Con el apoyo de KIST Grant (2E21510), Nacional de Honor del programa científico del Ministerio de Educación y el Programa de Investigación de Tecnología original de la ciencia del cerebro a través de la Fundación Nacional de Investigación de Corea financiado por el Ministerio de Educación, Ciencia y Tecnología (2,010 a 0.018.944).

1. Resumen C57BL/6J - 129S4/SvJae ratones híbridos (12 ~ 15 semanas de edad) son anestesiados con ketamina (120 mg / kg ip) y xilazina (6 mg / kg, ip) de cóctel. Pellizcar la cola o del pie precede a la cirugía para inspeccionar la profundidad de la anestesia. El ratón es fijado por un aparato estereotáxico (David Kopf Instruments, modelo 902, California, EE.UU.). El cuero cabelludo se realiza una incisión en la línea media de unos 25 mm para exponer el cráneo en el tratamiento de lidocaína para reducir el dolor. Todos los residuos en el cráneo es borrado por puntas de algodón empapada en solución salina para mejorar la adherencia de los electrodos en el cráneo. Los puntos de bregma y lambda están marcadas y establecidas en el mismo plano horizontal. La poliamida amplia base de microelectrodos (PBM-matriz) se coloca de modo que su línea media vertical cumple con la línea media del cráneo. El punto de bregma debe estar ubicado en el centro de la capa de 5 º de la parte anterior del PBM-matriz. Dos o tres microtornillos se utilizan en el espacio nulo en el borde del cráneo para ayudar a asegurar la posición de los electrodos con cemento dental. Para apuntalar el conector PBM-matriz, la posición de un puntal en el centro de la cabeza, y se cubre con cemento dental. Después de curar, la piel incisión se sutura, y al menos 5 días se dan para la recuperación. Durante la recuperación, los ratones son alojadas en jaulas individuales con libre acceso a comida y agua. Después de la recuperación, el registro EEG se lleva a cabo. Los procedimientos de cuidado de los animales, quirúrgicos y de grabación estaban en conformidad con las directrices para el Cuidado de Animales institucional y el empleo, a raíz de la Ley 1992 del Reglamento de Corea del Cuidado de Animales de Laboratorio y las directrices correspondientes. Las matrices de PBM-en este manuscrito fueron fabricados como se describe por Choi. et. al 1. Póngase en contacto con los autores de la misma PBM-matriz en el video. 2. Procedimiento <ol><li> Preparar los instrumentos esterilizados y aparatos estereotáxica. </li><li> Anestesiar el ratón con la anestesia (por ejemplo, la ketamina / xilazina con una dosis de 120 y 60 mg / kg ip, respectivamente). Pellizcar la cola o del pie precede a la cirugía para inspeccionar la profundidad de la anestesia. </li><li> Monte el ratón sobre el aparato estereotáxico mediante la colocación de barras de oído en el conducto auditivo del ratón y apretando en su lugar. Los ojos se pueden cubrir con la jalea biocompatible (por ejemplo, la jalea de petróleo) para mantener los ojos se sequen por la luz de la cirugía. Después de la hidratación cabeza del ratón con el 70% de etanol, se afeitan el pelo de su cabeza. </li><li> Incisión en la cabeza cerca de 25 mm con un cuero cabelludo. Es recomendable aplicar una pequeña cantidad de clorhidrato de lidocaína al 2% en el cuero cabelludo. Pellizcar la piel con pinzas de micro (Herramientas Artes Ciencias (EE.UU.), Inc., 18052-03, California, EE.UU.) para mantener la incisión abierta. </li><li> Limpie cualquier resto de tejido que queda en el cráneo con una solución salina, torundas de algodón empapadas mejorar la adherencia de la PBM-matriz a la cabeza. El uso de peróxido para eliminar el residuo de la membrana es también eficaz. </li><li> Encontrar el bregma y lambda puntos en el cráneo, y marcarlos con un lápiz marcador a base de aceite. Coloque el PBM-matriz de modo que su línea media vertical cumple con la línea media del cráneo, como se muestra en la Figura 1. La posición del bregma en el centro de la capa de 5 º de la parte anterior del PBM-matriz con una gota de agua del grifo. Limpiar el electrodo de la película de medial a lateral con cuidado para una mejor adherencia. Con el fin de ayudar al electrodo de película estrecha palo en el cráneo, el electrodo de película debe estar completamente seco en el cráneo. El electrodo de película aún no se ha fijado en el cráneo de van der Waals fuerza. Cuando el cambio de posición del electrodo, una gota de agua de la llave es necesaria para evitar que el electrodo está roto. <img src="/files/ftp_upload/2562/2562fig1.jpg" alt="Figura 1" /> Figura 1. (Izquierda) Una PBM-matriz en el cráneo del ratón. El eje anterio-posterior del PBM-serie coincide con la línea entre el bregma (BP) y los puntos de lambda (LP). (Derecha) La posición de los electrodos en la superficie del supuesto cerebro del ratón. La anatomía del ratón están segmentados de la base de datos 3-D MRI atlas digital de un cerebro de ratón adulto C57BL/6J producidos en el Laboratorio Nacional de Brookhaven y la ubicación de electrodos están marcados de acuerdo a la medición estereotáxica. Suelo (G) y referencia (Ref) electrodos están marcados en la figura de la derecha. </li><li> Marque por lo menos tres posiciones en el área abierta del cráneo, y luego hacer los agujeros en los lugares con un taladro dental para la colocación de los microtornillos de apoyo. Estos microtornillos tienen un papel de puntal y mecánicamente apoyar el cemento dental en el cráneo. Precaución adicional que se necesita durante la perforación. Desde el cráneo del ratón se compone de capas finas, la hemorragia puede ocurrir fácilmente durante la perforación. Cuando la hemorragia ocurre, deje de taladrar y aplicar una pequeña cantidad de polvo hemostático en el agujero. </li><li> Aplique el cemento acrílico dental (Vertex-Dental, Vertex auto-curación, Países Bajos) para cubrir el PBM-matriz, tornillos de anclaje, y el resto del cráneo. Preparar el cemento dental en una c pegajoso y viscosoONDICIÓN. </li><li> Posición de un palo rígido como un puntal en el centro de la cabeza con pegamento fuerte (por ejemplo, Loctite, Henkel Loctite Corporation, Dublín, Irlanda). Ponga cinta de doble cara adhesiva en la parte trasera del avión conector. Manipular la posición del conector PBM-serie para conectar con la punta de la costilla. La distancia vertical entre el cráneo y el conector debe ser superior a 5 mm. Pegue el plano del conector y la punta de la vara con pegamento fuerte para una mejor adherencia. </li><li> Asegúrese de que el cemento dental es completamente curado. A continuación, aplique el cemento dental de acrílico sobre el cráneo y la parte trasera del avión conector para asegurar el conector en el cráneo. </li><li> Retire las abrazaderas de micro. Sutura una incisión de piel con costuras de fibra esterilizada. Quitar el ratón del aparato. Usted puede aplicar el cemento acrílico dental adicional para proteger el cráneo al descubierto. Aplicar un antibiótico (pomada fucidin, Dong Wha Farmacia, Corea del Sur) en todo el cemento y la piel suturada. </li><li> Coloque el ratón en una jaula esterilizada hasta que recupere su peso original (aproximadamente de 5 a 7 días). Se recomienda no introducir los compañeros de jaula. </li><li> Después de la recuperación, conectar el ratón por una ligera placa de circuito impreso (PCB), conector de la caja de entrada de un sistema de amplificador multicanal EEG (SynAmps 2, Carolina del Norte, EE.UU.) en su propia jaula. Las líneas de conexión debe ser tratada con cuidado para que no se enrede. </li><li> Después de 1 hora de habituación, de realizar la grabación del EEG. Exploración 4.4. (Carolina del Norte, EE.UU.), adquisición de software se utilizó en este experimento. Un conjunto de traza en tiempo típico de ratón EEG se muestra en la Figura 2. Se recomienda registrar el vídeo a relacionar el comportamiento del ratón. </li><li> Señal obtenida puede ser analizado por MATLAB (The Mathworks, Natick, MA, EE.UU.) para producir el mapa topográfico del cerebro. Topografías muestra de mapa de potencia del EEG del cerebro del ratón se muestran en la Figura 3. </li></ol> 3. Resultados representante Si por encima de los procedimientos quirúrgicos son realizados correctamente, la grabación de 40 canales de EEG del ratón se realizó con éxito, sin canales de malo. Siguientes figuras muestran el representante rastros EEG y mapas topográficos. <img src="/files/ftp_upload/2562/2562fig2.jpg" alt="Figura 2" /> Figura 2. Un seguimiento de la muestra de convulsiones EEG ausencia experimentando inducida por la inyección γ-butirolactona (GBL, 50mg/kg, ip). Barra roja indica punta-onda y descargas (SWDs) durante la crisis de ausencia. Los ejes horizontales y verticales indican el tiempo y la tensión, respectivamente. El número sigue al montaje de los canales definidos en la figura. 1 (derecha). <img src="/files/ftp_upload/2562/2562fig3.jpg" alt="Figura 3" /> Figura 3. Los mapas topográficos indica la distribución 06/02 Hz el poder. El valor de la barra de colores representa la escala de colores del mapa de poder. Durante el pico de la onda y descargas (SWDs) inducido por γ-butirolactona (GBL, 50mg/kg, ip), el poder en las regiones corticales frontoparietal grandes aumentan significativamente en comparación con el poder antes de la inyección GBL (nivel básico).

<ol>
	<li>Choi, J. H., Koch, K. P., Poppendieck, W., Lee, M., Shin, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+resolution+Electroencephalography+in+Freely+Moving+Mice.">High resolution Electroencephalography in Freely Moving Mice.</a> J Neurophysiol. , .</li><li>Lee, M., Shin, H. S., Choi, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+recording+of+brain+activity+and+functional+connectivity+in+the+mouse+brain.">Simultaneous recording of brain activity and functional connectivity in the mouse brain.</a> Conf Proc IEEE Eng Med Biol Soc. , 2934-2936 (2009).</li></ol>

Aquí mostramos los procedimientos quirúrgicos y el registro de la adquisición de EEG de alta densidad en los ratones se mueven libremente. Este método nos permite obtener mapas funcionales cerebrales a partir del modelo de ratón para estudiar los mecanismos moleculares de 1,2 espontánea rítmica o actividades relacionados con eventos cerebro. Adquisición de todos los canales en el PBM-matriz es una condición necesaria para obtener la cartografía de todo el cerebro, sin embargo hacer un contacto seguro para cada canal es muy difícil. Para mantener el contacto constante del canal en el cráneo, los siguientes procedimientos se encuentran para ser importante. En primer lugar, los restos de tejido en el cráneo puede establecer además el electrodo de la cabeza. Por lo tanto es muy importante eliminar todos los restos de tejido con hisopos de algodón esterilizado y seco hasta la superficie del cráneo. En segundo lugar, la capacidad de PBM-array que puede pegarse a la superficie del cráneo se van der Waals fuerza. Se sugiere que se aplique una gota de agua del grifo en el cráneo para construir una capa de agua antes de aplicar PBM-matriz a la cabeza. En tercer lugar, la viscosidad del cemento dental es muy importante. Si es demasiado líquido, puede crear una capa aislante bajo la PBM-matriz. Si es demasiado densa, el cemento dental fácilmente se vendrá abajo en el cráneo debido a su propio peso. Por último, por lo menos tres microtornillos de apoyo deben ser implantados en el cráneo para que el cemento dental fuertemente unida al cráneo. Los microtornillos apoyo sostener el cemento dental y asegurar la headstage, que es esencial para el estudio a largo plazo. La aplicación de PBM-matriz se limita a estudio crónico con ratones adultos debido a su tamaño y peso. Basándonos en nuestra experiencia, los ratones de más de 25 g son adecuadas para su uso. Como otras aplicaciones, a través del espacio nulo entre las ramas de nuestro PBM-matriz, se puede introducir electrodos secundarios para la grabación o el propósito de estimulación.

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high-density eeg recordings of the freely moving mice using polyimide-based microelectrode

Electroencefalograma (EEG) indica el promedio de la actividad eléctrica de las poblaciones neuronales a nivel de gran escala. Es ampliamente utilizado como una herramienta de monitorización no invasiva del cerebro en la neurociencia cognitiva, así como una herramienta de diagnóstico para los trastornos de la epilepsia y el sueño en neurología. Sin embargo, el mecanismo subyacente de la generación del ritmo EEG está todavía bajo el velo. Introducido recientemente poliamida basado en microelectrodo (PBM-array) para el ratón de alta resolución EEG 1 es uno de los ensayos para responder a las preguntas sobre las señales neurofisiológicas EEG sobre la base de una riqueza genética que contiene el modelo de ratón para el análisis del complejo proceso de generación de EEG. Esta aplicación de nanofabricados PBM-array al cráneo del ratón es una herramienta eficiente para la recolección a gran escala la actividad cerebral de ratones transgénicos y tiene capacidad para identificar las correlaciones neurales de ciertos ritmos EEG en relación con el comportamiento. Sin embargo, su diseño ultra-fino espesor y la estructura bifurcada causar problemas en el manejo e implantación de PBM-matriz. En el video presentado, los pasos de preparación y la cirugía para la implantación del PBM-array en un cráneo del ratón se describen paso a paso. Consejos sobre la manipulación y la cirugía para ayudar a los investigadores tener éxito en la implantación también se proporcionan.

Watch this Scientific Journal Video about High-density EEG Recordings of the Freely Moving Mice using Polyimide-based Microelectrode at JoVE.com

High-density EEG Recordings of the Freely Moving Mice using Polyimide-based Microelectrode

En este artículo se describe el procedimiento de la cirugía y el manejo de consejos para la implantación de ultra-delgada serie de microelectrodos de poliamida basado en (PBM-matriz) en el cráneo del ratón para la adquisición de alta densidad encefalografía (EEG) en un modelo murino.

Alta densidad de registros de EEG de los ratones se mueven libremente con poliamida basado microelectrodos

Electroencephalogram (EEG) indicates the averaged electrical activity of the neuronal populations on a large-scale level. It is widely utilized as a ...

high-density-eeg-recordings-freely-moving-mice-using-polyimide-based

Nanyang Technological University

Research

JoVE Journal

Neuroscience

36.9K vistas.  Korea Institute of Science and Technology (KIST). En este artículo se describe el procedimiento de la cirugía y el manejo de consejos para la implantación de ultra-delgada serie de microelectrodos de poliamida basado en (PBM-matriz) en el cráneo del ratón para la adquisición de alta densidad encefalografía (EEG) en un modelo murino.

Video: High-density EEG Recordings of the Freely Moving Mice using Polyimide-based Microelectrode

Combining Computer Game-Based Behavioural Experiments With High-Density EEG and Infrared Gaze Tracking

Experimental paradigms are valuable insofar as the timing and other parameters of their stimuli are well specified and controlled, and insofar as they yield data relevant to the cognitive processing that occurs under ecologically valid conditions. These two goals often are at odds, since well controlled stimuli often are too repetitive to sustain subjects' motivation. Studies employing electroencephalography (EEG) are often especially sensitive to this dilemma between ecological validity and experimental control: attaining sufficient signal-to-noise in physiological averages demands large numbers of repeated trials within lengthy recording sessions, limiting the subject pool to individuals with the ability and patience to perform a set task over and over again. This constraint severely limits researchers' ability to investigate younger populations as well as clinical populations associated with heightened anxiety or attentional abnormalities. Even adult, non-clinical subjects may not be able to achieve their typical levels of performance or cognitive engagement: an unmotivated subject for whom an experimental task is little more than a chore is not the same, behaviourally, cognitively, or neurally, as a subject who is intrinsically motivated and engaged with the task. A growing body of literature demonstrates that embedding experiments within video games may provide a way between the horns of this dilemma between experimental control and ecological validity. The narrative of a game provides a more realistic context in which tasks occur, enhancing their ecological validity (Chaytor &amp; Schmitter-Edgecombe, 2003). Moreover, this context provides motivation to complete tasks. In our game, subjects perform various missions to collect resources, fend off pirates, intercept communications or facilitate diplomatic relations. In so doing, they also perform an array of cognitive tasks, including a Posner attention-shifting paradigm (Posner, 1980), a go/no-go test of motor inhibition, a psychophysical motion coherence threshold task, the Embedded Figures Test (Witkin, 1950, 1954) and a theory-of-mind (Wimmer &amp; Perner, 1983) task. The game software automatically registers game stimuli and subjects' actions and responses in a log file, and sends event codes to synchronise with physiological data recorders. Thus the game can be combined with physiological measures such as EEG or fMRI, and with moment-to-moment tracking of gaze. Gaze tracking can verify subjects' compliance with behavioural tasks (e.g. fixation) and overt attention to experimental stimuli, and also physiological arousal as reflected in pupil dilation (Bradley et al., 2008). At great enough sampling frequencies, gaze tracking may also help assess covert attention as reflected in microsaccades - eye movements that are too small to foveate a new object, but are as rapid in onset and have the same relationship between angular distance and peak velocity as do saccades that traverse greater distances. The distribution of directions of microsaccades correlates with the (otherwise) covert direction of attention (Hafed &amp; Clark, 2002).

Procedures for recording high-density EEG and gaze data during computer game-based cognitive tasks are described. Using a video game to present cognitive tasks enhances ecological validity without sacrificing experimental control.

La combinación de PC del juego basado en experimentos del comportamiento de alta densidad de seguimiento de mirada EEG e infrarrojo

Experimental paradigms are valuable insofar as the timing and other parameters of their stimuli are well specified and controlled, and insofar as they ...

Investigación

Neurociencias

Recording Single Neurons' Action Potentials from Freely Moving Pigeons Across Three Stages of Learning

While the subject of learning has attracted immense interest from both behavioral and neural scientists, only relatively few investigators have observed single-neuron activity while animals are acquiring an operantly conditioned response, or when that response is extinguished. But even in these cases, observation periods usually encompass only a single stage of learning, i.e. acquisition or extinction, but not both (exceptions include protocols employing reversal learning; see Bingman&#160;et al.1 for an example). However, acquisition and extinction entail different learning mechanisms and are therefore expected to be accompanied by different types and/or loci of neural plasticity.
Accordingly, we developed a behavioral paradigm which institutes three stages of learning in a single behavioral session and which is well suited for the simultaneous recording of single neurons&#39; action potentials. Animals are trained on a single-interval forced choice task which requires mapping each of two possible choice responses to the presentation of different novel visual stimuli (acquisition). After having reached a predefined performance criterion, one of the two choice responses is no longer reinforced (extinction). Following a certain decrement in performance level, correct responses are reinforced again (reacquisition). By using a new set of stimuli in every session, animals can undergo the acquisition-extinction-reacquisition process repeatedly. Because all three stages of learning occur in a single behavioral session, the paradigm is ideal for the simultaneous observation of the spiking output of multiple single neurons. We use pigeons as model systems, but the task can easily be adapted to any other species capable of conditioned discrimination learning.

Learning new stimulus-response associations engages a wide range of neural processes which are ultimately reflected in changing spike output of individual neurons. Here we describe a behavioral protocol allowing for the continuous registration of single-neuron activity while animals acquire, extinguish, and reacquire a conditioned response within a single experimental session.

Grabación Potenciales de Acción Individual Neuronas &quot;de que se mueven libremente Palomas en sus Tres Etapas del Aprendizaje

While the subject of learning has attracted immense interest from both behavioral and neural scientists, only relatively few investigators have observed ...

Recording EEG in Freely Moving Neonatal Rats Using a Novel Method

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such as epilepsy and neurodegenerative disorders. However, it is technically difficult to obtain EEG recordings in neonates as it requires specialized handling and great care. Here, we present a novel method to record EEG in neonatal rat pups (P8-P15). We designed a simple and reliable electrode using computer pin loci; it can be easily implanted into the skull of a rat pup to record high-quality EEG signals in the normal and epileptic brain. Pups were given an intraperitoneal (i.p.) injection of the neurotoxin kainic acid (KA) to induce epileptic seizures. The surgical implantation performed in this procedure is less expensive than other EEG procedures for neonates. This method allows one to record high-quality and stable EEG signals for more than 1 week. Furthermore, this procedure can also be applied to adult rats and mice to study epilepsy or other neurological disorders.

Here, we introduce a novel technique designed to record electroencephalography (EEG) in freely moving neonatal epileptic pups and describe its procedures, features, and applications. This method allows one to record EEG for more than 1 week.

Grabación de EEG en Ratas Neonatales que se mueven libremente usando un método nuevo

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such ...

Visual Evoked Potential Recordings in Mice Using a Dry Non-invasive Multi-channel Scalp EEG Sensor

For scalp EEG research environments with laboratory mice, we designed a dry-type 16 channel EEG sensor which is non-invasive, deformable, and re-usable because of the plunger-spring-barrel structural facet and mechanical strengths resulting from metal materials. The whole process for acquiring the VEP responses in vivo from a mouse consists of four steps: (1) sensor assembly, (2) animal preparation, (3) VEP measurement, and (4) signal processing. This paper presents representative measurements of VEP responses from multiple mice with a submicro-voltage signal resolution and sub-hundred millisecond temporal resolution. Although the proposed method is safer and more convenient compared to other previously reported animal EEG acquiring methods, there are remaining issues including how to enhance the signal-to-noise ratio and how to apply this technique with freely moving animals. The proposed method utilizes easily available resources and shows a repetitive VEP response with a satisfactory signal quality. Therefore, this method could be utilized for longitudinal experimental studies and reliable translational research exploiting non-invasive paradigms.

We designed a dry-type 16 channel EEG sensor which is non-invasive, deformable, and re-usable. This paper describes the whole process from manufacturing the proposed EEG electrode to signal processing of visual evoked potential (VEP) signals measured on a mouse scalp using a dry non-invasive multi-channel EEG sensor.

Grabaciones de potenciales evocadas visuales en ratones usando un multicanal no invasivo seco del cuero cabelludo EEG Sensor

For scalp EEG research environments with laboratory mice, we designed a dry-type 16 channel EEG sensor which is non-invasive, deformable, and re-usable ...

Simultaneous Recordings of Cortical Local Field Potentials, Electrocardiogram, Electromyogram, and Breathing Rhythm from a Freely Moving Rat

Monitoring the physiological dynamics of the brain and peripheral tissues is necessary for addressing a number of questions about how the brain controls body functions and internal organ rhythms when animals are exposed to emotional challenges and changes in their living environments. In general experiments, signals from different organs, such as the brain and the heart, are recorded by independent recording systems that require multiple recording devices and different procedures for processing the data files. This study describes a new method that can simultaneously monitor electrical biosignals, including tens of local field potentials in multiple brain regions, electrocardiograms that represent the cardiac rhythm, electromyograms that represent awake/sleep-related muscle contraction, and breathing signals, in a freely moving rat. The recording configuration of this method is based on a conventional micro-drive array for cortical local field potential recordings in which tens of electrodes are accommodated, and the signals obtained from these electrodes are integrated into a single electrical board mounted on the animal's head. Here, this recording system was improved so that signals from the peripheral organs are also transferred to an electrical interface board. In a single surgery, electrodes are first separately implanted into the appropriate body parts and the target brain areas. The open ends of all of these electrodes are then soldered to individual channels of the electrical board above the animal's head so that all of the signals can be integrated into the single electrical board. Connecting this board to a recording device allows for the collection of all of the signals into a single device, which reduces experimental costs and simplifies data processing, because all data can be handled in the same data file. This technique will aid the understanding of the neurophysiological correlates of the associations between central and peripheral organs.

This study introduces a method for the simultaneous recording of local field potentials in the brain, electrocardiograms, electromyograms, and breathing signals of a freely moving rat. This technique, which reduces experimental costs and simplifies data analysis, will contribute to the understanding of the interactions between the brain and peripheral organs.

Grabaciones simultáneas de potenciales de campo Local Cortical, Electrocardiograma, electromiograma y respirar a ritmo de una rata libremente móvil

Monitoring the physiological dynamics of the brain and peripheral tissues is necessary for addressing a number of questions about how the brain controls ...

Noninvasive EEG Recordings from Freely Moving Piglets

The method allows the recording of high-quality electroencephalograms (EEGs) from freely moving piglets directly in the pigpen. We use a one-channel telemetric electroencephalography system in combination with standard self-adhesive hydrogel electrodes. The piglets are calmed down without the use of sedatives. After their release into the pigpen, the piglets behave normally&#8212;they drink and sleep in the same cycle as their siblings. Their sleep phases are used for the EEG recordings.

Here, we present a protocol to record telemetric electroencephalograms (EEGs) from freely moving piglets directly in the pigpen without the use of a sedative, making it possible to record typical EEG patterns during non-REM sleep, like spindle bursts.

Grabaciones de EEG no invasivo se mueva libremente lechones

The method allows the recording of high-quality electroencephalograms (EEGs) from freely moving piglets directly in the pigpen. We use a one-channel ...

Microdialysis of Excitatory Amino Acids During EEG Recordings in Freely Moving Rats

Microdialysis is a well-established neuroscience technique that correlates the changes of neurologically active substances diffusing into the brain interstitial space with the behavior and/or with the specific outcome of a pathology (e.g., seizures for epilepsy). When studying epilepsy, the microdialysis technique is often combined with short-term or even long-term video-electroencephalography (EEG) monitoring to assess spontaneous seizure frequency, severity, progression and clustering. The combined microdialysis-EEG is based on the use of several methods and instruments. Here, we performed in vivo microdialysis and continuous video-EEG recording to monitor glutamate and aspartate outflow over time, in different phases of the natural history of epilepsy in a rat model. This combined approach allows the pairing of changes in the neurotransmitter release with specific stages of the disease development and progression. The amino acid concentration in the dialysate was determined by liquid chromatography. Here, we describe the methods and outline the principal precautionary measures one should take during in vivo microdialysis-EEG, with particular attention to the stereotaxic surgery, basal and high potassium stimulation during microdialysis, depth electrode EEG recording and high-performance liquid chromatography analysis of aspartate and glutamate in the dialysate. This approach may be adapted to test a variety of drug or disease induced changes of the physiological concentrations of aspartate and glutamate in the brain. Depending on the availability of an appropriate analytical assay, it may be further used to test different soluble molecules when employing EEG recording at the same time.

Here, we describe a method for in vivo microdialysis to analyze aspartate and glutamate release in the ventral hippocampus of epileptic and non-epileptic rats, in combination with EEG recordings. Extracellular concentrations of aspartate and glutamate may be correlated with the different phases of the disease.

Microdiálisis de aminoácidos excitatorios durante las grabaciones de EEG en mover libremente las ratas

Microdialysis is a well-established neuroscience technique that correlates the changes of neurologically active substances diffusing into the brain ...

Long-term Sensory Conflict in Freely Behaving Mice

Long-term sensory conflict protocols are a valuable means of studying motor learning. The presented protocol produces a persistent sensory conflict for experiments aimed at studying long-term learning in mice. By permanently wearing a device fixed on their heads, mice are continuously exposed to a sensory mismatch between visual and vestibular inputs while freely moving in home cages. Therefore, this protocol readily enables the study of the visual system and multisensory interactions over an extended timeframe that would not be accessible otherwise. In addition to lowering the experimental costs of long-term sensory learning in naturally behaving mice, this approach accommodates the combination of in vivo and in vitro experiments. In the reported example, video-oculography is performed to quantify the vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) before and after learning. Mice exposed to this long-term sensory conflict between visual and vestibular inputs presented a strong VOR gain decrease but exhibited few OKR changes. Detailed steps of device assembly, animal care, and reflex measurements are hereby reported.

The presented protocol produces a persistent sensory conflict for experiments aimed at studying long-term learning. By permanently wearing a fixed device on their heads, mice are continuously exposed to a sensory mismatch between visual and vestibular inputs while freely moving in home cages.

A largo plazo conflicto sensorial en comportarse libremente ratones

Long-term sensory conflict protocols are a valuable means of studying motor learning. The presented protocol produces a persistent sensory conflict for ...

Hybrid Microdrive System with Recoverable Opto-Silicon Probe and Tetrode for Dual-Site High Density Recording in Freely Moving Mice

Multi-regional neural recordings can provide crucial information to understanding fine-timescale interactions between multiple brain regions. However, conventional microdrive designs often only allow use of one type of electrode to record from single or multiple regions, limiting the yield of single-unit or depth profile recordings. It also often limits the ability to combine electrode recordings with optogenetic tools to target pathway and/or cell type specific activity. Presented here is a hybrid microdrive array for freely moving mice to optimize yield and a description of its fabrication and reuse of the microdrive array. The current design employs nine tetrodes and one opto-silicon probe implanted in two different brain areas simultaneously in freely moving mice. The tetrodes and the opto-silicon probe are independently adjustable along the dorsoventral axis in the brain to maximize the yield of unit and oscillatory activities. This microdrive array also incorporates a set-up for light, mediating optogenetic manipulation to investigate the regional- or cell type-specific responses and functions of long-range neural circuits. In addition, the opto-silicon probe can be safely recovered and reused after each experiment. Because the microdrive array consists of 3D-printed parts, the design of microdrives can be easily modified to accommodate various settings. First described is the design of the microdrive array and how to attach the optical fiber to a silicon probe for optogenetics experiments, followed by fabrication of the tetrode bundle and implantation of the array into a mouse brain. The recording of local field potentials and unit spiking combined with optogenetic stimulation also demonstrate feasibility of the microdrive array system in freely moving mice.

This protocol describes the construction of a hybrid microdrive array that allows implantation of nine independently adjustable tetrodes and one adjustable opto-silicon probe in two brain regions in freely moving mice. Also demonstrated is a method for safely recovering and reusing the opto-silicon probe for multiple purposes.

Sistema microdrive híbrido con sonda de optosilicio recuperable y tetroda para grabación de alta densidad de doble sitio en ratones en movimiento libre

Multi-regional neural recordings can provide crucial information to understanding fine-timescale interactions between multiple brain regions. However, ...

Multi-Fiber Photometry to Record Neural Activity in Freely-Moving Animals

Recording the activity of a group of neurons in a freely-moving animal is a challenging undertaking. Moreover, as the brain is dissected into smaller and smaller functional subgroups, it becomes paramount to record from projections and/or genetically-defined subpopulations of neurons. Fiber photometry is an accessible and powerful approach that can overcome these challenges. By combining optical and genetic methodologies, neural activity can be measured in deep brain structures by expressing genetically-encoded calcium indicators, which translate neural activity into an optical signal that can be easily measured. The current protocol details the components of a multi-fiber photometry system, how to access deep brain structures to deliver and collect light, a method to account for motion artifacts, and how to process and analyze fluorescent signals. The protocol details experimental considerations when performing single and dual color imaging, from either single or multiple implanted optic fibers.

This protocol details how to implement and perform multi-fiber photometry recordings, how to correct for calcium-independent artifacts, and important considerations for dual-color photometry imaging.

Fotometría multifibra para registrar la actividad neuronal en animales en movimiento libre

Recording the activity of a group of neurons in a freely-moving animal is a challenging undertaking. Moreover, as the brain is dissected into smaller and ...