Diese Arbeit wurde durch Stipendien der Samsung Science and Technology Foundation (Projektnummer SSTF-BA1801-10) unterstützt.

<ol>
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Der Autor hat nichts zu verraten

Geschickte Operationstechniken sind unerlässlich, um eine erfolgreiche optische Kalzium-Bildgebung in vivo mit Kopf-Mount-Miniaturmikroskopie in tieferen Hirnregionen wie der Amygdala zu erreichen, wie wir sie hier beschrieben haben. Obwohl dieses Protokoll eine Richtlinie für optimierte chirurgische Prozesse der Grundplattenbefestigung und der GRIN-Linsenimplantation bietet, können zusätzliche Optimierungsprozesse für kritische Schritte erforderlich sein. Wie im Protokollabschnitt erwähnt, müssen Amygdala-Koordin...

Kalzium ist ein allgegenwärtiger zweiter Botenstoff, der eine entscheidende Rolle in fast allen Zellfunktionen spielt8. In Neuronen führen Aktionspotentialabschuss und synaptische Sendeleistung zu einer schnellen Veränderung der intrazellulären freien [Ca2+]9,10. Daher bietet die Verfolgung von Kalziumtransienten die Möglichkeit, die neuronale Aktivität zu überwachen. GECIs sind leistungsstarke Werkzeuge, die die Überwachung [Ca2+] in definierten Zellpopulationen und intrazellulären Kompartimenten11,12ermöglichen. Unter vielen verschiedenen Arten von proteinbasiertem Kalziumindikator ist GCaMP, eine Ca2+-Sonde, die auf einem einzigen GFP-Molekül13basiert, die am meisten optimierte und daher am weitesten verbreitete GECI. Durch mehrere Runden des Engineerings wurde eine Reihe von Varianten von GCaMP entwickelt12,14,15,16. Wir verwenden einen der kürzlich entwickelten GCaMPs, GCaMP7b, in diesem Protokoll16. GCaMP-Sensoren haben wesentlich zur Untersuchung der Funktionen des neuronalen Schaltkreises in einer Reihe von Modellorganismen beigetragen, wie z. B. der Abbildung von Ca2+ Transienten während der Entwicklung17, in vivo Bildgebung in einer spezifischen kortikalen Schicht18, Messung der Schaltungsdynamik im Motoraufgabenlernen19 und Bildgebung der Zellensembleaktivität im Zusammenhang mit assoziativem Angstgedächtnis im Hippocampus und Amygdala20,21.
Optische Bildgebung von GECIs hat mehrere Vorteile22. Die genetische Codierung ermöglicht es, GECIs für einen längeren Zeitraum stabil in einer bestimmten Teilmenge von Zellen zu exprimieren, die durch genetisches Profil oder spezifische Muster anatomischer Konnektivität definiert sind. Optische Bildgebung ermöglicht in vivo chronische simultane Überwachung von Hunderten bis Tausenden von Neuronen bei lebenden Tieren. Einige optische Bildgebungssysteme wurden für die In-vivo-Bildgebung und Analyse von GECIs im Gehirn frei verhaltender Mäuse mit miniaturisierten Fluoreszenzmikroskopen21,23,24,25entwickelt. Obwohl die optische Bildgebungstechnik in vivo, die auf GECIs, GRIN-Objektiv und einem Head-Mount-Miniaturmikroskop basiert, ein leistungsfähiges Werkzeug ist, um den Zusammenhang zwischen neuronaler Schaltkreisaktivität und Verhalten zu untersuchen, war die Anwendung dieser Technologie auf die Amygdala aufgrund mehrerer technischer Probleme im Zusammenhang mit der Ausrichtung der GRIN-Linse auf Zellen, die GECIs in der Amygdala exzieren, ohne Bewegungsartefakte zu verursachen, die die Qualität der Bildaufnahme stark reduzieren und Zellen finden, die GECIs exdrücken. Dieses Protokoll soll eine hilfreiche Richtlinie für chirurgische Verfahren der Baseplate-Anhaftung und GRIN-Linsenimplantation bieten, die entscheidende Schritte für eine erfolgreiche optische Kalzium-Bildgebung in vivo in der Amygdala sind. Obwohl dieses Protokoll auf die Amygdala abzielt, sind die meisten hier beschriebenen Verfahren allgemein auf andere tiefere Hirnregionen anwendbar. Obwohl dieses Protokoll auf einem bestimmten System (z. B. Inscopix) basiert, kann derselbe Zweck leicht mit anderen alternativen Systemen erreicht werden.

<table border="0" cellpadding="0" cellspacing="0" style="width:666px;" width="665">
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		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">26G needle</td>
			<td style="width:121px;">BD</td>
			<td align="right" style="width:161px;">302002</td>
			<td style="width:167px;">Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">AAV1-Syn-GCaMP7b-WPRE</td>
			<td style="width:121px;">Addgene</td>
			<td style="width:161px;">104493-AAV1</td>
			<td>Surgery</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:216px;">AAV2/1-CaMKii&#945;-GFP</td>
			<td style="width:121px;">custom made</td>
			<td style="width:161px;"></td>
			<td>Surgery</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Acrylic-Dental cement (Ortho-jet Acrylic Pink)</td>
			<td style="width:121px;">Lang</td>
			<td style="width:161px;">1334-pink</td>
			<td>Surgery &#38; Baseplate Attachment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Air flow manipulator</td>
			<td style="width:121px;">Neurotar</td>
			<td style="width:161px;">NTR000253-04</td>
			<td>Baseplate Attachment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Amoxicillin</td>
			<td style="width:121px;">SIGMA</td>
			<td style="width:161px;">A8523-5G</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Baseplate</td>
			<td style="width:121px;">INSCOPIX</td>
			<td style="width:161px;">1050-002192</td>
			<td>Baseplate Attachment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Baseplate cover</td>
			<td style="width:121px;">INSCOPIX</td>
			<td style="width:161px;">1050-002193</td>
			<td>Baseplate Attachment</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Behavioral apparatus (chamber)</td>
			<td style="width:121px;">Coulbourn Instrument</td>
			<td style="width:161px;">Testcage</td>
			<td>Behavior test</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Behavioral apparatus (software)</td>
			<td style="width:121px;">Coulbourn Instrument</td>
			<td style="width:161px;">Freeze Frame</td>
			<td>Behavior test</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Carbon cage</td>
			<td style="width:121px;">Neurotar</td>
			<td style="width:161px;">180mm x 70mm</td>
			<td>Baseplate Attachment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Carprofen</td>
			<td style="width:121px;">SIGMA</td>
			<td style="width:161px;">PHR1452-1G</td>
			<td>Surgery</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Data processing software</td>
			<td style="width:121px;">INSCOPIX</td>
			<td style="width:161px;">INSCOPIX Data Processing Software</td>
			<td>Baseplate Attachment &#38; Behavior test</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dexamethasone</td>
			<td style="width:121px;">SIGMA</td>
			<td style="width:161px;">D1756-500MG</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Drill</td>
			<td style="width:121px;">Seyang</td>
			<td style="width:161px;">marathon-4</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Drill bur</td>
			<td style="width:121px;">ELA</td>
			<td style="width:161px;">US1/2, Shank104</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glass needle</td>
			<td style="width:121px;">WPI</td>
			<td style="width:161px;">PG10165-4</td>
			<td>Surgery</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">GRIN lens (INSCOPIX Proview Lens Probe)</td>
			<td style="width:121px;">INSCOPIX</td>
			<td style="width:161px;">1050-002208</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hamilton Syringe</td>
			<td style="width:121px;">Hamilton</td>
			<td align="right" style="width:161px;">84875</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Head plate</td>
			<td style="width:121px;">Neurotar</td>
			<td style="width:161px;">Model 5</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hex-key</td>
			<td style="width:121px;">INSCOPIX</td>
			<td style="width:161px;">1050-004195</td>
			<td>Baseplate Attachment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laptop computer</td>
			<td style="width:121px;">Samsung</td>
			<td style="width:161px;">NT950XBV</td>
			<td>Surgery &#38; Baseplate Attachment</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Lens holder, Stereotaxic rod (INSCOPIX proview implant kit)</td>
			<td style="width:121px;">INSCOPIX</td>
			<td style="width:161px;">1050-004223</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Microscope gripper</td>
			<td style="width:121px;">INSCOPIX</td>
			<td style="width:161px;">1050-002199</td>
			<td>Baseplate Attachment</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Microscope, DAQ software, hardware</td>
			<td style="width:121px;">INSCOPIX</td>
			<td style="width:161px;">nVista 3.0</td>
			<td>Baseplate Attachment &#38; Behavior test</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mobile homecage</td>
			<td style="width:121px;">Neurotar</td>
			<td style="width:161px;">MHC V5</td>
			<td>Baseplate Attachment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Moterized arm</td>
			<td style="width:121px;">Neurostar</td>
			<td style="width:161px;">Customized</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Moterized arm software</td>
			<td style="width:121px;">Neurostar</td>
			<td style="width:161px;">Customized</td>
			<td>Surgery</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">NI board</td>
			<td style="width:121px;">National instrument</td>
			<td style="width:161px;"></td>
			<td>Behavior test</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Removable epoxy bond</td>
			<td style="width:121px;">WPI</td>
			<td style="width:161px;">Kwik-Cast</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Resin cement (Super-bond)</td>
			<td style="width:121px;">Sun medical</td>
			<td style="width:161px;">Super bond C&#38;B</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Skull screw</td>
			<td style="width:121px;">Stoelting</td>
			<td align="right" style="width:161px;">51457</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Stereotaxic electrode holder</td>
			<td style="width:121px;">ASI</td>
			<td style="width:161px;">EH-600</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Stereotaxic frame</td>
			<td style="width:121px;">Stoelting</td>
			<td align="right" style="width:161px;">51600</td>
			<td>Surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Stereotaxic manipulator</td>
			<td style="width:121px;">Stoelting</td>
			<td align="right" style="width:161px;">51600</td>
			<td>Baseplate Attachment</td>
		</tr>
	</tbody>
</table>

successful in vivo calcium imaging with a head-mount miniaturized microscope in the amygdala of freely behaving mouse

In vivo Echtzeit-Überwachung von neuronalen Aktivitäten bei frei beweglichen Tieren ist einer der wichtigsten Ansätze, um neuronale Aktivität mit Verhalten zu verknüpfen. Zu diesem Zweck wurde eine in vivo-Bildgebungstechnik entwickelt, die Kalziumtransienten in Neuronen mithilfe genetisch kodierter Calciumindikatoren (GECIs), eines miniaturisierten Fluoreszenzmikroskops und einer Gradienten-Refraktiven-Index-Linse (GRIN) erkennt und erfolgreich auf viele Gehirnstrukturen1,2,3,4,5,6angewendet. Diese bildgebende Technik ist besonders leistungsfähig, da sie eine chronische simultane Bildgebung genetisch definierter Zellpopulationen über einen längeren Zeitraum bis zu mehreren Wochen ermöglicht. Obwohl nützlich, diese bildgebende Technik wurde nicht leicht auf Gehirnstrukturen angewendet, die tief im Gehirn wie Amygdala, eine wesentliche Gehirnstruktur für emotionale Verarbeitung und assoziative Angst Gedächtnis7lokalisieren. Es gibt mehrere Faktoren, die es schwierig machen, die bildgebende Technik auf die Amygdala anzuwenden. Zum Beispiel treten Bewegungsartefakte in der Regel häufiger während der Bildgebung in den tieferen Hirnregionen auf, weil ein tief in das Gehirn implantiertes Kopf-Mount-Mikroskop relativ instabil ist. Ein weiteres Problem ist, dass der seitliche Ventrikel in der Nähe der implantierten GRIN-Linse positioniert ist und seine Bewegung während der Atmung zu hochunregelmäßigen Bewegungsartefakten führen kann, die nicht leicht korrigiert werden können, was es schwierig macht, eine stabile bildgebende Ansicht zu bilden. Da die Zellen in der Amygdala in der Regel in einem ruhenden oder anästhesierten Zustand ruhig sind, ist es schwierig, die Zielzellen, die GECI in der Amygdala exzieren, während des Baseplating-Verfahrens für eine spätere Bildgebung zu finden und zu fokussieren. Dieses Protokoll bietet eine hilfreiche Anleitung, wie zellen, die GECI in der Amygdala exemiten, effizient mit einem miniaturisierten Mikroskop mit Kopfmontage für eine erfolgreiche In-vivo-Calcium-Bildgebung in einer so tieferen Hirnregion gezielt werden können. Es wird darauf hingewiesen, dass dieses Protokoll auf einem bestimmten System (z. B. Inscopix) basiert, aber nicht darauf beschränkt ist.

Validierung der GRIN-Linsenimplantation Bevor die Grundplatte chronisch durch Zementieren am Gehirn befestigt wird, muss die GRIN-Linsenimplantation validiert werden. Bei Tieren mit erfolgreicher Linsenimplantation wurden sowohl GCaMP-Extierzellen als auch Blutgefäße innerhalb eines Fokalebenenbereichs deutlich beobachtet, der durch den Abstand zwischen objektiver Linse des Mikroskops und implantierter GRIN-Linse bestimmt wurde (Abbildung 2Aund...

Watch this Scientific Journal Video about Successful In vivo Calcium Imaging with a Head-Mount Miniaturized Microscope in the Amygdala of Freely Behaving Mouse at JoVE.com

Successful In vivo Calcium Imaging with a Head-Mount Miniaturized Microscope in the Amygdala of Freely Behaving Mouse

In vivo mikroendoskopische Kalzium-Bildgebung ist ein unschätzbares Werkzeug, das Echtzeit-Überwachung von neuronalen Aktivitäten bei frei verhaltenden Tieren ermöglicht. Jedoch, Anwendung dieser Technik auf die Amygdala war schwierig. Dieses Protokoll soll eine nützliche Leitlinie für die erfolgreiche Ausrichtung auf Amygdala-Zellen mit einem miniaturisierten Mikroskop bei Mäusen bieten.

Erfolgreiche In-vivo-Calcium-Bildgebung mit einem kopfmontierten Miniaturmikroskop in der Amygdala der frei verhaltenden Maus

In vivo real-time monitoring of neuronal activities in freely moving animals is one of key approaches to link neuronal activity to behavior. For this ...

successful-vivo-calcium-imaging-with-head-mount-miniaturized

Research

JoVE Journal

Neuroscience

12.0K Aufrufe.  Korea Advanced Institute of Science and Technology (KAIST). In vivo mikroendoskopische Kalzium-Bildgebung ist ein unschätzbares Werkzeug, das Echtzeit-Überwachung von neuronalen Aktivitäten bei frei verhaltenden Tieren ermöglicht. Jedoch, Anwendung dieser Technik auf die Amygdala war schwierig. Dieses Protokoll soll eine nützliche Leitlinie für die erfolgreiche Ausrichtung auf Amygdala-Zellen mit einem miniaturisierten Mikroskop bei Mäusen bieten.

Serie: Successful In vivo Calcium Imaging with a Head-Mount Miniaturized Microscope in the Amygdala of Freely Behaving Mouse

In vivo Neuronal Calcium Imaging in C. elegans

The nematode worm C. elegans is an ideal model organism for relatively simple, low cost neuronal imaging in vivo. Its small transparent body and simple, well-characterized nervous system allows identification and fluorescence imaging of any neuron within the intact animal. Simple immobilization techniques with minimal impact on the animal's physiology allow extended time-lapse imaging. The development of genetically-encoded calcium sensitive fluorophores such as cameleon 1 and GCaMP 2 allow in vivo imaging of neuronal calcium relating both cell physiology and neuronal activity. Numerous transgenic strains expressing these fluorophores in specific neurons are readily available or can be constructed using well-established techniques. Here, we describe detailed procedures for measuring calcium dynamics within a single neuron in vivo using both GCaMP and cameleon. We discuss advantages and disadvantages of both as well as various methods of sample preparation (animal immobilization) and image analysis. Finally, we present results from two experiments: 1) Using GCaMP to measure the sensory response of a specific neuron to an external electrical field and 2) Using cameleon to measure the physiological calcium response of a neuron to traumatic laser damage. Calcium imaging techniques such as these are used extensively in C. elegans and have been extended to measurements in freely moving animals, multiple neurons simultaneously and comparison across genetic backgrounds. C. elegans presents a robust and flexible system for in vivo neuronal imaging with advantages over other model systems in technical simplicity and cost.

In vivo Neuronal Calcium Imaging in C. elegans

With its small transparent body, well-documented neuroanatomy and a host of amenable genetic techniques and reagents, C. elegans makes an ideal model organism for in vivo neuronal imaging using relatively simple, low-cost techniques. Here we describe single neuron imaging within intact adult animals using genetically encoded fluorescent calcium indicators.

In vivo Neuronale Calcium Imaging in C. elegans

The nematode worm C. elegans is an ideal model organism  for relatively simple, low cost neuronal imaging in vivo. Its small transparent body and simple, ...

Forschung

Neurowissenschaften

In Vivo Functional Brain Imaging Approach Based on Bioluminescent Calcium Indicator GFP-aequorin

Functional in vivo imaging has become a powerful approach to study the function and physiology of brain cells and structures of interest. Recently a new method of Ca2+-imaging using the bioluminescent reporter GFP-aequorin (GA) has been developed. This new technique relies on the fusion of the GFP and aequorin genes, producing a molecule capable of binding calcium and&#160;&#8212; with the addition of its cofactor coelenterazine &#8212; emitting bright light that can be monitored through a photon collector. Transgenic lines carrying the GFP-aequorin gene have been generated for both mice and Drosophila. In Drosophila, the GFP-aequorin gene has been placed under the control of the GAL4/UAS binary expression system allowing for targeted expression and imaging within the brain. This method has subsequently been shown to be capable of detecting both inward Ca2+-transients and Ca2+-released from inner stores. Most importantly it allows for a greater duration in continuous recording, imaging at greater depths within the brain, and recording at high temporal resolutions (up to 8.3 msec). Here we present the basic method for using bioluminescent imaging to record and analyze Ca2+-activity within the mushroom bodies, a structure central to learning and memory in the fly brain.

In Vivo Functional Brain Imaging Approach Based on Bioluminescent Calcium Indicator GFP-aequorin

Here we present a novel Ca2+-imaging approach using a bioluminescent reporter. This approach uses a fused construct GFP-aequorin which binds to Ca2+ and emits light, eliminating the need for light excitation. Significantly this method permits long continuous imaging, access to deep brain structures and high temporal resolution.

In Vivo Functional Brain Imaging Ansatz, der auf Bioluminescent Calciumindikator GFP-Aequorin

Functional in vivo imaging has become a powerful approach to study the function and physiology of brain cells and structures of interest. Recently a new ...

Ratiometric Calcium Imaging of Individual Neurons in Behaving Caenorhabditis Elegans

It has become increasingly clear that neural circuit activity in behaving animals differs substantially from that seen in anesthetized or immobilized animals. Highly sensitive, genetically encoded fluorescent reporters of Ca2+ have revolutionized the recording of cell and synaptic activity using non-invasive optical approaches in behaving animals. When combined with genetic and optogenetic techniques, the molecular mechanisms that modulate cell and circuit activity during different behavior states can be identified.
Here we describe methods for ratiometric Ca2+ imaging of single neurons in freely behaving Caenorhabditis elegans worms. We demonstrate a simple mounting technique that gently overlays worms growing on a standard Nematode Growth Media (NGM) agar block with a glass coverslip, permitting animals to be recorded at high-resolution during unrestricted movement and behavior. With this technique, we use the sensitive Ca2+ reporter GCaMP5 to record changes in intracellular Ca2+ in the serotonergic Hermaphrodite Specific Neurons (HSNs) as they drive egg-laying behavior. By co-expressing mCherry, a Ca2+-insensitive fluorescent protein, we can track the position of the HSN within ~ 1 &#181;m and correct for fluctuations in fluorescence caused by changes in focus or movement. Simultaneous, infrared brightfield imaging allows for behavior recording and animal tracking using a motorized stage. By integrating these microscopic techniques and data streams, we can record Ca2+ activity in the C. elegans egg-laying circuit as it progresses between inactive and active behavior states over tens of minutes.

Ratiometric Calcium Imaging of Individual Neurons in Behaving Caenorhabditis Elegans

This protocol describes the use of genetically encoded Ca2+ reporters to record changes in neural activity in behaving Caenorhabditis elegans worms. &#8195;

Ratiometrischen Kalzium Imaging einzelner Neuronen im Verhalten Caenorhabditis Elegans

It has become increasingly clear that neural circuit activity in behaving animals differs substantially from that seen in anesthetized or immobilized ...

Long-term Sensory Conflict in Freely Behaving Mice

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

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

Langfristige sensorischen Konflikt in Mäusen frei Verhalten

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

Transpupillary Two-Photon In Vivo Imaging of the Mouse Retina

The retina transforms light signals from the environment into electrical signals that are propagated to the brain. Diseases of the retina are prevalent and cause visual impairment and blindness. Understanding how such diseases progress is critical to formulating new treatments. In vivo&#160;microscopy in animal models of disease is a powerful tool for understanding neurodegeneration and has led to important progress towards treatments of conditions ranging from Alzheimer&#39;s disease to stroke. Given that the retina is the only central nervous system structure inherently accessible by optical approaches, it naturally lends itself towards in vivo imaging. However, the native optics of the lens and cornea present some challenges for effective imaging access.
This protocol outlines methods for in vivo two-photon imaging of cellular cohorts and structures in the mouse retina at cellular resolution, applicable for both acute- and chronic-duration imaging experiments. It presents examples of retinal ganglion cell (RGC), amacrine cell, microglial, and vascular imaging using a suite of labeling techniques including adeno-associated virus (AAV) vectors, transgenic mice, and inorganic dyes. Importantly, these techniques extend to all cell types of the retina, and suggested methods for accessing other cellular populations of interest are described. Also detailed are example strategies for manual image postprocessing for display and quantification. These techniques are directly applicable to studies of retinal function in health and disease.

In vivo imaging is a powerful tool for the study of biology in health and disease. This protocol describes transpupillary imaging of the mouse retina with a standard two-photon microscope. It also demonstrates different in vivoimaging methods to fluorescently label multiple cellular cohorts of the retina.

Transpupille Zwei-Photonen-In-vivo-Bildgebung der Netzhaut der Maus

The retina transforms light signals from the environment into electrical signals that are propagated to the brain. Diseases of the retina are prevalent ...

In vivo Calcium Imaging of Mouse Geniculate Ganglion Neuron Responses to Taste Stimuli

Within the last ten years, advances in genetically encoded calcium indicators (GECIs) have promoted a revolution in in vivo functional imaging. Using calcium as a proxy for neuronal activity, these techniques provide a way to monitor the responses of individual cells within large neuronal ensembles to a variety of stimuli in real time. We, and others, have applied these techniques to image the responses of individual geniculate ganglion neurons to taste stimuli applied to the tongues of live anesthetized mice. The geniculate ganglion is comprised of the cell bodies of gustatory neurons innervating the anterior tongue and palate as well as some somatosensory neurons innervating the pinna of the ear. Imaging the taste-evoked responses of individual geniculate ganglion neurons with GCaMP has provided important information about the tuning profiles of these neurons in wild-type mice as well as a way to detect peripheral taste miswiring phenotypes in genetically manipulated mice. Here we demonstrate the surgical procedure to expose the geniculate ganglion, GCaMP fluorescence image acquisition, initial steps for data analysis, and troubleshooting. This technique can be used with transgenically encoded GCaMP, or with AAV-mediated GCaMP expression, and can be modified to image particular genetic subsets of interest (i.e., Cre-mediated GCaMP expression). Overall, in vivo calcium imaging of geniculate ganglion neurons is a powerful technique for monitoring the activity of peripheral gustatory neurons and provides complementary information to more traditional whole-nerve chorda tympani recordings or taste behavior assays.

Here we present how to expose the geniculate ganglion of a live, anesthetized laboratory mouse and how to use calcium imaging to measure the responses of ensembles of these neurons to taste stimuli, allowing for multiple trials with different stimulants. This allows for in depth comparisons of which neurons respond to which tastants.

In vivo Calcium Imaging of Mouse Geniculate Ganglion Neuron Reaktionen auf Geschmacksreize

Within the last ten years, advances in genetically encoded calcium indicators (GECIs) have promoted a revolution in in vivo functional imaging. Using ...

In vivo Calcium Imaging in Mouse Inferior Olive

Inferior olive (IO), a nucleus in the ventral medulla, is the only source of climbing fibers that form one of the two input pathways entering the cerebellum. IO has long been proposed to be crucial for motor control and its activity is currently considered to be at the center of many hypotheses of both motor and cognitive functions of the cerebellum. While its physiology and function have been relatively well studied on single-cell level in vitro, presently there are no reports on the organization of the IO network activity in living animals. This is largely due to the extremely challenging anatomical location of the IO, making it difficult to subject to conventional fluorescent imaging methods, where an optic path must be created through the entire brain located dorsally to the region of interest.
Here we describe an alternative method for obtaining state-of-the-art -level calcium imaging data from the IO network. The method takes advantage of the extreme ventral location of the IO and involves a surgical procedure for inserting a gradient-refractive index (GRIN) lens through the neck viscera to come into contact with the ventral surface of the calcium sensor GCaMP6s-expressing IO in anesthetized mice. A representative calcium imaging recording is shown to demonstrate the feasibility to record IO neuron activity after the surgery. While this is a non-survival surgery and the recordings must be conducted under anesthesia, it avoids damage to life-critical brainstem nuclei and allows conducting large variety of experiments investigating spatiotemporal activity patterns and input integration in the IO. This procedure with modifications could be used for recordings in other, adjacent regions of the ventral brainstem.

In vivo Calcium Imaging in Mouse Inferior Olive

We present a protocol to expose the brainstem of adult mouse from the ventral side. By using a gradient-refractive index lens with a miniature microscope, calcium imaging can be used to examine the activity of inferior olive neural somata in vivo.

In vivo Calcium Imaging in Maus Inferior Olive

Inferior olive (IO), a nucleus in the ventral medulla, is the only source of climbing fibers that form one of the two input pathways entering the ...

In Vivo Wide-Field and Two-Photon Calcium Imaging from a Mouse Using a Large Cranial Window

Wide-field calcium imaging from the mouse&#39;s neocortex allows one to observe cortex-wide neural activity related to various brain functions. On the other hand, two-photon imaging can resolve the activity of local neural circuits at the single-cell level. It is critical to make a large cranial window to perform multiple-scale analysis using both imaging techniques in the same mouse. To achieve this, one must remove a large section of the skull and cover the exposed cortical surface with transparent materials. Previously, glass skulls and polymer-based cranial windows have been developed for this purpose, but these materials are not easily fabricated. The present protocol describes a simple method for making a large cranial window consisting of commercially available polyvinylidene chloride (PVDC) wrapping film, a transparent silicone plug, and a cover glass. For imaging the dorsal surface of an entire hemisphere, the window size was approximately 6 x 3 mm2. Severe brain vibrations were not observed regardless of such a large window. Importantly, the condition of the brain surface did not deteriorate for more than one month. Wide-field imaging of a mouse expressing a genetically-encoded calcium indicator (GECI), GCaMP6f, specifically in astrocytes, revealed synchronized responses in a few millimeters. Two-photon imaging of the same mouse showed prominent calcium responses in individual astrocytes over several seconds. Furthermore, a thin layer of an adeno-associated virus was applied to the PVDC film and successfully expressed GECI in cortical neurons over the cranial window. This technique is reliable and cost-effective for making a large cranial window and facilitates the investigation of the neural and glial dynamics and their interactions during behavior at the macroscopic and microscopic levels.

In Vivo Wide-Field and Two-Photon Calcium Imaging from a Mouse Using a Large Cranial Window

The present protocol describes making a large (6 x 3 mm2) cranial window using food wrap, transparent silicone, and cover glass. This cranial window allows in vivo wide-field and two-photon calcium imaging experiments in the same mouse.

Im lebenden Organismus Weitfeld- und Zwei-Photonen-Kalzium-Bildgebung einer Maus mit einem großen Schädelfenster

Wide-field calcium imaging from the mouse&#39;s neocortex allows one to observe cortex-wide neural activity related to various brain functions. On the ...

In Vivo Calcium Imaging of Neuronal Ensembles in Networks of Primary Sensory Neurons in Intact Dorsal Root Ganglia

Ca2+ imaging can be used as a proxy for cellular activity, including action potentials and various signaling mechanisms involving Ca2+ entry into the cytoplasm or the release of intracellular Ca2+ stores. Pirt-GCaMP3-based Ca2+ imaging of primary sensory neurons of the dorsal root ganglion (DRG) in mice offers the advantage of simultaneous measurement of a large number of cells. Up to 1,800 neurons can be monitored, allowing neuronal networks and somatosensory processes to be studied as an ensemble in their normal physiological context at a populational level in vivo. The large number of neurons monitored allows the detection of activity patterns that would be challenging to detect using other methods. Stimuli can be applied to the mouse hindpaw, allowing the direct effects of stimuli on the DRG neuron ensemble to be studied. The number of neurons producing Ca2+ transients as well as the amplitude of Ca2+ transients indicates sensitivity to specific sensory modalities. The diameter of neurons provides evidence of activated fiber types (non-noxious mechano vs. noxious pain fibers, A&#946;, A&#948;, and C fibers). Neurons expressing specific receptors can be genetically labeled with td-Tomato and specific Cre recombinases together with Pirt-GCaMP. Therefore, Pirt-GCaMP3 Ca2+ imaging of DRG provides a powerful tool and model for the analysis of specific sensory modalities and neuron subtypes acting as an ensemble at the populational level to study pain, itch, touch, and other somatosensory signals.

In Vivo Calcium Imaging of Neuronal Ensembles in Networks of Primary Sensory Neurons in Intact Dorsal Root Ganglia

This protocol describes the surgical exposure of the dorsal root ganglion (DRG) followed by GCaMP3 (genetically-encoded Ca2+ indicator; Green Fluorescent Protein-Calmodulin-M13 Protein 3) Ca2+ imaging of the neuronal ensembles using Pirt-GCaMP3 mice while applying a variety of stimuli to the ipsilateral hind paw.

Im lebenden Organismus Calcium-Bildgebung neuronaler Ensembles in Netzwerken primärer sensorischer Neurone in intakten dorsalen Wurzelganglien

Ca2+ imaging can be used as a proxy for cellular activity, including action potentials and various signaling mechanisms involving Ca2+ entry into the ...

Subcellular Imaging of Neuronal Calcium Handling In Vivo

Calcium (Ca2+) imaging has been largely used to examine neuronal activity, but it is becoming increasingly clear that subcellular Ca2+ handling is a crucial component of intracellular signaling. The visualization of subcellular Ca2+ dynamics in vivo,&#160;where neurons can be studied in their native, intact circuitry, has proven technically challenging in complex nervous systems. The transparency and relatively simple nervous system of the nematode Caenorhabditis elegans enable the cell-specific expression and in vivo visualization of fluorescent tags and indicators. Among these are fluorescent indicators that have been modified for use in the cytoplasm as well as various subcellular compartments, such as the mitochondria. This protocol enables non-ratiometric Ca2+ imaging in vivo with a subcellular resolution that permits the analysis of Ca2+ dynamics down to the level of individual dendritic spines and mitochondria. Here, two available genetically encoded indicators with different Ca2+ affinities are used to demonstrate the use of this protocol for measuring relative Ca2+ levels within the cytoplasm or mitochondrial matrix in a single pair of excitatory interneurons (AVA). Together with the genetic manipulations and longitudinal observations possible in C. elegans, this imaging protocol may be useful for answering questions regarding how Ca2+ handling regulates neuronal function and plasticity.

Subcellular Imaging of Neuronal Calcium Handling In Vivo

The current methods describe a non-ratiometric approach for high-resolution, sub-compartmental calcium imaging in vivo in Caenorhabditis elegans using readily available genetically encoded calcium indicators.

Subzelluläre Bildgebung des neuronalen Calcium-Handlings in vivo

Calcium (Ca2+) imaging has been largely used to examine neuronal activity, but it is becoming increasingly clear that subcellular Ca2+ handling is a ...