This study was supported by the American Heart Association (IRG 14330015, PRE 16850005, PRE 20380386, EIA 0740129N), and the National Institutes of Health (RR 2865AR; P20 RR 016477).

Todos los procedimientos descritos a continuación han sido revisados ​​y aprobados por el Comité de Cuidado y Uso de Animales Institucional de la Ciencias de la Salud de la Universidad Centro de Virginia Occidental. 1. Selección de Modelo Animal NOTA: Las especies más comúnmente utilizados en el modelo UCMS incluyen Sprague Dawley, y ratas Wistar y de la BALB / cJ ratón; otros modelos murinos han demostrado una eficacia limitada (DBA / 2, C57BL / 6). Sin embargo, una cuidadosa consideración se debe dar al ratón en particular o cepa de rata de elección, ya que los antecedentes genéticos y la susceptibilidad a los factores de estrés ambientales variar ampliamente entre las especies y han demostrado ser factores críticos que afectan a los resultados del estudio de 11,14,15, 19. <ol><li> Utilice los animales de la edad apropiada (por ejemplo, si el punto final deseado debe ser evaluado en un 17 semanas de edad rata, entonces las ratas deben comenzar el protocolo UCMS en ~ 9 semanas de edad) ya que este protocolo se lleva a least 7-9 semanas para inducir totalmente los síntomas depresivos. </li><li> Animales de una sola casa sometidos UCMS en jaulas y las instalaciones aprobadas por la IACUC, con comida y comida estándar ad libitum disponibles (salvo disposición contraria de protocolo específico). </li><li> Tenga especial cuidado para asegurar los controles están alojados en una habitación tranquila con una actividad mínima para reducir los efectos de los posibles factores de estrés ambientales desconocidos. </li></ol> 2. Impredecible Protocolo estrés leve crónico NOTA: Los animales sometidos a UCMS son transportados diariamente (&gt; 5 días por semana) a una habitación limpia utilizada para manipulaciones UCMS. Los animales se expusieron a 1 o 2 de los factores de estrés que figuran a continuación cada día. Los factores estresantes se llevan a cabo en un horario aleatorio, y cada estrés se administra durante un mínimo de 3-4 horas (véase la Tabla 1). <ol><li> Humedezca la ropa de cama vertiendo 10.20 oz agua limpia en cada jaula estándar. Ajustar la cantidad de agua en consecuencia para el tamaño de lajaula para amortiguar totalmente la ropa de cama pero no causar acumulación de agua. Residir los animales en jaula húmedo durante 3-4 horas. </li><li> Retire la ropa de cama de cada jaula durante 3-4 horas, después de lo cual los animales son la transición a otro factor de estrés que requieren una jaula vacía (baño de poca profundidad, inclinación jaula) o colocados en una jaula limpia con ropa de cama fresca. </li><li> Jaulas de inclinación a aproximadamente 45 ° (sin ropa de cama) para 3-4 horas. Las jaulas se pueden inclinar con un objeto sólido que se mantendrá en su lugar cuando el animal se mueve alrededor de la jaula. </li><li> Alter 12 horas de luz / 12 horas / ciclos oscuros normales en sucesiones de 30 min períodos que duran 8 horas. Después, devuelva los animales con el ciclo normal. </li><li> Transferir cada animal de su jaula hogar a la de la jaula de un animal vecino que ha sido retirado por 3 hr. </li><li> Quite toda la ropa de cama de cada jaula y añadir agua hasta una profundidad de ~ 0,25 pulgadas para ratones o ~ 0,5 pulgadas para las ratas durante aproximadamente 4 horas. Use agua que está más caliente que la RT (~ 30 ° C) para minimizar la hipotermiapotencial ia. Animales Brevemente secas con una toalla suave en la conclusión de la exposición al agua antes de la colocación en jaulas limpias. </li><li> Exponga animales depredadores olores / sonidos añadiendo mechones de muestra distribuidos aleatoriamente de la piel o la orina (10-20 ml) de una especie de depredadores naturales en la jaula de 3-4 horas. Alternativamente, jugar gruñidos o ruidos depredadores de especies de depredadores naturales en las proximidades de las jaulas de 3 horas. </li><li> Al final de cada período de estrés diario, coloque todos los animales en jaulas limpias y devolverlos a la instalación de la vivienda. </li></ol> 3. Monitoreo de animales / Grooming Puntuaciones <ol><li> Inspeccione cada animal al día durante el desarrollo de las heridas o llagas que pueden requerir tratamiento veterinario. Los animales que desarrollan lesiones leves pueden continuar en el protocolo UCMS en el consentimiento del veterinario. <ol><li> Dos investigadores capacitados en la evaluación de aseo escudo inspeccionar cada animal y asignan una puntuación escudo semanal en una escala de 0-1. Esta puntuación es disuadirminada asignando puntuaciones individuales (0- limpio, 1-sucio) a cada uno de 8 cuerpo de cabeza regiones-, cuello, capa dorsal, capa ventral, cola, patas delanteras, patas traseras, y la región genital. Los mismos investigadores han de realizar esta tarea durante todo el protocolo UCMS para mantener la coherencia en la asignación de puntajes capa. </li><li> Cualquier animal que experimenta una fuerte reducción en el peso corporal (es decir,&gt; 15%) se debe informar al personal veterinario y debe ser retirado del protocolo. </li></ol></li></ol> 4. Pruebas de Comportamiento y parámetros valorados NOTA: Varios métodos de evaluación se puede utilizar para cuantificar cambios en el comportamiento del protocolo UCMS en roedores. <ol><li> Acumulativo Score y estética Escudo. <ol><li> Como se describió anteriormente, una puntuación de aseo capa semanal se asigna para cada animal. </li></ol></li><li> La sacarosa Splash prueba: <ol><li> Colocar el animal en una jaula de líneas puras con un disco de algodón o una toalla para evitar que la ropa de camase adhiera a su pelaje. Rocíe una solución de sacarosa al 10% en el escudo de cada animal cabeza y dorsal y registrar el comportamiento total de aseo durante 5 min. </li><li> Actividad (definida como la limpieza de la piel por lamer o rascar) Grooming se mide por la latencia (tiempo de inactividad entre la primera pulverización y el inicio de la preparación) y la frecuencia (número de veces que preparan una parte del cuerpo en particular). </li></ol></li><li> La sacarosa prueba de preferencia: <ol><li> Habituar a los animales para beber 1% de solución de sacarosa (w / v) 72 hr antes de la prueba y luego proporcionar exposición a dos botellas (solución de sacarosa al 1% frente a agua del grifo en diferentes botellas). Después de la habituación, proporcionar animales con acceso ad libitum a la solución y grifo de agua sacarosa durante 3 horas. Después de 3 horas los volúmenes récord de consumo de solución de sacarosa y agua del grifo y calcular la preferencia sacarosa como: [(consumo de sacarosa) / (consumo de agua + consumo de sacarosa)] × 100. </li></ol></li><li> Tail Suspension Test (Sólo ratones): <ol><li> Supasar los ratones por la cola de una barra estable (20 cm del suelo) con cinta adhesiva (2 cm desde la punta de la cola). Tiempo de inmovilidad registro durante 5 min. Los ratones se considera inmóvil cuando cuelgan pasiva y completamente inmóvil. </li></ol></li><li> La prueba de natación forzada: <ol><li> Coloque los animales en un contenedor (~ 15-20 cm de diámetro para los ratones; ~ de 55-60 cm de diámetro para ratas) llenos de agua a una temperatura de 26 ± 0,5 ° C. Registre la latencia a la primera pelea de la movilidad y el tiempo inmóvil durante el período de prueba de 5 min. Al final de la prueba, coloque el animal mojado en una jaula de explotación en una almohadilla caliente (30-35 ° C) con ropa normal, cubierta por una toalla de papel absorbente hasta que se seque. </li></ol></li><li> Laberinto elevado: <ol><li> Permita que cada animal para explorar el laberinto libremente durante 5 min. Total de entradas de registro en cada brazo, y el tiempo total gastado en cada brazo, de acuerdo con criterios a priori 20. </li></ol></li><li> Locomotor de la actividad: <ol><li> Los niveles de actividad de registro, que se define como el movimiento global, movimientos de bella, movimientos de cría, y la inactividad, por tanto aguda (30 min) y / o crónica (12 hr) períodos de tiempo. Haga esto usando la jaula casa o un nuevo entorno, en función del entorno individuo (aunque la consistencia debe mantenerse) en tiempo real por un observador o post-hoc mediante la reproducción y el análisis de imágenes de la cámara. </li></ol></li></ol> 5. Expansión / Variación del Protocolo UCMS <ol><li> Administrar agentes o retos terapéuticos apropiados para estudiar su capacidad de cualquiera de embotar el desarrollo de los resultados inducidos UCMS (si se inicia antes de tiempo) o para revertir la gravedad de los resultados inducidos UCMS establecidos (si se inicia tarde). Este es dependiente del laboratorio individual o protocolo 11. </li></ol> 6. Las evaluaciones resultado final <ol><li> Tras la conclusión de protocolos UCMS y pruebas de comportamiento, utilizar animales en la posterior experiments de manera que responda a las hipótesis, objetivos o metas del laboratorio individual específicos. NOTA: Como ejemplos, esto puede incluir las respuestas cardiovasculares, inflamatorias o endocrinas al estrés crónico. Por otra parte, las intervenciones terapéuticas se pueden introducir en este momento para evaluar su eficacia y bases mecanicistas. </li></ol>

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The authors have nothing to disclose.

Extensive clinical and epidemiological evidence has indicated that chronic stress is one of the most potent precipitating factors for depression. Repeated exposure to stressors may potentiate individual vulnerability to depression and other neuropsychiatric disorders as a consequence of the psychological and physical demands within the body that accumulate over time. The use of validated preclinical animal models offers a valuable translational tool for studying depression and comorbid diseases. Firstly, an ideal animal ...

Enfermedad mental depresivo es un trastorno neurológico complejo que está actualmente reconocida como una de las principales causas de la carga de la discapacidad y la enfermedad en todo el mundo. El NIMH informa que aproximadamente el 12% de los estadounidenses sufren de depresión clínica, con el doble de mujeres afectadas en comparación con los hombres 1. Sólo en los EE.UU., la depresión representa miles de millones de dólares los costes sanitarios directos y un estimado de $ 193 mil millones más en costos indirectos (ganancias baja y pérdida de productividad) 2. Los síntomas de la depresión incluyen anhedonia, los cambios en los ciclos de peso y del sueño, disminución de la actividad física y la higiene personal, sentimientos de desesperanza o culpa, y / o pensamientos recurrentes de muerte o suicidio. Durante la última década, epidemiológica y los estudios clínicos han indicado que la depresión es un factor de riesgo independiente para la enfermedad cardiovascular (ECV) morbimortalidad 3, y es un valor pronóstico más grave de las patologías cardiovasculares, incluyendo untherosclerosis, hipertensión, infarto de miocardio y enfermedad arterial coronaria, independientemente de antecedentes de ECV abierta 4. A pesar del aumento de la prevalencia y el impacto adverso en la salud pública de la depresión, la etiología y relacionados fisiopatología de esta enfermedad es poco conocida y la heterogeneidad de la enfermedad debido a diversos factores (por ejemplo, y los componentes genéticos, biológicos ambientales) ha hecho el diagnóstico clínico difícil definir. La evidencia indica que el estrés psicológico irresoluble es un factor importante que contribuye para el desarrollo de enfermedades depresivas, y también puede ser un factor que une la depresión patógena potente y ECV, en parte debido a la interrupción y la desregulación del eje hipotalámico-pituitario-adrenal (HPA) 5,6. La disfunción del eje HPA es un mecanismo importante que se ha relacionado con los cambios conductuales y fisiológicos observados en la depresión y el desarrollo de varios factores de riesgo de ECV, incluyendodislipidemia, la obesidad, la diabetes y 7. Múltiples modelos preclínicos de depresión se han desarrollado en un intento de replicar el mecanismo de la alteración de la actividad del eje HPA característico de la depresión clínica; tales modelos proporcionan un medio validados para la investigación de los cambios de comportamiento, neurológicos y fisiológicos asociados con el estrés crónico y agudo en los animales. La validez de un modelo animal de la enfermedad se basa en la relevancia de la etiología y la progresión del diseño del modelo y su capacidad para recapitular anatómicos, neurofisiológicos, y las características de comportamiento observados en las enfermedades humanas. Además, las respuestas a los tratamientos preclínicos (tales como SSRIs) deben producir resultados similares a los observados en entornos clínicos. Varios modelos animales de depresión inducida por el estrés se utilizan actualmente en la investigación, como la indefensión aprendida, el estrés primeros años de vida, el estrés y la derrota social. Sin embargo, cada uno de estos modelos tiene desventajas inherentesque disminuyen su eficacia traslacional 8. En las dos últimas décadas, el protocolo de impredecibles crónica estrés leve (UCMS) ha surgido como uno de los modelos más traslación relevantes para el estudio de la fisiopatología de la depresión en roedores 9. Este modelo se basa en el concepto fundamental que la exposición crónica a factores de estrés interrumpe sistemas de respuesta al estrés y en última instancia conduce al desarrollo de los trastornos depresivos. Durante el protocolo UCMS, los animales son expuestos a una serie aleatoria de factores de estrés ambientales y sociales leves sobre una base diaria. Un factor crucial que mejora la pertinencia de este modelo para situaciones humanas radica en el alto grado de imprevisibilidad y la incontrolabilidad de los factores de estrés, así como el momento en que se introducen. Además, el protocolo UCMS utiliza sólo factores de estrés leves, en lugar de confiar en la vida temprana o estímulos físicos agresivos. Durante un período de exposición UCMS, conductas depresivas desarrollan y son comparables a Clinsíntomas ical, incluyendo disminución de la capacidad de respuesta a las recompensas (anhedonia), cambios en la actividad física y el comportamiento de investigación (impotencia y desesperanza), el deterioro del estado de la capa y la actividad sexual alterada 10. Casi todos los síntomas demostrables de la depresión se han reportado el uso de este modelo, y los estudios han demostrado que estos comportamientos persisten durante varias semanas después de la cesación de estrés. Además, estos comportamientos depresivos inducidos por UCMS gradualmente pueden ser reverenciados por crónica, pero, el tratamiento no agudo con antidepresivos particulares, lo que sugiere efectos neurológicos similares de mejora terapéutica que refleja estrechamente la acción y la eficacia clínica variable de estos agentes en los seres humanos 11,14- 18. Aquí, se presenta una descripción detallada del protocolo UCMS y describimos los resultados típicos de comportamiento y vasculares en ratones.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Temporary animal cages with lids</td>
			<td>n/a</td>
			<td>n/a&#160;</td>
			<td>Provided by your animal care facility</td>
		</tr>
		<tr>
			<td>Rodent bedding</td>
			<td>n/a</td>
			<td>n/a&#160;</td>
			<td>Provided by your animal care facility</td>
		</tr>
		<tr>
			<td>Predator fur or urine</td>
			<td>n/a</td>
			<td>n/a&#160;</td>
			<td>Provided by your animal care facility</td>
		</tr>
		<tr>
			<td>Rodent cage drinking bottles</td>
			<td>n/a</td>
			<td>n/a&#160;</td>
			<td>Provided by your animal care facility</td>
		</tr>
		<tr>
			<td>1000 ml graduated cylinder</td>
			<td>variable</td>
			<td>variable</td>
			<td>This is optional.&#160; Any container from which a known quantiity of water can be poured will be appropriate</td>
		</tr>
		<tr>
			<td>Wooden blocks cut from 2x4</td>
			<td>variable</td>
			<td>variable</td>
			<td>8 inch sections are cut to facilitate cage tilt procedures</td>
		</tr>
		<tr>
			<td>Soft paper towels</td>
			<td>n/a</td>
			<td>n/a&#160;</td>
			<td>Provided by your institution</td>
		</tr>
		<tr>
			<td>Small spray bottle&#160;</td>
			<td>Walmart</td>
			<td>n/a&#160;</td>
			<td>100-200 ml volume is sufficient, used for sucrose splash test</td>
		</tr>
		<tr>
			<td>Medium (mice) or large (rats) plastic tubs for swim testing</td>
			<td>Walmart</td>
			<td>variable</td>
			<td>Should be of sufficient depth that the animals cannot touch bottom (e.g., 2 feet)</td>
		</tr>
	</tbody>
</table>

an unpredictable chronic mild stress protocol for instigating depressive symptoms, behavioral changes and negative health outcomes in rodents

El estrés crónico, sin resolver es un factor de riesgo importante para el desarrollo de la depresión clínica. Aunque se han reportado muchos modelos preclínicos de la depresión inducida por el estrés, el estrés leve crónico impredecible (UCMS) protocolo es un modelo de traslación-correspondiente fijado para inducir síntomas conductuales comúnmente asociados con la depresión clínica, como la anhedonia, el comportamiento de acicalamiento alterado, y se enteró de desamparo en los roedores. El protocolo UCMS también induce fisiológica (e .g., Hipercortisolemia, hipertensión) y neurológicos (por ejemplo, anhedonia, indefensión aprendida) cambios que están clínicamente asociados con la depresión. Es importante destacar que los síntomas depresivos inducidos por UCMS se pueden mejorar a través crónica, pero no aguda, el tratamiento con ISRS comunes. Como tal, el protocolo UCMS ofrece muchas ventajas sobre los protocolos de estrés agudo o protocolos que utilizan los factores de estrés más extremas. Nuestro protocolo consiste en exposiciones aleatorios diarios a 7 stre distintassors: ropa de cama húmeda, eliminación de la ropa de cama, inclinación jaula, alteración de los ciclos de luz / oscuridad, tensiones sociales, baño en aguas poco profundas, y sonidos de depredadores / olores. Sometiendo roedores 3-4 horas al día a estos factores estresantes leves durante 8 semanas, se demuestra tanto los cambios conductuales significativos y los resultados de salud pobres en el sistema cardiovascular. Este enfoque permite el interrogatorio a fondo de los neurológicos, conductuales y fisiológicos alteraciones asociadas con la depresión inducida por el estrés crónico, así como para la experimentación de nuevos agentes terapéuticos potenciales o estrategias de intervención.

Un ejemplo de la programación de una semana después del procedimiento UCMS se muestra en la Tabla 1. Cada semana, los factores de estrés fueron asignados al azar para evitar aclamación y asegurar imprevisibilidad del desafío de estrés de cada día. Medidas de depresivo como Comportamientos Después de 8 semanas de UCMS, hubo alteraciones significativas en ambos resultados conductuales y fisiológicos en roedores crónicamen...

Watch this Scientific Journal Video about An Unpredictable Chronic Mild Stress Protocol for Instigating Depressive Symptoms, Behavioral Changes and Negative Health Outcomes in Rodents at JoVE.com

An Unpredictable Chronic Mild Stress Protocol for Instigating Depressive Symptoms, Behavioral Changes and Negative Health Outcomes in Rodents

The unpredictable chronic mild stress (UCMS) protocol is a validated method for studying behavioral and physiological changes associated with chronic stress and depressive symptoms. Eight weeks of imposition of the UCMS protocol induces behavioral changes and poor health outcomes in rodents of either gender.

Un protocolo de estrés leve crónico impredecible para los síntomas depresivos, instigar cambios de comportamiento y los resultados de salud negativos en los roedores

Chronic, unresolved stress is a major risk factor for the development of clinical depression. While many preclinical models of stress-induced depression ...

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Research

JoVE Journal

Behavior

22.2K vistas.  West Virginia University Health Sciences Center. The unpredictable chronic mild stress (UCMS) protocol is a validated method for studying behavioral and physiological changes associated with chronic stress and depressive symptoms. Eight weeks of imposition of the UCMS protocol induces behavioral changes and poor health outcomes in rodents of either gender.

Video: An Unpredictable Chronic Mild Stress Protocol for Instigating Depressive Symptoms, Behavioral Changes and Negative Health Outcomes in Rodents

Using Chronic Social Stress to Model Postpartum Depression in Lactating Rodents

Exposure to chronic stress is a reliable predictor of depressive disorders, and social stress is a common ethologically relevant stressor in both animals and humans. However, many animal models of depression were developed in males and are not applicable or effective in studies of postpartum females. Recent studies have reported significant effects of chronic social stress during lactation, an ethologically relevant and effective stressor, on maternal behavior, growth, and behavioral neuroendocrinology. This manuscript will describe this chronic social stress paradigm using repeated exposure of a lactating dam to a novel male intruder, and the assessment of the behavioral, physiological, and neuroendocrine effects of this model. Chronic social stress (CSS) is a valuable model for studying the effects of stress on the behavior and physiology of the dam as well as her offspring and future generations. The exposure of pups to CSS can also be used as an early life stress that has long term effects on behavior, physiology, and neuroendocrinology.

This article describes the use of chronic resident intruder social stress as an ethologically relevant paradigm to model postpartum depression and anxiety in lactating rodents.

Usando estrés social crónico de Modelo depresión posparto en vacas roedores

Exposure to chronic stress is a reliable predictor of depressive disorders, and social stress is a common ethologically relevant stressor in both animals ...

Investigación

Comportamiento

Nest Building as an Indicator of Health and Welfare in Laboratory Mice

The minimization and alleviation of suffering has moral and scientific implications. In order to mitigate this negative experience one must be able to identify when an animal is actually in distress. Pain, illness, or distress cannot be managed if unrecognized. Evaluation of pain or illness typically involves the measurement of physiologic and behavioral indicators which are either invasive or not suitable for large scale assessment. The observation of nesting behavior shows promise as the basis of a species appropriate cage-side assessment tool for recognizing distress in mice. Here we demonstrate the utility of nest building behavior in laboratory mice as an ethologically relevant indicator of welfare. The methods presented can be successfully used to identify thermal stressors, aggressive cages, sickness, and pain. Observation of nest building behavior in mouse colonies provides a refinement to health and well-being assessment on a day to day basis.

We demonstrate the utility of nest building behavior in laboratory mice as an indicator of welfare. Nest scoring is a sensitive technique that is altered by temperature, illness, and aggression. The time to integrate into nest test (TINT) is a simple cage-side assessment that can detect postoperative pain.

Edificio de la jerarquía como indicador de Salud y Bienestar en ratones de laboratorio

The minimization and alleviation of  suffering has moral and scientific implications. In order to mitigate this  negative experience one must be able to ...

The Forced Swim Test as a Model of Depressive-like Behavior

The goal of the present protocol is to describe the forced swim test (FST), which is one of the most commonly used assays for the study of depressive-like behavior in rodents. The FST is based on the assumption that when placing an animal in a container filled with water, it will first make efforts to escape but eventually will exhibit immobility that may be considered to reflect a measure of behavioral despair. This test has been extensively used because it involves the exposure of the animals to stress, which was shown to have a role in the tendency for major depression. Additionally, the FST has been shown to share some of the factors that are influenced or altered by depression in humans, including changes in food consumption, sleep abnormalities and drug-withdrawal-induced anhedonia. The main advantages of this procedure are that it is relatively easy to perform and that its results are easily and quickly analyzed. Moreover, its sensitivity to a broad range of antidepressant drugs that makes it a suitable screening test is one of the most important features leading to its high predictive validity. Despite its appeal, this model has a number of disadvantages. First, the issue of chronic augmentation is problematic in this test because in real life patients need to be treated for at least several weeks before they experience any relief from their symptoms. Last, due to the aversiveness of the FST, it is important to take into account possible influences it might have on brain structure/function if brain analyses are to be carried out following this procedure.

This protocol describes the forced swim test, which is used for the study of depressive-like behavior in rodents. This procedure involves placing an animal in a container filled with water that eventually will lead to the exhibition of immobility behavior, which is considered to reflect behavioral despair.

La prueba de natación forzada como un modelo de depresivo-como comportamiento

The goal of the present protocol is to describe the forced swim test (FST), which is one of the most commonly used assays for the study of depressive-like ...

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.

El Doble-H Maze: Una prueba del comportamiento robusto para el Aprendizaje y la Memoria en roedores

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 ...

A Mouse Model of Subchronic and Mild Social Defeat Stress for Understanding Stress-induced Behavioral and Physiological Deficits

Stressful life events often increase the incidence of depression in humans. To study the mechanisms of depression, the development of animal models of depression is essential. Because there are several types of depression, various animal models are needed for a deeper understanding of the disorder. Previously, a mouse model of subchronic and mild social defeat stress (sCSDS) using a modified chronic social defeat stress (CSDS) paradigm was established. In the paradigm, to reduce physical injuries from aggressors, the duration of physical contact between the aggressor and a subordinate was reduced compared to in the original CSDS paradigm. sCSDS mice showed increased body weight gain, food intake, and water intake during the stress period, and their social behaviors were suppressed after the stress period. In terms of the face validity of the stress-induced overeating and overdrinking following the increased body weight gain, the sCSDS mice may show some features related to atypical depression in humans. Thus, a mouse model of sCSDS may be useful for studying the pathogenic mechanisms underlying depression. This protocol will help establish the sCSDS mouse model, especially for studying the mechanisms underlying stress-induced weight gain and polydipsia- and hyperphagia-like symptoms.

Here, methods for developing a mouse model of subchronic and mild social defeat stress are described and used to investigate the pathogenic features of depression including hyperphagia- and polydipsia-like symptoms following increased body weight.

Un modelo de ratón de subcrónica y leve estrés Derrota Social para Entender déficits conductuales y fisiológicos inducidos por el estrés

Stressful life events often increase the incidence of depression in humans. To study the mechanisms of depression, the development of animal models of ...

Feeding Experimentation Device (FED): Construction and Validation of an Open-source Device for Measuring Food Intake in Rodents

Food intake measurements are essential for many research studies. Here, we provide a detailed description of a novel solution for measuring food intake in mice: the Feeding Experimentation Device (FED). FED is an open-source system that was designed to facilitate flexibility in food intake studies. Due to its compact and battery powered design, FED can be placed within standard home cages or other experimental equipment. Food intake measurements can also be synchronized with other equipment in real-time via FED's transistor-transistor logic (TTL) digital output, or in post-acquisition processing as FED timestamps every event with a real-time clock. When in use, a food pellet sits within FED's food well where it is monitored via an infrared beam. When the pellet is removed by the mouse, FED logs the timestamp onto its internal secure digital (SD) card and dispenses another pellet. FED can run for up to 5 days before it is necessary to charge the battery and refill the pellet hopper, minimizing human interference in data collection. Assembly of FED requires minimal engineering background, and off-the-shelf materials and electronics were prioritized in its construction. We also provide scripts for analysis of food intake and meal patterns. Finally, FED is open-source and all design and construction files are online, to facilitate modifications and improvements by other researchers.

Feeding Experimentation Device FED: Construction and Validation of an Open-source Device for Measuring Food Intake in Rodents

Feeding Experimentation Device (FED) is an open-source device for measuring food intake in mice. FED can also synchronize food intake measurements with other techniques via a real-time digital output. Here, we provide a step-by-step tutorial for the construction, validation, and usage of FED.

La alimentación de dispositivos Experimentación (FED): construcción y validación de un dispositivo de fuente abierta para la medición de la ingesta de alimentos en roedores

Food intake measurements are essential for many research studies. Here, we provide a detailed description of a novel solution for measuring food intake in ...

An Automated T-maze Based Apparatus and Protocol for Analyzing Delay- and Effort-based Decision Making in  Free Moving Rodents

Many neurological and psychiatric patients demonstrate difficulties and/or deficits in decision making. Rodent models are helpful to produce a deeper understanding of the neurobiological causes underlying the decision-making problems. A cost-benefit based T-maze task is used for measuring decision making in which rodents choose between a high reward arm (HRA) and a low reward arm (LRA). There are two paradigms of the T-maze decision-making task, one in which the cost is a time delay and the other in which it is physical effort. Both paradigms require a tedious and labor-intensive management of experimental animals, multiple doors, pellet reward, and arm choice recordings. In the current work, we invented an apparatus based on traditional T-maze with full automation for pellet delivery, door management and choice recordings. This automated setup can be used for the evaluation of both delay- and effort-based decision making in rodents. With the protocol described here, our lab investigated the decision-making phenotypes of multiple genetically modified mice. In the representative data, we showed that the mice with ablated medial habenular showed aversions of both delay and effort and tended to choose the immediate and effortless reward. This protocol helps to decrease the variability caused by experimenter intervention and to enhance experiment efficiency. In addition, chronic silicon probe or microelectrode recording, fiber-optic imaging and/or manipulation of neural activity can be easily applied during the decision-making task using the setup described here.

This article introduces an automated T-maze apparatus that we invented, and a protocol based on this apparatus for analyzing delay-based decision making and effort-based decision making in free moving rodents.

Un T-laberinto automatizado basado en aparato y protocolo para el análisis de decisiones basado en el retraso y el esfuerzo en roedores en movimiento gratis

Many neurological and psychiatric patients demonstrate difficulties and/or deficits in decision making. Rodent models are helpful to produce a deeper ...

The Unpredictable Chronic Mild Stress Protocol for Inducing Anhedonia in Mice

Depression is a highly prevalent and debilitating condition, only partially addressed by current pharmacotherapies. The lack of response to treatment by many patients prompts the need to develop new therapeutic alternatives and to better understand the etiology of the disorder. Pre-clinical models with translational merits are rudimentary for this task. Here we present a protocol for the unpredictable chronic mild stress (UCMS) method in mice. In this protocol, adolescent mice are chronically exposed to interchanging unpredictable mild stressors. Resembling the pathogenesis of depression in humans, stress exposure during the sensitive period of mice adolescence instigates a depressive-like phenotype evident in adulthood. UCMS can be used for screenings of antidepressants on the variety of depressive-like behaviors and neuromolecular indices. Among the more prominent tests to assess depressive-like behavior in rodents is the sucrose preference test (SPT), which reflects anhedonia (core symptom of depression). The SPT will also be presented in this protocol. The ability of UCMS to induce anhedonia, instigate long-term behavioral deficits and enable reversal of these deficits via chronic (but not acute) treatment with antidepressants strengthens the protocol&#39;s validity compared to other animal protocols for inducing depressive-like behaviors.

Here we present the unpredictable chronic mild stress protocol in mice. This protocol induces a long-term depressive-like phenotype and enables to assess the efficacy of putative antidepressants in reversing the behavioral and neuromolecular depressive-like deficits.

El protocolo de estrés leve crónico impredecible para inducir la Anhedonia en ratones

Depression is a highly prevalent and debilitating condition, only partially addressed by current pharmacotherapies. The lack of response to treatment by ...

Stress-Enhanced Fear Learning, a Robust Rodent Model of Post-Traumatic Stress Disorder

Fear behaviors are important for survival, but disproportionately high levels of fear can increase the vulnerability for developing psychiatric disorders such as post-traumatic stress disorder (PTSD). To understand the biological mechanisms of fear dysregulation in PTSD, it is important to start with a valid animal model of the disorder. This protocol describes the methodology required to conduct stress-enhanced fear learning (SEFL) experiments, a preclinical model of PTSD, in both rats and mice. SEFL was developed to recapitulate critical aspects of PTSD, including long-term sensitization of fear learning caused by an acute stressor. SEFL uses aspects of Pavlovian fear conditioning but produces a distinct and robust sensitized fear response far greater than normal conditional fear responses. The trauma procedure involves placing a rodent in a conditioning chamber and administering 15 unsignaled shocks randomly distributed over 90 minutes (for rat experiments; for mouse experiments, 10 unsignaled shocks randomly distributed over 60 minutes are used). On day 2, rodents are placed in a novel conditioning context where they receive a single shock; then, on day 3 they are placed back in the same context as on day 2 and tested for changes in freezing levels. Rodents that previously received the trauma display enhanced levels of freezing on the test day compared to those that received no shocks on the first day. Thus, with this model, a single highly stressful experience (the trauma) produces extreme fear of the stimuli associated with the traumatic event.

Here we describe the detailed methodology required to conduct stress-enhanced fear learning (SEFL) experiments, a preclinical model of post-traumatic stress disorder, in both rats and mice. The model utilizes aspects of Pavlovian fear conditioning and freezing as an index of enhanced fear in rodents.

Miedo estrés mayor aprendizaje, un modelo de roedor robusto del trastorno por estrés postraumático

Fear behaviors are important for survival, but disproportionately high levels of fear can increase the vulnerability for developing psychiatric disorders ...

Novel Object Recognition and Object Location Behavioral Testing in Mice on a Budget

Ethologically relevant behavioral testing is a critical component of any study that uses mouse models to study the cognitive effects of various physiological or pathological changes. The object location task (OLT) and the novel object recognition task (NORT) are two effective behavioral tasks commonly used to reveal the function and relative health of specific brain regions involved in memory. While both of these tests exploit the inherent preference of mice for the novelty to reveal memory for previously encountered objects, the OLT primarily evaluates spatial learning, which relies heavily on hippocampal activity. The NORT, in contrast, evaluates non-spatial learning of object identity, which relies on multiple brain regions. Both tasks require an open-field-testing arena, objects with equivalent intrinsic value to mice, appropriate environmental cues, and video recording equipment and the software. Commercially available systems, while convenient, can be costly. This manuscript details a simple, cost-effective method for building the arenas and setting up the equipment necessary to perform the OLT and NORT. Furthermore, the manuscript describes an efficient testing protocol that incorporates both OLT and NORT and provides typical methods for data acquisition and analysis, as well as representative results. Successful completion of these tests can provide valuable insight into the memory function of various mouse model systems and appraise the underlying neural regions that support these functions.

Here we provide a protocol which includes comprehensive instructions for the economical establishment of murine object location and novel object recognition behavioral testing, including the design, cost, and construction of required equipment as well as execution of behavioral testing, data collection, and analysis.