Se agradece al Dr. Dan Green para proporcionar aportes técnicos durante el desarrollo de estas técnicas experimentales. Este trabajo fue apoyado por el NIH Grant R01-EY016849A y el Premio de la familia Smith Nueva Investigador.

Parte I: La fabricación de electrodos de tungsteno en vidrio <ol><li> Un anillo de grafito se coloca en un vaso lleno de una solución concentrada de nitrato de sodio (0.71g/mL) e hidróxido de potasio (0.34g/mL) disuelto en agua 1, y el vaso se coloca debajo del brazo de costura de una máquina de coser modificadas . </li><li> Alambre de tungsteno (0,5 mm de diámetro de longitud, 6 cm) con cinta adhesiva en el brazo de costura para que está parcialmente sumergido (1-2cm) en la solución. </li><li> 2V se aplican a través del alambre de tungsteno uniendo un borne positivo en el brazo de costura y un cable negativo al anillo de grafito. </li><li> La máquina de coser está encendida y el alambre de tungsteno se sumerge repetidamente en la solución a un ritmo de 4 Hz ~ durante 2 minutos, que graba el metal electrolíticamente con una punta afilada. </li><li> El cable de grabado se coloca en un micromanipulador manual y el punto alineado bajo la dirección de microscópicas (40x) con el eje de una pipeta de vidrio (0,25 mm OD, 0.175mm ID) sacó a un punta de 1mm con un extractor de vidrio. Para evitar el movimiento durante la inserción de cables, el vaso está temporalmente asegurado a la platina del microscopio con masilla. </li><li> El cable está cuidadosamente avanzada en el extremo unpulled de la copa, por el hueco, ya través de la apertura de 1μm Una pequeña pieza de cristal se ve a romper la punta en el video, lo que indica un buen ajuste del tungsteno en el vaso. El cable debe extenderse alrededor de 5 a 10 mm más allá de la punta para las grabaciones de la rata de fibra óptica. </li><li> Cianoacrilato se aplica hasta el final unpulled de la copa y tras el endurecimiento de la impedancia eléctrica se mide, donde los electrodos 1MΩ generalmente funcionan mejor. </li></ol> Parte II: Configuración estereotáxica y grabaciones de Spike tren <ol><li> El sistema de visualización de estímulo se muestra en el video, junto con el aparato estereotáxico y microdrive para el posicionamiento y la reducción de los electrodos en el cerebro. </li><li> Para llevar a cabo grabaciones de la retina de la rata pico de tren está anestesiado y paralizado posteriormente. Procedimientos estándar (no ilustrado) se utilizan para la inserción quirúrgica de una cánula de la vena femoral para la administración de fármacos y la tráquea (tubo en Y) cánula de ventilación mecánica durante la parálisis. Los experimentos son terminales para el animal. </li><li> Después de los procedimientos preparatorios, el animal se coloca en la manta de calefacción y la cabeza se fija en su posición estereotáxica, como se define en el cerebro de rata atlas 2, con el oído y bares de los dientes. </li><li> La sonda rectal se inserta, que controla la manta de calefacción a través de una unidad de control homeotérmicos que mantiene la temperatura corporal a 37 º C. </li><li> Aguja de metal se utilizan como pistas para medir el electrocardiograma y el monitor de ritmo cardíaco. </li><li> La piel se abre en la parte superior del cráneo y de la intersección de las placas del cráneo (bregma) está expuesto. Un marco travesaño de diseño personalizado se encuentra en el lugar, un círculo marcado en el cráneo alrededor de begma a través de un agujero en el travesaño, el travesaño y se retira temporalmente. </li><li> El sistema estereotáxico se calibra mediante la colocación de la aguja guía en bregma. Un agujero de 5 mm se perfora en el cráneo en el lugar señalado y se retira el hueso, exponer el cerebro. Un delgado anillo de masilla se coloca alrededor de la abertura en el cráneo para formar un sello alrededor del agujero en el travesaño, que se pone en su lugar. </li><li> Si el animal ha estado en un plano estable de anestesia por un tiempo, se inyecta el medio paralítico con el fin de evitar que los movimientos oculares durante la recolección de datos. Después de la respiración se detiene el animal está con ventilación mecánica. Un programa personalizado pistas de los parámetros de ventilación y fisiológicas durante todo el experimento y el experimentador informa si la acción compensatoria es necesario que los parámetros de salir de los niveles normales. </li><li> La aguja guía se backloaded con el electrodo de tungsteno y bajó en el cerebro. Después de penetración en el cerebro del agujero que la barra esté llena de agar (no mostrado), y el conjunto de microdrive se fija a la barra transversal de la estabilidad mecánica. El electrodo de tungsteno es lentamente avanzada (2μm/sec) la aguja guía hasta que la punta es de 8 a 9 mm por debajo del cráneo, donde se encuentra el quiasma óptico. </li><li> Trenes pico perteneciente a las células ganglionares de la retina se identifican por su respuesta a estímulos visuales. Tras el aislamiento de una de fibra óptica el campo receptivo de la célula registrada se asigna en el espacio visual y sus propiedades de respuesta se caracteriza a la deriva con rejillas u otros patrones visuales de interés. La estabilidad del sistema permite la grabación de una sola unidad de varias horas 3. </li></ol> Materiales Adultos de Brown-Noruega ratas (250-400g) fueron comprados de un proveedor comercial y alojados en un mercado regulado (12/12) ciclo luz / oscuridad. La anestesia fue inducida con una inyección intraperitoneal de clorhidrato de ketamina y xilazina (70 y 2 mg / kg, respectivamente, Henry Schein Inc.) y se mantiene durante la duración de la experiment con una infusión intravenosa de ketamina y xilazina (30 y 1 mg / kg / hr) se mezcla con dextrosa, suero fisiológico, y triethiodide galamina (40 mg / kg / hr, Fischer Inc) a través de un catéter (0,13 mm OD, piezas pequeñas Inc ) en la vena femoral derecha. Galamina se incluye en la mezcla para paralizar los movimientos oculares. La velocidad de infusión de la bomba (WPI Inc) se ajustó según sea necesario para mantener un plano estable de anestesia según la evaluación de la frecuencia cardiaca y la variabilidad de la presión arterial. Después de la parálisis, el animal estaba con asistencia respiratoria mecánica (Harvard Apparatus, Modelo 683) a través de una cánula traqueal a 60-80 respiraciones / min (2 cc de volumen), con la tasa de los ajustes necesarios para mantener la final de la espiración de CO 2 medido con una línea de in- capnómetro (Novametrix Inc, Modelo 710Sp) a 30%. La temperatura corporal se regula a través de un sistema de control de manta homeotermos (Harvard Apparatus Inc). La temperatura del cuerpo, final de la espiración de la frecuencia cardíaca de CO 2, y la presión arterial fueron monitoreadas continuamente durante todo el experimento por un programa de LabVIEW. Los estímulos visuales fueron presentados en un Sony Multiscan 17e monitor CRT (promedio de luminancia de 30 cd / m 2) funcionando a 100 Hz con una resolución de 800x600 píxeles. Adquisición de datos y salida de monitor fueron controlados con software personalizado en Matlab y LabVIEW junto con un procesador de imagen de vídeo (Cambridge Research Systems Inc, Bits + +) y la caja de herramientas Psicofísica 4. El animal ve la pantalla de estímulo (40,4 x 30,2 cm) a una distancia de 16,5 cm a través de las lentes de contacto (Ocular Inc Instruments), y la solución oftálmica se aplica periódicamente durante el experimento para mantener los ojos húmedos. El campo visual accesible a la estimulación fue maximizado por revertir el montaje del animal en un aparato estereotáxico (Stoelting Co) 14cm elevado por encima de la superficie de una tabla flotante (TMC Inc) y el establecimiento de la pantalla en un trineo de diseño personalizado que se mueve sobre la mesa a lo largo de a ± 100 grados de arco de la nariz. Esto proporcionó un campo de visualización reposicionable que se extendió de 60 grados por encima y 35 grados por debajo del nivel del ojo y de ± 42 grados lateralmente desde el centro del monitor. Electodes tungsteno fueron fabricados con hilos obtenidos a partir de pequeñas piezas Inc y la costumbre de vidrio de borosilicato obtenidos a partir de Friedrich y Dimmock Inc. Una norma micropippete extractor (Sutter Instruments, modelo P-97) se utilizó para dar forma a la punta de vidrio. El probador de impedancia del electrodo fue adquirido de Bak-Electronics. Los electrodos se adelantaron con un sistema motorizado microdrive (Newport Inc, StepperMike). Electrocardiograma y las señales del nervio óptico se amplifica y se filtra con un amplificador de alta impedancia de entrada multielectrodo (FHC Inc, X-Cell 3x4). Latidos del corazón se detectaron con un discriminador de ventana (WPI Inc, Modelo 121). Potenciales de acción del nervio se detectaron y sellado de tiempo con una resolución de 0,1 ms por un discriminador digital de punta (FHC Inc, APM). El discriminador pico fue cerrada por una señal de disparo desde el procesador de imagen de vídeo para que los tiempos de pico estaban cerradas a los estímulos.

<ol>
	<li>Levick, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Another+tungsten+microelectrode.">Another tungsten microelectrode.</a> Med Biol Eng. 10 (4), 510-515 (1972).</li><li>Paxinos, G., Watson, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The rat brain in stereotaxic coordinates. , (1998).</li><li>Freeman, D. K., Heine, W. F., Passaglia, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+maintained+discharge+of+rat+retinal+ganglion+cells.">The maintained discharge of rat retinal ganglion cells.</a> Vis Neurosci. 25 (4), 535-548 (2008).</li><li>Brainard, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+psychophysics+toolbox.">The psychophysics toolbox.</a> Spat Vis. 10, 433-436 (1997).</li></ol>

Todos los procedimientos experimentales fueron aprobados por el Cuidado de Animales institucional y el empleo en la Universidad de Boston.

Grabaciones de fibra óptica es un enfoque atractivo para abordar las cuestiones experimentales sobre la codificación de información de la retina y la transmisión que requieren de un ojo intacto. Por otra parte, las propiedades de señalización de ambos ojos pueden ser estudiados en prácticamente el mismo estado fisiológico, si el electrodo se coloca en el quiasma óptico o el tracto donde se encuentra la actividad de las fibras del nervio óptico cruzados y no cruzados grabado con una penetración del electrodo. ...

single-unit in vivo recordings from the optic chiasm of rat

Información sobre el mundo visual se transmite al cerebro en las secuencias de potenciales de acción en la retina los axones de las células ganglionares que forman el nervio óptico.<em&gt; En vivo</em&gt; Grabaciones de las células ganglionares de los trenes aumento en varios modelos animales han revelado mucho de lo que se sabe sobre cómo los primeros procesos del sistema visual y codifica la información visual. Sin embargo, estas grabaciones han sido raros en uno de los modelos animales más comunes, la rata, posiblemente debido a la dificultad en la detección de picos despedido por los axones de pequeño diámetro. Los modelos de la enfermedad de la retina muchas con ratas motivar la necesidad de caracterizar las propiedades funcionales de las células ganglionares sin molestar a los ojos, al igual que intraocular o<em&gt; In vitro</em&gt; Grabaciones. En este caso, se demuestra un método para la grabación de las células ganglionares de los trenes pico del quiasma óptico de la rata anestesiada. En primer lugar, muestran cómo fabricar tungsteno en vidrio electrodos que captan la actividad eléctrica de un solo axones de las células ganglionares de la rata. Los electrodos de superar a todos los comerciales que hemos tratado. A continuación, ilustran nuestro diseño personalizado del sistema estereotáxico para<em&gt; In vivo</em&gt; Visual experimentos neurofisiológicos y nuestros procedimientos para la preparación de los animales y colocación de los electrodos, fiable y estable en el quiasma óptico.

Watch this Scientific Journal Video about Single-unit In vivo Recordings from the Optic Chiasm of Rat at JoVE.com

Single-unit In vivo Recordings from the Optic Chiasm of Rat

Las células ganglionares de la retina transmiten la información visual desde el ojo hasta el cerebro con las secuencias de potenciales de acción. En este caso, se demuestra cómo registrar los potenciales de acción de las células ganglionares de la única<em&gt; In vivo</em&gt; De ratas anestesiadas.

Una sola unidad En vivo Grabaciones de la quiasma óptico de la rata

Information about the visual world is transmitted to the brain in sequences of action potentials in retinal ganglion cell axons that make up the optic ...

single-unit-in-vivo-recordings-from-the-optic-chiasm-of-rat

Research

JoVE Journal

Neuroscience

Single-unit In vivo Recordings from the Optic Chiasm of Rat

11.6K vistas.  Boston University. Las células ganglionares de la retina transmiten la información visual desde el ojo hasta el cerebro con las secuencias de potenciales de acción. En este caso, se demuestra cómo registrar los potenciales de acción de las células ganglionares de la única In vivo De ratas anestesiadas.

Video: Single-unit In vivo Recordings from the Optic Chiasm of Rat

Retrograde Fluorescent Labeling Allows for Targeted Extracellular Single-unit Recording from Identified Neurons In vivo

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from individual neurons are critical for understanding how neural circuits function under natural conditions. Traditionally, these recordings have been performed 'blind', meaning the identity of the recorded cell is unknown at the start of the recording. Cellular identity can be subsequently determined via intracellular1, juxtacellular2 or loose-patch3 iontophoresis of dye, but these recordings cannot be pre-targeted to specific neurons in regions with functionally heterogeneous cell types. Fluorescent proteins can be expressed in a cell-type specific manner permitting visually-guided single-cell electrophysiology4-6. However, there are many model systems for which these genetic tools are not available. Even in genetically accessible model systems, the desired promoter may be unknown or genetically homogenous neurons may have varying projection patterns. Similarly, viral vectors have been used to label specific subgroups of projection neurons7, but use of this method is limited by toxicity and lack of trans-synaptic specificity. Thus, additional techniques that offer specific pre-visualization to record from identified single neurons in vivo are needed. Pre-visualization of the target neuron is particularly useful for challenging recording conditions, for which classical single-cell recordings are often prohibitively difficult8-11. The novel technique described in this paper uses retrograde transport of a fluorescent dye applied using tungsten needles to rapidly and selectively label a specific subset of cells within a particular brain region based on their unique axonal projections, thereby providing a visual cue to obtain targeted electrophysiological recordings from identified neurons in an intact circuit within a vertebrate CNS.
The most significant novel advancement of our method is the use of fluorescent labeling to target specific cell types in a non-genetically accessible model system. Weakly electric fish are an excellent model system for studying neural circuits in awake, behaving animals12. We utilized this technique to study sensory processing by "small cells" in the anterior exterolateral nucleus (ELa) of weakly electric mormyrid fish. "Small cells" are hypothesized to be time comparator neurons important for detecting submillisecond differences in the arrival times of presynaptic spikes13. However, anatomical features such as dense myelin, engulfing synapses, and small cell bodies have made it extremely difficult to record from these cells using traditional methods11, 14. Here we demonstrate that our novel method selectively labels these cells in 28% of preparations, allowing for reliable, robust recordings and characterization of responses to electrosensory stimulation.

Retrograde Fluorescent Labeling Allows for Targeted Extracellular Single-unit Recording from Identified Neurons In vivo

Retrograde transport of fluorescent dye labels a sub-population of neurons based on anatomical projection. Labeled axons can be visually targeted in vivo, permitting extracellular recording from identified axons. This technique facilitates recording when neurons cannot be labeled through genetic manipulation or are difficult to isolate using 'blind' in vivo approaches.

Marcaje fluorescente retrógrada Permite dirigida extracelular sola unidad de grabación de neuronas identificadas<em&gt; En vivo</em

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from ...

Investigación

Neurociencias

A Procedure for Implanting Organized Arrays of Microwires for Single-unit Recordings in Awake, Behaving Animals

In vivo electrophysiological recordings in the awake, behaving animal provide a powerful method for understanding neural signaling at the single-cell level. The technique allows experimenters to examine temporally and regionally specific firing patterns in order to correlate recorded action potentials with ongoing behavior. Moreover, single-unit recordings can be combined with a plethora of other techniques in order to produce comprehensive explanations of neural function. In this article, we describe the anesthesia and preparation for microwire implantation. Subsequently, we enumerate the necessary equipment and surgical steps to accurately insert a microwire array into a target structure. Lastly, we briefly describe the equipment used to record from each individual electrode in the array. The fixed microwire arrays described are well-suited for chronic implantation and allow for longitudinal recordings of neural data in almost any behavioral preparation. We discuss tracing electrode tracks to triangulate microwire positions as well as ways to combine microwire implantation with immunohistochemical techniques in order to increase the anatomical specificity of recorded results.

Implanting organized arrays of microwires for use in single-unit electrophysiological recordings presents a number of technical challenges.&#160;Methods for performing this technique and the equipment necessary are described.&#160;Also, the beneficial use of organized microwire arrays to record from distinct neural subregions with high spatial selectivity is discussed.

Un procedimiento para la implantación de matrices Organizados de Microhilos para grabaciones de una sola unidad en Awake, Comportarse Animales

In vivo electrophysiological recordings in the awake, behaving animal provide a powerful method for understanding neural signaling at the single-cell ...

A Guide to In vivo Single-unit Recording from Optogenetically Identified Cortical Inhibitory Interneurons

A major challenge in neurophysiology has been to characterize the response properties and function of the numerous inhibitory cell types in the cerebral cortex. We here share our strategy for obtaining stable, well-isolated single-unit recordings from identified inhibitory interneurons in the anesthetized mouse cortex using a method developed by Lima and colleagues1. Recordings are performed in mice expressing Channelrhodopsin-2 (ChR2) in specific neuronal subpopulations. Members of the population are identified by their response to a brief flash of blue light. This technique &#8211; termed &#8220;PINP&#8221;, or Photostimulation-assisted Identification of Neuronal Populations &#8211; can be implemented with standard extracellular recording equipment. It can serve as an inexpensive and accessible alternative to calcium imaging or visually-guided patching, for the purpose of targeting extracellular recordings to genetically-identified cells. Here we provide a set of guidelines for optimizing the method in everyday practice. We refined our strategy specifically for targeting parvalbumin-positive (PV+) cells, but have found that it works for other interneuron types as well, such as somatostatin-expressing (SOM+) and calretinin-expressing (CR+) interneurons.

A Guide to In vivo Single-unit Recording from Optogenetically Identified Cortical Inhibitory Interneurons

Here we describe our strategy for obtaining stable, well-isolated single-unit recordings from identified inhibitory interneurons in the anesthetized mouse cortex. Neurons expressing ChR2 are identified by their response to blue light. The method uses standard extracellular recording equipment, and serves as an inexpensive alternative to calcium imaging or visually-guided patching.

Una guía para<em&gt; En vivo</em&gt; Single-unidad de grabación de Optogenetically Identificado cortical inhibitorio interneuronas

A major challenge in neurophysiology has been to characterize the response properties and function of the numerous inhibitory cell types in the cerebral ...

Visual Evoked Potential Recording in a Rat Model of Experimental Optic Nerve Demyelination

The visual evoked potential (VEP) recording is widely used in clinical practice to assess the severity of optic neuritis in its acute phase, and to monitor the disease course in the follow-up period. Changes in the VEP parameters closely correlate with pathological damage in the optic nerve. This protocol provides a detailed description about the rodent model of optic nerve microinjection, in which a partial demyelination lesion is produced in the optic nerve. VEP recording techniques are also discussed. Using skull implanted electrodes, we are able to acquire reproducible intra-session and between-session VEP traces. VEPs can be recorded on individual animals over a period of time to assess the functional changes in the optic nerve longitudinally. The optic nerve demyelination model, in conjunction with the VEP recording protocol, provides a tool to investigate the disease processes associated with demyelination and remyelination, and can potentially be employed to evaluate the effects of new remyelinating drugs or neuroprotective therapies.

Focal demyelination is induced in the optic nerve using lysolecithin microinjection. Visual evoked potentials are recorded via skull electrodes implanted over the visual cortex to examine the signal conduction along the visual pathway in vivo. This protocol details the surgical procedures underlying electrode implantation and optic nerve microinjection.

Grabación de potencial evocado visual en un modelo de rata de Experimental del Nervio Óptico Desmielinización

The visual evoked potential (VEP) recording is widely used in clinical practice to assess the severity of optic neuritis in its acute phase, and to ...

Determination of Photoreceptor Cell Spectral Sensitivity in an Insect Model from In Vivo Intracellular Recordings

Intracellular recording is a powerful technique used to determine how a single cell may respond to a given stimulus. In vision research, intracellular recording has historically been a common technique used to study sensitivities of individual photoreceptor cells to different light stimuli that is still being used today. However, there remains a dearth of detailed methodology in the literature for researchers wishing to replicate intracellular recording experiments in the eye. Here we present the insect as a model for examining eye physiology more generally. Insect photoreceptor cells are located near the surface of the eye and are therefore easy to reach, and many of the mechanisms involved in vision are conserved across animal phyla. We describe the basic procedure for in vivo intracellular recording of photoreceptor cells in the eye of a butterfly, with the goal of making this technique more accessible to researchers with little prior experience in electrophysiology. We introduce the basic equipment needed, how to prepare a live butterfly for recording, how to insert a glass microelectrode into a single cell, and finally the recording procedure itself. We also explain the basic analysis of raw response data for determining spectral sensitivity of individual cell types. Although our protocol focuses on determining spectral sensitivity, other stimuli (e.g., polarized light) and variations of the method are applicable to this setup.

Determination of Photoreceptor Cell Spectral Sensitivity in an Insect Model from In Vivo Intracellular Recordings

The electrophysiological technique of intracellular recording is demonstrated and used to determine spectral sensitivities of single photoreceptor cells in the compound eye of a butterfly.

Determinación de los fotorreceptores de la célula de sensibilidad espectral en un modelo de insectos<em&gt; En Vivo</em&gt; registros intracelulares

Intracellular recording is a powerful technique used to determine how a single cell may respond to a given stimulus. In vision research, intracellular ...

Acute In Vivo Electrophysiological Recordings of Local Field Potentials and Multi-unit Activity from the Hyperdirect Pathway in Anesthetized Rats

Converging evidence shows that many neuropsychiatric diseases should be understood as disorders of large-scale neuronal networks. To better understand the pathophysiological basis of these diseases, it is necessary to precisely characterize in which way the processing of information is disturbed between the different neuronal parts of the circuit. Using extracellular in vivo electrophysiological recordings, it is possible to accurately delineate neuronal activity within a neuronal network. The application of this method has several advantages over alternative techniques, e.g., functional magnetic resonance imaging and calcium imaging, as it allows a unique temporal and spatial resolution and does not rely on genetically engineered organisms. However, the use of extracellular in vivo recordings is limited since it is an invasive technique that cannot be universally applied. In this article, a simple and easy to use method is presented with which it is possible to simultaneously record extracellular potentials such as local field potentials and multiunit activity at multiple sites of a network. It is detailed how a precise targeting of subcortical nuclei can be achieved using a combination of stereotactic surgery and online analysis of multi-unit recordings. Thus, it is demonstrated, how a complete network such as the hyperdirect cortico-basal ganglia loop can be studied in anesthetized animals in vivo.

Acute In Vivo Electrophysiological Recordings of Local Field Potentials and Multi-unit Activity from the Hyperdirect Pathway in Anesthetized Rats

In this study, the methodology is presented on how to perform multi-site in vivo electrophysiological recordings from the hyperdirect pathway under urethane anesthesia.

Agudo<em&gt; In Vivo</em&gt; Grabaciones electrofisiológicas de potenciales de campo locales y actividad de múltiples unidades de la vía hiperdirecta en ratas anestesiadas

Converging evidence shows that many neuropsychiatric diseases should be understood as disorders of large-scale neuronal networks. To better understand the ...

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 ...

Investigating Object Representations in the Macaque Dorsal Visual Stream Using Single-unit Recordings

Previous studies have shown that neurons in parieto-frontal areas of the macaque brain can be highly selective for real-world objects, disparity-defined curved surfaces, and images of real-world objects (with and without disparity) in a similar manner as described in the ventral visual stream. In addition, parieto-frontal areas are believed to convert visual object information into appropriate motor outputs, such as the pre-shaping of the hand during grasping. To better characterize object selectivity in the cortical network involved in visuomotor transformations, we provide a battery of tests intended to analyze the visual object selectivity of neurons in parieto-frontal regions.

A detailed protocol to analyze object selectivity of parieto-frontal neurons involved in visuomotor transformations is presented.

Investigar las representaciones de objeto en la corriente Visual Dorsal de macacos usando grabaciones de una sola unidad

Previous studies have shown that neurons in parieto-frontal areas of the macaque brain can be highly selective for real-world objects, disparity-defined ...

Construction and Implementation of Carbon Fiber Microelectrode Arrays for Chronic and Acute In Vivo Recordings

Multichannel electrode arrays offer insight into the working brain and serve to elucidate neural processes at the single-cell and circuit levels. Development of these tools is crucial for understanding complex behaviors and cognition and for advancing clinical applications. However, it remains a challenge to densely record from cell populations stably and continuously over long time periods. Many popular electrodes, such as tetrodes and silicon arrays, feature large cross-diameters that produce damage upon insertion and elicit chronic reactive tissue responses associated with neuronal death, hindering the recording of stable, continuous neural activity. In addition, most wire bundles exhibit broad spacing between channels, precluding simultaneous recording from a large number of cells clustered in a small area. The carbon fiber microelectrode arrays described in this protocol offer an accessible solution to these concerns. The study provides a detailed method for fabricating carbon fiber microelectrode arrays that can be used for both acute and chronic recordings in vivo. The physical properties of these electrodes make them ideal for stable and continuous long-term recordings at high cell densities, enabling the researcher to make robust, unambiguous recordings from single units across months.

Construction and Implementation of Carbon Fiber Microelectrode Arrays for Chronic and Acute In Vivo Recordings

This protocol describes a procedure for constructing carbon fiber microelectrode arrays for chronic and acute in vivo electrophysiological recordings in mouse (Mus musculus) and ferret (Mustela putorius furo) from multiple brain regions. Each step, following the purchase of raw carbon fibers to microelectrode array implantation, is described in detail, with emphasis on microelectrode array construction.

Construcción e implementación de matrices de microelectrodos de fibra de carbono para grabaciones in vivo crónicas y agudas

Multichannel electrode arrays offer insight into the working brain and serve to elucidate neural processes at the single-cell and circuit levels. ...

In Vivo Methods to Assess Retinal Ganglion Cell and Optic Nerve Function and Structure in Large Animals

The optic nerve collects axons signals from the retinal ganglion cells and transmits visual signal to the brain. Large animal models of optic nerve injury are essential for translating novel therapeutic strategies from rodent models to clinical application due to their closer similarities to humans in size and anatomy. Here we describe some in vivo methods to evaluate the function and structure of the retinal ganglion cells (RGCs) and optic nerve (ON) in large animals, including visual evoked potential (VEP), pattern electroretinogram (PERG) and optical coherence tomography (OCT). Both goat and non-human primate were employed in this study. By presenting these in vivo methods step by step, we hope to increase experimental reproducibility among different labs and facilitate the usage of large animal models of optic neuropathies.

In Vivo Methods to Assess Retinal Ganglion Cell and Optic Nerve Function and Structure in Large Animals

Here we demostrate several in vivo tests (flash visual evoked potential, pattern electroretinogram and optic coherence tomography) in goat and rhesus macaque to understand the structure and function of the optic nerve and its neurons.

In vivo Métodos para evaluar la función y estructura de las células ganglionares de la retina y el nervio óptico en animales grandes

The optic nerve collects axons signals from the retinal ganglion cells and transmits visual signal to the brain. Large animal models of optic nerve injury ...