Gli autori desiderano ringraziare il Dr. Candace Hsieh per suggerimenti e assistenza con le tecniche di imaging e Dr. Doris Wu consultare esperti di anatomia dell&#39;orecchio interno pulcino durante l&#39;embriogenesi precoce. Questo lavoro è stato sostenuto da NSF IOS-0642346, NIH-DC010775 T32, T32-NIH GM008620, NIH R01-DC010796, e il DOE GAANN P200A120165.

1. Preparare i seguenti strumenti di dissezione e reagenti <ul><li> Fluido cerebrospinale artificiale (aCSF, 130 mM NaCl, 3 mM KCl, 1,2 mM KH 2 PO 4, 20 mM NaHCO 3, 3 mM di HEPES, 10 mM di glucosio, 2 mM CaCl 2, 1,3 mM MgSO 4) continuo infuso con 95% O 2/5% di CO 2 a temperatura ambiente. Per l&#39;infusione, riempire per 2/3 da 500 ml a bocca larga vaso Nalgene con un foro nel coperchio. Serbatoio sarà collegato mediante la tubazione di un calice gorgogliatore, che penetra la aCSF attraverso il foro nel coperchio vaso. Regolare la pressione per ottenere un flusso costante di bolle che raggiungono circa 1/3 del liquido, ma non sono abbastanza forte da causare spruzzi sul bordo. Submerge 5 ml fiale di vetro (fino a 6) nel vaso Nalgene per separare campioni singoli da loro e dalla turbolenza del flusso di gas. ACSF dovrebbe essere ossigenato per almeno 20 minuti prima di qualsiasi incubazione tessuto. </li><li> Piccolo dissezione piatto in silicone (35 mm x 10mm rivestito Petri utilizzando Sylgard elastomero Kit) con due perni dissezione inseriti in piccolo polistirolo esagonale inferiore (47 mm) peso barca. </li><li> Due fine-tip pinza, una curva punta pinze, da 50 becher ml, e un contenitore per i rifiuti del tessuto. </li><li> Tirato micropipetta di vetro (1,2 OD / 0,9 ID) spezzato a circa 20-50 micron apertura in punta e riempito con rodamina destrano ammina (RDA, MW = 3000, Invitrogen) in una soluzione di 6,25% con 0,4% Triton X-100 in PBS . Collegare con un tubo in bene per picospritzer e stabilizzare a micromanipolatore. </li></ul> 2. Micro-dissezione per svelare Papilla basilare a E8 4,5 <ol><li> Con pinze curve, tagliare E8 embrione appena sotto il tronco cerebrale, mettendo la testa direttamente sulla siliconata piatto dissezione all&#39;interno pesare barca. </li><li> Con perni dissezione, posizionare la testa con una vista ventrale così l&#39;orecchio sul lato di interesse è leggermente visibile, la testa leggermente inclinata dorsalmente e puntando 10-30 gradi di distanza dal center (Figura 2A). Immediatamente fissare la testa con perni. Se bilaterale analisi è desiderato, il centro della testa a 0 gradi, o una visione completa ventrale in modo da entrambi i lati è possibile accedere. Analogamente, per un lato sinistro iniezione, bloccare la testa a -10 a -30 gradi dal centro in modo che il lato sinistro è accessibile. </li><li> Con i 50 becher ml, trasferire 30 ml di aCSF ossigenata nel piatto, sommergendo completamente il tessuto. </li><li> Afferrare con delicatezza e la buccia verso il basso la mascella inferiore con punta fine pinze, quindi rimuovere la palpebra inferiore sul lato di interesse. </li><li> Rimuovere il tessuto vascolare sovrastante, compresa qualsiasi palato rimanente e gola. Questi tessuti molli dovrebbero staccarsi rivelando la superficie liscia di sviluppare chondrocranium con le arterie vertebrali distintivi sulla sua superficie. Da questo punto, la caratteristica massa bianca otoconial dovrebbe essere visibile. </li><li> Sezionare con cura la pelle intorno al meato esterno, cartilagine della mandibola e l&#39;orecchio medio, lasciando il diNER orecchio intatto. Utilizzare le pinze per tagliare delicatamente via queste strutture cartilaginee. </li><li> Rimuovere le arterie vertebrali e una pozza di sangue con un movimento gentile con le punte sottili pinze. Il sangue può oscurare vista e la coagulazione può collegare l&#39;apertura pipetta di iniezione. </li><li> Il condotto cocleare con adiacente epitelio sensoriale (basilare papilla) e ganglio acustico si trova direttamente sotto la chondrocranium 6 e può essere visualizzato come una forma allungata oa forma di dita proiezione si estende dall&#39;orecchio interno ventralmente, con la punta più distale (apice) in prossimità del anteriore linea mediana 5. Ci può essere un raggruppamento di sangue (rosso) dalla dissezione e / o calcificazioni otolitici (bianco) all&#39;apice del condotto cocleare (Figura 2B) che possono aiutare nella visualizzazione. Al vertice è la macula lagenar, una patch sensoriale pensato per essere della funzione vestibolare 7,8. </li></ol> 3. Etichettatura selettiva di CN VIII Fibre uditiva <ol><li&gt; Posizionare la pipetta di iniezione vicino alla superficie dell&#39;embrione nella regione cocleare papilla condotto e basilare. </li><li> Abbassare lentamente la micropipetta per forare prima il cranio. Questa regione cranica è più sottile di aree circostanti e richiede meno forza per penetrare. La micropipetta dovrebbe essere all&#39;interno del canale cocleare. Opzionale: una piccola iniezione di tracciabilità colorante può essere fatto qui per aiutare a visualizzare la papilla basilare. </li><li> Senza il riposizionamento della micropipetta, continuare ad abbassare fino a quando incomincia viola il confine profondo del condotto cocleare (Figura 1). Effettuare un&#39;iniezione qui e ripetere in più regioni lungo la lunghezza della papilla basilare (figure 2C, 2D), escludendo la punta più prossimale in cui si trova il lagena vestibolare. Con il picospritzer impostata tra 10-30 psi, diverse iniezioni sono fatte. Il volume del fluido iniettato colorante varia e dipende dal grado desiderato di etichettatura. Ogni iniezione dovrebbe portare a un colorante fluorescente-laposto Beled di circa 200-400 micron di diametro (Figura 2D). </li><li> Una volta che l&#39;iniezione è terminata, usare il forcipe per transetto il campione al di sopra del tronco cerebrale e utilizzare una pipetta di trasferimento per posizionare la porzione caudale in un piccolo vaso all&#39;interno del contenitore di aCSF continuamente perfuso con il 95% O 2/5% di CO 2. </li><li> Per ciascun embrione, 20-30 min per consentire il trasferimento di colore, a seconda della distanza del centro di traccia desiderata. </li><li> Rimuovere il tessuto e prepararsi per il sezionamento istologico. Nell&#39;esempio qui illustrato, il tessuto viene immerso in paraformaldeide al 4% (in 1X PBS) overnight, saccarosio 30% (in 1X PBS) per una notte. </li></ol> 4. Di contrasto e analisi <ol><li> Di contrasto è utile per contribuire a orientare l&#39;osservatore a localizzazione anatomica, nonché identificare le regioni di particolare interesse. Un contrasto efficace in questa preparazione è immunomarcatura neurofilamenti (figure 1, 3B, 3E), cui L fortementeAbels assoni e permette di demarcazione di tratti assonali nel SNC. </li><li> Analisi deve essere eseguita in tutta la regione etichettata, come le sporgenze possono estendere diverse centinaia di micron o più lungo l&#39;asse rostrocaudale. Alcuni esempi di analisi di base sono: tassi di errore di targeting, i tempi e / o modifiche divergenza di modelli di proiezione. Assoni RDA-etichettati sono visualizzati nel sistema nervoso centrale e periferico ad alta risoluzione (figure 3A, 3D). </li></ol>

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Studi di sviluppo precoce del nervo VIII sono stati limitati, in parte a causa della difficoltà di identificare assoni embrionali derivanti da più gangli distinti. Diversi studi hanno esplorato i segnali molecolari che guidano uditivo e vestibolare delle cellule sensoriali e destini delle cellule ganglionari durante lo sviluppo iniziale, 5,11,12 ma i processi che regolano innervazione centrale devono ancora essere determinati. Rapporti di proiezioni acustiche cellule gangliari di solito descrivere i process...

<table border="1"><tbody><tr><td> Nome del reagente / materiale </td><td> Azienda </td><td> Numero di catalogo </td><td> Commenti </td></tr><tr><td> Polistirene Pesare </td><td> Fisher Scientific </td><td> 02-202-101 </td><td></td></tr><tr><td> Petri Dish, 35 X 10 mm </td><td> Fisher Scientific </td><td> 50820644 </td><td> Utilizzare per eseguire la dissezione piatto in silicone </td></tr><tr><td> Sylgard silicone elastomero Kit </td><td> Mondo Strumenti di precisione </td><td> SYLG184 </td><td> Cappotto Petri di fare piatto dissezione </td></tr><tr><td> Dissezione Pins </td><td> Vario </td><td></td><td> Tiene embrione in atto durante la dissezione </td></tr><tr><td> NaCl </td><td> Vario </td><td></td><td> parte della ricetta aCSF </td></tr><tr><td> KCl </td><td> Vario </td><td></td><td> parte della ricetta aCSF </td&gt; </tr><tr><td> KH 2 PO 4 </td><td> Vario </td><td></td><td> parte della ricetta aCSF </td></tr><tr><td> NaHCO 3 </td><td> Vario </td><td></td><td> parte della ricetta aCSF </td></tr><tr><td> Glucosio </td><td> Vario </td><td></td><td> parte della ricetta aCSF </td></tr><tr><td> CaCl 2 </td><td> Vario </td><td></td><td> parte della ricetta aCSF </td></tr><tr><td> MgSO4 </td><td> Vario </td><td></td><td> parte della ricetta aCSF </td></tr><tr><td> Contenitore per aCSF. Suggerisci traslucido bocca larga Nalgene vaso, 500 ml (16 oz) con coperchio. </td><td> CPLabSafety </td><td> QP-PLC-03717 </td><td> Drill foro di apertura nella parte superiore del coperchio per stelo in vetro bubling liquido di penetrare </td></tr><tr><td> Vuoto flaconcino da 5 ml di vetro o comparabili flacone trasparente </td><td> American Pharmaceutical Partners, Inc </td><td> 6332300105 </td><td&gt; Uso durante l&#39;incubazione aCSF mantenere i campioni separati l&#39;uno dall&#39;altro e dal ruscello </td></tr><tr><td> Serbatoio di CarboGen (95% O 2/5% di CO 2) connesso con un tubo di gorgogliatore </td><td> Vario </td><td></td><td> Collegare con un tubo di vetro gorgogliatore staminali per infusione in aCSF </td></tr><tr><td> Calice gorgogliatore </td><td> Vario </td><td></td><td> Per infondere CarboGen in aCSF </td></tr><tr><td> Curvo-punta pinza </td><td> Mondo Strumenti di precisione </td><td> 501008 </td><td> Per rimuovere la testa dell&#39;embrione da uova </td></tr><tr><td> Due fine-tip pinza </td><td> Mondo Strumenti di precisione </td><td> 501985 </td><td> Per micro-dissezione </td></tr><tr><td> 50 ml Beaker </td><td> vario </td><td></td><td></td></tr><tr><td> Rodamina destrano Amine (RDA) </td><td> Invitrogen </td><td> vario </td><td> Tracciante fluorescente assone </td></tr><tr><td> Triton X-100 </td><td> ICN Biomedicals </td><td></td><td></td></tr><tr><td> Soluzione tampone fosfato, (1X PBS) </td><td> Vario </td><td></td><td> Lab reagente standard </td></tr><tr><td> Sottile parete di vetro capillari, 1.2 OD, ID 0,9 4 &quot;(100 mm) Lunghezza </td><td> Mondo Strumenti di precisione </td><td> TW120F-4 </td><td> Caricare con RDA. Ogni capillare fa due micropipette di vetro </td></tr><tr><td> Ago / Pipettare estrattore </td><td> David Kopf Instruments </td><td> Modello 720 </td><td> Impostazioni usate: Calore 16.4, solenoide 2,2 </td></tr><tr><td> Picospritzer </td><td> Parker Instrumentation </td><td> vario </td><td> Collegare con un tubo sottile al vetro micropipetta </td></tr><tr><td> Micromanipolatore </td><td> Narishige </td><td> vario </td><td></td></tr><tr><td> Microscopio a dissezione con fluorescenza </td><td> Vario </td><td></td><td></td&gt; </tr><tr><td> Paraformaldeide al 4% </td><td> Vario </td><td></td><td> Lab reagente standard </td></tr><tr><td> anticorpo anti-Neurofilament, opzionale </td><td> Millipore </td><td> AB1991 </td><td> Seguire il protocollo istologico raccomandato dal produttore </td></tr><tr><td> Criostato e materiali associati per sezionamento </td><td> Leica </td><td> vario </td><td></td></tr><tr><td> Microscopio epifluorescente per l&#39;imaging </td><td> Zeiss, varie </td><td></td><td></td></tr></tbody></table>

selective tracing of auditory fibers in the avian embryonic vestibulocochlear nerve

Il pulcino embrionale è un modello ampiamente utilizzato per lo studio delle proiezioni gangliari periferiche e centrali cellulari. Nel sistema uditivo, etichettatura selettiva degli assoni uditivi all&#39;interno del nervo cranico VIII aumenterebbe lo studio dello sviluppo del circuito uditivo centrale. Questo approccio è impegnativo, perché di vari organi sensoriali dell&#39;orecchio interno contribuiscono al nervo VIII 1. Inoltre, marcatori che distinguono affidabile uditivo rispetto vestibolari gruppi di assoni all&#39;interno del nervo VIII aviaria devono ancora essere identificati. Vie uditive e vestibolari non si distinguono funzionalmente in embrioni precoci, come-sensoriali evocate risposte non sono presenti prima che i circuiti sono formati. Centrale sporgenti assoni dei nervi dell&#39;VIII sono stati rintracciati in alcuni studi, ma uditivo etichettatura assone è stata accompagnata da etichettare dagli altri componenti del nervo dell&#39;VIII 2,3. Qui, descriviamo un metodo per l&#39;analisi anterograda dal ganglio acustico in modo selettivo labeassoni uditive l all&#39;interno del nervo VIII in via di sviluppo. In primo luogo, dopo la dissezione parziale della regione anteriore cefalica di un 8 giorni di embrione di pollo immerso nel liquido cerebrospinale artificiale ossigenato, il condotto cocleare è identificato da punti di repere anatomici. Successivamente, una micropipetta di vetro sottile tirato è posizionata per iniettare una piccola quantità di rodamina destrano ammina nella regione di canale e adiacente profonda in cui si trovano le cellule gangliari acustici. Entro trenta minuti dopo l&#39;iniezione, assoni uditive sono tracciate a livello centrale nel cervello posteriore e possono poi essere visualizzati a seguito della preparazione istologica. Questo metodo fornisce un utile strumento per gli studi di sviluppo della periferica alla formazione circuito centrale uditivo.

I componenti del nervo VIII e l&#39;anatomia del nervo stesso sono complessi e contorti (figure 1, 3). Selettivamente rintracciamento fibre derivanti da cellule gangliari acustici, segmenti del nervo VIII nonché uditive afferenti primari all&#39;interno del tronco può essere pulito tracciata e distinti dalle loro controparti vestibolari (figure 2, 3). Analogamente, questa tecnica può essere usata per studiare sporgenze periferiche delle cellule gangliari acustiche (figura 3G)...

Watch this Scientific Journal Video about Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve at JoVE.com

Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve

Qui si descrive una tecnica di microdissezione seguito da iniezione di colorante fluorescente nel ganglio acustico di embrioni di pollo primi selettiva per rintracciare uditive fibre assoni nel nervo e rombencefalo.

L&#39;analisi selettiva delle fibre uditive nel aviaria Nerve Embryonic vestibolococleare

The embryonic chick is a widely used model for the study of peripheral and central ganglion cell projections. In the auditory system, selective labeling ...

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Research

JoVE Journal

Neuroscience

9.1K Views.  University of California, Irvine. Qui si descrive una tecnica di microdissezione seguito da iniezione di colorante fluorescente nel ganglio acustico di embrioni di pollo primi selettiva per rintracciare uditive fibre assoni nel nervo e rombencefalo.

Video: Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve

Tissue Preparation and Immunostaining of Mouse Sensory Nerve Fibers Innervating Skin and Limb Bones

Detection and primary processing of physical, chemical and thermal sensory stimuli by peripheral sensory nerve fibers is key to sensory perception in animals and humans. These peripheral sensory nerve fibers express a plethora of receptors and ion channel proteins which detect and initiate specific sensory stimuli. Methods are available to characterize the electrical properties of peripheral sensory nerve fibers innervating the skin, which can also be utilized to identify the functional expression of specific ion channel proteins in these fibers. However, similar electrophysiological methods are not available (and are also difficult to develop) for the detection of the functional expression of receptors and ion channel proteins in peripheral sensory nerve fibers innervating other visceral organs, including the most challenging tissues such as bone. Moreover, such electrophysiological methods cannot be utilized to determine the expression of non-excitable proteins in peripheral sensory nerve fibers. Therefore, immunostaining of peripheral/visceral tissue samples for sensory nerve fivers provides the best possible way to determine the expression of specific proteins of interest in these nerve fibers. So far, most of the protein expression studies in sensory neurons have utilized immunostaining procedures in sensory ganglia, where the information is limited to the expression of specific proteins in the cell body of specific types or subsets of sensory neurons. Here we report detailed methods/protocols for the preparation of peripheral/visceral tissue samples for immunostaining of peripheral sensory nerve fibers. We specifically detail methods for the preparation of skin or plantar punch biopsy and bone (femur) sections from mice for immunostaining of peripheral sensory nerve fibers. These methods are not only key to the qualitative determination of protein expression in peripheral sensory neurons, but also provide a quantitative assay method for determining changes in protein expression levels in specific types or subsets of sensory fibers, as well as for determining the morphological and/or anatomical changes in the number and density of sensory fibers during various pathological states. Further, these methods are not confined to the staining of only sensory nerve fibers, but can also be used for staining any types of nerve fibers in the skin, bones and other visceral tissue.

Immunocytochemical identification of peripheral sensory nerve fiber subtypes (and detection of protein expression therein) are key to the understanding of molecular mechanisms underlying peripheral sensation. Here we describe methods for preparation of peripheral/visceral tissue samples, such as skin and limb bones, for specific immunostaining of peripheral sensory nerve fibers.

Preparazione del tessuto e immunocolorazione di fibre nervose che innervano il mouse sensoriali della pelle e ossa degli arti

Detection and primary processing of physical, chemical and thermal sensory stimuli by peripheral sensory nerve fibers is key to sensory perception in ...

Ricerca

Neuroscienze

A Lightweight, Headphones-based System for Manipulating Auditory Feedback in Songbirds

Experimental manipulations of sensory feedback during complex behavior have provided valuable insights into the computations underlying motor control and sensorimotor plasticity1. Consistent sensory perturbations result in compensatory changes in motor output, reflecting changes in feedforward motor control that reduce the experienced feedback error. By quantifying how different sensory feedback errors affect human behavior, prior studies have explored how visual signals are used to recalibrate arm movements2,3 and auditory feedback is used to modify speech production4-7. The strength of this approach rests on the ability to mimic naturalistic errors in behavior, allowing the experimenter to observe how experienced errors in production are used to recalibrate motor output.
Songbirds provide an excellent animal model for investigating the neural basis of sensorimotor control and plasticity8,9. The songbird brain provides a well-defined circuit in which the areas necessary for song learning are spatially separated from those required for song production, and neural recording and lesion studies have made significant advances in understanding how different brain areas contribute to vocal behavior9-12. However, the lack of a naturalistic error-correction paradigm - in which a known acoustic parameter is perturbed by the experimenter and then corrected by the songbird - has made it difficult to understand the computations underlying vocal learning or how different elements of the neural circuit contribute to the correction of vocal errors13.
The technique described here gives the experimenter precise control over auditory feedback errors in singing birds, allowing the introduction of arbitrary sensory errors that can be used to drive vocal learning. Online sound-processing equipment is used to introduce a known perturbation to the acoustics of song, and a miniaturized headphones apparatus is used to replace a songbird's natural auditory feedback with the perturbed signal in real time. We have used this paradigm to perturb the fundamental frequency (pitch) of auditory feedback in adult songbirds, providing the first demonstration that adult birds maintain vocal performance using error correction14. The present protocol can be used to implement a wide range of sensory feedback perturbations (including but not limited to pitch shifts) to investigate the computational and neurophysiological basis of vocal learning.

We describe the design and assembly of miniaturized headphones suitable for replacing a songbird&#x2019;s natural auditory feedback with a manipulated acoustic signal. Online sound processing hardware is used to manipulate song output, introduce real-time errors in auditory feedback via the headphones, and drive vocal motor learning.

Un leggero, Cuffie-based per la gestione di sistema feedback uditivo in Songbirds

Experimental manipulations of sensory feedback during complex behavior have provided valuable insights into the computations underlying motor control and ...

Optogenetic Stimulation of the Auditory Nerve

Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted deaf subjects1-6. Nonetheless, sound coding with current CIs has poor frequency and intensity resolution due to broad current spread from each electrode contact activating a large number of SGNs along the tonotopic axis of the cochlea7-9. Optical stimulation is proposed as an alternative to electrical stimulation that promises spatially more confined activation of SGNs and, hence, higher frequency resolution of coding. In recent years, direct infrared illumination of&#160;the cochlea has been used to evoke responses in the auditory nerve10. Nevertheless it requires higher energies than electrical stimulation10,11 and uncertainty remains as to the underlying mechanism12. Here we describe a method based on optogenetics to stimulate SGNs with low intensity blue light, using transgenic mice with neuronal expression of channelrhodopsin 2 (ChR2)13 or virus-mediated expression of the ChR2-variant CatCh14. We used micro-light emitting diodes (&#181;LEDs) and fiber-coupled lasers to stimulate ChR2-expressing SGNs through a small artificial opening (cochleostomy) or the round window. We assayed the responses by scalp recordings of light-evoked potentials (optogenetic auditory brainstem response: oABR) or by microelectrode recordings from the auditory pathway and compared them with acoustic and electrical stimulation.

Cochlear implants (CIs) enable hearing by direct electrical stimulation of the auditory nerve. However, poor frequency and intensity resolution limits the quality of hearing with CIs. Here we describe optogenetic stimulation of the auditory nerve in mice as an alternative strategy for auditory research and developing future CIs.

Stimolazione optogenetic del nervo uditivo

Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted ...

Conditional Genetic Transsynaptic Tracing in the Embryonic Mouse Brain

Anatomical path tracing is of pivotal importance to decipher the relationship between brain and behavior. Unraveling the formation of neural circuits during embryonic maturation of the brain however is technically challenging because most transsynaptic tracing methods developed to date depend on stereotaxic tracer injection. To overcome this problem, we developed a binary genetic strategy for conditional genetic transsynaptic tracing in the mouse brain. Towards this end we generated two complementary knock-in mouse strains to selectively express the bidirectional transsynaptic tracer barley lectin (BL) and the retrograde transsynaptic tracer Tetanus Toxin fragment C from the ROSA26 locus after Cre-mediated recombination. Cell-specific tracer production in these mice is genetically encoded and does not depend on mechanical tracer injection. Therefore our experimental approach is suitable to study neural circuit formation in the embryonic murine brain. Furthermore, because tracer transfer across synapses depends on synaptic activity, these mouse strains can be used to analyze the communication between genetically defined neuronal populations during brain development at a single cell resolution. Here we provide a detailed protocol for transsynaptic tracing in mouse embryos using the novel recombinant ROSA26 alleles. We have utilized this experimental technique in order to delineate the neural circuitry underlying maturation of the reproductive axis in the developing female mouse brain.

Capitalizing on a binary genetic strategy we provide a detailed protocol for neural circuit tracing in mice that express complementary transsynaptic tracers after Cre-mediated recombination. Because cell-specific tracer production is genetically encoded, our experimental approach is suitable to study the formation and maturation of neural circuitry during murine embryonic brain development at a single cell resolution.

Condizionale genetica Transsynaptic Tracing nel cervello embrionali di topo

Anatomical path tracing is of pivotal importance to decipher the relationship between brain and behavior. Unraveling the formation of neural circuits ...

Laser-guided Neuronal Tracing In Brain Explants

We present a technique which combines an in vitro tracer injection protocol, which uses a series of electrical and pressure pulses to increase dye uptake through electroporation in brain explants with targeted laser illumination and matching filter goggles during the procedure. The described technique of in vitro electroporation by itself yields relatively good visual control for targetting certain areas of the brain. By combining it with laser excitation of fluorescent genetic markers and their read-out through band-passing filter goggles, which can pick up the emissions of the genetically labeled cells/nuclei and the fluorescent tracing dye, a researcher can substantially increase the accuracy of injections by finding the area of interest and controlling for the dye-spread/uptake in the injection area much more efficiently. In addition, the laser illumination technique allows to study the functionality of a given neurocircuit by providing information about the type of neurons projecting to a certain area in cases where the GFP expression is linked to the type of transmitter expressed by a subpopulation of neurons.

We describe a technique to label neurons and their processes via anterograde or retrograde tracer injections into brain nuclei using an in vitro preparation. We modified an existing method of in vitro tracer electroporation by taking advantage of fluorescently labeled mouse mutants and basic optical equipment in order to increase labeling accuracy.

Neuronal Tracing negli espianti cerebrali a guida laser

We present a technique which combines an in vitro tracer injection protocol, which uses a series of electrical and pressure pulses to increase dye uptake ...

Three-dimensional Imaging and Analysis of Mitochondria within Human Intraepidermal Nerve Fibers

The goal of this protocol is to study mitochondria within intraepidermal nerve fibers. Therefore, 3D imaging and analysis techniques were developed to isolate nerve-specific mitochondria and evaluate disease-induced alterations of mitochondria in the distal tip of sensory nerves. The protocol combines fluorescence immunohistochemistry, confocal microscopy and 3D image analysis techniques to visualize and quantify nerve-specific mitochondria. Detailed parameters are defined throughout the procedures in order to provide a concrete example of how to use these techniques to isolate nerve-specific mitochondria. Antibodies were used to label nerve and mitochondrial signals within tissue sections of skin punch biopsies, which was followed by indirect immunofluorescence to visualize nerves and mitochondria with a green and red fluorescent signal respectively. Z-series images were acquired with confocal microscopy and 3D analysis software was used to process and analyze the signals. It is not necessary to follow the exact parameters described within, but it is important to be consistent with the ones chosen throughout the staining, acquisition and analysis steps. The strength of this protocol is that it is applicable to a wide variety of circumstances where one fluorescent signal is used to isolate other signals that would otherwise be impossible to study alone.

This protocol uses three-dimensional (3D) imaging and analysis techniques to visualize and quantify nerve-specific mitochondria. The techniques are applicable to other situations where one fluorescent signal is used to isolate a subset of data from another fluorescent signal.

Imaging tridimensionale e l'analisi dei mitocondri all'interno di fibre nervose umane Intraepidermal

The goal of this protocol is to study mitochondria within intraepidermal nerve fibers. Therefore, 3D imaging and analysis techniques were developed to ...

Imaging Serotonergic Fibers in the Mouse Spinal Cord Using the CLARITY/CUBIC Technique

Long descending fibers to the spinal cord are essential for locomotion, pain perception, and other behaviors. The fiber termination pattern in the spinal cord of the majority of these fiber systems have not been thoroughly investigated in any species. Serotonergic fibers, which project to the spinal cord, have been studied in rats and opossums on histological sections and their functional significance has been deduced based on their fiber termination pattern in the spinal cord. With the development of CLARITY and CUBIC techniques, it is possible to investigate this fiber system and its distribution in the spinal cord, which is likely to reveal previously unknown features of serotonergic supraspinal pathways. Here, we provide a detailed protocol for imaging the serotonergic fibers in the mouse spinal cord using the combined CLARITY and CUBIC techniques. The method involves perfusion of a mouse with a hydrogel solution and clarification of the tissue with a combination of clearing reagents. Spinal cord tissue was cleared in just under two weeks, and the subsequent immunofluorescent staining against serotonin was completed in less than ten days. With a multi-photon fluorescent microscope, the tissue was scanned and a 3D image was reconstructed using Osirix software.

Supraspinal projections are important for pain perception and other behaviors, and serotonergic fibers are one of these fiber systems. The present study focused on the application of the combined CLARITY/CUBIC protocol to the mouse spinal cord in order to investigate the termination of these serotonergic fibers.

Imaging Fibre serotoninergici nel midollo spinale mouse Uso del CHIAREZZA / Tecnica CUBIC

Long descending fibers to the spinal cord are essential for locomotion, pain perception, and other behaviors. The fiber termination pattern in the spinal ...

In Vitro Characterization of the Electrophysiological Properties of Colonic Afferent Fibers in Rats

Dysfunction of the colonic sensory nerves has been implicated in the pathophysiology of several common conditions, including functional and inflammatory bowel diseases and diabetes. Here, we describe a protocol for the in vitro characterization of the electrophysiological properties of colonic afferents in rats. The colorectum, with the intact pelvic ganglion (PG) attached, is removed from the rat; superfused with carbogenated Krebs solution in the recording chamber; and cannulated at the oral and anal ends to allow for distension. A fine nerve bundle emanating from the PG is identified, and the multiunit afferent nerve activity is recorded using a suction electrode. Distension of the colonic segment elicits gradual increases in multiunit discharge. A principal component analysis is conducted to differentiate the low-threshold, the high-threshold, and the wide-dynamic range afferent fibers. Chemical sensitivity of colonic afferents can be studied through the bath or intraluminal administration of test compounds. This protocol can be modified for application to other species, such as mice and guinea pigs, and to study the differences in the electrophysiological properties of thoracolumbar/hypogastric and lumbosacral/pelvic afferents of the descending colon in normal and pathological conditions.

In Vitro Characterization of the Electrophysiological Properties of Colonic Afferent Fibers in Rats

Abnormal sensory function underlies visceral pain and other symptoms of functional and inflammatory bowel diseases. A protocol for the electrophysiological recording of the colonic afferent nerves in an ex vivo rat colorectum preparation is presented here.

In Vitro Caratterizzazione delle proprietà elettrofisiologiche di fibre afferenti coliche in ratti

Dysfunction of the colonic sensory nerves has been implicated in the pathophysiology of several common conditions, including functional and inflammatory ...

Retrograde Neuroanatomical Tracing of Phrenic Motor Neurons in Mice

Phrenic motor neurons are cervical motor neurons originating from C3 to C6 levels in most mammalian species. Axonal projections converge into phrenic nerves innervating the respiratory diaphragm. In spinal cord slices, phrenic motor neurons cannot be identified from other motor neurons on morphological or biochemical criteria. We provide the description of procedures for visualizing phrenic motor neuron cell bodies in mice, following intrapleural injections of cholera toxin subunit beta (CTB) conjugated to a fluorophore. This fluorescent neuroanatomical tracer has the ability to be caught up at the diaphragm neuromuscular junction, be carried retrogradely along the phrenic axons and reach the phrenic cell bodies. Two methodological approaches of intrapleural CTB delivery are compared: transdiaphragmatic versus transthoracic injections. Both approaches are successful and result in similar number of CTB-labeled phrenic motor neurons. In conclusion, these techniques can be applied to visualize or quantify the phrenic motor neurons in various experimental studies such as those focused on the diaphragm-phrenic circuitry.

Here, we describe a protocol for identifying phrenic motor neurons in mice after intrapleural delivery of fluorophore conjugated cholera toxin subunit beta. Two techniques are compared to inject the pleural cavity: transdiaphragmatic versus transthoracic approaches.

Analisi Neuroanatomical retrogrado dei motoneuroni frenico in topi

Phrenic motor neurons are cervical motor neurons originating from C3 to C6 levels in most mammalian species. Axonal projections converge into phrenic ...

Targeting Alpha Synuclein Aggregates in Cutaneous Peripheral Nerve Fibers by Free-floating Immunofluorescence Assay

To date, for most neurodegenerative diseases only a post-mortem histopathological definitive diagnosis is available. For Parkinson&#39;s disease (PD), the diagnosis still relies only on clinical signs of motor involvement that appear later on in the disease course, when most of the dopaminergic neurons are already lost. Hence, there is a strong need for a biomarker that can identify patients at the beginning of disease or at the risk of developing it. Over the last few years, skin biopsy has proved to be an excellent research and diagnostic tool for peripheral nerve diseases such as small fiber neuropathy. Interestingly, a small fiber neuropathy and alpha synuclein (&#945;Syn) neural deposits have been shown by skin biopsy in PD patients. Indeed, skin biopsy has the great advantage of being an easily accessible, minimally invasive and painless procedure that allows the analysis of peripheral nervous tissue prone to the pathology. Moreover, the possibility of repeating the skin biopsy in the course of the follow-up of the same patient allows studying the longitudinal correlation with the disease progression. We set up a standardized reliable protocol to investigate the presence of &#945;Syn aggregates in skin nerve fibers of the PD patient. This protocol involves few short fixation steps, a cryotome sectioning and then a free-floating immunofluorescence double-staining with two specific antibodies: anti Protein Gene Product 9.5 (PGP9.5) to mark the cutaneous nerve fibers and anti 5G4 for detecting &#945;Syn aggregates. It is a versatile, sensitive and easy to perform protocol that can also be applied for targeting other proteins of interest in skin nerves. The ability to mark &#945;Syn aggregates is another step forward to the use of skin biopsy as a tool for establishing a pre-mortem histopathological diagnosis of PD.

Here, we present a protocol for a free-floating indirect immunofluorescence assay on skin biopsy sections that allows for the identification of disease specific conformation variants of alpha synuclein involved in Parkinson disease and multiple proteins of the peripheral nervous system.

Targeting Alpha Synuclein Aggregati in cutaneous periferici nervose fibre nervose da Pro(Enunciante autofluorescenza libera)

To date, for most neurodegenerative diseases only a post-mortem histopathological definitive diagnosis is available. For Parkinson&#39;s disease (PD), the ...