Los autores se apoyan en una investigación internacional de becas postdoctorales Fundación Cerebro (DC), la formación doctoral conceder T90 DA 022763 (MA), y el NIH subvención R01-EY017699 y NSF subvención BCS-0633281 (SK). Los autores agradecen a Randolph Blake por sus valiosos comentarios.

<ol>
	<li>Blake, R., Logothetis, N. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+competition.">Visual competition.</a> Nat. Rev. Neurosci. 3, 13-21 (2002).</li><li>Rees, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuroimaging+of+visual+awareness+in+patients+and+normal+subjects.">Neuroimaging of visual awareness in patients and normal subjects.</a> Curr. Op. Neurobiol. 11, 150-156 (2001).</li><li>Bahrami, B., Carmel, D., Walsh, V., Rees, G., Lavie, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unconscious+orientation+processing+depends+on+perceptual+load.">Unconscious orientation processing depends on perceptual load.</a> Journal of Vision. 8, 1-10 (2008).</li><li>Bahrami, B., Carmel, D., Walsh, V., Rees, G., Lavie, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+attention+can+modulate+unconscious+orientation+processing.">Spatial attention can modulate unconscious orientation processing.</a> Perception. 37, 1520-1528 (2008).</li><li>Carmel, D., Walsh, V., Lavie, N., Rees, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Right+parietal+TMS+shortens+dominance+durations+in+binocular+rivalry.">Right parietal TMS shortens dominance durations in binocular rivalry.</a> Current Biology. , .</li><li>Schurger, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+very+inexpensive+MRI-compatible+method+for+dichoptic+visual+stimulation.">A very inexpensive MRI-compatible method for dichoptic visual stimulation.</a> J. Neurosci. Methods. 177, 199-202 (2009).</li><li>Tong, F., Nakayama, K., Vaughn, J. T., Kanwisher, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Binocular+rivalry+and+visual+awareness+in+human+extrastriate+cortex.">Binocular rivalry and visual awareness in human extrastriate cortex.</a> Neuron. 21, 753-759 (1998).</li><li>Kovacs, I., Papathomas, T. V., Ming, Y., Feher, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=When+the+brain+changes+its+mind:+interocular+grouping+during+binocular+rivalry.">When the brain changes its mind: interocular grouping during binocular rivalry.</a> Proc. Natl. Acad. Sci. USA. 93, 15508-15511 (1996).</li><li>Blake, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+primer+on+binocular+rivalry,+including+current+controversies.">A primer on binocular rivalry, including current controversies.</a> Brain and Mind. 2, 5-38 (2001).</li><li>Cowey, A., Stoerig, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neurobiology+of+blindsight.">The neurobiology of blindsight.</a> Trends Neurosci. 14, 140-145 (1991).</li><li>Nasrallah, M., Carmel, D., Lavie, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Murder+she+wrote:+enhanced+sensitivity+to+negative+word+valence.">Murder she wrote: enhanced sensitivity to negative word valence.</a> Emotion. 9, 609-618 (2009).</li><li>Persaud, N., McLeod, P., Cowey, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Post-decision+wagering+objectively+measures+awareness.">Post-decision wagering objectively measures awareness.</a> Nat Neurosci. 10, 257-261 (2007).</li><li>Tsuchiya, N., Koch, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+flash+suppression+reduces+negative+afterimages.">Continuous flash suppression reduces negative afterimages.</a> Nat. Neurosci. 8, 1096-1101 (2005).</li><li>Bahrami, B., Lavie, N., Rees, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Attentional+Load+Modulates+Responses+of+Human+Primary+Visual+Cortex+to+Invisible+Stimuli.">Attentional Load Modulates Responses of Human Primary Visual Cortex to Invisible Stimuli.</a> Curr. Biol. 17, 509-513 (2007).</li><li>Wilson, H. R., Blake, R., Lee, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+of+travelling+waves+in+visual+perception.">Dynamics of travelling waves in visual perception.</a> Nature. 412, 907-910 (2001).</li><li>Meng, M., Tong, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+attention+selectively+bias+bistable+perception?+Differences+between+binocular+rivalry+and+ambiguous+figures.">Can attention selectively bias bistable perception? Differences between binocular rivalry and ambiguous figures.</a> Journal of Vision. 4, 539-551 (2004).</li></ol>

Hemos descrito la naturaleza de la rivalidad binocular, varios métodos para crear, y qué consideraciones se deben tener en cuenta cuando se utiliza. Como se detalla en la introducción, uso adecuado de la rivalidad binocular permite abordar experimentalmente preguntas sobre el locus (o loci) de la conciencia, la selección de la percepción y el procesamiento inconsciente. Para llevar a cabo esas investigaciones correctamente, sin embargo, uno debe ser consciente de los problemas tales como la importancia de mantener la convergencia estable, y, si la investigación de procesamiento inconsciente, la necesidad del uso de pantallas que van a producir la supresión completa. Al elegir el método a utilizar para crear rivalidad, es importante tener en cuenta las ventajas y desventajas de cada método. No tiene sentido, por ejemplo, en el uso de gafas rojo-azul si uno está interesado en el uso de varios colores estímulos, pero por otro lado, este método es probablemente el más fácil de usar en un escáner de resonancia magnética. Del mismo modo, un estereoscopio de espejo es una forma muy fiable de asegurar que las imágenes por separado caer en lugares correspondientes la retina, pero los ajustes individuales para cada observador y las dificultades técnicas para poner en un estereoscopio de un escáner de resonancia magnética podría hacer que este método menos atractivo para algunos los estudios. Por último, es importante estar al tanto de las características de la experiencia de la rivalidad binocular con el fin de emplear las medidas dependientes apropiado. Cuando la pregunta de investigación se refiere a los procesamientos inconscientes, verificación independiente de que los participantes eran realmente conscientes de la imagen suprimida es esencial. Cuando uno está interesado en cómo una manipulación experimental afecta a la duración de la dominación y represión, puede ser más ilustrativa para examinar la distribución (en forma de rayos gamma) de duración en lugar de sólo una medida de tendencia central como la media o la mediana, y puede ser importante para determinar si los observadores experimentados aguda o progresiva (poco a poco o como onda) la transición de la dominación. Esperamos que los investigadores interesados ​​en el empleo de este fascinante fenómeno se encuentra esta introducción útil.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Mirror stereoscope</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Prism goggles</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Red-blue or red-green cellophane goggles</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Computer monitor (optional)</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

how to create and use binocular rivalry

Cada uno de nuestros ojos normalmente ve una imagen ligeramente diferente del mundo que nos rodea. El cerebro puede combinar estas dos imágenes en una representación coherente. Sin embargo, cuando los ojos se presentan con imágenes que son tan diferentes el uno del otro, sucede algo interesante: en vez de la fusión de las dos imágenes en una percepción consciente combinado, lo que ocurre es un patrón de alteraciones perceptivas, donde domina una imagen de la conciencia mientras que el otro se suprime, se alterna el dominio entre las dos imágenes, por lo general cada pocos segundos. Este fenómeno perceptivo que se conoce como la rivalidad binocular. La rivalidad binocular se considera útil para el estudio de selección de la percepción y el conocimiento en modelos humanos y animales, porque de entrada no cambia visual de cada ojo conduce a alteraciones en la percepción visual y la percepción. Para crear un estímulo rivalidad binocular, lo único que se necesita es presentar a cada ojo una imagen diferente en el mismo lugar percibido. Hay varias maneras de hacer esto, pero los recién llegados al campo a menudo no está seguro el método que mejor se adapte a sus necesidades específicas. El propósito de este artículo es describir una serie de maneras de bajo costo y fácil de crear y utilizar la rivalidad binocular. Se detallan los métodos que no requieren equipo especializado costoso y describir las ventajas de cada método y desventajas. Los métodos descritos incluyen el uso de gafas rojo-azul, estereoscopios y gafas de espejo del prisma.

Watch this Scientific Journal Video about How to Create and Use Binocular Rivalry at JoVE.com

How to Create and Use Binocular Rivalry

La rivalidad binocular se produce cuando los ojos se presentan con diferentes imágenes en el mismo lugar: una imagen domina mientras que el otro se reprime y se alterna el dominio de forma periódica. La rivalidad es útil para la investigación de selección de la percepción y la percepción visual. A continuación se describen algunos métodos sencillos para crear y utilizar los estímulos binocular rivalidad.

Cómo crear y utilizar la rivalidad binocular

Each of our eyes normally sees a slightly different image of the world around us. The brain can combine these two images into a single coherent ...

Research

JoVE Journal

Neuroscience

75.0K vistas.  New York University. La rivalidad binocular se produce cuando los ojos se presentan con diferentes imágenes en el mismo lugar: una imagen domina mientras que el otro se reprime y se alterna el dominio de forma periódica. La rivalidad es útil para la investigación de selección de la percepción y la percepción visual. A continuación se describen algunos métodos sencillos para crear y utilizar los estímulos binocular rivalidad.

Video: How to Create and Use Binocular Rivalry

How to Build a Laser Speckle Contrast Imaging (LSCI) System to Monitor Blood Flow

Laser Speckle Contrast Imaging (LSCI) is a simple yet powerful technique that is used for full-field imaging of blood flow. The technique analyzes fluctuations in a dynamic speckle pattern to detect the movement of particles similar to how laser Doppler analyzes frequency shifts to determine particle speed. Because it can be used to monitor the movement of red blood cells, LSCI has become a popular tool for measuring blood flow in tissues such as the retina, skin, and brain. It has become especially useful in neuroscience where blood flow changes during physiological events like functional activation, stroke, and spreading depolarization can be quantified. LSCI is also attractive because it provides excellent spatial and temporal resolution while using inexpensive instrumentation that can easily be combined with other imaging modalities. Here we show how to build a LSCI setup and demonstrate its ability to monitor blood flow changes in the brain during an animal experiment.

How to Build a Laser Speckle Contrast Imaging LSCI System to Monitor Blood Flow

This video demonstrates how to build a Laser Speckle Contrast Imaging (LSCI) system that can easily be used to monitor blood flow.

Cómo construir un láser Speckle de imagen de contraste (LSCI) del sistema para monitorizar el flujo sanguíneo

Laser Speckle Contrast Imaging (LSCI) is a simple yet powerful technique that is used for full-field imaging of blood flow.  The technique analyzes ...

Investigación

Neurociencias

Isolation of Cerebrospinal Fluid from Rodent Embryos for use with Dissected Cerebral Cortical Explants

The CSF is a complex fluid with a dynamically varying proteome throughout development and in adulthood. During embryonic development, the nascent CSF differentiates from the amniotic fluid upon closure of the anterior neural tube. CSF volume then increases over subsequent days as the neuroepithelial progenitor cells lining the ventricles and the choroid plexus generate CSF. The embryonic CSF contacts the apical, ventricular surface of the neural stem cells of the developing brain and spinal cord. CSF provides crucial fluid pressure for the expansion of the developing brain and distributes important growth promoting factors to neural progenitor cells in a temporally-specific manner. To investigate the function of the CSF, it is important to isolate pure samples of embryonic CSF without contamination from blood or the developing telencephalic tissue. Here, we describe a technique to isolate relatively pure samples of ventricular embryonic CSF that can be used for a wide range of experimental assays including mass spectrometry, protein electrophoresis, and cell and primary explant culture. We demonstrate how to dissect and culture cortical explants on porous polycarbonate membranes in order to grow developing cortical tissue with reduced volumes of media or CSF. With this method, experiments can be performed using CSF from varying ages or conditions to investigate the biological activity of the CSF proteome on target cells.

The ventricular cerebrospinal fluid (CSF) bathes the neuroepithelial and cerebral cortical progenitor cells during early brain development in the embryo. Here we describe the method developed to isolate ventricular CSF from rodent embryos of different ages in order to investigate its biological function. In addition, we demonstrate our cerebral cortical explant dissection and culture technique that allows for explant growth with minimal volumes of culture medium or CSF.

Aislamiento de líquido cefalorraquídeo de embriones de roedores para su uso con disecados explantes cortical cerebral

The CSF is a complex fluid with a dynamically varying proteome throughout development and in adulthood. During embryonic development, the nascent CSF ...

Use of pHluorin to Assess the Dynamics of Axon Guidance Receptors in Cell Culture and in the Chick Embryo

During development, axon guidance receptors play a crucial role in regulating axons sensitivity to both attractive and repulsive cues. Indeed, activation of the guidance receptors is the first step of the signaling mechanisms allowing axon tips, the growth cones, to respond to the ligands. As such, the modulation of their availability at the cell surface is one of the mechanisms that participate in setting the growth cone sensitivity. We describe here a method to precisely visualize the spatio-temporal cell surface dynamics of an axon guidance receptor both in vitro and in vivo in the developing chick spinal cord. We took advantage of the pH-dependent fluorescence property of a green fluorescent protein (GFP) variant to specifically detect the fraction of the axon guidance receptor that is addressed to the plasma membrane. We first describe the in vitro validation of such pH-dependent constructs and we further detail their use in vivo, in the chick spinal chord, to assess the spatio-temporal dynamics of the axon guidance receptor of interest.

We describe here the use of a pH-sensitive green fluorescent protein variant, pHluorin, to study the spatio-temporal dynamics of axon guidance receptors trafficking at the cell surface.&#160;The pHluorin-tagged receptor is expressed both in cell culture and in vivo, using electroporation of the chick embryo.

Uso De pHluorin Para Evaluar La Dinámica De Los Receptores De Orientación Axón En El Cultivo Celular Y En El Embrión De Polluelo

During development, axon guidance receptors play a crucial role in regulating axons sensitivity to both attractive and repulsive cues. Indeed, activation ...

Use of a Caspase Multiplexing Assay to Determine Apoptosis in a Hypothalamic Cell Model

The ability to multiplex assays in studies of complex cellular mechanisms eliminates the need for repetitive experiments, provides internal controls, and decreases waste in costs and reagents. Here we describe optimization of a multiplex assay to assess apoptosis following a palmitic acid (PA) challenge in an in vitro hypothalamic model, using both fluorescent and luminescent based assays to measure viable cell counts and caspase-3/7 activity in a 96-well microtiter plate format. Following PA challenge, viable cells were determined by a resazurin-based fluorescent assay. Caspase-3/7 activity was then determined using a luminogenic substrate, DEVD, and normalized to cell number. This multiplexing assay is a useful technique for determining change in caspase activity following an apoptotic stimulus, such as saturated fatty acid challenge. The saturated fatty acid PA can increase hypothalamic oxidative stress and apoptosis, indicating the potential importance of assays such as that described here in studying the relationship between saturated fatty acids and neuronal function.

Multiplex assays can provide beneficial information for basic cellular mechanisms&#160;and eliminate waste of reagents and unnecessary repetitive experiments. We describe here a multiplex caspase-3/7 activity assay, using fluorescent- and luminescent-based methods, to determine cell viability in an in vitro hypothalamic model following oxidative challenge with palmitic acid.

El uso de una Multiplexación Ensayo de la caspasa para determinar la apoptosis en un modelo de célula hipotalámica

The ability to multiplex assays in studies of complex cellular mechanisms eliminates the need for repetitive experiments, provides internal controls, and ...

The Use of Trace Eyeblink Classical Conditioning to Assess Hippocampal Dysfunction in a Rat Model of Fetal Alcohol Spectrum Disorders

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain undergoes rapid organizational change and is similar to accelerated brain changes that occur during the third trimester in humans. This model of fetal alcohol spectrum disorders (FASDs) produces severe brain damage, mimicking the amount and pattern of binge-drinking that occurs in some pregnant alcoholic mothers. We describe the use of trace eyeblink classical conditioning (ECC), a higher-order variant of associative learning, to assess long-term hippocampal dysfunction that is typically seen in alcohol-exposed adult offspring. At 90 days of age, rodents were surgically prepared with recording and stimulating electrodes, which measured electromyographic (EMG) blink activity from the left eyelid muscle and delivered mild shock posterior to the left eye, respectively. After a 5 day recovery period, they underwent 6 sessions of trace ECC to determine associative learning differences between alcohol-exposed and control rats. Trace ECC is one of many possible ECC procedures that can be easily modified using the same equipment and software, so that different neural systems can be assessed. ECC procedures in general, can be used as diagnostic tools for detecting neural pathology in different brain systems and different conditions that insult the brain.

Trace eyeblink classical conditioning (ECC) was used to assess hippocampal-dependent associative learning in adult rats that were administered a high concentration (11.9% v/v) of alcohol during early neonatal brain development. In general, ECC procedures are sound diagnostic tools for detecting brain dysfunction across many psychological and biomedical settings.

El uso de condicionamiento de clásico de Eyeblink rastro para evaluar disfunción hipocampal en un modelo de rata de trastornos del espectro alcohólico Fetal

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain ...

How to Find Effects of Stimulus Processing on Event Related Brain Potentials of Close Others when Hyperscanning Partners

The partners of each pair must be able to pass the McGill Friendship Questionnaire without communicating. Each partner is then seated in front of a screen in one of two adjacent rooms. These rooms are separated by a glass window through which participants communicate to maintain feelings of togetherness while being fitted with the EEG cap. After checking for adequate EEG signals, the glass is covered by a curtain to prevent visual communication. Then, partners must be silent but are instructed to try to feel in the presence of their partner during the entire experiment. Just before it starts, participants are told that each of them will be presented with one image at a time and that these images will occur at the same time for both of them on their own screen. They are also instructed that, for each trial, the simultaneous images will always be different. However, unbeknownst to them, trials are randomized: only half of them are consistent with this instruction and actually include two different images. These trials form the DSC, that is, the different-stimuli condition. The other half of the trials are inconsistent with the instruction. They include two identical images and form the ISC (identical-stimuli condition). After the experiment, participants are sorted into two groups: those who reported that they felt in the presence of their partner during the majority of the trials and those who reported they did not. The impact of the stimulus processing of the partner is found by subtracting the mean voltages of the ERPs of the ISC (inconsistent with the instructions) from the ERPs of the DSC (consistent with the instructions) in at least two time windows (TWs): firstly, in the 75 to 150 ms TW, where the absolute values of these subtractions are greater, especially at right frontal sites, in those who felt in the presence of their partner than in those who did not; secondly, in the LPP time window (i.e., from 650 to 950 ms post onset), where ERPs are significantly less positive in the DSC than in the ISC in those in whom the raw results of the early (75-150ms) subtractions are negative.

This protocol describes key steps involved in assessing the sensitivity of the brain of one person to the stimulus processing of a close other by selecting pairs of partners, recording their electroencephalogram (EEG) simultaneously and computing their event-related brain potentials (ERPs).

Cómo encontrar efectos de estímulo procesamiento en eventos relacionados con cerebro potenciales de cerca otros cuando Hyperscanning socios

The partners of each pair must be able to pass the McGill Friendship Questionnaire without communicating. Each partner is then seated in front of a screen ...

Use of Synaptic Zinc Histochemistry to Reveal Different Regions and Laminae in the Developing and Adult Brain

Characterization of anatomical and functional brain organization and development requires accurate identification of distinct neural circuits and regions in the immature and adult brain. Here we describe a zinc histochemical staining procedure that reveals differences in staining patterns among different layers and brain regions. Others have utilized this procedure not only to reveal the distribution of zinc-containing neurons and circuits in the brain, but also to successfully delineate areal and laminar boundaries in the developing and adult brain in several species. Here we illustrate this staining procedure with images from developing and adult ferret brains. We reveal a zinc-staining pattern that serves as an anatomical marker of areas and layers, and can be reliably used to distinguish visual cortical areas in the developing and adult visual cortex. The main goal of this protocol is to present a histochemical method that allows the accurate identification of layers and regions in the developing and adult brain where other methods fail to do so. Secondarily, in conjunction with densitometric image analysis, this method allows one to assess the distribution of synaptic zinc to reveal potential changes throughout development. This protocol describes in detail the reagents, tools, and steps necessary to successively stain frozen brain sections. Although this protocol is described using ferret brain tissue, it can easily be adapted for use in rodents, cats, or monkeys as well as in other brain regions.

We describe a histochemical procedure that reveals characteristic laminar and areal zinc staining patterns in different brain regions. The zinc-staining pattern may be used in conjunction with other anatomical markers to reliably distinguish layers and regions in the developing and adult brain.

Uso de Zinc sináptica histoquímica para revelar las diferentes regiones y láminas en el cerebro en desarrollo y adulto

Characterization of anatomical and functional brain organization and development requires accurate identification of distinct neural circuits and regions ...

Use of In Vivo Single-fiber Recording and Intact Dorsal Root Ganglion with Attached Sciatic Nerve to Examine the Mechanism of Conduction Failure

Single-fiber recording has been a classical and effective electrophysiological technique over the last few decades because of its specific application for nerve fibers in the central and peripheral nervous systems. This method is particularly applicable to dorsal root ganglia (DRG), which are primary sensory neurons that exhibit a pseudo-unipolar structure of nervous processes. The patterns and features of the action potentials passed along axons are recordable in these neurons. The present study uses in vivo single-fiber recordings to observe the conduction failure of sciatic nerves in complete Freund&#8217;s adjuvant (CFA)-treated rats. As the underlying mechanism cannot be studied using in vivo single-fiber recordings, patch-clamp-recordings of DRG neurons are performed on preparations of intact DRG with the attached sciatic nerve. These recordings reveal a positive correlation between conduction failure and the rising slope of the after-hyperpolarization potential (AHP) of DRG neurons in CFA-treated animals. The protocol for in vivo single fiber-recordings allows the classification of nerve fibers via the measurement of conduction velocity and monitoring of abnormal conditions in nerve fibers in certain diseases. Intact DRG with attached peripheral nerve allows observation of the activity of DRG neurons in most physiological conditions. Conclusively, single-fiber recording combined with electrophysiological recording of intact DRGs is an effective method to examine the role of conduction failure during the analgesic process.

Single-fiber recording is an effective electrophysiological technique that is applicable to the central and peripheral nervous systems. Along with the preparation of intact DRG with the attached sciatic nerve, the mechanism of conduction failure is examined. Both protocols improve the understanding of the peripheral nervous system&#39;s relationship with pain.

Uso de la grabación de una sola fibra In Vivo y el ganglio de raíz dorsal intacto con nervio ciático adjunto para examinar el mecanismo de falla de conducción

Single-fiber recording has been a classical and effective electrophysiological technique over the last few decades because of its specific application for ...

Generation of Alpha-Synuclein Preformed Fibrils from Monomers and Use In Vivo

Use of the in vivo alpha-synuclein preformed fibril (&#945;-syn PFF) model of synucleinopathy is gaining popularity among researchers aiming to model Parkinson&#39;s disease synucleinopathy and nigrostriatal degeneration. The standardization of &#945;-syn PFF generation and in vivo application is critical in order to ensure consistent, robust &#945;-syn pathology. Here, we present a detailed protocol for the generation of fibrils from monomeric &#945;-syn, post-fibrilization quality control steps, and suggested parameters for successful neurosurgical injection of &#945;-syn PFFs into rats or mice. Starting with monomeric &#945;-syn, fibrilization occurs over a 7-day incubation period while shaking at optimal buffer conditions, concentration, and temperature. Post-fibrilization quality control is assessed by the presence of pelletable fibrils via sedimentation assay, the formation of amyloid conformation in the fibrils with a thioflavin T assay, and electron microscopic visualization of the fibrils. Whereas successful validation using these assays is necessary for success, they are not sufficient to guarantee PFFs will seed &#945;-syn inclusions in neurons, as such aggregation activity of each PFF batch should be tested in cell culture or in pilot animal cohorts. Prior to use, PFFs must be sonicated under precisely standardized conditions, followed by examination using electron microscopy or dynamic light scattering to confirm fibril lengths are within optimal size range, with an average length of 50 nm. PFFs can then be added to cell culture media or used in animals. Pathology detectable by immunostaining for phosphorylated &#945;-syn (psyn; serine 129) is apparent days or weeks later in cell culture and rodent models, respectively.&#160;

The goal of this article is to outline the steps required for the generation of fibrils from monomeric alpha-synuclein, subsequent quality control, and use of the preformed fibrils in vivo.

Generación de fibrillas alfa-Synucleinas preformadas de monómeros y uso in vivo

Use of the in vivo alpha-synuclein preformed fibril (&#945;-syn PFF) model of synucleinopathy is gaining popularity among researchers aiming to model ...

How to Obtain Reliable Visual Event-related Potentials in Newborns

The present study discusses the characteristics of visual event-related potentials (VEPs) and outlines methodological steps for obtaining reliable measurements in newborns. Obtaining high-quality, reliable VEPs is crucial for the early detection of abnormal development of the central nervous system in at-risk newborns, and for implementing successful early interventions. Recommendations are based on a previous study which showed that when post-conceptional age, polysomnography-identified sleep stages, and light-emitting diodes (LEDs) googles as the luminous source are controlled, no more than 4 repetitions of VEP averages are required to obtain replicable recordings, variability decreases, and reliable VEPs can be obtained. By controlling for these sources of variability and using statistical analyses, we were able to clearly and reliably identify the amplitude and latency of three main components (NII, PII and NIII) present in 100% of newborns (n = 20) during active sleep. Recording VEPs during awake states, quiet sleep and transitional sleep is not recommended because VEP morphology may differ significantly from one average to the next, leading to the risk of misleading clinical prognoses. Moreover, it is easier to obtain VEPs during active sleep because this state can be clearly and reliably identified at this stage of development, sleep cycles are short enough to allow measurements to be taken in a reasonable time, and the method does not require new o expensive equipment.

Several important points for obtaining high-quality reliable visual evoked potentials (VEPs) in newborns while minimizing variability and the risk of misleading prognoses are presented.