Diese Arbeit wurde von der Canadian Institute of Health Research unterstützt.

Die Experimente untersucht den Beitrag des Hippocampus zu Pilotierung gegenüber Koppelnavigation durch die Nutzung einer neuen Aufgabe in der Ratten challanged nach Hause nach einer Hinfahrt nach einem duftenden String aus ihrer Zuflucht zu einem Lebensmittel Pellet am Ende der Zeichenfolge befindet zurückkehren konnten. Kontrollratten navigiert effizient sowohl mit räumlichen und Koppelnavigation Strategien. Die Ratten, die mit Fimbria-Fornix Läsionen erfolgreich navigiert mit Hilfe eines räumlichen Strategie wurden aber beeinträchtigt, wenn gezwungen, Koppelnavigation verwenden. Diese Ergebnisse sind konsistent mit der Hypothese, dass die Integrität des Hippokampus wesentlich für Koppelnavigation ist. Dies kann auch die erste Demonstration in Verfolgung in einem anderen Tieren als den Hund werden. Task-Anforderungen Das Neuartige an dieser Studie war die Verwendung eines duftenden String, der die Subjekte zu einer Duftspur, um ein Lebensmittel Pellet track erlaubt. Der Einsatz von Tracking ermöglicht eine Analyse der Ratten &quot;Homing Verhalten in eine Reihe von Möglichkeiten. Zunächst werden die Ratten &quot;Hinweg und die Cue angegeben. Ratten sind durchaus in der Lage mit Oberfläche Geruchssinn (Maaswinkel und Whishaw, 1999), und so den Einsatz eines duftenden String zwingt sie zu einem bestimmten Stichwort zu konzentrieren. Zweitens könnten alle Ratten, die mit genau der gleichen Hinfahrt vorgestellt werden. Dadurch wird die Variabilität, die, wenn sie zufällig und individuell nach außen Strecken auf der Suche nach dem Zufallsprinzip angeordnet Nahrung zu sich nehmen auftritt. Der dritte ein wichtiges Merkmal des Verfahrens ist, dass es möglich war, um zu bestimmen, wenn die Ratten eingeschaltet Cues und Navigation Strategien zwischen den Hin-und Heimreise. Im Zuge der Studie erhielten die Ratten eine große Anzahl von Problemen nachzugehen, die lineare Strecken, Polygone Tracks und einem achteckigen Track enthalten. Was war in all der Probleme, jedoch war der Vergleich zwischen den Ratten die Fähigkeit, nach Hause zu navigieren, wenn sie könnten räumliche Cues (Seh-oder Geruchssinn) und ihre Fähigkeit zu verwenden, um zu Hause mit Koppelnavigation Cues (wenn die Augen verbunden oder wieder hergestellt wurde getestet in Infrarotlicht). Cue verwenden Wenn sie gesichtet wurden, reisten sowohl die Steuerung und die Fimbria-Fornix Ratten relativ direkt nach Hause einen Umweg Hinfahrt. Dabei verwendet sie wahrscheinlich stabil visuellen Raum Hinweise zu ihrer Heimatbasis zurückkehren. Wenn die Augen verbunden und präsentiert mit einem Polygon Track, den Kontrollratten dauerte noch einen direkten Weg nach Hause, ohne auf die Witterung zu verfolgen und somit &quot;Schließen des Polygons.&quot; Dabei haben sie wahrscheinlich waren die Integration der Eigenbewegung Hinweise auf der Hinfahrt generiert. Im Gegensatz zu der Fähigkeit der Kontrollratten von einer räumlichen eine Koppelnavigation Strategie wechseln, war der Fimbria-Fornix Ratten Beeinträchtigung in idiothetischen Navigation krass zum Vorschein, wenn sie Augenbinden trugen oder wurden im infraroten Licht getestet. Anstatt einen direkten Weg nach Hause nach einem Polygon Spur zog sie den Duft zu verfolgen und nachvollziehen ihren Weg zurück zum Ausgangspunkt. Folglich wurde ihre homebound Route als Umweg, als ihre Outbound-Route. Das war nicht einfach eine Frage der bequem &quot;unter einen einfachen Weg nach Hause.&quot; Wenn der Duft Track entfernt wurde, wurde der Fimbria-Fornix Ratten desorientiert, aßen ihre Nahrung auf den Tisch, und dann ging um fast zufällig, bis sie die Hütte wieder. So ist in einer Situation, in der sie gezwungen, eine Koppelnavigation Strategie zu verwenden waren, wurden sie nicht in der Lage, dies zu tun. Dieses Ergebnis nicht den Vorschlag, dass Hippocampus Ratten bevorzugt einen Koppelnavigation Strategie (Pearce et al., 1998) zu bestätigen. Abschluss Die aktuelle Forschung zeigt, dass der Hippocampus einige zentrale Rolle spielt in räumliche Verhalten [siehe aber Squire (1992)], aber es gibt unterschiedliche Auffassungen über diese Rolle (O&#39;Keefe und Nadel, 1978; Worden, 1992;. Muller et al, 1996; Whishaw und Maaswinkel, 1998). Der vorliegende Befund unterstützt die Idee, dass der Hippocampus eine Rolle in Koppelnavigation spielt. Diese Schlussfolgerung steht im Einklang mit früheren Vorschläge, dass der Hippocampus eine angeborene räumlichen Rahmen, in dem es Vektoren zwischen den Punkten (Whishaw et al, 1995a, b, 1997.; McNaughton et al, 1996;. Samsonovich und McNaughton, 1997) erzeugen können, enthält. Obwohl die vorliegenden Ergebnisse eine Rolle für den Hippocampus in Koppelnavigation, sind sie nicht endgültig bei der Vergabe dieses als eine exklusive Funktion. Hippocampus Tiere sind auch in das Erlernen neuer räumliche Probleme in der die Anforderungen des Arbeitsgedächtnisses sind hoch beeinträchtigt (Shapiro und O&#39;Connor, 1992; Angeli et al, 1993;. Whishaw und Jarrard, 1995, 1996). Dies kann bedeuten, dass Koppelnavigation Informationen Hilfen beim Übergang zwischen einem Problem und der nächste (Whishaw et al., 1997), oder es kann darauf hingewiesen, dass die Beeinträchtigung in Koppelnavigation ist nur ein Aspekteines allgemeinen Hippokampus-Funktion in das räumliche Verhalten und Gedächtnis (O&#39;Keefe und Nadel, 1978).

<table><tbody><tr><td>Sodium pentobarbital</td><td> Reagent</td><td>Sigma-Aldrich</td><td>p3761-25g</td><td></td></tr><tr><td>Atropine methyl nitrate</td><td>Reagent</td><td>Sigma-Aldrich</td><td>a0382-5g</td><td></td></tr><tr><td>Rodent pellets</td><td>Animal food</td><td>BIO-SERV</td><td></td><td></td></tr></tbody></table>

a video demonstration of preserved piloting by scent tracking but impaired dead reckoning after fimbria-fornix lesions in the rat

Pilotierung und Koppelnavigation Strategien verwenden sehr unterschiedliche Cue Konstellationen und Rechenprozesse (Darwin, 1873; Barlow, 1964; O&#39;Keefe und Nadel, 1978; Mittelstaedt und Mittelstaedt, 1980; Landeau et al, 1984;. Etienne, 1987; Gallistel, 1990; Maurer und Seguinot, 1995). Pilotierung erfordert die Verwendung der Beziehungen zwischen den relativ stabilen externen (Seh-, Geruchs-, Hör-) Signale, während Koppelnavigation erfordert die Integration von Cues durch Selbst-Bewegung erzeugt. Tiere erhalten Eigenbewegung Informationen von vestibulären Rezeptoren und möglicherweise Muskel-und Gelenkschmerzen Rezeptoren und Efferenzkopie von Befehlen, die Bewegung zu erzeugen. Ein Tier kann auch die Ströme der visuelle, auditive und olfaktorische Reize durch seine Bewegungen verursachten. Mit einem Pilotprojekt Strategie eines Tieres können geometrische Berechnungen Richtungen und Entfernungen zu Orten in ihrer Umgebung zu bestimmen, während mit einer Koppelnavigation Strategie kann Hinweise durch seine früheren Bewegungen erzeugt werden, um zu einer gerechten linken Position zurückkehren zu integrieren. Koppelnavigation wird umgangssprachlich als &quot;Gefühl für die Richtung&quot; und &quot;Gefühl der Distanz.&quot; Zwar gibt es deutliche Hinweise, dass der Hippocampus bei der Steuerung (O&#39;Keefe und Nadel, 1978; O&#39;Keefe und Speakman, 1987) beteiligt ist, gibt es auch Hinweise aus der Verhaltensforschung (Whishaw et al, 1997;. Whishaw und Maaswinkel, 1998; Maaswinkel und Whishaw, 1999), Modellierung (Samsonovich und McNaughton, 1997) und elektrophysiologische (O&#39;Mare et al, 1994;. Sharp et al, 1995;. Taube und Burton, 1995; Blair und Sharp, 1996; McNaughton et al ., 1996; Wiener, 1996; Golob und Taube, 1997) Studien, die den Hippokampus in Koppelnavigation beteiligt ist. Der relative Beitrag des Hippocampus, die beiden Formen der Navigation ist noch ungewiss, jedoch. Normalerweise ist es schwierig, sicher sein, dass ein Tier mit einem Pilotprojekt im Vergleich zu einer Koppelnavigation Strategie, da die Tiere sehr flexibel sind in ihrer Verwendung von Strategien und Cues (Etienne et al, 1996;. Dudchenko et al, 1997;. Martin et al ., 1997; Maaswinkel und Whishaw, 1999). Das Ziel der vorliegenden Video-Demonstrationen war es, das Problem der Cue-Spezifikation zu lösen, um den relativen Beitrag des Hippokampus in der Verwendung dieser Strategien zu untersuchen. Die Ratten wurden in eine neue Aufgabe, in der sie gefolgt linear oder Polygon duftenden Pfade zu einem großen Lebensmittel-Pellets auf einem offenen Feld versteckt erhalten geschult. Weil Ratten haben eine Neigung zum Essen Rücken zu tragen, die Zuflucht, die Genauigkeit und die Hinweise verwendet, um auf der Heimatbasis zurückkehren konnten abhängigen Variablen (Whishaw und Tomie, 1997). Um zu erzwingen, ein Tier aa Koppelnavigation Strategie nutzen, um ihre Zuflucht mit der Nahrung zu erreichen, wurden die Ratten getestet, wenn die Augen verbunden oder unter Infrarot-Licht eine spektrale Wellenlänge, in denen sie nicht sehen können, und in einigen Experimenten wurde die Duftspur wurde zusätzlich entfernt, sobald ein Tier erreichte das Essen. Um den relativen Beitrag des Hippocampus, Fimbria-Fornix (FF) Läsionen, die den Informationsfluss in der Hippocampus-Formation (Bland, 1986) zu stören zu untersuchen, beeinträchtigt Speicher (Gaffan und Gaffan, 1991), und produzieren räumliche Defizite (Whishaw und Jarrard, 1995), verwendet wurden.

Watch this Scientific Journal Video about A Video Demonstration of Preserved Piloting by Scent Tracking but Impaired Dead Reckoning After Fimbria-Fornix Lesions in the Rat at JoVE.com

A Video Demonstration of Preserved Piloting by Scent Tracking but Impaired Dead Reckoning After Fimbria-Fornix Lesions in the Rat

In einem Pilotprojekt Duft Tracking Aufgabe, die Fähigkeit der Ratten zu einem Refugium mit Lebensmitteln zurück mit visuellen einen Geruch Weg oder über Koppelnavigation in Infrarotlicht, demonstriert die integrierte Aufzeichnung der früheren Bewegungen, dass der Hippocampus, die für Koppelnavigation ist.

Eine Video-Demonstration der Preserved Pilotierung von Scent-Tracking aber Impaired Dead Reckoning Nach Fimbria-Fornix Läsionen in der Ratte

Piloting and dead reckoning navigation strategies use very different cue constellations and computational processes (Darwin, 1873; Barlow, 1964; ...

a-video-demonstration-preserved-piloting-scent-tracking-but-impaired

Universidad San Sebastian

Research

JoVE Journal

Biology

11.8K Aufrufe.  Canadian Centre for Behavioural Neuroscience, University of Lethbridge. In einem Pilotprojekt Duft Tracking Aufgabe, die Fähigkeit der Ratten zu einem Refugium mit Lebensmitteln zurück mit visuellen einen Geruch Weg oder über Koppelnavigation in Infrarotlicht, demonstriert die integrierte Aufzeichnung der früheren Bewegungen, dass der Hippocampus, die für Koppelnavigation ist.

Serie: A Video Demonstration of Preserved Piloting by Scent Tracking but Impaired Dead Reckoning After Fimbria-Fornix Lesions in the Rat

The Double-H Maze: A Robust Behavioral Test for Learning and Memory in Rodents

Spatial cognition research in rodents typically employs the use of maze tasks, whose attributes vary from one maze to the next. These tasks vary by their behavioral flexibility and required memory duration, the number of goals and pathways, and also the overall task complexity. A confounding feature in many of these tasks is the lack of control over the strategy employed by the rodents to reach the goal, e.g., allocentric (declarative-like) or egocentric (procedural) based strategies. The double-H maze is a novel water-escape memory task that addresses this issue, by allowing the experimenter to direct the type of strategy learned during the training period. The double-H maze is a transparent device, which consists of a central alleyway with three arms protruding on both sides, along with an escape platform submerged at the extremity of one of these arms.
Rats can be trained using an allocentric strategy by alternating the start position in the maze in an unpredictable manner (see protocol 1; &#167;4.7), thus requiring them to learn the location of the platform based on the available allothetic cues. Alternatively, an egocentric learning strategy (protocol 2; &#167;4.8) can be employed by releasing the rats from the same position during each trial, until they learn the procedural pattern required to reach the goal. This task has been proven to allow for the formation of stable memory traces.
Memory can be probed following the training period in a misleading probe trial, in which the starting position for the rats alternates. Following an egocentric learning paradigm, rats typically resort to an allocentric-based strategy, but only when their initial view on the extra-maze cues differs markedly from their original position. This task is ideally suited to explore the effects of drugs/perturbations on allocentric/egocentric memory performance, as well as the interactions between these two memory systems.

The goal of this protocol is to investigate spatial cognition in rodents. The double-H water maze is a novel test, which is particularly useful to elucidate the different components of learning, consolidation and memory, as well as the interplay of memory systems.

Die Doppel-H Maze: A Robust Verhaltenstest für Lernen und Gedächtnis in Nagetiere

Spatial cognition research in rodents typically employs the use of maze tasks, whose attributes vary from one maze to the next. These tasks vary by their ...

Forschung

Verhalten

Assessing Spatial Memory Impairment in a Mouse Model of Traumatic Brain Injury Using a Radial Water Tread Maze

Despite the recent increase in use of mouse models in scientific research, researchers continue to use cognitive tasks that were originally designed and validated for rat use. The Radial Water Tread (RWT) maze test of spatial memory (designed specifically for mice and requiring no swimming) has been shown previously to successfully distinguish between controlled cortical impact-induced TBI mice and sham controls. Here, a detailed protocol for this task is presented. The RWT maze capitalizes on the natural tendency of mice to avoid open areas in favor of hugging the sides of an apparatus (thigmotaxis). The walls of the maze are lined with nine escape holes placed above the floor of the apparatus, and mice are trained to use visual cues to locate the escape hole that leads out of the maze. The maze is filled with an inch of cold water, sufficient to motivate escape but not deep enough to require that the mouse swim. The acquisition period takes only four training days, with a test of memory retention on day five and a long-term memory test on day 12. The results reported here suggest that the RWT maze is a feasible alternative to rat-validated, swimming-based cognitive tests in the assessment of spatial memory deficits in mouse models of TBI.

Here we present a protocol for a mouse-specific test of cognition that does not require swimming. This test can be used to successfully distinguish controlled cortical impact-induced traumatic brain injury mice from sham controls.

Beurteilung der räumlichen Gedächtnisstörung in einem Mausmodell der traumatischen Gehirnverletzung unter Verwendung eines Radialwasserlaufstreifens

Despite the recent increase in use of mouse models in scientific research, researchers continue to use cognitive tasks that were originally designed and ...

Detecting Behavioral Deficits in Rats After Traumatic Brain Injury

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, few studies have investigated the long-term effects of injury in rodent models of TBI. Shown here are behavioral measures that are well-established in TBI research for times early after injury, such as two weeks, until two months. Some of these methods have previously been used at later times after injury, up to one year, but by very few laboratories. The methods demonstrated here are a short neurological assessment to test reflexes, a Beam-Balance to test balance, a Beam-Walk to test balance and motor coordination, and a working memory version of the Morris water maze that can be sensitive to deficits in reference memory. Male rats were handled and pre-trained to neurological, balance, and motor coordination tests prior to receiving parasagittal fluid percussion injury (FPI) or sham injury. Rats can be tested on the short neurological assessment (neuroscore), the beam-balance, and the Beam-Walk multiple times, while testing on the water maze can only be done once. This difference is because rats can remember the task, thus confounding the results if repeated testing is attempted in the same animal. When testing from one to three days after injury, significant differences are detected in all three non-cognitive tasks. However, differences in the Beam-Walk task were not detectable at later time points (after 3 months). Deficits were detected at 3 months in the Beam-Balance and at 6 months in the neuroscore. Deficits in working memory were detected out to 12 months after injury, and a deficit in a reference memory first appeared at 12 months. Thus, standard behavioral tests can be useful measures of persistent behavioral deficits after FPI.

The goal of the behavioral tests presented here is to detect functional deficits in rats after traumatic brain injury. Four specific tests are presented that detect deficits in behaviors to reflect the damage to specific brain areas at times extending to one year after injury.

Erkennung von Verhaltensstörungen Defizite bei Ratten nach Schädel-Hirn-Verletzung

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, ...

The Dig Task: A Simple Scent Discrimination Reveals Deficits Following Frontal Brain Damage

Cognitive impairment is the most frequent cause of disability in humans following brain damage, yet the behavioral tasks used to assess cognition in rodent models of brain injury is lacking. Borrowing from the operant literature our laboratory utilized a basic scent discrimination paradigm1-4 in order to assess deficits in frontally-injured rats. Previously we have briefly described the Dig task and demonstrated that rats with frontal brain damage show severe deficits across multiple tests within the task5. Here we present a more detailed protocol for this task. Rats are placed into a chamber and allowed to discriminate between two scented sands, one of which contains a reinforcer. The trial ends after the rat either correctly discriminates (defined as digging in the correct scented sand), incorrectly discriminates, or 30 sec elapses. Rats that correctly discriminate are allowed to recover and consume the reinforcer. Rats that discriminate incorrectly are immediately removed from the chamber. This can continue through a variety of reversals and novel scents. The primary analysis is the accuracy for each scent pairing (cumulative proportion correct for each scent). The general findings from the Dig task suggest that it is a simple experimental preparation that can assess deficits in rats with bilateral frontal cortical damage compared to rats with unilateral parietal damage. The Dig task can also be easily incorporated into an existing cognitive test battery. The use of more tasks such as this one can lead to more accurate testing of frontal function following injury, which may lead to therapeutic options for treatment. All animal use was conducted in accordance with protocols approved by the Institutional Animal Care and Use Committee.

In this protocol, a novel application of scent discrimination is described. The Dig task is a reasonably inexpensive task that can be used to assess frontally-mediated cognition following brain damage.

The Dig Aufgabe: A Simple Scent Discrimination enthüllt Defizite Nach Frontal Brain Damage

Cognitive impairment is the most frequent cause of disability in humans following brain damage, yet the behavioral tasks used to assess cognition in ...

Neurowissenschaften

Tracking Rats in Operant Conditioning Chambers Using a Versatile Homemade Video Camera and DeepLabCut

Operant conditioning chambers are used to perform a wide range of behavioral tests in the field of neuroscience. The recorded data is typically based on the triggering of lever and nose-poke sensors present inside the chambers. While this provides a detailed view of when and how animals perform certain responses, it cannot be used to evaluate behaviors that do not trigger any sensors. As such, assessing how animals position themselves and move inside the chamber is rarely possible. To obtain this information, researchers generally have to record and analyze videos. Manufacturers of operant conditioning chambers can typically supply their customers with high-quality camera setups. However, these can be very costly and do not necessarily fit chambers from other manufacturers or other behavioral test setups. The current protocol describes how to build an inexpensive and versatile video camera using hobby electronics components. It further describes how to use the image analysis software package DeepLabCut to track the status of a strong light signal, as well as the position of a rat, in videos gathered from an operant conditioning chamber. The former is a great aid when selecting short segments of interest in videos that cover entire test sessions, and the latter enables analysis of parameters that cannot be obtained from the data logs produced by the operant chambers.

This protocol describes how to build a small and versatile video camera, and how to use videos obtained from it to train a neural network to track the position of an animal inside operant conditioning chambers. This is a valuable complement to standard analyses of data logs obtained from operant conditioning tests.

Tracking Ratten in Operant Conditioning Chambers mit einer vielseitigen hausgemachten Videokamera und DeepLabCut

Operant conditioning chambers are used to perform a wide range of behavioral tests in the field of neuroscience. The recorded data is typically based on ...

Motor and Hippocampal Dependent Spatial Learning and Reference Memory Assessment in a Transgenic Rat Model of Alzheimer's Disease with Stroke

Alzheimer&#39;s disease (AD) is a debilitating neurodegenerative disease that results in neurodegeneration and memory loss. While age is a major risk factor for AD, stroke has also been implicated as a risk factor and an exacerbating factor. The co-morbidity of stroke and AD results in worsened stroke-related motor control and AD-related cognitive deficits when compared to each condition alone. To model the combined condition of stroke and AD, a novel transgenic rat model of AD, with a mutated form of amyloid precursor protein (a key protein involved in the development of AD) incorporated into its DNA, is given a small unilateral striatal stroke.
For a model with the combination of both stroke and AD, behavioral tests that assess stroke-related motor control, locomotion and AD-related cognitive function must be implemented. The cylinder task involves a cost-efficient, multipurpose apparatus that assesses spontaneous forelimb motor use. In this task, a rat is placed in a cylindrical apparatus, where the rat will spontaneously rear and contact the wall of the cylinder with its forelimbs. These contacts are considered forelimb motor use and quantified during video analysis after testing. Another cost-efficient motor task implemented is the beam-walk task, which assesses forelimb control, hindlimb control and locomotion. This task involves a rat walking across a wooden beam allowing for the assessment of limb motor control through analysis of forelimb slips, hindlimb slips and falls. Assessment of learning and memory is completed with Morris water maze for this behavioral paradigm. The protocol starts with spatial learning, whereby the rat locates a stationary hidden platform. After spatial learning, the platform is removed and both short-term and long-term spatial reference memory is assessed. All three of these tasks are sensitive to behavioral differences and completed within 28 days for this model, making this paradigm time-efficient and cost-efficient.

To investigate the co-morbid Alzheimer&#39;s disease (AD) and stroke condition in a novel model, three behavior tasks are described that assess both motor control and cognitive behaviors. These tasks include the beam-walk task, cylinder task and Morris water maze.

Motor und Hippokampus-Dependent Spatial Learning und Referenz-Gedächtnis-Bewertung in einem transgenen Mausmodell der Alzheimer-Krankheit mit Schlaganfall

Alzheimer&#39;s disease (AD) is a debilitating neurodegenerative disease that results in neurodegeneration and memory loss. While age is a major risk ...

Medizin

Functional Magnetic Resonance Spectroscopy at 7 T in the Rat Barrel Cortex During Whisker Activation

Nuclear magnetic resonance (NMR) spectroscopy offers the opportunity to measure cerebral metabolite contents in vivo and noninvasively. Thanks to technological developments over the last decade and the increase in magnetic field strength, it is now possible to obtain good resolution spectra in vivo in the rat brain. Neuroenergetics (i.e., the study of brain metabolism) and, especially, metabolic interactions between the different cell types have attracted more and more interest in recent years. Among these metabolic interactions, the existence of a lactate shuttle between neurons and astrocytes is still debated. It is, thus, of great interest to perform functional proton magnetic resonance spectroscopy (1H-MRS) in a rat model of brain activation and monitor lactate. However, the methyl lactate peak overlaps lipid resonance peaks and is difficult to quantify. The protocol described below allows metabolic and lactate fluctuations to be monitored in an activated brain area. Cerebral activation is obtained by whisker stimulation and 1H-MRS is performed in the corresponding activated barrel cortex, whose area is detected using blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD fMRI). All steps are fully described: the choice of anesthetics, coils, and sequences, achieving efficient whisker stimulation directly in the magnet, and data processing.

After checking by blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD fMRI) that the corresponding somatosensory barrel field cortex area (called S1BF) is correctly activated, the main goal of this study is to quantify lactate content fluctuations in the activated rat brains by localized proton magnetic resonance spectroscopy (1H-MRS) at 7 T.

Funktionelle Magnet-Resonanz-Spektroskopie bei 7 T in der Ratte Barrel Cortex während der Whisker-Aktivierung

Nuclear magnetic resonance (NMR) spectroscopy offers the opportunity to measure cerebral metabolite contents in vivo and noninvasively. Thanks to ...

Surgical Labyrinthectomy of the Rat to Study the Vestibular System

To study the vestibular system or the vestibular compensation process, a number of methods have been developed to cause vestibular damage, including surgical or chemical labyrinthectomy and vestibular neurectomy. Surgical labyrinthectomy is a relatively simple, reliable, and rapid method. Here, we describe the surgical technique for rat labyrinthectomy. A postauricular incision is made under general anesthesia to expose the external auditory canal and the tympanic membrane, after which the tympanic membrane and the ossicles are removed without the stapes. The stapes artery, which is located between the stapes and the oval window, is a vulnerable structure and must be preserved to obtain a clear surgical field. A hole to fenestrate the vestibule is made with a 2.1-mm drill bur superior to the stapes. Then, 100% ethanol is injected through this hole and aspirated several times. Meticulous dissection under a microscope and careful bleeding control are essential to obtain reliable results. Symptoms of vestibular loss, such as nystagmus, head tilting, and a rolling motion, are seen immediately after surgery. The rotarod or rotation chair test can be used to objectively and quantitatively evaluate the vestibular function.

This protocol describes the surgical labyrinthectomy of a rat, which is a useful method for studying the vestibular system.

Chirurgische Labyrinthectomy der Ratte das vestibuläre System untersuchen

To study the vestibular system or the vestibular compensation process, a number of methods have been developed to cause vestibular damage, including ...

Establishment of Acute Pontine Infarction in Rats by Electrical Stimulation

Pontine infarction is the most common stroke subtype in the posterior circulation, while there lacks a rodent model mimicking pontine infarction. Provided here is a protocol for successfully establishing a rat model of acute pontine infarction. Rats weighing about 250 g are used, and a probe with an insulated sheath is injected into the pons using a stereotaxic apparatus. A lesion is produced by the electrical stimulation with a single pulse. The Longa score, Berderson score, and beam balance test are used to assess neurological deficits. Additionally, the adhesive-removal somatosensory test is used to determine sensorimotor function, and the limb placement test is used to evaluate proprioception. MRI scans are then used to assess the infarction in vivo, and TTC staining is used to confirm the infarction in vitro. Here, a successful infarction is identified that is located in the anterolateral basis of the rostral pons. In conclusion, a new method is described to establish an acute pontine infarction rat model.

Presented here is a protocol for establishing acute pontine infarction in a rat model via electrical stimulation with a single pulse.

Einrichtung eines akuten Pontininfarkts bei Ratten durch elektrische Stimulation

Pontine infarction is the most common stroke subtype in the posterior circulation, while there lacks a rodent model mimicking pontine infarction. Provided ...

rmTBI-Induktion bei Mäusen über eine geschlossene Kopfverletzungsmethode

Modified Mouse Model of Repetitive Mild Traumatic Brain Injury Incorporating Thinned-Skull Window and Fluid Percussion

Mild traumatic brain injury is a clinically highly heterogeneous neurological disorder. Highly reproducible traumatic brain injury (TBI) animal models with well-defined pathologies are urgently needed for studying the mechanisms of neuropathology after mild TBI and testing therapeutics. Replicating the entire sequelae of TBI in animal models has proven to be a challenge. Therefore, the availability of multiple animal models of TBI is necessary to account for the diverse aspects and severities seen in TBI patients. CHI is one of the most common methods for fabricating rodent models of rmTBI. However, this method is susceptible to many factors, including the impact method used, the thickness and shape of the skull bone, animal apnea, and the type of head support and immobilization utilized. The aim of this protocol is to demonstrate a combination of the thinned-skull window and fluid percussion injury (FPI) methods to produce a precise mouse model of CHI-associated rmTBI. The primary objective of this protocol is to minimize factors that could impact the accuracy and consistency of CHI and FPI modeling, including skull bone thickness, shape, and head support. By utilizing a thinned-skull window method, potential inflammation due to craniotomy and FPI is minimized, resulting in an improved mouse model that replicates the clinical features observed in patients with mild TBI. Results from behavior and histological analysis using hematoxylin and eosin (HE) staining suggest that rmTBI can lead to a cumulative injury that produces changes in both behavior and gross morphology of the brain. Overall, the modified CHI-associated rmTBI presents a useful tool for researchers to explore the underlying mechanisms that contribute to focal and diffuse pathophysiological changes in rmTBI.

Autor im Rampenlicht: Optimierung von Nagetiermodellen zur Untersuchung der Mechanismen und der Rehabilitation bei wiederholten leichten traumatischen Hirnverletzungen

This protocol presents a modified mouse model of repetitive mild traumatic brain injury (rmTBI) induced via a closed-head injury (CHI) method. The approach features a thinned-skull window and fluid percussion to reduce the inflammation commonly caused by meninges exposure, along with improved reproducibility and accuracy in modeling rmTBI in rodents.

Modifiziertes Mausmodell für repetitives leichtes Schädel-Hirn-Trauma mit verdünntem Schädelfenster und flüssiger Perkussion

Mild traumatic brain injury is a clinically highly heterogeneous neurological disorder. Highly reproducible traumatic brain injury (TBI) animal models ...