyde perfused via the vascular system: through the heart of the rat to obtain the best possible preservation of the brain for immunohistochemistry. The main advantage of this technique (vs. gravity-fed systems) is that the circulatory system is utilized most effectively.

Here we describe a low-cost, rapid, controlled and uniform fixation procedure using 4% paraformaldehyde perfused via the vascular system: through the heart of the rat to obtain the best possible preservation of the brain.

Fixação de Perfusão todo animal para Roedores

The goal of fixation is to rapidly and uniformly preserve tissue in a life-like state. While placing tissue directly in fixative works well for small ...

Large-scale Recording of Neurons by Movable Silicon Probes in Behaving Rodents

A major challenge in neuroscience is linking behavior to the collective activity of neural assemblies. Understanding of input-output relationships of neurons and circuits requires methods with the spatial selectivity and temporal resolution appropriate for mechanistic analysis of neural ensembles in the behaving animal, i.e. recording of representatively large samples of isolated single neurons. Ensemble monitoring of neuronal activity has progressed remarkably in the past decade in both small and large-brained animals, including human subjects1-11. Multiple-site recording with silicon-based devices are particularly effective because of their scalability, small volume and geometric design.
Here, we describe methods for recording multiple single neurons and local field potential in behaving rodents, using commercially available micro-machined silicon probes with custom-made accessory components. There are two basic options for interfacing silicon probes to preamplifiers: printed circuit boards and flexible cables. Probe supplying companies (<a href="http://www.neuronexustech.com/" >http://www.neuronexustech.com/</a>; <a href="http://www.sbmicrosystems.com/">http://www.sbmicrosystems.com/</a>; <a href="http://www.acreo.se/">http://www.acreo.se/</a>) usually provide the bonding service and deliver probes bonded to printed circuit boards or flexible cables. Here, we describe the implantation of a 4-shank, 32-site probe attached to flexible polyimide cable, and mounted on a movable microdrive. Each step of the probe preparation, microdrive construction and surgery is illustrated so that the end user can easily replicate the process.

We describe methods for large-scale recording of multiple single units and local field potential in behaving rodents with silicon probes. Drive fabrication, probe attachment to the drive and probe implantation processes are illustrated in sufficient details for easy replication.

Em larga escala de gravação de Neurônios por sondas de silicone móveis em Comportando Roedores

A major challenge in neuroscience is linking behavior to the collective activity of neural assemblies. Understanding of input-output relationships of ...

Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents

When rodents have free access to a running wheel in their home cage, voluntary use of this wheel will depend on the time of day1-5. Nocturnal rodents, including rats, hamsters, and mice, are active during the night and relatively inactive during the day. Many other behavioral and physiological measures also exhibit daily rhythms, but in rodents, running-wheel activity serves as a particularly reliable and convenient measure of the output of the master circadian clock, the suprachiasmatic nucleus (SCN) of the hypothalamus. In general, through a process called entrainment, the daily pattern of running-wheel activity will naturally align with the environmental light-dark cycle (LD cycle; e.g. 12 hr-light:12 hr-dark). However circadian rhythms are endogenously generated patterns in behavior that exhibit a ~24 hr period, and persist in constant darkness. Thus, in the absence of an LD cycle, the recording and analysis of running-wheel activity can be used to determine the subjective time-of-day. Because these rhythms are directed by the circadian clock the subjective time-of-day is referred to as the circadian time (CT). In contrast, when an LD cycle is present, the time-of-day that is determined by the environmental LD cycle is called the zeitgeber time (ZT).
Although circadian rhythms in running-wheel activity are typically linked to the SCN clock6-8, circadian oscillators in many other regions of the brain and body9-14 could also be involved in the regulation of daily activity rhythms. For instance, daily rhythms in food-anticipatory activity do not require the SCN15,16 and instead, are correlated with changes in the activity of extra-SCN oscillators17-20. Thus, running-wheel activity recordings can provide important behavioral information not only about the output of the master SCN clock, but also on the activity of extra-SCN oscillators. Below we describe the equipment and methods used to record, analyze and display circadian locomotor activity rhythms in laboratory rodents.

Circadian rhythms in voluntary wheel-running activity in mammals are tightly coupled to the molecular oscillations of a master clock in the brain. As such, these daily rhythms in behavior can be used to study the influence of genetic, pharmacological, and environmental factors on the functioning of this circadian clock.

Registro e análise dos ritmos circadianos em Running rodas Atividade em Roedores

When rodents have free access to a running wheel in their home cage, voluntary use of this wheel will depend on the time of day1-5. Nocturnal rodents, ...

Transplantation of Olfactory Ensheathing Cells to Evaluate Functional Recovery after Peripheral Nerve Injury

Olfactory ensheathing cells (OECs) are neural crest cells which allow growth and regrowth of the primary olfactory neurons. Indeed, the primary olfactory system is characterized by its ability to give rise to new neurons even in adult animals. This particular ability is partly due to the presence of OECs which create a favorable microenvironment for neurogenesis. This property of OECs has been used for cellular transplantation such as in spinal cord injury models. Although the peripheral nervous system has a greater capacity to regenerate after nerve injury than the central nervous system, complete sections induce misrouting during axonal regrowth in particular after facial of laryngeal nerve transection. Specifically, full sectioning of the recurrent laryngeal nerve (RLN) induces aberrant axonal regrowth resulting in synkinesis of the vocal cords. In this specific model, we showed that OECs transplantation efficiently increases axonal regrowth.
OECs are constituted of several subpopulations present in both the olfactory mucosa (OM-OECs) and the olfactory bulbs (OB-OECs). We present here a model of cellular transplantation based on the use of these different subpopulations of OECs in a RLN injury model. Using this paradigm, primary cultures of OB-OECs and OM-OECs were transplanted in Matrigel after section and anastomosis of the RLN. Two months after surgery, we evaluated transplanted animals by complementary analyses based on videolaryngoscopy, electromyography (EMG), and histological studies. First, videolaryngoscopy allowed us to evaluate laryngeal functions, in particular muscular cocontractions phenomena. Then, EMG analyses demonstrated richness and synchronization of muscular activities. Finally, histological studies based on toluidine blue staining allowed the quantification of the number and profile of myelinated fibers.
All together, we describe here how to isolate, culture, identify and transplant OECs from OM and OB after RLN section-anastomosis and how to evaluate and analyze the efficiency of these transplanted cells on axonal regrowth and laryngeal functions.

Olfactory ensheathing cells (OECs) are neural crest cells which allow growth of the primary olfactory neurons. This specific property can be used for cellular transplantation. We present here a model of cellular transplantation based on the use of OECs in a laryngeal nerve injury model.

Transplante de células olfativas Ensheathing para avaliar a recuperação funcional após a lesão do nervo periférico

Olfactory ensheathing cells (OECs) are neural crest cells which allow growth and regrowth of the primary olfactory neurons. Indeed, the primary olfactory ...

Deep Brain Stimulation with Simultaneous fMRI in Rodents

In order to visualize the global and downstream neuronal responses to deep brain stimulation (DBS) at various targets, we have developed a protocol for using blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) to image rodents with simultaneous DBS. DBS fMRI presents a number of technical challenges, including accuracy of electrode implantation, MR artifacts created by the electrode, choice of anesthesia and paralytic to minimize any neuronal effects while simultaneously eliminating animal motion, and maintenance of physiological parameters, deviation from which can confound the BOLD signal.&#160;Our laboratory has developed a set of procedures that are capable of overcoming most of these possible issues. For electrical stimulation, a homemade tungsten bipolar microelectrode is used, inserted stereotactically at the stimulation site in the anesthetized subject. In preparation for imaging, rodents are fixed on a plastic headpiece and transferred to the magnet bore. For sedation and paralysis during scanning, a cocktail of dexmedetomidine and pancuronium is continuously infused, along with a minimal dose of isoflurane; this preparation minimizes the BOLD ceiling effect of volatile anesthetics. In this example experiment, stimulation of the subthalamic nucleus (STN) produces BOLD responses which are observed primarily in ipsilateral cortical regions, centered in motor cortex. Simultaneous DBS and fMRI allows the unambiguous modulation of neural circuits dependent on stimulation location and stimulation parameters, and permits observation of neuronal modulations free of regional bias. This technique may be used to explore the downstream effects of modulating neural circuitry at nearly any brain region, with implications for both experimental and clinical DBS.

This protocol describes a standard method for simultaneous functional magnetic resonance imaging and deep brain stimulation in the rodent. The combined use of these experimental tools allows for the exploration of global downstream activity in response to electrical stimulation at virtually any brain target.

Estimulação Cerebral Profunda com fMRI simultâneo em Roedores

In order to visualize the global and downstream neuronal responses to deep brain stimulation (DBS) at various targets, we have developed a protocol for ...

Transcranial Electrical Brain Stimulation in Alert Rodents

Transcranial electrical brain stimulation can modulate cortical excitability and plasticity in humans and rodents. The most common form of stimulation in humans is transcranial direct current stimulation (tDCS). Less frequently, transcranial alternating current stimulation (tACS) or transcranial random noise stimulation (tRNS), a specific form of tACS using an electrical current applied randomly within a pre-defined frequency range, is used. The increase of noninvasive electrical brain stimulation research in humans, both for experimental and clinical purposes, has yielded an increased need for basic, mechanistic, safety studies in animals. This article describes a model for transcranial electrical brain stimulation (tES) through the intact skull targeting the motor system in alert rodents. The protocol provides step-by-step instructions for the surgical set-up of a permanent epicranial electrode socket combined with an implanted counter electrode on the chest. By placing a stimulation electrode into the epicranial socket, different electrical stimulation types, comparable to tDCS, tACS, and tRNS in humans, can be delivered. Moreover, the practical steps for tES in alert rodents are introduced. The applied current density, stimulation duration, and stimulation type may be chosen depending on the experimental needs. The caveats, advantages, and disadvantages of this set-up are discussed, as well as safety and tolerability aspects.

This protocol describes a surgical set-up for a permanent epicranial electrode socket and an implanted chest electrode in rodents. By placing a second electrode into the socket, different types of transcranial electrical brain stimulation can be delivered to the motor system in alert animals through the intact skull.

Estimulação transcraniana de elétrica cerebral em roedores alertas

Transcranial electrical brain stimulation can modulate cortical excitability and plasticity in humans and rodents. The most common form of stimulation in ...

Intracranial Pharmacotherapy and Pain Assays in Rodents

Pain is a salient sensory experience with affective and cognitive dimensions. However, central mechanisms for pain remain poorly understood, hindering the development of effective therapeutics. Intracranial pharmacology presents an important tool for understanding the molecular and cellular mechanisms of pain in the brain, as well as for novel treatments. Here we present a protocol that integrates intracranial pharmacology with pain behavior testing. Specifically, we show how to infuse analgesic drugs into a select brain region, which may be responsible for pain modulation. Furthermore, to determine the effect of the candidate drug in the central nerve system, pain assays are performed after intracranial treatment. Our results demonstrate that intracranial administration of analgesic drugs in a targeted region can provide relief of pain in rodents. Thus, our protocol successfully demonstrates that intracranial pharmacology, combined with pain behavior testing, can be a powerful tool for the study of pain mechanisms in the brain.

Here we present a protocol to perform intracranial pharmacological experiments followed by pain behavior assays in rodents. This protocol allows researchers to deliver molecular and cellular targets in the brain, for pharmacologic agents in the treatment of pain.

Farmacoterapia intracraniana e ensaios de dor em roedores

Pain is a salient sensory experience with affective and cognitive dimensions. However, central mechanisms for pain remain poorly understood, hindering the ...

The Power of Interstimulus Interval for the Assessment of Temporal Processing in Rodents

Temporal processing deficits have been implicated as a potential elemental dimension of higher-level cognitive processes, commonly observed in neurocognitive disorders. Despite the popularization of prepulse inhibition (PPI) in recent years, many current protocols promote using a percent of control measure, thereby precluding the assessment of temporal processing. The present study used cross-modal PPI and gap prepulse inhibition (gap-PPI) to demonstrate the benefits of employing a range of interstimulus intervals (ISIs) to delineate effects of sensory modality, psychostimulant exposure, and age. Assessment of sensory modality, psychostimulant exposure, and age reveals the utility of an approach varying the interstimulus interval (ISI) to establish the shape of the ISI function, including increases (sharper curve inflections) or decreases (flattening of the response amplitude curve) in startle amplitude. Additionally, shifts in peak response inhibition, suggestive of a differential sensitivity to the manipulation of ISI, are often revealed. Thus, the systematic manipulation of ISI affords a critical opportunity to evaluate temporal processing, which may reveal the underlying neural mechanisms involved in neurocognitive disorders.

Temporal processing, a preattentive process, may underlie deficits in higher-level cognitive processes, including attention, commonly observed in neurocognitive disorders. Using prepulse inhibition as an exemplar paradigm, we present a protocol for manipulating interstimulus interval (ISI) to establish the shape of the ISI function to provide an assessment of temporal processing.

O poder do intervalo de Interstimulus para a avaliação do processamento Temporal em roedores

Temporal processing deficits have been implicated as a potential elemental dimension of higher-level cognitive processes, commonly observed in ...

A Revised Surgical Approach to Induce Endolymphatic Hydrops in the Guinea Pig

Endolymphatic hydrops is an enlargement of scala media that is most often associated with Meniere&#39;s disease, though the pathophysiologic mechanism(s) remain unclear. In order to adequately study the attributes of endolymphatic hydrops, such as the origins of low-frequency hearing loss, a reliable model is needed. The guinea pig is a&#160;good model because it hears in the low-frequency regions that are putatively affected by endolymphatic hydrops. Previous research has demonstrated that endolymphatic hydrops can be induced surgically via intradural or extradural approaches that involve drilling on the endolymphatic duct and sac. However, whether it was possible to create an endolymphatic hydrops model using an extradural approach that avoided dangerous drilling on the endolymphatic duct and sac was unknown. The objective of this study was to demonstrate a revised extradural approach to induce experimental endolymphatic hydrops at 30 days post-operatively by obliterating the endolymphatic sac and injuring the endolymphatic duct with a fine pick. The sample size consisted of seven guinea pigs. Functional measurements of hearing were made and temporal bones were subsequently harvested for histologic analysis. The approach had a success rate of 86% in achieving endolymphatic hydrops. The risk of cerebrospinal fluid leak was minimal. No perioperative deaths or injuries to the posterior semicircular canal occurred in the sample. The presented method demonstrates a safe and reliable way to induce endolymphatic hydrops at a relatively quick time point of 30 days. The clinical implications are that the presented method provides a reliable model to further explore the origins of low-frequency hearing loss that can be associated endolymphatic hydrops.

This article demonstrates an extradural approach to obliterate the guinea pig endolymphatic sac and injure the endolymphatic duct with a fine pick in order to induce experimental endolymphatic hydrops.

Uma abordagem cirúrgica revisada para induzir hidrops endoglicêsticos na Cobaia

Endolymphatic hydrops is an enlargement of scala media that is most often associated with Meniere&#39;s disease, though the pathophysiologic mechanism(s) ...