Diese Arbeit wurde von der UC Discovery-Proof of Concept Zuschuss und durch die NIH (R00 EB007241) unterstützt. Die Autoren möchte auch Jacqueline Hubbard für ihre Unterstützung danken, die in diesem Experiment.

Ein. Chirurgische Vorbereitung <ol><li> Weibliche CD 1 Mäuse im Alter zwischen 6-8 Wochen wurden in unseren Experimenten verwendet. </li><li> Anästhesieren die Maus mit einer intraperitonealen Injektion von Ketamin und Xylazin einer Kombination (80 mg / kg ketamine/10 mg / kg Xylazin). Platzieren Sie die Maus auf einer homöothermen pad die optimale Körpertemperatur bei ~ 37 ° C zu gewährleisten Kontinuierliche Überwachung von Betäubungsmitteln durch Testen Tieres Reflexe (z. B. Einklemmen Fuß mit stumpfen Pinzette) und injizieren mehr Betäubung, wenn nötig. </li><li> Schmieren Sie beide Augen mit einem künstlichen Riss Salbe. Entfernen Sie Haare auf der Kopfhaut mit einer Rasierklinge und entfernen restliche Haar mit 70% Alkohol prep Pads. Tragen Sie eine dünne Schicht von Nair Enthaarungscreme auf der Kopfhaut und warten Sie 2 min für sie wirksam wird. Vorsichtig abwischen Nair und die restlichen Haare mit Kochsalzlösung angefeuchteten Wattestäbchen und Alkohol prep Pads. Scalp sollte nun komplett haarlos. </li><li> Desinfizieren der Kopfhaut mit einem betadine Tupfer-Stick und reinigen mit 70% Ethanol prep Pads. </li><li> Vorsichtig wickeln Sie das Tier in Operationstüchern die optimale Körpertemperatur von ca. 37 ° C sicherzustellen und montieren das Tier auf einem stereotaktischen Rahmen, um den Schädel zu immobilisieren. Tippen Sie auf den Schädel seiner Stabilität zu gewährleisten. Eine Liste der verwendeten Materialien sind in Tabelle 1 bereitgestellt. </li></ol> 2. Verdünnt-skull Kortikale Fenster Vorbereitung <ol><li> Starten Sie den Einschnitt an der Mittellinie zwischen den Augen. Weiterhin kaudal zur Mittellinie zwischen den Ohren. Teil der Haut mit einer Pinzette. </li><li> Suchen Sie den Bereich unter einem Binokular verdünnt und entfernen Sie vorsichtig die Blende mit einer Pinzette. Trocknen Sie die Schädel mit sterilen Wattestäbchen, bevor Sie die ausgedünnt kortikale Fenster. In unseren Experimenten haben wir eine 4 × 4 mm ausgedünnt kranialen Fensters ~ 1 mm posterior und lateral bregma. </li><li> Beginnen Ausdünnung den Schädel mit einem runden Hartmetallfräser mit Bohrer 0,75 mm in einem chirurgischen Bohrmaschine mit Licht Kehrbewegung only. Wenden Sie keine direkten Druck auf den Schädel. Stoppen Bohren alle 20-30 Sek. Knochen Staub mit steriler Kochsalzlösung und Wattestäbchen zu entfernen und zu vermeiden Überhitzung des Schädels. Die Kochsalzlösung wird auch in Ableitung der Wärme über den Schädel zu unterstützen. </li><li> Sobald die äußere Schicht des kompakten Knochen vollständig entfernt wird die mittlere Schicht Spongiosa sollte jetzt sichtbar. Es könnten leichten Blutungen wie Blutgefäße sind deutlicher in der Spongiosa Schicht. Wechseln Sie zu einem grünen Stein bur und weiter bohren mit besonderer Vorsicht die schwammigen Schicht ist feiner. Der grüne Stein bur löscht weniger Knochen während der Erstellung Ebenheit der gesamten kranialen Fenster. Stoppen Bohren gelegentlich Knochenmehl zu entfernen und den Schädel zu kühlen. </li><li> Schließlich ist, wenn der Schädel ist transparenter geworden und Gefäßen am Gehirn jetzt sichtbar, beginnen Polieren des Schädels mit einem Polier-bur. Dies ermöglicht eine genauere Ausdünnung während Glätten den Schädel. Überprüfen Dünne des skull durch leichtes Antippen mit einer Pinzette. Stoppen Polierens, wenn der Schädel wird etwas flexibel. </li><li> Der verdünnte kranialen Fenster sollte nun völlig glatt und reflektierend und bereit zum Abbilden (Abbildung 1). Aufgrund der Art der hoch streuenden Gewebe des Gehirns sollte der Schädel auf mindestens 55 um für die optimale Eindringtiefe verdünnbar. Eine Liste der verwendeten Materialien sind in Tabelle 1 bereitgestellt. </li></ol> 3. Optical Coherence Tomography Imaging <ol><li> Nach der Operation abgeschlossen ist, überprüfen Tieres Atemfrequenz und Reflexe auf ein angemessenes Niveau der Anästhesie sicherzustellen und zu verwalten zusätzliche Betäubung, wenn nötig. Entfernen Tier aus der stereotaktischen Rahmen halten Tier-OP-Abdeckungen gewickelt und Transport Tier zum Imaging-Station. </li><li> Vor Bildgebung überprüfen Zeichen für Reflexe und gelten zusätzliche künstliche Tränenflüssigkeit, wenn nötig. Montieren Tier auf den stereotaktischen Rahmen, um den Schädel zu sichern. </li><li> Platz Tier unterOktober Kamera und positionieren Sie den TSCW unter dem optischen Strahl (Abbildung 2). Eine Querschnittsansicht des Schädels und Gehirn kann nun visualisiert werden (Abbildung 3). </li><li> Die Datenerfassung kann beginnen, sobald Bereich des Interesses befindet. Zum Abbilden Zwecke, verwenden wir Galvo Spiegeln, eine Abbildungsanordnung Fenster mit einer Breite von 4,0 mm zu erreichen. Ein bildgebendes Tiefe von 2 mm wurde mit 6 mW des einfallenden Leistung und einem Brennpunkt 1 mm unterhalb des ausgedünnten Schädels erhalten. Jeder Querschnittsfläche bestand aus 2.048 axiale Scans mit einer Erfassungsrate von 0,14 Sekunden pro Bild. </li><li> Volumetrischen Abtastungen des Gehirns kann auch durch Sammeln einer Serie von 2D-Querschnittbild-Bilder unter Verwendung von zwei Sätzen von Galvo Spiegel für xy Abtasten mit dem ersten Spiegel Galvo Abtasten des Strahls in der sagittalen Richtung und der zweiten Spiegel Galvo Abtasten in der koronalen erhalten werden Richtung. </li></ol>

<ol>
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M., Kadono, H., Tanifuji, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Swept+source+optical+coherence+tomography+as+a+tool+for+real+time+visualization+and+localization+of+electrodes+used+in+electrophysiological+studies+of+brain+in+vivo.">Swept source optical coherence tomography as a tool for real time visualization and localization of electrodes used in electrophysiological studies of brain in vivo.</a> Biomedical Optics Express. 2, 3129-3134 (2011).</li><li>Huang, D., Swanson, E. A., Lin, C. P., Schuman, J. S., Stinson, W. G., Chang, W., Hee, M. R., Flottee, T., Gregory, K., Puliafito, C. A., Fujimoto, J. 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M., Calabresi, P. A., Saidha, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+assessment+of+retinal+neuronal+layers+in+multiple+sclerosis+with+maual+and+automated+optical+coherence+tomography+segementation+techniques.">In vivo assessment of retinal neuronal layers in multiple sclerosis with maual and automated optical coherence tomography segementation techniques.</a> J. Neurol. , (2012).</li><li>Frohman, E. M., Fujimoto, J. G., Frohman, T. C., Calabresi, P. A., Cutter, G., Balcer, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+coherence+tomography:+a+window+into+the+mechanisms+of+multiple+sclerosis.">Optical coherence tomography: a window into the mechanisms of multiple sclerosis.</a> Nature Clinical Practice. 4, 664-675 (2008).</li><li>Gill, A. S., Rajneesh, K. F., Owen, C. 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Keine Interessenskonflikte erklärt.

Imaging mit OCT und einem ausgedünnten Schädel ist eine neuartige bildgebende Technik, die erst seit kurzem 15, 16 untersucht. In unseren Experimenten haben wir gezeigt, die Machbarkeit der SD-OCT-Bildgebung durch eine TSCW in einem Mausmodell in vivo. Aus unseren Ergebnissen wird der Schädel auf ca. 55 um verdünnt und die Eindringtiefe wird bei etwa 1 mm mit Bildauflösung von 8 um und 20 um in der axialen und lateralen Richtung erhalten wurden. In dem Signal-Intensitätsprofil, erhöht OCT-Bild...

Seit seiner Einführung in den frühen 1990er Jahren Oktober wurde ausgiebig für biologische Bildgebung von Gewebe Struktur und Funktion 2 verwendet. Oktober erzeugt Querschnittsbilder durch Messen Echo Zeitverzögerung des rückgestreuten Lichts 4 durch Umsetzung mit geringer Kohärenz Lichtquelle mit einem faseroptischen Michelson Interferometer 2,4. SD-OCT, auch als Fourier Domain OCT (FD-OCT) bekannt ist, wurde zum ersten Mal in 1995 5 eingeführt und bietet eine überlegene Bildgebungsmodalität im Vergleich zu herkömmlichen Zeitbereich Oktober (TD-OCT). Im SD-OCT wird der Referenzarm stationär gehalten, was zu einer hohen Geschwindigkeit und ultrahoher Auflösung Bildaufnahme 6-9. Derzeit haben TSCW Modelle weitgehend in vivo Bildgebung des Gehirns Anwendungen der Zwei-Photonen-Mikroskopie an Stelle eines traditionellen Kraniotomie verwendet. Diese TSCW wurden gleichzeitig mit einer benutzerdefinierten Schädel Platte oder einem Deckglas 10-13 verwendet, um zusätzliche ima bietenGing Stabilität. In unseren Studien haben wir festgestellt, dass Zubehör wie diese sind nicht für die OCT-Bildgebung erforderlich, wenn ein TSCW verwendet wird. Daher ermöglicht das Fehlen eines Schädels Platte oder Glasdeckgläschen für ein breiteres Spektrum von bildgebenden Fenstergröße, wie sie mit dem optischen Strahl interferieren können und verändern OCT-Bilder. Eine ausgedünnte Schädel Vorbereitung hat sich als in der Bildgebung des Gehirns mit Zwei-Photonen-Mikroskopie 10-13 vorteilhaft. In unseren Experimenten verwenden wir eine SD-OCT-Systems zur Abbildung der Hirnrinde in vivo durch einen TSCW. Unsere eigene SD-OCT-Bildgebung Setup enthält einen breitbandigen, geringer Kohärenz Lichtquelle aus zwei Superlumineszenzdioden (SLD) in 1295 nm mit einer Bandbreite von 97 nm, was zu einer axialen und lateralen Auflösung von 8 um und 20 um zentriert bzw. 14 . Mit unserem optischen Bildgebung Gerät, stellen wir uns, dass die Bildgebung durch eine TSCW großes Potenzial bei der Identifizierung und Visualisierung von Strukturen und Funktionen in der optically dichten Hirngewebe.

<table border="1"><tbody><tr><td> Materialien </td><td> Firma </td><td> Katalog-Nummer </td><td> Kommentare </td></tr><tr><td> Ketamin </td><td> Phoenix Pharmaceuticals </td><td> 57319-542-02 </td><td></td></tr><tr><td> Xylazin </td><td> Akorn, Inc. </td><td> 139-236 </td><td></td></tr><tr><td> Künstliche Tränen Salbe </td><td> Rugby </td><td> 0536-6550-91 </td><td></td></tr><tr><td> Nair </td><td> Church &amp; Dwight Co., Inc. </td><td> 4010130 </td><td></td></tr><tr><td> Sterile Alkohol Prep Pad </td><td> Kendall Healthcare </td><td> 6818 </td><td></td></tr><tr><td> Wattestäbchen Applikatoren </td><td> Fisherbrand </td><td> 23-400-115 </td><td></td></tr><tr><td> Betadine Lösung Swabstick </td><td> Purdue Produkte &lt;/ Td&gt; <td> 67618-153-01 </td><td></td></tr><tr><td> Saline Solution, 0,9% </td><td> Phoenix Pharmaceuticals </td><td> 57319-555-08 </td><td></td></tr><tr><td> Stereotaktischen Rahmen </td><td> Stoelting </td><td></td><td></td></tr><tr><td> High Speed ​​Surgical Handbohrmaschine </td><td> Foredom </td><td></td><td> 38.000 rpm </td></tr><tr><td> Carbide Rosenbohrer </td><td> Stoelting </td><td></td><td> 0,75 mm </td></tr><tr><td> Dura-Green Stones </td><td> Shofu </td><td></td><td> Shank: HP Form: BA1 </td></tr><tr><td> CompoMaster Coarse &amp; CompoMaster Polisher </td><td> Shofu </td><td></td><td> Form: Mini-Pt. </td></tr><tr><td> SpaceDrapes </td><td> Braintree Scientific, Inc. </td><td></td><td></td></tr></tbody></table>

thinned-skull cortical window technique for in vivo optical coherence tomography imaging

Optische Kohärenztomographie (OCT) ist eine biomedizinische Bildgebung mit hoher räumlicher und zeitlichen Auflösung. Mit seiner minimal-invasive Ansatz Oktober wurde ausgiebig in der Augenheilkunde, Dermatologie und Gastroenterologie 1-3 verwendet. Mit einem ausgedünnten Schädel kortikale Fenster (TSCW) beschäftigen wir Spektral-Domain-OCT (SD-OCT) Modalität als ein Werkzeug zur Abbildung der Hirnrinde in vivo. Üblicherweise ein geöffneter-Schädel für bildgebende wurde verwendet, da es mehr Flexibilität bietet, jedoch eine weniger invasive TSCW Ansatz und ist ein wirksames Mittel für die langfristige Bildgebung in Neuropathologie Studien. Hier präsentieren wir eine Methode zum Erstellen einer TSCW in einem Mausmodell in vivo OCT-Bildgebung der Großhirnrinde.

Nach dem Erstellen eines ausgedünnten Fenster über der Großhirnrinde das Gefäßsystem sollte nun optisch prominente (Abbildung 1) und wird für einen tieferen Bildtiefe ermöglichen (bis zu 1 mm). Die rechten Cortex wird auf ungefähr 55 um ausgedünnt zu einer normalen Schädels an 140 um (Abbildung 1) gemessen und stellt eine größere optische Klarheit verglichen. Weitere Verdünnung auf 10-15 &amp;mgr; m ist möglich 11 jedoch nicht notwendig, da die Verwendung von Gl...

Watch this Scientific Journal Video about Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging at JoVE.com

Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging

Wir stellen eine Methode zur Schaffung eines ausgedünnten Schädel kortikale Fenster (TSCW) in einem Mausmodell für<em&gt; In vivo</em&gt; OCT-Bildgebung der Großhirnrinde.

Verdünnt-skull Kortikale Fenster-Technik für<em&gt; In Vivo</em&gt; Optical Coherence Tomography Imaging

Optical coherence tomography (OCT) is a biomedical imaging technique  with high spatial-temporal resolution. With its minimally invasive approach OCT  has ...

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Neuroscience

Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging

15.1K Aufrufe.  University of California, Riverside. Wir stellen eine Methode zur Schaffung eines ausgedünnten Schädel kortikale Fenster (TSCW) in einem Mausmodell für In vivo OCT-Bildgebung der Großhirnrinde.

Serie: Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging

A Thin-skull Window Technique for Chronic Two-photon In vivo Imaging of Murine Microglia in Models of Neuroinflammation

Traditionally in neuroscience, in vivo two photon imaging of the murine central nervous system has either involved the use of open-skull1,2 or thinned-skull 3 preparations. While the open-skull technique is very versatile, it is not optimal for studying microglia because it is invasive and can cause microglial activation. Even though the thinned-skull approach is minimally invasive, the repeated re-thinning of skull required for chronic imaging increases the risks of tissue injury and microglial activation and allows for a limited number of imaging sessions. Here we present a chronic thin-skull window method for monitoring murine microglia in vivo over an extended period of time using two-photon microscopy. We demonstrate how to prepare a stable, accessible, thinned-skull cortical window (TSCW) with an apposed glass coverslip that remains translucent over the course of three weeks of intermittent observation. This TSCW preparation is far more immunologically inert with respect to microglial activation than open craniotomy or repeated skull thinning and allows an arbitrary number of imaging sessions during a time period of weeks. We prepare TSCW in CX3CR1 GFP/+ mice 4 to visualize microglia with enhanced green fluorescent protein to &le;150 &mu;m beneath the pial surface. We also show that this preparation can be used in conjunction with stereotactic brain injections of the HIV-1 neurotoxic protein Tat, adjacent to the TSCW, which is capable of inducing durable microgliosis. Therefore, this method is extremely useful for examining changes in microglial morphology and motility over time in the living brain in models of HIV Associated Neurocognitive Disorder (HAND) and other neurodegenerative diseases with a neuroinflammatory component.

A Thin-skull Window Technique for Chronic Two-photon In vivo Imaging of Murine Microglia in Models of Neuroinflammation

We describe a method for repeatedly visualizing murine microglia and circulating monocytes in vivo over hours, days or weeks using transcranial two-photon microscopy. We demonstrate how to prepare a thinned-skull window that allows intermittent observation of quiescent microglia that can be activated by adjacent stereotactic injection of the HIV-1 regulatory protein Tat.

Ein Thin-Schädel Fenster-Technik für chronische Zwei-Photonen- In-vivo- Imaging von Murine Mikrogliazellen in Modelle der Neuroinflammation

Traditionally in neuroscience, in vivo two photon imaging of the murine central nervous system has either involved the use of open-skull1,2 or ...

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Neurowissenschaften

Chronic Imaging of Mouse Visual Cortex Using a Thinned-skull Preparation

In vivo imaging using two-photon laser scanning microscopy (2PLSM) allows the study of living cells and neuronal processes in the intact brain. The technique presented here allows the imaging of the same area of the brain at several time points (chronic imaging) with microscopic resolution allowing the tracking of dendritic spines which are the small structures that represent the majority of postsynaptic excitatory sites in the CNS. The ability to clearly resolve fine cortical structures over several time points has many advantages, specifically in the study of brain plasticity in which morphological changes at synapses and circuit remodeling may help explain underlying mechanisms. In this video and supplementary material, we show a protocol for chronic in vivo imaging of the intact brain using a thinned-skull preparation. The thinned-skull preparation is a minimally invasive approach, which avoids potential damage to the dura and/or cortex, thus reducing the onset of an inflammatory response. When this protocol is performed correctly, it is possible to clearly monitor changes in dendritic spine characteristics in the intact brain over a prolonged period of time.

In this video and supplemental material, we show a protocol for chronic in vivo imaging of the intact brain using a thinned-skull preparation.

Chronische Imaging of Mouse Visual Cortex Mit einem ausgedünnten Schädel Vorbereitung

In vivo imaging using two-photon laser scanning microscopy (2PLSM) allows the study of living cells and neuronal processes in the intact brain. The ...

A Polished and Reinforced Thinned-skull Window for Long-term Imaging of the Mouse Brain

In vivo imaging of cortical function requires optical access to the brain without disruption of the intracranial environment. We present a method to form a polished and reinforced thinned skull (PoRTS) window in the mouse skull that spans several millimeters in diameter and is stable for months. The skull is thinned to 10 to 15 &mu;m in thickness with a hand held drill to achieve optical clarity, and is then overlaid with cyanoacrylate glue and a cover glass to: 1) provide rigidity, 2) inhibit bone regrowth and 3) reduce light scattering from irregularities on the bone surface. Since the skull is not breached, any inflammation that could affect the process being studied is greatly reduced. Imaging depths of up to 250 &mu;m below the cortical surface can be achieved using two-photon laser scanning microscopy. This window is well suited to study cerebral blood flow and cellular function in both anesthetized and awake preparations. It further offers the opportunity to manipulate cell activity using optogenetics or to disrupt blood flow in targeted vessels by irradiation of circulating photosensitizers.

We present a method to form an imaging window in the mouse skull that spans millimeters and is stable for months without inflammation of the brain. This method is well suited for longitudinal studies of blood flow, cellular dynamics, and cell/vascular structure using two-photon microscopy.

Eine polierte und verstärkte ausgedünnten Schädel Fenster für Langzeit-Imaging im Gehirn der Maus

In vivo imaging of cortical function requires optical access to the brain without disruption of the intracranial environment. We present a method to form ...

In Vivo Two-photon Imaging Of Experience-dependent Molecular Changes In Cortical Neurons

The brain's ability to change in response to experience is essential for healthy brain function, and abnormalities in this process contribute to a variety of brain disorders1,2. To better understand the mechanisms by which brain circuits react to an animal's experience requires the ability to monitor the experience-dependent molecular changes in a given set of neurons, over a prolonged period of time, in the live animal. While experience and associated neural activity is known to trigger gene expression changes in neurons1,2, most of the methods to detect such changes do not allow repeated observation of the same neurons over multiple days or do not have sufficient resolution to observe individual neurons3,4. Here, we describe a method that combines in vivo two-photon microscopy with a genetically encoded fluorescent reporter to track experience-dependent gene expression changes in individual cortical neurons over the course of day-to-day experience. 
One of the well-established experience-dependent genes is Activity-regulated cytoskeletal associated protein (Arc)5,6. The transcription of Arc is rapidly and highly induced by intensified neuronal activity3, and its protein product regulates the endocytosis of glutamate receptors and long-term synaptic plasticity7. The expression of Arc has been widely used as a molecular marker to map neuronal circuits involved in specific behaviors3. In most of those studies, Arc expression was detected by in situ hybridization or immunohistochemistry in fixed brain sections. Although those methods revealed that the expression of Arc was localized to a subset of excitatory neurons after behavioral experience, how the cellular patterns of Arc expression might change with multiple episodes of repeated or distinctive experiences over days was not investigated. 
In vivo two-photon microscopy offers a powerful way to examine experience-dependent cellular changes in the living brain8,9. To enable the examination of Arc expression in live neurons by two-photon microscopy, we previously generated a knock-in mouse line in which a GFP reporter is placed under the control of the endogenous Arc promoter10. This protocol describes the surgical preparations and imaging procedures for tracking experience-dependent Arc-GFP expression patterns in neuronal ensembles in the live animal. In this method, chronic cranial windows were first implanted in Arc-GFP mice over the cortical regions of interest. Those animals were then repeatedly imaged by two-photon microscopy after desired behavioral paradigms over the course of several days. This method may be generally applicable to animals carrying other fluorescent reporters of experience-dependent molecular changes4.

In Vivo Two-photon Imaging Of Experience-dependent Molecular Changes In Cortical Neurons

Experience-dependent molecular changes in neurons are essential for the brain's ability to adapt in response to behavioral challenges. An in vivo two-photon imaging method is described here that allows the tracking of such molecular changes in individual cortical neurons through genetically encoded reporters.

In Vivo Zwei-Photonen-Imaging Of Experience-abhängigen molekularen Veränderungen in kortikalen Neuronen

The brain's ability to change in response to experience is essential for healthy brain function, and abnormalities in this process contribute to a variety ...

Two-Photon in vivo Imaging of Dendritic Spines in the Mouse Cortex Using a Thinned-skull Preparation

In the mammalian cortex, neurons form extremely complicated networks and exchange information at synapses. Changes in synaptic strength, as well as addition/removal of synapses, occur in an experience-dependent manner, providing the structural foundation of neuronal plasticity. As postsynaptic components of the most excitatory synapses in the cortex, dendritic spines are considered to be a good proxy of synapses. Taking advantages of mouse genetics and fluorescent labeling techniques, individual neurons and their synaptic structures can be labeled in the intact brain. Here we introduce a transcranial imaging protocol using two-photon laser scanning microscopy to follow fluorescently labeled postsynaptic dendritic spines over time in vivo. This protocol utilizes a thinned-skull preparation, which keeps the skull intact and avoids inflammatory effects caused by exposure of the meninges and the cortex. Therefore, images can be acquired immediately after surgery is performed. The experimental procedure can be performed repetitively over various time intervals ranging from hours to years. The application of this preparation can also be expanded to investigate different cortical regions and layers, as well as other cell types, under physiological and pathological conditions.

Two-Photon in vivo Imaging of Dendritic Spines in the Mouse Cortex Using a Thinned-skull Preparation

Time-lapse imaging in the living animal provides valuable information on structural reorganization in the intact brain. Here, we introduce a thinned-skull preparation that allows transcranial imaging of fluorescently labeled synaptic structures in the living mouse cortex by two-photon microscopy.

Zwei-Photonen-<em&gt; In vivo</em&gt; Imaging von dendritischen Dornen in der Maus Cortex Mit einem ausgedünnten Schädel Vorbereitung

In the mammalian cortex, neurons form extremely complicated networks and exchange information at synapses. Changes in synaptic strength, as well as ...

Optical Coherence Tomography: Imaging Mouse Retinal Ganglion Cells In Vivo

Structural changes in the retina are common manifestations of ophthalmic diseases. Optical coherence tomography (OCT) enables their identification in vivo&#8212;rapidly, repetitively, and at a high resolution. This protocol describes OCT imaging in the mouse retina as a powerful tool to study optic neuropathies (OPN). The OCT system is an interferometry-based, non-invasive alternative to common post mortem histological assays. It provides a fast and accurate assessment of retinal thickness, allowing the possibility to track changes, such as retinal thinning or thickening. We present the imaging process and analysis with the example of the Opa1delTTAG mouse line. Three types of scans are proposed, with two quantification methods: standard and homemade calipers. The latter is best for use on the peripapillary retina during radial scans; being more precise, is preferable for analyzing thinner structures. All approaches described here are designed for retinal ganglion cells (RGC) but are easily adaptable to other cell populations. In conclusion, OCT is efficient in mouse model phenotyping and has the potential to be used for the reliable evaluation of therapeutic interventions.

Optical Coherence Tomography: Imaging Mouse Retinal Ganglion Cells In Vivo

This manuscript describes a protocol for the in vivo imaging of the mouse retina with high-resolution spectral domain optical coherence tomography (SD-OCT). It focuses on retinal ganglion cells (RGC) in the peripapillary region, with several scanning and quantifying approaches described.

Optische Kohärenztomographie: Maus retinalen Ganglienzellen Zellen In Vivo Imaging

Structural changes in the retina are common manifestations of ophthalmic diseases. Optical coherence tomography (OCT) enables their identification in ...

In Vivo Two-photon Imaging of Cortical Neurons in Neonatal Mice

Two-photon imaging is a powerful tool for the in vivo analysis of neuronal circuits in the mammalian brain. However, a limited number of in vivo imaging methods exist for examining the brain tissue of live newborn mammals. Herein we summarize a protocol for imaging individual cortical neurons in living neonatal mice. This protocol includes the following two methodologies: (1) the Supernova system for sparse and bright labeling of cortical neurons in the developing brain, and (2) a surgical procedure for the fragile neonatal skull. This protocol allows the observation of temporal changes of individual cortical neurites during neonatal stages with a high signal-to-noise ratio. Labeled cell-specific gene silencing and knockout can also be achieved by combining the Supernova with RNA interference and CRISPR/Cas9 gene editing systems. This protocol can, thus, be used for analyzing the developmental dynamics of cortical neurons, molecular mechanisms that control the neuronal dynamics, and changes in neuronal dynamics in disease models.

In Vivo Two-photon Imaging of Cortical Neurons in Neonatal Mice

We present an in vivo two-photon imaging protocol for imaging the cerebral cortex of neonatal mice. This method is suitable for analyzing the developmental dynamics of cortical neurons, the molecular mechanisms that control the neuronal dynamics, and the changes in neuronal dynamics in disease models.

In Vivo Zwei-Photon Imaging der kortikalen Neuronen bei Neugeborenen Mäusen

Two-photon imaging is a powerful tool for the in vivo analysis of neuronal circuits in the mammalian brain. However, a limited number of in vivo imaging ...

Using Optical Coherence Tomography and Optokinetic Response As Structural and Functional Visual System Readouts in Mice and Rats

Optical coherence tomography (OCT) is a fast, non-invasive, interferometric technique allowing high-resolution retinal imaging. It is an ideal tool for the investigation of processes of neurodegeneration, neuroprotection and neuro-repair involving the visual system, as these often correlate well with retinal changes. As a functional readout, visually evoked compensatory eye and head movements are commonly used in experimental models involving the visual function. Combining both techniques allows a quantitative in vivo investigation of structure and function, which can be used to investigate the pathological conditions or to evaluate the potential of novel therapeutics. A great benefit of the presented techniques is the possibility to perform longitudinal analyses allowing the investigation of dynamic processes, reducing variability and cuts down the number of animals needed for the experiments. The protocol described aims to provide a manual for acquisition and analysis of high quality retinal scans of mice and rats using a low cost customized holder with an option to deliver inhalational anesthesia. Additionally, the proposed guide is intended as an instructional manual for researchers using optokinetic response (OKR) analysis in rodents, which can be adapted to their specific needs and interests.

A detailed protocol for the assessment of structural and visual readouts in rodents by optical coherence tomography and optokinetic response is presented. The results provide valuable insights for ophthalmologic as well as neurologic research.

Mit optischen Kohärenztomographie und optokinetischen Antwort als strukturelle und funktionelle visuelles System auslesen bei Mäusen und Ratten

Optical coherence tomography (OCT) is a fast, non-invasive, interferometric technique allowing high-resolution retinal imaging. It is an ideal tool for ...

In Vivo Optical Calcium Imaging of Learning-Induced Synaptic Plasticity in Drosophila melanogaster

Decades of research in many model organisms have led to the current concept of synaptic plasticity underlying learning and memory formation. Learning-induced changes in synaptic transmission are often distributed across many neurons and levels of processing in the brain. Therefore, methods to visualize learning-dependent synaptic plasticity across neurons are needed. The fruit fly Drosophila melanogaster represents a particularly favorable model organism to study neuronal circuits underlying learning. The protocol presented here demonstrates a way in which the processes underlying the formation of associative olfactory memories, i.e., synaptic activity and their changes, can be monitored in vivo. Using the broad array of genetic tools available in Drosophila, it is possible to specifically express genetically encoded calcium indicators in determined cell populations and even single cells. By fixing a fly in place, and opening the head capsule, it is possible to visualize calcium dynamics in these cells whilst delivering olfactory stimuli. Additionally, we demonstrate a set-up in which the fly can be subjected, simultaneously, to electric shocks to the body. This provides a system in which flies can undergo classical olfactory conditioning - whereby a previously na&#239;ve odor is learned to be associated with electric shock punishment - at the same time as the representation of this odor (and other untrained odors) is observed in the brain via two-photon microscopy. Our lab has previously reported the generation of synaptically localized calcium sensors, which enables one to confine the fluorescent calcium signals to pre- or postsynaptic compartments. Two-photon microscopy provides a way to spatially resolve fine structures. We exemplify this by focusing on neurons integrating information from the mushroom body, a higher-order center of the insect brain. Overall, this protocol provides a method to examine the synaptic connections between neurons whose activity is modulated as a result of olfactory learning.

In Vivo Optical Calcium Imaging of Learning-Induced Synaptic Plasticity in Drosophila melanogaster

Here we present a protocol with which pre- and/or postsynaptic calcium can be visualized in the context of Drosophila learning and memory. In vivo calcium imaging using synaptically localized calcium sensors is combined with a classical olfactory conditioning paradigm such that the synaptic plasticity underlying this type of associative learning may be determined.

In Vivo Optische Calcium-Bildgebung der lerninduzierten synaptischen Plastizität bei Drosophila melanogaster

Decades of research in many model organisms have led to the current concept of synaptic plasticity underlying learning and memory formation. ...

Retinal Vascular Reactivity as Assessed by Optical Coherence Tomography Angiography

The vascular supply to the retina has been shown to dynamically adapt through vasoconstriction and vasodilation to accommodate the metabolic demands of the retina. This process, referred to as retinal vascular reactivity (RVR), is mediated by neurovascular coupling, which is impaired very early in retinal vascular diseases such as diabetic retinopathy. Therefore, a clinically feasible method of assessing vascular function may be of significant interest in both research and clinical settings. Recently, in vivo imaging of the retinal vasculature at the capillary level has been made possible by the FDA approval of optical coherence tomography angiography (OCTA), a noninvasive, minimal risk and dyeless angiography method with capillary level resolution. Concurrently, physiological and pathological changes in RVR have been shown by several investigators. The method shown in this manuscript is designed to investigate RVR using OCTA with no need for alterations to the clinical imaging procedures or device. It demonstrates real time imaging of the retina and retinal vasculature during exposure to hypercapnic or hyperoxic conditions. The exam is easily performed with two personnel in under 30 min with minimal subject discomfort or risk. This method is adaptable to other ophthalmic imaging devices and the applications may vary based on the composition of the gas mixture and patient population. A strength of this method is that it allows for an investigation of retinal vascular function at the capillary level in human subjects in vivo. Limitations of this method are largely those of OCTA and other retinal imaging methods including imaging artifacts and a restricted dynamic range. The results obtained from the method are OCT and OCTA images of the retina. These images are amenable to any analysis that is possible on commercially available OCT or OCTA devices. The general method, however, can be adapted to any form of ophthalmic imaging.

This article describes a method for measuring retinal vasculature reactivity in vivo with human subjects using a gas breathing provocation technique to deliver vasoactive stimuli while acquiring retinal images.

Retinale Vaskuläre Reaktivität nach der optischen Kohärenztomographie Angiographie

The vascular supply to the retina has been shown to dynamically adapt through vasoconstriction and vasodilation to accommodate the metabolic demands of ...